NEPHROLOGY

Questions&Answers
Q-1
A 26 year old mountain biker was rescued after being trapped under heavy rocks
for almost 12 hours. His urine is dark and urine is positive for blood on dipstick.
His heart rate is 120 bpm and systolic blood presure is 100 mmHg. Lab results
show a creatinine of 35 micromol/L and urea of 15 mmol/L. What is the SINGLE
most appropriate management?

A. Dialysis
B. Intravenous normal saline
C. Intravenous dextroes
D. Intravenous KCl
E. Pain relief

ANSWER:
Intravenous normal saline

EXPLANATION:
This patient here has attained severe crush injuries which has lead to rhabdomyolysis
which results from skeletal muscle breakdown, with release of its contents, one of which
is myoglobin into the circulation. Myogloglbin has heme which results in a positive
dipstick for blood. Myoglobin is nephrotoxic and can cause a worsening acute kidney
injury. It is important to rehydrate the patient to decrease the duration of contact
between myoglobin and the kidney tubules.

RHABDOMYOLYSIS
Rhabdomyolysis results from skeletal muscle breakdown, with release of its contents
into the circulation, including myoglobin, potassium, phosphate, urate and creatinine
kinase (CK).
Aetiology
• Suden, severe crush injury
• Status epilepticus
• Severe exertion
Important presentations to remember for the exam
• Elderly patient with history of fall followed by long duration on the floor
• Mountain biker rescued from being trapped under heavy rocks for many hours
• Trapped under a fallen wardrobe for several hours
• IV drug user found on floor not moving for a few days
• Marathon runner who just completed a long-distance run
Two complications you need to remember for rhabdomyolysis
• Acute kidney injury
• Hyperkalaemia

There is often enough pigment release in the bloodstream to cause nephrotoxicity. The
degree of toxicity is related to the duration of contact of the tubular cells with myoglobin.
This toxicity is compounded by dehydration as well. Example, a person who has run a
marathon has both myoglobin release as well as poor kidney perfusion. Both
dehydration and release of myoglobin increase the risk of acute kidney injury.

One of the most important complications to recognise for rhabdomyolysis is

hyperkalaemia and thus rhabdomyolysis is often a medical emergency.

Laboratory testing
The most important test when there has been a severe crush injury and the
rhabdomyolysis is potentially life threatening is an ECG or potassium level.

This implies that you know how a patient with rhabdomyolysis will die. Acidosis and
hyperkalemia can lead to an arrhythmia. If there are peaked T-waves on the ECG, you
will give calcium chloride or calcium gluconate.

The best initial test that is specific for rhabdomyolysis is a urinalysis in which you find a
dipstick that is positive for blood but in which no red cells are seen. This is a False +ve
dipstick haematuria. This is because myoglobin can react with the reagent on the
dipstick and come out as if there were red cells present. Hemoglobin will do the same
thing. The dipstick of the urinalysis cannot distinguish among hemoglobin, myoglobin,
and red blood cells. This is because myoglobin has heme in it.

Rhabdomyolysis is confirmed with a markedly elevated serum CPK level. Elevated

serum CPK is a biochemical marker of skeletal muscle neurosis.

Rhabdomyolysis is associated with a very rapidly rising creatinine level. This is because
of both renal failure as well as the massive release of muscle products.
Treatment
• Calcium chloride/gluconate.
o If there are ECG abnormalities from the hyperkalaemia the best initial therapy is
calcium chloride or gluconate
• Intravenous fluid rehydration
o Priority to prevent AKI.
o This decreases the duration of contact between the nephrotoxic myoglobin and
the kidney tubule.
• Intravenous sodium bicarbonate
o Used to alkalinize urine to pH >6.5, to stabilize a less toxic form of myoglobin
o Alkalinizing the urine with bicarbonate may help prevent the precipitation of the
pigment in the tubule
• Dialysis
o Only needed in severe cases
Q-2
A 52 year old known diabetes mellitus presents to the Emergency Department
with a sudden onset of pain in the left loin and haematuria. An ultrasound scan
shows a 7 mm stone in left lower ureter. Diclofenac was administered for the
renal colic pain and nifedipine and prednisolone was prescribed as initial
treatment as part of an expulsive therapy. He returns to the emergency
department the following day with worsening pain, vomiting and a history of
having passed two stones. A repeat ultrasound scan reveals hydronephrosis in
the left ureter and the presence of stones. His renal function test indicate an
acute kidney injury. He has a heart rate of 100 beats/minute and a temperature of
38.5 C. What is the SINGLE most appropriate management?

A. Repeat a similar regimen

B. Administer an alpha blocker
C. Extracorporeal shock wave lithotripsy
D. Open surgery
E. Percutaneous nephrostomy

ANSWER:
Percutaneous nephrostomy

EXPLANATION:
This acute kidney injury and hydronephrosis are indicative of an obstructive uropathy.
Percutaneous nephrostomy would be the best intervention to temporarily decompress
the renal collecting system.

ESWL becomes extremely less effective once the stone goes upto 2-3 mm in size.
Less than 50% chance of success. This patient has AKI, a very large stone which is
clearly obstructive uropathy, and therefore urgent percutaneous nephrostomy is
indicated.

PERCUTANEOUS NEPHROSTOMY
This is used as a temporary relief of ureteric obstruction where ureteric stones fail to
respond to analgesics and where renal function is impaired due to the stone. It is an
intervention that decompresses the renal collecting system by placing a catheter,
through the skin, into the kidney, under local anaesthetic. This catheter allows the urine
to drain from the kidney into a collecting bag, outside the body. Another method that is
often used to relieve ureteric obstruction is an insertion of a JJ stent.

The function of a percutaneous nephrostomy is to bypass the ureteric obstruction and

therefore relieve the pain associated with the obstruction.

The percutaneous nephrostomy tube can restore efficient peristalsis to the ureteric wall
and in some cases this allows the stone to pass down and out of the ureter with the
nephrostomy in situ, however in many instances, it simply sits where it is and
subsequent definitive management to remove the stone is still required.
Q-3
A 6 year old boy presents to the paediatric outpatient clinic with a two day history
of dramatic weight gain and bodily swelling, particularly in his lower limbs. He
also had bilaterally puffy eyes two days ago, which he was given some
antihistamine syrup for, but they have not improved his symptoms. He is
otherwise happy and healthy. His mother reports an uneventful pregnancy and
he was delivered via elective Caesarean section at 38 weeks of gestation. He has
no medical problems and he is on the 50th centile on all of his growth charts. He
takes no chronic medication. The mother reports no significant family history of
renal problems. Analysis of the patient’s urine sample was done and is
significant for 3+ proteinuria. What is the SINGLE next best investigation?

A. Serum albumin levels

B. Repeat urine analysis
C. Refer to nephrology
D. Refer to dietician
E. Utrasound KUB (kidneys, ureters, bladder)

ANSWER:
Serum albumin levels

EXPLANATION:
The patient’s urinalysis shows significant proteinuria and to confirm the diagnosis of
nephrotic syndrome, the next best step would be to check the serum albumin level
(which will be low in this case). The patient’s weight gain and his limb swelling is due to
oedema. The definition of nephrotic syndrome includes both massive proteinuria and
hypoalbuminaemia.

The cause of this patient’s proteinuria is most likely to be minimal change disease. The
incidence is higher in children between 2 to 5 years of age. In children, facial swelling is
a common presenting feature. However, the oedema may progress to involve the
whole body. Minimal change glomerulonephritis nearly always presents as nephrotic
syndrome, accounting for the majority of cases in children and about a quarter of cases
in adults. Most cases are idiopathic and respond well to steroids.

There is no need to repeat the urine analysis as it already confirms proteinuria. The
next best step would be to check for hypoalbuminaemia. Once the diagnosis is
confirmed, the child can be referred to the nephrology department for further
investigations and treatment.

Q-4
A 23 year old intravenous drug user with known human immunodeficiency virus
infection and ongoing alcohol dependence was found on the floor by his friend.
According to a neighbour, the last time the patient was seen was two days ago.
On examination, he is found to be very confused and disoriented. His blood tests
show:

Sodium 137 mmol/L

Potassium 5.7 mmol/L
Urea 45 mmol/L
Creatinine 1100 mmol/L

What is the SINGLE best investigation to perform next?

A. Full blood count

B. Blood cultures
C. Abdominal Ultrasound scan
D. Creatinine kinase
E. Amylase

ANSWER:
Creatine kinase

EXPLANATION:
Option D. Creatine Kinase is the correct answer as this patient likely has
rhabdomyolysis. Creatine kinase is the investigation used to help diagnose this and
rhabdomyolysis can result in severe acute kidney injury with life threatening
hyperkalaemia if left untreated as well as peramanent kidney damage. Given that the
patient had been seen two days ago he may have been laying on the floor for up to two
days which is a very high risk of rhabdomyolysis. Furthermore, as a drug user, he may
have used stimulant drugs that would also result in rhabdomyolysis.

Rhabdomyolyisis can be the result of muscle ischaemia due to tissue compression in

cases of prolonged immobilization, such as comatose situations after an overdose of
drugs.
Option A. A full blood count is incorrect. Although this may be useful to us in some
way, in this case it is not the single best answer as it does not direct our steps in
management greatly or help us find a cause for this presentation or address the main
concern in this patient which is the acute kidney injury and rhabdomyolysis.

Option B. Blood cultures is incorrect. This is for the same reason as option A.

Option C. Abdominal ultrasound scan is incorrect. Although this imaging is non-

invasive and would potentially give us a picture of the kidneys, it is not entirely
necessary as the next step in investigating this patient. It would not help us to diagnose
rhabdomyolysis at all. It would be helpful later on to check for any gross structural
damage to the kidney.

Option E. Amylase is incorrect as in this case it would not help further the management
or diagnosis in this case. Amylase is usually used as a blood test when we are
suspicious of pancreatitis. In this case, there is no clear story of abdominal pain or
vomiting, which are classic as well as common features of pancreatitis.

Q-5
An 18 year old man reports having several episodes of visible haematuria over
the last 24 hours. There is no history of abdominal pain or loin pain. These
typically seem to occur within a day or two of developing an upper respiratory
tract infection. Urine testing by dipstick shows albumin and blood. What is the
SINGLE most likely diagnosis?

A. IgA nephropathy
B. Heonch-Scholein purpura
C. Minimal change nephropathy
D. Wilson’s disease
E. Post-streptococcal glomerulonephritis

ANSWER:
IgA nephropathy

EXPLANATION:
IgA nephropathy (Berger's disease)
Features
• Young male, recurrent episodes of macroscopic haematuria
• Typically usually with an upper respiratory tract infection or, less often,
gastroenteritis. Most patients have a history of an upper respiratory tract infection
and, either at the onset or within the first 24-48 hours, there is gross haematuria that
lasts for less than three days. The urine is red or brown and there may also be loin
pain.
• Alternatively, there may be no symptoms but urine shows erythrocytes, casts and
proteinuria.
• It is associated with a number of other diseases, including Henoch-Schönlein
purpura.
• Of those that do not remit, there is a slow progression to ESKD.
Differentiating between IgA nephropathy and post-streptococcal
glomerulonephritis

IgA nephropathy Post-streptococcal glomerulonephritis

• Develops 1-2 days after URTI • Develops 1-2 weeks after URTI
• Main symptom – Haematuria • Main symptom – Proteinuria
• Young males • Associated with a low complement
levels

Q-6
A 27 year old lady was admitted with fever, rigors, and right loin pain. A dipstick
urinalysis was positive for blood, leukocyte esterase and nitrites. A midstream
specimen of urine (MSU) was sent for culture. She has no medical history of
significance. What is the SINGLE appropriate action?

A. Start antibiotics immediately

B. Wait for culture results to start antibiotics
C. Encourage good fluid intake
D. Computerised tomography of kidney, ureter and bladder
E. Ultrasound and X-ray of kidney, ureter and bladder

ANSWER:
Start antibiotics immediately

EXPLANATION:
Patients with suspected acute pyelonephritis should be started with empirical antibiotics
immediately. The antibiotic choice depends on local guidelines however ciprofloxacin or
co-amoxiclav intravenously would be a good choice here if asked. Antibiotics can be
reviewed or changed after the cultures and sensitivities are available.

Good hydration is also advised, however, antibiotics are still a more appropriate action
in this scenario. Maintaining a high urine output helps resolve acute pyelonephritis by
flushing the bacteria from the kidney.

ACUTE PYELONEPHRITIS
Pyelonephritis is an inflammation of the kidney and renal pelvis caused by ascending
urinary tract infections.

Risk factors
- Structural renal abnormalities, including vesicoureteric reflux (VUR)
- Calculi and urinary tract catheterisation
- Stents or drainage procedures
- Pregnancy
- Diabetes
- Primary biliary cirrhosis
- Neuropathic bladder
- Prostate enlargement
Presentation
- Onset is rapid with symptoms appearing over a day or two
- Unilateral or bilateral loin pain, suprapubic pain or back pain
- Fever is variable but can be high enough to produce rigors
- Nausea, vomiting
- Accompanying symptoms suggestive of a lower UTI (frequency, urgency, suprapubic
pain, urethral burning or pain on voiding)

Investigations
- Urinalysis to look for blood, protein, leukocyte esterase and nitrite.
- Midstream specimen of urine (MSU) for microscopy and culture – (this should be done
preferably before starting empirical antibiotics)
o .For children, the collection may need to be clean catch, catheter or suprapubic
aspiration.

Management
• Usually requires admission
• Antibiotics
o Empirical antibiotic treatment whilst awaiting culture and sensitivity

Antibiotic choice
Antibiotics are given according to your local antibiotic policy, but NICE has advised the
following:
• Women who are not pregnant, men, and people with indwelling catheters
o Ciprofloxacin 500 mg twice daily for 7 days
o Alternatively, co-amoxiclav 625 mg three times a day for 14 days
• Children
o Co-amoxiclav as first-line treatment, with cefixime as second-line
• Pregnant women who do not require admission (unlikely to be asked in the exam)

If the patient is being admitted, intravenous antibiotics would be suitable.

Remember
• 80% of infections are due to E. coli

Q-7
A 50 year old woman who is newly diagnosed with hypertension complains of
urinary frequency and dysuria for the past two weeks. Urinalysis reveals the
presence of white blood cells and protein. What is the most appropriate
management for her?

A. Imipramine
B. Furosemide
C. Vaginal oestrogen cream
D. Trimethoprim
E. Clotrimoxazole

ANSWER:
Trimethoprim
EXPLANATION:
This lady has a urinary tract infection. The hypertension given in this stem has no
relationship to the management and it is given to throw you off. Trimethopgrim would
be the most appropriate choice given that it is an antibiotic used to treat UTI.

Q-8
A 32 year old miner was rescued after being trapped under a fallen rock for 4
hours. After applying a bladder catheter, 145-20 ml of reddish brown urine was
obtained. He has a systolic blood pressure of 100 mmHg and a pulse rate of 130
beats/minute. What is the SINGLE most appropriate next management?

A. Dopamine intravenously
B. Intravenous fluids
C. Furosemide intravenously
D. 20% Mannitol intravenously
E. Intravenous antibiotics

ANSWER:
Intravenous fluids

EXPLANATION:
The patient has developed rhabdomyolysis as he was trapped under a fallen rock for
several hours. The reddish brown sometimes referred to as ‘tea-coloured’ urine is due
to myoglobin in the urine. Due to the danger of acute renal failure, intravenous fluids
would be an appropriate option to avoid further renal compromise.

Q-9
A 65 year old diabetic woman is undergoing a coronary angiography. What is the
SINGLE most appropriate measure to prevent contrast induced nephropathy?

A. Administer furosemide
B. Administer dextrose
C. Administer 0.45% saline
D. Administer 0.9% saline
E. Administer corticosteroids

ANSWER:
Administer 0.9% saline

EXPLANATION:
Contrast induced nephropathy
Prevention
Dehydration can increase your risk of contrast induced nephropathy. Thus, drink fluids
to prevent dehydration. IV normal saline can help prevent dehydration as well. The
evidence supporting their use is strong. In practice, 0.9% NaCl 1mL/kg/h for 12h pre-
and 12h post-procedure is given to patients.

There are some studies that show that N-acetylcysteine (NAC) may be of some use to
prevent contrast induced nephropathy but it is unlikely to be asked in a basic exam like
PLAB part 1.
Q-10
A 56 year old man presents with periorbital and pedal oedema. 24-hour urine
shows 8 g of protein and his serum cholesterol is 7 mmol/L. A recent serum
creatinine performed showd a level of 258 micromol/L from a baseline of 180
micromol/L. Renal biopsy was performed however, results have not come back
yet. What is the SINGLE most likely cause of his nephrotic syndrome?

A. Minimal change disease

B. Membranous glomeurolonephropathy
C. Focal segmental glomerulosclerosis (FSGS)
D. IgA nephropath
E. Mesangiocapillary

ANSWER:
Membranous glomerulonephropathy

EXPLANATION:
Membranous nephropathy is the most common form of idiopathic nephrotic syndrome in
this age group. It has a peak incidence in the 4th to 6th decades of life.

The top 4 causes of the nephrotic syndome in descending order of frequency in adults:
- Membranous nephropathy
- Minimal change nephropathy
- Systemic lupus erythematosus
- Focal and segmental glomerulosclerosis.

If the stem includes a non-diabetic causation adult or otherwise unspecified like in this
stem, with nephrotic syndrome, the answer should always be membranous nephropathy
when asked about the likely cause.

MEMBRANOUS NEPHROPATHY
This occurs when there is widespread thickeningof the glomerular basement
membrane. It is the most common form of idiopathic nephrotic syndrome in adults.

Clinical features
• Proteinuria associated with the nephrotic syndrome
• Microscopic haematuria
• Hypertension

75% of membranous nephropathy is idiopathic with 25% of them having a secondary

cause.
Secondary causes include
• Infections
o Endocarditis
o Chronic hepatitis B or C
• Autoimmune diseases
o Systemic lupus erythematosus
• Neoplasms
o Lymphoma
o Breast cancer
• Drugs
o Penicillamine
o NSAIDS

Treatment
Secondary membranous nephropathy
• Treat the underlying cause

Idiopathic membranous nephropathy involves:

• ACE/ARB and diuretics
• Corticosteroids
• Chlorambucil
• Cyclophosphamide
• Cyclosporin

Prognosis
Spontaneous complete remission occurs in up to 30%. Partial remission occurs in 30%
to 40% by 5 years. Around 30-50% of those patients would progress to end stage renal
disease.

Remember the rule of thirds

• 1/3 will have partial remission but will still have chronic membranous
glomerulonephritis
• 1/3 will go into remission
• 1/3 progress to end-stage renal failure

Q-11
A 2 year old boy is brought to the hospital by his mother with the complaints of
diarrhoea and vomiting. He was previously fit and well until a few days ago when
he was treated with antibiotics by his general practitioner for an upper respiratory
tract infection. He no longer has a cough but feels extremely unwell. His
observations show that he is tachycardia and tachypnoeic. His recent blood test
shows:

Sodium 134 mmol/L

Potassium 5.9 mmol/L
Urea 10.1 mmol/L
Creatinine 195 micromol/L

What is the SINGLE likely diagnosis?

A. Acute kidney injury

B. Adrenal insufficiency
C. Gastroenteritis
D. Pyloric stenosis
E. Hypopituitarism

ANSWER:
Acute kidney injury
EXPLANATION:
You may be tempted to choose gastroenteritis as an answer for this question. Although
gastroenteritis is a viable option here given the patient’s symptoms, remember that
prolonged vomiting and diarrhoea cause hypokalaemia and not hyperkalaemia.

Acute kidney injury is the correct answer here as can be seen clearly with the lab
values. Whether this child got an acute kidney injury from his previous upper
respiratory tract infection, from antibiotic use, or from dehydration due to vomiting and
diarrhoea remains unknown. It is worth mentioning that prerenal is the most common
cause of acute kidney injury in children and it would usually occur from hypovolaemia.

Acute kidney injury (AKI), formerly referred to as acute renal failure (ARF), is seen as an
acute reduction in kidney function that results in a decline in glomerular filtration rate
(GFR) leading to retention of urea and other nitrogenous waste products. The urea
would be seen as high and high levels of urea in the blood can result in vomiting or
diarrhoea (or both). Hyperkalaemia is seen as the kidneys are not able to filter out
potassium.

Q-12
A 32 year old man presents with painless haematuria and flank pain. His blood
pressure is 155/98 mmHg. The rest of the physical examination was otherwise
unremarkable. What is the SINGLE most likely diagnosis?

A. Bladder cancer
B. Adult polycystic kidney disease
C. Thrombotic thrombocytopenic purpura (ITP)
D. Prostate cancer
E. Haemolytic uraemic syndrome (HUS)

ANSWER:
Adult polycystic kidney disease

EXPLANATION:
For the purpose of the examination, scenarios with haematuria + hypertension are
almost always polycystic kidney disease (PKD).

Questions often ask about screening test for PKD and give you an option between
genetic testing for PKD1 or an ultrasound scan. The answer should always be an
ultrasound scan. Genetic testing for PKD1 is difficult as the gene is large and there are
hundreds of described mutations. USS screening offers good sensitivity and specificity.

Autosomal dominant polycystic kidney disease

Presentation
- Flank pain
- Haematuria (micro and gross)
- Urinary tract infections (UTIs) and calculi
- Hypertension
- Bilateral kidney enlargement - abdominal examination may reveal enlarged and
palpable kidneys
Other points:
- Gross haematuria following trauma is a classic presenting feature of ADPKD
- Sometimes present with kidney failure (usually in the fourth to sixth decade of life)
- May also present as asymptomatic on screening of family members
- Intracranial aneurysm is an important extrarenal manifestation (an important point that
is commonly asked)

Note: The other extra-renal manifestation are less commonly asked

Diagnosis:
Ultrasound

Treatment
Nonspecific; management of hypertension

Q-13
A 3 year old child presents to A&E with history of bloody diarrhoea and
decreased urination. The mother states that the child developed fever, vomiting,
abdominal pain, and diarrhoea that started 5 days ago. On physical examination,
the patient appears ill. He is pale and lethargic. Laboratory results show:

Haemoglobin 90 g/L
Platelets 80 x 109/L

There was fragmented red cells on blood film. What is the SINGLE most likely
diagnosis?

A. Ulcerative colitis
B. Haemolytic uraemic syndrome
C. Thrombotic thrombocytopenic purpura (TTP)
D. Hepatorenal syndrome
E. Sepsis

ANSWER:
Haemolytic uraemic syndrome

EXPLANATION:
Haemolytic uraemic syndrome (HUS)
HUS consists of a triad of haemolytic anaemia, uraemia, and thrombocytopenia.

The anaemia will be intravascular in nature and will have an abnormal blood smear
showing schistocytes, helmet cells, and fragmented red cells.

LDH and reticulocyte count will be elevated and the haptoglobin decreased.

90% are caused by E. coli strain O157. This produces a verotoxin that attacks
endothelial cells. Occurs after eating undercooked contaminated meat.
Signs and Symptoms:
The classical presenting feature is profuse diarrhoea that turns bloody 1 to 3 days later.
It is rare for the diarrhoea to have been bloody from the outset. About 80-90% of
children from whom the organism is isolated will develop blood in the stool. It is usually
at this stage that they are admitted to hospital.

Most adults infected with E. coli O157 remain asymptomatic.

There is often fever, abdominal pain and vomiting

Management
• Treatment is supportive e.g. Fluids, blood transfusion and dialysis if required
• Do not give antibiotics to those with possible HUS. The organism may release more
toxins as it dies if antibiotics are given and may worsen the disease.
• The indications for plasma exchange in HUS are complicated. As a general rule
plasma exchange is reserved for severe cases of HUS not associated with diarrhoea

Q-14
A 26 year old man presents to hospital complaining that his urine has been very
dark recently resembling tea. He had recently been under “the weather” 2 weeks
back and had taken a few days off work with a sore throat and coryzal symptoms.
A urine dipstick returns highly positive for blood and protein. He is admitted for
supportive management. What is the SINGLE most likely diagnosis?

A. Membranous glomerulonephropathy
B. Systemic Lupus Erythematosus
C. Wegener’s granulomatosis
D. Post-streptococcal glomerulonephritis
E. IgA nephropathy

ANSWER:
Post-streptococcal glomerulonephritis

EXPLANATION:
Post-streptococcal glomerulonephritis
Post-streptococcal glomerulonephritis typically occurs 7-14 days following a group A
beta-haemolytic Streptococcus infection (usually Streptococcus pyogenes). It classically
follows a streptococcal sore throat but often occurs after infection elsewhere, e.g.
tonsillitis, pharyngitis (commonly), impetigo, otitis media, and cellulitis.

It is caused by immune complex (IgG, IgM and C3) deposition in the glomeruli. Young
children most commonly affected usually below age 7.

Clinical presentation
Varies from asymptomatic microscopic haematuria through to an acute nephritic
syndrome, with frank haematuria, oliguria, proteinuria, oedema, increased blood
pressure and AKI.

Very commonly patients would describe their urine as smoky, cola, or tea-colored urine.
This abnormal urine color is from hematuria, red cell casts, and proteinuria.
Investigations
- Low C3
- Raised anti-streptolysin O titre
- The most accurate test is the renal biopsy showing "humps" on electron microscopy.
IgG and C3 will be deposited in the mesangium as subepithelial humps. However,
biopsy is rarely needed as treatment is largely supportive with the vast majority
resolving spontaneously.

Q-15
A 24 year old man has just completed a long-distance running event. He
becomes very weak afterward and is brought to the emergency department with
painful muscles and red-brown urine. Urine is positive for blood on dipstick but
without RBC on microscopy. ECG shows a tall T waves, small P waves, and a
widened QRS complex. What is the SINGLE most appropriate initial
management?

A. Intravenous calcium gluconate

B. Intravenous normal saline
C. Intravenous magnesium sulphate
D. Pain relief
E. Oral rehdyration

ANSWER:
Intravenous calcium gluconate

EXPLANATION:
This man has just finished a run of which he was severely exerted. The skeletal muscle
breakdown has resulted in Rhabdomyolysis and thus hyperkalaemia. IV calcium
gluconate needs to be administered first for cardio protection as there are already ECG
changes from the hyperkalaemia.

Q-16
A 2 year old boy has gradual swelling of his face, feet and legs. He feeds poorly
but is noted to have gained weight. There is a foamy appearance of the urine. He
feels fatigue. What is the SINGLE most appropriate investigation?

A. Ultrasound kidneys
B. 24 hour urinary protein
C. Serum calcium
D. Urea and electrolytes
E. Serum glucos

ANSWER:
24 hour urinary protein

EXPLANATION:
This is a case of nephrotic syndrome which is likely caused by minimal change disease.
Minimal change disease has a peak incidence at 2 to 3 years of age. Almost all cases
are idiopathic but a small percentage of cases have identifiable causes like NSAIDs,
toxins, and infections.

Children with minimal change disease often gain weight, as they are excreting less
water in the urine.
Testing the renal function is important however in most cases it would be normal
(hyponatremia is often observed due to water retention). A 24-hour urine measurement
for protein and creatinine clearance is a better answer.

NEPHROTIC SYNDROME
Triad of:
1. Proteinuria (> 3g/24hr) causing
2. Hypoalbuminaemia (< 30g/L) and
3. Oedema

Causes
Primary glomerulonephritis accounts for around 80% of cases
- minimal change glomerulonephritis (causes 80% in children, 30% in adults)
- membranous glomerulonephritis
- focal segmental glomerulosclerosis
- membranoproliferative glomerulonephritis

Systemic disease
- diabetes mellitus
- systemic lupus erythematosus
- amyloidosis

Q-17
A 10 year old boy has been diagnosed with nephrotic syndrome and started on
steroids. 5 days later he presents with flank pain, haematuria and fluctuating
urea levels. A diagnosis of renal vein thrombosis is made. What is the SINGLE
most likely cause for renal vein thrombosis?

A. Protein C deficiency
B. Vasculitis
C. Loss of antithrombin III
D. High oestrogen levels
E. Stasis

ANSWER:
Loss of antithrombin III

EXPLANATION:
Nephrotic syndrome is the combination of proteinuria, oedema and hypoalbuminaemia.
Not only is albumin is lost in the urine, anti-coagulation factors are also lost such as
antithrombin III. A reduction or deficiency in antithrombin III predisposes patients to
venous thromboembolism.

Protein C is present in the urine of nephrotic patients and its deficiency can also
predispose to venous thromboembolism. However, plasma levels remain within normal
limits and it is not thought to be involved in the development of renal vein thrombosis in
these patients.
Treatment of a renal vein thrombosis is with anticoagulation. It is unclear why the renal
vein is susceptible to thrombosis.

The most common cause of nephrotic syndrome in children is minimal change disease.
Q-18
A 79 year old man has anorexia, urinary frequency, hesitancy, and post-void
dribbling. He is also hypertensive, with a blood pressure of 165/110. There are
small kidneys on ultrasound and a creatinine of 170 mmol/L. What is the SINGLE
most likely diagnosis leading to his renal dysfunction?

A. Hypertensive renal disease

B. Prostate cancer
C. Benign prostatic hyperplasia
D. Urinary tract infection
E. Reflux nephropathy

ANSWER:
Hypertensive renal disease

EXPLANATION:
Hypertensive renal disease leads to small, scarred kidneys.

This elderly man has symptoms of prostatism – with anorexia which may suggest
prostatic cancer. However, a large prostate can lead to obstructive nephropathy and
hydronephrosis, not small kidneys

Reflux nephropathy leads to dilated renal pelvis and calyces.

Q-19
A 79 year old man found on the floor unconscious by his neighbours. When the
paramedics arrived at the scene, he gained consciousness with a GCS of 15/15.
His systolic blood pressure with the ambulance crew was 60 mmHg of which the
ambulance crew administered 1.5 L of sodium chloride 0.9%. On arrival to the
Emergency Department, the was resuscitated further. He gives a history of
having severe diarrhoea over the past 2 days.

His venous blood gas shows the following:

pH 7.18
Base excess – 14 mmol/L
Lactate 6.1

His other bloods show:

Haemoglobin 118 g/L
Urea 16 mmol/L
Creatinine 400 micromol/L
eGFR 16
CRP 160 mg/L

What is the SINGLE most likely interpretation of his blood gas?

A. Metabolic acidosis
B. Respiratory acidosis
C. Metabolic acidosis with respiratory compensation
D. Respiratory acidosis with metabolic compensation
E. Mixed acidosis
ANSWER:
Metabolic acidosis

EXPLANATION:
This picture represents metabolic acidosis

• His pH is low – Acidosis

• His base excess is very low – Metabolic acidosis

Diarrhoea can cause a loss of bicarbonate from the body causing metabolic acidosis.
Diarrhoea and sepsis would also exacerbate dehydration and hypovolaemia which may
produce a pre-renal element of acute renal failure which is represented by the high
serum creatinine.

In this case there are many factors which can be seen to contribute to the metabolic
acidosis.

• Diarrhoea – loss of bicarbonates

• Septic shock – build up of lactic acid
• Renal failure – build up of urate

ACUTE KIDNEY INJURY (AKI)

• Characterised by decreasded renal function which occurs over hours to days

• Measured by serum creatinine or urine output

The Kidney Diseases: Improving Globan Outcomes (KDIGO) guidelines define AKI as:
• A rise in creatinine more than 26 micromol/L within 48 hours
• A rise in creatinine more than 1.5x of baseline within 7 days
• A urine output that is less than 0.5 ml/kg/hour for more than 6 consecutive hours

Remember the 5 most common causes of AKI

1. Sepsis
2. Major surgery
3. Cardiogenic shock
4. Other causes of hypovolaemia
5. Drugs

o Remember this mnenomic DAMN drugs (Diuretics, ACE inhibitors/ARBs, metformin,

NSAIDs) – These are potentially nephron-harmful drugs (except metformin which is
not nephrotoxic but still needs to be reduced or stopped in renal impairment)
Q-20
In chronic renal failure, what is the main cause of vitamin D deficiency?

A. Decreased vitamin D absorption in intestines

B. Deficiency of 2 alpha-hydroxyvitamin D
C. Excess vitamin D loss in urine
D. Reduced activity of 1-alpha hydroxylation
E. Unavailability of Vit. D precursors
ANSWER:
Reduced activity of 1-alpha hydroxylation

EXPLANATION:
Patients with kidney disease have reduced activity of the enzyme 1-alpha hydroxylase
in the kidneys, which converts 25-hydroxyvitamin D to its more active form, 1, 25-
dihydroxyvitamin D, and thus patients with kidney disease have traditionally been given
vitamin D replacement with active 1,25-dihydroxyvitamin D or a related analog.

Q-21
A 32 year old woman of 38 weeks gestation complains of feeling unwell with
fever, rigors and abdominal pains. The pain was initially located at the lower
abdomen and was associated with urinary frequency and dysuria. The pain has
now become more generalized specifically radiating to the right loin. She says
that she has felt occasional uternine tightening. CTG is reassuring. What is the
SINGLE most likely diagnosis?

A. Acute fatty liver of pregnancy

B. Acute pyelonephritis
C. Round ligament stretching
D. Cholecystitis
E. Cystitis

ANSWER:
Acute pyelonephritis

EXPLANATION:
Fever, rigor, abdominal pain associated with frequency and dysuria and radiation to the
right loin suggests right sided pyelonephritis. Acute pyelonephritis is more commoon in
pregnancy.

Q-22
A 29 year old lady was admitted with fever, rigors, loin pain and vomiting. A
dipstick urinalysis was positive for blood, leukocyte esterase and nitrites. She
has a history of repeated urinary tract infections, but this time she has blood in
her urine. What is the SINGLE most likely diagnosis?

A. Acute pyelonephritis
B. Chronic pyelonephritis
C. Urinary tract infection
D. Bladder stone
E. Urethritis

ANSWER:
Acute pyelonephritis

EXPLANATION:
The loin pain is suggestive of acute pyelonephritis. Urinary tract infection is not wrong
as acute pyelonephritis is under the category of a urinary tract infection but the more
specific answer would be acute pyelonephritis.
Many doctors would have answered chronic pyelonephritis because of the history of
repeated urinary tract infections. However, chronic pyelonephritis usually has no active
infection. They may present with symptoms secondary to renal failure. Diagnosis is
often from incidental findings during general investigation.
Q-23
A 6 year old boy is brought to the emergency department by his mother because
of swelling on his legs that has been worsening in the last two days. The
swelling is also present in the scrotum and around his eyes. He is generally tired
and his urine is noted to be frothy. Renal biopsy report states no abnormalities
can be seen on light microscopy, however, electron microscopy reveals abnormal
podocytes (fused). What is the SINGLE most likely diagnosis?
A. Thrombotic thrombocytopenic purpura (TTP)
B. Myelodisplastic disease
C. Henoch-Schonlein purpura (HSP)
D. Membranous glomerulonephritis
E. Minimal change disease
ANSWER:
Minimal change disease

EXPLANATION:
The phrase “electron microscopy shows fusion of podocytes“ is key. This tells you that it
can be nothing else but minimal change disease. PLAB questions would likely give a
scenario similar to this where a child is having symptoms of swelling or proteinuria and
a renal biopsy shows fusion of podocytes on electron microscopy.
Minimal change disease
Minimal change disease nearly always presents as nephrotic syndrome, accounting for
75% of cases in children and 25% in adults.
The majority of cases are idiopathic
Features
- Nephrotic syndrome
- Normotension - hypertension is rare
- Renal biopsy: electron microscopy shows fusion of podocytes
Management
- Majority of cases (80%) are steroid responsive
- Cyclophosphamide is the next step for steroid resistant cases

Q-24
A 9 year old boy is brought in by his parents with bilateral periorbital oedema,
ankle swelling and an increase in body weight. What is the SINGLE most likely
diagnosis?
A. Chronic heart failure
B. Nephrotic syndrome
C. Renal failure
D. Acute heart failure
E. IgA glomerulonephritis
ANSWER:
Nephrotic syndrome

EXPLANATION:
This patient most likely has a nephrotic syndrome
• Proteinuria
• Hypoalbuminaemia
• Oedema

The most likely diagnosis is minimal change disease. The peak incidence is around 3-4
years of age, however it can occur in older children. It is steroid responsive in the
majority of cases, however a small number of patients require cyclophosphamide.
The diagnosis of minimal change disease can be made on clinical and biochemical
grounds alone. However, a renal biopsy can be performed which will demonstrate
podocyte fusion and deformity on electron microscopy (and no histologicdal changes
when viewing specimens under light microscopy).
IgA glomerulonephritis causes a nephritis and typically occurs a few days after an upper
respiratory tract infection.
Q-25
A 24 year old male was trying to move his wardrobe when it fell on his thigh. His
two legs were trapped underneath it for several hours before someone was able
to help him get out. When he was seen in the ED his urine was dark and dipstick
was positive for blood. His heart rate is 115 bpm and his systolic blood pressure
is 100 mmHg. Lab results show a creatinine of 320 micromol/L and urea of 13
mmol/L. What is the SINGLE most likely cause of his renal failures?
A. Acetylcholine
B. Drug toxicity
C. Troponin
D. Acetoacetate
E. Myoglobin
ANSWER:
Myoglobin
EXPLANATION:
The trauma to his muscles and being left there for several hours has led to muscle
breakdown which would release myoglobins causing an acute kidney injury which can
be seen by the raised creatinine and urea in this stem.
Q-26
A 79 year old man is brought in by ambulance to the Emergency Department as
he is feeling unwell and short of breath.
His arterial blood gas shows the following:
pH 7.15
pCO2 2.2 kpa
PO2 12 kpa
Base excess -16 mmol/L
Hisother bloods show:
Urea 15 mmol/L
Creatinine 350 micromol/L

What is the SINGLE most likely interpretation of his arterial blood gas?

A. Respiratory compensated metabolic alkalosis

B. Metabolic compensated respiratory acidosis
C. Metabolic compensated respiratory alkalosis
D. Metabolic acidosis
E. Respiratory acidosis

ANSWER:
Metabolic acidosis

EXPLANATION:
Metabolic acidosis with partial respiratory compensation would be the best answer here.
As this is not present, pick metabolic acidosis.

• His pH is low – Acidosis

• His base excess is very low – Metabolic acidosis
• His pCO2 is low – Because of respiratory compensation where lungs are attempting
to clear out carbon dioxide.

One of the causes of a dyspnoeic patient like in this stem is respiratory compensation
for metabolic acidosis. This is usually seen in a patient who is DKA or a patient with
salicylate overdose of which the stem maynot always reveal.

Q-27
A 75 year old female presents to A&E with the history of a fall. On further
questioning, it is revealed that she has had a two year history of frequent falls,
the cause of which she attributes to being clumsier in her old age. On
examination, she appears to be confused and has a three hour history of nausea
and vomiting. She has decreased skin turgor and is found to be oliguric. Her
serum lab values are as follows:
Urea: 15 mmol/L
Creatinine: 210 micromol/L
Creatine kinase: 21223 U/L

What is the SINGLE most likely reason for her increased creatine kinase levels?

A. Dermatomyositis
B. Rhabdomyolysis
C. Chronic kidney injury
D. Urinary tract infection
E. Dementia

ANSWER:
Rhabdomyolysis
EXPLANATION:
The answer that best fits in with this patient’s signs and symptoms is rhabdomyolysis.
She has an acute kidney injury secondary to rhabdomyolysis which was caused by her
history of frequent falls.

The clincher in this stem is the markedly raised serum creatinine kinase, which, in
rhabdomyolysis, is often raised to over 10,000.

One must remember that you do not need to have a crushing injury for rhabdomyolysis
to occur. It can also occur after a fall if left for a long period of time on the floor which
could also cause muscle breakdown. There is no history in this stem of being on the
floor for long duration of time, but one would have to assume so as there is not a better
option given as an answer.

Some may argue that dermatomyositis may also cause a raised creatinine kinase that is
sometimes 50 times more than normal and she could have fallen down frequently due
to proximal muscle weakness. However, this stem does not include any skin
manifestations like Gottron’s papules or heliotrope rash which are often seen in stems
where the answer would be dermatomyositis. Furthermore, the exam writers would
always take into consideration which is a more important diagnosis NOT to miss. If you
miss a diagnosis of dermatomyositis in A&E, no one would penalize you. But if you
miss a diagnosis of rhabdomyolysis which is a medical emergency and life threatening,
a clinical incident would be filed.

Q-28
A 34 year old woman with diabetes mellitus is undergoing a contrast radiography.
What is the SINGLE most appropriate measure that should be taken to prevent
renal damage with contrast dye?

A. Reduce contrast dye

B. Plenty of fluids
C. NSAIDs
D. ACE inhibitors
E. IV dextrose

ANSWER:
Plenty of fluids

EXPLANATION:
Please see Q-9

Q-29
A 65 year old man is being treated for abdominal sepsis with antibiotics and
intravenous fluids. After some time repeat blood tests were performed to check
the progress. Blood tests showed:

Sodium 127 mmol/L

Potassium 3.7 mmol/L
Creatinine 80 mmol/L
Urea 4.3 mmol/L
What is SINGLE most likely cause of these blood test results?

A. Hypertension
B. Sepsis
C. Iatrogenic
D. Liver failure
E. Acute kidney injury

ANSWER:
Iatrogenic

EXPLANATION:
Option C. Iatrogenic is the correct answer as these results are likely due to too much of
an inappropriate fluid being prescribed such as 5% dextrose. In the presence of sepsis
a fluid like Hartmann’s or 0.9% sodium chloride is more appropriate as it will help
replace intravascular volume without dilution or fluid shifts that occur when using a fluid
like dextrose. Avoid using such kinds of fluids in the setting of sepsis as they do more
harm.

Option A. Hypertension is incorrect as high blood pressure does nto cause

hyponatraemia. In fact, hypernatraemia can result in a raised blood pressure in certain
endocrine problems.

Option B. Sepsis is incorrect as this alone is not likely to cause low sodium. There are
certain infections such as atypical respiratory infections like legionella that can result in
hyponatraemia. In this question, they explicitly state this is an abdominal sepsis.

Option D. Liver failure is not correct as there is no indication in this scenario of any liver
symptoms. Although the patient has abdominal sepsis, which is usually biliary sepsis,
there is no mention of any signs of liver disease such as jaundice, and there are no
blood test results that demonstrate deranged liver function.

Option E. Acute kidney injury is incorrect as the creatinine and urea are shown to be
normal in this case. In fact, acute kidney injury can cause a mild hyponatraemia, but
you would have to have deranged renal function also.
Q-30
A 34 year old primigravida who is now 16 weeks gestation attends the antenatal
clinic for a routine check up. She has a blood pressure of 160/100 mmHg. She
has a history of repeated childhood urinary tract infections. What is the SINGLE
most likely cause of her high blood pressure?

A. Essential hypertension
B. Chronic pyelonephritis
C. Acute pyelonephritis
D. Pre-eclampsia
E. Perinephric abscess

ANSWER:
Chronic pyelonephritis
EXPLANATION:
Repeated urinary tract infection in childhood can lead to renal scarring and chronic
pyelonephritis which results in hypertension.

Chronic pyelonephritis
This describes renal scarring which may or may not be related to previous UTI. It is a
radiological, functional, or pathological diagnosis or description.

Causes
• Renal scarring due to previous infection
• Long-term effects of VUR, with or without superimposed infection
• A child with VUR, particularly where there is reflux of infected urine, will develop
reflux nephropathy (which, if bilateral, may cause renal impairment or renal failure).
If the child’s kidneys are examined radiologically, the radiologist will describe the
appearances as those of ‘chronic pyelonephritis’.
• An adult may also develop radiological features of chronic pyelonephritis due to the
presence of reflux combined with high bladder pressures, again particularly where
the urine is infected.

Presentation
- Patients may be asymptomatic or present with symptoms secondary to renal failure.
- Diagnosis is often from incidental findings during general investigation.
- There is usually no active infection.

Appearances on imaging
- Renal ultrasound may show small kidneys with a thin cortex
- Intravenous pyelogram (IVP) may show small kidneys, ureteric and caliceal
dilatation/blunting with cortical scarring
- Micturating cystourethrogram (MCUG) may help to identify reflux.
- Technetium-99m Tc-DMSA scan is the most sensitive for demonstration of renal
scars.

Management
• Aim to investigate and treat any infection, prevent further UTI, and monitor and
optimize renal function
• Blood pressure should be controlled to slow the progression of chronic kidney
disease. Ideally using angiotensin-converting enzyme (ACE) inhibitors
• Severe underlying VUR diagnosed in children may require antibiotics
prophylactically until puberty or until the reflux resolves

Q-31
A 58 year old man complains of tiredness, lethargy, nausea and severe itching
which is worse after a hot bath and at night. His skin appears pale and dry with
increased skin pigmentation and numerous scratch marks. Peripheral oedema is
noted on examination. What is the SINGLE most likely diagnosis?
A. Hyperthyroidism
B. Polycythaemia vera
C. Chronic renal failure
D. Eczema
E. Liver failure
ANSWER:
Polycythemia vera

EXPLANATION:
The signs and symptoms points towards chronic renal failure. Uraemic pruritus also
known as chronic kidney disease associated pruritus refers to excessive urea in the
blood and occurs when both kidneys fail to work sufficiently. It is a common feature of
end stage renal disease and has been seen to affect one-third of patients on dialysis.

Q-32
A 45 year old known hypertensive man presents with tiredness, lethargy, fluid
retention and proteinuria. His albumin levels are low. What is the SINGLE most
definitive diagnostic test?

A. Mid stream urine for culture

B. Renal biopsy
C. Renal function test
D. Urine microscopy
E. Serum protein

ANSWER:
Renal biopsy

EXPLANATION:
This patient is presenting with nephrotic syndrome. The definitive test to do is a renal
biopsy as this would provide us with the aetiology.

Q-33
A 35 year old woman presents to her general practitioner for a routine medical
check-up. Upon questioning, it was revealed that she has no significant medical
history of note. She is on no chronic medication and has no significant family
history. The patient does not drink alcohol and is extremely careful about her
health. She has had two successful pregnancies carried to term and both her
children are healthy and well. Dipstick urinalysis revealed the presence of 1+
protein. What is the SINGLE most appropriate next step in the management of
this patient?
A. Refer to renal clinic
B. Start ACE inhibitors
C. Renal ultrasound
D. Advice to reduce the amount of protein in her diet
E. Repeat the test

ANSWER:
Repeat the test

EXPLANATION:
A dipstick analysis is the most common test in the outpatient setting to evaluate the
urine protein concentration as well as other markers of renal disease. It is important to
note that dipstick proteinuria has a prevalence of around 5% in healthy individuals which
is usually a trace to 1+ range. Urine dipsticks also may have a false positive result.
Events in which a false positive can occur on urinalysis include alkaline urine, if the
dipstick is immersed too long, with highly concentrated urine, or in the presence of pus,
semen or vaginal secretions. Remember as well that an important cause of transient
proteinuria is exercise. This patient is a gym instructor and, as such, would be
exercising a lot. Since this patient is otherwise healthy and has no outward indicator of
having renal disease, the most approprate next step for this patient would be to repeat
the urine dipstick test. If the urinalysis still shows proteinuria, the next step after that
would be to do a 24 hour urine specimen test or urine protein creatinine ratio.

When do you refer a patient to the renal clinic?

The Renal Association of the United Kingdom has published guidelines on when it is
appropriate to refer to a renal specialist. You should never refer isolated proteinuria
without investigating further.
Advising this patient to reduce the amount of protein in her diet is the blatantly wrong
chioce here. A diet low in protein may be advised for those who have chronic kidney
disease but since there is no indication that this patient has any form of kidney disease,
this answer is incorrect.

Q-34
A 35 year old lady presents with a 12 day history of haemoptysis, and 24 hour
history of haematuria. In last 24 hours she has become increasingly breathless
and oliguric. A chest X-ray shows patchy interstitial infiltration predominantly
affecting both lower zones. Her blood tests show:
Haemoglobin 98 g/L
Serum urea 9.5 mmol/L
Serum creatinine 393 micromol/L
Sodium 136 mmol/L
Potassium 5.9 mmol/L
What is the SINGLE most appropriate investigation?

A. Anti-glomerular basement membrane antibodies

B. Abdominal X-ray
C. Urine protein electrophoresis
D. Ultrasound abdomen
E. Computed tomography abdomen and chest
ANSWER:
Anti-glomerular basement membrane antibodies

EXPLANATION:
The likely diagnosis here is Goodpasture syndrome. The blood reflect an acute kidney
injury. The slightly lower haemoglobin levels can be explained by the persistent
intrapulmonary bleeding.

Anti-GBM antibodies are diagnostic.

Goodpasture syndrome
- Goodpasture's syndrome is the coexistence of acute glomerulonephritis and
pulmonary alveolar haemorrhage
Presentation
• Typically presents as acute kidney injury caused by a rapidly progressive
glomerulonephritis, accompanied by pulmonary haemorrhage that may be
lifethreatening
• Lung involvement is characterized by haemoptysis, cough, and shortness of breath

Anti-glomerular basement membrane antibodies antibodies are diagnostic

Remember: The best initial test to confirm the diagnosis is anti-GBM antibodies. The
SINGLE most accurate test is a lung or kidney biopsy

Management
Management for Goodpasture syndrome is highly unlikely to be asked given that
Goodpasture's syndrome is an uncommon disease. But one should remember the
principles of management:
- Plasmapheresis (plasma exchange) to remove circulating antibodies
- Treat with immunosuppressant medications to prevent further production of antibodies

Q-35
A 4 year old child presents with swelling. Periorbital oedema, lower limb oedema
and oedema of the genitals were noted on examination. A urine dipstick shows
proteinuria. He has a normal renal function, normal blood pressure, normal
complement levels. What is the SINGLE most likely diagnosis?

A. Post-streptococcal glomerulonephritis
B. Membranous glomerulonephropathy
C. Minimal change disease
D. Rapidly progressive glomerulonephritis
E. IgA nephropathy

ANSWER:
Minimal change disease

EXPLANATION:
Please see Q-23

Q-36
A 65 year old woman with diabetes, and hypertension underwent a total right hip
replacement. She had massive haemorrhage during the operation and was given
8 units of packed red blood cells. The blood pressure dropped to 60/40 mmHg for
about two hours before it was corrected with intravenous fluids and blood
transfusions. Two days after the surgery, her blood results show:

Serum creatinine level rose to 255 micromol/L

Potassium 5.1 mmol/L

She had a normal kidney function prior to the surgery. What is the SINGLE most
likely diagnosis?
 A. Diabetic nephropathy
B. Malignant hypertension
C. Rhabdomyolysis
D. Interstitial nephritis
E. Acute tubular necrosis

ANSWER:
Acute tubular necrosis

EXPLANATION:
Acute tubular necrosis (ATN) can occur after a prolonged ischaemic event which likely
took place here as there was a massive haemorrhage and a hypotensive shock. This is
supported by the increased creatinine.

Acute tubular necrosis is the commonest renal cause of an acute kidney injury. Other
stems may include a history of nephrotoxins such as aminoglycosides, radiological
contrast, and myoglobinuria in rhabdomyolysis.

Q-37
A 42 year old woman with a past medical history of severe headache treated in
the emergency department presents with signs and symptoms of renal failure.
She has been seen by her GP for hypertension and loin pain with outpatient
investigation pending. What SINGLE investigation is most likely to lead to a
diagnosis?

A. Ultrasound of the kidneys, ureter and bladder

B. Computed tomography brain scan
C. Intravenous urogram
D. Renal artery doppler
E. Renal biopsy

ANSWER:
Ultrasound of the kidneys, ureters & bladder

EXPLANATION:
The initial symptoms of headache and hypertension in this scenario would make you
consider a renal artery stenosis. However, in addition to the loin pain and features of
renal failure, the diagnosis of autosomal dominant polycystic kidney disease is more
likely. This is best diagnosed using ultrasound of the kidneys, ureters & bladder.

Questions often ask about screening test for PKD and give you an option between
genetic testing for PKD1 or an ultrasound scan. The answer should always be an
ultrasound scan. Genetic testing for PKD1 is difficult as the gene is large and there are
hundreds of described mutations. USS screening offers good sensitivity and specificity.

Autosomal dominant polycystic kidney disease

Presentation
- Flank pain
- Haematuria (micro and gross)
- Urinary tract infections (UTIs) and calculi
- Hypertension
- Bilateral kidney enlargement - abdominal examination may reveal enlarged and
palpable kidneys

Other points:
- Gross haematuria following trauma is a classic presenting feature of ADPKD
- Sometimes present with kidney failure (usually in the fourth to sixth decade of life)
- May also present as asymptomatic on screening of family members
- Intracranial aneurysm is an important extrarenal manifestation (an important point that
is commonly asked)

Note: The other extra-renal manifestation are less commonly asked

Diagnosis:
Ultrasound

Treatment
Nonspecific; management of hypertension

Q-38
A 45 year old man with renal cell carcinoma recently underwent a left
nephrectomy two weeks ago. He presents feeling unwell with a temperature of
38.3°C and he has not been able to pass urine for a day. An ultrasound scan was
performed which shows a 9 mm stone in the right lower ureter with dilatation of
the pelvicaliceal system. What is the SINGLE best initial management for this
man?

A. Catheter
B. Percutaneous nephrostomy
C. Lithotripsy
D. Intravenous fluids
E. Diuretics

ANSWER:
Percutaneous nephrostomy

EXPLANATION:
The patient has a single function kidney and an obstructive uropathy. It is imperative to
prevent damage to the remaining kidney by performing a percutaneous nephrostomy to
temporarily decompress the renal collecting system.

Q-39
A 31 year old woman has urinary frequency, pain on voiding and back pain. Her
urine is cloudy with an offensive smell. She has a temperature of 38.6 C. Her
urinalysis showed leukocytes 2+ and nitrates +. Her midstream urine sample was
sent off for microscopy and culture. What is the SINGLE most likely causative
organism?
 A. Klebsiella
B. Eschericia coli
C. Proteus mirabilis
D. Staphylococci
E. Pseudomonas aeruginosa

ANSWER:
Eschericia coli

EXPLANATION:
The patient has a urinary tract infection. She displays lower urinary tract symptoms
(urinary frequency, pain on voiding) and symptoms of pyelonephritis (back pain and
fever). Eschericia coli causes around 80% of urinary tract infections.

Q-40
A 57 year old male presents to Accident & Emergency with the complaint of
weakness and confusion. His wife, who accompanies him, gives a history of her
husband first complaining of a loss of sensation in his fingers and muscle
cramps which has now deteriorated to this. The patient’s past medical history is
significant for chronic kidney disease stage 4, diagnosed two years ago and non-
insulin dependent diabetes mellitus which was diagnosed seven years ago. He
currently takes metformin and enalapril. Blood tests were carried out and the
results are as follows:

Sodium 138 mmol/L (135-145 mmol/L)

Potassium 5.9 mmol/L (3.5-5.0 mmol/L)
Calcium (Total) 1.8 mmol/L (2.1-2.6 mmol/L)
Phosphate 2.9 mmol/L (0.8-1.4 mmol/L)
Parathyroid hormone (PTH) 4.2 pmol/L (0.8-8.5 pmol/L)
Alkaline phosphatase (ALP) 45 U/L (30-150 U/L)

What is the SINGLE most likely cause that can account for the patient’s
presentation?

A. Hyperphosphataemia
B. 1, 25 dihydroxyvitamin D3 deficiency
C. Acidosis
D. Hyperparathyroidism
E. Hypernatraemia
ANSWER:
1, 25 dihydroxyvitamin D3 deficiency

EXPLANATION:
His symptoms are the result of hypocalcaemia. Unfortunately, hypocalcaemia is not in
one of the options as that would be too easy. The patient has chronic kidney disease
(CKD) which may have resulted from the years of having poor glycaemic control leading
to diabetic nephropathy. Chronic kidney disease results in decrease in the conversion
of 25-hydroxyvitamin D to its active form 1, 25 dihydroxyvitamin D, especially when the
glomerular filtration rate (GFR) falls below 30 mL/min. This results in low calcium
abosrption which also increases parathyroid hormone.
Even though this patient has hyperphosphataemia as clearly seen by the given lab
results, it is not the correct answer because an isolated increase in serum phosphate
lvel rarely presents with any outward signs or symptoms.