7.
2 Chronic kidney disease 295
Approach to rhabdomyolysis
The diagnosis is usually made on clinical grounds.
Symptoms include:
1
•• Haematuria on urinalysis
•• Hyperkalaemia, hypocalcaemia and
hyperphosphataemia 2
•• CK is significantly elevated, up to 5 times baseline
Treatment involves aggressive fluid therapy and
correction of electrolyte abnormalities, particularly if 3
hyperkalaemia or hypocalcaemia are life-threatening.
P Statins carry a very small risk of 4
rhabdomyolysis (<1%).
Fig. 7.4 Reddish-brown urine of a patient with
rhabdomyolysis. 6
7.2 Chronic kidney disease 7
Definition: chronic kidney disease refers to kidney Classifying persistent albuminuria:
damage for 3 or more months, secondary to structural •• Mild <30mg/g
or functional disorders or disease that presents with •• Moderate 30–300mg/g 8
an estimated glomerular filtration rate (eGFR) <60ml/ •• Severe >300mg/g
min/1.73m2 on two separate occasions.
Chronic kidney disease in adults: E Note that in patients with extreme 9
amounts of muscle mass (e.g. bodybuilders)
assessment and management
eGFR results should be interpreted with
(NICE 2014, CG182) caution. 10
Table 7.1 Classification of CKD according to eGFR
Stage Severity eGFR Epidemiology:
1 Normal/high ≥90
•• Incidence has increased 11
•• Affects almost 10% of adults worldwide
2 Mild reduction 60–89 •• Commonly seen in older patients with long-
standing DM or hypertension
3a Mild/moderate 45–59 •• Afro-Caribbean and Asian populations are at 12
3b Moderate/severe 30–44 greater risk
Aetiology/pathophysiology:
13
4 Severe 15–29
5 Kidney failure ≤15 Table 7.2 Causes of CKD
Common causes Other causes
NICE advises that an increased ACR and a decreased
•• Diabetes mellitus •• Renovascular disease
14
GFR are associated with an increased risk of poorer
outcomes, and this risk is multiplied if increased ACR •• Hypertension •• GN, SLE
and decreased GFR occur together. •• Interstitial disease (often
drug-induced) 15
Bear in mind that the KDIGO guidelines also include •• Polycystic kidney disease
the degree of albuminuria (which also reflects kidney
disease and mortality) in their stratification of CKD.
296 Chapter 7: Nephrology
2 Manage cardiovascular disease
P Patients are said to have accelerated •• Optimise risk factors, prescribe statins and
1 progression of disease if there is a change in antiplatelet agents as appropriate
GFR category or a sustained decrease in GFR •• Consider the use of apixaban instead of
of ≥25% within 12 months or <15ml/min/1.73m2 warfarin, if patients have AF and Stage 3b CKD
2 per year. or if they have a history of DM, heart failure, or
previous cerebrovascular events
Clinical features: 3 Check for renal bone disease and
3 •• Patients may be asymptomatic until a late stage electrolyte abnormalities
•• Symptoms classically associated with CKD (such •• Measure calcium, phosphate, PTH and Vit D
as pruritus, polyuria, oedema, fatigue and muscle levels if eGFR <30ml/min/1.73m2
•• Attempt to normalise calcium and phosphate
4 weakness) largely occur in severe CKD
•• Patients with CKD typically have other comorbid levels
conditions as well, e.g. coronary artery disease, •• Offer bisphosphonates, as appropriate, for
hypertension, dyslipidaemia, and mineral and prevention and treatment of osteoporosis
5 bone disorders •• KDIGO guidelines recommend alkali
supplementation (e.g. sodium bicarbonate) to
Investigations keep serum bicarbonate in the normal range,
as lower levels of bicarbonate have been
6 Stepwise plan (NICE 2014, CG182): associated with poorer outcomes
1 Assess kidney function 4 Manage anaemia
•• Measure eGFR •• Screen and correct for iron deficiency
7 •• Advise patients to abstain from eating meat •• Offer erythropoietic-stimulating agent as
12 hours before eGFR measurement appropriate
•• Urine ACR >3mg/mmol
5 Manage oedema
8 2 Arrange blood tests and urine dipstick •• Offer loop diuretic (e.g. furosemide 40mg) as
•• Normochromic normocytic anaemia appropriate
•• Auto-antibody testing if underlying disease
6 Provide renal replacement therapy
9 is suspected
•• This is recommended for end-stage disease
3 Obtain renal ultrasound
•• Offer if patients have:
–– Symptoms of obstruction
W Renal osteodystrophy refers to a disorder
10 –– Accelerated progression of disease in bone mineralisation secondary to chronic
–– Family history of polycystic kidney disease kidney disease. This occurs because a reduced
–– Visible or persistent microscopic ability to excrete phosphate develops as CKD
11 haematuria progresses, leading to hyperphosphataemia
and secondary hyperparathyroidism. As
Management 1-Alpha hydroxylation of vitamin D is carried
Educate patients about their condition, and out by the kidneys, there is an impaired
12 encourage them to stop smoking and adjust their conversion of vitamin D to its active form,
calorie, potassium, phosphate and salt intake. leading to decreased uptake of calcium in the
Low-protein diets are not recommended, as there small intestine.
13 is insufficient evidence to recommend their use at
present. Nephrotoxic medications should be withheld.
E Elevated PTH levels cause osteoclastic
Stepwise management of chronic kidney breakdown of bone and predisposition to
14 disease (NICE 2014, CG182) osteoporosis or osteomalacia. Treatment of
renal osteodystrophy involves phosphate
1 Manage blood pressure binders, e.g. sevelamer or Calcichew (calcium
15 •• Target: <140/90 carbonate and vit. D3), calcium and vitamin D
•• Target: <130/80 if ACR >70mg/mmol supplementation and/or cinacalcet (a
•• Offer ACE inhibitors first line; stop anti- calcimimetic used to reduce PTH levels in
hypertensives if hyperkalaemia develops secondary hyperparathyroidism).
