Endocrinology

1. Diabetes Mellitus Type 1

Clues in Questions:
• Patient: Child or adolescent presenting with polyuria, polydipsia, weight loss, and fatigue.
• Scenario: A young patient presenting with symptoms of hyperglycemia and possible diabetic ketoacidosis (DKA)
(e.g., fruity breath, Kussmaul breathing).
Diagnosis:
• Initial test:
o Fasting plasma glucose ≥7.0 mmol/L (≥126 mg/dL).
o Random plasma glucose ≥11.1 mmol/L (≥200 mg/dL) with symptoms.
o HbA1c ≥6.5%.
• Other tests: Autoantibodies (e.g., anti-GAD, anti-IA2) to confirm Type 1 DM.
Management:
• First-line treatment: Insulin therapy (basal-bolus regimen or continuous insulin infusion).
• DKA management:
o IV insulin.
o Fluid resuscitation with isotonic saline.
o Potassium supplementation as insulin therapy may cause hypokalemia.
Contraindications:
• Avoid using oral hypoglycemic agents (e.g., sulfonylureas) in Type 1 DM, as these are ineffective due to absolute
insulin deficiency.
• In DKA, avoid rapid correction of hyperglycemia, as this can lead to cerebral edema, especially in pediatric patients.

2. Diabetes Mellitus Type 2

Clues in Questions:
• Patient: Overweight or obese adult with polydipsia, polyuria, and blurred vision.
• Scenario: Middle-aged patient with high BMI, acanthosis nigricans, and symptoms of hyperglycemia or
asymptomatic hyperglycemia found on routine screening.
Diagnosis:
• Initial test:
o Fasting plasma glucose ≥7.0 mmol/L (≥126 mg/dL).
o HbA1c ≥6.5%.
• Other tests: Lipid panel, renal function, and urine microalbumin to assess for complications.
Management:
• First-line treatment:
o Lifestyle modifications (diet, exercise).
o Metformin as the preferred initial pharmacologic therapy.
• Second-line treatment: SGLT2 inhibitors, GLP-1 receptor agonists, or DPP-4 inhibitors depending on patient
comorbidities.
• Insulin therapy: Consider in cases of severe hyperglycemia or failure of oral agents.
Contraindications:
• Avoid Metformin in patients with eGFR <30 mL/min/1.73 m² due to the risk of lactic acidosis.
• Avoid SGLT2 inhibitors in patients with recurrent UTIs or genital mycotic infections, as they increase the risk of
infections in the genital tract.
• Sulfonylureas should be used cautiously in patients prone to hypoglycemia, particularly the elderly or those with
renal impairment.

3. Diabetic Ketoacidosis (DKA)

Clues in Questions:
• Patient: Type 1 diabetic with nausea, vomiting, abdominal pain, fruity breath, polyuria, and dehydration.
• Scenario: Diabetic patient presenting with confusion, tachycardia, Kussmaul respirations, and signs of dehydration.
Diagnosis:
• Initial test:
o Plasma glucose >13.9 mmol/L (>250 mg/dL).
o Serum ketones or β-hydroxybutyrate.
o Anion gap metabolic acidosis (arterial pH <7.3, HCO₃⁻ <15 mEq/L).
• Other tests: Serum electrolytes, blood gases, urinalysis for ketones.
Management:
• First-line treatment:
o IV fluids (normal saline initially, then switch to D5 half-normal saline when glucose <250 mg/dL).
o IV insulin infusion until ketosis resolves.
o Electrolyte replacement (e.g., potassium even if K⁺ is initially normal or low).
Contraindications:
• Avoid rapid correction of hyperglycemia, which may cause cerebral edema, especially in pediatric patients.
• Avoid insulin therapy without ensuring adequate potassium levels (K⁺ <3.3 mEq/L), as insulin drives potassium into
cells and can precipitate hypokalemia.
• Bicarbonate therapy is generally avoided unless the pH is <6.9, as it can worsen hypokalemia and delay correction
of ketosis.

4. Hyperosmolar Hyperglycemic State (HHS)

Clues in Questions:
• Patient: Elderly patient with poorly controlled Type 2 diabetes, presenting with extreme hyperglycemia,
dehydration, altered mental status, but no significant ketosis.
• Scenario: Diabetic patient with symptoms of profound dehydration, confusion, and serum glucose >33.3 mmol/L
(>600 mg/dL).
Diagnosis:
• Initial test:
o Plasma glucose >33.3 mmol/L (>600 mg/dL).
o Serum osmolality >320 mOsm/kg.
o Minimal or no ketones.
o pH >7.3 and HCO₃⁻ >18 mEq/L.
• Other tests: Electrolytes, blood gases, urinalysis.
Management:
• First-line treatment:
o IV fluids (initially isotonic saline).
o IV insulin (after adequate fluid resuscitation).
o Electrolyte management (particularly potassium).
Contraindications:
• Avoid rapid correction of serum glucose and sodium, as this may cause cerebral edema.
• Avoid insulin administration without sufficient fluid resuscitation, as this can worsen hypovolemia.
• Be cautious with diuretics in HHS, as patients are already profoundly dehydrated.

5. Hypothyroidism
Clues in Questions:
• Patient: Adult with fatigue, weight gain, cold intolerance, constipation, and dry skin.
• Scenario: Patient presenting with symptoms of slowed metabolism, bradycardia, and delayed reflexes.
Diagnosis:
• Initial test:
o Elevated TSH with low free T4 (primary hypothyroidism).
• Other tests: Anti-TPO antibodies to diagnose Hashimoto’s thyroiditis.
Management:
• First-line treatment: Levothyroxine (synthetic T4).
o Adjust dose based on TSH levels (goal: normalize TSH).
Contraindications:
• Avoid overtreatment with Levothyroxine, especially in elderly patients, as this can lead to atrial fibrillation and
osteoporosis.
• In patients with adrenal insufficiency, correct this before initiating levothyroxine to avoid adrenal crisis.
• Avoid abrupt dose changes in pregnancy, as hypothyroidism needs closer monitoring due to the increased demand
for thyroid hormone.

6. Hyperthyroidism (Graves' Disease)

Clues in Questions:
• Patient: Adult with weight loss, heat intolerance, tremor, palpitations, and exophthalmos.
• Scenario: Patient presenting with symptoms of thyrotoxicosis (e.g., weight loss, tachycardia) and enlarged thyroid.
Diagnosis:
• Initial test:
o Low TSH, elevated free T4 and/or T3.
• Other tests:
o Thyroid-stimulating immunoglobulins (TSI) to confirm Graves' disease.
o Radioactive iodine uptake (RAIU) to differentiate causes of hyperthyroidism.
Management:
• First-line treatment:
o Methimazole or Propylthiouracil (PTU) to block thyroid hormone synthesis.
o Beta-blockers (e.g., Propranolol) for symptom control.
• Definitive therapy: Radioactive iodine ablation or thyroidectomy in refractory cases.
Contraindications:
• Avoid Methimazole in the first trimester of pregnancy due to teratogenic effects; PTU is preferred during early
pregnancy.
• Avoid radioactive iodine therapy in pregnant or breastfeeding women.
• Use caution with radioactive iodine in patients with ophthalmopathy, as it can worsen eye symptoms; steroid
prophylaxis may be needed.

7. Thyroid Storm
Clues in Questions:
• Patient: Known or suspected hyperthyroid patient presenting with fever, tachycardia, delirium, agitation, or coma.
• Scenario: Patient with a history of Graves' disease or untreated hyperthyroidism presenting with acute
decompensation following stress (e.g., surgery, infection).
Diagnosis:
• Initial test: Clinical diagnosis based on severe thyrotoxicosis (e.g., hyperpyrexia, tachycardia, altered mental status).
• Other tests: TSH, free T4/T3 (usually markedly elevated).
Management:
• First-line treatment:
o Beta-blockers (e.g., Propranolol) to control heart rate.
o Antithyroid drugs (e.g., PTU to block new hormone synthesis).
 o Iodine (after PTU) to block hormone release.
o Steroids to prevent peripheral conversion of T4 to T3.
• Supportive care: Cooling, IV fluids, treatment of precipitating cause (e.g., infection).
Contraindications:
• Avoid Methimazole in thyroid storm, as PTU is preferred due to its additional effect of inhibiting peripheral
conversion of T4 to T3.
• Avoid delaying treatment, as thyroid storm is a life-threatening condition with high mortality if not managed
aggressively.

8. Primary Hyperparathyroidism
Clues in Questions:
• Patient: Middle-aged or older adult presenting with bone pain, fractures, kidney stones, abdominal pain, and
depression.
• Scenario: A patient with hypercalcemia and symptoms related to "stones, bones, groans, and psychiatric
overtones".
Diagnosis:
• Initial test:
o Elevated serum calcium with elevated PTH.
• Other tests: 24-hour urine calcium to differentiate from familial hypocalciuric hypercalcemia.
Management:
• First-line treatment: Parathyroidectomy for symptomatic patients or those with complications (e.g., osteoporosis,
kidney stones).
• Medical management:
o Bisphosphonates or Cinacalcet for patients who are not surgical candidates.
o Hydration to prevent kidney stones.
Contraindications:
• Avoid delaying surgical intervention in symptomatic patients, as untreated hyperparathyroidism can lead to
osteoporosis and renal damage.
• Be cautious using thiazide diuretics in hyperparathyroidism, as they can increase calcium reabsorption and
exacerbate hypercalcemia.

9. Addison’s Disease (Primary Adrenal Insufficiency)

Clues in Questions:
• Patient: Adult with fatigue, weight loss, hyperpigmentation, hypotension, and salt craving.
• Scenario: A patient presenting with chronic fatigue, orthostatic hypotension, and hyperkalemia.
Diagnosis:
• Initial test:
o Low cortisol with high ACTH (primary adrenal insufficiency).
• Other tests:
o ACTH stimulation test (cortisol fails to rise in response to ACTH).
o Electrolytes (hyponatremia, hyperkalemia).
Management:
• First-line treatment: Glucocorticoid replacement (e.g., Hydrocortisone) and mineralocorticoid replacement (e.g.,
Fludrocortisone) for primary adrenal insufficiency.
Contraindications:
• Avoid delaying steroid replacement, as untreated adrenal insufficiency can lead to an adrenal crisis, which is life-
threatening.
• Use caution in patients with active infections, as glucocorticoid therapy can suppress the immune response.
10. Cushing’s Syndrome (Hypercortisolism)
Clues in Questions:
• Patient: Adult with weight gain, central obesity, moon facies, purple striae, muscle weakness, and hypertension.
• Scenario: A patient presenting with features of cortisol excess, such as easy bruising, proximal muscle weakness,
and hirsutism.
Diagnosis:
• Initial test:
o 24-hour urinary free cortisol (elevated).
o Low-dose dexamethasone suppression test (no suppression of cortisol).
• Other tests: ACTH levels to differentiate between ACTH-dependent (e.g., Cushing's disease, ectopic ACTH) and
ACTH-independent (e.g., adrenal adenoma) causes.
Management:
• First-line treatment:
o Surgical resection of the underlying cause (e.g., pituitary adenoma, adrenal tumor).
o Ketoconazole or Metyrapone to reduce cortisol production in cases where surgery is delayed or not
possible.
Contraindications:
• Avoid long-term glucocorticoid use, as this is the most common cause of exogenous Cushing's syndrome. Careful
tapering of steroids is required to avoid adrenal insufficiency.
• In patients with adrenal adenomas, avoid delaying surgical resection, as untreated Cushing’s syndrome can lead to
complications such as diabetes, osteoporosis, and hypertension.

11. Pheochromocytoma
Clues in Questions:
• Patient: Adult presenting with paroxysmal episodes of headache, palpitations, sweating, and hypertension.
• Scenario: A patient with episodic hypertension and symptoms of sympathetic overactivity (e.g., tachycardia,
diaphoresis).
Diagnosis:
• Initial test:
o 24-hour urinary metanephrines or plasma free metanephrines (elevated).
• Other tests:
o CT/MRI of the abdomen to localize the tumor.
o MIBG scan if there is suspicion of metastatic or extra-adrenal pheochromocytoma.
Management:
• First-line treatment:
o Alpha-blockade (e.g., Phenoxybenzamine) to control hypertension.
o Beta-blockers after adequate alpha-blockade to control tachycardia.
o Surgical resection of the tumor is the definitive treatment.
Contraindications:
• Avoid beta-blockers alone without prior alpha-blockade, as unopposed alpha stimulation can worsen hypertension.
• Avoid delaying surgery once the tumor is adequately blocked, as untreated pheochromocytomas can lead to
hypertensive crises and life-threatening complications.

12. Hyperaldosteronism (Conn’s Syndrome)

Clues in Questions:
• Patient: Adult with hypertension, hypokalemia, muscle cramps, and fatigue.
• Scenario: A hypertensive patient with unexplained hypokalemia and metabolic alkalosis, despite not being on
diuretics.
Diagnosis:
 • Initial test:
o Plasma aldosterone-to-renin ratio (elevated aldosterone, suppressed renin).
• Accurate test:
o Adrenal CT to locate an adrenal adenoma.
o Adrenal vein sampling to differentiate unilateral from bilateral disease.
Management:
• First-line treatment:
o Unilateral adrenal adenoma: Surgical resection.
o Bilateral adrenal hyperplasia: Spironolactone or Eplerenone (aldosterone antagonists).
Contraindications:
• Avoid unnecessary diuretic use in patients with primary hyperaldosteronism, as this can exacerbate hypokalemia.
• In patients with bilateral adrenal hyperplasia, avoid surgery, as it is only indicated for unilateral causes.

13. Hypocalcemia
Clues in Questions:
• Patient: Adult or child with muscle cramps, tetany, paresthesias, and a history of thyroid or parathyroid surgery.
• Scenario: A patient presenting with Chvostek's sign, Trousseau's sign, and symptoms of hypocalcemia (e.g.,
perioral numbness, muscle cramps).
Diagnosis:
• Initial test:
o Low serum calcium with elevated phosphate and low PTH (primary hypoparathyroidism).
• Other tests:
o Vitamin D levels (to assess for vitamin D deficiency).
o Magnesium levels (hypomagnesemia can contribute to hypocalcemia).
Management:
• First-line treatment:
o Calcium supplementation (oral or IV depending on severity).
o Vitamin D supplementation (e.g., calcitriol) for long-term management in chronic hypoparathyroidism.
Contraindications:
• Avoid delayed calcium replacement, especially in patients with acute symptomatic hypocalcemia, as this can lead
to seizures or cardiac arrhythmias.
• In patients with renal failure, avoid high-dose calcium supplementation without monitoring, as it can lead to
hyperphosphatemia and vascular calcifications.

14. Hypercalcemia (Primary Hyperparathyroidism or Malignancy-Related)

Clues in Questions:
• Patient: Adult with polyuria, constipation, bone pain, kidney stones, and mental status changes.
• Scenario: A patient presenting with hypercalcemia and related symptoms (e.g., "stones, bones, moans, and
groans").
Diagnosis:
• Initial test:
o Elevated serum calcium.
o PTH level: Elevated in primary hyperparathyroidism, low in malignancy-related hypercalcemia.
• Other tests:
o Chest X-ray or serum protein electrophoresis to rule out malignancy.
o 24-hour urine calcium to differentiate from familial hypocalciuric hypercalcemia.
Management:
• First-line treatment:
 o IV fluids and bisphosphonates for symptomatic hypercalcemia.
o Calcitonin for rapid calcium reduction in severe cases.
o Surgical resection for parathyroid adenoma (primary hyperparathyroidism).
Contraindications:
• Avoid thiazide diuretics in hypercalcemia, as they increase calcium reabsorption and worsen the condition.
• In patients with malignancy-related hypercalcemia, avoid delaying treatment with bisphosphonates, as rapid
calcium reduction is needed to prevent cardiac arrhythmias and coma.

15. Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)

Clues in Questions:
• Patient: Adult presenting with hyponatremia, nausea, headache, confusion, and a history of lung disease (e.g.,
small cell lung cancer).
• Scenario: A patient with euvolemic hyponatremia and low serum osmolality, often with a history of malignancy or
CNS trauma.
Diagnosis:
• Initial test:
o Low serum sodium (<135 mmol/L).
o Low serum osmolality with high urine osmolality and elevated urine sodium.
• Other tests:
o Chest X-ray to look for underlying malignancy.
o CT/MRI of the brain if CNS cause is suspected.
Management:
• First-line treatment:
o Fluid restriction.
o IV hypertonic saline for severe hyponatremia (e.g., seizures).
o Demeclocycline or vasopressin receptor antagonists (e.g., Tolvaptan) for chronic management.
Contraindications:
• Avoid rapid correction of hyponatremia, as this can lead to osmotic demyelination syndrome (central pontine
myelinolysis).
• Be cautious using loop diuretics in patients with SIADH, as they can cause further electrolyte imbalances.

16. Diabetes Insipidus (DI)

Clues in Questions:
• Patient: Adult presenting with polyuria, polydipsia, and hypernatremia following head trauma or pituitary surgery.
• Scenario: A patient with excessive thirst, high-volume dilute urine output, and hypernatremia, with a history of CNS
disease or trauma.
Diagnosis:
• Initial test:
o Water deprivation test showing inability to concentrate urine (continued dilute urine).
• Other tests:
o Serum sodium (elevated) and serum osmolality (elevated).
o Desmopressin (ADH) challenge to differentiate between central and nephrogenic DI.
Management:
• First-line treatment:
o Central DI: Desmopressin (DDAVP).
o Nephrogenic DI: Thiazide diuretics, indomethacin, or amiloride.
Contraindications:
 • Avoid delayed administration of desmopressin in central DI, as untreated DI can lead to severe dehydration and
hypernatremia.
• In patients with nephrogenic DI, avoid NSAIDs in those with compromised kidney function, as they may worsen
renal disease.

17. Adrenal Crisis

Clues in Questions:
• Patient: Known patient with Addison’s disease or chronic glucocorticoid use presenting with shock, hypotension,
vomiting, abdominal pain, and fever.
• Scenario: A patient with a history of adrenal insufficiency presenting with acute hypotension, dehydration, and
altered mental status following a stressor (e.g., infection, surgery).
Diagnosis:
• Initial test:
o Clinical diagnosis based on acute hypotension, hyponatremia, and hyperkalemia.
• Other tests:
o Serum cortisol (low), ACTH (high in primary adrenal insufficiency).
Management:
• First-line treatment:
o IV fluids (normal saline).
o IV hydrocortisone or dexamethasone immediately.
o Correct electrolyte imbalances (e.g., hypoglycemia, hyperkalemia).
Contraindications:
• Avoid delaying steroid replacement, as adrenal crisis can lead to shock and death if not treated promptly.
• Use caution with vasopressors in adrenal crisis; they may not be effective until cortisol levels are corrected.
18. Hyperkalemia
Clues in Questions:
• Patient: Adult with renal failure, on potassium-sparing diuretics, ACE inhibitors, or with adrenal insufficiency,
presenting with muscle weakness, fatigue, or palpitations.
• Scenario: A patient with chronic kidney disease, heart failure, or adrenal insufficiency, presenting with symptoms
of weakness, paresthesias, and arrhythmias.
Diagnosis:
• Initial test:
o Serum potassium >5.5 mmol/L.
o ECG changes: Peaked T waves, prolonged PR interval, widened QRS, sine wave pattern in severe cases.
• Other tests:
o Serum creatinine to assess kidney function.
o Urine potassium and aldosterone levels to assess renal and adrenal function.
Management:
• First-line treatment (for ECG changes or severe hyperkalemia):
o Calcium gluconate (to stabilize cardiac membrane).
o Insulin with glucose (to drive potassium into cells).
o Beta-agonists (e.g., albuterol) to shift potassium intracellularly.
o Sodium bicarbonate (in metabolic acidosis).
o Loop diuretics (e.g., furosemide) to promote potassium excretion if renal function allows.
o Hemodialysis in patients with severe renal impairment or refractory hyperkalemia.
• Chronic management: Potassium binders (e.g., patiromer, sodium polystyrene sulfonate) for patients with chronic
hyperkalemia.
Contraindications:
 • Avoid calcium administration in patients taking digitalis (digoxin), as it can precipitate digoxin toxicity and worsen
cardiac arrhythmias.
• Avoid using potassium-sparing diuretics (e.g., spironolactone, eplerenone) in patients with severe hyperkalemia,
as they may further increase serum potassium.
• Be cautious with ACE inhibitors and ARBs in patients with renal failure or hyperkalemia, as they reduce aldosterone
secretion and impair potassium excretion.

19. Hypokalemia
Clues in Questions:
• Patient: Adult or child with a history of diarrhea, vomiting, diuretic use (especially loop diuretics or thiazides), or
hyperaldosteronism, presenting with muscle weakness, cramps, or arrhythmias.
• Scenario: A patient presenting with muscle cramps, fatigue, constipation, and flattened T waves on ECG, with a
history of diuretic use or gastrointestinal losses.
Diagnosis:
• Initial test:
o Serum potassium <3.5 mmol/L.
o ECG changes: Flattened T waves, U waves, ST depression, prolonged QT interval.
• Other tests:
o Serum magnesium (hypomagnesemia can exacerbate hypokalemia).
o Urine potassium to assess renal losses (high in renal causes, low in non-renal causes).
o Arterial blood gas to assess for metabolic alkalosis (often seen in hypokalemia due to vomiting or diuretics).
Management:
• First-line treatment:
o Oral potassium chloride for mild-to-moderate hypokalemia.
o IV potassium chloride for severe hypokalemia or symptomatic patients (e.g., arrhythmias, muscle
weakness). Administer slowly to avoid rapid infusion risks.
o Magnesium replacement if concurrent hypomagnesemia is present.
Contraindications:
• Avoid IV potassium bolus administration or rapid infusion rates (>10 mEq/hr) as this can lead to cardiac
arrhythmias or cardiac arrest.
• Be cautious with potassium supplementation in patients with renal impairment due to the risk of inducing
hyperkalemia.
• Avoid diuretics that can worsen potassium loss (e.g., loop or thiazide diuretics) in patients with ongoing
hypokalemia. Consider potassium-sparing diuretics (e.g., spironolactone) for these patients.

20. Hypernatremia
Clues in Questions:
• Patient: Adult or elderly patient with dehydration, diabetes insipidus, or inadequate water intake, presenting with
lethargy, confusion, or seizures.
• Scenario: A patient with hypernatremia and signs of dehydration, often with a history of diabetes insipidus,
excessive diuretic use, or inability to access water.
Diagnosis:
• Initial test:
o Serum sodium >145 mmol/L.
• Other tests:
o Urine osmolality to differentiate between causes (high in extrarenal losses, low in diabetes insipidus).
o Water deprivation test and desmopressin challenge to confirm diabetes insipidus (central vs nephrogenic).
Management:
• First-line treatment:
 o Oral or IV fluids with isotonic saline to correct volume depletion.
o Hypotonic fluids (e.g., 5% dextrose in water or 0.45% saline) for slow correction of hypernatremia once
volume is restored.
o Desmopressin (DDAVP) for central diabetes insipidus.
Contraindications:
• Avoid rapid correction of hypernatremia, as this can lead to cerebral edema and herniation. The goal is to lower
serum sodium by no more than 8-10 mmol/L per day.
• In patients with diabetes insipidus, avoid delaying desmopressin treatment, as untreated DI can lead to severe
dehydration and hypernatremia.

21. Hyponatremia
Clues in Questions:
• Patient: Elderly or hospitalized patient on diuretics, or with conditions such as heart failure, SIADH, or liver
cirrhosis, presenting with lethargy, headache, or seizures.
• Scenario: A patient with altered mental status, lethargy, and symptoms of hyponatremia (e.g., nausea, confusion).
Diagnosis:
• Initial test:
o Serum sodium <135 mmol/L.
• Other tests:
o Serum osmolality and urine osmolality to differentiate causes (e.g., SIADH, volume depletion, heart
failure).
o Urine sodium (high in SIADH, low in hypovolemia).
Management:
• First-line treatment:
o Fluid restriction for SIADH and hypervolemic hyponatremia.
o IV hypertonic saline for severe symptomatic hyponatremia (e.g., seizures, coma).
o Vasopressin antagonists (e.g., tolvaptan) for chronic SIADH.
Contraindications:
• Avoid rapid correction of hyponatremia, as this can lead to osmotic demyelination syndrome (central pontine
myelinolysis). Serum sodium should not increase by more than 8-10 mmol/L per day.
• Avoid using diuretics without electrolyte monitoring in patients with hyponatremia, as this can exacerbate the
condition.