A 20-year-old man presents with recurrent episodes of flaccid weakness of all four limbs. Evaluation reveals normal anion gap metabolic acidosis, serum potassium of 2.2 mEq/L, and urine pH above 6.0. He admits habitually sniffing glue. What is the underlying mechanism of his weakness?
- A Proximal (type 2) renal tubular acidosis with bicarbonaturia
- B Toluene-induced distal (type 1) renal tubular acidosis causing potassium wasting ✓
- C Hypokalemic periodic paralysis from primary familial channelopathy
- D Hyperchloremic acidosis from chronic diarrhoea
Correct answer: B. Toluene-induced distal (type 1) renal tubular acidosis causing potassium wasting
Explanation
Chronic toluene inhalation from glue sniffing causes distal renal tubular acidosis with impaired hydrogen ion secretion, leading to normal anion gap metabolic acidosis, alkaline urine, hypokalemia, nephrocalcinosis, and episodic flaccid paralysis. Proximal RTA would show bicarbonaturia and generalized proximal tubule dysfunction such as glycosuria, which is not described, and glue sniffing points to toluene as the cause rather than a genetic channelopathy.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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