Glucose test triggers paralysis in man with undiagnosed Graves' disease

A 29-year-old man became unable to stand after a routine glucose tolerance test caused a sharp potassium drop, revealing previously undiagnosed overactive thyroid disease.

A routine diabetes screening test turned into a medical emergency for a 29-year-old man in India after a standard glucose drink triggered a rare form of paralysis and exposed previously undiagnosed Graves’ disease, according to a case report published in Clinical Medicine Insights: Case Reports.

The report describes how the man, who had been referred after a workplace check found slightly raised fasting blood sugar, had already been losing weight for weeks despite a strong appetite. He also had palpitations, sweating, heat intolerance, tremor and shakiness after meals, but his thyroid results were not yet available when he was given the 75-gram oral glucose tolerance test. Within about two and a half hours, his potassium level had plunged from 4.1 mmol/L to 1.8 mmol/L and he became too weak to stand.

Doctors said the episode was thyrotoxic periodic paralysis, an uncommon but potentially dangerous complication of an overactive thyroid. The weakness began in the thighs and spread to the shoulders and all four limbs, while sensation, swallowing and breathing remained intact. Blood tests showed that potassium, phosphate and magnesium had all fallen, while insulin surged sharply after the glucose load, a pattern that fits the condition. The authors said the potassium had shifted into muscle cells rather than being lost from the body.

Further testing confirmed Graves’ disease, an autoimmune disorder in which the immune system drives the thyroid to produce too much hormone. The man’s thyroid-stimulating hormone was suppressed and his thyroid hormone levels were high, while antibody testing and ultrasound findings supported the diagnosis. The authors said the case underscores a key clinical point: routine thyroid testing before every glucose tolerance test is not necessary, but unexplained weight loss, tremor, heat intolerance, palpitations or goitre should prompt doctors to think about thyrotoxicosis before giving a carbohydrate load.

The report also adds to earlier case descriptions in the medical literature showing that thyrotoxic periodic paralysis is seen disproportionately in young men and may be more common in Asian populations. Specialist references note that attacks can follow high-carbohydrate meals, while other case reports describe similar episodes of sudden weakness and severe hypokalaemia linked to Graves’ disease. In this patient, careful treatment with potassium, magnesium and propranolol restored strength within 12 hours, and antithyroid treatment prevented further attacks over the following 24 weeks.