Hypothyroidism can present with signs of cerebellar dysfunction1. Untreated hypothyroidism can progress to myxoedema coma, a rare condition with high mortality2. Sepsis is a common precipitant for myxoedema coma in untreated hypothyroidism.
A 59 year old woman presented with a 12 month history of cognitive decline, dysarthria and bilateral limb ataxia. She had dysdiadochokinesis, intention tremor and past pointing. Cranial nerves, power, tone and reflexes were normal. A provisional diagnosis of stroke was made and she was admitted under neurology. Non contrast CT brain was normal. On day three of admission the patient developed hypothermia (T 33.2°C), hypoglycaemia (glucose 3.5mmol/L), hyponatraemia (Na 124 mmol/L [135-145]), type 2 respiratory failure and tonic-clonic seizures. ECG showed sinus rhythm with QT prolongation. Thyrotropin (TSH) was 98 mIU/L [0.2-3.5] with undetectable free thyroxine (fT4), thyroid peroxidase antibody 880 IU/mL [0-35] but negative thyroglobulin antibody. Septic screen revealed Staphylococcus saprophyticus urinary tract infection.
The patient required intubation and ventilation for 2 days, and inotropic support for hypotension. She was passively rewarmed and treated with cefazolin and sodium valproate. 150mcg T4 was given followed by intravenous liothyronine (T3) 20mcg bd. Nasogastric T4 125mcg daily was poorly absorbed, so NG T4 and IV T3 were co-administered for 5 days. Glucocorticoid stress doses were given until exclusion of adrenal insufficiency was excluded on short synacthen test (Time 0: 242 nmol/L, Time 30: 578nmol/L, Time 60: 638 nmol/L [N > 550]). A cerebral MRI showed chronic microvascular disease. Lumbar puncture excluded infection, but demonstrated elevated protein (1.14 g/L [0.25-0.55]). Serum sodium normalised by day 7. Cerebellar signs and confusion had completely resolved by day 29. TSH was 6.53 mIU/L by discharge on day 34.
Patients presenting with neurological signs require exclusion of hypothyroidism. Neurological signs may resolve with treatment of hypothyroidism3. Myxoedema coma remains challenging to manage.