Severe hypertension and raised haematocrit: unusual presentation of Guillain-Barré syndrome.

A 36 year old man presented with headache, polyuria, thirst and weakness of the lower limbs. Hypertension and a high haematocrit were striking features on initial assessment. Subsequently the full picture of Guillain-Barré syndrome developed. Hormone measurement revealed marked sympathetic nervous system and renin-angiotensin system activation with a return to normal of both blood pressure and hormones with neurological recovery.