Abstract
Introduction Well known neurological associations with thyrotoxicosis include myopathy, periodic paralysis and ophthalmoplegia. Thyrotoxic neuropathy aka ‘Basedow’s Paraplegia’ was described by Charcot in 1889 but remains rarely reported. We describe a case of subacute ophthalmoplegia, proximal and distal areflexic weakness in the setting of newly diagnosed thyrotoxicosis.
Case A 54-year-old previously well Chinese female presented with a 3-month history of progressive vertical diplopia, 20 kg of weight loss and symmetrical proximal limb weakness. Initial examination revealed a complex external ophthalmoplegia associated with peri-orbital swelling and lid retraction. Right eye elevation was impaired, and both vertical and horizontal movements were limited in the left eye. Symmetrical distal greater than proximal limb weakness including 3/5 ankle movements were recorded. Temperature and pain sensation was absent in a stocking distribution to the upper tibia associated with absent lower limb reflexes. Asymmetrical lower limb pitting oedema was also present. The gait demonstrated a waddling and high stepping quality. Investigations revealed a thyroid panel consistent with profound primary hyperthyroidism. Magnetic resonance imaging of the brain and orbits excluded cerebral lesions, cavernous sinus, or cranial nerve pathology. Interestingly, extra-ocular muscle enlargement was not present radiologically.
Conclusions This case represents a rare but described example of thyrotoxic neuropathy, which is likely an under recognised condition.
