Polyneuritis cranialis with generalized hyperreflexia as a presenting manifestation of thyrotoxicosis

A 22-year-old male student with no past medical illness, presented with acute onset dysarthria, binocular diplopia, and dysphagia over 10 hours. On examination, he had tachycardia, hypertension, generalized hyper-reflexia, and bilateral pupil sparing oculomotor, troclear, abducens, trigeminal, facial, glossopharyngeal, and vagus nerve palsy. Rest examination was unremarkable. Facial nerve conduction study (NCS) showed decreased amplitude bilaterally and neurogenic pattern on electromyography. Limb NCS, repetitive nerve stimulation, neostigmine test, brain magnetic resonance imaging, cerebrospinal fluid, and biochemical tests were normal. Only positive tests were low thyroid-stimulating hormone (TSH) (<0.01), high free T3 (19.2 pmol/L), and high free T4 (39.2 pmol/L). Thyroid ultrasonography, anti-thyroid peroxidase, and anti-thyroglobulin antibody were normal. Patient was treated with anti-thyroid drugs, with which he completely recovered in 2 months. Though many cases with thyrotoxic myopathy have been reported, only few mention neuropathic cause of dysphagia or polyneuritis cranialis. Getting done thyroid function tests may be helpful in patients with polyneuritis cranialis of uncertain etiology.