Introduction: Cranial nerve palsies have been reported in patients with uncontrolled hypothyroidism. We describe a case of overt hypothyroidism due to treatment disruption following radioiodine therapy, presented with a unilateral lower motor neuron seventh cranial nerve palsy. Case: A 32-year-old female presented with hypertension, dyslipidemia, class III obesity, and Graves’ disease post radioiodine therapy. She had stable thyroid function test with levothyroxine replacement post radioiodine. She presented with a 3-day history of right-sided facial droop associated with lethargy, weight gain, and constipation. She reported inadequate levothyroxine supply due to 2-month lapses in follow-up. On examination, there was a right-sided lower motor neuron 7th cranial nerve palsy with delayed ankle reflexes. No additional neurological deficits, goiter, cutaneous rashes, or vesicular lesions were noted. There was no preceding viral illness or otologic symptoms. Thyroid function tests showed overt hypothyroidism with thyroid-stimulating hormone 38 mIU/L, free thyroxine <5.4 pmol/L with a deranged lipid profile (total cholesterol: 8.8 mmol/L, low-density lipoprotein: 5.72 mmol/L, triglyceride: 1.77 mmol/L). Renal and liver function tests were within normal limits, with no leukocytosis. Neuroimaging of the brain was unremarkable. She was commenced on a short course of high-dose prednisolone, with no improvement in symptoms. Levothyroxine replacement therapy initiated led to progressive restoration of thyroid function, accompanied by symptom recovery. Conclusion Isolated lower motor 7th nerve palsy has been reported as a manifestation of hypothyroidism. This case underscores the importance of early recognition to enable timely and appropriate management, as patients with hypothyroidisminduced isolated seventh nerve palsy demonstrate marked recovery with adequate levothyroxine replacement.
Facial Nerve ; Hypothyroidism ; Motor Neurons ; Paralysis