To describe an atypical manifestation of a patient with idiopathic intracranial hypertension.

Idiopathic intracranial hypertension (IIH) presents commonly with headache, visual disturbances, papilledema, visual field loss, and cranial nerve palsies, particularly of cranial nerve six. Here we describe a case with polyradiculopathy and areflexia caused by IIH to highlight an uncommon manifestation of this disease.

A 21-year-old obese female presented with headache and blurry vision of one week duration. She was diagnosed with IIH based on symptoms, papilledema on exam, and an opening pressure of >55 cm H20 on lumbar puncture. She was started on acetazolamide and three days later developed neck pain and left arm weakness. Examination demonstrated bilateral cranial nerve six palsies and proximal>distal left upper extremity weakness. Deep tendon reflexes (DTR) were absent throughout except for 2+ ankle jerks bilaterally. Repeat lumbar puncture showed CSF opening pressure of >55 cm H2O with normal basic studies. CT venogram did not show venous sinus thrombosis and MRI of cervical spine was normal. Due to persistent symptoms despite increasing her acetazolamide, an external ventricular drain (EVD) was placed. One day later, her left cranial nerve six palsy and her left arm weakness improved some. Her DTRs improved to 1+ throughout. Given the patient’s clinical improvement, a ventriculoperitoneal shunt (VPS) was placed and she had resolution of the weakness and hyporeflexia two days later.

This case adds to the literature of case reports showing polyradiculopathy and areflexia in the setting of fulminant raised intracranial pressure, necessitating emergent VPS. It is important to rule out other causes of raised intracranial pressure and extremity weakness. However, given the appropriate clinical context this should be on the differential. Although rare, recognition of this manifestation of IIH is necessary to institute appropriate treatment with a VPS to prevent long-lasting deficits.