CASE
A 77-year-old otherwise healthy male was brought to the emergency department complaining of a worsening headache and decreased vision for the past week. He had presented to urgent care 2 weeks earlier with a headache and earache. During that visit, an ears, nose, and throat surgeon confirmed a diagnosis of otitis media. The patient was treated with cephalexin for 5 days, and his symptoms had completely resolved.
When he subsequently developed a headache and diminished vision, the patient was seen by an ophthalmologist, who discovered papilledema with associated lateral rectus palsy likely caused by increased intracranial pressure. During an examination by the neurology department, the patient was alert and oriented and was found to have severe deafness, bilateral papilledema, and right sixth cranial nerve palsy. No facial asymmetry, pronator drift, gross motor weakness in the extremities, or incoordination was present. He was able to stand from a sitting position using support from a walker.
The patient's symptoms resembled right temporal lobe abscess secondary to mastoiditis. CT of the head was negative for abscess or mass effect (Figure 1),
suggesting meningeal malignancy or idiopathic intracranial hypertension (IIH). Lumbar puncture revealed clear CSF with raised pressure; WBC count of 11 with predominant lymphocytes; minimally raised protein level; normal glucose level; and no organisms. India ink and Gram stain test results were negative. Findings from a cytologic evaluation and workup for chronic meningitis were unremarkable. Based on his CSF results and the lack of a definite etiology, the patient was presumed to have IIH. The infection had likely spread to the venous sinuses, and venous thrombosis was suspected given his otitis media and mastoiditis, which rarely causes IIH. The patient was started on mannitol, IV ceftriaxone, and acetazolamide. MRI (Figure 2) and magnetic resonance venography (MRV) (Figure 3) of the brain were ordered. What do the images reveal?