A 22-year-old woman presents to her physician’s office complaining of a persistent headache and blurry vision for approximately 3 months. The patient states that the headache is retro-orbital and bilateral. The patient has been seen before with a history of severe acne refractory to benzoyl peroxide and minocycline, successfully treated 4 months ago with oral isotretinoin. She has no other medical history or allergies. Her last menstrual period was 3 weeks ago, lasting 3 days with no abnormal bleeding. The patient is in a monogamous relationship with her husband, and they use barrier contraception. She does not smoke cigarettes or drink alcohol but occasionally uses marijuana, although she has not used any for the last three months due to her symptoms. Temperature is 99.0°F (37.2°C), blood pressure 126/82 mmHg, pulse 92/min, respirations 16 min, oxygen saturation 98% on room air, 5’10”, and weight 150 pounds. Physical examination shows bilateral papilledema on fundoscopy, with 20/20 vision in both eyes with corrective lenses. She has no rashes, and the examination is otherwise unremarkable. A CT of the brain without contrast is normal. Lumbar puncture shows an opening pressure of 32 cm H2O, and normal CSF with no RBCs or WBCs found.
C) Isotretinoin
The patient has Idiopathic Intracranial Hypertension (IIH), also known as pseudotumor cerebri. It is most likely due to isotretinoin, a vitamin A analog prescribed to the patient for control of her acne. IIH can be caused by several medications, including vitamin A and its analogues, tetracyclines (such as minocycline and doxycycline), recombinant growth hormone, and lithium. IIH is caused by an excess of CSF. Vitamin A is believed to cross the blood-brain barrier and increase CSF production through an effect on aquaporins in the cell membranes of the choroid plexus. Treatment of IIH is through acetazolamide, which reduces CSF levels.
Answer choice A: Corticosteroids, is incorrect. Corticosteroids are thought to decrease IIH, however, because of excess weight gain, which can cause IIH, corticosteroids are not used anymore because of weight gain.
Answer choice B: Herpes simplex virus encephalitis, is incorrect. Herpes simplex can cause encephalitis, with complaints similar to the patients’ complaints, and can even show normal results on CT scan and lumbar puncture, but generally only very early in the course of the disease. Encephalitis involving the herpes simplex virus is a medical emergency and would not be expected to last for 3 months.
Answer choice D: Obesity, is incorrect. Being overweight is a risk factor for IIH but is not identified as a direct cause. This patient is not obese.
Answer choice E: Rupture of the anterior communicating artery, is incorrect. A hemorrhagic stroke caused by a rupture of the anterior communicating artery would cause headaches and vision problems but likely would also cause many other signs and symptoms. This patient also has a normal CT scan, effectively ruling out an intracranial bleed.
Key Learning Point
Idiopathic Intracranial Hypertension (IIH) is defined by clinical criteria that include signs and symptoms specific to those produced by increased intracranial pressure (e.g., headache, vision loss), elevated intracranial pressure ICP with normal cerebrospinal fluid (CSF) composition, and no other cause of intracranial hypertension evident on neuroimaging or other evaluations. IIHcan be caused by various drugs, including vitamin A and its analogues, tetracyclines, recombinante growth hormone, and lithium.
