A 33-year-old woman comes to the office due to a 4-month history of worsening frontal headaches and neck pain. The headaches were infrequent in the beginning but over the past 4 weeks, they have become persistent. The patient has no fever. Symptoms are particularly bothersome because they interfere with sleep. Family history is significant for migraines. Temperature is 37 C (98.6 F), blood pressure is 128/74 mm Hg, pulse is 76/min, and respirations are 14/min. BMI is 40 kg/m2. On physical examination, pupils are equally round and reactive to light. Visual acuity is 20/20 in both eyes. Mild neck stiffness is present. Head imaging reveals no abnormalities. Laboratory results from cerebrospinal fluid are as follows:
| Opening pressure | 340 mm H2O |
| Glucose | 75 mg/dL |
| Protein | 20 mg/dL |
| Leukocytes | 1 cell/µL |
| Red blood cells | 0 cells/µL |
| Gram stain | negative |
Which of the following is the most likely cause of this patient's condition?
Idiopathic intracranial hypertension | |
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CSF = cerebrospinal fluid. | |
This patient with progressive headache, neck pain/stiffness, and obesity (ie, BMI ≥30 kg/m2) has elevated intracranial pressure (ICP) despite normal composition of the cerebrospinal fluid (CSF) and normal neuroimaging, consistent with idiopathic intracranial hypertension (IIH).
Headache is the most common presenting symptom in patients with increased ICP. Headaches associated with IIH classically worsen while the patient is in the recumbent position (during the night or on waking in the morning) or is straining (eg, during bowel movements or heavy lifting); however, many different headache patterns exist. Often, the headache of IIH may be similar to, or superimposed on, other primary headache disorders (eg, migraine, tension-type), as well as confounded by headaches associated with obstructive sleep apnea, which is common in obese patients.
Because headache is common and often nonspecific, the presence of other symptoms such as visual obscurations, pulsatile tinnitus, and neck pain and stiffness (possibly from increased pressure transmitted to cervical nerve sheaths) should raise suspicion for IIH, especially in obese women of childbearing age. Imaging shows normal brain parenchyma and lumbar puncture shows elevated opening pressure (eg, 250 mm H2O or higher) with normal CSF composition.
(Choice A) Aqueductal stenosis leading to hydrocephalus can present with signs and symptoms of increased ICP. However, CT scan would reveal enlargement of the lateral and third ventricles. Opening pressure may be normal because the obstruction occurs proximal to where the CSF flows into the spinal canal.
(Choice B) Fungal meningitis often presents subacutely with symptoms of headache and neck stiffness with elevated ICP on lumbar puncture. However, CSF analysis typically shows some combination of elevated protein concentration, low glucose concentration, and/or pleocytosis.
(Choice D) Although migraine headaches are often familial and symptoms may be indistinguishable from those of IIH, this patient's progressive course and associated neck pain warrant further evaluation. Lumbar puncture showing elevated opening pressure confirms IIH.
(Choice E) Temporal arteritis (TA) commonly presents with headache. Although neck pain may be present from commonly associated polymyalgia rheumatica, TA almost never occurs in patients age <50, constitutional symptoms (eg, fever, weight loss) are common, and increased ICP is not seen.
Educational objective:
Headaches due to idiopathic intracranial hypertension can be difficult to distinguish clinically; further evaluation is often required, especially in obese women of childbearing age with progressively worsening symptoms. Normal neuroimaging with an increased opening pressure and normal composition of the cerebrospinal fluid on lumbar puncture are diagnostic of idiopathic intracranial hypertension.