Case Study of the Week: Pseudotumor Cerebri

Don't you hate those diagnoses you cannot make with a simple physical exam or routine lab work, the diagnoses that are potentially serious but often disguise themselves as more benign conditions?  Pseudotumor cerebri is one of these tricky medical conditions- often initially misdiagnosed as a migraine headache but essential to treat properly.  To learn more about this interesting condition and hone our diagnostic skills, I have chosen pseudotumor cerebri for this week's case study.

Pseudotumor cerebri, also know as idiopathic intracranial hypertension, is a disorder involving increased intracranial pressure and is most common in obese women of childbearing age.  The specific cause of this condition is unknown.  Some medications such as Vitamin A supplements, tetracycline antibiotics and steroids have been associated with development of pseudotumor cerebri.  Weight gain is also suspected to play a role.  Multiple theories attempt to explain the mechanism of pseudotumor cerebri including increased production of cerebrospinal fluid (CSF) and increased blood flow to the brain. 

Case Presentation

A 35 year old woman presents to your clinic complaining of a headache for the past five days.  She describes the headache as a throbbing, and a constant pressure.  The headache is worse upon waking in the morning.  She describes feeling dizzy and nauseous which is accompanied by blurred vision.  She states that her vision intermittently 'blacks out' for a few seconds.  She also hears a whooshing sound in her right ear and has some pain in her eyes.  The patient is hypertensive with a blood pressure of 152/94.  All other vital signs are normal.  The woman has a history of obesity and hypertension. 

On exam you note the patient appears to be in a moderate amount of pain as a result of her headache.  Neurologically, the patient's cranial nerves appear intact and cerebellar exam is normal.  The patient is alert and oriented.  On ocular exam you note papilledema (optic disc swelling) bilaterally.  Visual acuity is normal.  Based on this patients eye exam and symptoms, you suspect pseudotumor cerebri as a potential cause of this patient's headache and plan to order further testing to confirm your suspicions. 

Management and Outcome

MRI of the brain is the test of choice to confirm diagnosis of pseudotumor cerebri and rule out other causes of headache.  CT can also be used although MRI is recommended as it is more effective in ruling out a mass, brain lesion or sinus thrombosis.  Subtle MRI changes such as decreased ventricle size can indicate pseudotumor cerebri however CT and MRI do not conclusively diagnose this condition.  Once a mass or lesion is ruled out with MRI, lumbar puncture should be preformed.  Opening pressure on lumbar puncture is often elevated in pseudotumor cerebri.  Symptoms may improve or be relieved with lumbar puncture as CSF is removed.  CSF analysis should be performed to rule out other causes of headache and will be normal in patients with pseudotumor.  

Pseudotumor cerebri must be closely managed by a neurologist.  Conservative treatment of pseudotumor cerebri involves weight loss.  A reduction of weight by just 5 to 10% is associated with a reduction in intracranial pressure and resolution of papilledema.   Vision loss is the most significant complication of pseudotumor cerebri therefore the goal of treatment is preserving visual function.  Optic nerve function must be continually assessed to rule out worsening of the condition.  In patients without visual loss, a carbonic anhydrase inhibitor such as Diamox is given to lower intracranial pressure.  If vision loss occurs, emergent surgery to relieve pressure on the optic nerve must be done to prevent deterioration of vision.  In severe cases, a shunt can be placed in the brain to drain CSF relieving intracranial pressure. 

Discussion

As nurse practitioners it is imperative that we recognize the signs and symptoms of pseudotumor cerebri to prevent permanent vision loss in our patients suffering from this condition.  It is important to involve a physician in suspected cases of pseudotumore cerebri as lumbar puncture is necessary.  Educate yourself about papilledema and practice your eye exam skills so you will be able to recognize this sign of idiopathic intracranial hypertension allowing your patients to receive prompt treatment. 

Have you ever diagnosed a case of pseudotumor cerebri?  

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Cynthia Brito