Pseudotumor Cerebri

Overview

Pseudotumor cerebri, literally meaning "false brain tumor," occurs when the pressure inside the skull (intracranial pressure) increases for no obvious reason. The symptoms mimic those of a brain tumor, but no tumor is present. The condition is now more commonly referred to as idiopathic intracranial hypertension (IIH) to better reflect its nature as a disorder of elevated intracranial pressure of unknown cause.

This condition primarily affects women of childbearing age, particularly those who are overweight. The annual incidence is approximately 1-2 per 100,000 in the general population, but rises to 15-20 per 100,000 in obese women aged 20-44 years. While the condition can occur in children and men, it is significantly less common in these populations.

The increased pressure can cause swelling of the optic nerve (papilledema) and lead to vision problems, which can become permanent if not treated promptly. Early diagnosis and treatment are crucial to prevent irreversible vision loss. With appropriate management, most patients can achieve good outcomes, though some may require long-term treatment to control symptoms and preserve vision.

Symptoms

The symptoms of pseudotumor cerebri result from increased intracranial pressure and its effects on surrounding structures, particularly the optic nerves. Symptoms can vary in severity and may develop gradually or appear suddenly.

Primary Symptoms

• Headache - Often severe, daily, and worsening with eye movements or straining
• Diminished vision - Including blurred vision, double vision, or brief episodes of blindness
• Pain in eye - Often accompanying eye movements
• Dizziness - May include vertigo or lightheadedness
• Pulsatile tinnitus - Whooshing sound in ears synchronized with heartbeat
• Neck and shoulder pain
• Nausea and vomiting

Vision-Related Symptoms

• Transient visual obscurations - Brief episodes of vision loss lasting seconds
• Peripheral vision loss - Progressive narrowing of visual field
• Diplopia (double vision) - Usually horizontal
• Photophobia - Light sensitivity
• Visual field defects - Blind spots or areas of reduced vision

Associated Symptoms

• Abnormal involuntary movements - Less common but may occur
• Cognitive difficulties - Problems with concentration or memory
• Depression or anxiety
• Fatigue
• Facial pain or numbness

The headaches associated with pseudotumor cerebri are typically described as pressure-like or throbbing, often worse in the morning or when lying down. They may be accompanied by pain behind the eyes and can be exacerbated by coughing, straining, or bending over. Visual symptoms are particularly concerning as they may indicate optic nerve damage that could become permanent without treatment.

Causes

The exact cause of pseudotumor cerebri remains unknown in most cases, hence the term "idiopathic." However, the condition is thought to result from problems with cerebrospinal fluid (CSF) dynamics, leading to increased intracranial pressure.

Proposed Mechanisms

• Increased CSF production: Overproduction by the choroid plexus
• Decreased CSF absorption: Impaired drainage through arachnoid granulations
• Venous outflow obstruction: Narrowing of venous sinuses
• Increased brain water content: Cerebral edema
• Hormonal influences: Effects on CSF dynamics

Secondary Causes

When an underlying cause is identified, the condition is termed secondary intracranial hypertension:

Medications

• Vitamin A derivatives (isotretinoin, tretinoin)
• Tetracycline antibiotics (doxycycline, minocycline)
• Growth hormone
• Corticosteroid withdrawal
• Lithium
• Oral contraceptives

Medical Conditions

• Sleep apnea
• Polycystic ovary syndrome
• Chronic kidney disease
• Cushing's syndrome
• Thyroid disorders
• Anemia

Venous Abnormalities

• Cerebral venous sinus thrombosis
• Venous sinus stenosis
• Jugular vein compression

Risk Factors

Several factors increase the risk of developing pseudotumor cerebri. Understanding these can help identify at-risk individuals and potentially prevent the condition.

Primary Risk Factors

• Obesity: BMI >30, especially recent weight gain
• Female gender: 4-20 times more common in women
• Childbearing age: Peak incidence in 20s and 30s
• Recent weight gain: Even 5-15% increase in body weight

Medical Risk Factors

• Polycystic ovary syndrome (PCOS)
• Sleep apnea
• Chronic kidney disease
• Endocrine disorders
• Iron deficiency anemia
• Systemic lupus erythematosus

Medication-Related Risk Factors

• Use of medications listed in causes section
• Recent initiation or discontinuation of certain drugs
• High-dose vitamin A supplements

Diagnosis

Diagnosing pseudotumor cerebri requires a systematic approach to confirm increased intracranial pressure while ruling out other causes. The modified Dandy criteria are commonly used for diagnosis.

Diagnostic Criteria

All of the following must be present:

• Signs and symptoms of increased intracranial pressure
• Elevated CSF opening pressure (>250 mm H2O in adults)
• Normal CSF composition
• Normal neuroimaging (except for signs of elevated pressure)
• No other cause of intracranial hypertension identified

Clinical Examination

• Ophthalmologic examination:
  • Fundoscopy to detect papilledema
  • Visual acuity testing
  • Visual field testing (perimetry)
  • Color vision assessment
  • Pupillary reflex testing
• Neurological examination: To rule out focal deficits
• Blood pressure and BMI measurement

Imaging Studies

• MRI brain with venography:
  • Rules out mass lesions
  • Evaluates for venous sinus thrombosis
  • May show signs of elevated pressure
• CT scan: If MRI unavailable
• Orbital ultrasound: Can detect optic nerve sheath distension

Lumbar Puncture

• Essential for diagnosis
• Performed after neuroimaging
• Measures opening pressure
• CSF analysis to rule out infection or inflammation
• May provide temporary symptom relief

Additional Testing

• Blood tests to identify secondary causes
• Sleep study if sleep apnea suspected
• Endocrine evaluation if indicated

Treatment Options

Treatment of pseudotumor cerebri aims to reduce intracranial pressure, relieve symptoms, and preserve vision. The approach depends on symptom severity and presence of vision loss.

Conservative Management

Weight Loss

• Primary treatment for overweight patients
• Even 5-10% weight reduction can improve symptoms
• Dietary counseling and exercise programs
• Bariatric surgery for severe obesity

Dietary Modifications

• Low-sodium diet (< 2g/day)
• Fluid restriction in some cases
• Avoiding caffeine withdrawal

Medical Treatment

First-Line Medications

• Acetazolamide:
  • Carbonic anhydrase inhibitor
  • Reduces CSF production
  • Starting dose: 500-1000mg/day
  • May increase up to 4g/day
• Topiramate:
  • Alternative to acetazolamide
  • Additional benefit of appetite suppression
  • 25-200mg/day

Second-Line Medications

• Furosemide
• Methazolamide
• Short-term corticosteroids for acute vision loss

Interventional Procedures

Serial Lumbar Punctures

• Temporary symptom relief
• Bridge to other treatments
• Not recommended as sole long-term therapy

Surgical Options

• Optic nerve sheath fenestration:
  • For progressive vision loss
  • Creates window in optic nerve sheath
  • Protects optic nerve from pressure
• CSF shunting:
  • Ventriculoperitoneal or lumboperitoneal shunt
  • For medically refractory cases
  • Requires long-term monitoring
• Venous sinus stenting:
  • For documented venous stenosis
  • Emerging treatment option

Monitoring and Follow-up

• Regular ophthalmologic examinations
• Serial visual field testing
• Weight monitoring
• Medication side effect assessment
• Long-term surveillance for recurrence

Prevention

While not all cases of pseudotumor cerebri can be prevented, certain measures may reduce risk or prevent recurrence.

Weight Management

• Maintain healthy BMI (<25)
• Avoid rapid weight gain
• Regular physical activity
• Balanced, nutritious diet

Medication Awareness

• Review medications with healthcare providers
• Avoid known triggering medications when possible
• Monitor for symptoms when starting new medications
• Report visual changes promptly

Health Monitoring

• Regular eye examinations
• Management of associated conditions
• Treatment of sleep apnea if present
• Control of hormonal disorders

When to See a Doctor

Early medical evaluation is crucial for preserving vision and preventing complications. Certain symptoms require immediate attention.

Seek Emergency Care For:

• Sudden, severe vision loss
• Complete loss of vision in one or both eyes
• Severe headache with confusion
• High fever with headache
• Seizures
• Loss of consciousness

Schedule Urgent Appointment For:

• Progressive vision changes
• Persistent, worsening headaches
• Double vision
• Pulsatile tinnitus
• Brief episodes of vision loss
• Eye pain with movement

Related Conditions