Intracranial hypertension is a serious medical condition that needs careful tests to confirm it, find any causes, and start the right treatment. Doctors use a mix of medical history, physical exams, eye checks, brain scans, and spinal fluid tests to diagnose it. Quick and accurate diagnosis helps prevent complications, especially permanent vision loss and brain damage.
Medical History and Symptoms
The first step is to take a detailed medical history. The doctor asks about symptoms like ongoing headaches, vision problems, nausea, ringing in the ears, or changes in thinking. They want to know if symptoms started suddenly or slowly, how long they last, and if they get worse at certain times or positions. The doctor also asks about risk factors such as obesity, recent weight gain, pregnancy, or use of medicines that can raise pressure, like tetracyclines, retinoids, or hormone treatments.
Physical and Neurological Exam
Next, the doctor performs a thorough physical and neurological exam. They look for signs of high pressure, especially swelling of the optic disc called papilloedema. This is the most reliable sign of raised intracranial pressure. Doctors use an ophthalmoscope to check for it. If papilloedema is found, it strongly suggests intracranial hypertension. They also check for nerve problems such as sixth cranial nerve palsy, which causes double vision, abnormal eye movements, or lowered consciousness. These signs may show the condition is severe or worsening fast.
Brain Imaging Tests
Many symptoms of intracranial hypertension can be caused by other problems like brain tumors, migraines, infections, or blood vessel issues. Therefore, brain imaging is very important. MRI scans are usually the first test. MRI can rule out tumors, hydrocephalus, blood clots, or birth defects. It may also show subtle signs of idiopathic intracranial hypertension, such as flattening of the back of the eye, swelling of optic nerve sheaths, empty sella, or narrowing of venous sinuses.
If blood clots in brain veins are suspected, doctors use MR venogram (MRV) or CT venogram (CTV). These scans check the veins that drain blood from the brain. Blocked veins can raise pressure and must be found and treated. Venograms provide detailed views that standard MRI or CT might miss.
Lumbar Puncture (Spinal Tap)
A key test for diagnosis is the lumbar puncture. This involves inserting a needle into the lower spine to collect cerebrospinal fluid (CSF). Doctors measure the opening pressure of CSF. In adults, pressure above 20 cm H₂O (or 25 cm H₂O in obese people) is high. The fluid is also checked for infection, bleeding, or inflammation. If the CSF is normal but pressure is high, and scans show no other cause, doctors may diagnose idiopathic intracranial hypertension (IIH).
For children, the normal pressure ranges differ, and doctors consider age, weight, and other health issues when interpreting results. Children may need sedation for scans and lumbar puncture. Infants with a bulging soft spot on the head or unusually large head size might be suspected of raised pressure before testing.
Eye Exams
Patients with vision problems need thorough eye exams. Eye specialists may perform:
- Visual field tests to check peripheral vision loss
- Fundoscopy to see optic nerve swelling
- Optical coherence tomography (OCT) to measure the thickness of retinal nerve fibers
- Visual acuity tests to check sharpness of vision
These tests show how much the optic nerve is affected and help track changes over time. OCT is a non-invasive scan that can detect early swelling before symptoms appear.
Lumbar Drain Trial
Sometimes, doctors do a lumbar drain trial, where they remove some spinal fluid temporarily to see if symptoms improve. Improvement in headaches or vision after fluid removal supports the diagnosis of intracranial hypertension and helps guide treatment decisions, like shunt surgery.
Diagnostic Criteria and Differential Diagnosis
After tests, doctors classify the condition as idiopathic or secondary intracranial hypertension based on cause. Diagnosing IIH requires meeting criteria known as the modified Dandy criteria:
- Symptoms and signs of high pressure (headache, papilloedema, pulsatile tinnitus)
- No other neurological problems except possible sixth nerve palsy
- High CSF pressure with normal fluid composition
- Normal brain scans without other causes
Doctors must also rule out other conditions that look similar, such as:
- Brain tumors
- Chiari malformations
- Meningitis or encephalitis
- Chronic daily headaches or medication-overuse headaches
- Inflammation of brain blood vessels (vasculitis)
Careful evaluation ensures the right diagnosis, especially in tricky cases.
Summary
Diagnosing intracranial hypertension requires teamwork and many tests: medical history, physical exam, brain scans, lumbar puncture, and eye checks. Quick and correct diagnosis is key to guiding treatment, watching for changes, and preventing serious problems like vision loss or brain herniation. Awareness of this condition, especially in young women with idiopathic cases, leads to earlier care and better results.
