Makindo Medical Notes

🧠 Low CSF Pressure Headache (also called CSF leak headache or intracranial hypotension) occurs when cerebrospinal fluid (CSF) pressure falls below normal. This usually results from a spinal CSF leak, either spontaneous or iatrogenic. The hallmark is a postural headache—worse upright, relieved by lying flat.

📌 About

• Results from a reduction in CSF volume/pressure due to leakage.
• Leads to brain sagging within the skull, causing pain, cranial nerve stretch, and venous engorgement.
• Most often linked to lumbar puncture or spontaneous dural tear, but also seen after trauma or surgery.

🧬 Aetiology

• Spontaneous CSF Leak: Small dural tear, often thoracic or cervical spine. Associated with connective tissue disorders (e.g., Marfan, Ehlers–Danlos).
• Post-Lumbar Puncture: Commonest iatrogenic cause; dural puncture may not fully seal.
• Trauma: Spinal or head trauma tearing the dura.
• Post-Surgical: Especially after spinal/neurosurgical procedures.
• Connective Tissue Disorders: Weakened dura predisposes to leaks.

💡 CSF circulation: Produced by the choroid plexus in ventricles → flows via aqueducts & foramina → circulates in subarachnoid space → absorbed by arachnoid granulations → venous system. A leak disrupts this balance → ↓ intracranial pressure.

🩺 Clinical Features

• Headache: Diffuse, throbbing, often occipital. Worsens upright, relieved supine (orthostatic headache).
• May be worse in the morning and improve with rest.
• Associated symptoms: nausea, vomiting, neck stiffness, tinnitus, hearing changes.
• Cranial nerve palsies (esp. CN VI → diplopia) due to traction.
• Rare: cognitive slowing, encephalopathy, or coma in severe untreated cases ⚠️.

🔍 Investigations

• MRI brain with gadolinium: Shows diffuse meningeal enhancement, “brain sagging,” or subdural hygromas.
• Spinal MRI or CT myelography: To locate the leak (contrast extravasation).
• Intrathecal contrast MRI: High sensitivity for pinpointing leaks.
• Radioisotope cisternography: Rarely used now.

💊 Management

• Conservative: Bed rest, oral/IV fluids, caffeine (vasoconstrictor, ↑CSF production).
• Epidural Blood Patch: Standard treatment for post–lumbar puncture headache. Injected autologous blood seals leak; success rates >90%.
• Surgical Repair: Required for persistent or recurrent leaks (direct dural closure or fibrin glue).
• Symptomatic: Analgesics, antiemetics, avoidance of straining.
• Monitoring: Recurrence possible, esp. in connective tissue disorders.

📈 Prognosis

• Most post-LP leaks resolve with an epidural blood patch.
• Spontaneous leaks may require repeat interventions but often respond to targeted patches or repair.
• Untreated, chronic CSF hypotension can lead to subdural haematomas or permanent neurological deficits.