CSF leak
A leak of cerebrospinal fluid lowers the pressure cushioning the brain, producing a headache that is much worse upright and eases on lying flat. Treatable, but often mistaken for migraine for years.
~5 per 100,000 each year · likely underdiagnosed · peaks between the 30s and 50s
What a CSF leak is
Cerebrospinal fluid (CSF) surrounds the brain and spinal cord and keeps the brain buoyant. When it leaks, usually from a tear in the membrane around the spinal cord, the pressure falls and the brain loses some of its cushioning. The hallmark is an orthostatic headache: one that comes on or worsens within minutes of being upright and settles after lying down.
Leaks can follow a lumbar puncture, spinal injury or surgery, but many are spontaneous, sometimes linked to connective-tissue conditions. The spontaneous form is properly called spontaneous intracranial hypotension.
Why it is so often missed
Early on, the upright-worse pattern is striking, but over time it can blur and start to resemble chronic migraine, which is why people are frequently treated for the wrong condition for years. The positional history is the clue worth holding onto.
- Headache worse upright, better lying flat, often within 15 to 30 minutes
- Neck pain or stiffness, sometimes with nausea
- Muffled hearing, tinnitus or a sense of pressure in the ears
- Symptoms that tend to worsen as the day goes on
How it is treated
Many leaks settle with rest, fluids and time. When they do not, an epidural blood patch, where a small amount of the person's own blood is used to seal the leak, is often effective. Imaging can help locate a stubborn leak before more targeted treatment.
From your story to a working plan
- 01The intake screens specifically for the upright-worse, lying-better pattern that points away from migraine
- 02Your assessment flags red flags and the need for prompt imaging or specialist referral where appropriate
- 03You receive a plain-language summary; your clinician receives a structured SOAP note where licensed
- 04Education explains what an epidural blood patch involves and the questions worth asking
