A low pressure headache, medically known as Intracranial Hypotension (IH), is caused by abnormally low pressure or volume of cerebrospinal fluid (CSF) surrounding the brain and spinal cord. CSF cushions the brain, but when its volume is reduced, the brain is no longer buoyant and sags slightly when the person is upright. While often treatable, this condition can occasionally signal a serious medical problem that requires immediate attention.
Understanding Low Cerebrospinal Fluid Pressure
The brain and spinal cord are enveloped by CSF, which acts as a shock absorber and provides nutritional support. This fluid is contained within membranes called meninges, which include the tough outer layer known as the dura mater. A low pressure headache occurs when CSF volume is reduced, most commonly due to a leak in the dura mater. This decrease causes the brain to descend slightly, stretching pain-sensitive structures like the meninges and blood vessels at the base of the skull.
The defining feature of this condition is its positional nature, often referred to as an orthostatic headache. The pain typically worsens significantly within minutes of standing or sitting upright and improves rapidly when the person lies down flat. The headache pain itself can vary in location but is frequently felt in the back of the head, sometimes accompanied by neck pain or stiffness.
Warning Signs Requiring Immediate Medical Attention
Although the positional headache is the most common symptom, the brain’s displacement can sometimes lead to dangerous complications that constitute a medical emergency. One concerning possibility is the development of a subdural hematoma, a collection of blood on the surface of the brain. This occurs when small blood vessels stretch and tear as the brain sags, and this complication can be life-threatening, requiring urgent intervention.
Any sudden change in mental status, such as confusion, severe drowsiness, or loss of consciousness, should be treated as an immediate emergency. Other neurological “red flags” indicate pressure on sensitive cranial nerves and require immediate medical evaluation. These symptoms include:
- Sudden confusion, severe drowsiness, or loss of consciousness
- New weakness or numbness on one side of the body
- Difficulty with balance or slurred speech
- Severe, persistent nausea and vomiting not relieved by lying down
- The onset of double vision (diplopia)
If any of these severe symptoms occur alongside a low pressure headache, seek emergency medical services immediately.
Typical Triggers of Low Pressure Headaches
The pressure drop is typically due to a leak in the dura mater, and the causes fall into two main categories. The most common identifiable cause is an iatrogenic leak, meaning it is related to a medical procedure. This includes a Post-Dural Puncture Headache (PDPH) following a spinal tap (lumbar puncture) or an epidural injection. In these cases, the needle creates a small hole in the dura mater that fails to seal completely, allowing CSF to leak out.
Another significant category is Spontaneous Intracranial Hypotension (SIH), where the leak occurs without an obvious preceding medical procedure or major trauma. The leak may result from minor events like a violent cough or sneeze, or it can be due to an underlying weakness in the spinal dura, sometimes associated with connective tissue disorders like Ehlers-Danlos syndrome. The location of the spontaneous leak can be challenging to find, sometimes requiring advanced imaging techniques like MRI or CT myelography.
Home Care and When to Consult a Specialist
When a low pressure headache is confirmed and no red flag symptoms are present, initial management focuses on conservative measures to help the leak seal and alleviate symptoms. Strict bed rest is often the most effective immediate measure, as lying flat minimizes the brain’s sagging and provides rapid symptom relief. Increasing fluid intake and consuming caffeine—either through beverages or pills—are also commonly recommended, as caffeine can cause cerebral vasoconstriction and help reduce headache severity.
Over-the-counter pain relievers like acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) may help manage discomfort, though they are often less effective than positional changes. If the headache persists beyond 48 hours despite consistent bed rest and home care, or if symptoms are severely debilitating, consult a neurologist or headache specialist. These specialists may recommend non-surgical treatments, such as an epidural blood patch, which involves injecting a patient’s own blood into the spinal space to effectively seal the CSF leak.