A spinal headache, formally known as a post-dural puncture headache, is severe head pain occurring after medical procedures involving the spine. It arises from an unintended leak of cerebrospinal fluid (CSF), the clear fluid that surrounds and cushions the brain and spinal cord. Procedures like a lumbar puncture (spinal tap) or the placement of an epidural can lead to this complication. The resulting reduction in fluid volume decreases the pressure around the brain, causing the characteristic pattern of discomfort.
The Defining Feature: Positional Pain
The defining characteristic of a spinal headache is its positional nature. When a person is upright, either sitting or standing, the pain intensifies rapidly, often reaching a debilitating level within minutes. This intensification is caused by the downward pull on the brain, which strains pain-sensitive structures when the cushioning CSF volume is low.
The contrast in pain level with a change in posture is immediate and profound. Lying down flat, especially in a supine position, typically provides swift and significant relief, often causing the pain to disappear entirely. This rapid shift from excruciating pain to near-total comfort upon reclining is the defining diagnostic sign.
Location and Quality of the Discomfort
The physical sensation of a spinal headache is frequently described as a deep, heavy, or throbbing pain. The intensity can range from bothersome to overwhelmingly severe. The pain is often felt bilaterally, meaning on both sides of the head, and may be concentrated in the back, or occipital region.
The discomfort may also be localized to the forehead, or frontal area, and sometimes affects the entire head. In many cases, the ache begins at the base of the skull and radiates downward to involve the neck and shoulders. The quality of the pain is described as pressure-like, reflecting the change in intracranial pressure.
Accompanying Symptoms That May Occur
Beyond the head pain, a spinal headache is often accompanied by several other neurological symptoms. Neck stiffness or pain is common, as the drop in CSF volume can cause traction on supporting structures. Many individuals experience gastrointestinal upset, manifesting as nausea and sometimes vomiting. Sensory disturbances are also frequently reported, including:
- Photophobia (heightened sensitivity to light)
- Phonophobia (intolerance to loud sounds)
- Changes in hearing, such as muffled sounds or tinnitus (ringing sensation)
- Blurred or double vision, and general dizziness
How and When the Headache Typically Starts
The underlying mechanism for a spinal headache is intracranial hypotension, or abnormally low pressure inside the skull. This is caused by the continuous leakage of cerebrospinal fluid after the dura mater (the tough outer membrane surrounding the spinal cord) is punctured. This loss of fluid volume decreases the buoyant support for the brain, causing it to shift slightly downward.
The onset of the headache is usually delayed, not occurring immediately after the procedure. In most instances, the severe pain begins between 24 and 48 hours following the lumbar puncture or epidural. While onset can sometimes be quicker (within a few hours) or significantly delayed (up to five to seven days), the typical timeline helps confirm the diagnosis.