When a headache lessens or disappears entirely upon lying down, it is often referred to as an orthostatic or postural headache. This pattern of pain, worse when upright and relieved by a horizontal position, is a notable symptom that can indicate certain medical conditions. Recognizing this type of headache is an important step toward understanding its underlying cause.
Why Lying Down Provides Relief
The improvement of headache symptoms when lying down is closely related to the pressure of cerebrospinal fluid (CSF) surrounding the brain and spinal cord. CSF acts as a cushion, supporting and protecting these structures. When a person is upright, gravity exerts a downward pull on this fluid and the brain itself.
If there is a reduced volume or pressure of CSF, the brain can sag within the skull. This “brain sag” can lead to stretching on pain-sensitive structures like the meninges, the protective membranes encasing the brain and spinal cord, and blood vessels. This mechanical stress generates the headache pain experienced in an upright posture.
Lying flat helps to counteract this gravitational effect. When horizontal, CSF pressure becomes more even, reducing the downward pull on the brain. This allows the brain to regain its normal buoyancy and alleviates tension on the pain-sensitive structures, leading to a reduction of the headache.
Common Underlying Conditions
Headaches that improve when lying down are frequently associated with conditions that cause low cerebrospinal fluid pressure, medically known as intracranial hypotension. A prominent cause is Spontaneous Intracranial Hypotension (SIH), which results from a cerebrospinal fluid leak. This leak occurs when a tear in the dura mater, the outermost meningeal layer, allows CSF to escape from the spinal canal.
These leaks can happen spontaneously, sometimes due to minor trauma like a sneeze or cough, or in individuals with weaker connective tissues. SIH headaches are typically worse when upright and often relieved within 20-30 minutes of lying down. Another common cause is Post-Dural Puncture Headache (PDPH), which can occur after medical procedures such as a lumbar puncture (spinal tap) or epidural injections. These procedures can inadvertently create a small hole in the dura, leading to CSF leakage and subsequent low pressure.
PDPH symptoms are very similar to SIH, worsening when sitting or standing and improving when lying flat. Both SIH and PDPH stem from a loss of CSF volume, which disrupts the normal cushioning effect for the brain. Medical evaluation is required to identify the leak source and determine the appropriate course of action.
Seeking a Diagnosis
Proper diagnosis of a headache that improves when lying down typically begins with a thorough medical history and physical examination by a healthcare professional, often a neurologist. The pattern of the headache, including its positional nature and any accompanying symptoms like neck pain, nausea, or changes in hearing or vision, provides important clues.
Imaging studies are crucial for confirming a CSF leak and identifying its location. Magnetic Resonance Imaging (MRI) of the brain and spine is commonly performed, often with gadolinium contrast, to look for signs of low CSF pressure, such as brain sag or fluid collections around the spinal cord. If an MRI suggests a leak but doesn’t pinpoint the exact site, specialized imaging like Computed Tomography (CT) myelography or dynamic CT myelography may be used.
CT myelography involves injecting a contrast dye into the spinal fluid and then taking CT scans to visualize the flow of CSF and identify any leakage points. Dynamic CT myelography provides real-time imaging of CSF movement, which can be particularly helpful for detecting subtle or high-flow leaks. These tests aim to locate the dural tear or other abnormalities causing the CSF loss, guiding subsequent treatment decisions.
Management and Treatment
Initial approaches to managing headaches related to low CSF pressure often involve conservative measures. These include strict bed rest, encouraging the patient to lie flat for a period, and ensuring adequate hydration, sometimes with increased fluid intake. Caffeine, either orally or intravenously, may also be recommended as it can help constrict blood vessels and temporarily alleviate headache symptoms.
If conservative treatments do not provide sufficient relief, medical interventions are considered. A common procedure is an epidural blood patch, where a patient’s own blood is injected into the epidural space of the spine, near the suspected leak site. The injected blood forms a clot that can seal the dural tear, restoring CSF pressure and alleviating the headache.
For persistent leaks, especially those that do not respond to blood patches, other options include epidural fibrin glue patches or surgical repair. Fibrin glue, a biological adhesive, can be injected to seal the leak, offering an alternative when blood patches are not effective or contraindicated. In some cases, if the precise location of the leak is identified and other methods fail, surgical intervention may be necessary to directly repair the dural tear.