A high pressure headache results from elevated Intracranial Pressure (ICP), the pressure inside the skull and around the brain. This condition, known as Intracranial Hypertension (IH), is typically caused by an excessive buildup of cerebrospinal fluid (CSF) or structural issues within the cranial cavity. Since elevated ICP can affect the optic nerve and potentially cause permanent vision loss, timely medical evaluation is extremely important.
Recognizing the Symptoms
The pain associated with high ICP is often persistent, throbbing, or generalized, differing from common migraines or tension headaches. The headache may be particularly severe upon waking in the morning. A unique feature is that the pain frequently worsens with activities that momentarily increase pressure, such as coughing, straining, or bending over. The intensity often increases when lying down and improves when standing upright.
The elevated pressure on the brain and optic nerve causes several distinguishing neurological and visual symptoms. A common complaint is pulsatile tinnitus, a rhythmic whooshing sound heard in the ears that synchronizes with the heartbeat. Visual disturbances can include temporary vision loss, often described as a graying or blackout of sight, or double vision (diplopia). The pressure on the optic nerve causes physical swelling visible during an eye exam, known as papilledema, which signals a serious risk for permanent vision loss.
Causes of Elevated Intracranial Pressure
The underlying reasons for elevated ICP fall into two main categories: cases where a specific cause can be identified, and those where the cause remains unknown. The most common form of the unknown category is Idiopathic Intracranial Hypertension (IIH). IIH occurs most frequently in women of childbearing age who are also overweight, and it is thought to involve issues with CSF absorption or the flow of blood out of the brain’s venous sinuses.
Conditions where a specific cause can be found are referred to as secondary Intracranial Hypertension. These causes often involve a disruption to the balance of CSF production, circulation, and absorption. For example, a blockage in the large veins that drain blood from the brain, known as venous sinus thrombosis, can cause blood to back up and increase pressure. Certain medications, including tetracyclines, high-dose Vitamin A derivatives, or the starting or stopping of steroids, have also been linked to elevating ICP. Structural issues like tumors, masses, or hydrocephalus also directly contribute to increased pressure.
Diagnosis and Confirmation
Confirming a high pressure headache requires a systematic approach to first rule out structural causes and then directly measure the fluid pressure. Initial steps involve neurological and ophthalmological examinations, where doctors specifically look for papilledema, the swelling of the optic disc, which is present in most cases of IIH. Imaging tests, such as MRI or CT scans, are performed primarily to ensure that the increased pressure is not due to a brain tumor, bleeding, or other space-occupying lesion.
Once structural causes have been eliminated, the definitive diagnostic procedure is a Lumbar Puncture (LP), commonly known as a spinal tap. During this procedure, a specialized needle is inserted into the lower back to access the cerebrospinal fluid. The pressure of the CSF is measured using a manometer before any fluid is removed, providing an opening pressure reading. For adults, a reading of 25 cm of water or higher confirms the diagnosis of intracranial hypertension, provided the CSF composition is otherwise normal.
Treatment Options
The management of a high pressure headache is focused on two main goals: lowering the elevated intracranial pressure to preserve vision and alleviating the persistent headache symptoms. Initial medical management involves pharmacological agents, primarily diuretic medications known as carbonic anhydrase inhibitors. These drugs, such as acetazolamide, work by decreasing the rate at which cerebrospinal fluid is produced within the brain, thereby reducing the overall pressure inside the skull.
For patients diagnosed with IIH, lifestyle modifications are an important component of long-term treatment. Weight loss is considered the only disease-modifying therapy for this patient group, as even a modest reduction in total body weight (5% to 10%) has been shown to reduce ICP and improve symptoms. Some medications, like topiramate, may be used as a secondary option, as they offer the dual benefit of reducing CSF production while also promoting weight loss.
If medical treatments and lifestyle changes fail to control the pressure or if vision loss becomes an immediate threat, surgical interventions may be necessary. One common surgical option is the placement of a shunt, such as a ventriculoperitoneal (VP) or lumboperitoneal (LP) shunt, which diverts excess CSF from the brain or spine to another body cavity where it can be absorbed. Another procedure, venous sinus stenting, may be considered if a narrowing of the venous sinuses is identified, as this can relieve the blockage and improve blood outflow from the brain.