CSF Leaks & Spontaneous
Intracranial Hypotension

What is spontaneous intracranial hypotension?

Spontaneous intracranial hypotension (SIH) is a condition caused by a spontaneous leak of cerebrospinal fluid (CSF) from the spinal column, most commonly through a small tear or defect in the spinal dural membrane. This reduces the CSF volume and pressure around the brain, causing the brain to sag downwards relative to the skull.

The condition is often underdiagnosed but is increasingly recognised as a cause of chronic, debilitating headache. It affects both men and women and can occur at any age, though it most commonly presents between 40 and 60 years.

Symptoms

The hallmark of SIH is an orthostatic headache — a headache that worsens markedly within minutes of sitting or standing, and improves when lying flat. This postural component is highly characteristic and should prompt further investigation. Other symptoms include:

• Neck stiffness and pain
• Nausea and vomiting
• Double vision or visual disturbance
• Tinnitus or hearing changes
• Cognitive difficulties — sometimes described as "brain fog"
• Upper limb symptoms — in cases of cervical CSF leaks

In some patients, particularly those with chronic leaks, the classical postural pattern may be lost over time, making diagnosis more challenging.

Causes

The most common causes of spinal CSF leaks include:

• Dural tear at a disc osteophyte complex — a calcified disc protrusion creates a ventral spinal dural tear, often at the thoracic level
• Meningeal diverticula — small outpouchings of the spinal dura that can rupture
• Dural weakness associated with connective tissue disorders — e.g. Marfan syndrome, Ehlers-Danlos syndrome
• Post-procedural leaks — following lumbar puncture, epidural anaesthesia, or spinal surgery

Diagnosis

Diagnosis begins with MRI of the brain, which may show characteristic features of brain sagging, pachymeningeal enhancement, subdural collections, and engorgement of the pituitary gland and cerebral venous sinuses. MRI of the spine may identify the leak site in some cases.

However, many leaks are not visible on standard MRI. Advanced imaging techniques — including CT myelography, digital subtraction myelography, and dynamic CT myelography — may be required to precisely localise the leak, particularly ventral dural tears.

Treatment

Management is staged according to severity and leak type:

• Conservative measures — bed rest, increased fluid and caffeine intake, abdominal binders; effective for mild cases
• Epidural blood patch (EBP) — injection of the patient's own blood into the epidural space to seal the leak; highly effective for post-procedural leaks and many spontaneous leaks
• Targeted blood or fibrin glue patch — delivered under fluoroscopic or CT guidance to the precise level of the leak; used when non-targeted patches fail
• CT-guided fibrin glue injection — for ventral dural tears at disc-osteophyte complexes, fibrin glue can be delivered transforaminally to the leak site
• Surgical dural repair — for accessible, clearly localised leaks that fail interventional treatment; performed by neurosurgery

Role of the neurointerventional radiologist

Precise leak localisation and targeted interventional treatment are central to the modern management of SIH. Our team works in close collaboration with neurology and neurosurgery colleagues to deliver a comprehensive pathway from initial diagnosis through to definitive treatment.

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