Types of Cerebrospinal Fluid (CSF) Leaks

What is a CSF leak?

The brain and spinal cord are protected by three membranes (meninges). When the outermost layer of the meninges, the dura, is injured or punctured — often as a result of a head injury, certain medical procedures, or increased pressure in the skull — a cerebrospinal fluid (CSF) leak may occur. Cerebrospinal fluid is a clear liquid that flows in and around the brain and spinal cord to protect them from injury and to transfer nutrients.

Types of CSF leaks

Cerebrospinal fluid leaks are categorized according to the location of the leak: A spinal CSF leak originates from the dura around the spinal column, whereas a cranial CSF leak originates from the dura around the skull. Spinal and cranial CSF leaks differ in symptoms, causes, and risk factors.

Spinal CSF leak

A spinal CSF leak can occur anywhere in the spinal column. A headache is the most common symptom of a spinal CSF leak.

Symptoms

Symptoms of a CSF leak headache include the following:

• Headache worsens when standing and improves when lying down.
• Headache pain is located in the back of the head.
• Headache worsens with coughing or straining.
• Although rare, the headache may start suddenly (“thunderclap” headache).

Other symptoms of a spinal CSF leak include the following:

• Nausea and/or vomiting
• Dizziness
• Neck and/or shoulder pain
• Tinnitus
• Vision changes
• Confusion
• Changes in behavior
• Changes in hearing

Causes

Potential causes of a spinal CSF leak include the following:

• Prior surgery on the spine
• Bone spurs along the spine
• Injury to the head or spine
• Irregularities of dura mater around the nerve roots in the spine
• Irregular connections between dura mater and veins (CSF-venous fistulas)
• Spinal tap procedure
• Epidural administration in the spine

Risk factors

Factors that increase the risk of a spinal CSF leak include the following:

• Previous spine surgery
• Connective tissue disorders such as Marfan syndrome or Ehlers-Danlos syndrome

Cranial CSF leaks

Cranial CSF leaks occur in the skull.

Symptoms

• Clear fluid that drains from one side of the nose or ear
• Hearing loss
• Metallic taste in mouth
• Meningitis

Causes

Potential causes of a cranial CSF leak include the following:

• Inner ear malformations
• Increased cranial pressure
• Head injury
• Sinus injury

Risk factors

Factors that increase the risk of a cranial CSF leak include the following:

• Irregularities of the base of the skull or inner ear
• Head trauma
• Previous cranial surgery
• Tumor at base of skull
• Sleep apnea