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Causes

Reviewed by Dr. Danny Adel Monsour, MD, FRCPC

Page last updated: May 2026

A spinal CSF leak stems from a tear or abnormality in the dura. A spinal CSF leak can occur unprovoked  (called spontaneous intracranial hypotension (SIH)), may happen as a result of certain medical procedures (called “iatrogenic”) or be caused by a sudden traumatic event.  

1. Spontaneous intracranial hypotension (SIH)

Common Causes of SIH

Nearly all diagnosed cases of spontaneous spinal CSF leaks fall into one of three categories.

  • Bone-Related Tears (Type 1 Leaks) Responsible for about 25–30% of cases. Degenerative changes in the spine, such as bone spurs or calcified discs, can puncture or erode through the dura and create a direct opening in the membrane.

  • Nerve Root Sleeve Weakness or Tears (Types 2 & 4 Leaks) Responsible for about 30–40% of cases. These leaks arise from weakness in the nerve root sleeves, which are small extensions of the dura surrounding each spinal nerve root. Pouch-like protrusions called meningeal diverticula can form at these weak points and eventually rupture.

  • CSF-Venous Fistulas (Type 3 Leaks) Also responsible for about 30–40% of cases. Rather than a hole in the dura, this is an abnormal connection between the spinal fluid space and a nearby vein. Spinal fluid is siphoned directly into the bloodstream instead of leaking into the space around the spine.

Less Common Causes

In a smaller number of patients, SIH stems from more specialized conditions:

  • Tarlov Cysts / Sacral Dural Tears: Fluid-filled cysts near the base of the spine that occasionally become a significant source of leakage.

  • Sacral Dural Ectasia: Abnormal widening or stretching of the dural sac in the lower spine.

  • CSF-Lymphatic Fistulas: A rare condition where spinal fluid drains into the lymphatic system rather than the venous circulation or the space surrounding the spine.

  • Connective Tissue Disorders: Conditions such as Ehlers-Danlos Syndrome (EDS) or Marfan Syndrome can result in structurally fragile dural tissue that is more prone to leaks and fistulas.

Some predisposing factors or inciting events linked to spontaneous intracranial include:

  • Valsalva maneuvers:

o   Heavy lifting

o   Protracted coughing

o   Vomiting

o   Constipation/straining

  • Repetitive truncal tortion/twisting

o   Tennis

o   Golf

o   Yoga

o   Pialtes

o   Kayaking

o   Canoeing

  • Other

o   Stretching

o   Intercourse

o   Chiropractic manipulation

o   Roller-coaster rides  

 

2. Medical Procedures (Iatrogenic)

  • Lumbar punctures, epidural catheter placement, and epidural injection. The resulting symptoms caused by unintentional dural puncture during epidural analgesia or intentional dural puncture for spinal anesthesia or for diagnostic or interventional neuraxial procedures are called Post Dural Puncture Headache (PDPH).  

  • Spinal surgery   

3. Trauma (caused by an injury)

  • Motor vehicle accident

  • Whiplash, sports-related injury

  • Falls

Key Notes

  • Some risk factors linked with a spontaneous intracranial hypotension include: Hereditary disorder of connective tissue (HDCT) such as Ehlers-Danlos syndrome, Marfan syndrome, Joint hypermobility; Spine Disorders such as Disc prolapse, Osteophytes and spondylotic spurs, Discogenic micro spurs, Dural weakness involving nerve root sleeves; Bariatric surgery.

  • Some experts believe that elevated pressure around the brain and spinal cord may have contributed to the leak in the first place, essentially forcing fluid through a weak point in the dura. This remains an area of active research and debate.

  • In many cases, PDPH is a self-limiting condition. However, in a subset of cases, PDPH can become chronic (cPDPH) or persistent (pPDPH).

  • After a confirmed dural puncture, for some patients, a structural change is developed, characterized by a small pseudo-meningocele or "bleb," which increases the risk of continuous cerebrospinal fluid (CSF) leakage.

  • Risks for PDPH can be mitigated by the routine use of noncutting (also called pencil-point or atraumatic) spinal needles, and, if using a cutting needle for an LP by using a smaller gauge needle 

References and suggested readings: