Spontaneous Spinal Cerebrospinal Fluid Leaks: A Review

, Cedars-Sinai Neurosurgical Institute, Los Angeles, and Department of Neurosurgery, University of California, Irvine, California

Neurosurg Focus. 2000;9(1) 

In This Article

Causes and Pathogenesis

Spontaneous spinal CSF leaks are the most common cause of spontaneous intracranial hypotension.[70] Because these CSF leaks generally do not cause any other symptoms, they often remain undetected. Other causes of symptomatic spontaneous intracranial hypotension, such as spontaneous CSF rhinorrhea or otorrhea, diabetic coma, or uremia, are less common, and their diagnosis is usually straight forward because of the obvious associated symptomatology.

The exact cause of spontaneous spinal CSF leaks largely remains unknown, but an underlying weakness of the spinal meninges is generally suspected,[69,70,71,72,73] and a more or less trivial traumatic event often precedes the onset of symptoms (Table 1).[4,23,49,52,69] The structural dural weakness predisposes to the formation of fragile meningeal diverticula or simple dural rents that allow CSF to leak into the extradural space. There is good evidence to suggest that a generalized connective tissue disorder may play an important role in the development of spontaneous spinal CSF leaks and intracranial hypotension, as first reported in 1994.[72] In approximately one fifth of patients with spontaneous CSF leaks and intracranial hypotension, subtle skeletal abnormalities are commonly observed such as those seen in Marfan syndrome -- tall stature, joint hypermobility, and arachnodactyly -- but no other stigmata of the syndrome are found in these patients (Fig. 1).[70,72,73] In some of these patients an abnormality of fibrillin metabolism is expressed.[75] Another associated finding, suggesting the presence of a generalized connective tissue disorder, is the occurrence of spontaneous retinal detachment at an early age in patients with spontaneous CSF leaks.[70] Moreover, meningeal diverticula and spontaneous intracranial hypotension have been described in several well-characterized, generalized connective tissue disorders such as autosomal dominant polycystic kidney disease,[75] Marfan syndrome,[13,18,22] neurofibromatosis type 1,[17,42] and Lehman syndrome.[37,58]

Figure 1. Photograph showing a representative case of a generalized connective tissue disorder in spontaneous intracranial hypotension. Arachnodactyly and joint hypermobility were present in this 30-year-old woman with a spontaneous CSF leak at the thoracolumbar junction.

In rare circumstances spontaneous spinal CSF leaks are caused by an extradural pathological entity, such as a bone spur that pierces the dura.[16,83]

In the past, some authors have speculated that spontaneous intracranial hypotension results from decreased CSF secretion or generalized CSF hyperabsorption.[34,35,40,67,68] However, there are no data to support how these alternate mechanisms lead to a decrease in CSF pressure. Much remains to be learned about the pathophysiology of spontaneous intracranial hypotension, and a decrease in CSF volume, rather than in CSF pressure, may be the final common pathway.

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