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The aetiology of intracranial hypotension is not fully understood, but CSF leakage from spinal meningeal diverticula or dural tears may be involved. In the majority of patients without a history of mechanical opening of the dura the cause of intracranial hypotension is unknown and the syndrome is termed “spontaneous” intracranial hypotension. We report a case of intracranial hypotension ensuing after a spinal chiropractic manipulation leading to CSF isodense effusion in the upper cervical spine.
A 40 year old woman undertook a spinal chiropractic manipulation. The chiropractioner grasped the head of the supine patient and exerted axial tension while rotating the head. During this manoeuvre the patient complained of a sudden sharp pain in her upper neck, and the procedure had to be stopped immediately. Subsequently she complained of headaches and after 24 hours she developed nausea and vomiting. Her headaches worsened, and lying down gave the only measure of limited relief. On the sixth day she developed double vision and presented to the neurology department of a community hospital.
She had a right abducens palsy and pachymeningeal gadolinium enhancement on magnetic resonance imaging (MRI). The first working diagnosis was encephalomyelitis and steroids were given. Six days later a repeat lumbar puncture showed 60 cells per mm3 and raised lactate. The second working diagnosis was basal tuberculous meningitis and treatment with a antituberculous regimen was started. Another MRI was performed, and now showed bilateral subdural effusions. At this point blood leucocytosis was found and a subdural empyema was postulated as the third working diagnosis. The patient was referred to our neurosurgical university hospital for surgical evacuation and leptomeningeal biopsy.
On examination there were no signs of meningitis and apart from an incomplete right sixth nerve palsy the cranial nerves were intact. Neuropsychologically she was fully oriented but with slowed reactions. On general examination she showed no signs of a connective tissue disorder. All blood tests were within normal limits.
The diagnosis of intracranial hypotension was established by the typical clinical and radiological signs and antibiotics were stopped. On MRI a suspected CSF leak at the level of C1–C2 could be identified, with a CSF isodense fluid accumulation in the paravertebral soft tissue and musculature (fig 1). MRI of the complete spinal axis revealed no additional site of CSF leakage. The patient was discharged home and her symptoms resolved gradually over several weeks. A high resolution CISS-MRI of the upper cervical spine eight weeks after discharge no longer showed a CSF isodense effusion and there was no additional underlying pathology.
The aetiology of spontaneous intracranial hypotension is unknown. Mechanical disruption of the spinal dural thecal sac with subsequent loss of CSF seems to be the major pathophysiological mechanism. Spinal meningeal tears are thought generally to be spontaneous. There are structural abnormalities related to the syndrome of intracranial hypotension which include spinal meningeal diverticula or Tarlov cysts. It has been shown that some cases of spontaneous intracranial hypotension are associated with microfibrillopathy in the context of a connective tissue disorder.1,2 Jeret reported one case of a presumed spinal dural tear after chiropractic manipulation, though there was neither dural contrast enhancement nor evidence of a CSF leak.3
To our knowledge, this is the first case of a patient presenting with “spontaneous” intracranial hypotension in whom spinal chiropractic manipulation coincided with the development of symptoms, and where a CSF isodense fluid collection in the upper cervical spine was demonstrated radiographically. Neither an underlying meningeal diverticulum nor any other anatomical abnormality could be detected on repeated MRI, including a CISS sequence. Furthermore MRI of the complete spinal axis did not reveal any other site of CSF loss. This suggests that a dural tear in this region was the cause of the intracranial hypotension. We think this is more likely than the interesting alternative concept suggested by Yousry et al,4 that CSF loss from another site in the dural sac may be followed by a CSF isodense effusion in the C1–C2 region, caused by exudation or transudation from the paraspinal venous plexus.
In a series of 30 patients with intracranial hypotension, Chung et al reported one who had also undergone spinal chiropractic manipulation.5 A spinal CSF leak could not, however, be identified. In their study, thorough history taking in all the patients revealed risk factors for a possible traumatic origin of intracranial hypovolaemia in seven of the 30 patients, including playing golf, vigorous physical activity, swimming, yoga exercise, and upper respiratory infections with severe cough.
Trauma, even if mild, may be a risk factor and may account for a substantial proportion of patients with “spontaneous” intracranial hypotension. Our case shows that spinal chiropractic manipulation can lead to intracranial hypotension. History taking should include a thorough inquiry about trauma, with a special emphasis on chiropractic manoeuvres and mild traumatic events. The syndrome of intracranial hypotension must be added to the list of differential diagnoses in cases of subdural effusion or meningeal enhancement because of the favourable outcome with conservative treatment. A substantial number of unhelpful meningeal biopsies and empiric intravenous courses of antibiotic drugs may be avoided by considering this syndrome in the differential diagnosis.
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