Pneumocephalus in Patients With Orthostatic Headache

Abstract

Cerebrospinal fluid (CSF) leak or shunt overdrainage is a well-known cause of orthostatic headaches and low CSF pressures. We report two cases of orthostatic headache with pneumocephalus on brain imaging. The orthostatic headache developed after drainage of spinal operation site and epidural block. Brain MRI revealed characteristic findings of CSF hypovolemia including pachymeningeal enhancement and mild subdural fluid collections. Air was also observed in the ventricular or subarachnoid space in both patients, which might enter the subarachnoid or ventricular space during a procedure via the pressure gradient or an injection. Characteristic MRI findings of spontaneous intracranial hypotension or intracranial hypotension following lumbar puncture are pachymeningeal enhancement, subdural fluid collections or subdural hematoma, engorgement of cerebral venous sinuses, enlargement of the pituitary gland, crowding of the posterior fossa, and a decrease in the size of the prepontine cisterns.1,2 These abnormalities have been explained by the Monro-Kellie doctrine, 3 whereby the summed volume of the brain, cerebrospinal fluid (CSF), and intracranial blood is nearly constant in an intact cranium. Therefore, the intracranial blood volume will be affected if CSF leakage occurs, resulting in a compensatory intracranial hyperemia that manifests as changes in brain MRI findings. We unexpectedly found intracranial air in patients complaining of orthostatic headache. Intracranial hypotension with orthostatic headache is a rare cause of pneumocephalus, 1,2 and here we report on these cases, including the imaging findings. CASE REPORTCase 1.A 75-year-old man with congestive heart failure and atrial fibrillation was transferred to our hospital for the management of dyspnea and coughing. A chest x-ray indicated pulmonary edema. He had received posterolateral fusion with pedicle screw fixation of L 4 and L 5 foramina 5 years previously. However, he suffered from sustained painful dysesthesia on the right leg and received follow-up decompression surgery for L 4 and L 5 foramina stenosis 2 days before admission to our hospital, during which the dura was torn and dural plasty was performed.On the 18 th hospital day at the Department of Internal Medicine he complained of nuchal discomfort with headache. Neurological deficits were not observed and the headache was not aggravated by

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Pneumocephalus secondary to a spinal surgery: A literature review and a case report

“…MRI can be decisive in the diagnosis of pneumocephalus but is less sensitive than CT scans, in some cases pneumocephalus can be difficult to diagnose as air may be mistaken as blood products or flow voids and appears black on both T1-weighted and T2-weighted sequences [30] , [31] , [32] . All reported cases of the review stated CT scanning as the main method for the conformation of pneumocephalus, some used MRI, and X-ray imaging as a second method of conformation.…”

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