Extended Pneumocephalus after Drainage of Chronic Subdural Hematoma Associated with Intracranial Hypotension : Case Report with Pathophysiologic Consideration

Abstract

Chronic subdural hematoma (SDH) is a well-known disease entity and is traditionally managed with surgery. However, when associated with spontaneous intracranial hypotension (SIH), the treatment strategy ought to be modified, as classical treatment could lead to unwanted consequences. A 59-year-old man presented with a case of SIH that manifested as a bilateral chronic SDH. He developed fatal extensive pneumocephalus and SDH re-accumulation as a complication of burr-hole drainage. Despite application of an epidural blood patch, the spinal cerebrospinal fluid leak continued, which required open spinal surgery. Chronic SDH management should not be overlooked, especially if the exact cause has not been determined. When chronic SDH assumed to be associated with SIH, the neurosurgeon should determine the exact cause of SIH in order to effectively correct the cause.

Keywords: Chronic subdural hematoma; Intracranial hypotension; Pneumocephalus.

Fig. 1. Initial brain computed tomography obtained at admission showing a chronic subdural hemorrhage (arrowheads) over both cerebral hemispheres, which compressed the adjacent brain.

Fig. 2. Postoperative CT scans demonstrating extensive pneumocephalus in the subdural space in both the frontal areas, the subarachnoid space of both sylvian and the basal cistern. Note that a drainage catheter was placed over both the cerebral hemispheres (arrows) (A and B).

Fig. 3. Brain magnetic resonance imaging obtained 3 days after surgical drainage of the subdural hemorrhage. T2-wighted (A) axial image revealing re-accumulation of fluid content mixed with acute and chronic hemorrhage. T1-weighted sagittal image (B) showing sagging of the brain stem (asterisk).

Fig. 4. Radionuclide cisternography showing CSF leakage at the right distal sacral area (arrowhead) on the 3 hours image (A-D).

Fig. 5. Brain CT scans obtained 7 days after epidural blood patch demonstrating effacement of brain stem contour implying transtentorial herniation (A) and increased subdural hemorrhage (B).

Fig. 6. T2-weighted sagittal (A) and axial (B) magnetic resonance images of the lumbar spine revealing a large lobulating cystic lesion in the sacral canal and right sacral foramen at the S2-upper S3 level with a fistula (arrow), which is supposed to be CSF leaking site.

Fig. 7. Follow-up Brain CT scans 10 days after spine surgery showing restoration of brain stem contour (A) and reduced subdural hemorrhage (B).

Fig. 8. Schematic drawings showing the mechanism of extensive pneumocephalus development following burrhole drainage when spinal dural defect exist. A : Schematic drawing of the normal status of the body. B : When spinal dural defect exists, cerebrospinal fluid (CSF) leak into the epidural space, leading to lowering intracranial pressure. C : In the presence of drainage catheter connecting between the intracranial and outer space, air within the drainage cylinder may be drawn into the intracranial space; causing CSF to leak continuously, and, extensive pneumocephalus may finally be developed. Note that the drainage cylinder had a hole on top of the cylinder for the air flowing through.