Intracranial hypotension: iatrogenic

Case contributed by Dr Daniel Chow

Presentation

5-day postpartum patient presents with worsening headache and neck pain. Patient had a headache after delivery where a CTA was acquired but negative. Past medical history included an ACOM aneurysm which was coiled 10 years prior.

Patient Data

Age: 30 years
Gender: Female

ASNR 2016: This case was submitted as part of the American Society of Neuroradiology (ASNR 2016) Case Of The Day competition, in collaboration with Radiopaedia.org. 

Non-contrast Head CT from 5 days prior

CT

Axial noncontrast head CT acquired 5 days earlier (for comparison). There is no acute intracranial abnormality. Specifically, there is no acute hemorrhage, extra-cranial collection, or hydrocephalus.

Metallic artifact is present in the region of the ACOM, consistent with prior coiled aneurysm. Lucencies are present in the bifrontal white matter, which is related to prior shunt tracts.

Non-contrast Head CT at Presentation

CT

Axial non-contrast CT at presentation. There is a new left subdural hematoma overlying the left parietal convexity. Additionally, in comparison to the prior head CT, there is new increased prominence of the extra-axial spaces and the ventricular system is slightly decreased in prominence.

MR brain and thoracic spine images

MRI

Axial T2 images better demonstrate the prominent extra-axial spaces overlying the convexities bilaterally. Susceptibility artifact is seen overlying the right parietal convexity, which is related to known subdural hemorrhage. 

Sagittal images of the cervical, thoracic, and lumbar spine demonstrates a subdural collection extending from the cervicothoracic junction to the upper lumbar spine.

Intracranial images better demonstrate the prominent extra-axial spaces. Images of the spine demonstrates an extra-arachnoid CSF collection. Findings are consistent with presumed diagnosis of symptomatic CSF leak.

CT guided blood patch

CT

CT guided blood patch was targeted at the level of prior LP. Patient's headache improved over the next day.

Case Discussion

Intracranial hypotension results from decreased CSF pressure. While often spontaneous, secondary causes may result from trauma including lumbar puncture (either diagnostic or from anesthesia). In this case, acute intracranial hypotension resulting in a subdural hematoma is a rare complication following spinal anesthesia. In a review of 35 patients, risk factors included pregnancy, multiple punctures, use of anticoagulants, intracranial vascular abnormality, and cerebral atrophy. 

Clinically, these patients present with a characteristic orthostatic headache. Other common symptoms included nuchal pain (as in our patient), nausea, and vertigo.

MR imaging is diagnostic, and characteristic features include subdural hygromas and hematomas (as in our patient), distension of dural sinuses, and downward displacement of the midbrain. Post contrast images of the brain may demonstrate characteristic diffuse pachymeningeal enhancement. 

Therapeutically, radiologists may offer an epidural blood patch, which provides an immediate tamponade effect. For patients with large dural tears or clinical deterioration, surgical management is suggested.

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