Acquired and reversible Chiari-like descent following a single lumbar puncture: case report

Medullary Infarction Leading to Locked-In Syndrome Following Lumbar Puncture in a Patient with Basilar Invagination

BACKGROUND

Lumbar puncture is a common procedure that can be safely performed in most patients. Certain populations may have increased risk for complications following lumbar puncture, but the significance of basilar invagination is often underappreciated.

CASE DESCRIPTION

A 45-year-old woman with basilar invagination received multiple lumbar punctures in the workup of acute meningitis. Preprocedural computed tomography was obtained. Following lumbar puncture, the patient developed locked-in syndrome. Magnetic resonance imaging obtained several days later demonstrated severe compression and infarction of the medulla and inferior cerebellum by the odontoid process and ectopic cerebellar tonsils. The patient was transferred but at this point, surgical decompression was not possible. She did not regain significant neurologic function.

CONCLUSIONS

Basilar invagination is a risk factor for devastating neurologic complications following lumbar puncture. Awareness of this complication and prompt recognition of its occurrence may prevent future morbidity of lumbar puncture in patients with basilar invagination.

Quantifying response to intracranial pressure normalization in idiopathic intracranial hypertension via dynamic neuroimaging

BACKGROUND

Idiopathic intracranial hypertension (IIH) is characterized by elevated intracranial pressure without a clear cause.

PURPOSE

To investigate dynamic imaging findings in IIH and their relation to mechanisms underlying intracranial pressure normalization.

STUDY TYPE

Prospective.

POPULATION

Eighteen IIH patients and 30 healthy controls.

FIELD STRENGTH/SEQUENCE

T₁ -weighted, venography, fluid attenuation inversion recovery, and apparent diffusion coefficients were acquired on 1.5T scanner.

ASSESSMENT

The dural sinus was measured before and after lumbar puncture (LP). The degree of sinus occlusion was evaluated, based on 95% confidence intervals of controls. We studied a number of neuroimaging biomarkers associated with IIH (sinus occlusion; optic nerve; distribution of cerebrospinal fluid into the subarachnoid space, sulci and lateral ventricles (LVs); Meckel's caves; arachnoid granulation; pituitary and choroid plexus), before and after LP, using a set of specially developed quantification techniques.

STATISTICAL TESTS

Relationships among various biomarkers were investigated (Pearson correlation coefficient) and linked to long-term disease outcomes (logistic regression). The t-test and the Wilcoxon rank test were used to compare between controls and before and after LP data.

RESULTS

As a result of LP, the following were found to be in good accordance with the opening pressure: relative compression of cerebrospinal fluid (R = -0.857, P < 0.001) and brain volumes (R = -0.576, P = 0.012), LV expansion (R = 0.772, P < 0.001) and venous volume (R = 0.696, P = 0.001), enlargement of the pituitary (R = 0.640, P = 0.023), and shrinkage of subarachnoid space (R = -0.887, P < 0.001). The only parameter that had an impact on long-term prognosis was cross-sectional size of supplemental drainage veins after LP (sensitivity of 92%, specificity of 20%, and area under the curve of 0.845, P < 0.001).

DATA CONCLUSION

We present an approach for quantitative characterization of the intracranial venous system and its implementation as a diagnostic assistance tool. We conclude that formation of supplementary drainage veins might serve as a long-lasting compensatory mechanism.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:913-927.

Acute Foramen Magnum Syndrome Following Single Diagnostic Lumbar Puncture: Consequence of a Small Posterior Fossa?

BACKGROUND

Type I Chiari malformation (CMI) is a rare complication of lumbar cerebrospinal fluid (CSF) drainage that is usually reported after lumbar drain or lumboperitoneal shunt placement. It usually remains asymptomatic; however, even if it becomes symptomatic, symptoms are usually mild. There are only a few reports of acute foramen magnum syndrome following continuous lumbar CSF drainage, and acute foramen magnum syndrome after a single diagnostic lumbar puncture (LP) has not been previously reported. We encountered this catastrophic complication in one of our patient.

CASE DESCRIPTION

A 30-year-old woman with a large supratentorial meningioma and associated asymptomatic CMI presented with holocranial headache. She underwent successful and uneventful excision of the tumor. However, she developed quadriplegia and respiratory arrest 48 hours following a diagnostic LP performed on postoperative day 9. She underwent urgent posterior fossa decompression after magnetic resonance imaging showed increased tonsillar impaction and swelling along with cervicomedullary compression. Postoperatively, she steadily improved and regained normal power after 3 months. Retrospective quantitative analysis of magnetic resonance imaging (MRI) revealed a small posterior fossa.

CONCLUSIONS

The association of intracranial tumors and lumbar CSF drainage with CMI is uncommon. The documentation of a small posterior fossa signifies the importance of both developmental (small posterior fossa) and acquired (intracranial tumor/lumbar CSF drainage) factors in pathogenesis of CMI. Although the extreme rarity of acute deterioration following a single LP does not warrant LP to be contraindicated in such patients, documentation of resolution of CMI with postoperative MRI before performing lumbar CSF drainage (whether therapeutic or diagnostic), might be helpful in avoiding this rare complication.

Acquired Chiari malformation type I associated with a supratentorial fistulous arteriovenous malformation: a case report

A case of acquired Chiari malformation type I with frontal fistulous arteriovenous malformation (AVM) is presented, and the pathophysiology is discussed. The tonsillar herniation and hydrocephalus both resolved after AVM was excised. This case provides some insight into the complex hemodynamic change exerted by the fistulous AVM and the mechanism of the development of acquired Chiari malformation type I.