Spontaneous intracranial hypotension complicated by diffuse cerebral edema and episodes of severely elevated intracranial pressure: illustrative case

BACKGROUND Spontaneous intracranial hypotension (SIH) is a well-documented condition that typically follows a defined clinical course. Previously published studies describing the pathophysiology of SIH have demonstrated extensive evidence of low intracranial pressure (ICP) driving the clinical features of the condition. Through lumbar puncture and use of intracranial monitoring devices, however, both low and normal cerebrospinal fluid (CSF) pressures have been documented. This report outlined and discussed the unique finding of elevated ICP associated with clinical features of SIH. OBSERVATIONS Here, the authors presented a case of a patient with spontaneous spinal CSF leak who developed tonsillar herniation, cerebral edema, and subsequent episodes of elevated ICP. Although more diverse presentations of SIH are being reported, the authors believed the case to be unique because SIH was accompanied by elevated ICP. LESSONS This case adds to the growing body of literature surrounding SIH by demonstrating that patients can develop elevated CSF pressures associated with acute encephalopathy.

Complete posterior cranial vault distraction osteogenesis to correct Chiari malformation type I associated with craniosynostosis

OBJECTIVE Posterior vault distraction osteogenesis (PVDO) is an effective tool to increase intracranial volume and expand the posterior cranial fossa. During PVDO, the authors extended osteotomy posterior to the foramen magnum to fully expand the posterior cranial fossa. The aim of this study was to investigate the efficacy of complete PVDO in posterior fossa expansion and treatment of Chiari malformation type I (CM-I) in patients with craniosynostosis. METHODS Patients with craniosynostosis who had undergone complete PVDO between January 2012 and May 2020 were reviewed retrospectively. A coronal osteotomy extending to the foramen magnum was performed and the foramen magnum was decompressed by removing its posterior rim with a 1-mm Kerrison rongeur. Four distractor devices were placed and the vector of distraction was controlled from the posterior to the inferior-posterior direction, depending on the deformity. Changes in the intracranial volume, posterior cranial fossa area, and cerebellar tonsillar descent were measured after complete PVDO by using CT and MRI. RESULTS A total of 11 patients with craniosynostosis and concurrent CM-I were included in the study. The mean age was 34.6 ± 24.0 months (continuous variables are expressed as the mean ± SD throughout). One patient had sleep apnea, which was consistent with CM-I, and another patient had a headache, which was nonspecific. The intracranial volume increased from 1179.6 ± 180.2 cm3 to 1440.6 ± 251.5 cm3 (p = 0.003; 24.5% increase compared to the preoperative volume). The posterior skull base area increased from 44.9 ± 19.3 cm2 to 72.7 ± 18.1 cm2 (p = 0.004). Cerebellar tonsillar descent decreased in all 11 patients after complete PVDO (preoperative: 10.8 ± 3.7 mm, postoperative: 2.7 ± 3.0 mm; p = 0.003). Among the 11 patients, 5 showed complete resolution of cerebellar tonsillar herniation. CONCLUSIONS Complete PVDO can more efficiently expand the posterior cranial fossa, unlike conventional methods. Moreover, it helps to relieve cerebellar tonsillar herniation. Complete PVDO is a powerful tool to increase the intracranial and posterior fossa volumes in patients with craniosynostosis and concurrent CM-I.

Posterior Cranial Fossa Meningioma Causing Tonsillar Herniation and Giant Cervicothoracic Syringomyelia, Case Report and Review of Literature

Background Syringomyelia is a fluid-filled cyst within the spinal cord and usually associated with Arnold-Chiari malformation. Posterior cranial fossa tumours are a rare cause of tonsillar herniation and secondary syringomyelia. Case Presentation: We report a rare case of a 56-year-old female with posterior cranial meningioma and secondary syringomyelia, admitted with headache, nausea, vomiting, and ataxic gait. MRI demonstrated a large posterior fossa lesion causing early ventriculomegaly and syrinx within the upper spinal cord extending from the hindbrain inferiorly to the level of T8. She underwent a posterior fossa craniectomy with left C1 hemilaminectomy and complete excision of the tumour. In 6 months following her procedure, MRI scan showed a significant reduction in the calibre of the syringomyelia throughout its length and there was a significant improvement in symptoms. Literature review: A PubMed literature search was carried out with keywords: “syringomyelia”, “posterior fossa” and “tumour”. 120 articles were reviewed. The inclusion criteria for this study was posterior fossa meningioma causing syrinx formation. A total of 9 isolated similar cases were identified. Discussion Tonsillar herniation and syringomyelia secondary to posterior cranial fossa meningioma are rare. The alteration in the dynamic flow of CSF is likely to be the cause for the formation and enlargement of the syrinx. Conclusion Although the pathophysiology of syrinx formation is still poorly understood, the alteration of CSF dynamic has been implicated, but a common unifying cause appears to be increased transcranial difference in intracranial pressure across the foramen magnum causing tonsillar herniation, irrespective of location in the posterior fossa. Posterior fossa craniotomy and excision of the lesion is the mainstay treatment.

Cerebellar Tonsillar Herniation in Sudden Death of An Adolescent Anorexia Nervosa Patient: A Case Report.

Background: Anorexia nervosa not only results in severe malnutrition but also carries a high risk of sudden death. Although fatal arrhythmias are the most common cause of sudden death, it is often unclear what exactly causes them. To the best of our knowledge, there have been no reports of cerebral herniations in patients with anorexia nervosa.Case presentation: A 17-year-old adolescent girl with neuropathy and autism spectrum disorder was admitted to the pediatric ward for extreme weight loss. Eight hours after admission, she suddenly went into cardiopulmonary arrest and died despite resuscitation. A postmortem autopsy revealed the unexpected findings of generalized severe cerebral edema and cerebellar tonsillar herniation.Conclusion: Intracranial hypertension may need to be considered when the condition of patients with anorexia nervosa suddenly worsens during refeeding periods. Postmortem autopsy and autopsy imaging are recommended to determine the exact cause of sudden death.

Diagnostic utility of parasagittal measurements of tonsillar herniation in Chiari I malformation

Background and purpose Although the cerebellar tonsils are parasagittal structures, the extent of tonsillar herniation (ETH) in Chiari I malformation (CMI) is currently measured in the midsagittal plane. We measured the ETH of each cerebellar tonsil in the parasagittal plane and assessed their diagnostic utility by comparing them to the midsagittal ETH measurements in predicting cough-associated headache (CAH), an indicator of clinically significant disease in CMI. Methods Eighty-five CMI patients with 3D-MPRAGE images were included. Neurosurgeons determined the presence of CAH. Sagittal images were used to measure ETH in the midsagittal (MS_ETH) and parasagittal planes (by locating tonsillar tips on each side on reformatted coronal images). Given the parasagittal ETH (PS_ETH) asymmetry in the majority of cases, they were considered Smaller_PS_ETH or Larger_PS_ETH. The accuracy of ETH measurements was assessed by the receiver operating characteristic (ROC) curve. Results Of 85 patients, 46 reported CAH. ROC analysis showed an area under the curve (AUC) of 0.78 for Smaller_PS_ETH significantly better than 0.65 for MS-ETH in predicting CAH ( p = 0.001). An AUC of 0.68 for Larger_PS_ETH was not significantly different from MS_ETH. The sensitivity and specificity of predicting CAH were 87% and 28% for MS_ETH >6 mm versus 90% and 46% for Smaller_PS_ETH >6 mm, and 52% and 67% for MS_ETH >9 mm versus 48% and 87% for Smaller_PS_ETH >9 mm. At ETH >15 mm, no differences were seen between the measurements. Conclusions Diagnostic utility of ETH measurements in detecting clinically significant CMI can be improved by parasagittal measurements of the cerebellar tonsillar herniation.

Fourth ventricle roof angle as a measure of fourth ventricle bowing and a radiographic predictor of brainstem dysfunction in Chiari malformation type I

OBJECTIVE Chiari malformation type I (CM-I) is a congenital and developmental abnormality that results in tonsillar descent 5 mm below the foramen magnum. However, this cutoff value has poor specificity as a predictor of clinical severity. Therefore, the authors sought to identify a novel radiographic marker predictive of clinical severity to assist in the management of patients with CM-I. METHODS The authors retrospectively reviewed 102 symptomatic CM-I (sCM-I) patients and compared them to 60 age-matched normal healthy controls and 30 asymptomatic CM-I (aCM-I) patients. The authors used the fourth ventricle roof angle (FVRA) to identify fourth ventricle “bowing,” a configuration change suggestive of fourth ventricle outlet obstruction, and compared these results across all three cohorts. A receiver operating characteristic (ROC) curve was used to identify a predictive cutoff for brainstem dysfunction. Binary logistic regression was used to determine whether bowing of the fourth ventricle was more predictive of brainstem dysfunction than tonsillar descent, clival canal angle, or obex position in aCM-I and sCM-I patients. RESULTS The FVRA had excellent interrater reliability (intraclass correlation 0.930, 95% CI 0.905–0.949, Spearman r2 = 0.766, p < 0.0001). The FVRA was significantly greater in the sCM-I group than the aCM-I and healthy control groups (59.3° vs 41.8° vs 45.2°, p < 0.0001). No difference was observed between aCM-I patients and healthy controls (p = 0.347). ROC analysis indicated that an FVRA of 65° had a specificity of 93% and a sensitivity of 50%, with a positive predictive value of 76% for brainstem dysfunction. FVRA > 65° was more predictive of brainstem dysfunction (OR 5.058, 95% CI 1.845–13.865, p = 0.002) than tonsillar herniation > 10 mm (OR 2.564, 95% CI 1.050–6.258, p = 0.039), although increasing age was also associated with brainstem dysfunction (OR 1.045, 95% CI 1.011–1.080, p = 0.009). A clival canal angle < 140° (p = 0.793) and obex below the foramen magnum (p = 0.563) had no association with brainstem dysfunction. CONCLUSIONS The authors identified a novel radiographic measure, the FVRA, that can be used to assess fourth ventricular bowing in CM-I and is more predictive of brainstem dysfunction than tonsillar herniation. The FVRA is easy to measure, has excellent interrater variability, and can be a reliable universal radiographic measure. The FVRA will be useful in further describing CM-I radiographically and clinically by identifying patients more likely to be symptomatic as a result of brainstem dysfunction.

A RARE CASE MORTALITY OF DIABETIC KETOACIDOSIS- CEREBRAL EDEMA WITH TONSILLAR HERNIATION- A CONTRADICTORY OPINION.IS SODIUM BICARBONATE A REAL CULPRIT?

Diabetic ketoacidosis (DKA) is the most common complication seen in uncontrolled diabetes mellitus. DKA is most commonly seen with patients of type 1 diabetes. Depletion of Insulin leads to high blood sugars which in turn leads osmotic diuresis, production of ketone bodies i.e, βhydroxybutyric acid and acetoacetic acid, dysregulation of sodium hydrogen exchange mechanism[2]. As a consequence to the above stated mechanisms, cerebral edema has been documented as a fatal complication in DKA. Mortality documented due to cerebral edema is 21-25%[4].