Cerebral Arteriovenous Malformations Causing Cerebrospinal Fluid Fistula
Bibliographic record
Abstract
Cerebral arteriovenous malformations (AVM) are congenital lesions in which arteries are connected to veins through an interposed nidus. 1 This aberrant vascular conglomerate acts as a high-flow and low pressure shunt between the feeding arteries and the draining veins thus creating an overload of the venous outflow from the lesion.2 Patients with AVMs become symptomatic through various manifestations, the most frequent being hemorrhage and seizures.Elevated intracranial pressure and papilledema are unusual modes of presentation which may be consequent to the venous outflow overload caused by the AVM. 2 A cerebrospinal fluid (CSF) fistula secondary to this phenomenon, however, has not been previously reported.The case presented herein concerns such an association. CASE REPORTA 23-year-old male with a history of cystic fibrosis and hepatic transplantation for which he had received immunosuppressive therapy for the last six years, notably cyclosporine, presented with de novo blurred vision and headache.For many years this patient had complained of a left-sided pulsatile tinnitus.The patient's general physical examination was normal and he had a body mass index of 20.7.A thorough neurological examination was normal except for bilateral papilledema without optic nerve dysfunction.Computed axial tomography scanning (CT-scan) and magnetic resonance imaging suggested an AVM (4 cm by 3 cm) without any significant mass effect or hydrocephalus (Figure 1).Four-vessel angiography confirmed it to be a right posterior temporal AVM supplied by the middle cerebral artery and to a lesser degree by the posterior cerebral artery.The nidus drained into the superficial temporal vein towards the junction between the ipsilateral transverse and sigmoid sinuses (Figure 2).This represents a grade 1 AVM on the Spetzler-Martin grading scale.Presumptive diagnosis was pseudotumor cerebri (PTC).Two causes were evoked: the AVM with its associated increased intracranial venous pressure, and the cyclosporine, which has been associated with PTC.3,4 Cystic fibrosis has also been associated with PTC as a result of hypervitaminosis or refeeding syndrome during correction of malnutrition, which was not the case in our patient.5,6 Because of the patient's comorbidities and the possibility that cyclosporine therapy may account for the PTC, the AVM was managed conservatively even though it was not excluded as causing the increased intracranial pressure.Owing to a series of lumbar punctures, with the opening pressure varying from 32 cm H 2 O to 46 cm H 2 O, the patient's condition evolved favourably and shunting was not deemed necessary.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.004 |
| Meta-epidemiology (narrow) | 0.002 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.004 | 0.003 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".