Neurology
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A 35 year old woman presents to ED with a gradual onset severe headache, preceded by a generalised seizure which terminated after 2 minutes. She recently gave birth by normal vaginal delivery 2 weeks ago and has no other significant past medical history. On examination, she has weakness and altered sensation to her left arm only. What is the most likely diagnosis?
Answer:
Cerebral venous sinus thrombosis has a highly variable clinical presentation. The clinical symptoms and signs in CVST depend upon several factors, including patient age and sex, the site and number of occluded sinuses and veins, the presence of parenchymal brain lesions, and the interval from CVST onset to presentation. Headache is the most frequent symptom and is typically characterised by severe head pain that worsens with Valsalva maneuvers and with recumbency. Headache onset with CVST is usually gradual, increasing over several days.Cerebral Venous Sinus Thrombosis
Neurology
Last Updated: 12th February 2021
Cerebral venous sinus thrombosis (CVST) is less common than most other types of stroke but can be more challenging to diagnose.
Pathophysiology
Thrombosis of cerebral veins or dural sinus obstructs blood drainage from brain tissue, leading to cerebral parenchymal lesions (e.g. stroke) or dysfunction, and to increased venous and capillary pressure with disruption of the blood-brain barrier, causing vasogenic oedema, with leakage of blood plasma into the interstitial space. As intravenous pressure continues to increase, localised cerebral oedema and venous haemorrhage may occur due to venous or capillary rupture. The increased intravenous pressure may lead to an increase in intravascular pressure and a lowering of cerebral perfusion pressure, resulting in decreased cerebral blood flow (CBF) and failure of energy metabolism. Occlusion of dural sinus also results in decreased cerebrospinal fluid (CSF) absorption and elevated intracranial pressure.
Risk factors
The most frequent risk factors for CVST are:
- Prothrombotic conditions, either genetic or acquired
- Oral contraceptives
- Pregnancy and the puerperium
- Malignancy
- Infection e.g. CNS infection, ear, sinus, mouth, face and neck infection, systemic infectious disease
- Head injury and mechanical precipitants e.g. neurosurgical procedures
- Inflammatory disease e.g. SLE, Behçet disease
In more than 85 percent of adult patients, at least one risk factor for CVST can be identified, most often a prothrombotic condition.
Clinical features
Cerebral venous sinus thrombosis has a highly variable clinical presentation. The clinical symptoms and signs in CVST depend upon several factors, including patient age and sex, the site and number of occluded sinuses and veins, the presence of parenchymal brain lesions, and the interval from CVST onset to presentation.
Headache is the most frequent symptom and is typically characterised by severe head pain that worsens with Valsalva maneuvers and with recumbency. Headache onset with CVST is usually gradual, increasing over several days. However, some patients with CVST have sudden explosive onset of severe head pain (i.e. thunderclap headache) that mimics subarachnoid hemorrhage.
Symptoms and signs of CVST can be grouped into three major syndromes:
- Isolated intracranial hypertension syndrome (headache with or without vomiting, papilloedema, and visual problems)
- Focal syndrome (focal deficits e.g. weakness with monoparesis or hemiparesis or aphasia, seizures, or both)
- Encephalopathy (multifocal signs, mental status changes, stupor, or coma)
Isolated thrombosis of the different sinuses and veins produces diverse clinical pictures, for example, in cavernous sinus thrombosis, ocular signs dominate the clinical picture with orbital pain, chemosis, proptosis, and oculomotor palsies.
Diagnosis
In patients with clinically suspected CVST urgent neuroimaging is necessary as the first step in the diagnostic evaluation. Brain magnetic resonance imaging (MRI) in combination with magnetic resonance venography is the most informative technique for demonstrating the presence of dural thrombus, cortical vein thrombosis, and extent of brain injury. Head computed tomography (CT) scan is normal in up to 30 percent of CVST cases, and most of the findings with CVST are nonspecific.
The neuroimaging features of CVST can include focal areas of oedema or venous infarction, haemorrhagic venous infarction, diffuse brain oedema, or (rarely) isolated subarachnoid hemorrhage. The clear demonstration of absence of flow and intraluminal venous thrombus by CT or MRI is the most important finding for confirming the diagnosis. However, these findings are not always evident, and the diagnosis may rest on imaging features demonstrated by MR venography or CT venography showing only absence of flow in a venous sinus or cortical vein.
Screening for thrombophilia should be done for patients with CVST who have a high pretest probability for severe thrombophilia, a category that includes those with a personal and/or family history of venous thrombosis, CVST at a young age, and CVST in the absence of a transient or permanent risk factor.
Management
Treatment, which is started as soon as the diagnosis is confirmed, consists of reversing the underlying cause when known, control of seizures and intracranial hypertension, and antithrombotic therapy. Anticoagulation is the mainstay of acute and subacute treatment for CVT, using either heparin or low molecular weight heparin (LMWH) initially, followed by long-term anticoagulation with e.g. warfarin or dabigatran.
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
