Rare Presentation of Cerebral Venous Sinus Thrombosis in a Child.

Cerebral venous sinus thrombosis (CVST) is a critical condition with significant morbidity and mortality. It primarily affects the young and healthy. CVST presents a diagnostic challenge due to its varied presentation patterns. We report the case of a 11-year-old boy diagnosed with CVST after presenting with a long history of continuous headache. He improved following anticoagulation therapy. Despite thorough investigation, no discernible underlying cause could be identified.

INTRODUCTION

Thrombosis of the cerebral veins and sinuses is relatively uncommon and often misdiagnosed. Cerebral venous sinus thrombosis (CVST) occurs when a blood clot forms in the venous sinuses of the brain preventing blood from draining out of it. As a result, red blood cells may break and leak blood into the brain tissues, forming a hemorrhage, which results in raised intracranial pressure, toxic edema, seizures, and death. This process of events can occur in children and also in newborns. CVST is a rare form of stroke and the risk of stroke in newborns is greatest during the first month. Risk factors for children and infants include sickle cell anemia, chronic hemolytic anemia, β-thalassemia major, heart disease either congenital or acquired, iron deficiency, infections, dehydration, head injury, and coagulopathies.[123] CVST tends to be multifactorial in etiology, with estimates that up to 65% of patients with CVST had more than one risk factor.[234] Isolated headache without focal neurological findings or papilledema occurs in up to 25–40% of patients with CVST. Nearly 70–80% of all CVSTs are located in the superior sagittal sinus.[345] Availability of magnetic resonance venography (MRV) and Computed tomography (CT)-scan venography has made diagnosis of CVST easy without the need of invasive procedures. Here we report a young male child who presented with an acute headache that had not responded to routine conservative management.

CASE REPORT

An 11-year-old boy was brought to the hospital with complaints of severe headache and vomiting since 10 days. Headache was insidious in onset, of throbbing type, more in the temporal region, not relived on medication, and aggravated on exposure to light. Headache was associated with vomiting, which was projectile in nature, not preceded by nausea, consisting of food particles. There was no history of fever, diplopia, slurring speech, convulsion, visual disturbances, sinusitis, ear discharge, head injury, or any other neurological deficit. On probing further, the father reported that the boy had had spells of headache since 2 years. A private practitioner diagnosed the boy to suffer from migraine and was started on antimigraine prophylaxis (propranalol, flunarizine). Magnetic resonance imaging of the brain was done 6 months ago which was showed normal results. On admission patient was afebrile, irritable, and disoriented. Glasgow coma scale was 11/15 (E3, V3, M5), oxygen saturation was 98%, blood pressure was 100/64 mmHg, heart rate was 98 bpm, and respiratory rate was 20/min. On examination of the central nervous system, there was no muscle weakness, cranial nerves were intact, deep tendon reflexes were exaggerated, and babinski sign was positive. Other systemic examination revealed values within normal limits. Fundus examination was suggestive of the presence of papilledema. Routine blood tests for clotting, hemoglobin electrophoresis, and metabolic investigations showed normal results. Cerebrospinal fluid (CSF) examination also gave normal results and blood culture was sterile. Patient was managed conservatively.

CT scan of the brain was done which showed evidence of blood density collection in the right frontal region measuring 3.8 × 2.7 × 2.1 cm, with perilesional edema suggestive of intraparenchymal hemorrhage. Similar blood density collection in the left posterior parietal region measuring 1.9 × 1.4 × 1.0 cm was observed [Figure 1]. Also superior sagittal sinus straight and bilateral transverse sinus appear hypodense suggestive of thrombosis. MRV was done the following day which was suggestive of hemorrhagic infarct in the right high frontal, left posterior parietal region, and right frontal parafalcine location with dural venous sinus thrombosis in superior sagittal, inferior sagittal, transverse, and straight sinus [Figure 2]. A cerebral arteriogram showed normal results. A hypercoagulability workup performed which included factor V, prothrombin gene mutation, homocysteine, protein C and S, fibrinogen, anticardiolipin, and lupus screen were all negative. In addition, TSH, Free T3, Free T4, iron, serum ferritin, and TIBC were all negative. The chest X-ray And echocardiography showed normal results. The patient was started on low–molecular weight heparin (0.5 mg/kg/dose BD). A follow-up MRV was performed 8 days after diagnosis which showed improved flow of the cerebral venous sinuses. The patient reported a decrease in headache severity, which was an improvement from his chronic baseline state. He remained well and was discharged from hospital with no focal deficit.

Figure 1

CT scan of the brain showing intraparenchymal hemorrhage in the right frontal region and left posterior parietal region with perilesional edema

Figure 2

MRV of the brain showing venous sinus thrombosis in the superior sagittal, inferior sagittal, transverse, and straight sinus

DISCUSSION

CVST is relatively uncommon in children and is a rare form of venous thromboembolism with a reported rate of 0.67 per 100,000.[7] Venous drainage of the brain involves blood flow through cerebral veins into the dural sinuses that then drains into the internal jugular vein. Cerebral venous thrombosis therefore results from occlusion of a venous sinus and appears to be initiated by a partial thrombus or an extrinsic compression. Alternatively, the thrombus may extend to veins draining into the sinus. This causes cortical venous infarction with petechial or overt hemorrhagic, venous infarction, and regional ischemia.[8] As in our reported case, the superior and inferior sagittal sinus, transverse, and straight venous sinus were affected by thrombus. Two mechanisms are involved in the pathogenesis of CVST: localized edema and venous infarction due to cerebral vein occlusion and the development of raised intracranial pressure.

CVST is a multifactorial condition. The three main factors that predispose to clot formation are known as the Virchow triad, consisting of endothelial injury, stasis or turbulence of blood flow, and blood hypercoagulability. Hypercoagulable states are classified as either genetic or acquired. The known genetic causes include mutations in factor V, antithrombin III deficiency, protein C or S deficiency, fibrinolysis defects, homocysteinemia, and allelic variations in prothrombin levels. Acquired causes include prolonged immobilization, tissue damage, cancer, disseminated intravascular coagulation, heparin-induced thrombocytopenia, antiphospholipid antibody syndrome, atrial fibrillation, nephrotic syndrome, hyperestrogenic states, oral contraceptive use, sickle cell anemia, advancing age, and obesity. After formation, a clot will propagate, embolize, dissolve via fibrinolytic activity, or recanalize. The significance of a venous thrombus is dependent on its location, and detrimental effects are the result of congestion and edema in the vascular beds distal to the obstruction.[9101112] In patients who present with these risk factors, there is a high clinical suspicion of CVST. In neonates, shock and dehydration are common causes of venous thrombosis. In older children, it is often local infection, such as mastoiditis, coagulopathy, lupus, lymphoma, or leukemia.

Clinically patients present with variable symptoms ranging from headache to seizure and coma in severe cases. The common presenting symptom is headache that could be isolated in up to 5% of cases. Ferr et al.[13] reported that the common presentations were seizures (focal or generalized) and paresis in 40% of patients, papilledema in 30%, and visual loss in 13%. They also mentioned that mental status change and aphasia were reported in around 20% and 10%, respectively, of those who presented with coma. The commonly performed imaging during emergency is the CT scan of head. CT without contrast can reveal findings associated with CVST. The most common findings on noncontrast head CT scan is hyperdense triangular or round shape in the posterior superior sagittal sinus called the “dense triangle sign.” The “empty delta sign” seen with contrast-enhanced CT scan is a triangular ring of enhancement with a central region lacking contrast in the posterior superior sagittal sinus. CT or MRV venogram is the investigation of choice for CVST. A lack of flow in the cerebral veins consists of a positive venogram study.[91011] Routine blood investigation such as complete blood count, prothromin time, activated partial thromboplastin time, International Normalized Ratio (INR), factor V Leiden, protein C and S, and antithrombin III should be performed to identify any underlying prothrombotic state. CSF study is generally nonspecific, but may include a lymphocytic pleocytosis, elevated red blood cell count, and elevated protein.[1011] After extensive investigation, no underlying risk factors associated with CVST were demonstrated in our case.

The management consists of treating the underlying cause of the CVST with an anticoagulant such as heparin, enoxaparin, or warfarin. Heparin is a safe drug and effective in mortality reduction even in those with small parenchymal hemorrhages. Warfarin should be initiated in the inpatient setting and continued for at least 6 months with goal INR of 2–3. Our patient showed marked clinical and radiological improvement following administration. Patients with prothrombotic conditions may have to be on anticoagulation for life. Direct thrombolysis and thrombectomy in unstable/refractory patients was reported. Recanalization therapies using fibrinolytics or direct mechanical thrombectomy are another treatment modality. Earlier, the prognosis of CVST was very poor; however, most studies now show good outcomes. With newer treatment modalities, it is estimated that there is only a 5–10% mortality rate as a result of CVST. Also the predictors of increased mortality due to CVST are depressed consciousness, altered mental status, thrombosis of the deep venous system, right hemisphere hemorrhage, or posterior fossa lesions.[1213141516]

CONCLUSION

CVST is a challenging condition and clinicians should have a high degree of clinical suspicion about this condition. The symptoms and signs are varied, but most common ones are headache, raised intracranial hypertension, and papilledema. The use of imaging can help aid the diagnosis, with MR or CT venogram being important in detecting the occlusion. The antithrombotic treatment modalities include heparin, thrombolysis, and oral anticoagulants. Patients with prothrombotic conditions may require life-long therapy.

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