most of the children with cerebral venous thrombosis have an underlying chronic disease and those who are previously well have an acute infectious illness . obstructive hydrocephalus as a complication of cerebral venous thrombosis is rare and few cases are described . a previously healthy 4-year - old boy presented with 5 days of headache and vomiting . magnetic resonance imaging of the patient revealed obstructive hydrocephalus and magnetic resonance venography revealed thrombosis of the right transverse sinus [ figure 1 ] . low molecular weight heparin was started at a dosage of 1 mg / kg twice a day . control magnetic resonance imaging and magnetic resonance venography 1 month after the first event revealed partial resolution of hydrocephalus along with recanalization of the affected sinus [ figure 2 ] . hydrocephalus and absent flow in the right transverse sinus showing acute thrombosis improvement of hydrocephalus and recanalization of the affected sinus after a month of heparin therapy with folic acid and vitamin b6 and b12 replacement , the follow - up of the patient was given up by the family and he did not receive any treatment for 5 months . six months after the first event , the patient was again admitted to hospital with a similar clinical picture along with new thrombosis at the sagittal sinus . the patient is still followed up with low molecular weight heparin treatment after the second thrombosis attack . cerebral venous system thrombosis is an unusual event in childhood and clinical presentations , complications , diagnostic procedures , etiological investigations , and treatment modalities were not well established . clinical findings of cerebral venous system thrombosis include seizures , headache , vomiting , drowsiness , lethargy , and confusion . the patient may show acute or subacute picture related to progression of the disease . the present case presented with acute symptoms secondary to increased intracranial pressure . increased intracranial pressure is a well - known complication of cerebral venous thrombosis , but accompanying hydrocephalus is rarely described . the mechanism of hydrocephalus is considered to be secondary to an increase in venous pressure resulting in the blockade of cerebrospinal fluid flow into the sinuses by arachnoid villi . most of the patients with cerebral venous thrombosis have an increased intracranial pressure without an increase in ventricular size . why some patients develop hydrocephalus is not clearly understood and only a few adult cases were described . the etiologies regarding cerebral venous thrombosis are diverse and include head and neck infections and chronic disorders such as collagen tissue disorders , cardiac disease , and hematological abnormalities . half of the patients have prothrombotic states which include anticardiolipin antibodies , deficiencies of protein c and s , antithrombin iii and prothrombotic gene mutations such as prothrombin 20210 , factor v leiden , and mthfr mutations . the most frequent two common mthfr polymorphisms are c677 t ( alanin to valin transition ) and a1298c ( glutamine to alanine transition ) . evaluation of nine case control studies with total 382 patients having cerebral venous thrombosis revealed that carrying mthfr was not a risk factor for cerebral venous thrombosis . on the contrary a canadian study revealed that 29% of patients with cerebral venous thrombosis had mthfr polymorphisms . our case had a prothrombotic state with mthfr 1298 homozygous polymorphism without any risk factors . occurrence of clinical findings after cessation of heparin treatment suggests that mthfr polymorphism may be an important risk factor for cerebral venous thrombosis . anticoagulation is not recommended for asymptomatic and hemorrhagic cases . when used , low molecular weight heparin is the standard anticoagulant treatment in children . treatment may last for 36 months or it may be continued until recanalization if risk factors are eliminated . our patient responded well to low molecular weight heparin with recanalization of sinuses and recovery of hydrocephalus in both the attacks . in conclusion mthfr 1298 polymorphism may be an important risk factor and low molecular weight heparin should be the choice of treatment in cases without hemorrhage .
cerebral venous thrombosis is a rare form of stroke in childhood . 
 increased intracranial pressure is a well - defined complication of cerebral venous thrombosis but obstructive hydrocephalus as a presentation finding of cerebral venous thrombosis is rarely described . a child case of cerebral sinus thrombosis presenting with obstructive hydrocephalus and management of clinical condition 
 is presented with discussion of reported cases and treatment recommendations .