Homocystinuria presenting as sagittal sinus thrombosis

Familial pneumothorax: towards precision medicine

One in 10 patients suffering from primary spontaneous pneumothoraces has a family history of the disorder. Such familial pneumothoraces can occur in isolation, but can also be the presentation of serious genetic disorders with life-threatening vascular or cancerous complications. As the pneumothorax frequently precedes the more dangerous complications by many years, it provides an opportunity to intervene in a focused manner, permitting the practice of precision medicine. In this review, we will discuss the clinical manifestations and underlying biology of the genetic causes of familial pneumothorax.

Cerebral venous sinus thrombosis in homocystinuria: Dietary intervention in conjunction with anticoagulation

The presentation of cerebral venous sinus thrombosis may be acute or chronic with a progressive clinical course. The diagnosis can be challenging, and there are several clinical syndromes associated with the disease. It is also an uncommon but recognised complication of homocystinuria. We describe a case where early anticoagulation, together with dietary intervention, was associated with a favourable clinical outcome.

Risk factors for recurrent venous thromboembolism in the European collaborative paediatric database on cerebral venous thrombosis: a multicentre cohort study

Background

The relative importance of previous diagnosis and hereditary prothrombotic risk factors for cerebral venous thrombosis (CVT) in children in determining risk of a second cerebral or systemic venous thrombosis (VT), compared with other clinical, neuroimaging, and treatment variables, is unknown.

Methods

We followed up the survivors of 396 consecutively enrolled patients with CVT, aged newborn to 18 years (median 5·2 years) for a median of 36 months (maximum 85 months). In accordance with international treatment guidelines, 250 children (65%) received acute anticoagulation with unfractionated heparin or low-molecular weight heparin, followed by secondary anticoagulation prophylaxis with low-molecular weight heparin or warfarin in 165 (43%).

Results

Of 396 children enrolled, 12 died immediately and 22 (6%) had recurrent VT (13 cerebral; 3%) at a median of 6 months (range 0·1–85). Repeat venous imaging was available in 266 children. Recurrent VT only occurred in children whose first CVT was diagnosed after age 2 years; the underlying medical condition had no effect. In Cox regression analyses, non-administration of anticoagulant before relapse (hazard ratio [HR] 11·2 95% CI 3·4–37·0; p<0·0001), persistent occlusion on repeat venous imaging (4·1, 1·1–14·8; p=0·032), and heterozygosity for the G20210A mutation in factor II (4·3, 1·1–16·2; p=0·034) were independently associated with recurrent VT. Among patients who had recurrent VT, 70% (15) occurred within the 6 months after onset.

Conclusion

Age at CVT onset, non-administration of anticoagulation, persistent venous occlusion, and presence of G20210A mutation in factor II predict recurrent VT in children. Secondary prophylactic anticoagulation should be given on a patient-to-patient basis in children with newly identified CVT and at high risk of recurrent VT. Factors that affect recanalisation need further research.

Management and Prevention of Stroke Associated with Elevated Homocysteine

Observational data from prospective and retrospective studies indicate that elevated homocyst(e)ine (Hcy) is associated with preclinical markers of cerebrovascular disease and ischemic stroke. Although the exact mechanisms of this association are unresolved, data indicate that elevated Hcy promotes cerebral, arterial, and venous thrombosis, and may predispose to premature atherosclerosis and craniocervical arterial dissection. Plasma Hcy is a sensitive marker of low folate, B(12), and B(6) status. Data consistently indicate that folic acid supplementation in the form of vitamin tablets is the most effective strategy to lower mild-to-moderately elevated Hcy, with maximal benefit occurring in individuals with higher pretreatment Hcy or lower pretreatment folate levels. B(12) supplementation confers a minor additional benefit, whereas B(6) supplementation has not been demonstrated to confer further benefit. Despite reports that Hcy-lowering therapy may improve surrogate measures of vascular disease, the outcomes of clinical trials for secondary stroke prevention are pending. Until this information is available, we concur with the American Stroke Association guidelines for stroke prevention. Specifically, we recommend good dietary intake of foods rich in folic acid, B(6), and B(12) for primary prevention, and supplemental multivitamins (folic acid 400 g to 1 mg daily, B(12) 400 to 600 g daily, B(6) 2 to 10 mg daily) for individuals with known cerebrovascular disease and hyper-Hcy.

Trombose venosa cerebral e homocistinúria: relato de caso

Homocistinúria apresentando-se como trombose venosa cerebral é incomum. Relatamos o caso de um adolescente com características fenotípicas de homocistinúria que foi admitido por cefaléia intensa, vômitos e sonolência. Investigação diagnóstica com tomografia computadorizada de crânio, ressonância magnética e angiorressonância foi compatível com trombose dos seios transversos e sigmóides. Altos níveis de homocisteína foram detectados no sangue e na urina. Apresentamos os aspectos clínicos e radiológicos deste caso discutindo a controversa fisiopatologia da tendência trombofílica associada a homocistinúria.

Etiology of stroke in children

Although the risk factors for stroke in children are numerous and differ greatly from the causes of stroke in adults, a thorough diagnostic evaluation can identify one or more risk factors in most patients. Cardiac disorders and hemoglobinopathy are the most common causes of ischemic infarction, whereas various congenital anomalies of the blood vessels or defects in coagulation or platelet function are often found in children with intraparenchymal hemorrhage. More than one risk factor is commonly identified, especially in children with dural venous thrombosis. Identification of the underlying risk factors for cerebrovascular disorders in children is important because many of the risk factors can be treated, reducing the risk of subsequent strokes.

Homocysteine and cardiovascular disease: cause or effect?

Both markedly and mildly elevated circulating homocysteine concentrations are associated with increased risk of vascular occlusion. Here we review possible mechanisms that mediate these effects. Inborn errors of homocysteine metabolism result in markedly elevated plasma homocysteine (200-300 micromol/L) and thromboembolic (mainly venous) disease: treatment to lower but not to normalize these concentrations prevents vascular events. Mild homocysteine elevation (>15 micromol/L) occurs in approximately 20-30% of patients with atherosclerotic disease. Usually, this is easily normalized with oral folate and ongoing trials are assessing the effect of folate treatment on outcomes. Although there is evidence of endothelial dysfunction with both markedly and mildly elevated homocysteine concentrations, the elevated homocysteine concentration in atherosclerotic patients is also associated with most standard vascular risk factors, and importantly, with early decline in renal function, which is common in atherosclerosis. Decline in renal function alone causes elevated plasma homocysteine (and cysteine). These observations suggest that mild hyperhomocysteinemia could often be an effect rather than a cause of atherosclerotic disease. Data on the common C677T methylenetetrahydrofolate reductase polymorphism supports this, in that, although homozygosity is a frequent cause of mild hyperhomocysteinemia when plasma folate is below median population concentrations, it appears not to increase cardiovascular risk. Indeed, there is recent evidence suggesting an acute antioxidant effect of folic acid independent of its effect on homocysteine concentrations. This antioxidant mechanism may oppose an oxidant effect of homocysteine and be relevant to treatment of patients with vascular disease, especially those with chronic renal insufficiency. Such patients have moderately elevated plasma homocysteine and greatly increased cardiovascular risk that is largely unexplained.

Evaluation of hyperhomocysteinaemia in children with stroke

Hyperhomocysteinaemia is associated with an increased risk of arterial vascular disease and thrombosis in adults. Our aim was to study the association of hyperhomocysteinaemia and stroke in children. Since some patients who had suffered a stroke developed seizures and received treatment with anti-epileptic (antifolate) drugs, we also examined the possible interaction between anti-epileptic drugs and hyperhomocysteinaemia. Plasma total homocysteine was measured in 68 children with stroke (23 of the 68 were taking anti-epileptic drugs) and 100 children undergoing anti-epileptic treatment but without history of stroke, and we compared the values with our reference values for similar ages (n = 195). Total homocysteine was determined by high profile liquid chromatography with fluorescence detection. Hyperhomocysteinaemia was defined as a homocysteine concentration above the 95th percentile for the reference values. Significant differences were found in total homocysteine values of children with stroke and those taking anti-epileptic drugs compared with our reference values for similar ages, except for the adolescent group. Total homocysteine values above the 95th percentile for the reference values were found in 36% of patients with stroke and 28% of children on anti-epileptic treatment. Total homocysteine concentrations in the 23 patients with both stroke and anti-epileptic drug treatment were similar to those of untreated patients with stroke in all age groups. In summary, systematic screening for hyperhomocysteinaemia should be included in the protocol to investigate the aetiology of stroke, even in paediatrics. Anti-epileptic treatment in children with stroke may be responsible for the mild hyperhomocysteinaemia observed in some of them. A dietary supplement of folate may be of benefit in children with stroke and in patients taking anti-epileptic drugs.

Homocystinuria presenting as fatal common carotid artery occlusion

A patient with homocystinuria presenting with fatal cerebral infarction that resulted from left common carotid artery occlusion is reported. This 13-year-old, healthy and intelligent girl presented with progressive cerebral infarction. Angiography revealed total occlusion of the left common carotid artery and stenosis of the right common carotid artery. Distal stenosis of bilateral vertebral arteries was also observed. Initially Takayasu arteritis with unusual manifestation was considered. However, later investigations revealed homocystinuria was the underlying cause. The sudden onset of fatal stroke as the initial clinical presentation of homocystinuria, as observed in this previous healthy teenager, is noteworthy. We suggest metabolic screening for homocystinuria when treating a patient with unusual vascular lesions.

Discontinuation of anticonvulsant therapy in children free of seizures for 1 year: a prospective study

We studied 97 children who were weaned from antiepileptic drug therapy 1 year after their last seizure. Medication was withdrawn over 4 to 8 weeks, and patients were followed for 12 to 57 months (32.4 +/- 13.1; mean +/- SD) or until seizure recurrence. The overall probability of remaining seizure free was 78% at 3 months, 71% at 6 months, 66% at 12 months, and 61% at 24 months (95% CI, 51, 71), similar to studies that have required longer treatment periods. Factors retained in multivariate analysis were female sex, age at seizure onset over 120 months of age, seizure type, and clinical evidence of neurologic abnormalities. Using these risk factors, a simple method of predicting the 24-month recurrence risk was possible.

Hyperhomocysteinaemia; with reference to its neuroradiological aspects

Severe or even mild hyperhomocysteinaemia can cause a wide range of neurological problems. In recent years its vascular complications, including cerebral stroke, in children and young adults have gained special interest, because hyperhomocysteinaemia is treatable and recurrence of vascular incidents may be preventable. Current knowledge about biochemical mechanisms leading to hyperhomocysteinaemia, the pathogenesis of vascular pathology and neurological disfunction, and the various patterns of cerebral damage are reviewed. The significance of MRI in diagnosis, follow-up and research on hyperhomocysteinaemia is discussed.