Homocystinuria presenting as fatal common carotid artery occlusion

Angiopathy and Stroke Associated with Homocystinuria in Childhood

A previously healthy 13 year-old boy presented with acute-onset headaches, aphasia and right-sided hemiparesis. Imaging showed cerebral ischemic infarction due to bilateral carotid occlusion, and investigation for stroke etiology diagnosed homocystinuria. Homocystinuria is an autosomal recessive condition that affects the metabolism of the amino acid methionine due to an enzyme deficiency. This disorder involves multiple organs systems, and complications include thromboembolic events, ectopia lentis, mental retardation, and skeletal abnormalities. The early diagnosis and treatment of hyperhomocystinemia can significantly improve outcomes. Therefore, metabolic screening for homocystinuria is strongly recommended for children presenting with stroke.

Homocystinuria with Stroke and Positive Familial History

Homocystinuria is the second most common treatable aminoacidopathy. Clinically, affected patients present with eye, skeleton, central nervous system, and most importantly, vascular system abnormalities. This autosomal recessive disorder leads to accumulation of homocysteine and its metabolites in the blood and urine. In this report, we present a case with clinical and biochemical findings of homocystinuria with stroke and a positive familial history of the disease in her brother. A 4-year-old girl was admitted to pediatric emergency ward because of acute onset of right hemiparesis and subsequent generalized tonic–clonic seizures. Cranial magnetic resonance imaging revealed acute infarct areas in the left cerebral hemisphere. Metabolic screening revealed elevated concentrations of serum homocysteine and methionine and a normal serum concentration of vitamin B12. These findings, along with a positive familial history led to the diagnosis of homocystinuria. In any child who presents with stroke, some rare condition such as homocystinuria should be considered in diagnosis.

Metabolic profiling of total homocysteine and related compounds in hyperhomocysteinemia: utility and limitations in diagnosing the cause of puzzling thrombophilia in a family

We describe a family illustrating the diagnostic difficulties occurring when pyridoxine-responsive cystathionine beta-synthase (CBS) deficiency presents with thrombotic disease without associated ocular, skeletal, or CNS abnormalities, a situation increasingly recognized. This family had several thromboembolic episodes in two generations with apparently inconstant elevations of plasma total homocysteine (tHcy). When taking (sometimes even low amounts) of pyridoxine, the affected family members had low-normal tHcy and normal values for cystathionine, methionine, and cysteine. Withdrawal of vitamin therapy was necessary before lower cystathionine, elevated methionine, and decreased cysteine became apparent, a pattern suggestive of CBS deficiency, leading to the finding that the affected members were each compound heterozygotes for CBS p.G307S and p.P49L. To assist more accurate diagnosis of adults presenting with thrombophilia found to have elevated tHcy, the patterns of methionine-related metabolites in CBS-deficient patients are compared in this article to those in patients with homocysteine remethylation defects, including inborn errors of folate or cobalamin metabolism, and untreated severe cobalamin or folate deficiency. Usually serum cystathionine is low in subjects with CBS deficiency and elevated in those with remethylation defects. S-Adenosylmethionine and S-adenosylhomocysteine are often markedly elevated in CBS deficiency when tHcy is above 100 umol/L. We conclude that there are likely other undiagnosed, highly B6-responsive adult patients with CBS deficiency, and that additional testing of cystathionine, total cysteine, methionine, and S-adenosylmethionine will be helpful in diagnosing them correctly and distinguishing CBS deficiency from remethylation defects.

Stroke in early childhood due to homocystinuria

A previously healthy girl, age 3 years 9 months, presented with right-sided hemiparesis and seizures. Ischemic infarction was confirmed through magnetic resonance imaging and magnetic resonance angiography. Extensive evaluation to discover the underlying etiologies and risk factors predisposing this patient to stroke included coagulation defects, cardiac anomalies, congenital inborn metabolism deficiency, and infections and trauma. Based on the clinical and laboratory results, a diagnosis of homocystinuria was made. Homocystinuria is an inherited disorder that affects the metabolism of the amino acid methionine. Although homocystinuria is usually associated with ischemic strokes, the sudden onset of stroke as the initial clinical presentation of homocystinuria is very rare in early childhood. Based on this case, however, metabolic screening for hyperhomocystinemia is recommended in any child presenting with a stroke.

Inborn errors of metabolism for the diagnostic radiologist

Inherited metabolic disorders are becoming more important with the increasing availability of diagnostic methods and therapies for these conditions. The radiologist has become an important link in making the diagnosis or collaborating with the specialist centre to diagnose these disorders and monitor effects of therapy. The modes of presentation, disease-specific groups, classic radiological features and investigations are explored in this article to try and give the general radiologist some crucial background knowledge. The following presentations are covered: acute intoxication, hypoglycaemia, developmental delay and storage features. Specific groups of disorders covered are the abnormalities of intermediary metabolism, disorders of fatty acid oxidation and ketogenesis, mitochondrial disorders, lysosomal storage disorders, and, briefly, other groups such as peroxisomal disorders, disorders of glycosylation, and creatine synthesis disorders. New advances and the demands for monitoring are also briefly explored.

Cerebrospinal fluid analysis in the diagnosis and treatment of arterial ischemic stroke

With the advent of magnetic resonance imaging as a rapid and accurate way to diagnose arterial ischemic stroke, cerebrospinal fluid assessment is rarely performed, unless infectious or inflammatory processes are obvious. Recent advances in the understanding of the pathophysiology of childhood stroke have implicated a growing list of discrete or occult infectious and inflammatory conditions which may involve intracranial arteries and neighboring structures. Cerebrospinal-fluid assessment may allow the detection of markers identifying processes (including infectious, inflammatory, metabolic, and traumatic) potentially involved in cerebral vasculopathy and stroke. The analysis of cerebrospinal fluid in arterial ischemic strokes, including apparently idiopathic strokes, may yield essential information on pathophysiology, allowing for optimal therapeutic decisions and prognostic considerations.

Single gene disorders causing ischaemic stroke

Stroke is the third most common cause of death and the leading cause of long-term neurological disability in the world. Conventional vascular risk factors for stroke contribute approximately to only forty to fifty percent of stroke risk. Genetic factors may therefore contribute to a significant proportion of stroke and may be polygenic, monogenic or multi-factorial. Monogenic (single gene) disorders may potentially account for approximately one percent of all ischaemic stroke. Monogenic stroke disorders include conditions such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) and hereditary endotheliopathy, retinopathy, nephropathy and stroke (HERNS). In addition, other monogenic conditions such as sickle cell and Fabry disease also lead to stroke. These monogenic disorders cause either small vessel or large vessel stroke (or a combination of both) and serve as useful models for understanding and studying conventional stroke and cerebrovascular disease and its accompaniments such as vascular dementia.

Defining the Effect of Cervical Manipulation on Vertebral Artery Integrity: Establishment of an Animal Model

BACKGROUND

Cervical spine manipulation is most often performed to affect relief of musculoskeletal complaints of the head and neck. Performed typically without complication, this modality is thought to be a potential cause of cerebrovascular injury, although a cause-effect relation has yet to be established. To explore this relation, an experimental platform is needed that is accessible and biologically responsive.

OBJECTIVE

To establish an animal model capable of accommodating (1) direct study of its vertebral arteries and (2) creation of controlled interventions simulating arterial injury.

STUDY DESIGN

Descriptive.

METHODS

Under fluoroscopic guidance, an ultrasonic catheter was inserted into the left vertebral artery of 3 anesthetized dogs. The ultrasonic probe was then drawn proximally through the artery at a specific rate, and cross-sectional images of the vessel were collected. These images were then reconstructed to provide a variety of 2- and 3-dimensional representations of the vessel. This procedure was repeated after the overinflation and/or displacement of an angiographic balloon within the vertebral artery itself.

RESULTS

The resulting ultrasonic images were able to delineate the structural layers that constitute the vertebral artery. Analysis of 2- and 3-dimensional reconstructions before and after angiographic intervention revealed the creation of discrete vascular injuries (aneurysm or dissection).

CONCLUSIONS

For the first time, an animal model has been established that permits direct interrogation of the internal structures of the vertebral artery. This model can also be manipulated to create "preexisting" vascular injuries that are thought to be possible prerequisites for cerebrovascular injury associated with manipulation. As a result, an experimental platform has been established that is capable of providing investigators of all backgrounds with the ability to quantify biologic and mechanical outcomes of cervical manipulation.

Risk factors for arterial ischemic stroke in children

Since early recurrence occurs in at least 10% of patients presenting with their first stroke in childhood in the reported series, the search for modifiable risk factors should be a priority. Risk factors for stroke in adults include hypertension, diabetes, and smoking, as well as cardiac disease and sickle cell anemia; asymptomatic cerebrovascular disease and transient ischemic events may predict stroke in this age group. The investigation of a child with a stroke has traditionally focused on finding a single cause rather than looking for risk factors to which the patient may be exposed life long. Approximately half of children presenting with stroke have a known predisposing condition, but some have unexpected pathologies such as primary cerebrovascular disease associated with congenital heart anomalies, or may have modifiable risk factors such as hypertension associated with sickle cell disease. The literature on children presenting with initially unexplained (cryptogenic) stroke suggests that there is a daunting list of possible causes, but since the series have mainly been small, it has been difficult to evaluate the relative importance of the reported associations. This paper reviews the literature on congenital, genetic, and acquired risk factors for stroke in childhood, and includes data from the large series of patients seen at Great Ormond Street Hospital over the past 10 years. The majority have arteriographic abnormalities and there is little evidence for asymptomatic cardiac disease. Genetic predisposition, trauma, infection, and nutritional deficiencies appear to be important, although case-control studies will be required to prove causation. Appropriate screening for modifiable risk factors may lead to prevention of recurrence in some patients. In the long term, an understanding of the multiple etiologies of childhood cerebrovascular disease and ischemic stroke may lead to primary prevention in this age group, and perhaps in adults.

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.