Charcot-Marie-Tooth (CMT) disease 1A with superimposed inflammatory polyneuropathy in children

Charcot-Marie-Tooth (CMT) disease is genetically heterogeneous and subdivided into demyelinating (CMT 1) and axonal (CMT 2) types based on neurophysiology findings. CMT1A, the commonest form associated with duplication of the PMP22 segment on chromosome 17p, often arises in childhood but is generally a slowly progressive disease. We report 2 children presenting with clinical features of an acute inflammatory demyelinating polyneuropathy (AIDP) who were subsequently diagnosed with underlying CMT1A. Both children had neurophysiology and histopathology features consistent with CMT1. Immunoglobulin treatment was initiated considering the evidence of superimposed inflammation and appeared to modify disease progression. Our findings indicate that CMT1A predisposes to a superimposed inflammatory neuropathy. Recognition of this association is difficult, particularly in children without clear family history, but of great importance as immunomodulatory treatment may improve outcome. In addition, we postulate that an underlying genetic polyneuropathy should be suspected if the recovery from AIDP is slower than expected, or incomplete.

Interfamilial phenotypic heterogeneity in SMARD1

Spinal muscular atrophy with respiratory distress (SMARD1: mu-binding protein 2 gene mutation) is characterised by low birth weight, progressive distal limb weakness, diaphragmatic paralysis and subsequent respiratory failure manifesting before 13 months of age. Our case report illustrates marked phenotype variability in two siblings with an identical genetic mutation of SMARD1, one of whom died of fulminant respiratory failure aged 6 months, whereas the other shows limb weakness but, only mild sleep hypoventilation aged 12 years. This suggests other compensatory mechanisms may play a role in modifying SMARD1; broadening our perception of phenotype. Therefore, SMARD1 phenotype should be considered in cases of atypical spinal muscular atrophy even in the absence of overt diaphragmatic weakness.

Surgery for scoliosis in Duchenne muscular dystrophy

BACKGROUND

Scoliosis in people with Duchenne muscular dystrophy is usually progressive and treated with surgery. However, it is unclear whether the existing evidence is sufficiently scientifically rigorous to support a recommendation for spinal surgery for most people with Duchenne muscular dystrophy and scoliosis.

OBJECTIVES

The objectives of this systematic review were to determine the effectiveness and safety of spinal surgery in Duchenne muscular dystrophy patients with scoliosis. We intended to test whether spinal surgery is effective in increasing life expectancy, improving respiratory function, improving quality of life and overall functioning; and whether spinal surgery is associated with severe adverse effects.

SEARCH STRATEGY

We searched the specialized registers of the Cochrane Neuromuscular Disease Group and Cochrane Back Group, the Cochrane Central Register of Controlled Trials (January 2006), MEDLINE (January 1966 to January 2006), EMBASE (January 1980 to January 2006), Dissertation Abstracts International (1861 to Jan 2006), CINAHL (January 1982 to January 2006), and the National Institute of Health Clinical Trials Database (January 2006). No language restrictions were imposed.

SELECTION CRITERIA

Controlled clinical trials using random or quasi-random allocation of treatment evaluating all forms of spinal surgery for scoliosis in patients with Duchenne muscular dystrophy were to be included in the review. The control interventions would have been no treatment, non-operative treatment, or a different form of spinal surgery.

DATA COLLECTION AND ANALYSIS

Two authors examined the search results and evaluated the study characteristics against inclusion criteria to decide which ones would be included in the review.

MAIN RESULTS

A total of 402 studies were identified from electronic searching. Thirty-six studies were relevant but none met the inclusion criteria for the review, because they were not clinical trials but prospective or retrospective reviews of case series.

AUTHORS' CONCLUSIONS

Since there were no randomized controlled clinical trials available to evaluate the effectiveness of scoliosis surgery in people with Duchenne muscular dystrophy, no evidence-based recommendation can be made for clinical practice. Patients should be informed about the uncertainty of benefits and potential risks of surgery for scoliosis. Randomized controlled trials are needed to investigate the effectiveness of scoliosis surgery, in terms of patients' quality of life, functional status, respiratory function and life expectancy.

A proposed classification for subtypes of arterial ischaemic stroke in children

The aim of this study was to propose a classification system for childhood arterial ischaemic stroke (AIS). Subtypes from the Trial of Org 10172 in Acute Stroke Therapy (TOAST) classification, previously shown to be applicable to children, were retained in the proposed Paediatric Stroke Classification (PSC). Additional important paediatric AIS aetiologies were identified from a literature review. Preliminary validation was performed by three raters who categorized clinical vignettes from 135 patients (66 male; median age 6.3 y, range 0.1 to 16 y). Eight aetiological subtypes were identified and defined, as follows: (1) sickle cell disease; (2) cardioembolic; (3) moyamoya syndrome; (4) cervical arterial dissection; (5) steno-occlusive cerebral arteriopathy; (6) other determined aetiology; (7) multiple probable/possible aetiologies; and (8) undetermined aetiology. There was very good agreement between the raters about categorization of the vignettes. Causes of disagreement were identified and final categories and definitions were modified accordingly. We conclude that the PSC enables the categorization of children with AIS into aetiological subtypes relevant to this age group. This will be useful in multicentre studies of natural history and treatment but will require further independent validation.

Arterial dissection complicating tonsillectomy

Tonsillectomy is a frequently performed surgical procedure. Surgical complications can be serious. We report the case of a 7-year-old female who experienced an arterial ischaemic cerebral infarction following elective adenotonsillectomy.

Ischaemic stroke subtypes in children and adults

Ischaemic stroke subtypes in children and adults were compared to determine the similarity in aetiologies. Thirty-six children (22 females, 14 males; median age 5 years 7 months, range 6 weeks to 15 years 10 months) and 50 adults (35 males, 15 females; median age 44 years, range 17 years 2 months to 49 years 11 months) who had presented with ischaemic stroke between 1995 and 2000, were categorized using a modified version of the Trial of Org 10172 in Acute Stroke Therapy (TOAST) classification. Proportions of patients in the subtypes of the TOAST classification system were significantly different in the two groups (chi2 test, p<0.01). The first three subtypes (large artery atherosclerosis, cardioembolic, and small vessel disease) accounted for the majority of adult strokes (27 of 50). In contrast, only three of 36 children were accounted for within these three subtypes. The majority of children (29 of 36) were classified within the 'other determined aetiology' subtype. Aetiology was undetermined in 12 of 50 adults compared with three of 36 children. Causes of ischaemic stroke in children and adults are distinct. A classification system for ischaemic stroke in children would be useful for collaborative studies.

Neurocysticercosis masquerading as a cerebral infarct

The differential diagnosis of acute focal neurologic deficit in childhood is diverse. We report the case of a child presenting with an acute hemiparesis persisting for longer than 24 hours following a focal seizure. The clinical history, examination findings, and results of cranial magnetic resonance imaging (MRI) were initially interpreted as consistent with an arterial ischemic cerebral infarction. Follow-up cranial MRI performed 9 months later revealed changes indicative of neurocysticercosis. Review of original neuroimaging resulted in a revision of the diagnosis to neurocysticercosis. The clinical history, together with neuroimaging findings, is highly compatible with a diagnosis of neurocysticercosis but unusual because it occurred in a child resident in a nonendemic area who had never traveled to an endemic area and whose diet excluded pork. The case reported raises two important issues. The first is the need to carefully consider the differential diagnosis of acute hemiparesis, including unusual causes. Second, it raises awareness of the potential for neurocysticercosis to occur in low-risk patients in nonendemic areas.

Fat oxidation defect presenting with overwhelming ketonuria

Ketonuria accompanying hypoglycaemia is conventionally thought to exclude fat oxidation defects. We describe a 2 year old girl with hypoglycaemic encephalopathy in whom a diagnosis of very long chain acyl CoA dehydrogenase deficiency was suggested on the basis of acylcarnitine analysis despite massive ketonuria.

Idiopathic intracranial hypertension: is papilloedema inevitable?

Headaches and papilloedema are key features of idiopathic (benign) intracranial hypertension (IIH). We describe three children in whom IIH was diagnosed in the absence of papilloedema. Recognition of atypical cases of IIH is important because pressure lowering treatment may be effective.

Investigation of daytime wetting: when is spinal cord imaging indicated?

BACKGROUND

Most children with daytime wetting have detrusor instability. A minority have neuropathic vesicourethral dysfunction. The commonest cause is spina bifida, which may be closed. Clinical features suggestive of closed spina bifida include cutaneous, neuro-orthopaedic or lumbosacral spine x ray abnormalities, impaired bladder sensation, and incomplete bladder emptying. MRI is the ideal method for detecting spinal cord abnormality. It has been suggested that MRI spine is an unnecessary investigation in children with daytime wetting in the absence of cutaneous, neuro-orthopaedic, or lumbosacral spine x ray abnormalities.

AIM

To clarify indications for magnetic resonance imaging (MRI) of the spine in children with voiding dysfunction.

METHODS

Retrospective study of children with voiding dysfunction referred from the Guy's Hospital neurourology clinic for MRI spine between April 1998 and April 2000. Clinical notes and results of investigations, including urodynamic studies and MRI spine were reviewed.

RESULTS

There were 48 children (median age 9.1 years). Closed spina bifida was detected in five, of whom four had neuropathic vesicourethral dysfunction confirmed by urodynamic studies. Impaired bladder sensation and incomplete bladder emptying were more frequent in these children than in those with normal MRI spine. One child with spinal cord abnormality had no cutaneous, neuro-orthopaedic, or lumbosacral spine x ray abnormalities.

CONCLUSION

Spinal cord imaging should be considered in children with daytime wetting when this is associated with impaired bladder sensation or poor bladder emptying, even in the absence of neuro-orthopaedic, cutaneous, or lumbosacral spine x ray abnormalities.

Hydrocarbon humps in the marine environment: synthesis, toxicity, and aqueous solubility of monoaromatic compounds

A recent study has shown that some monoaromatic hydrocarbon constituents of the so-called unresolved complex mixtures (UCMs) or gas chromatographic humps, which are widespread in the marine environment, are toxic to the mussel Mytilus edulis. Here we describe the synthesis and toxicological assessment of 6-cyclohexyltetralin, 7-cyclohexyl-1-methyltetralin, and 7-cyclohexyl-1-n-propyltetralin, which contain structural features consistent with some monoaromatic UCM hydrocarbons. The compounds were all toxic to M. edulis when measured in the assay used previously to determine the toxicity of a monoaromatic UCM. The aqueous solubilities of the hydrocarbons in fresh and seawater at different temperatures were determined and found to range from about 10 to 110 microg/L (10-60 microg/L in seawater at 15 degrees C). Further studies of the aromatic UCM composition of a wide range of oils and oil residues are required to determine whether such alkylated compounds as 7-cyclohexyl-1-methyltetralin and 7-cyclohexyl-1-n-propyltetralin or their analogues are widespread in oils. If these aromatic compounds prove to be important in UCMs, toxicity experiments should be conducted with other biological end points and monitoring studies of pollutant hydrocarbons should probably include measurement of aromatic UCM hydrocarbons.

Aromatic hydrocarbon "humps" in the marine environment: unrecognized toxins?

Gas chromatographic analysis of the hydrocarbons of environmental samples often reveals that unresolved complex mixtures (UCMs) or gas chromatographic "humps" of aliphatic and aromatic hydrocarbons are most abundant--yet little consideration seems to have been given to the possible toxicological impacts of hydrocarbon "humps". Here we show, using a well-accepted bioassay, that monoaromatic components of a UCM of hydrocarbons from a crude oil elicit a sublethal toxic response in a typical marine pollution indicator organism (the mussel, Mytilus edulis). Furthermore, coastal U.K. mussels shown previously to have unexplained impaired health contained high concentrations of UCMs, including monoaromatic UCMs. These findings may have important implications for our understanding of the toxicological sublethal effects of oil residues in the environment. Given the relatively resistant nature of UCM hydrocarbons, the effects of both acute oil spills and more chronic discharges may need further consideration.