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D M Isherwood

Publications and source records attributed to D M Isherwood.

At least 19 recordsLinked to original sources
PubMed2007

Biochemical severity of thyroid ectopia in congenital hypothyroidism demonstrates sexual dimorphism.

BACKGROUND: A recent study suggested that sexual dimorphism affects initial thyroid function in congenital hypothyroidism (CH) but differs according to aetiology of CH. AIMS: To determine if sexual dimorphism was associated with biochemical severity of CH and its aetiology in our large British population. METHODS: We examined retrospectively the initial thyroid function tests of 140 infants diagnosed with CH from screening. All infants underwent Tc-pertechnetate radionuclide scans at diagnosis to establish the aetiology of CH prior to commencement of treatment. Patients were classified into athyreosis, ectopia and presumed dyshormonogenesis on the basis of thyroid scans. A comparison of males and females were made within the three aetiological groups for gestational age, birth weight, initial dose of levothyroxine (LT4), screening TSH, confirmatory plasma thyroxine (T4), confirmatory plasma TSH and age of TSH suppression. RESULTS: There was no significant difference between sexes for gestation, birth weight and initial treatment dose in all aetiological subgroups. In thyroid ectopia, screening TSH and confirmatory plasma TSH were significantly higher in females compared with males (P < 0.01), while confirmatory plasma T4 were significantly lower in females (P < 0.05). No difference was detected between males and females in athyreosis and dyshormonogenesis subgroups for screening TSH, confirmatory plasma TSH and total T4. CONCLUSION: Sexual dimorphism influenced the biochemical severity of thyroid ectopia in congenital hypothyroidism in our British population. However, this effect was not apparent in patients with athyreosis or dyshormonogenesis. Further advances in the molecular genetics of CH are essential to evaluate this phenomenon further.

Choristoma↗
PubMed2006

Guanidinoacetate methyltransferase deficiency masquerading as a mitochondrial encephalopathy.

Guanidinoacetate methyltransferase (GAMT) deficiency is a rare disorder of creatine synthesis. We report a patient who presented at 10 months of age with hypotonia and global developmental delay. Subsequently, she developed seizures and choreoathetosis. Magnetic resonance imaging showed high signal bilaterally in the globus pallidus on T2-weighted images. Mitochondrial respiratory chain studies revealed low complex I activity (in muscle 0.052 nmol NADH oxidized per min per unit citrate synthase, controls 0.166 +/- 0.047; in fibroblasts 0.080 nmol NADH oxidized per min per unit citrate synthase, controls 0.197 +/- 0.034). The true diagnosis was suspected at 21 months of age because of persistent low plasma and urine creatinine concentrations. GAMT activity was undetectable in fibroblasts and compound heterozygous mutations were found in the GAMT gene (c.327G>A and c.522G>A). The patient was treated with creatine, dietary arginine restriction and ornithine supplements. Her movement disorder and seizures resolved but she still has severe cognitive impairment and no expressive language. The occurrence of secondary respiratory chain abnormalities in GAMT deficiency may lead to misdiagnosis, particularly as the clinical and radiological features resemble those seen in mitochondrial encephalopathies. It is important to establish the correct diagnosis because specific treatment is available.

Brain↗
PubMed2004

Multivariate analysis on factors affecting suppression of thyroid-stimulating hormone in treated congenital hypothyroidism.

AIMS: To determine the factors which influence the suppression of thyroid-stimulating hormone (TSH) in infants with congenital hypothyroidism (CH) following treatment. METHODS: We examined retrospectively the patterns of thyroid function tests from diagnosis to 3 years of age in 140 infants diagnosed with CH from screening. Patients were classified into 3 groups: athyreosis, ectopia and presumed dyshormonogenesis on the basis of thyroid scans. Adequate TSH suppression was defined as plasma TSH concentration <6 mU/l. The factors affecting the suppression of TSH at 6 months and 1 year of age which were evaluated were: initial confirmatory plasma TSH, initial plasma thyroxine (T4), mean age of starting treatment with L-T4, dose of L-T4 at diagnosis, 6 weeks, 3 months and 6 months, and aetiology of the congenital hypothyroidism. Variables were then entered in a stepwise logistic regression model for TSH suppression at 6 months and 1 year of age. RESULTS: All infants had radionuclide scans prior to treatment: athyreosis (n = 39), ectopia (n = 78) and dyshormonogenesis (n = 23). 58% of patients had persistently raised TSH at 6 months of age while 31% of patients had a persistently raised TSH at 1 year of age. There was a significant delay in the normalisation of plasma TSH in athyreosis and ectopia groups compared with dyshormonogenesis. Multiple regression analysis for TSH suppression at 6 months of age found plasma T4 levels and aetiology of CH as independent factors affecting the timing of TSH suppression. Aetiology of CH was the only independent factor affecting TSH suppression at 1 year of age. CONCLUSION: At 6 months of age, plasma T4 levels at 6 weeks and 3 months, and aetiology of CH were independent factors affecting timing of TSH suppression. However, by 1 year of age, the aetiology of CH was the only independent factor affecting suppression of TSH.

Child, Preschool↗
PubMed1996

Homocystinuria.

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Homocystinuria↗
PubMed1991

Autoimmune Addison's disease and thyrotoxic thyroiditis presenting as encephalopathy in twins.

An 11 year old boy who presented with neuropsychiatric symptoms including delirium and pronounced agitation was found to have simultaneous onset of autoimmune adrenocortical insufficiency and hyperthyroidism. His identical twin also had hyperthyroidism and six months later developed symptoms of adrenocortical insufficiency. In children presenting with neuropsychiatric symptoms, adrenal (or pituitary) and other endocrine disorders should be considered.

Addison Disease↗
PubMed1982

A simplified system of human milk banking.

A simplified system of human milk banking, from milk supplied from home or hospital, has been evaluated for use in a neonatal intensive care unit. Twenty milk samples were obtained at a single expression using a standard hand pump and divided into three parts. Analyses were performed on the raw milk and on samples stored at -20 degrees C for 1 week and 1 month. No pathogens were isolated from any samples and the counts of Staphylococcus albus in the raw milk remained unchanged after storage. 19% of the cells in the original milk survived freezing and remained viable. There was a loss of bacteriostatic activity after storage for one month but significantly less than that caused by pasteurization. No change in levels of IgA, IgM, IgF, lactoferrin, lysozyme, C3 and C4 was apparent and concentrations of amino acids and fatty acids also remained unchanged after storage. We conclude that milk can be safely and conveniently stored by this method without loss or damage to the components of raw breast milk important for preterm and sick infants.

Amino Acids↗