Painful diabetic neuropathy: diagnosis and management

The prevalence of painful diabetic peripheral neuropathy (PDN) is about 20% in patients with type 2 diabetes and 5% in those with type 1. Patients should be systematically questioned concerning suggestive symptoms, as they are not usually volunteers. As PDN is due to small-fibre injury, the 10 g monofilament pressure test as well as the standard electrophysiological procedures may be normal. Diagnosis is based on clinical findings: type of pain (burning discomfort, electric shock-like sensation, aching coldness in the lower limbs); time of occurrence (mostly at rest and at night); and abnormal sensations (such as tingling or numbness). The DN4 questionnaire is an easy-to-use validated diagnostic tool. Three classes of drugs are of equal value in treating PDN: tricyclic antidepressants; anticonvulsants; and selective serotonin-reuptake inhibitors. These compounds may be prescribed as first-line therapy following pain assessment using a visual analogue scale. If the initial drug at its maximum tolerated dose does not lead to a decrease in pain of at least 30%, another drug class should be prescribed; if the pain is decreased by 30% but remains greater than 3/10, a drug from a different class may be given in association.     

Multicenter randomized clinical trial of retinal photocoagulation for preproliferative diabetic retinopathy

Purpose  

To evaluate the effectiveness of selective photocoagulation (S-PC) for nonperfusion areas (NPA) in preproliferative diabetic retinopathy (PPDR).     

Growth hormone secretory pattern in non-obese children and adolescents with Prader-Willi syndrome

The aetiology of impaired growth hormone (GH) secretion in Prader-Willi syndrome (PWS) remains controversial due to the common occurrence of obesity. To further clarify whether suboptimal GH secretion in PWS is an artefact of excess weight, we evaluated both GH immunological activity and GH bioactivity after arginine administration in 23 non-obese PWS patients [seven females, aged 6.9 +/- 0.9 years, body mass index (BMI) SDS 0.63 +/- 0.26], in comparison with a control group of 32 healthy subjects, matched for age, gender and BMI (10 females, aged 7.9 +/- 0.3 years, BMI SDS 0.21 +/- 0.20). Serum GH concentration was measured with a time-resolved immunofluorometric assay (IFMA), while GH bioactivity was evaluated by the Nb2 cell bioassay. Serum IGF-I concentrations were measured by double-antibody RIA. GH mean peak after pharmacological stimulation was significantly lower in PWS individuals compared with controls when measured either by IFMA (6.05 +/- 1.23 microg/L vs. 23.7 +/- 1.06 microg/L, p < 0.0001) or by Nb2 (6.87 +/- 0.55 microg/L vs. 12.88 +/- 0.19 microg/L, p < 0.0001). Analysis of integrated GH secretion (AUC) confirmed that the PWS group differed significantly from the control subjects (387.9 +/- 76.1 microg/L/h vs. 1498.1 +/- 56.2 microg/L/h, p < 0.0001); the same result was obtained when the GH rise after arginine administration was expressed as nAUC (278.2 +/- 53.3 microg/L/h vs. 1443.6 +/- 52.5 microg/L/h, p < 0.0001). PWS patients had an IGF-I SDS significantly lower than those found in control subjects (p < 0.0001). Subnormal IGF-I values were present in 19 PWS individuals (82.6%) and two healthy controls (6.2%). These findings are in agreement with the hypothesis that a complex derangement of hypothalamus-pituitary axis occurs in PWS.     

Maturity-Onset Diabetes of the Young in Children With Incidental Hyperglycemia:: A multicenter Italian study of 172 families

OBJECTIVE

To investigate the prevalence of maturity-onset diabetes of the young (MODY) in Italian children with incidental hyperglycemia.

RESEARCH DESIGN AND METHODS

Among 748 subjects age 1–18 years with incidental hyperglycemia, minimal diagnostic criteria for MODY were met by 172 families. Mutational analyses of the glucokinase (GCK) and hepatocyte nuclear factor 1α (HNF1Α) genes were performed.

RESULTS

We identified 85 GCK gene mutations in 109 probands and 10 HNF1Α mutations in 12 probands. In GCK patients, the median neonatal weight and age at the first evaluation were lower than those found in patients with HNF1A mutations. Median fasting plasma glucose and impaired fasting glucose/impaired glucose tolerance frequency after oral glucose tolerance testing were higher in GCK patients, who also showed a lower frequency of diabetes than HNF1A patients.

CONCLUSIONS

GCK mutations are the prevailing cause of MODY (63.4%) when the index case is recruited in Italian children with incidental hyperglycemia.Between 1992–1999, the Italian Society of Pediatric Endocrinology and Diabetology (ISPED) Study Group on childhood pre-diabetes recruited 748 individuals with incidental hyperglycemia to be screened for markers of type 1 diabetes (1,2). Among autoantibody-negative subjects, a significant number (∼23%) met the criteria for clinical diagnosis of maturity-onset diabetes of the young (MODY), i.e., two or three consecutive generations with hyperglycemia diagnosed before age 25 years (3,4). Alterations in at least six different genes cause MODY (3), with mutations of the glucokinase (GCK) and hepatocyte nuclear factor 1α (HNF1Α) genes accounting for up to 85% of MODY in Europe. Defects of other MODY genes are quite rare (3). The aim of this study was to screen for GCK and HNF1Α genes in 172 Italian children with incidental hyperglycemia and clinical diagnosis of MODY.     

Death during GH therapy in children with Prader-Willi syndrome: description of two new cases

A few cases of death worldwide during GH treatment in pediatric patients with Prader-Willi syndrome (PWS) have been recently described. The evaluation of further cases is needed to better identify possible causal mechanism(s), as well as to suggest some additional guidelines for prevention. We report the death of 2 additional children with genetically confirmed PWS in the first months of GH therapy. Case 1: This 3.9-yr-old girl was born at 39 weeks gestation. Low GH response to two stimulation tests was observed. GH administration was started at the age of 3.5 yr (0.33 mg/kg per week), when the patient was at 130% of her ideal body weight (ibw). Hypertrophy of adenoids was previously demonstrated. Snoring and sleep apnea were present before GH treatment, and did not increase during therapy. Four months later she died at home suddenly in the morning. Case 2: This patient was a 6.3-yr-old boy. He was born at term after an uneventful pregnancy. At the age of 6 yr, his weight was at 144% of his ibw. He showed reduced GH secretion during provocation tests, and GH therapy was started (0.20 mg/kg per week). The previously reported nocturnal respiratory impairment had worsened after beginning GH administration. Tonsils and adenoids hypertrophy were noted. At the age of 6.3 yr he died at home in the morning following an acute crisis of apnea. These additional cases seem to confirm that some children with PWS may be at risk of sudden death at the beginning of GH therapy.     

Neonatal hypotonia: don't forget the Prader-Willi syndrome

During the neonatal period the diagnosis of the Prader-Willi syndrome (PWS) is difficult because the syndrome is expressed mainly by severe hypotonia at this age and the typical clinical features of later life are not yet present. AIM: To identify all the PWS clinical markers in severe hypotonic newborns, which could facilitate an early diagnosis of the syndrome. METHODS: Twenty-one PWS newborns (14 males and 7 females) with severe hypotonia at birth were evaluated. Paediatricians skilled in syndromology carried out a careful clinical examination. Fluorescent in situ hybridization (FISH) analysis and/or a methylation test was used to confirm the PWS clinical diagnosis. RESULTS: The clinical diagnosis of PWS was reached at a mean age of 7.4 mo with genetic confirmation at 11 mo of life. In 12 newborns at least 3 craniofacial features were present (57%), suggesting the diagnosis of PWS. Two craniofacial dysmorphic characteristics were described in 6 newborns and only 1 in 3 cases. Cryptorchidism was monolateral in 6 and bilateral in 7 patients; in one newborn both testes were in scrotum. A micropenis was described in one patient and hypoplasia of the labia minora was reported in two females. CONCLUSIONS: Diagnosis by means of dysmorphologic evaluation is difficult in the neonatal period. The presence of severe hypotonia should always induce neonatologists to perform specific genetic tests in order to obtain an early diagnosis of PWS.