James P. Keating

Neonatal necrotizing enterocolitis. Therapeutic decisions based upon clinical staging.

A method of clinical staging for infants with necrotizing enterocolitis (NEC) is proposed. On the basis of assigned stage at the time of diagnosis, 48 infants were treated with graded intervention. For Stage I infants, vigorous diagnostic and supportive measures are appropriate. Stage II infants are treated medically, including parenteral and gavage aminoglycoside antibiotic, and Stage III patients require operation. All Stage I patients survived, and 32 of 38 Stage II and III patients (85%) survived the acute episode of NEC. Bacteriologic evaluation of the gastrointestinal microflora in these neonates has revealed a wide range of enteric organisms including anaerobes. Enteric organisms were cultured from the blood of four infants dying of NEC. Sequential cultures of enteric organisms reveal an alteration of flora during gavage antibiotic therapy. These studies support the use of combination antimicrobial therapy in the treatment of infants with NEC.

Glycogen Storage Disease in Adults

Table 1 The glycogen storage diseases (GSD) include more than ten separate genetic defects that impair glycogen breakdown, primarily in liver or muscle or both. Even the types most frequently encountered (GSD-Ia and GSD-III) are uncommon, each with an incidence of approximately 1 in 100 000 births. Thus, no single institution has followed and reported on a large series of patients. The importance of several major complications was recognized only recently because only single cases were initially reported. Our study represents the largest number of adults with GSD-Ia and GSD-Ib to be included in one investigation and is the first to focus on clinical and social outcomes. Although two groups of investigators recently described the clinical course of patients with GSD in Europe and Israel, most of the patients studied were children [1, 2]. Relatively little information is available about adults with these diseases. We collected information on adults with GSD-Ia, GSD-Ib, and GSD-III in the United States and Canada in order to identify long-term complications that may be amenable to prevention and to determine the effect of the disease on education, employment, and family life. Table 1. SI Units Glycogen Storage Disease Types Ia, Ib, and III Glycogen storage disease type Ia results from deficient glucose-6-phosphatase activity in liver, kidney, and intestine [3]. Glucose-6-phosphatase is a single 35-kd protein [4]. When glucose-6-phosphatase activity is deficient, the liver is unable to hydrolyze glucose from glucose-6-phosphate that has been derived either from the metabolism of stored glycogen or from gluconeogenesis. Patients must depend on dietary carbohydrate to maintain euglycemia; during a fast of more than a few hours, the serum glucose concentration may decrease profoundly, and seizures are common in children. Mental retardation is uncommon, however, because the brain is protected by its ability to metabolize lactate that is present at high concentrations in the serum. Chronic hypoglycemia causes a sustained increase of counter-regulatory hormones, such as cortisol. In childhood, GSD-Ia typically results in poor growth and delayed puberty. Hyperuricemia occurs probably because ATP synthesis from ADP is driven by deamination of the AMP product to inosine that is subsequently metabolized to uric acid. Renal excretion of uric acid may also be decreased because lactate competes for the renal anion transporter. Fatty liver and hyperlipidemia result from the large influx of adipose-derived fatty acids into the liver in response to low insulin and high glucagon and cortisol concentrations. Anemia that is refractory to iron supplementation is believed to occur because of chronic disease. In untreated adults with GSD-Ia, the blood glucose decreases only to about 2.8 mmol/L (50 mg/dL) after an overnight fast. Symptomatic hypoglycemia is uncommon in untreated adults, but increases of counter-regulatory hormones probably persist. Adults with GSD-Ia have a high incidence of hepatic adenomas and focal segmental glomerulosclerosis [3, 5, 6]. The continuing abnormalities in counter-regulatory hormones, together with the hyperuricemia and hyperlipidemia, may be responsible for many of the complications observed in adult patients. Glycogen storage disease type Ib results from a deficiency of the glucose-6-phosphate translocase that transports glucose-6-phosphate into the lumen of the endoplasmic reticulum where it is hydrolyzed by glucose-6-phosphatase [3]. The translocase has not been purified. Without the translocase, glucose-6-phosphate cannot reach the hydrolytic enzyme; thus, patients with GSD-Ib are also unable to maintain euglycemia. The resulting metabolic consequences are identical in both forms of GSD-I. Because patients with GSD-Ib also have neutropenia and recurrent bacterial infections [3, 7], it seems likely that the glucose-6-phosphate translocase plays a role in normal neutrophil function. In GSD-III, glycogen debranching enzyme is deficient [3]. This enzyme is a 165-kd protein that contains two catalytic sites that are required for activity. The enzyme has been cloned and sequenced [8]. Normally, successive glucose residues are released from glycogen by glycogen phosphorylase until the glycogen chains are within four glucose residues of a branch point. The first catalytic activity of the debranching enzyme (oligo-1,4,-1,4-glucantransferase) transfers three of the remaining glucose residues to the terminus of another glucose chain. The second catalytic activity (amylo-1,6-glucosidase) then hydrolyzes the branch-point glucose residue. Three molecular subgroups of GSD-III have been well defined [9]; each is associated with enzyme deficiency in the liver and with childhood hypoglycemia. In adults with GSD-III, hypoglycemia is uncommon. As in GSD-I, poor growth may be prominent, but the growth rate increases before puberty, and adult height is normal [10]. Additionally, increases in transaminase levels provide evidence of hepatocellular damage, and liver biopsies show periportal fibrosis [10], perhaps related to the abnormal short-branched glycogen structure. In patients with subtype GSD-IIIb, enzyme activity and immunoreactive material are absent in liver but are present in muscle; these patients do not have a myopathy. Patients with GSD-IIIa (78% of cases) lack enzyme activity and lack immunoreactive material in liver and muscle. Patients with GSD-IIId (7% of cases) lack only the transferase activity but have normal immunoreactive material in liver and muscle. In patients with GSD-IIIa and IIId, muscle weakness may occur either in childhood or after the third decade. Cardiomyopathy is apparent only after age 30 years [9]. Treatment of Glycogen Storage Disease For only the past 10 to 15 years, children with GSD-Ia and GSD-Ib were treated with either intermittent uncooked cornstarch or a nocturnal glucose infusion given by intragastric tube. When euglycemia is maintained in this manner, growth and pubertal development are normal, and it is hoped that the late complications of GSD-I will be prevented. A high-protein diet was recommended for patients with GSD-III. Diet supplementation can increase the growth rate in children with GSD-III [11], but beneficial results on the myopathy have been less well documented. In this retrospective study of adults with GSD types Ia, Ib, and III, we found, in addition to complications frequently recognized, a high incidence of osteopenia and fractures and of nephrocalcinosis, kidney stones, and pyelonephritis. We describe the long-term outlook for adult patients with GSD who have not had optimal lifelong dietary glucose therapy. Methods Information on patients 18 years of age or older was obtained by contacting specialists in pediatric metabolism, endocrinology, gastroenterology, and genetics throughout the United States and Canada and by advertising through the Association for Glycogen Storage Diseases and The New England Journal of Medicine. No registries of patients with GSD are available. Information was included on living adult patients with GSD and patients who had died since 1967. Diagnosis of GSD had been confirmed by enzyme assay of each patient or of an affected sibling. Fifty-six physicians were individually contacted. Nineteen stated that they were not treating any adult patients with GSD. Thirteen physicians in private practice or at 1 of 12 medical centers filled out a detailed questionnaire or sent copies of clinic and hospital records that were reviewed by two of us. To obtain an estimate of how many patients might be missed by this survey, we reviewed records from a reference laboratory (Washington University) of 21 patients with GSD-Ia and of 21 patients with GSD-III who were diagnosed between 1955 and 1972. If still alive, these patients would now range in age from 18 to 64 years. Our study includes only 5 of these patients with GSD-I and 1 with GSD-III. Thus, this report incompletely represents North American patients with GSD who are currently older than 18 years of age. Clinical, radiographic, and laboratory findings at the latest visit were obtained, but data were not universally available for every item on the questionnaire. In analyzing each response, information was considered to be available only if specifically recorded; omission of information was not recorded as either a negative or a positive response. The presence of liver adenomas, nephrocalcinosis, or kidney stones was based on data from ultrasound or radiographic studies. The diagnosis of osteopenia was based on data from radiographic studies. The normal values for height were taken from the National Center for Health Statistics [12]. Normal values for serum chemistry tests [13] were used. Results Glycogen Storage Disease Type Ia Case Report Patient 1, a 43-year-old divorced father of one child, is a poultry farmer. A liver biopsy and enzymatic assay were obtained at 4 years of age because of poor growth, hypoglycemia without seizures, hepatomegaly, and frequent nosebleeds. Despite frequent meals, growth continued to be poor, puberty was delayed, and the final adult height of 168 cm was achieved after 20 years of age. Allopurinol was taken inconsistently after one of many gouty attacks beginning from 18 years of age. The patient did not complete high school. As an adult, he has smoked 2 to 4 packs of cigarettes per day. After divorcing in his 20s, he frequently skipped breakfast and failed to follow a recommended diet. Instead, his diet was high in fat and consisted primarily of foods that required little preparation, such as candy and sandwiches. He has always denied symptomatic hypoglycemia, although his serum glucose concentration after an overnight fast is about 2.8 mmol/L (50 mg/dL). Beginning in his mid-20s, he had recurrent episodes of flank pain and hematuria that were treated with antibiotics, and he passed kidney stones. At age 24, an intravenous pyelogram showed punctate calcificati

A progressive neurologic syndrome in children with chronic liver disease.

A progressive neurologic syndrome developed in six children with longstanding cholestatic liver disease. The neurologic abnormalities included areflexia, gait disturbance, decreased proprioceptive and vibratory sensation, and paresis of gaze. Serum vitamin E concentrations were uniformly low. Neuropathological studies carried out in two of the three fatal cases revealed degeneration of the posterior column, selective loss of large-caliber, myelinated axons in peripheral nerve, and spheroids in the gracile and cuneate nuclei. These lesions are similar to those found in animals with experimentally induced vitamin E deficiency. We therefore speculate that the neurologic syndrome in these children may be the result of chronic vitamin E malabsorption.

Mutations in CTC1, Encoding the CTS Telomere Maintenance Complex Component 1, Cause Cerebroretinal Microangiopathy with Calcifications and Cysts

Cerebroretinal microangiopathy with calcifications and cysts (CRMCC) is a rare multisystem disorder characterized by extensive intracranial calcifications and cysts, leukoencephalopathy, and retinal vascular abnormalities. Additional features include poor growth, skeletal and hematological abnormalities, and recurrent gastrointestinal bleedings. Autosomal-recessive inheritance has been postulated. The pathogenesis of CRMCC is unknown, but its phenotype has key similarities with Revesz syndrome, which is caused by mutations in TINF2, a gene encoding a member of the telomere protecting shelterin complex. After a whole-exome sequencing approach in four unrelated individuals with CRMCC, we observed four recessively inherited compound heterozygous mutations in CTC1, which encodes the CTS telomere maintenance complex component 1. Sanger sequencing revealed seven more compound heterozygous mutations in eight more unrelated affected individuals. Two individuals who displayed late-onset cerebral findings, a normal fundus appearance, and no systemic findings did not have CTC1 mutations, implying that systemic findings are an important indication for CTC1 sequencing. Of the 11 mutations identified, four were missense, one was nonsense, two resulted in in-frame amino acid deletions, and four were short frameshift-creating deletions. All but two affected individuals were compound heterozygous for a missense mutation and a frameshift or nonsense mutation. No individuals with two frameshift or nonsense mutations were identified, which implies that severe disturbance of CTC1 function from both alleles might not be compatible with survival. Our preliminary functional experiments did not show evidence of severely affected telomere integrity in the affected individuals. Therefore, determining the underlying pathomechanisms associated with deficient CTC1 function will require further studies.

Hepatic fructose-1,6-diphosphatase deficiency: A cause of lactic acidosis and hypoglycemia in infancy

An 8-month-old female, maintained on breast feeding for 6 months, experienced numerous attacks of hyperventilation when weaned to baby food and was admitted with severe lactic acidosis (20 mM) and hypoglycemia. Physical examination was negative except for hepatomegaly. Fasting (18 hr) after stabilization on a high carbohydrate diet resulted in hypoglycemia (plasma glucose 40 mg/100 ml), lactic acidosis (6-10 mM), and a rise in plasma alanine. Glucagon produced a glycemic response after 6 hr, but not after 18 hr fasting. Intravenous galactose increased plasma glucose (Delta 45 mg/100 ml) but intravenous fructose, glycerol, and alanine caused a 40-50% fall in plasma glucose and a significant rise in lactate (Delta 3-4 mM). Liver biopsy showed fatty infiltration. Liver slices incubated with galactose, lactate, fructose, alanine, or glycerol converted only galactose to glucose. Hepatic glycolytic intermediates were increased below the level of fructose-1,6-diphosphate and decreased above. Hepatic phosphorylase, glucose-6-phosphatase, amylo-1,6-glucosidase, phosphofructokinase, fructose-1-phosphate aldolase, and fructose-1,6-diphosphate aldolase levels were normal, but no fructose-1,6-diphosphatase (FDPase) activity was detected. Further studies on the liver homogenate of this patient revealed the presence of an acid-precipitable activator of FDPase. Normal plasma glucose and lactate levels were maintained on an 800 cal diet of 66% carbohydrate (sucrose and fructose excluded). 5% protein, and 20% fat. When carbohydrate was reduced to 35% and protein or fat increased to 23 and 53% respectively, lactic acidosis and hypoglycemia recurred. These studies show that a deficiency of FDPase produced infantile lactic acidosis and hypoglycemia and can be controlled by an appropriate diet.

Upper Gastrointestinal Endoscopy in the Pediatric Patient

The value of upper gastrointestinal endoscopy in adults is well established. This study of 50 children demonstrates that upper gastrointestinal endoscopy can be performed safely and effectively in this age group without general anesthesia. Endoscopy appears more sensitive than radiology in the detection not only of superficial mucosal lesions, but of gastric and duodenal ulcers as well.

Antral diaphragm—a cause of gastric outlet obstruction in infants and children

Gastric outlet obstruction in infants and children may be due to a partial, prepyloric antral diaphragm. Twelve new patients are added to the 32 described previously. Onset of symptoms varied from shortly after birth to five years. Nonbilious vomiting was the most common presenting symptom. Radiographic evaluation requires specific technique for demonstration of the web and to differentiate this from pylorospasm and pyloric stenosis. Gastroscopy was employed in three patients. Repair usually consisted of incision of the web and construction of a patulous gastric outlet. All patients remained asymptomatic after operation. The etiology of the webs remains unknown, but they may result from an excessive local endodermal proliferation early in gastric development.

Complete Genomic Structure and Mutational Spectrum of PHKA2 in Patients with X-Linked Liver Glycogenosis Type I and II

X-linked liver glycogenosis (XLG) is probably the most frequent glycogen-storage disease. XLG can be divided into two subtypes: XLG I, with a deficiency in phosphorylase kinase (PHK) activity in peripheral blood cells and liver; and XLG II, with normal in vitro PHK activity in peripheral blood cells and with variable activity in liver. Both types of XLG are caused by mutations in the same gene, PHKA2, that encodes the regulatory alpha subunit of PHK. To facilitate mutation analysis in PHKA2, we determined its genomic structure. The gene consists of 33 exons, spanning >/=65 kb. By SSCP analysis of the different PHKA2 exons, we identified five new XLG I mutations, one new XLG II mutation, and one mutation present in both a patient with XLG I and a patient with XLG II, bringing the total to 19 XLG I and 12 XLG II mutations. Most XLG I mutations probably lead to truncation or disruption of the PHKA2 protein. In contrast, all XLG II mutations are missense mutations or small in-frame deletions and insertions. These results suggest that the biochemical differences between XLG I and XLG II might be due to the different nature of the disease-causing mutations in PHKA2. XLG I mutations may lead to absence of the alpha subunit, which causes an unstable PHK holoenzyme and deficient enzyme activity, whereas XLG II mutations may lead to in vivo deregulation of PHK, which might be difficult to demonstrate in vitro.

Prepyloric gastric antral web: a puzzling epidemic.

Antral webs and diaphragms are considered a rare cause of gastric outlet obstruction in infants and children. A radiographic diagnosis of antral web was made in 28 children during a 26-mo period. Nonbilious, often projectile vomiting was the predominant presenting symptom in 24 infants who were less than 6 mo of age. The older children complained of pain, vomiting, fullness after eating, and eructation. The characteristic radiologic finging was a wirelike transverse septum 1--2 cm proximal to the pylorus. Poor antral filling was an important early clue in the radiographic search for the webs. Pyloroplasty was performed in 20 patients, frequently after failure of medical management of symptoms. Coexistent congenital abnormalities were present in 28% of patients. A search for environmental and familial factors has failed to elucidate any teratogenic influences in this population.

Perforated stress ulcers in infants

During a 5-yr period, 10 infants less than 1 yr of age developed gastroduodenal perforation during treatment for severe underlying illness. Brisk gastrointestinal hemorrhage preceded perforation in most patients. In contrast to stress ulceration in adults, infants appear to have a higher frequency of single ulcers, perforation, and duodenal (rather than gastric) location. The mortality of 40% in this group, and in those patients reported in the literature who have been treated since 1960, implies that effective preventive and therapeutic measures are not yet available and also emphasizes the serious nature of the underlying disorder.