Michael S. Irish

THE APPROACH TO COMMON ABDOMINAL DIAGNOSES IN INFANTS AND CHILDREN

This article focuses on salient points in the evaluation of abdominal pain in infants and children. Specifically, the authors address appendicitis and abdominal pain associated with either vomiting, constipation, or gastrointestinal bleeding. A discussion of common abdominal masses, urologic, and gynecologic problems, and considerations in the evaluation of immunologically suppressed or neurologically impaired children, and children with recurrent abdominal pain is also presented. The authors establish logical, focused approaches to the initial evaluation and management of abdominal pain and suggest criteria for timely surgical referral.

Congenital diaphragmatic hernia : A historical review

Congenital diaphragmatic hernia (CDH) has been described, studied, and treated for over 400 years. A historical perspective is given. Great strides have been made in the care of patients with CDH; however, the mortality rate remains 30% to 60%. Consideration of historical references, observations, and achievements in the study of CDH is important for the continued advancement and improvement in our understanding of and future success in treating infants and children with CDH.

Prenatal diagnosis of the fetus with cystic fibrosis and meconium ileus

The sonographic finding of hyperechoic or dilated fetal bowel raises suspicion of a number of prenatal disorders including meconium ileus (MI), meconium peritonitis, congenital infection, neoplasm, or chromosomal trisomy. These findings may also represent transient normal variants. The following case report details the evaluation of one pregnancy with abnormal intestinal echogenic findings on serial sonograms (US), to demonstrate inherent diagnostic difficulties in such a case. A diagnostic algorithm is presented to aid in the proper use of US and DNA mutation analysis for cystic fibrosis (CF), so that the cause of an abnormal abdominal US can be established earlier and more accurately than suggested by previous management schemes. Earlier fetal diagnosis may help to anticipate postnatal problems associated with CF/MI, and therefore provide more optimal clinical management of the affected fetus.

Observation of splenic trauma : When is a little too much?

A 12-year-old boy was treated conservatively for a grade II splenic laceration. On discharge, he was instructed to avoid contact sports, running, and strenuous physical activity. Thirty-eight days later, after diving off the side of a swimming pool, he had abdominal pain, nausea, and diaphoresis. On admission, he was hemodynamically unstable. Results of a diagnostic lavage showed gross blood. At laparotomy, a fractured spleen was found, and splenectomy was performed. He recovered without complication. This case questions the activity restrictions placed on patients with conservatively managed splenic trauma. Avoidance of only contact sports and heavy exertion may be inadequate.

THE APPROACH TO COMMON ABDOMINAL DIAGNOSES IN INFANTS AND CHILDREN: Part II

Part I (August 1998 issue, Pediatric Clinics), discussed appendicitis and common abdominal diagnoses in infants and in children associated with vomiting, as well as special considerations in the evaluation of immunologically suppressed and neurologically impaired pediatric patients. In this article, the authors continue to discuss the evaluation of constipation, gastrointestinal bleeding, common abdominal masses, and recurrent abdominal pain.

Cervical ECMO cannula placement in infants and children: Recommendations for assessment of adequate positioning and function

BACKGROUND/PURPOSE Cervical extracorporeal membrane oxygenation (ECMO) cannula position is often difficult to confirm by chest x-ray alone. Malposition requires a second surgery to rectify the problem. Reoperation places the patient at risk for infection, bleeding, or death. This study analyzes indications for cannula repositioning and suggests an alternative standard for intraoperative evaluation of catheter function as it relates to position. METHODS The authors reviewed charts of 73 patients placed on arterio-venous ECMO through cervical vascular access. Reasons for repositioning of either cannula at the initial surgery or postoperatively were recorded. RESULTS Of 73 patients, 18 (24.6%) required either arterial cannula or venous cannula repositioning. In 10 (55%) of these patients, cannula malposition was not detected by chest x-ray during the initial cannulation, and they therefore required a second cervical exploration for repositioning. CONCLUSIONS Chest x-ray is not sensitive in demonstrating malpositioned cervical ECMO cannulae. Two-dimensional ECHO before wound closure, may be a superior, more cost effective means of assessing cannula placement and function than x-ray alone. Confirmation of cannula position and function, before wound closure, would reduce the risks involved with cervical reexploration.

Contractile properties of intralobar pulmonary arteries and veins in the fetal lamb model of congenital diaphragmatic hernia

BACKGROUND/PURPOSE Pulmonary hypertension plays a significant role in the pathophysiology of congenital diaphragmatic hernia (CDH). Although there has been an intensive research effort directed at mediators that may cause pulmonary vasoconstriction, no single agent has been identified. The authors hypothesize that there may be an alteration in the cGMP-nitric oxide (NO) pathway of vasodilatation contributing to the pulmonary hypertension observed in CDH. The purpose of these studies is to begin to elucidate vasoactive properties of pulmonary vessels with particular attention to the cGMP-NO pathway of vasodilatation in fetal lambs with CDH. METHODS Fourth-generation pulmonary arteries and pulmonary veins were dissected from both right and left lungs of eight, 139-day gestational fetuses with surgically created CDH. Vessels were studied with standard isolated tissue bath techniques. Experiments examined basal release of NO in endothelium-intact PVs and PAs of both right and left lungs by measuring the contractile force of vessels constricted with norepinephrine (NE) in the presence and absence of the nitric oxide synthase (NOS) inhibitor N(omega)-nitro-L-arginine (L-NA). Concentration-response curves to the vasodilating agents zaprinast and A23187 were also obtained in vessels contracted by NE. RESULTS Left and right pulmonary artery responses to NE are enhanced over those of historic controls. Pretreatment of left pulmonary arteries with L-NA enhances the vasoconstrictor response to NE, whereas right PAs show no increased response. Relaxation responses to A23187 and zaprinast, in both left and right pulmonary arteries were not different from control lambs. Relaxation responses of both left and right pulmonary veins to A23187 and zaprinast are blunted compared with controls. This blunting is significantly more in left pulmonary veins than right. Further, right but not left pulmonary veins display enhanced vasoconstrictive response to NE after L-NA pretreatment. CONCLUSIONS The NO-cGMP pathway of vasodilatation is abnormal in the near term, fetal lamb with CDH. These abnormalities were most apparent in pulmonary veins and may reflect abnormal NOS activity or content between left and right lungs of the fetal lamb with CDH. Pulmonary arteries from CDH lambs have basal and stimulated NO release equal to that of historic controls but appear to be hypersensitive to exogenous vasoconstrictors.

Lung physiological and metabolic changes in lambs with congenital diaphragmatic hernia after administration of prenatal maternal corticosteroids

BACKGROUND/PURPOSE Improved outcomes of preterm infants born to mothers treated prenatally with corticosteroids have been documented. The authors investigated the role of prenatal maternal corticosteroid therapy in congenital diaphragmatic hernia (CDH). METHODS Five CDH lambs of ewes given 0.5 mg/kg betamethasone intravenously 24 hours before delivery (single-dose), four CDH lambs of ewes similarly dosed at 48 and 24 hours before delivery (double-dose), five untreated CDH lambs and five control lambs were studied. After 2 hours of ventilation, compliance, arterial oxygen (PO2) and carbon dioxide (pCO2) concentrations were recorded. Lavage protein and phospholipid levels were measured, and lung tissue was analyzed for antioxidant enzyme activity (AOE). RESULTS No improvement in gas exchange was noted in either treatment group. Significant increases in compliance (P = .02) were noted in the double-dose steroid group, which were different from that of untreated CDH lambs or controls. Minimal changes in AOE activities were seen with steroid administration. CONCLUSIONS Although the metabolic changes were not significant, the marked improvement in compliance seen in the double-dosed steroid group suggests a potential role for prenatal maternal corticosteroids in CDH. Further timing and dosage studies are warranted in this model.

Bleeding in Children Caused by Gastrointestinal Vascular Lesions

Intestinal vascular malformations in infants and children are rare but must be considered in the differential diagnosis of gastrointestinal bleeding. Many vascular malformation syndromes have associated intestinal lesions. Localization of vascular lesions is essential for successful management. A variety of treatment options including laser photoablation, surgical resection, and other nonoperative therapies have been utilized to treat these disorders.

Tracheal ligation and mechanical ventilation do not improve the antioxidant enzyme status in the lamb model of congenital diaphragmatic hernia

BACKGROUND/PURPOSE The antioxidant enzyme (AOE) system is the primary intracellular defense system of the lung against oxygen toxicity. The authors recently demonstrated depressed levels of catalase, glutathione peroxidase, and superoxide dismutase in congenital diaphragmatic hernia (CDH) lambs compared with controls. The aim of this study was to determine whether tracheal ligation (TL) or mechanical ventilation (recently shown to stimulate growth and surfactant metabolism, respectively) could induce an elevation in AOE activity. METHODS Four nonventilated lambs with surgically created CDH and TL and five CDH lambs ventilated for 4 hours were studied. Lung tissue was analyzed for AOE and the results compared with untreated CDH lambs. RESULTS Both ventilation and TL failed to elevate AOE activity above that of untreated CDH lambs. CONCLUSIONS The data provide further evidence that TL does not improve lung metabolism or maturation. Mechanical ventilation, which often involves high oxygen delivery, is a necessary and often beneficial therapeutic modality. In the CDH neonate compromised not only by low baseline levels of the AOE, but also by an inability to induce enzyme synthesis in response to hyperoxia, mechanical ventilation may, by causing lung injury, be contributing to the high morbidity and mortality rate associated with CDH.