Malrotation, malnutrition, and ischemic bowel disease

Intestinal malrotation in children: a problem-solving approach to the upper gastrointestinal series

Intestinal malrotation, which is defined by a congenital abnormal position of the duodenojejunal junction, may lead to midgut volvulus, a potentially life-threatening complication. An evaluation for malrotation is part of every upper gastrointestinal (GI) tract examination in pediatric patients, particularly neonates and infants. Although the diagnosis of malrotation is often straightforward, the imaging features in approximately 15% of upper GI tract examinations are equivocal and lead to a false-positive or false-negative interpretation. The clinical manifestations and upper GI tract findings of malrotation in older children and adults are less specific than are those in younger patients, and for this reason diagnosis of the condition may be more difficult. Successful differentiation between a normal variant and malrotation requires the use of optimal techniques in acquiring and interpreting the upper GI series. Familiarity with the upper GI series appearance of both normal and abnormal anatomic variants allows the radiologist to increase both diagnostic accuracy and confidence in the diagnosis of malrotation.

Disorders of intestinal rotation and fixation ("malrotation")

Malrotation with volvulus is one of the true surgical emergencies of childhood. Prompt radiological diagnosis is often paramount to achieving a good outcome. An understanding of the normal and anomalous development of the midgut provides a basis for understanding the pathophysiology and the clinical presentation of malrotation and malrotation complicated by volvulus. In this essay, the radiologic findings of malrotation and volvulus are reviewed and illustrated with particular attention to the child with equivocal imaging findings.

Midgut malrotation, the reliability of sonographic diagnosis

We are unaware of any other anatomical study which deals with normal variations in the relationship between the superior mesenteric artery (SMA) and the superior mesenteric vein (SMV). In our investigation in the majority of cases, the SMV lies to the right of the SMA. It has been suggested that ultrasonographic demonstration of a left sided SMV, is characteristic of midgut malrotation so a prospective study was undertaken in order to try to correlate the position of the mesenteric vessels on Ultrasound with the radiological diagnosis of midgut malrotation on upper GI series. 427 children (95% infants) who were planned for upper GI investigation, have had color Doppler U.S. of the mesenteric vessels before the barium study. In 67 cases, the mesenteric vessels were obscured by intestinal gas. Among them, there were 2 cases of malrotation. Three different positions of the mesenteric vessels were found in the 360 remaining cases. 1) A left sided SMV was found in 4% of the cases, all had midgut malrotation on X-rays and at surgery. 2) A mesenteric vein anterior to the SMA was found in 5% of the cases, 28% had midgut malrotation. 3) A normal right sided SMV was found in 91% of the cases. However 3% of these had midgut malrotation. There are anatomical variations in the position of the mesenteric vessels and a normal relationship between SMA and SMV does not exclude the possibility of intestinal malrotation. Nevertheless, ultrasound remains a useful noninvasive screening technique for the diagnosis of midgut malrotation.

Malrotation presenting beyond the neonatal period

The diagnosis of malrotation is easily made in the neonatal period, but is often delayed in older patients. Among 82 patients treated for malrotation in this institution, 45 patients presented with symptoms related to their malrotation, seven were diagnosed at exploration for concomitant intrinsic duodenal obstruction, and 30 patients had malrotations discovered as incidental findings at laparotomy or autopsy. Among the 45 symptomatic patients, 25 (56%) underwent surgery in the first month of life, whereas 20 patients (44%) underwent surgery at an older age. In this last group, the mean age at surgery was 51.5 months (range, 2 months to 16 years), the mean age of onset of symptoms was 2 years (range, 0 to 15 years) and the mean delay in diagnosis was 1.7 years. Although bilious vomiting was the presenting symptom among all patients undergoing surgery in the neonatal period, clinical features of older patients included intestinal obstruction (7), chronic abdominal pain (4), malabsorption/diarrhea (3), peritonitis/septic shock (2), solid food intolerance (1), common bile duct obstruction (1), abdominal distention (1), and delayed transit postappendectomy (1). The frequency of midgut volvulus was equal among both groups. Unusual forms of malrotation were more frequent in patients undergoing surgery beyond the neonatal period. In this group there was evidence of chronic venous and lymphatic obstruction with one case of superior mesenteric vein thrombosis and two cases of intestinal gangrene. A Ladd's procedure was performed in all cases and the most frequent postoperative complication was adhesive intestinal obstruction. There were no deaths. Awareness of the unusual presentation in patients who present beyond the neonatal period may help reduce delays in diagnosis and surgical treatment. We believe that laparotomy is indicated in all patients with malrotation, even if they are asymptomatic.

Malrotation of the intestines in children: the effect of age on presentation and therapy

Because of the devastating consequences of midgut volvulus as a result of malrotation, we reviewed the charts of 70 consecutive children to define the spectrum of presentation. Although 27 patients (39%) had presenting symptoms within the first ten days of life, 35 (50%) were older than 2 months of age. In general, the older children had a longer course of vague, antecedent symptoms such as intermittent, nonbilious vomiting and chronic abdominal pain. Associated congenital anomalies were common, with 32 patients (46%) presenting with 56 anomalies, the most prevalent of which were intestinal atresia, imperforate anus, duodenal web, and cardiac and orthopedic anomalies. Upper gastrointestinal (GI) series revealed the diagnosis in 29 cases (41%), as did contrast enema in 24 (34%). It is important to note that volvulus, intestinal gangrene, and mortality occurred regardless of age or chronicity of symptoms. Fifteen patients (21%) were discovered serendipitously while being evaluated and treated for seemingly unrelated conditions. No morbidity of mortality occurred in those patients who underwent subsequent semielective Ladd's procedure. The majority of morbidity and all seven mortalities occurred in patients with volvulus and intestinal necrosis. This study emphasizes the need for consideration of Ladd's procedure for children of all ages. In addition, due to the broad range of initial symptoms, a high index of suspicion is required in evaluating children with possible malrotation. Because it remains impossible to predict which patients will have catastrophic complications (based on age or type of presentation), we urge that even incidentally discovered patients with intestinal malrotation undergo Ladd's procedure.

Intestinal ischemia: treatment by peritoneal lavage with oxygenated perfluorochemical

Though the delivery of elemental oxygen to tissues ravaged by anaerobic infection may be useful, little data exists that suggests that such therapy may benefit ischemic tissue. We report the development of a model to test the question that peritoneal lavage with an oxygen containing solution may favorably influence occlusive intestinal ischemia. Adult Sprague-Dawley rats with Nembutal (sodium pentobarbital) anesthesia underwent midline laparotomy; a microvascular clamp was applied to the superior mesenteric artery (SMA); and an inflow and outflow lavage catheter was placed. Treatment groups included control rats undergoing SMA occlusion only without lavage, rats lavaged with albumin during SMA occlusion (medium control), and rats lavaged during SMA occlusion with oxygenated perfluorochemical FC-47 emulsified in albumin (O2-FC-47). The increase in serum L-lactate following occlusion was used as an index of intestinal injury whether the perfusate was maintained at room temperature (28 degrees C) or body temperature (37 degrees C). Beginning with time O, which corresponded to the time of unclamping, subsequent samples were collected at 15, 30, and 60 minutes after a 30-minute SMA occlusion. Sequential lactates in 13 control rats were 4.18, 4.10, 3.88, and 4.52 mmol/L. Albumin lavaged animals had values at 28 degrees C of 2.23, 1.35, 1.8, and 2.44 mmol/L and values at 37 degrees C of 2.22, 1.40, 2.07, and 3.21 mmol/L, respectively. With O2-FC-47 lavage the respective lactates were 1.89, 1.09, 1.32, and 1.44 mmol/L at 28 degrees C and 2.14, 2.19, 2.50, and 2.1 mmol/L at 37 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunodepression secondary to malnutrition: assay by lymphocyte subset analysis using monoclonal antibodies and the cell sorter

It has been well documented that the hospitalized child frequently is malnourished, and the considerably greater morbidity and mortality of such children, in large part, is due to the associated secondary immunodepression. To assess the mechanism of such immunodepression in acute and chronically malnourished subjects, we chose an experimental murine model of malnutrition. Immune function was assayed by lymphocyte subset population and mixed lymphocyte culture (MLC) assessment, determining whether an alteration of the T helper (TH) to T suppressor-cytotoxic (TS-C) lymphocyte ratio is the mechanism that produces immunoincompetence in malnutrition. Ten-week-old A/J mice were rendered acutely or chronically malnourished by graded protein restriction using a 2.5% protein diet. These animals were studied before and after protein depletion with the fluorescent activated cell sorter (FACS) and the MLC. FACS cell populations were defined by the monoclonal antibodies to THY 1.2, LYT 1 (TH), and LYT 2 (TS-C) antigens. MLC reactivity was assessed with A/J v C 57 BL/6 mouse lymphocytes and expressed as a stimulation index (S.I.). Results are expressed in Table 1, and suggest that these malnourished animals were significantly immunodepressed as measured in the MLC reaction. However, the mechanism of this depression is not mediated by an inversion of the TH/TS-C ratio. These data contrast with those previously reported for the immunodepression of the burned or traumatized patient in which the TH/TS-C ratios are reversed; these data suggest that a different, as yet to be elucidated, mechanism exists for the immunodepression of malnutrition.