Hirschsprung's disease is the most common cause of pediatric intestinal obstruction. Contrast enema is used for evaluation of the patients with its diagnosis.
To evaluate sensitivity, specificity, positive predictive value, and negative predictive value of radiologic findings for diagnosis of Hirschsprung in patients underwent barium enema.
This cross sectional study was carried out in Imam Khomeini Hospital for one year starting from 2012, April. Sixty patients were enrolled. Inclusion criteria were: neonates with failure to pass meconium, abdominal distention, and refractory constipation who failed to respond with medical treatment. Transitional zone, delay in barium evacuation after 24 h, rectosigmoid index (maximum with of the rectum divided by maximum with of the sigmoid; abnormal if <1), and irregularity of mucosa (jejunization) were evaluated in barium enema. Biopsy was obtained at three locations apart above dentate line. PPV, NPV, specificity , and sensitivity was calculated for each finding.
Mean age of the cases with Hirschsprung's disease and without was 17.90±18.29 months and 17.8±18.34 months respectively (p=0.983). It was confirmed in 30 (M=20, F=10) of cases. Failure to pass meconium was found in 21(70%) cases. Sensitivity, specificity, PPV, and NPV were 90%, 80%, 81.8% and 88.8% respectively for transitional zone in barium enema. Sensitivity, specificity, PPV, and NPV were 76.7%, 83.3%, 78.1% and 82.1% respectively for rectosigmoid index .Sensitivity, specificity, PPV, and NPV were 46.7%, 100%, 100% and 65.2% respectively for irregular contraction detected in barium enema. Sensitivity, specificity, PPV, and NPV were 23.3%, 100%, 100% and 56.6% respectively for mucosal irregularity in barium enema.
The most sensitive finding was transitional zone. The most specific findings were irregular contraction, mucosal irregularity, and followed by cobblestone appearance.
Researches on Chagas disease still use several animals and rats, due to size and susceptibility were preferred by many authors.
To develop an experimental model of megacolon in rats inoculated with the strain Y of Trypanosoma cruzi.
Thirty male Wistar rats were distributed in three groups inoculated with different inoculants: Group A: 600000, Group B: 1000000 and Group C: 1500000 blood trypomastigotes of T. cruzi. Animals were sedated intramuscularly at zero inoculation time (T0) and 60 days after inoculation (T60), to perform the barium enema in order to evaluate the dilatation of the different segments of colon in a comparative study of the measurements obtained, using a digital caliper. Evidence of infection was performed by blood smear collected from the animal’s tail 18 days after inoculation with observation of blood forms.
Comparing the intestinal diameter of the inoculated animals with 60,0000 trypomastigotes in the T0 of infection with T60 days after the inoculation, significant dilatation was observed between the proximal, medial and distal segments (p<0.01), indicating the establishment of the megacolon model. In addition, comparing intestinal diameter between the different segments, with in the T0 of infection and the T60 after inoculation, significant alterations were observed (p<0.05).
The proposed model was possible for in vivo studies of alterations due to infection by T. cruzi and functional alterations of the colon. In addition, the changes manifested in the colon are not directly proportional to the size of the inoculum, but to the time of infection that the animals were submitted, since the animals inoculated with 60,0000 blood forms were the ones which presented the most significant alterations.
Developed by Surya MKT