disease of small and large intestine Flashcards
What are the differences between atresia and stenosis in intestinal obstruction?
Atresia involves complete obstruction of the intestine, while stenosis refers to incomplete obstruction. Atresia results from developmental failure, intrauterine vascular accidents, or intussusception.
Describe the pathogenesis and clinical features of Hirschsprung disease.
Hirschsprung disease is a congenital disorder characterized by aganglionosis of a portion of the intestinal tract. It results from the arrest of neural crest cell migration or premature death of ganglion cells. Clinical features include immediate neonatal constipation, failure to pass meconium, chronic constipation, abdominal distension, and potential complications like enterocolitis and fluid-electrolyte disturbances.
What histological changes are observed in Hirschsprung disease?
Histologically, Hirschsprung disease shows the absence of ganglion cells in the affected intestinal segment, hypertrophy of nerve fibers, stenosis of the aganglionic segment, and dilation of the proximal bowel.
Explain the pathogenesis of diverticular disease and its clinical manifestations.
Diverticular disease is an acquired condition involving outpouching of the colonic mucosa and submucosa. It results from focal weakness of the colonic wall and increased intraluminal pressure. Clinical manifestations include asymptomatic cases, lower abdominal pain, constipation, tenesmus, and potential complications like diverticulitis, obstruction, and pericolic abscess formation.
What are the macroscopic and microscopic features of ischemic bowel disease?
Macroscopically, ischemic bowel disease presents with dusky-colored to hemorrhagic small bowel segments. Microscopically, mild cases show erosion of the surface epithelium and congestion of the lamina propria blood vessels, while severe cases exhibit transmural hemorrhage and necrosis.
Discuss the classification and causes of intestinal obstruction.
Intestinal obstruction can be classified as mechanical (structural obstruction) or functional (ileus). Mechanical obstruction results from blockages preventing food movement, while functional obstruction occurs without physical blockage. Causes include muscle or nerve damage, infections, and certain medications.
What are the symptoms and signs of intestinal obstruction?
Symptoms include intermittent or colicky abdominal pain, vomiting, distension of the stomach, and constipation or absence of flatus.
Describe the types of inguinal hernias and their characteristics.
Inguinal hernias include indirect and direct types. Indirect hernias are congenital, enter the inguinal canal through the deep inguinal ring, and are more common in males. Direct hernias bulge anteriorly through weak areas in the abdominal wall and are common in older men with weak abdominal muscles.
