What is the pathophysiology of Hirschsprung disease?
Hirschsprung disease results from the absence of enteric neurons within the myenteric and submucosal plexus of the rectum and/or colon. Enteric neurons are derived from the neural crest and migrate caudally with the vagal nerve fibers along the intestine.
What is the pathophysiology of Aganglionic Megacolon?
Hirschsprung disease (HD) is a motor disorder of the gut, which is caused by the failure of neural crest cells (precursors of enteric ganglion cells) to migrate completely during intestinal development during fetal life. The resulting aganglionic segment of the colon fails to relax, causing a functional obstruction.
Why is there poor bowel motility with Hirschsprung’s disease?
In Hirschsprung disease a part of the large intestine lacks normal nerve cells. This means that digested food and stool can’t move forward through that part of the digestive tract. The large intestine becomes blocked with stool.
What is the other name of Hirschsprung disease?
Hirschsprung’s disease is a rare congenital disorder that causes an obstruction (or blockage) of the intestine. This prevents normal bowel movements. You might hear doctors refer to this condition with other names, such as: Congenital megacolon or megarectum.
How do you diagnose Hirschsprung’s disease?
Rectal biopsy: This test gives the definitive diagnosis. It involves taking a sample of the cells in the rectum for a pathologist to view under a microscope. The pathologist confirms that a child has Hirschsprung disease based on the absence of ganglion cells and other abnormal nerve-related findings.
Is Hirschsprung disease autosomal dominant?
If HSCR occurs as part of a genetic syndrome, then it is inherited in a specific pattern, according to the specific syndrome . For example, the inheritance may be autosomal recessive , autosomal dominant , or X-linked recessive , depending on the exact cause of the syndrome.
What is the rectosigmoid ratio?
The rectosigmoid ratio is a measurement of the diameter of the rectum divided by that of the sigmoid colon during contrast enema. It is of particular use in the diagnosis of Hirschsprung disease. Normal children have a rectum that is larger than the sigmoid (i.e. rectosigmoid ratio >1).
What is the significance of the sigmoid ratio in the colon?
It is of particular use in the diagnosis of Hirschsprung disease. Normal children have a rectum that is larger than the sigmoid (i.e. rectosigmoid ratio >1). In fact the rectum has the largest diameter of the left side of the colon.
Which biopsy findings are characteristic of Hirschsprung disease?
A definitive diagnosis requires a full thickness rectal biopsy. Hirschsprung disease is characterized by aganglionosis (absence of ganglion cells) in the distal colon and rectum. It is thought to either occur from a failure of neuroblasts in neural crest cells to migrate into bowel segments or degeneration of already migrated neuroblasts.
What is the mortality and morbidity associated with Hirschsprung’s enterocolitis?
Increased intraluminal pressure can lead to decreased blood flow and deterioration in the mucosal layer. This stasis can lead to bacterial proliferation and the subsequent complication of Hirschsprung’s enterocolitis, which has a mortality rate of 25-30%.