Hirschsprung's Disease

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Hirschsprung’s Disease : 

Hirschsprung’s Disease Dr.Harshavardhan.B Radiology PG TSMU 30.01.2010

What is it? : 

What is it? Hirschsprung's disease, or congenital aganglionic megacolon, involves an enlargement of the colon, caused by bowel obstruction resulting from an aganglionic section of bowel (the normal enteric nerves are absent) that starts at the anus and progresses upwards. The length of bowel that is affected varies but seldom stretches for more than about 30 cm. This disease is named after Harald Hirschsprung, the Danish physician who first described the disease in 1886

Intestinal Innervation : 

Intestinal Innervation The neurons of the ENS are collected into two types of ganglia: Myenteric (Auerbach's) and Submucosal (Meissner's) plexuses. Myenteric plexuses are located between the inner and outer layers of the muscularis externa, while Submucosal plexuses are located in the submucosa.

Slide 4: 

Auerbach's plexus (or myenteric plexus) exists between the longitudinal and circular layers of muscularis externa in the gastrointestinal tract and provides motor innervation to both layers and secretomotor innervation to the mucosa, having both parasympathetic and sympathetic input, whereas Meissner's plexus has only parasympathetic fibers.

Genetics : 

Genetics The RET proto-oncogene on chromosome 10 was identified as one of the genes involved Encoded by the gene EDNRB located on chromosome 13. Six other genes were discovered to be associated with Hirschsprung’s which are GDNF on chromosome 5, EDN3 on chromosome 20, SOX10 on chromosome 22, ECE1 on chromosome 1, NRTN on chromosome 19, and SIP1 on chromosome 2.

Clinical features : 

Clinical features 1) Delayed passage of meconium 2) Abdominal distension 3) Constipation Incidence of 1/5000 births Notably in males The enlarged section of the bowel is found proximally, while the narrowed, aganglionic section is found distally The absence of ganglion cells results in a persistent over-stimulation of nerves within the affected region, resulting in contraction.

Diagnosis : 

Diagnosis Suspect Hirschsprung's in a baby who has not passed meconium within 48 hours of delivery. Recall that 90% of babies pass their first meconium within 24 hours, and the next 9% within 48 hours. Definitive diagnosis is made by suction biopsy of the distally narrowed segment.

How is Hirschsprung's disease diagnosed? : 

How is Hirschsprung's disease diagnosed? Abdominal x-ray - a diagnostic test which may show a lack of stool in the large intestine or near the anus and dilated segments of the large and small intestine. Barium enema - a procedure performed to examine the large intestine for abnormalities. A fluid called barium (a metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an x-ray) is given into the rectum as an enema. An x-ray of the abdomen shows strictures (narrowed areas), obstructions (blockages), and dilated intestine above the obstruction. Anorectal manometry - a test that measures nerve reflexes which are missing in Hirschsprung's disease. Biopsy of the rectum or large intestine - a test that takes a sample of the cells in the rectum or large intestine and then looks for nerve cells under a microscope.

Slide 9: 

Hirschsprungs disease in contrast imaging

Treatment : 

Treatment Treatment of Hirschsprung's disease consists of surgical removal (resection) of the abnormal section of the colon, followed by reanastomosis.

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