The initial treatment requires performing a "leveling" colostomy in the most distal colon with ganglion cells present. This requires exploration laparatomy with multiple seromuscular biopsies of the colon wall to determine the exact extend of the aganglionosis. The colostomy is placed above the transition zone. Placement of the colostomy in an area of aganglionosis will lead to persistent obstruction
Once the child has reached an adequate size and age (6-12 months; 20 pounds or more), a formal pull-through procedure is done. Three pull-through procedures are currently in use for treating Hirschsprung's disease. The first of these is the original Swenson procedure, in which the aganglionic rectum is carefully dissected in the pelvis and removed down to the anus. The ganglionic colon is then anastomosed to the anus via a perineal approach. In the Duhamel procedure, dissection outside the rectum is confined to the retrorectal space, and the ganglionic colon is anastomosed posteriorly just
above the anus. The anterior wall of the ganglionic colon and the posterior wall of the aganglionic rectum are anastomosed, using a stapling device. In Soave's operation, dissection is entirely within the rectum. The rectal mucosa is stripped from the muscular sleeve, and the ganglionic colon is brought through this sleeve and anastomosed to the anus. Complications with all procedures include enterocolitis, constipation and anastomotic stricture, but long-term results with the three procedures are comparable and generally excellent in experienced hands. These three procedures also can be
adapted for total colonic aganglionosis; the ileum is used for the pull-through or anastomosed to the aganglionic segment of distal colon and rectum to improve absorption.
Sunday, 26 June 2011
Thursday, 23 June 2011
Wednesday, 22 June 2011
Investigation
Infants with Hirschsprung's disease usually will fail to pass meconium in the first 24 h of life, although this history is often difficult to obtain. Barium enema may be unreliable in diagnosing Hirschsprung's disease in the newborn infant because the colon is not dilated enough to show a transition zone. In older infants and children, barium enema will show the size difference between the dilated ganglionic colon and the distal constricted aganglionic rectal segment. The barium enema in total colonic aganglionous usually shows a markedly shortened colon.
Rectal biopsy makes the definitive diagnosis of Hirschsprung's disease. Suction rectal biopsy provides a small piece of mucosa and submucosa without the requirement for anesthesia. Occasionally the suction biopsy is not diagnostic and a full-thickness biopsy is required. The histopathology of Hirschsprung's disease is the absence of ganglion cells in the myenteric plexuses, increased staining of a cholinesterase stain and the presence of hypertrophied nerve bundles. Some surgeons have found the use of rectal manometry helpful, particularly in older children, but it is not as accurate a diagnostic tool as is rectal biopsy. Some centers employ manometry, histochemical studies or special stains for diagnosis. These special studies are only as good as the person performing them and interpreting the results
Infants with Hirschsprung's disease usually will fail to pass meconium in the first 24 h of life, although this history is often difficult to obtain. Barium enema may be unreliable in diagnosing Hirschsprung's disease in the newborn infant because the colon is not dilated enough to show a transition zone. In older infants and children, barium enema will show the size difference between the dilated ganglionic colon and the distal constricted aganglionic rectal segment. The barium enema in total colonic aganglionous usually shows a markedly shortened colon.
Rectal biopsy makes the definitive diagnosis of Hirschsprung's disease. Suction rectal biopsy provides a small piece of mucosa and submucosa without the requirement for anesthesia. Occasionally the suction biopsy is not diagnostic and a full-thickness biopsy is required. The histopathology of Hirschsprung's disease is the absence of ganglion cells in the myenteric plexuses, increased staining of a cholinesterase stain and the presence of hypertrophied nerve bundles. Some surgeons have found the use of rectal manometry helpful, particularly in older children, but it is not as accurate a diagnostic tool as is rectal biopsy. Some centers employ manometry, histochemical studies or special stains for diagnosis. These special studies are only as good as the person performing them and interpreting the results
Tuesday, 21 June 2011
Clinical features
The presentation may be much subtle, with constipation and abdominal distention as the chief findings. Symptoms usually begin at birth, frequently with delayed passage of meconium. Any newborn who fails to pass meconium in the first 24-48 hours of life should be evaluated for possible Hirschsprung's disease. In some infants, the presentation is that of complete intestinal obstruction. Others have relatively few symptoms until several weeks of age, when the classic symptom of
constipation has its onset. Diarrhea is not uncommon but differs from the usual infantile diarrhea in that it is associated with abdominal distension. Occasionally the patient will go many years with mild constipation and diagnosis will be delayed. Occasionally failure to thrive is the initial sign.
The diagnosis is first suspected based on history and physical examinations (characteristically there is no stool in rectum and abdominal distension is painless).
The presentation may be much subtle, with constipation and abdominal distention as the chief findings. Symptoms usually begin at birth, frequently with delayed passage of meconium. Any newborn who fails to pass meconium in the first 24-48 hours of life should be evaluated for possible Hirschsprung's disease. In some infants, the presentation is that of complete intestinal obstruction. Others have relatively few symptoms until several weeks of age, when the classic symptom of
constipation has its onset. Diarrhea is not uncommon but differs from the usual infantile diarrhea in that it is associated with abdominal distension. Occasionally the patient will go many years with mild constipation and diagnosis will be delayed. Occasionally failure to thrive is the initial sign.
The diagnosis is first suspected based on history and physical examinations (characteristically there is no stool in rectum and abdominal distension is painless).
Wednesday, 15 June 2011
Pathology
Hirschsprung's disease (HD) is characterized by lack of enteric ganglion cells, hyperplasia of abnormal nerve fibers and a non-propulsive, non-relaxing segment of bowel. Classically the etiology is attributed to a failure of cranio-caudal migration of parasympathetic neural crest cells to the distal bowel. Hirschsprung's is the congenital absence of parasympathetic innervation of the distal intestine. Aganglionic colon does not permit normal peristalsis to occur. Functional obstruction therefore supervenes, and the infant may present with complete colon obstruction or with a devastating enterocolitis. The colon proximal to the aganglionic segment, in an effort to overcome the partial
obstruction, becomes distended and its wall markedly thickened because of muscle hypertrophy. A plausible explanation for the failure of relaxation of the bowel involved is a deficiency of enteric inhibitory nerves that mediates the relaxation phase of peristalsis. These nerves are intrinsic to the gut and are classify as non-adrenergic and non-cholinergic. Nitric oxide (NO) has recently been implicated as the neurotransmitter which mediates the relaxation of smooth muscle of the GI tract in HD. It's absence
in aganglionic bowel might account for the failure of relaxation during peristalsis. Besides, adhesions molecules (absent in aganglionic bowel) during early embryogenesis might restrict the neuro-ectodermal origin involved in the initial contact between nerves and muscle cell (synaptogenesis) suggesting that developmental anomaly of innervated muscle and absent NO causes the spasticity characteristic of HD.
Hirschsprung's disease (HD) is characterized by lack of enteric ganglion cells, hyperplasia of abnormal nerve fibers and a non-propulsive, non-relaxing segment of bowel. Classically the etiology is attributed to a failure of cranio-caudal migration of parasympathetic neural crest cells to the distal bowel. Hirschsprung's is the congenital absence of parasympathetic innervation of the distal intestine. Aganglionic colon does not permit normal peristalsis to occur. Functional obstruction therefore supervenes, and the infant may present with complete colon obstruction or with a devastating enterocolitis. The colon proximal to the aganglionic segment, in an effort to overcome the partial
obstruction, becomes distended and its wall markedly thickened because of muscle hypertrophy. A plausible explanation for the failure of relaxation of the bowel involved is a deficiency of enteric inhibitory nerves that mediates the relaxation phase of peristalsis. These nerves are intrinsic to the gut and are classify as non-adrenergic and non-cholinergic. Nitric oxide (NO) has recently been implicated as the neurotransmitter which mediates the relaxation of smooth muscle of the GI tract in HD. It's absence
in aganglionic bowel might account for the failure of relaxation during peristalsis. Besides, adhesions molecules (absent in aganglionic bowel) during early embryogenesis might restrict the neuro-ectodermal origin involved in the initial contact between nerves and muscle cell (synaptogenesis) suggesting that developmental anomaly of innervated muscle and absent NO causes the spasticity characteristic of HD.
Saturday, 11 June 2011
Epidemiology
HD occurs 1 in 1000-1500 live births with a 4:1 male predominance. 96% are term appropriate for gestation age (TAGA), 4% are prematures
Friday, 10 June 2011
Hirschsprung's Disease
IntroductionHirschsprung's disease (HD) is a form of functional intestinal obstruction that results from the absence of ganglion cells in the myenteric plexus of the intestine. The precursors of the ganglion cells are neural crest cells that migrate into the intestine from cephalad to caudad. The process is completed by the twelfth week of embryonic life, but the migration from midtransverse colon to anus takes 4 weeks. This increases the time period of vulnerability for failure of migration and accounts for the fact that most cases of aganglionosis involve the rectum and rectosigmoid. Longer segments of absent ganglion cells also may occur, and total colonic aganglionosis, although rare, is also seen.
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