INTRODUCTION
The formation of the enteric nervous system (nervous system of the gut) is an important step in human development. The smooth muscle in the gut must be stimulated by the a part of the nervous system called the parasympathetic nervous system for digestion to occur. Nerves extend the entire length of the digestive tract, allowing material to be pushed all the way through the gastrointestinal (GI) tract by peristaltic contractions of the gut. Skip-segment Hirschsprung’s Disease (SSHD) is a developmental abnormality in which one (or more) normally ganglionic (contains functional nervous tissue) area(s) of intestine (beginning at the distal rectum) is/are surrounded on both sides by sections that lack ganglionization (no functional nervous tissue) and cannot contract and relax normally (1).
Diagnosis of SSHD typically occurs soon after birth by rectal suction biopsies, with newborns presenting a variety of symptoms including constipation, bilious vomiting, pain/swelling in the abdomen, and a failure to pass meconium (the first stool of an infant that consists of substances ingested by the infant’s time in the womb) (1). The rectal suction biopsy would detect aganglionosis and a few other medical abnormalities. Enterocolitis, an intestinal infection, and megacolon, a distension of the colon due to buildup of faecal matter, can be other effects of SSHD due to the tonic contraction of smooth muscle tissue in the area of aganglionosis (2). As seen in Figure 1, faecal matter builds up in the area just cranial to the aganglionosis since it can’t be pushed through the constriction by peristaltic contraction generated by the ganglionic sections of the intestines.
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It’s an extremely rare congenital malformation, with only 24 cases reported since 1954. This notable rarity has caused many physicians to doubt the existence of SSHD until their own patients exhibit the condition (1). The almost mythical status of SSHD has probably led to many cases going unreported, possibly being chalked up to the more standard Hirschsprung’s Disease (HSCR) or some other intestinal disorder. The areas of aganglionosis varied among the 24 patients, 18 of whom were male and this pattern of higher occurrence in males is consistent with regular HSCR (4). The rate of regular HSCR is 1/5000 live births, so the skip-segment variety is an extremely rare variant (4).