Diagnosis and therapy of ultrashort Hirschsprung's disease.

BACKGROUND: Although ultrashort Hirschsprung's disease (UHD) was enzyme-histochemically characterised about 35 years ago, its existence is still often ignored. The aim of this study is to summarise the clinical diagnostic, incidence, gender ratio, morphological characteristics, and therapy over 15 years.

METHODOLOGY: The reliable diagnosis of suspected UHD requires a minimal enema of contrast medium to exclude Hirschsprung's disease (HD). In UHD during pressing or crying no reflux of contrast medium is observed. Final proof of UHD is an enzyme-histochemical biopsy examination of distal rectal mucosa. The biopsies must demonstrate submucosa and be taken from the dentate line and 1 cm, 2 cm, 4 cm and 6 cm above the dentate line. The cryostat sections must be cut 15 microm thick; this thickness is reduced to 4.5 microm by the thawing, spreading and drying of the sections on microscope slides. A reliable diagnosis of UHD needs an enzyme-histochemical acetylcholinesterase reaction of native sections of rectal mucosa.

RESULTS: UHD develops with first symptoms of chronic constipation in the second half of the first year of life. The chronic constipation proves to be therapy resistant. In HD constipation occurs in the first weeks of life or after weaning. In contrast to HD, no nerve fibres with increased AChE activity are observed in the lamina propria mucosa. Nets of nerve fibres with increased AChE activity can be found only in the muscularis mucosa and the musculus corrugator cutis ani (MCCA). The therapy of choice has proven to be a partial myectomy of the distal internal sphincter if dilatation of the internal sphincter was ineffective. UHD is either limited to the anal ring, or extends 3 - 4 cm into the distal rectum. Over the past 15 years, UHD had in our series an incidence of 13.4 % of all aganglionoses. The gender ratio of girls to boys was 1 : 2.

CONCLUSION: UHD is reliably diagnosed by an AChE reaction in native biopsy sections from the anocutaneous transitional zone and, potentially, from 3 - 4 cm above the pectinate line. As UHD is always accompanied by aganglionosis of the distal internal sphincter, an increase in AChE activity is observed in the nerve fibres of the MCCA. The therapy of choice is a partial myectomy of the distal internal sphincter.