Adult Hirschsprung disease

Clinical History

A 28-year-old man presented with complaints of chronic severe constipation since childhood.

Imaging Findings

A 28-year-old man presented with complaints of chronic severe constipation since childhood. He complained of progressive abdominal pain and increasing abdominal distension for the last 5 weeks. He had last passed stool about 10 days back. Clinical examination revealed a distended firm abdomen. CT scan of abdomen revealed a markedly dilated sigmoid and descending colon containing abundant faecal matter. The dilated colon demonstrated an abrupt but smooth transition at the recto-sigmoid junction. The rectum was collapsed and appeared normal in calibre. Peri-rectal fat planes appeared normal. No obvious intraluminal bowel pathology was seen. Diagnostic possibility of aganglionic colon was considered. Barium enema demonstrated similar findings and was followed by a full thickness rectal biopsy. Histopathology confirmed aganglionosis (Hirschsprung disease).

Discussion

Hirschsprung disease (HD) was named after Harald Hirschsprung, the Danish physician who first described this entity in 1886. Hirschsprung disease is a congenital defect characterised by the absence of enteric neurons of the rectum and/or colon. It affects about 1 out of 5,000 infant and is more common in males than in females, with a male-to-female ratio of 4:1. Almost all cases of HD are diagnosed within 2 years after birth; out of which almost 50% are diagnosed in infancy. Only a meagre percentage of HD is diagnosed much later in childhood. The typical presentation is of delayed passage of meconium in a neonate or history of chronic constipation since birth in an older child. Other clinical manifestations include abdominal distention, poor feeding, poor weight gain, failure to thrive, and bowel obstruction with bilious vomiting. HD constitutes one-third of all cases of neonatal bowel obstruction. Clinical examination can reveal a distended abdomen and palpable faeces filled dilated colonic loops. A per-rectal examination often reveals an empty rectal vault and can result in the forceful expulsion of faecal matter upon completion of examination. Up to 5-15% of children with HD may have trisomy-21. Other associated anomalies include cardiac defects, genitourinary abnormalities, and gastrointestinal anomalies such as colonic atresia and imperforate anus. The aetiopathogenesis of HD includes absence of the ganglion cells of the myenteric and submucosal (Auerbach and Meissner) plexus resulting in a narrowed aganglionic segment of colon. This results in upstream dilatation of the normally innervated proximal colon. The transition zone from an abnormal aganglionic to a normal ganglionic bowel is located at the rectosigmoid or sigmoid colon in 65% of patients, the descending colon in 14%, the rectum in 8%, and the more proximal large bowel in 10% of patients.

Adult HD is definitely a rare occurrence with limited case reports especially pertaining to their imaging findings. Adult patients typically present with a life-long or chronic history of constipation. Large faecalomas can cause additional symptoms such as bowel ulceration, bleeding or perforation. Imaging plays an important role in evaluation of these patients. Detailed medical history along with barium enema examination and/or CT-imaging is vital for confirming the clinical suspicion and ruling out other conditions. A full-thickness rectal biopsy is considered diagnostic. Plain radiograph of abdomen can show massive colonic distension with intraluminal inspissated faeces. Single-contrast barium enema is the most popular investigation for delineating the transitional zone which is seen as a cone-shaped or funnel-shaped area of narrowing. Affected spastic segment may demonstrate a sawtooth configuration due to muscular contractions. The recto-sigmoid calibre ratio gets reversed (less than-1) owing to a reduced rectal distensibility. Secondary to the functional obstruction, the unaffected proximal colon gets massively dilated. It may show large intraluminal filling defects (faecalomas). Cross sectional imaging such as CT plays an important role in excluding other relatively more common causes of chronic constipation in adults including colonic carcinoma. The limited radiological literature available has shown consistent results between the transition zone depicted on CT and histopathological reports.

Differential Diagnosis List

Final Diagnosis

Adult Hirschsprung's disease

URL:	https://www.eurorad.org/case/8715
DOI:	10.1594/EURORAD/CASE.8715
ISSN:	1563-4086