Professor of Radiology, Paediatric Radiologist. Department of Radiology, Maastricht University Medical Centre, Maastricht, The Netherlands
Defecation disorders are common in children causing abdominal complaints in the children and anxiety of the parents. A large spectrum of disorders may cause constipation at different ages. In newborns it includes anatomical anomalies (i.e. anorectal malformations), Hirschsprung’s disease, meconium ileus and meconium plug syndrome. Anorectal malformations will be discussed in the abstract of a separate lecture. Hirschsprung’s disease is caused by an absence of ganglion cells resulting in abnormal motility and lack of relaxation (figure). The length of the aganglionic segment is variable but always the distal end of the intestinal tract is affected. In a small number of patients the entire colon, and even the ileum and jejunum are involved. US is of limited value because of the air-artefacts in dilated bowel loops. However in very early neonatal US air is not yet present and distension of the colon in a neonate with distal occlusion suggests Hirschsprung’s disease. Sometimes a necrotizing enterocolitis cause stenosis of the colon that may mimic Hirschsprung’s disease and initial US examination may suggest the proper diagnosis. Meconium plug syndrome can be considered as neonatal obstipation and has a good prognosis whereas meconium ileus is a severe disease, virtually always caused by cystic fibrosis. These neonatal obstructions need immediate diagnosis and treatment to avoid complications. Ultrasonography and large bowel contrast enemas are the modalities of choice to make the diagnosis. In older children functional disorders and neurological disorders are frequent causes of constipation and can be diagnosed by the paediatrician. Patients that do no respond well to therapy will proceed to diagnostic imaging such as abdominal X-rays (to quantify the amount of stools in the colon), ultrasonography (to estimate the amount of stools in the rectum thereby avoiding rectal digital examination) and finally contrast enema and/or defaecography (to rule out Hirschsprung’s disease or anatomical malformations).