Constipation is commonly defined by the following symptoms: hard stools, painful stools, and stools that are difficult to pass, infrequent, or incomplete, dry, or hardened .
Toward that goal, patients who exhibit alarm signals, or “red flags” (should be evaluated appropriately and should not be considered “functional” until physically and biochemically normal .
A normal child might have a soft stool only every 2nd or 3rd day without difficulty that is not constipation. Constipation can arise from defect in filling or emptying the rectum.
Common cause of constipation includes 1. function constipation 2. Motility disorders 3. Neurological disorders 4. Congenital anomalies 5. Metabolic or endocrine abnormality 6. Drugs .
True constipation in neonatal period most likely secondary to hirschsprung disease , intestinal psudoobstruction , or hypothyroidism .
Colonic stasis leads to ineffective rectal filling and drying of stool and failure to initiate defecation reflex .
Hard , large stool in the rectum become difficult and even painful to evacuate . That’s why more retention occurs and a vicious cycle started . Eventually watery content from the proximal part percolate around hard retained stool and pass per rectum often mistaken as diarrhoea .
To prevent re-accumulation after removing impaction maintenance therapy in the form of dietary modification, toilet training and laxatives needs to be started
immediately after disimpaction or if there is no impaction, then as a first step.
Nelson text book of pediatrics