The North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) and the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) endeavored to formulate uniform evidence-based guidelines for evaluation and management of functional constipation in 2014.19 Despite the unreliability and non-specificity of symptom description in infants and young children, history and physical examination is still the main basis of the diagnosis.
History and physical examination
The main points to be noted are age of onset, defecation frequency, consistency of stools (expressed in some scale like Bristol scale, Lane’s modified Bristol stool form scale or Amsterdam infant stool scale), status of toilet training, pain during defecation, blood in stools, Constipation associated Fecal Incontinence (CFI), retentive posturing, diet history, weight loss and nausea/vomiting.20–22 Age of onset prior to one month suggests strong probability of Hirschprung’s disease.23 Time of passing first meconium also needs to be enquired as a lag of >48 hours strongly favors diagnosis of Hirschsprung’s disease.24 Many times there would be a precipitating factor for constipation such as an episode of painful defecation, changeover of feeds from breastfeeding to formula feeding or commencement of toilet training, etc.25 Likewise, dietary history, treatment history, developmental history and psychosocial history are also important. Family history of gastrointestinal disorders (Hirschsprung’s disease, inflammatory bowel disease, celiac disease, food allergies, etc) and disorders of other organs like thyroid, parathyroid, kidneys or other conditions like cystic fibrosis should be enquired.
Physical examination should include 19
· Anthropometry to evaluate growth
· Abdominal examination (palpable fecal mass, abdominal distension)
· Lumbosacral area ( sacral dimple, tuft of hair, gluteal cleft deviation, sacral agenesis, flat buttocks)
· Perianal inspection ( perianal fissures or skin tags, location of anal opening, stool in the anus or inner clothing)
· Anal wink reflex and cremasteric reflex
· Digital rectal examination (anal stenosis, fecal mass). Explosive stools after removal of finger suggests Hirschsprung’s disease
· Neuromuscular examination: Tone, power, deep tendon reflexes
Digital rectal examination (DRE) in diagnosis of constipation
When history and abdominal examination does not accurately identify diagnosis of constipation, DRE can be used. Beckman et al did a study to determine the accuracy of clinical variables to diagnose radiographically established constipation.26 Taking colon filled with fecal material to radiographically define constipation, it was found that stool present in rectal exam was the best variable that distinguishes between patients with and without constipation. If there are no palpable abdominal fecoliths and no history of CFI, DRE would be required to detect “fecal mass in the rectum” which is one of the criteria for ROME III definition of constipation.3,4 The NASPGHAN and ESPGHAN 2014 guideline recommends DRE for diagnosis of constipation if only 1 out of 6 criteria in Rome III is satisfied and discourages routine use of DRE to diagnose constipation.19
Though functional constipation is the most common cause of constipation, other differential diagnoses should be considered and should be ruled out in history and examination. The following alarm signs and symptoms would help to identify presence of an organic disease causing constipation 6,19
· Passage of meconium after 48 hours of birth
· Constipation starting very early in life (<1 month) · Ribbon stools · Family history of Hirschsprung's disease · Failure to thrive · Blood in stools in the absence of anal fissures · Fever · Abnormal position of anus · Bilious vomiting · Absent cremasteric/anal reflex · Sacral dimple · Tuft of hair on spine · Decreased strength/ tone/reflex in lower extremities · Anal scars · Extreme fear during anal inspection · Deviation of gluteal cleft In presence of any of the above mentioned alarm signs or in case constipation is not responding to usual treatment further workup is necessary to rule out organic causes of constipation. The following differential diagnosis should be considered 19 · Hirschprung's disease · Hypothyroidism · Celiac disease · Electrolyte abnormalities (Hypercalcaemia, hypokalemia) · Dietary protein allergy · Diabetes mellitus · Toxins/drugs Ø Opiates, anticholinergics Ø Chemotherapy Ø Antidepressants Ø Heavy metal ingestion (e.g. lead) · Botulism · Spinal cord anomalies, trauma, tethered cord · Anatomic malformations Ø Imperforate anus Ø Anal stenosis · Vitamin D intoxication · Cystic fibrosis · Anal achalasia · Pelvic mass (e.g. sacral teratoma) · Colonic inertia · Abnormal abdominal musculature ( prune belly, gastroschisis, Down syndrome) · Multiple endocrine neoplasia type 2B · Pseudo-obstruction (visceral neuropathies, myopathies, mesenchymopathies)