How do medical professionals diagnose elimination disorders?
A complete evaluation of a child with constipation or encopresis involves a thorough history, a detailed physical examination, and may include laboratory testing. The child's pediatrician may generally handle the analysis of these elements. A pediatric GI specialist consultation may be indicated should a more ominous cause for the elimination disorder be discovered or if the evaluation produces conflicting data and thus obscures the establishment of the exact cause and thus management for the child's problem.
The history to be explored during an evaluation of elimination disorders includes: (1) age and abruptness of onset, (2) frequency and character of the current stool pattern in comparison to that noted prior to the onset of symptoms, (3) relationship to ingestion of meals as well as types of food in the child's diet, (4) unusual weight loss or gain, (5) associated abdominal complaints (for example, abdominal pain), (6) urological issues (many children with elimination disorders may also have enuresis -- involuntary loss of bladder control), (7) psychosocial family dynamics (for example, parental/sibling/peer response to the problem), and (8) gentle exploration for any possibility of sexual abuse -- regression, depression, sexually acting out, etc.
The goal of a complete physical exam is to eliminate the possibility of anatomical or functional causes for the elimination disorder. Children affected by cerebral palsy, global hyponia (low muscle tone), mental retardation, and anatomical malformations (for example, spinal cord abnormalities or displacement of the anus) must be considered and ruled out as a cause for the child's symptoms. Physical examination of the abdomen will often demonstrate a large stool mass. A rectal exam will commonly demonstrate an enlarged rectal volume that is packed with stool. Absence of anal muscular tone should be a "red flag" for a potential neurological disorder. As noted above, appropriate anal location should be documented. Likewise, the physician should perform an evaluation for hidden spinal cord malformations (for example, tuft of hair over the lower spine).
Most children with either constipation or encopresis do not need laboratory or radiographic evaluation unless the history and/or physical examination warrant further analysis (for example, an MRI for spinal cord malformations). Blood studies to evaluate thyroid function may be a consideration on an individualized basis. An abdominal X-ray may be helpful to measure the child's stool burden. For those children with urologic problems, a culture and urinalysis are reasonable studies. A pediatric gastroenterologist may perform a study of anal and rectal muscle tone (anal/rectal manometry) to assess the anal/rectal response to inflation with air in children who do not respond to routine therapy.