Chronic constipation - the role of clinical assessment and colorectal physiologic tests to obtain an etiologic diagnosis

BACKGROUND: Diagnosis of subtypes of chronic constipation has been considered difficult to achieve even in specialized centers. Although colorectal physiologic tests have brought an important contribution, it remains unclear in which patients these tests should be indicated for. AIMS: This study aims to establish a differential diagnosis for chronic constipation cases using clinical assessment and physiologic tests and to identify clinical parameters that could predict which patients need physiologic tests. METHODS: One hundred and seventy nine patients (83% females; mean age, 45) with chronic constipation according to Rome II criteria were initially treated by dietary advice and functional reeducation and those unresponsive (110 or 61.5%) were submitted to colonic transit time, defecography, anorectal manometry and electromyography, as needed. RESULTS: A differential diagnosis was achieved in 63.6% of patients tested. However, 61.5% of 179 patients with chronic constipation (69 with no need to tests and 40 with normal tests) have etiologic diagnosis established only on clinical basis. Irritable bowel syndrome (32%), pelvic floor dysfunction (29%) and functional constipation due to faulty diet and life style habits (22%) were the main causes of chronic constipation. Alternating constipation and nausea/vomiting were symptoms significantly related to the diagnosis of irritable bowel syndrome; younger age, larger intervals between bowel movements, occurrence of fecal impaction and necessity of enema were related to the diagnosis of non-chagasic megacolon and digital assistance to evacuate and large rectocele or spastic pelvic floor on rectal exam were associated to pelvic floor dysfunction. Patients with long-standing constipation, fecal impaction, abdominal pain not eased after defecation, necessity for enemas, digital assistance and evidence of rectocele tended to be in need for physiologic tests to define the cause of chronic constipation. CONCLUSIONS: The etiologic diagnosis of chronic constipation can be achieved in most of patients on a clinical basis and some symptoms may be significantly related to specific diagnoses. Indications for physiologic tests should be based on specific clinical parameters.