Laboratory studies are not so important when diagnosing constipation, but there are tests that can be useful like:
- Identifying the levels of thyroid hormones to highlight a potential hypothyroidism.
- Serum electrolytes (Potassium, calcium, Glucose, Creatine)
- Positive hemocult test can spot a tumor cause of intestinal obstruction
- Counting the number of leukocytes for patients with abdominal pain or fever can highlight an ileus
Imagistic studies are necessary to determine the cause of sepsis or the abdominal problems, for patients with acute abdominal pain, fever, leukocytosis or other symptoms that suggest systematic processes or abdominal processes.
Barite enema with contrast
Barite enema with contrast is useful to highlight a volvulus, colonic cancer or a colonic stricture. Patients that don`t have an acute process, the study with gastrografin is more suitable. Gastrografin is better used for patients with acute abdomen because it prevents the risk of Barium extravasate in the peritoneal cavity through a ruptured diverticulum or a colonic cancer.
The colonic preparation starts 8-10 hours before the actual process by drinking a special liquid that cleanse the colon from any matter, usually the night before examination. A Barium solution which is visible on the abdominal radiography, is administrated through the enema of the patient.
Sigmoidoscopy or colonoscopy
Sigmoidoscopy or colonoscopy are the colon examination through a tubular device called endoscope, that lets real time visualization of the existent lesions (injuries) and also, taking biopsies (samples). This is one of the best constipation diagnosis because it gives us real information about the condition of the colon and the detailed view of the intestinal walls.
The method starts with a hydric meal the night before the examination and continuing with a evacuatory cleaning enema before the colonoscopy. The patient is softly sedated before the procedure and a flexible tube is inserted into the colon through the rectum.
The endoscopist will fill the colon with air for a better visualization. During the examination, the patient is laid-down on the bed. After the procedure, the patient can have abdominal distension and flatulent plenitude sensation.
Defecography (evacuation proctography)
Defecography or evacuation proctography is necessary if there is a suspicion of an obstruction at the anal canal level. The procedure consists in filling the rectosigmoidian part with Barium paste and studying the dejection (defecation) by fluoroscopic observation.
The test can demonstrate modifications in the anorectal angle during defecation, the presence of a pelvic platform hypotonicity, rectal prolapse or intussusception. The pressure over the anal sphincter when defecation takes place and the defecation time are other useful investigations with the help of defecography.
Anorectal manometry investigates the extern anal sphincter, the function of the puborectalis muscle, the reflex relaxation of the intern anal sphincter when the rectum is relaxed, the coordination of these muscles in defecation, anorectal pressure.
Electromyography investigates the extern anal sphincter or the puborectal spasms during defecation.
Balloon expulsion is a procedure that consists in inflating a balloon with different quantities of water in the rectum. The patient is asked to eliminate the balloon by defecation. The diminished ability of the elimination of the balloon with 150 ml of water suggests the low defecation ability.
Differential diagnosis examines the abdominal hernia, psychic affections like anxiety, appendicitis, colon cancer, colonic obstruction, ileus, abdominal sepsis, irritable bowel syndrome, toxic megacolon (megalocon toxicum), diverticulitis, hypothyroidism.
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