Elimination

Fecal Elimination: Physiology and Characteristics of Defecation

  • Definition of Defecation: The process of eliminating waste (feces or stool) from the digestive system.
  • Physiological Stimulus: Feces cause distention of the rectum, which stimulates distention receptors to trigger the urge for defecation.
  • Positioning: The sitting position is optimal as it increases downward pressure on the rectum, facilitating the passage of stool.
  • Normal Stool Characteristics:     * Color: Brown (Adult); Yellow (Infant).     * Consistency: Formed, soft, semisolid, moist.     * Shape: Cylindrical (following the contour of the rectum), approximately 2.5 cm2.5\text{ cm} (1 in1\text{ in}) in diameter for adults.     * Amount: Varies with diet, typically 100−400 g/day100-400\text{ g/day}.     * Odor: Aromatic; influenced by ingested food and the individual's bacterial flora.     * Constituents: Small amounts of roughage, dead bacteria, epithelial cells, fat, protein, and dried digestive juices (bile pigments/inorganic matter).
  • Abnormal Stool Characteristics and Possible Causes:     * Clay or White: Absence of bile pigment (bile obstruction) or diagnostic studies using barium.     * Black or Tarry: Iron medications; upper gastrointestinal (GI) bleeding (stomach/small intestine); diet high in red meat and dark green vegetables (e.g., spinach).     * Red: Lower GI bleeding (rectum); foods like beets; hemorrhoids; Coumadin (medication); cancer.     * Pale/Orange/Green: Malabsorption of fats; diet high in milk/low in meat; intestinal infection.     * Hard/Dry: Dehydration; decreased motility; lack of fiber/exercise; laxative abuse.     * Narrow/Pencil-shaped: Obstructive conditions of the rectum.     * Pungent Odor: Infection or presence of blood.     * Constituents: Pus, parasites, mucus (bacterial/inflammatory conditions), large quantities of fat (malabsorption), or foreign objects.

Factors Affecting Bowel Elimination

  • Developmental Stages: Newborns and infants; toddlers; school-age children and adolescents; older adults.
  • Dietary Fiber:     * Soluble Fiber: Dissolves in water to form a gel-like material. Found in oats, peas, beans, apples, citrus fruits, and barley.     * Insoluble Fiber: Promotes movement through the system and increases stool bulk. Found in wheat flour, wheat bran, nuts, and vegetables.
  • Other Factors: Physical activity, psychological stress, defecation habits, medications (laxatives), diagnostic procedures, anesthesia/surgery, pathological conditions, and pain.

Alterations in Bowel Elimination

  • Constipation: Defined as fewer than three bowel movements per week. Stools are hard, dry, and formed.     * Causes: Low fiber/fluid intake, immobility, irregular habits, lack of privacy, chronic laxative/enema use, IBS, pelvic floor dysfunction, neurologic conditions (Parkinson's, stroke), and medications (opioids, iron, antihistamines, antacids, antidepressants).
  • Fecal Impaction: A collection of hardened feces in the rectal folds. Symptoms include the passage of liquid fecal seepage with no normal stool.     * Causes: Poor habits, anticholinergics/antihistamines, and residual barium after radiologic exams.     * Treatment: Oil retention enema followed by a cleansing enema 2−4 hours2-4\text{ hours} later; daily stool softeners or suppositories.
  • Diarrhea: Passage of liquid feces and increased frequency (more than 3 times/day3\text{ times/day}) associated with abdominal pain and hyperactive bowel sounds.     * Clostridium difficile (C. Diff): Produces mucoid, foul-smelling diarrhea. Common in immunosuppressed patients