Alteration in Elimination Part 2

Definition: Constipation is a symptom, not a disease. It reflects an underlying issue in the body.

Fluid Deficit: Lack of sufficient fluids leads to constipation.
Medication Effects:
- Anticholinergics: This class of drugs may lead to constipation by blocking acetylcholine.
- Other drugs that may cause constipation include:
- Diuretics: Pull fluids out of the body, leading to dry stool.
- Opioids: Known to cause constipation as a side effect.
- Calcium-containing Antacids: Can lead to harder stools.
- Iron supplements: Often result in constipation.
Gastrointestinal Disorders: Certain GI conditions or disorders can impair bowel function leading to constipation.
Diet and Lifestyle Factors:
- Inactivity (e.g., long bedrest or hospitalization).
- Insufficient dietary fiber and fluid intake.
- Influence of demographics: Females, older adults, those from non-white ethnic backgrounds, and individuals with low education and income levels are at a higher risk for constipation.

Frequency: Functional constipation is defined as having fewer than three bowel movements a week.
Stool Characteristics: Constipation is defined by the passage of dry, hard feces.
Functional vs. Structural Issues: Bowel function might still be present even at lower frequencies.

Mucosal Dysfunction: Conditions like Hirschsprung's Disease involve the absence of ganglion cells which are essential for bowel relaxation and contraction. The lack of relaxation hampers bowel transit.
Neurophysiological Control: The cerebral cortex regulates defecation, transitioning from involuntary control in infancy to voluntary control. Dysfunction in this area (e.g., spinal cord injury) can lead to constipation.
Psychological Factors: Young populations may ignore the urge to defecate, leading to an aberrant cycle of constipation.
- Example: Adolescents may refuse to use public restrooms due to embarrassment, leading to chronic constipation.

Gastrocolic Reflex: This is a reflex where the stomach signals the colon to empty, facilitating bowel movements after eating.
Increased pressure in the intestine from food leads to a signal promoting defecation.

Dietary Changes: Increase fiber intake to 25-30 grams per day; include prebiotics and probiotics and ensure adequate fluid intake (2-3 liters daily).
Behavioral Therapy: Encouraging movement and regular bathroom visits, particularly post-meal, can enhance bowel movements.

Laxatives vs. Cathartics:
- Laxatives: Produce mild effects, leading to soft stool. Varieties include:
- Bulk-Forming Laxatives: Example: Psyllium (Metamucil) - works by bulking stool to stimulate defecation.
- Lubricant Laxatives: Example: Mineral oil - coats stool to retain moisture and soften.
- Surfactant Laxatives: Example: Docusate - decreases surface tension allowing water to penetrate stool.
- Cathartics: Stronger effects leading to rapid evacuation. Includes stimulant and saline types:
- Stimulant Cathartics: Irritate GI mucosa to promote water retention and accelerated transit; Example: Bisacodyl.
- Saline Cathartics: Example: Polyethylene glycol (PEG) pulls water into the bowel lumen through osmotic action, causing rapid evacuation.

Bulk-Forming Laxatives:
- Examples: Psyllium (Metamucil) - needs to be taken with adequate water to be effective.
- Works by swelling to form a gel that bulks up stool, increasing peristalsis.
- Precaution: Do not use in patients with undiagnosed abdominal pain due to risk of obstruction.
Lubricant Laxatives:
- Example: Mineral oil - prevents water absorption from the stool, keeps it soft.
- Caution: Long-term use can impair absorption of fat-soluble vitamins (A, D, E, K).
Surfactant Laxatives:
- Example: Docusate sodium - softens stool by reducing surface tension, allowing water to enter.
- Primarily used to prevent straining, particularly post-surgical.
Stimulant Cathartics:
- Intuitively indicated for severe constipation; increases intestinal motility.
- Examples: Senna, Bisacodyl - should be used cautiously due to addiction risk.

Lactulose: A disaccharide used not only for constipation but also to manage hepatic encephalopathy by lowering ammonia production and absorption.
Linaclotide: Approved for certain constipation types; contraindicated in pediatrics due to severe adverse reactions.

Definition: Diarrhea is characterized by the frequent passage of liquid stool, typically more than three times a day. Like constipation, it is a symptom of an underlying issue.
- Types: It can present as mild or severe, acute or chronic.
Causes of Diarrhea: Include increased bowel motility, GI infections (E. Coli, rotavirus) or conditions like lactose intolerance.
Symptoms and Risks: Diarrhea can lead to dehydration and electrolyte imbalance, particularly if underlying causes are not addressed.

First 24 hours focus on hydration with clear liquids and gradual reintroduction of a balanced diet, such as a BRAT (Bananas, Rice, Applesauce, Toast) diet to stabilize digestion without excessive irritation.

Anti-Diarrheal Agents:
- Opioid-Related Anti-Diarrheals: Improve symptoms by slowing intestinal motility but bear risks of dependency. Example: Diphenoxylate with atropine.
- Without knowing the cause of diarrhea, using anti-diarrheal agents may not be advisable. They should not be used when infection is suspected as they trap pathogens in the gut.

Frequent assessment of fluid status and electrolyte levels is crucial for patients being treated for either constipation or diarrhea. Monitor for signs of electrolyte imbalances or dehydration as a consequence of pharmacological therapies or dietary changes.