Constipation

Functional Causes

Idiopathic constipation: Common in the general population, often due to dietary factors (low fiber intake), dehydration, or lack of physical activity
Irritable bowel syndrome (IBS): Characterized by abdominal pain, bloating, and altered bowel habits, including constipation (IBS-C)
Slow transit constipation: Reduced colonic motility, often seen in young women, leading to infrequent bowel movements and hard stools
Pelvic floor dysfunction: Difficulty in stool evacuation due to dyssynergic defecation, often seen in women post-pregnancy
Psychosocial factors: Stress, anxiety, and depression can contribute to functional constipation

Obstructive Causes

Colorectal cancer: Constipation, often accompanied by rectal bleeding, unexplained weight loss, and iron deficiency anemia, especially in older adults
Strictures: Narrowing of the bowel lumen due to inflammatory bowel disease, previous surgery, or radiation therapy, leading to obstructive symptoms
Anal fissures: Painful defecation leading to voluntary stool withholding, resulting in hard stools and worsening constipation
Rectocele: Herniation of the rectal wall into the vagina, causing obstructive symptoms during defecation, common in multiparous women
Intestinal obstruction: Can be partial or complete, presents with constipation, abdominal pain, distension, and vomiting

Metabolic and Endocrine Causes

Hypothyroidism: Slowed metabolism leading to constipation, weight gain, cold intolerance, and dry skin
Hypercalcemia: Associated with constipation, polyuria, polydipsia, abdominal pain, and confusion, often due to hyperparathyroidism or malignancy
Diabetes mellitus: Autonomic neuropathy can lead to gastroparesis and constipation, often associated with poor glycemic control
Hypokalemia: Electrolyte imbalance leading to muscle weakness, cramps, and constipation, often secondary to diuretic use or gastrointestinal losses
Pregnancy: Hormonal changes (increased progesterone) slow gastrointestinal motility, leading to constipation

Drug-Induced Causes

Opioids: Common cause of constipation due to reduced gastrointestinal motility, often requiring laxatives for management
Anticholinergics: Drugs like tricyclic antidepressants and antihistamines can cause constipation by reducing bowel motility
Calcium channel blockers: Medications like verapamil can cause constipation by affecting smooth muscle contraction in the gut
Iron supplements: Frequently cause constipation, especially when taken in high doses
Diuretics: Can lead to constipation due to dehydration and electrolyte imbalances
Antipsychotics: Medications like clozapine can cause significant constipation and ileus due to their anticholinergic effects

Onset and Duration

Acute vs chronic: Acute onset may suggest an obstructive cause, while chronic constipation is often functional or related to lifestyle factors
Frequency and consistency: Changes in bowel habits, stool consistency (using Bristol Stool Chart), and frequency are important to identify the pattern of constipation
Associated symptoms: Presence of pain, bleeding, weight loss, or systemic symptoms such as fatigue may indicate a more serious underlying cause
Lifestyle factors: Dietary habits, fluid intake, and physical activity level can contribute to functional constipation
Evacuation difficulties: Difficulty with stool passage, sensation of incomplete evacuation, or use of manual maneuvers may suggest pelvic floor dysfunction or rectal abnormalities

Background

Past medical history: History of bowel disorders (e.g., IBS, inflammatory bowel disease), surgeries, or conditions like diabetes, hypothyroidism, or Parkinson’s disease can predispose to constipation
Drug history: Use of medications known to cause constipation, recent changes in medication, or over-the-counter laxative use
Family history: Family history of colorectal cancer, polyps, or hereditary bowel disorders may increase suspicion of a genetic predisposition
Social history: Dietary habits, alcohol use, smoking, and occupational factors such as sedentary lifestyle are relevant
Psychosocial factors: Stress, anxiety, or depression may exacerbate or contribute to functional constipation
Bowel habits: Details about regularity, consistency, and any previous episodes of constipation or changes in bowel routine

Bedside Tests

Abdominal examination: To assess for distension, masses, tenderness, or signs of fecal loading
Rectal examination: To check for rectal masses, anal fissures, hemorrhoids, or impacted stool
Bristol Stool Chart: To classify stool consistency and correlate with patient symptoms
Vital signs: To assess for systemic signs of dehydration, infection, or metabolic disturbances
Urinalysis: To exclude urinary tract infection or dehydration, which can exacerbate constipation

Blood Tests

Full blood count: To assess for anemia (which may indicate colorectal cancer) and signs of infection
Urea and electrolytes: To check for dehydration, electrolyte imbalances such as hypokalemia or hypercalcemia
Thyroid function tests: To exclude hypothyroidism as a cause of constipation
Calcium levels: To check for hypercalcemia, which can cause constipation
Glucose levels: To check for diabetes, particularly if autonomic neuropathy is suspected
CRP/ESR: To assess for inflammation, particularly if inflammatory bowel disease or another inflammatory process is suspected

Imaging and Special Tests

Abdominal X-ray: To assess for fecal loading, dilated bowel loops suggesting obstruction, or free air if perforation is suspected
Colonoscopy or flexible sigmoidoscopy: Indicated if there are red flag symptoms such as rectal bleeding, weight loss, or anemia to rule out colorectal cancer or other pathology
Barium enema: Rarely used but can be helpful in diagnosing conditions like volvulus, strictures, or Hirschsprung’s disease
Defecography: Specialized imaging to assess for pelvic floor dysfunction, rectocele, or intussusception
Transit studies: To measure colonic transit time in cases of suspected slow transit constipation
Anorectal manometry: To assess anal sphincter function and coordination in cases of suspected pelvic floor dysfunction

Gastrointestinal