What is the best course of action for an elderly female patient with hematochezia, painful defecation, and no bowel movement, considering the possibility of colorectal cancer and other diagnoses?

Immediate Management of Elderly Female with Hematochezia and Painful Defecation

This elderly patient requires urgent colonoscopy within 24 hours after initial stabilization, as hematochezia in an elderly patient carries a high risk of colorectal malignancy and the inability to defecate with pain suggests possible obstruction or advanced rectal pathology. 1

Initial Assessment and Stabilization

Immediate Clinical Evaluation

• Perform a careful digital rectal examination to assess for rectal mass, impaction, anal fissure, or perianal pathology that could explain both the bleeding and painful defecation 1
• Observe the perianal area for prolapsed hemorrhoids, thrombosed external hemorrhoids, or visible rectal mass 1
• Check vital signs immediately for tachycardia, hypotension, or signs of hypovolemic shock, as severe hematochezia can cause hemodynamic instability 1
• Assess for peritoneal signs that would indicate perforation or ischemia 1

Essential Laboratory Testing

• Obtain complete blood count to assess for anemia and hemoglobin drop 1, 2
• Check coagulation profile, renal function, electrolytes, and lactate level 1
• Elevated lactate or marked leukocytosis suggests intestinal ischemia or perforation 1

Initial Supportive Management

• Start intravenous crystalloid resuscitation immediately with isotonic fluids 1
• Insert Foley catheter to monitor urine output 1
• Consider nasogastric tube placement if there is concern for upper GI source or bowel obstruction 1
• Maintain hemoglobin >7 g/dL with blood transfusion if necessary 1

Diagnostic Approach

Urgent Colonoscopy Indication

Colonoscopy is mandated in this patient and should be performed urgently within 24 hours for the following reasons:

• Hematochezia in elderly patients confers a hazard ratio of 10.66 for colorectal cancer, with 38% being rectal cancers 1
• The combination of rectal bleeding with inability to defecate raises concern for obstructing rectal or sigmoid mass 1
• Colonoscopy must be complete to the cecum to exclude proximal lesions 1
• Age >50 years is an absolute indication for full colonoscopy with hematochezia 1, 3

Critical Differential Diagnoses to Consider

Colorectal Cancer (Most Likely)

• Accounts for 60% of large bowel obstruction in adults 1
• Hematochezia with painful defecation and obstipation is classic for obstructing rectal or sigmoid cancer 1
• Do not delay colonoscopy as delays are associated with more advanced disease 2

Severe Hemorrhoidal Disease

• Can cause significant bleeding but typically allows passage of stool 1
• Less likely to cause complete inability to defecate 1

Rectal Ulcer or Ischemia

• Severe pain with attempted defecation suggests mucosal pathology 1
• Ischemic colitis more common in elderly with vascular disease 1

Fecal Impaction with Stercoral Ulceration

• Can cause both obstipation and bleeding 4
• Digital rectal exam should identify this 1

Management Algorithm

If Hemodynamically Stable

1. Perform digital rectal examination and anoscopy to identify anorectal pathology 1
2. Proceed with urgent colonoscopy within 24 hours after adequate bowel preparation if feasible 1
3. If colonoscopy reveals obstructing mass, obtain tissue diagnosis and surgical consultation immediately 1

If Hemodynamically Unstable or Signs of Perforation

1. Resuscitate aggressively with crystalloids and blood products to maintain MAP >65 mmHg 1
2. Obtain urgent CT abdomen/pelvis to assess for perforation, obstruction, or ischemia 1
3. Emergent surgical consultation for possible operative intervention 1
4. Colonoscopy deferred until stabilized 1

If Upper GI Source Suspected

• Perform upper endoscopy as up to 15% of patients with severe hematochezia have upper GI bleeding 1
• Feculent gastric aspirate on nasogastric suction suggests distal small bowel or colonic obstruction 1

Critical Pitfalls to Avoid

Do Not Attribute Bleeding to Hemorrhoids Without Colonoscopy

• Even if hemorrhoids are present on examination, colonoscopy is still mandatory in elderly patients to exclude synchronous malignancy 1, 3
• Hemorrhoids and cancer can coexist 5, 4

Do Not Use Fecal Immunochemical Testing (FIT) in Symptomatic Patients

• FIT is for screening asymptomatic patients, not for diagnostic evaluation of hematochezia 1
• Colonoscopy is the only appropriate test for this presentation 1

Do Not Perform Only Flexible Sigmoidoscopy

• Although most pathology may be distal, complete colonoscopy to cecum is required to exclude proximal lesions 1, 3
• Up to 9.9% of young patients with hematochezia have proximal adenomas 5

Do Not Delay Evaluation

• Colonoscopy should be performed within 30 days maximum for alarm symptoms, but urgently within 24 hours for ongoing bleeding 2
• This patient's presentation warrants urgent evaluation given age, bleeding, and obstructive symptoms 1