Gastroenterology · Colonic Disorders
The facts most likely to be tested
Diverticulosis is a pseudodiverticulum involving the herniation of mucosa and submucosa through the muscularis propria.
The most common location for diverticulosis in Western populations is the sigmoid colon due to high intraluminal pressure.
Low-fiber diet and chronic constipation are the primary risk factors for the development of diverticula.
Painless hematochezia is the classic clinical presentation of diverticular bleeding, which is the most common cause of lower gastrointestinal bleeding in adults.
Colonoscopy is the diagnostic procedure of choice for evaluating diverticular bleeding once the patient is hemodynamically stable.
Diverticulitis occurs when fecalith obstruction leads to microperforation and subsequent inflammation of the diverticular sac.
CT scan of the abdomen and pelvis with oral and IV contrast is the gold standard diagnostic test for suspected acute diverticulitis.
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A 68-year-old male presents to the emergency department with a large volume of bright red blood per rectum. He reports no abdominal pain, fever, or weight loss. His past medical history is significant for chronic constipation and hypertension. On physical examination, he is hemodynamically stable with a heart rate of 82 bpm and blood pressure of 128/80 mmHg. Abdominal examination reveals no tenderness, guarding, or rebound.
What is the most likely diagnosis and the most appropriate next step in management?
Diverticulosis; Colonoscopy
The patient's presentation of painless hematochezia in the setting of chronic constipation is classic for diverticular bleeding, which is best evaluated via colonoscopy once the patient is stabilized.
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Etiology / Epidemiology
Common in elderly patients with low-fiber diets. Most cases are asymptomatic.
Clinical Manifestations
Usually incidental finding; can cause painless hematochezia (most common cause of lower GI bleed).
Diagnosis
Colonoscopy is the gold standard for visualization. Avoid during acute diverticulitis.
Treatment
High-fiber diet and hydration are first-line. Avoid seeds/nuts is a myth.
Prognosis
Most remain asymptomatic; 10-25% develop diverticulitis.
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Epidemiology & Etiology
Prevalence increases with age, affecting >50% of individuals over age 80. Primary risk factors include low-fiber intake, chronic constipation, and obesity. It is most common in the sigmoid colon due to high intraluminal pressure.
Pertinent Anatomy
Diverticula are pseudodiverticula, involving only the mucosa and submucosa herniating through the muscularis propria. These herniations occur at weak points where the vasa recta penetrate the circular muscle layer.
Pathophysiology
Chronic constipation leads to increased intraluminal pressure, causing focal weakness in the colonic wall. This results in the formation of sac-like protrusions. While usually asymptomatic, the vasa recta can become thinned and rupture, leading to significant painless lower GI bleeding.
Clinical Manifestations
Most patients are asymptomatic. When symptomatic, the hallmark is painless hematochezia, which is often self-limiting. Red flags include hemodynamic instability, persistent tachycardia, or signs of peritonitis, which suggest progression to diverticulitis or other pathology.
Diagnosis
The colonoscopy is the gold standard for diagnosis and ruling out malignancy. Avoid colonoscopy during acute diverticulitis due to the risk of perforation. If active bleeding is present, angiography or tagged RBC scan may be required for localization.
Treatment
Management focuses on prevention of progression via a high-fiber diet and adequate fluid intake. Avoid seeds, nuts, and popcorn is no longer recommended as evidence does not support this restriction. For acute bleeding, initial management is resuscitation with IV fluids and blood products if necessary.
Prognosis
The majority of patients remain asymptomatic throughout their lives. Complications include diverticulitis (inflammation/infection) and diverticular hemorrhage. Patients should be monitored for signs of infection or persistent bleeding.
Differential Diagnosis
Diverticulitis: presence of fever, leukocytosis, and localized abdominal pain
Angiodysplasia: painless bleeding, typically right-sided, common in elderly
Colorectal cancer: weight loss, change in bowel habits, iron deficiency anemia
Ischemic colitis: crampy abdominal pain followed by bloody diarrhea, often post-hypotension
Hemorrhoids: bright red blood per rectum, typically associated with defecation