K57

Diverticular disease of intestine

Diverticulitis is a clinical condition characterized by the inflammation and/or infection of diverticula, which are small, herniated sacs of the mucosal and submucosal layers that protrude through the muscularis propria of the intestinal wall. While the presence of these sacs is termed diverticulosis, their acute inflammation constitutes diverticulitis. The pathophysiology typically involves the erosion of the diverticular wall due to increased intraluminal pressure or the presence of a fecalith (inspissated fecal matter), leading to inflammation, focal necrosis, and micro-perforation. Clinically, the condition is categorized as uncomplicated (localized inflammation) or complicated (associated with abscess, fistula, bowel obstruction, or macro-perforation with peritonitis). It most frequently involves the sigmoid colon in Western populations, although right-sided diverticulitis is increasingly recognized. Diagnosis is predominantly confirmed via Computed Tomography (CT) imaging showing colonic wall thickening and pericolic fat stranding.

Clinical Symptoms

  • Acute, persistent abdominal pain typically localized in the lower left quadrant (LLQ)
  • Fever and chills
  • Localized abdominal tenderness, guarding, or rebound tenderness
  • Leukocytosis (elevated white blood cell count)
  • Nausea and vomiting
  • Change in bowel habits, most frequently constipation or, less commonly, diarrhea
  • Abdominal bloating and flatulence
  • Palpable abdominal mass (in cases of abscess formation)
  • Dysuria or urinary frequency (due to bladder irritation from adjacent colonic inflammation)
  • Signs of systemic sepsis in severe, perforated cases

Common Causes

  • Formation of colonic diverticula due to high intraluminal pressure and wall weakness
  • Obstruction of the diverticular neck by a fecalith or undigested food particles
  • Low-fiber dietary patterns leading to smaller stool volume and increased straining
  • Obesity and high Body Mass Index (BMI), particularly central adiposity
  • Sedentary lifestyle and lack of regular physical activity
  • Chronic use of nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, or opioid analgesics
  • Smoking and tobacco use
  • Genetic predisposition and structural integrity variations in the intestinal wall
  • Alterations in the gut microbiome (dysbiosis) and mucosal immune system dysfunction

Documentation & Coding Tips

Distinguish between diverticulosis and diverticulitis to ensure proper category selection.

Example: Patient with known diverticulosis of the sigmoid colon presents with acute left lower quadrant pain, leukocytosis, and fever. CT scan confirms acute sigmoid diverticulitis without evidence of perforation or abscess. Plan: Start oral ciprofloxacin and metronidazole.

Billing Focus: Documentation of diverticulitis allows for higher level of medical decision making compared to diverticulosis.

Explicitly state the presence or absence of hemorrhage to capture specific fourth or fifth character codes.

Example: 65-year-old male with diverticulitis of the large intestine with hemorrhage. Patient presents with bright red blood per rectum and severe abdominal pain. Hemoglobin dropped from 14.2 to 10.1. Urgent gastroenterology consultation requested for colonoscopy.

Billing Focus: Codes such as K57.21 or K57.31 are used specifically when bleeding is documented, leading to higher complexity and resource utilization.

Document the anatomical location, specifically small intestine versus large intestine or both.

Example: Intraoperative findings during laparotomy reveal diverticulitis of the small intestine with perforation and localized peritonitis. Sigmoid colon and remainder of large intestine appear normal. Segmental resection of the affected jejunum performed.

Billing Focus: Laterality and site specificity prevent claim denials due to lack of specificity in the ICD-10 block K57.

Identify complications such as perforation, abscess, or peritonitis to support codes in the K57.0, K57.2, K57.4, or K57.8 series.

Example: Chronic diverticulitis of the large intestine with perforation and pericolic abscess. CT abdomen shows a 4cm rim-enhancing fluid collection adjacent to the sigmoid colon with extraluminal air. Interventional Radiology consulted for percutaneous drainage.

Billing Focus: The presence of an abscess or perforation moves the code from the simple diverticulitis category to the complicated diverticulitis category.

Clarify if the condition is acute, chronic, or acute on chronic to reflect the clinical status accurately.

Example: Patient has a history of recurrent diverticular disease. Currently presenting with an acute on chronic diverticulitis of the large intestine without perforation or hemorrhage. Patient reports similar symptoms three times in the last 18 months.

Billing Focus: Accurate description of chronicity supports the medical necessity for surgical interventions like elective colectomy.

Document specific findings like fistulas (colovesical, colovaginal) associated with the diverticular disease.

Example: Diverticulitis of the sigmoid colon with colovesical fistula. Patient reports pneumaturia and fecaluria. Cystogram confirms communication between the sigmoid colon and the bladder dome.

Billing Focus: Fistula documentation requires additional specificity and often links to higher-level surgical CPT codes.

Relevant CPT Codes

Related Diagnoses

Hierarchy