What K66 covers · when clinicians use it
ICD-10 code K66 identifies Other disorders of peritoneum in the U.S. ICD-10-CM clinical and billing record set. It sits within the Digestive System chapter (K00–K95), the section that groups related diagnoses so providers, payers, and public-health agencies report them consistently. Clinicians and medical coders apply K66 when an encounter's findings match the Other disorders of peritoneum description, attaching it to the patient record so downstream insurance claims, payer audits, quality reporting, and epidemiological surveillance all reference the same standardized diagnosis. The ICD-10-CM is maintained by the Centers for Medicare & Medicaid Services and the CDC's National Center for Health Statistics, with an updated official code set released each U.S. fiscal year — always verify K66 against the current CMS/CDC release and your payer's documentation guidance before final use. This page summarizes documentation context for K66 and is a coding reference, not clinical, diagnostic, or billing advice.
K66 refers to Other disorders of peritoneum, a group of conditions affecting the peritoneum (the lining of the abdominal cavity) or retroperitoneal space. These disorders can be life-threatening and often present as surgical emergencies requiring rapid diagnosis and treatment.
Symptoms
- Severe abdominal pain – Especially diffuse or rebound tenderness in peritonitis (K65)
- Fever and chills – Indicate underlying infection or inflammation
- Abdominal distension – Common with retroperitoneal or peritoneal pathology
- Nausea and vomiting – Often present in acute peritoneal conditions
- Signs of sepsis – Hypotension, tachycardia, and confusion in severe cases
Diagnosis
Diagnosis of Other disorders of peritoneum is made through clinical examination, peritoneal fluid analysis, blood cultures, abdominal ultrasound, CT scan, or exploratory surgery. Prompt diagnosis is essential to prevent systemic spread of infection or complications.
ICD10 Code Usage
ICD10 code K66 is used by emergency physicians, surgeons, and radiologists. It supports documentation for surgical intervention (e.g., laparotomy), antibiotic treatment, and critical care coding in hospitals or urgent care settings.
Related Codes
- K65 – Peritonitis
- K67 – Disorders of peritoneum in infectious diseases classified elsewhere
- K68 – Disorders of retroperitoneum
FAQs
Q1: What is ICD10 code K66?
A: It refers to Other disorders of peritoneum, involving acute or chronic inflammation or disorders of the peritoneal or retroperitoneal spaces.
Q2: Is peritonitis (K65) always infectious?
A: Most often yes, but it can also result from chemical irritation (e.g., bile, gastric contents) or secondary to organ rupture.
Q3: What is included under K66?
A: K66 includes adhesions, encapsulating peritoneal sclerosis, or spontaneous hemoperitoneum not due to trauma.
Q4: How is K67 different?
A: K67 is used when peritoneal disorders are secondary to infections like tuberculosis or systemic sepsis already classified elsewhere.
Q5: Who treats these conditions?
A: General and trauma surgeons, critical care specialists, infectious disease experts, and radiologists.
Conclusion
ICD10 code K66 ensures proper classification and care planning for Other disorders of peritoneum, helping guide emergent surgical decisions, infection control measures, and accurate clinical reporting.