Peritonitis: A High-Stakes Diagnosis LNCs Must Understand

Christopher Grey, a 62-year-old man, arrives at the emergency department with worsening abdominal pain, fever, and nausea.

His chart shows he was seen two days earlier at the ED. He gave a history of falling off a ladder and landing face down. “Yes, I have some pain in my abdomen”, he said when asked. Despite this history, no abdominal studies were done. Christopher was discharged with a diagnosis of “gastroenteritis.”

Now, he is hypotensive, confused, and in severe distress. Imaging reveals a perforated bowel with widespread infection in the abdominal cavity. Despite aggressive treatment, Christopher develops septic shock and dies.

This scenario illustrates how quickly peritonitis can progress—and how devastating the consequences can be when diagnosis or treatment is delayed. For LNCs, understanding peritonitis is key when reviewing cases involving abdominal pain, surgical complications, or sepsis.

What Is Peritonitis?

Peritonitis is inflammation of the peritoneum, the thin tissue lining the inner wall of the abdomen and covering abdominal organs. It is most often caused by infection—either bacterial or fungal—and is considered a medical emergency.

Peritonitis is broadly categorized into two types:

• Primary (spontaneous) peritonitis: Typically occurs in patients with liver disease and ascites, without an obvious source of contamination.
• Secondary peritonitis: Results from a breach in the gastrointestinal tract or abdominal organs, allowing bacteria to enter the sterile peritoneal cavity.

Common Causes of Peritonitis

The most frequent causes of secondary peritonitis include:

• Perforated bowel (from conditions such as diverticulitis, ulcers, or trauma, as in the case of Christopher)
• Appendicitis with rupture
• Postoperative complications, including anastomotic leaks
• Pancreatitis leading to inflammation and infection
• Abdominal trauma, including penetrating injuries
• Dialysis-related infections, particularly in peritoneal dialysis patients

In many cases, the underlying issue begins as a localized condition that becomes life-threatening once contamination spreads.

Signs and Symptoms

Peritonitis often presents with symptoms that should prompt urgent evaluation:

• Severe abdominal pain, often diffuse and worsening
• Abdominal tenderness with guarding or rigidity
• Fever and chills
• Nausea and vomiting
• Decreased bowel sounds
• Tachycardia and hypotension in advanced cases

A key clinical feature is rebound tenderness, indicating irritation of the peritoneum. As the condition progresses, patients may develop signs of sepsis, including altered mental status and organ dysfunction.

Mortality and Outcomes

Peritonitis carries a significant risk of death, especially when diagnosis or treatment is delayed. Mortality rates vary widely depending on the cause, patient condition, and timeliness of intervention:

• Secondary peritonitis: Mortality rates range from 10% to over 30%
• Severe cases with septic shock: Mortality can exceed 50%
• Elderly or immunocompromised patients: Higher risk of poor outcomes

The most important factor influencing survival is time to diagnosis and treatment. Delays in recognizing a perforation, ordering imaging, initiating antibiotics, or consulting a surgeon can have fatal consequences.

How the Legal Nurse Consultant Analyzes These Cases

Christopher Grey’s wife’s attorney contacts her LNC to get her involved in reviewing this case. When reviewing medical records involving peritonitis, the LNC plays a pivotal role in identifying whether the standard of care was met. Although AI software can organize the medical records, pull out duplicates, and create a start to finish chronology, your knowledge as an LNC is critical.

Focus areas include:

1. Timeline of Symptoms and Care
   Establish when symptoms began and how they evolved. Analysis of an AI-generated chronology helps with this step. Was abdominal pain documented clearly? Your analysis takes over for the rest of this evaluation of the medical records. Look to see if worsening signs were recognized. Did providers respond appropriately to changes?

2. Assessment and Documentation
   Evaluate the thoroughness of physical examinations. Was abdominal tenderness described? Were red flags such as guarding or rebound tenderness noted?
3. Diagnostic Testing
   Review whether appropriate imaging (such as CT scans) and laboratory tests were ordered in a timely manner. Delays in imaging are a common issue in missed or delayed diagnoses.
4. Clinical Decision-Making
   Examine whether providers considered serious causes of abdominal pain. Was the patient prematurely discharged? Were alternative diagnoses ruled out adequately?
5. Treatment Interventions
   Assess the timing of antibiotics, fluid resuscitation, and surgical consultation. In cases of perforation, surgeons’ prompt surgical intervention is often key.
6. Communication and Handoffs
   Look for breakdowns in communication between providers, especially during transitions of care. Critical information may be lost or minimized. Using a calendar for that month and year, determine if a holiday or weekend was the timing of care.

By organizing these elements into a clear timeline, the LNC helps the attorney see where care met expectations—and where it may have fallen short.

Educating the Attorney

Most attorneys are not clinically trained and may not immediately grasp the urgency or complexity of peritonitis. The LNC’s ability to explain this condition clearly can shape case strategy.

Effective approaches include:

Use plain language explanations
Instead of medical jargon, describe peritonitis as “a serious infection inside the abdomen caused by leakage from an organ.” This helps attorneys understand the stakes quickly.

Highlight cause-and-effect relationships
Explain how a delay—such as failing to order imaging—can allow infection to spread, leading to sepsis or death.

Create visual timelines
A chronological summary showing symptom progression, provider actions, and missed opportunities can be highly persuasive.

Focus on decision points
Identify moments where different choices could have changed the outcome. For example: “At this evaluation, the patient had worsening pain and fever, which should have triggered further evaluation.”

Connect medical facts to legal issues
Clarify how deviations from standard care may relate to liability, causation, and damages.

Final Thoughts

Peritonitis cases often hinge on timing, recognition, and response. For legal nurse consultants, these cases offer an opportunity to bring clarity to complex medical events and help attorneys understand where care may have gone wrong.

When you can clearly explain how a localized problem turned into a life-threatening emergency—and whether that progression was preventable—you provide insight that can influence the direction of a case.

Join us when gastroenterologist and expert witness Stephen Cohen shares tips on evaluating cases involving abdominal catastrophes. He’ll speak at the April 23, 24 and 25, 2026 LNC Success (R) Online conference. Meet Dr. Cohen in the video below.

Register here.

Pat Iyer MSN RN LNCC is president of The Pat Iyer Group. She develops resources to assist LNCs in obtaining more clients, making more money, and achieving their business goals and dreams.

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