Learn about the symptoms, causes, treatment options, and prevention of peritonitis. Learn how to diagnose this serious abdominal condition.
Table of Contents
- What is peritonitis? Definition and types
- Most common causes of peritonitis
- Symptoms of peritonitis – what to pay attention to?
- Diagnosing peritonitis – necessary tests
- Modern methods of peritonitis treatment
- Prevention and possible complications of peritonitis
What is peritonitis? Definition and types
Peritonitis (Latin: peritonitis) is a serious inflammatory condition affecting the peritoneum – a thin, semi-permeable serous membrane that lines the abdominal cavity and surrounds the organs within it. The peritoneum acts as a protective barrier against the spread of infection within the abdomen; it also participates in substance absorption and the production of serous fluid, which allows for free movement of visceral organs. When this integral structure is disrupted, for example by organ perforation, trauma, or the presence of microorganisms, inflammation can develop, triggering a rapid immune defense response. In clinical practice, peritonitis is considered one of the most dangerous acute abdominal conditions, requiring immediate diagnosis and intensive treatment.
Peritonitis is classified into two main groups: primary (spontaneous) and secondary. Primary peritonitis develops without any identifiable local cause in the abdomen, most often as a result of microorganisms traveling via the bloodstream (bacteremia) or by continuity from pelvic organs (especially in women) and is relatively rare. Typical cases of primary peritonitis occur in children with nephrotic syndrome, patients with liver cirrhosis, or those undergoing peritoneal dialysis—in this group, bacterial infections such as Escherichia coli, Streptococcus pneumoniae, and Enterococcus predominate. Secondary peritonitis is much more common and is related to the direct entry of microorganisms, digestive enzymes, bile, or intestinal contents into the peritoneal cavity, most often as a result of gastrointestinal tract wall perforation in the course of diseases such as appendicitis, peptic ulcer disease of the stomach or duodenum, colon perforation, Meckel’s diverticulum rupture, postoperative or post-traumatic complications, or organ puncture due to trauma. Secondary peritonitis is characterized by the involvement of a mixture of microorganisms, both aerobic and anaerobic, which significantly complicates the course of the disease and requires comprehensive treatment. There is also a third category – tertiary peritonitis, which accompanies chronic and recurrent infections, most often in individuals with significant chronic comorbidities or after prolonged hospitalization, often caused by microbes with increased resistance to treatment and fungi. Within the aforementioned types, it is also important to distinguish between generalized peritonitis, which affects all or most of the peritoneum – significantly worsening the prognosis, and limited local forms—encapsulated inflammations such as peri-appendiceal or perihepatic abscesses, where the inflammatory process is confined by neighboring organs or anatomical structures. It should not be forgotten that the course and severity of peritonitis can vary dramatically depending on the cause, type of infection, speed of pathological process development, presence of accompanying illnesses, and the patient’s immune status. For this reason, accurate identification of the type and location of peritonitis is crucial for implementing an appropriate therapeutic strategy and preventing serious complications, such as sepsis, multi-organ failure, or shock.
Most common causes of peritonitis
Peritonitis can be caused by a variety of factors, but the most common include gastrointestinal tract perforations and bacterial infections within the abdominal cavity. The most frequently encountered form is secondary peritonitis, developing as microorganisms or other irritant substances penetrate the peritoneal cavity. One of the main causes is the perforation of abdominal organs, especially the appendix (acute appendicitis leading to rupture), gastric or duodenal ulcer (whose perforation spills stomach or intestinal contents into the peritoneum), or bowel obstruction leading to rupture of the intestinal wall. Other less common but equally dangerous causes include colon perforations due to diverticulosis, Crohn’s disease or ulcerative colitis. Peritonitis can also develop as a result of tissue necrosis, postoperative complications, or abdominal trauma, both open and closed. Surgical procedures, such as resection of internal organs, sometimes carry the risk of peritoneal damage and introduction of microorganisms into the abdominal cavity, creating favorable conditions for the development of a severe infection. The second group includes primary peritonitis, which develops without an explicit local abdominal cause. It mainly affects people with weakened immune defenses, chronic liver diseases, especially advanced cirrhosis, when ascitic fluid accumulates in the abdomen. In such cases, the defensive mechanisms of the peritoneum are impaired, and microorganisms, most often Gram-negative bacteria (e.g. Escherichia coli), can penetrate into the abdomen through the intestinal wall or via the bloodstream and cause inflammation. In children, primary peritonitis may be associated with nephrotic syndrome, where hypoalbuminemia promotes infection. Tertiary peritonitis should also be mentioned, mainly affecting patients with prolonged hospitalization, chronic antibiotic therapy, or weakened immunity. Here, the infection recurs despite previous treatment, often caused by antibiotic-resistant or atypical pathogens such as fungi or multi-resistant bacterial strains.
Other less obvious but equally important causes of peritonitis include infections of pelvic organs, particularly in women of reproductive age. Inflammation of the adnexa (ovaries and fallopian tubes) and postpartum complications may be a source of infection spreading to the peritoneum. A similar route of infection can occur in bladder perforation or acute cholecystitis, especially if rupture occurs. In dialysis patients, especially those undergoing peritoneal dialysis, the risk of peritonitis is clearly increased – the source of infection is often improper technique or equipment contamination. Several cases also occur when bacteria enter the peritoneum via the bloodstream, for example in the course of a systemic bacterial infection such as sepsis, or, less commonly, as a complication of tuberculous peritonitis. In every case of developing peritonitis, it is extremely important to quickly identify the primary cause, as this is essential for selecting an appropriate treatment and minimizing the risk of complications. Often, symptoms suggesting peritonitis appear suddenly and are alarming in nature, thus detailed diagnostic evaluation is necessary to determine the source of infection. In clinical practice, most cases involve infections of intestinal origin, especially associated with gastrointestinal wall disruption, but complications after surgery, pelvic organ or dialysis infections, and chronic diseases weakening the immune system are equally dangerous. Understanding the mechanisms and factors that lead to peritonitis allows for the implementation of preventive measures and faster recognition of alarming symptoms to initiate effective therapy.
Symptoms of peritonitis – what to pay attention to?
Peritonitis is characterized by a set of symptoms of varying severity, which may develop rapidly or build gradually depending on the cause and extent of inflammation. The most characteristic and common symptom is severe, sudden abdominal pain that often appears unexpectedly and tends to escalate quickly. The pain is usually diffuse, involving the whole abdomen or worsening in a specific region, especially if the cause is localized, e.g., in the case of appendiceal perforation. As peritonitis progresses, pain transitions into what is called a “board-like” abdomen – permanent, strong abdominal muscle tension leading to rock hard abdomen, reflecting a reflexive muscular defense against the spreading inflammation. Often, the patient will try to remain motionless, minimize breathing movements, bend their legs, or lay on one side, as movement exacerbates the pain. Additional symptoms may include gastrointestinal complaints such as nausea, persistent vomiting, loss of appetite, and increased thirst, often leading to dehydration. There is commonly arrest of passing gas and stool, and in extreme cases—signs of paralytic ileus, causing complete gastrointestinal inertia. When generalized infection develops, local symptoms can give way to systemic failure manifestations, such as tachycardia, rapid breathing, weakness, excessive sweating, and blood pressure drop, sometimes progressing to septic shock. It’s also important to note the appearance of high fever, in some cases with chills, although complete absence of fever does not rule out the inflammatory process – particularly in the elderly or immunocompromised, the febrile response may be weak or absent. One of the clearest alarm signs requiring urgent medical consultation is impaired consciousness, delirium, attention disturbances, and sudden deterioration of overall health.
The clinical picture of peritonitis includes several symptoms which can be observed during medical examination and self-observation. On abdominal palpation, muscular defense is evident – the patient shows strong resistance and pain with any touch of the abdominal wall, and the doctor may detect generalized or localized tenderness, or characteristic peritoneal symptoms such as a positive Blumberg sign (pain intensifies with sudden withdrawal of hand from the abdomen) or the cough sign (pain increases during coughing). Frequently, there is also tachycardia, shallow and rapid breathing, and signs of dehydration visible as dry tongue, sunken eyeballs, decreased skin turgor, or reduced urine output. Another worrisome signal is the development of systemic intoxication symptoms due to bacterial toxins. Particular care should be taken with patients with comorbidities (e.g., chronic renal failure, diabetes, liver cirrhosis), as their symptoms may be atypical, mild, or masked by underlying disease. In children, the elderly, and immunocompromised patients, peritonitis often presents with less specific symptoms, such as apathy, no desire to eat, general malaise, or orientation disturbances, which further complicates proper assessment. Also note that the presence of a peritoneal dialysis catheter or history of abdominal surgeries increases the risk, and the onset of symptoms in such groups requires prompt medical action. Peritonitis symptoms are dangerous and can rapidly lead to complications, making quick recognition in oneself or those close essential, as well as prompt medical intervention. Laboratory and imaging test results are also an integral part of diagnosing peritonitis and, in combination with described symptoms, enable accurate diagnosis and life-saving treatment.
Diagnosing peritonitis – necessary tests
Diagnosis of peritonitis requires a comprehensive, multi-stage approach that allows not only confirmation of inflammation in the abdominal cavity, but also identification of its cause and assessment of disease severity. The diagnostic process begins with a detailed medical interview and physical examination, which play a key role in recognizing peritonitis. The doctor pays attention to symptoms such as sudden, severe abdominal pain, lack of bowel sounds, abdominal firmness and tension (the so-called board-like abdomen), and peritoneal signs during palpation. If this serious complication is suspected, risk factors for infection such as previous surgeries, peritoneal dialysis, chronic diseases, or prior gastrointestinal perforations are evaluated. In addition to clinical examination, a broad range of laboratory tests is required. Most commonly, a complete blood count with differential, C-reactive protein (CRP), procalcitonin and ESR are performed as markers of systemic inflammation. White blood cell count (leukocytosis) and electrolyte disturbances from vomiting and dehydration are typical. Patients with extensive peritonitis may have impaired renal and liver function, acid-base disturbances, and features of developing sepsis; hence blood gas analysis and liver and kidney enzyme panels are also often performed. In those on peritoneal dialysis, dialysate fluid is analyzed—cloudiness and increased cell count suggest infection.
Imaging studies play a crucial role in confirming the diagnosis and localizing the source of inflammation. The first-line test is abdominal ultrasound (USG), useful for detecting free fluid—especially in the pelvis and perienteric spaces—identifying gastrointestinal perforations, abscesses, or inflammatory changes in parenchymal organs. When USG results are ambiguous or complications are suspected, an abdominal computed tomography (CT) scan with contrast is performed—this test is much more precise, allowing identification of the cause (e.g., perforation, abscess, trauma) and assessing the extent of inflammatory process. In some cases, an upright abdominal X-ray may be useful for detecting free air under the diaphragm, a typical sign of gastrointestinal perforation. When imaging is inconclusive, or symptoms are becoming more severe, diagnostic laparoscopy can be used, allowing direct assessment of the peritoneum and abdominal organs, sampling for microbiological testing, and therapeutic interventions. Material from peritoneal fluid or abscess swabs is sent for bacteriology with antibiogram and evaluation for fungi or other atypical pathogens, thus facilitating targeted antibiotic therapy. In sum, diagnosing peritonitis concerns identifying the inflammatory process itself, its etiology, severity, and systemic complications. In special cases, such as immunocompromised patients or those with chronic organ diseases, additional serological and immunological tests may be needed. It is crucial to remember that treatment effectiveness is highly dependent on diagnostic speed and accuracy, thus every suspected case of peritonitis requires immediate, multi-step, interdisciplinary evaluation to enable the best therapeutic strategy.
Modern methods of peritonitis treatment
Modern medicine provides patients with peritonitis effective, individualized therapeutic options, the choice of which depends on disease stage, cause, and the patient’s overall condition. The basis of treatment remains rapid stabilization with intensive monitoring of vital functions—especially fluid-electrolyte balance, proper hydration, and support of the heart and kidneys. For most patients, treatment begins with the immediate introduction of broad-spectrum intravenous antibiotics, targeting Gram-negative, Gram-positive, and potential anaerobic microorganisms. Given increasing bacterial resistance to standard antibiotics, modern treatment often uses new-generation drugs and rapid microbiology tests, enabling quick adjustment of therapy according to antibiogram results. Identifying the infection source is crucial: peritonitis caused by organ perforation (e.g., stomach, intestinal wall, gallbladder) requires urgent surgical intervention to eliminate the focus and prevent the spread of bacteria in the abdomen. Modern surgery uses advanced minimally invasive techniques such as laparoscopy, which allows not only rapid identification of the source but also effective peritoneal lavage and closure of the perforation, resulting in lower complication risk, shorter hospital stay, and quicker recovery. Where the clinical situation requires broader action, classic open surgery (laparotomy) is performed, including the resection of diseased segments or drainage of abscess zones.
In addition to classic surgical methods and antibiotics, supporting procedures are of growing importance—such as intensive anticoagulant care, modern immunomodulatory drugs, and individually tailored nutritional strategies. Current treatment protocols focus on early enteral or parenteral nutrition, which is essential in prolonged gastrointestinal failure and improves recovery outcomes and reduces metabolic complications. In advanced inflammation, advanced peritoneal lavage techniques with specialized solutions and modern drainage forms—including vacuum-assisted closure (VAC) systems—are used to effectively limit infection spread and improve healing. Vital-signs monitoring in intensive care is vital in severe cases, as advanced peritonitis requires strict supervision of the heart, kidneys, respiratory system, and supporting therapies such as dialysis, hemofiltration, or high-flow respiratory techniques (e.g. non-invasive ventilation). Modern laboratory and imaging diagnostics enable rapid detection of complications (intra-abdominal abscesses, organ failure, multiple organ dysfunction syndrome—MODS), ensuring immediate targeted therapy. Supportive therapies (e.g., gut microbiome aids or immunomodulating treatments), especially in immune-deficient or chronically ill or post-major surgery patients, are increasingly used. Advances in medicine have made peritonitis treatment a complex, interdisciplinary process, demanding collaboration between surgeons, anesthesiologists, microbiologists, pharmacologists, and clinical dietitians, aiming not only to save lives but also to minimize long-term consequences and improve post-illness quality of life.
Prevention and possible complications of peritonitis
Effective prevention of peritonitis is based on reducing risk factors and rapid response to symptoms indicating threats to the integrity of the digestive tract or other abdominal organs. The most important elements include early identification and treatment of diseases that may lead to organ perforation, such as appendicitis, ulcerative colitis, peptic ulcer disease, or gastrointestinal cancers. Regular check-ups for those with chronic liver conditions such as cirrhosis allow for early detection of ascites and introduction of primary peritonitis prevention with appropriate antibiotics (for patients with high risk of spontaneous bacterial peritonitis). For peritoneal dialysis patients, sterilization and education on proper technique and strict monitoring of catheter sites is crucial, as any technical error or carelessness can result in a rapidly progressing infection. Rapid treatment of urinary tract or pelvic infections, regular imaging tests post-surgery, and eliminating immune-lowering factors—such as lifestyle modifications, proper diet, and avoiding stimulants—are also important. Wide-ranging health education and increased awareness of symptoms requiring immediate medical intervention are key, especially in high-risk groups like the elderly, immunocompromised, or chronically ill. Preventive action at every stage of medical care can significantly reduce the number and severity of peritonitis cases.
Despite advances in peritonitis diagnosis and treatment, the disease carries a number of serious complications, largely depending on duration, cause, and the patient’s general condition. The most dangerous and life-threatening complications are systemic, such as sepsis and resultant multi-organ failure, most often affecting the cardiovascular, respiratory, kidney, and liver systems. The key to reducing these risks lies in quick diagnosis and immediate treatment, as delays can lead to septic shock, electrolyte disorders, deep dehydration, and metabolic acidosis. Common local complications include intra-abdominal abscesses, intestinal fistulas, peritoneal adhesions, or secondary gastrointestinal failure, leading to chronic pain, recurrent infections, and bowel obstruction requiring surgery. Patients after severe, widespread peritonitis are also at risk for long-term hospital complications—secondary nosocomial infections, thrombosis, as well as nutrition disorders and weight loss, which can delay recovery and worsen prognosis. Complications of surgical treatment, such as bleeding, wound infection, or thromboembolic incidents, are also relevant. Some patients, especially those with comorbidities, may develop chronic pain syndromes and permanent impairment of gastrointestinal function, requiring months of treatment or reoperation. In peritoneal dialysis patients, there is a risk of permanent peritoneal damage, limiting ongoing dialysis and leading to fibrosing inflammation. Effective complication prevention demands multidisciplinary care, accurate diagnosis, and early therapeutic and rehabilitation intervention. Close attention should be paid to vital monitoring, regular follow-ups, and cooperation between patient and medical team throughout treatment and convalescence.
Summary
Peritonitis is a serious, life-threatening condition, so rapid recognition of the symptoms and prompt treatment are crucial. Being aware of the most common causes and early warning signs such as severe abdominal pain or bloating helps avoid complications. Diagnosis is based on clinical and imaging assessment, while effective treatment often requires surgical intervention and antibiotics. Prevention and proper management of other abdominal diseases can significantly reduce the risk of peritonitis. Quick response and specialized medical care are key to patient health and life.
