Acute Abdomen and Peritonitis

Chapter 49 Acute Abdomen and Peritonitis



William E. Charash, MD, PhD , Sarah Pesek, MD




1 What is an acute abdomen?


Any abdominal process that requires urgent (often surgical) intervention. Peritonitis (see question 7) is commonly but not necessarily present. Trauma is generally excluded from discussions of the acute abdomen.



2 What are some causes of acute abdomen that require invasive intervention?




image Perforated hollow viscus (e.g., perforated ulcer, appendicitis, diverticulitis). Perforations that are walled off by the host and not associated with diffuse peritonitis may in certain cases be managed noninvasively.


image Gangrenous hollow viscus, even in the absence of perforation (e.g., mesenteric ischemia, volvulus, complete large bowel obstruction, closed-loop small bowel obstruction, severe acalculous cholecystitis)


image Occlusive mesenteric ischemia, even in the absence of necrosis


image Intraabdominal abscess


image Uncontrolled hemorrhage


image Infected pancreatic necrosis



3 Name some causes of the acute abdomen that are initially treated medically but may ultimately require surgery




image Clostridium difficile colitis (see questions 11-13)


image Abdominal compartment syndrome (see questions 14-17)


image Ogilvie syndrome (see questions 19-20)


image Pancreatitis (see question 28)


image Diverticulitis, small bowel obstruction, inflammatory bowel disease, pelvic inflammatory disease


image Ischemic colitis


image Nonocclusive mesenteric ischemia



4 Which causes of acute abdomen should not require surgery?


Spontaneous bacterial peritonitis (see question 7), gastroenteritis.



5 List thoracic conditions that can cause abdominal pain


Lower lobe pneumonia, pulmonary embolism, pleuritis, empyema, ruptured esophagus, lower rib fractures, pericarditis, and myocardial infarction.



6 How does the initial evaluation of abdominal pain differ in critically ill patients?


The history and physical examination, the mainstay of abdominal evaluation, are often limited because of the patient’s depressed level of consciousness. Nonspecific findings such as unexplained sepsis, hypovolemia, and abdominal distention may suggest an acute abdomen.



7 What is peritonitis?


Inflammation of the peritoneum (visceral and/or parietal). Peritonitis is often accompanied by systemic sepsis. When it occurs spontaneously without any known source of contamination it is termed primary bacterial peritonitis. Secondary bacterial peritonitis originates from visceral pathology or from external sources, such as iatrogenic introduction or penetrating injury.



8 How does peritonitis manifest itself clinically?


As an acute abdomen. Abdominal findings include pain, tenderness, distention, involuntary guarding, or rigidity. Bowel sounds are not typically helpful in this diagnosis but are generally diminished. Other findings are those of systemic infection and may include fever, chills, tachycardia, diaphoresis, tachypnea, oliguria, disorientation, and circulatory collapse. The surface area of the peritoneum is large, roughly the same as the human body (approximately 1.7 m2 for a typical adult). Peritoneal inflammation will generate significant third-space fluid losses and resultant hypovolemia.



9 What laboratory tests are helpful in the setting of abdominal pain?




image A complete blood cell count. An elevated hemoglobin or hematocrit level may suggest third-space fluid losses with hemoconcentration. A low hematocrit may indicate preexisting anemia or active hemorrhage. Elevated white blood cell (WBC) count, especially with left shift, suggests an inflammatory process. A low WBC count may be present if a viral process or gastroenteritis exists, or in the case of overwhelming sepsis.


image Metabolic acidosis on an arterial blood gas level determination, or an elevated lactate level, may indicate an ischemic abdominal process.


image Elevated amylase and/or lipase level may suggest pancreatitis. Amylase may also be elevated with gastric or intestinal pathologic condition.


image Liver function tests may also be helpful.



10 What imaging studies can aid in the diagnosis?




image Oral and intravenous (IV), contrast-enhanced abdominal-pelvic computed tomography (CT) scanning provides the greatest yield. However, this requires a potentially high-risk patient transport. Further, IV contrast might result in contrast-induced nephropathy in a patient already at risk for acute kidney injury. Renal protection with sodium bicarbonate is recommended for high-risk patients.


image Upright (or semiupright) chest radiograph and two-position abdominal radiographs can demonstrate free air (hollow viscus perforation), bowel distention with air, and fluid levels (obstruction).


image Abdominal ultrasound can demonstrate peritoneal fluid collections and acute cholecystitis.


image Angiography or CT-angiography can reveal occlusive vascular disease or active hemorrhage.



11 What causes C. difficile colitis?


Elaboration of toxin A and toxin B by living C. difficile organisms in the colon of the patient. Two conditions are necessary for this to happen. C. difficile, not a component of normal colonic flora, must be iatrogenically introduced into the host. Second, the host’s protective flora must be altered, most typically through the prior use of antibiotics. Both of these factors are within the control of the health care system. Risk factors for severe colitis include age greater than 60 years, residence in a long-term-care facility, gastric acid suppression, severe underlying disease, recent surgery, and immunosuppression.

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Jul 6, 2016 | Posted by in CRITICAL CARE | Comments Off on Acute Abdomen and Peritonitis

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