A 38-year-old man who recently returned from visiting his family in the Philippines presents to the emergency department with 1 week of fatigue, low-grade fever, abdominal pain, and jaundice. Laboratory results include:
Serology comes back as:
The serology results are most consistent with which of the following?
Correct Answer: C
The presence of the combination of anti-HBs and anti-HBc IgG with all other hepatitis B markers being negative suggests immunity from a prior infection. Hepatitis B surface antigen (HBsAg) is a marker of current infection. Hepatitis B surface antibody (anti-HBs) is a marker of immunity through vaccination or previous exposure. Hepatitis B core antibody IgG (anti-HBc IgG) is a marker of previous exposure. Hepatitis B core antibody IgM (anti-HBc IgM) is generally a marker of acute HBV infection, although it can also be positive during spontaneous exacerbation of chronic HBV.
A 68-year-old woman has been in the ICU for 5 days receiving ceftazidime for Pseudomonas aeruginosa meningitis following surgical removal of a meningioma. This morning on rounds her nurse mentions that the patient had three loose stools overnight. Laboratory results show that the patient’s white blood cell count jumped from 7,600 to 16,500 cells/µL. Serum creatinine has also increased from 1.2 to 1.9 mg/dL. Nucleic acid amplification test and stool toxin test are both positive for Clostridium difficile.
What is the recommended management?
Correct Answer: B
All antibiotics, including vancomycin and metronidazole, carry a risk for C. difficile infection (CDI); however, clindamycin, ampicillin, cephalosporins, and fluoroquinolones are associated with the majority of infections. Patients with three or more new, unexplained loose stools in 24 hours should be tested for CDI. All patients with suspected CDI should be placed on contact precautions pending test results and, if positive, these precautions should be continued for at least 48 hours after diarrhea has resolved. Nucleic acid amplification testing, either alone or as part of an algorithm including initial enzyme immunoassay screening for glutamate dehydrogenase antigen and toxins A and B, is now the preferred diagnostic test. Vancomycin or fidaxomicin PO are the recommended antibiotics for the initial episode of both severe and nonsevere disease; however, metronidazole can be used for nonsevere disease if access to oral vancomycin or fidaxomicin is limited. This patient has severe disease based on a leukocytosis of >15,000 cells/µL and serum creatinine >1.5 mg/dL. Repeat testing following resolution of diarrhea is not indicated because >50% of patients will continue to harbor both the organism and toxin.
A 45-year-old man with a history of alcoholic cirrhosis and poor medication compliance is dropped off in the emergency department by a friend. He is:
On examination he is sleepy but rouses to voice. He cannot remember how he got to the hospital and gets irritated with repeated questions. He has asterixis and hyperactive reflexes. His abdomen is moderately distended but not tense or painful. In addition to admitting the patient and starting medical management of his decompensated cirrhosis, what is the best approach to working up and treating a possible infection?
Correct Answer: D
All inpatients with ascites should have a diagnostic paracentesis performed at least once during every admission, and it should be repeated if the patient develops new evidence of infection during their stay. The symptoms of spontaneous bacterial peritonitis (SBP) can be subtle, and sending ascitic fluid for culture is a cost-effective way to detect an unexpected infection. The prevalence of SBP in hospitalized patients with cirrhosis and ascites is ∼10%. Initial laboratory testing should include ascitic fluid cell count and differential, ascitic fluid total protein, serumascites albumin gradient (SAAG), and both aerobic and anaerobic cultures. Cultures should be obtained before the initiation of antibiotics. Other tests may also be indicated based on the clinical scenario. In the presence of cirrhosis a SAAG of >1.1 g/dL nearly always indicates that the ascites is from portal hypertension. Patients with an ascitic protein concentration of <15 g/L have an increased risk of SBP. An ascitic fluid polymorphonuclear (PMN) leukocyte count greater than 250 cells/mm3 suggests the presence of infection, even if cultures are negative, and empiric antibiotics should be started. Patients with an ascitic fluid PMN count less than 250 cells/mm3 , but with signs and symptoms of infection, should also receive empiric antibiotic coverage. Gram stain cannot rule out infection because the concentration of bacteria in the ascitic fluid is often very low (ascitic fluid cultures are positive only ∼40% of the time in patients with other clinical evidence of SBP). The most common organisms cultured are Escherichia coli, Klebsiella pneumoniae, and Streptococcal pneumoniae. The preferred treatment for community-acquired SBP is cefotaxime or a similar thirdgeneration cephalosporin. For patients with nosocomial SBP or recent betalactam antibiotic exposure, empiric antibiotics should be based on local antibiograms.
A previously healthy 63-year-old woman presents to the emergency department with 24 hours of severe abdominal pain, nausea, and vomiting. Vital signs include:
On examination, she is in moderate distress with diffuse epigastric pain and diminished bowel sounds. Laboratory results include:
Correct Answer: A
The diagnosis of acute pancreatitis (AP) can be made when patients meet two of the following three criteria: abdominal pain consistent with pancreatitis (constant, generally severe epigastric or left upper quadrant pain that may radiate to the back, chest, or flank), serum amylase or lipase greater than three times the upper limit of normal, and/or characteristic findings on imaging. Serum lipase level is the laboratory test of choice. The American Society for Clinical Pathology even chose testing lipase instead of amylase in cases of suspected AP as one of its recommendations for the Choosing Wisely initiative. ICU admission criteria should be the same as with other patients, but ICU or step-down admission should also be considered for patients who are at high risk of deterioration, such as those at risk of severe AP. Patient characteristics that increase the risk of developing severe AP include age >55 years, BMI >30 kg/m2 , altered mental status, and presence of comorbid disease. No specific laboratory or imaging results have been able to reliably predict severity in AP, so close monitoring for hypovolemic shock and evidence of organ dysfunction are important. Other risk factors for severe AP include the presence of systemic inflammatory response syndrome, evidence of hypovolemia (elevated BUN or creatinine, hemoconcentration), pleural effusions or pulmonary infiltrates, and presence of multiple or extensive extrapancreatic fluid collections. Death within the first week is usually due to progressive organ dysfunction. Routine use of prophylactic antibiotics is not recommended, even in the presence of severe disease, unless there is evidence of extrapancreatic infection. All patients should receive an abdominal ultrasound to evaluate for cholelithiasis, which is the most common cause of AP (40%-70% of cases). Patients with mild AP can begin eating a low-fat diet as soon as tolerated. Patients with severe AP should be started on enteral nutrition to prevent infectious complications. Parenteral nutrition should only be used if the enteral route is not available, not tolerated, or not meeting caloric requirements.
A previously healthy 24-year-old man presents to the emergency department with severe right lower quadrant pain, anorexia, and nausea. Vital signs include:
Physical examination is significant for exquisite right lower quadrant tenderness with rebound and guarding. Laboratory test results reveal a white blood cell count of 19,000 cells/µL with a left shift. CT with contrast shows appendiceal wall thickening, periappendiceal fat stranding, and a focal defect in the enhancing wall of the appendix.
In addition to IV fluids, what are the next best steps in management?
This patient’s clinical picture is consistent with perforated appendicitis. Even in the absence of imaging findings, the positive peritoneal signs, hypotension, significantly elevated temperature, and high white blood cell count point to a serious intra-abdominal infection that requires exploration. In the setting of imaging consistent with acute appendicitis, five sensitive and specific CT findings for perforated appendicitis include abscess, phlegmon, extraluminal air, extraluminal appendicolith, and focal defect in the enhancing appendiceal wall. A focal defect in the appendiceal wall is the most sensitive finding. However, up to half of patients with perforated appendicitis will have imaging consistent with simple appendicitis, so imaging by itself cannot rule out perforation.
An intravenous fluid bolus is indicated to treat the patient’s hypotension. Because this patient is otherwise healthy and presenting from home, he is not considered to be at an increased risk for resistant or hospital-associated organisms. Coverage of narrower gram-negative and obligate anaerobic organisms is adequate despite the severity of the infection. Recommended single agents include ertapenem and moxifloxacin. Combination regimens could include cefotaxime or ceftriaxone plus metronidazole or ciprofloxacin plus metronidazole. No more than 4 days of antibiotic therapy is recommended for patients with perforated appendicitis who undergo surgery and have adequate source control. Although antibiotics alone have been shown to be successful in simple inflamed appendicitis, 25% to 30% of patients will require readmission or surgery within 1 year. Appendectomy is still recommended for most patients presenting with appendicitis. Patients such as this one with sepsis or peritonitis due to acute appendicitis require urgent surgery. Timing of appendectomy in mild to moderate cases of appendicitis has been more controversial, but delays of 12 to 24 hours have not been associated with increased rates of complications such as perforation.
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