A 55-year-old male is brought to the intensive care unit (ICU) after an exploratory laparotomy because of a motor vehicle collision where he suffered a liver laceration. He is intubated with an open abdomen and a negative pressure abdominal wound dressing. He remains hypotensive on norepinephrine infusion of 1 µg/kg/min and was transfused 16 units of packed RBCs, 8 units of fresh frozen plasma, 8 packs of platelets, 2 bags of cryoprecipitate. Repeat laboratory tests show a stable hemoglobin postoperatively. However, his urine output starts to decline, and his pressor requirements start to rise. On examination, the abdomen is distended and tight. In the case of intra-abdominal hypertension (IAH), what is the minimum ideal abdominal perfusion pressure (APP) correlating to improved survival?
Correct Answer: D
Patients with an open abdomen and a negative pressure wound dressing can still develop IAH and abdominal compartment syndrome (ACS). Intraabdominal pressure (IAP) of 5 to 7 mm Hg is considered a normal steady state pressure within the abdominal space. Morbidly obese patients may have a higher baseline IAP. APP is calculated as the mean arterial pressure minus the IAP. Studies have showed that an APP of at least 60 mm Hg is correlated with improved survival from IAH and ACS. This resuscitation end point was found to be more important than arterial pH, base deficit, lactate, and hourly urine output in regression model analysis. IAH is defined as IAP greater than or equal to 12 mm Hg. There are four grades of IAH. ACS is defined as IAP greater than or equal to 20 mm Hg with signs of end organ dysfunction. The standard method of measuring IAP is measurement of bladder pressures. Care must be taken to make these measurements with consistent head and body positioning, ideally with a paralyzed patient at end expiration.
A 48-year-old male who is 1 month status postorthotopic liver transplant for NASH Cirrhosis is transferred to the ICU with abdominal distention, pain, and septic shock. He has a known history of duodenal ulcer. A computed tomography (CT) of the abdomen and pelvis does not show any obvious free air or perforation. Sepsis guidelines are followed, and the decision is to proceed with a diagnostic paracentesis. The fluid drained does not contain any bile staining.
Which one of the answers below supports a spontaneous bacterial peritonitis rather than a secondary bacterial peritonitis?
Correct Answer: A
When there is a clinical concern for the diagnosis of primary versus secondary bacterial peritonitis, cell counts and cultures often do not help to differentiate. In these diagnostic dilemmas examination of fluid chemistries may help with the diagnosis. Although when the serum-ascites albumin gradient (SAAG) is greater than 1.1 g/dL is highly suggestive of portal hypertension with 97% accuracy, it does not help differentiate between primary versus secondary bacterial peritonitis alone. Measure of the ascites fluid total protein concentration can often provide additional diagnostic clues. Patients with the most “dilute” ascites have the lowest level of opsonins, which puts them at the highest risk of spontaneous bacterial peritonitis. Ascites fluid protein concentration less than 1 g/dL correlates inversely with higher risk of developing spontaneous bacterial peritonitis. Additionally, neutrophils consume large amounts of glucose and thus ascites glucose concentration generally remains above 50 mg/dL in spontaneous bacterial peritonitis. But this number often falls below this level in secondary bacterial peritonitis, which can help with the diagnosis. In bowel perforations, the levels may fall to as low as zero. Ascites fluid lactate dehydrogenase (LDH) in the ascites fluid is released when the PMNs have been lysed. The LDH numbers rise in spontaneous bacterial peritonitis, but their numbers increase even further in secondary bacterial peritonitis. The upper limit varies but LDH levels in sterile ascites generally range between 40 ± 20 units/L. Amylase levels are elevated in the ascites fluid with pancreatitis and bowel perforation supporting a secondary bacterial peritonitis.
An 85-year-old male who was recently treated for an upper respiratory tract infection presented 2 days ago with abdominal pain. On abdominal examination, he has tenderness to palpation with mild distention but no signs of peritonitis. On admission, the WBC was 25 cell/mL and now it is 18 cell/mL. Urinalysis does show bacteria and the initial diagnosis is a UTI. Cultures have been sent. Chest X-ray does not show any evidence of pneumonia. He starts to develop hypotension on the floor with oliguria requiring 2 L of crystalloid. A request is made to transfer the patient to the ICU. The nurse notes that in the past 24 hours, he has had four episodes of diarrhea. Stool was sent for GDH (glutamate dehydrogenase) and Toxin A and B. GDH was negative, but the Toxin A/B was positive. She asked the intern on the floor to start IV Flagyl for a presumed Clostridium difficile infection, but the intern has not started it yet. Aside from the sepsis guidelines and ICU care, what is the NEXT step to address a possible C. difficile infection?
Correct Answer: C
The laboratory approaches to diagnosis of C. difficile is followed when there is a suspicion for C. difficile infection. Generally, this infection is suspected when there is acute onset, and clinically significant diarrhea (≥ three loose stools over 24 hours) and risk factures such as recent antibiotic use, hospitalization, and advanced age. This patient has all the criteria for a suspected C. difficile infection. The stool was appropriately sent for ELISA Immunoassay for GDH antigen and Toxins A and B. If both are positive, then testing is consistent with C. difficile infection. If both are negative, then testing is not consistent with C. difficile infection. However, if one test is positive and the other is negative, then that is considered an intermediate test result. Then the stool must be sent for Nucleic acid amplification test (NAAT). The laboratory will then perform a NAAT for tcdB and tcdC genes. If this test is positive, then the patient is considered to have C. difficile infection. If this test is negative, then the patient is considered to not have the infection. It is important to note that the NAAT testing should ideally be sent before C. difficile infection treatment. However, if there is a high suspicion for the infection and the patient is showing signs sepsis, then early treatment is essential. With the abdominal pain and signs of early septic shock, it is important to get a KUB to rule out signs of toxic megacolon on imaging. A patient with signs of peritonitis will need an urgent surgical evaluation.
Which one of the following immunosuppressants is in the macrolide family?
Sirolimus is a macrolide antibiotic with potent immunosuppressant and antifungal properties. Tacrolimus and cyclosporine are calcineurin inhibitors. Mycophenolate is a nucleotide blocking agent.
A 35-year-old otherwise healthy female status post Roux-en-Y gastric bypass surgery presents to the ICU with abdominal pain mainly in the epigastric region with temperature of 101.5°F, blood pressure of 84/60 mm Hg with altered mental status after 4 L of crystalloid in the ED. A CT scan that does not demonstrate any bowel obstruction or internal hernia however a mildly dilated common bile duct with gallstones is visualized without signs of cholecystitis. On examination, she is jaundiced with epigastric tenderness to palpation. She has a slight elevation in her AST and ALT and direct bilirubin of 5 mg/dL. Aside from appropriate intensive care resuscitation, what is the next BEST step in the management of this patient?
Acute cholangitis should be suspected in patients with fever, abdominal pain, and jaundice (Charcot triad) and abnormal liver enzyme tests with signs of obstructive jaundice. This patient already has a CT scan that shows a mildly dilated common bile duct. CT imaging has a high sensitivity for bile duct dilation but low sensitivity for bile duct stones. A follow-up ultrasound is not necessary for this patient. Abdominal ultrasound has a high specificity for bile duct dilation and bile duct stones but variable sensitivity for bile duct dilation and bile duct stones. In a patient with Charcot triad and elevated liver enzymes with a normal CT scan and/or ultrasound, and MRCP is ordered with a higher diagnostic accuracy in identifying causes of biliary obstruction. However, this patient has evidence of Reynold Pentad defined by Charcot triad along with signs of end organ dysfunction such as altered mental status and hypotension consistent with signs of severe cholangitis. Patients with mild and moderate cholangitis generally respond well to early antibiotic therapy and biliary decompression within 24 to 48 hours. Patients with mild to moderate cholangitis who fail to respond to conservative management within 24 hours or those patients with severe (suppurative) cholangitis require biliary decompression urgently (within 24 hours). Endoscopic sphincterotomy with stone extraction and/or stent insertion is the treatment of choice. Endoscopic decompression is successful in 90% to 95% of patients after sphincterotomy. Endoscopic drainage has a significantly improved mortality and morbidity compared to surgical decompression. Percutaneous transhepatic biliary drainage can be performed when ERCP is unavailable or unsuccessful. Surgical decompression is used in patients whom ERCP and drainage have failed. Laparoscopic or open common bile duct exploration with decompression with or without placement of T-tube is the surgical choice. In this patient who is showing signs of hemodynamic instability and end organ dysfunction, both the surgical team and gastrointestinal team should get involved urgently. CT head is not the next best step as this patient’s clinical examination, imaging, and laboratory test results support cholangitis as the reason for the altered mental status with no lateralizing symptoms.
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