Gastrointestinal Clinical Case / MCQS / Uworld for Usmle step 2 and IFOM / case 8

 

Gastrointestinal Clinical Case  / MCQS / Uworld for Usmle step 2  and IFOM / case 8 with answer and explanation and references and Educational objective

A 37 -year-old hospitalized man Is evaluated for acute onset of intense periumbilical abdominal pain associated with nausea and vomiting. He has had 2 bowel movements since the pain started. The patient has a history of alcohol and intravenous heroin abuse. He was admitted 4 days ago for fever, chills, and shortness of breath and was diagnosed with acute bacterial endocarditis. His blood cultures grew staphylococcus aureus, and an echocardiogram showed vegetations on the mitral valve. He is currently being treated with Intravenous vancomycin. On examination, the patient appears in significant distress and Is restless. Temperature is 37.5 C (99.5 F), blood pressure is 150/90 mm Hg. pulse is 11 0/min and regular, and respirations are 18/min. Pupils are equal, round, and 3 mm In size. Lungs are clear to auscultation. A 3/6 holosystolic murmur is present over the apex. There is no third heart sound. On abdominal palpation, minimal diffuse tenderness Is present. There is no rigidity or rebound. Bowel sounds are decreased. Extremities are warm with normal pulses. There is no tremor. Abdominal x-rays reveal no free air or obstruction. Which of the following is the most likely diagnosis?

 

A Acalculous cholecystitis B. Acute pancreatitis C. Alcohol withdrawal D. lntraabdominal abscess E. Mesenteric Ischemia F. Opioid withdrawal G. Papillary muscle rupture

 

Answer : E

Explanation:

Acute mesenteric ischemia
Presentation	• Rapid onset of periumbilical pain (often severe) • Pain out of proportion to examination findings • Hematochezia (late complication)
Risk factors	• Atherosclerosis (acute on chronic) • Embolic source (thrombus, vegetations) • Hypercoagulable disorders
Laboratory findings	• Leukocytosis • Elevated amylase & phosphate levels • Metabolic acidosis (elevated lactate)
Diagnosis	• CT (preferred) or MR angiography • Mesenteric angiography, if diagnosis unclear

 

This patient most likely has acute mesenteric ischemia (AMI) due to embolism from a cardiac valve vegetation. AMI is most commonly due to abrupt arterial occlusion from either of the following:

•      Cardiac embolic events In the setting of atrial fibrillation, valvular disease (eg, infective endocarditis). or cardiovascular aneurysms

•      Acute thrombosis due to peripheral arterial disease or low cardiac output states .

AMI typically presents with sudden-onset, severe, poorly localized (visceral) midabdominal pain accompanied by nausea and vomiting. In early-stage ischemia, physical examination is typically unremarkable (eg, minimal diffuse tenderness) despite patients having severe pain out of proportion to the examination findings. If bowel infarction occurs, patients may develop more focal abdominal tenderness (due to local inflammation/infarction), peritoneal signs (eg, guarding, rebound tenderness). Rectal bleeding, and sepsis. Leukocytosis, elevated hemoglobin (hemoconcentration), elevated amylase, and metabolic acidosis (lactate) are frequently seen on laboratory testing.

(Choice A) Acalculous cholecystitis usually occurs in critically ill, hospitalized patients .  Patients often have jaundice as well as pain and/or a mass in the upper right quadrant.

(Choice B) Acute pancreatitis commonly produces nausea, vomiting, and epigastric pain radiating to the back. This patient's minimal abdominal tenderness, urge to defecate (common with AMI), and history of endocarditis make AMI a more likely diagnosis.

(Choice C) Alcohol withdrawal frequently presents with restlessness, diaphoresis, and tachycardia. In moderate-to-severe cases, it may also present with seizures, hallucinations, and altered mental status. Acute, severe abdominal pain is less likely.

(Choice D) lntraabdominal abscesses usually present subacutely with fever, focal abdominal tenderness, and weight loss.

(Choice F) Opiold withdrawal commonly presents with gastrointestinal manifestations. However, these are also usually accompanied by flulike symptoms and signs of sympathetic nervous system activation (eg, mydriasis, agitation, anxiety); bowel sounds are typically Increased rather than decreased.

(Choice G) Papillary muscle rupture Is a serious mechanical complication of acute myocardial infarction characterized by acute-onset hypotension and pulmonary edema with respiratory distress.

Educational objective:

Acute mesenteric Ischemia classically presents with acute-onset, severe, midabdominal pain out of proportion to physical examination findings. Progression to bowel infarction causes focal pain, peritoneal signs, rectal bleeding and sepsis.

 

References: 1.   Mesenteric Ischemia: Pathogenesis and challenging diagnostic and therapeutic modalities. 2.   The diagnosis of acute mesenteric ischemia: A systematic review and meta-analysis. 3.   Acute mesenteric Ischemia: A vascular emergency. New links : 1.   Mesenteric Ischemia: Pathogenesis and challenging diagnostic and therapeutic modalities. 2.   The diagnosis of acute mesenteric ischemia: A systematic review and meta-analysis. 3.   Acute mesenteric Ischemia: A vascular emergency.

 

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Gastrointestinal Clinical Case / MCQS / Uworld for Usmle step 2 and IFOM / case 7

 

Gastrointestinal Clinical Case  / MCQS / Uworld for Usmle step 2  and IFOM / case 7 with answer and explanation and references and Educational objective

A 20-year-old college student Is brought to the emergency department after his friend found that he Ingested large amounts of acetaminophen in a suicide attempt. The patient has been depressed since his girlfriend broke up with him a week ago, and he took approximately 30 pills of 500-mg acetaminophen 2 days ago to end his life. He has nausea and mild abdominal pain. His temperature is 36.7 C (98 F), blood pressure is 114/68 mm Hg, and pulse Is 94/min. Abdominal examination shows mild tender hepatomegaly. Serum acetaminophen level is high, and the patient is hospitalized for N-acetylcysteine therapy. During the hospital stay, he becomes markedly confused and incoherent. Repeat examination shows scleral icterus and asterixis. Current laboratory results and those obtained at the time of admission are as follows:

Liver function studies

Total bilirubin                               4.1mg/dL      (1.2 mg/dL )

Aspartate aminotransferase       8456 U/L       (96 U/L)

Alanine aminotransferase           9634 U/L        (70 U/L)

Prothrombin time                          120 sec          (18 sec )

Serum creatinine                          3.5 mg/dL      (1.1 mg/dL )

 

Which of the following Is the best next step in management of this patient?

 

A. Close monitoring only . B. Discontinue N-acetylcysteine . C. Initiate vitamin K supplementation . D. Perform liver biopsy . E. Refer to liver transplant center . F. Start glucocorticoid .

 

Answer : E

 

Explanation:

 

This patient has acute liver failure (ALF) due to acetaminophen toxicity. ALF is defined as severe acute liver Injury without underlying liver disease and is characterized by elevated aminotransferases (often >1000 U/L), hepatic encephalopathy (HE), and synthetic liver dysfunction (defined as prolonged prothrombin time (PT) with INR ≥1.5). Approximately only half of patients with ALF will survive without liver transplantation (LT). Reliable Indicators of worsening ALF include rising serum bilirubin and PT. as seen in this patient. Acute renal insufficiency, likely due to decreased renal perfusion, is common and portends a lower chance of recovery without LT. The degree of HE is also of prognostic importance as grade Ill HE (characterized by marked confusion and Incoherence, as seen In this patient) is associated with only a 40%-50% chance of spontaneous recovery. Cerebral edema is a potential complication of ALF that may lead to coma and brain stem herniation, and is the most common cause of death.

In ALF due to acetaminophen toxicity, L T is firmly indicated in patients with grade Ill or IV HE, PT >1 00 seconds, and serum creatinine >3.4 mg/dl (such as this patient). One-year survival following L T for ALF Is approximately 80%.

(Choices A and D ) Liver biopsy Is sometimes helpful in ALF of unclear etiology. This patient's ALF Is due to acetaminophen toxicity and his condition is worsening. Close monitoring alone would not be appropriate, and liver biopsy is unlikely to prevent the need for LT.

(Choice B) When administered within 8 hours of acetaminophen ingestion, N-acetylcysteine markedly improves the rate of recovery in acetaminophen overdose and may be beneficial in other etiologies of ALF. This patient, who presented 2 days after acetaminophen Ingestion, may obtain some benefit from N-acetylcysteine and should continue therapy while undergoing evaluation for LT.

(Choice C) This patient's prolonged PT reflects coagulopathy due to ALF rather than to vitamin K deficiency (which would be seen in patients with malnutrition). As a result, vitamin K supplementation has limited efficacy as it would not address the underlying cause.

(Choice F) Glucocorticoids are generally not indicated in ALF as they increase the risk of infection and have not demonstrated benefit in most etiologies of ALF. They may provide benefit In alcoholic hepatitis and in ALF due to autoimmune hepatitis.

Educational objective:

Liver transplantation should be considered in all patients with acute liver failure and indications that the disease Is worsening or failing to improve.

 

References: 1.   Determinants of outcome among patients with acute liver failure listed for liver transplantation In the United States. 2.   Fulminant hepatic failure : etiology and indications for liver transplantation. 3.   Acetaminophen-induced acute liver failure: results of a United States multicenter, prospective study. New links : 1-   Determinants of outcome among patients with acute liver failure listed for liver transplantation In the United States. 2-   Fulminant hepatic failure : etiology and indications for liver transplantation. 3-    Acetaminophen-induced acute liver failure: results of a United States multicenter, prospective study.

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Gastrointestinal Clinical Case / MCQS / Uworld for Usmle step 2 and IFOM / case 6

 

Gastrointestinal Clinical Case  / MCQS / Uworld for Usmle step 2  and IFOM / case 6 with answer and explanation and references and Educational objective

A 68-year-old man Is brought to the emergency department due to 2 days of progressive confusion and lethargy. His symptoms started approximately 4 days ago with malaise, nausea, and vomiting. The patient has hypertension and chronic back pain due to spinal stenosis. Laminectomy 4 years ago provided limited symptom improvement. The patient's medications Include daily losartan and as-needed hydrocodone-acetaminophen. His wife says that for the past 2 weeks he has been taking additional acetaminophen for a severe toothache. The patient smokes a pack of cigarettes and drinks 2 shots of Whiskey daily. He has a remote history of intravenous drug abuse. His blood pressure is 110/60 mm Hg, pulse is 108/min, and BMI is 32 kg/m2.

The patient is sleepy but wakes when spoken to and follows instructions. He is oriented to person and place. There is mild scleral icterus. Cardiopulmonary examination is unremarkable, and a smooth and tender liver edge is palpable 3 cm below the right costal margin. The patient has a mild napping tremor of both hands. Laboratory results are as follows:

Complete blood count

Hematocrit                                    42%

Platelets                                        160,000/mm3

Leukocytes                                    9000/mm3

Serum chemistry

Blood urea nitrogen                       32 mg/dL

Creatinine                                      1.9 mg/dL

 

Liver function studies

Total bilirubin                                 3.3 mg/dL

Alkaline phosphatase                    220 U/L

Aspartate Aminotransferase          3207 U/L

Alanine aminotransferase              4180 U/L

INR                                                  1.6 (normal 0.8-1.2)

 

 

Which of the following Is the most likely diagnosis in this patient?

A. Acute alcoholic hepatitis B. Hepatitis C Infection C. Ischemic hepatitis D. Liver cirrhosis E. Medication-Induced liver Injury F. Nonalcoholic steatohepatitis

 

Answer : E

Explanation:

Acute liver failure
Etiology	• Viral hepatitis (eg, HSV; CMV; hepatitis A, B, 0 & E) • Drug toxicity (eg, acetaminophen overdose, idiosyncratic) • Ischemia (eg, shock liver, Budd-Chiari syndrome) • Autoimmune hepatitis • Wilson disease • Malignant infiltration
Clinical presentation	• Generalized symptoms (eg, fatigue, lethargy, anorexia, nausea) • Right upper quadrant abdominal pain • Pruritus & jaundice due to hyperbilirubinemia • Renal Insufficiency • Thrombocytopenia • Hypoglycemia
Diagnostic  requirements	• Severe acute liver injury (AL T & AST often >1000 U/L) • Signs of hepatic encephalopathy (eg, confusion, aslerixis) • Synthetic liver dysfunction (INR >1.5)

ALT = alanine aminotransferase. AST = aspartate aminotransferase; CMV = cytomegalovirus;  HSV = herpes Simplex virus.

This patient has acute liver failure (ALF) likely due to acetaminophen toxicity in the setting of chronic alcohol use. Diagnosis of ALF requires the triad of elevated aminotransferases (markedly elevated in this patient). signs of hepatic encephalopathy (confusion, somnolence, and flapping tremor consistent with asterixis in this patient}. and synthetic liver dysfunction (evidenced by INR ≥1.5}. Cirrhosis or underlying liver disease should not be present.

Acetaminophen toxicity Is the most common cause of ALF in many developed countries and can be seen In Intentional overdose (suicide attempt} or accidental overdose In patients taking multiple sources of acetaminophen (such as this patient). Toxicity results from overproduction of the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI), which leads to hepatic necrosis. NAPQI Is normally safely detoxified through glucuronidation In the liver, but this pathway becomes overwhelmed in overdose. Chronic alcohol use Is thought to potentiate acetaminophen hepatotoxicity by depleting glutathione levels and Impairing the glucuronidation process. On the other hand, N-acetylcystelne Increases glutathione levels and binds to NAPQI, so It Is an effective antidote for acetaminophen overdose when given early.

Acute renal Insufficiency Is common In ALF, especially when acetaminophen Induced, due to the drug's direct renal tubular toxicity. Hyperbilirubinemia is common as well, but acetaminophen hepatotoxicity is characterized by relatively low serum bilirubin compared with that In other etiologies of ALF.

(Choice A) Acute alcoholic hepatitis typically causes mild to moderate aminotransferase elevation (<500 U/L} In patients who drink heavily (>100 g/day). The AST/AL T ratio Is usually >2:1

(Choice B) Hepatitis C causes chronic hepatitis and may to lead to cirrhosis but is not typically associated with ALF. Hepatitis A. B. D. and E are more typical causes of ALF.

(Choice C) Ischemic hepatitis can result from severe hypotension (eg, shock liver) or Budd-Chiari syndrome (hepatic vein thrombosis) and is a potential cause of ALF. This patient has not had significant hypotension and lacks right upper quadrant pain, which Is typically severe in Budd-Chiari syndrome.

(Choices D and F) Nonalcoholic steatohepatitis is a chronic condition that Is associated with metabolic syndrome and may lead to liver cirrhosis. Both nonalcoholic steatohepatitis and cirrhosis are characterized by normal to moderately elevated aminotransferase levels, and elevation >1000 U/L is not consistent with either diagnosis.

Educational objective:

Acute liver failure (ALF) Is characterized by elevated aminotransferases, encephalopathy, and INR≥1.5. Acetaminophen toxicity Is a common cause of ALF that may be potentiated by chronic alcohol use.

 

References: 1.   Acute liver failure. 2.   Acetaminophen-induced acute liver failure: results of a United States multicenter, prospective study. 3. Influence of acute and chronic alcohol intake on the clinical course and outcome In acetaminophen overdose. New links : 1.   Acute liver failure. 2.   Acetaminophen-induced acute liver failure: results of a United States multicenter, prospective study. 3. Influence of acute and chronic alcohol intake on the clinical course and outcome In acetaminophen overdose.

 

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