Gastrointestinal Clinical Case / MCQS / Uworld for Usmle step 2 and IFOM / case 5

 

Gastrointestinal Clinical Case  / MCQS / Uworld for Usmle step 2  and IFOM / case 5 with answer and explanation and references and Educational objective

A 35-year-old woman Is brought to the emergency department due to 3 days of progressive nausea, anorexia, malaise, abdominal pain, and lethargy. The patient Is a chronic carrier of hepatitis B virus and has not received any treatment. She has a history of injection drug use and completed a rehabilitation program 2 years ago, but recently started using drugs again. She drinks alcohol but does not use tobacco. Her temperature is 37.8 C (100.2 F). blood pressure is 106/64 mm Hg, and pulse is 114/min.

Mild tender hepatomegaly is present. Laboratory testing shows markedly elevated serum aminotransferase levels and a positive serum hepatitis D antigen. Acute liver failure due to hepatitis D virus superinfection Is suspected. Which of the following Is required to make a diagnosis of acute liver failure in this patient?

 

A.  Decreased urine output  . B.  Elevated portal venous pressure . C.  Features of liver cirrhosis . D.  Severe hyperbilirubinemia . E.  E. Signs of hepatic encephalopathy .

 

Answer : E

Explanation:

Acute liver failure
Etiology	• Viral hepatitis (eg, HSV; CMV; hepatitis A, B, D & 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, asterixis) • Synthetic liver dysfunction (INR >1.5)

ALT = alanine aminotransferase ,  AST = aspartate aminotransferase; CMV = cytomegalovirus;

HSV = herpes simplex virus .

Acute liver failure (ALF) Is a serious condition characterized by severe acute liver injury in a patient without cirrhosis or underlying liver disease. The diagnosis requires:

•      Severe acute liver Injury as evidenced by elevated aminotransferases (often >1000 U/L)

•      Signs of hepatic encephalopathy (HE)

•      Impaired hepatic synthetic function (defined as INR ≥1 .5)

The presence of HE differentiates ALF from acute hepatitis, which has a much better prognosis than ALF. In addition to varying degrees of HE, other common manifestations of ALF include fatigue, lethargy, nausea, vomiting, jaundice, pruritus, and right upper quadrant pain. The most common causes of ALF are drug toxicity (eg, acetaminophen overdose) and acute viral hepatitis (eg, hepatitis A virus, hepatitis B virus [HBV]). Other causes Include autoimmune hepatitis, ischemia, Wilson disease, and malignant infiltration of the liver.

Acute superinfection with hepatitis D virus carries a high risk of ALF development In intravenous drug users with chronic HBV. On further evaluation of this patient, clinical signs of HE and laboratory findings of INR ≥ 1.5 would be diagnostic of ALF.

(Choices A and B) Decreased urine output (due to intravascular volume depletion and decreased renal perfusion) and elevated portal venous pressure (due to increased resistance to blood flow through the inflamed liver) are both common in ALF. However, neither is specific for ALF or part of the diagnostic criteria.

(Choice C) Features of liver cirrhosis include fluid retention, jaundice, caput medusae , palmar erythema, muscle wasting, and gynecomastia. ALF includes some of these features (eg, jaundice. fluid retention). but it is characterized by acute liver injury in a patient without cirrhosis.

(Choice D) Severe hyperbilirubinemia is common in ALF and results from a combination of impaired conjugation and Impaired excretion of bilirubin. However, it is not a requirement for the diagnosis of ALF.

Educational objective:

Acute liver failure is defined as acute onset of severe liver injury with encephalopathy and impaired synthetic function (defined as INR ≥1.5) in a patient without cirrhosis or underlying liver disease. Drug toxicity and acute viral hepatitis are the most common causes.

 

References: 1. Acute liver failure. 2. Outcomes In adults with acute liver failure between 1998 and 2013: an observational cohort study. 3. The pathology of acute liver failure. New links : 1. Acute liver failure. 2. Outcomes In adults with acute liver failure between 1998 and 2013: an observational cohort study. 3. The pathology of acute liver failure.

 

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Gastrointestinal Clinical Case / MCQS / Uworld for Usmle step 2 and IFOM / case 4

 

Gastrointestinal Clinical Case  / MCQS / Uworld for Usmle step 2  and IFOM / case 4  with answer and explanation and references and Educational objective

An 80-year-old man Is evaluated for gradually worsening abdominal discomfort and distension for the past 3 days. He also has nausea and has had several episodes of vomiting, with his last bowel movement being 3 days ago. The patient underwent total hip arthroplasty 10 days ago due to a femoral neck fracture and was transferred to a rehabilitation facility for physical therapy. He has received acetaminophen and opioid analgesics for pain control. The patient also has hypertension, hyperlipidemia, coronary artery disease, and systolic heart failure. Temperature is 37.1 C (98.8 F), blood pressure is 110/70 mm Hg, and pulse is 90/min. The patient appears uncomfortable. The abdomen is distended and tympanitic with mild diffuse tenderness and hypoactive bowel sounds. There is no guarding or rebound tenderness. The rectal vault is empty.

Laboratory results are as follows:

Complete blood count

Hemoglobin                       12.6 g/dL

Platelets                            240,000/mm3

Leukocytes                        8,200/mm3

Serum chemistry

Sodium                               136 mEq/L

Potassium                           3.1 mEq/L

Blood urea nitrogen           18 mg/dL

Creatinine                           0.9 mg/dL

Calcium                              8.8 mg/dL

Glucose                             120 mg/dL

Abdominal CT scan reveals a dilated colon from the cecum to the splenic flexure. Oral contrast is visualized up to the distal colon. Which of the following is the most likely diagnosis for this patient?

A.  Acute infectious colitis . B.  Acute ischemic colitis . C.  Cecal volvulus . D.  Colonic pseudo-obstruction . E.  Opioid-lnduced constipation . F.   Postoperative Ileus . G.  Toxic megacolon .

 

Answer : D

Explanation :

Acute colonic pseudo-obstruction (Ogilvie syndrome)
Etiology	•      Nonoperatlve trauma •      Infection (eg, pneumonia) •      Cardiac (eg, heart failure, myocardial infarction) •      Abdominal/pelvic/orthopedic surgery •      Neurologic (eg, Parkinson disease, multiple sclerosis, Alzheimer disease)
Clinical findings	•      Abdominal distension, pain, nausea, vomiting . •      Constipation/obstipation or paradoxical diarrhea. •      If Ischemia/perforation : Guarding, rigidity, extreme tenderness. •      Partial/total colonic dilation without anatomic obstruction on CT scan.

This elderly patient who recently underwent a major orthopedic procedure now has abdominal pain, distension, nausea, and vomiting. ACT scan reveals colonic dilation with oral contrast visualized throughout the colon, suggesting no anatomic obstruction. This presentation is characteristic of acute colonic pseudo-obstruction (Ogilvie syndrome).

Acute colonic pseudo-obstruction more commonly occurs in men age >60. Predisposing conditions include nonoperative trauma, severe illness, and surgery, particularly In combination with metabolic abnormalities (eg, hypokalemia) or medication administration {eg, opioids). Postoperative Ogilvie syndrome tends to present 3-7 days after surgery.

The underlying mechanism Is likely related to interruption of the autonomic nervous system, possibly due to anesthesia, analgesia, or surgical trauma. As a result. Colonic dilation occurs, usually involving the cecum and ascending colon, although the entire colon may be involved. Increasing colonic dilation increases the risk of colonic Ischemia and perforation.

Diagnosis is confirmed with an abdominal CT scan as plain abdominal radiographs lack specificity.

(Choices A and G) Acute infectious colitis is likely to cause diarrhea, often with fever and leukocytosis, none of which are seen in this patient. Toxic megacolon is a potentially fatal complication of inflammatory or infectious (eg, Clostridium difficile) colitis that results in pathologic dilation of the colon. It is frequently marked by systemic toxicity (eg, fever, hypotension, leukocytosis) and preceded by manifestations of colitis (eg, diarrhea).

(Choice B) Acute ischemic colitis can occur postoperatively but is more commonly associated with vascular surgeries. it presents with moderate abdominal cramping , hematochezia, and occasionally leukocytosis and lactic acidosis.

(Choice C) Cecal volvulus is a mechanical obstruction from torsion of a mobile cecum and ascending colon. It can be easily visualized on an abdominal radiograph or CT scan. Most patients experience progressive abdominal pain with episodes of cramping.

(Choices E and F) Opioid analgesia is a common culprit in postoperative constipation but is unlikely to cause asymmetric colonic dilation or an empty rectal vault.

Postoperative Ileus can occur following any operation and results in uncoordinated intestinal motility and obstipation. Although symptoms may be similar to those of acute colonic pseudo-obstruction, postoperative ileus would not cause severe colonic dilation and usually develops before a return of bowel function (making it unlikely in this patient who had bowel movements after surgery).

Educational objective:

Acute colonic pseudo-obstruction (Ogilvie syndrome) is an uncommon postoperative complication characterized by abdominal pain, distension, and colonic dilation without radiographic evidence of an anatomic obstruction. Progressive colonic dilation can lead to colonic ischemia and perforation. Abdominal CT scan is the diagnostic test of choice.

References: 1.    Acute colonic pseudo-obstruction. New link : 1.   Acute colonic pseudo-obstruction.

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Gastrointestinal Clinical Case / MCQS / Uworld for Usmle step 2 and IFOM / case 3

 

Gastrointestinal Clinical Case  / MCQS / Uworld for Usmle step 2  and IFOM / case 3 with answer and explanation and references and Educational objective

A 40-year-old man comes to the office for evaluation of dysphagia. For the past 3 years, the patient has had difficulty swallowing solid foods and liquids, with symptoms worsening recently. He reports that it is easier to swallow standing upright. He has occasional regurgitation of undigested food and has lost 5 kg (11 lbs) over the past 6 months. The patient has no chest pain or muscle weakness. His only other medical problem is generalized anxiety disorder for which he takes sertraline. He does not use tobacco, alcohol. or recreational drugs. Vital signs are normal. His neck is supple without masses. Cardiopulmonary examination shows no abnormalities. Muscle strength is 5/5 in all 4 extremities, and deep tendon reflexes are 2+ symmetrically. Barium esophagogram Is shown in the exhibit. Which of the following is the patient's most likely diagnosis?

 

A.  Achalasia . B.  Esophageal cancer . C.  Esophageal web . D.  Globus sensation . E.  Polymyositis . F.   Zenker diverticulum .

 

Answer : A

Explanation:

Achalasia
Clinical presentation	•      Chrome dysphagia to solids & liquids, regurgitation •       Heartburn, weight loss
Diagnosis	•      Manometry: 1 LES resting pressure, incomplete LES •      relaxation, 1 peristalsis of distal esophagus •      Barium esophagram: Smooth "bird-beak" narrowing •      at gastroesophageal junction
Management	•     Upper endoscopy to exclude malignancy •     Laparoscopic myotomy or pneumatic balloon dilation •     Botulinum toxin injection, nitrates & CCB

CCB =calcium channel blocker ; LES = lower esophageal sphincter.

Chronic dysphagia to both solids and liquids, regurgitation, difficulty belching, and mild weight loss are all common manifestations of achalasia. Other symptoms include chest pain and heartburn; therefore, many patients are initially diagnosed with gastroesophageal reflux. On average, patients have symptoms for approximately 5 years before receiving a diagnosis of achalasia.

Achalasia is due to Impaired peristalsis of the distal esophagus and impaired relaxation of the lower esophageal sphincter (LES). This prevents food or liquid from passing through the LES until the hydrostatic pressure in the esophageal column is greater than the closing pressure of the sphincter. Being in the upright position increases the pressure in the esophagus and results in more effective swallowing.

Manometry is the most sensitive test and key to diagnosis. Barium esophagram, which may show a smooth "bird-beak" narrowing near the LES, can be helpful in patients with nondiagnostic manometry.

(Choice B) Esophageal cancer classically presents with dysphagia to solids, especially bread and meat, although tumors can eventually cause dysphagia to liquids as well.

Tobacco and alcohol use are major risk factors. In addition, the prolonged time course of this patient's symptoms and his relatively young age are less consistent with malignancy.

(Choice C) Esophageal webs are most commonly located in the upper esophagus and only cause mild focal narrowing (dysphagia to solids but not liquids). They are often associated with Iron deficiency (Plummer-Vinson syndrome).

(Choice D) Globus sensation Is a diagnosis of exclusion and is characterized by the sensation of a lump In the back of the throat. It is a functional disorder and does not cause any abnormalities on barium esophagram.

(Choice E) Polymyositis can present with dysphagia but usually affects the striated muscle in the upper third of the esophagus. and is associated with other symptoms of muscle weakness (eg, difficulty climbing stairs).

(Choice F) Zenker diverticulum, caused by an outpouching at the cricopharyngeal level of the esophagus, most commonly occurs in patients age >60 and presents with dysphagia, halitosis, and fullness of the throat.

Educational objective:

Achalasia commonly presents with chronic dysphagia to both solids and liquids, regurgitation, difficulty belching, and weight loss. Achalasia is caused by impaired peristalsis of the distal esophagus and failure of the lower esophageal sphincter to relax when food boluses reach it. Manometry is key to diagnosis. 

References: 1. Achalasia. 2. Achalasia: A review of clinical diagnosis, epidemiology, treatment and outcomes. New links : 1. Achalasia. 2. Achalasia: A review of clinical diagnosis, epidemiology, treatment and outcomes.

  

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