Gastroenterology Practice Questions

Q: A 49-year-old male, chronic alcoholic presented to the ER with complaints of fever, progressive lethargy, and confusion for 2-3 days. On examination, he was hypotensive with tachycardia, had a distended, diffusely tender abdomen, and a positive fluid wave. Abdominal ultrasound revealed an irregular liver outline with coarsened echotexture and gross ascites. Ascitic fluid analysis showed a WBC count of 1000/microL with 40% neutrophils. Regarding the most common organisms causing this condition, which of the following statements is FALSE?

Phenylalanine deaminase positive. ### Explanation **Diagnosis:** The patient has **Spontaneous Bacterial Peritonitis (SBP)**, a common complication of cirrhosis. The diagnosis is confirmed by an ascitic fluid absolute neutrophil count (ANC) ≥ 250 cells/mm³. In this case, ANC = 1000 (WBC) × 0.40 (Neutrophils) = **400 cells/mm³**. **Why Option D is Correct:** The most common organisms causing SBP are Gram-negative bacilli of the **Enterobacteriaceae** family, specifically *Escherichia coli* (most common) and *Klebsiella pneumoniae*. * **Phenylalanine Deaminase (PDA) test** is used to identify the *Proteus, Morganella,* and *Providencia* genera. * *E. coli* and *Klebsiella* are **PDA negative**. Therefore, stating they are PDA positive is false. **Analysis of Incorrect Options (True Statements for Enterobacteriaceae):** * **Option A:** Members of Enterobacteriaceae are characterized by their ability to **ferment glucose** with the production of acid (and sometimes gas). * **Option B:** They possess the enzyme nitrate reductase, which **reduces nitrates to nitrites** (this is also the basis for the dipstick test in UTIs). * **Option C:** They are **Oxidase negative**, which distinguishes them from other Gram-negative rods like *Pseudomonas*. **Clinical Pearls for NEET-PG:** 1. **SBP Definition:** Ascitic fluid ANC ≥ 250/mm³ with a positive culture (monomicrobial) and no evidence of a surgically treatable intra-abdominal source. 2. **Culture-Negative Neutrocytic Ascites (CNNA):** ANC ≥ 250/mm³ but negative culture; treated the same as SBP. 3. **Treatment of Choice:** Third-generation cephalosporins (e.g., **Cefotaxime**). 4. **Albumin Therapy:** Administered (1.5g/kg on day 1, 1g/kg on day 3) to prevent Hepatorenal Syndrome if Creatinine >1mg/dL, BUN >30mg/dL, or Bilirubin >4mg/dL [1].

Q: Pseudo-hemoptysis is most commonly associated with which organism?

Serratia Marcescens. **Explanation:** **Pseudo-hemoptysis** refers to the appearance of blood in the sputum when no actual hemorrhage has occurred. This phenomenon is most characteristically associated with **Serratia marcescens**, a Gram-negative rod belonging to the Enterobacteriaceae family. **Why Serratia marcescens is correct:** Certain strains of *Serratia marcescens* produce a secondary metabolite called **prodigiosin**. This is a tripyrrole pigment that is naturally **bright red** in color. When these bacteria colonize the respiratory tract (often in hospitalized or immunocompromised patients), the red pigment can discolor the sputum, mimicking the appearance of fresh blood (hemoptysis). This "red sputum" can lead to diagnostic confusion unless the clinician is aware of this microbiological quirk. **Analysis of Incorrect Options:** * **Streptococcus:** While *S. pneumoniae* can cause "rusty sputum" due to the breakdown of red blood cells in pneumonia, it does not produce a red pigment that mimics frank blood. * **E. coli:** Although a common Gram-negative pathogen, it does not produce red pigments; its colonies are typically grayish-white on standard media. * **Respiratory Syncytial Virus (RSV):** This is a common cause of bronchiolitis and pneumonia, but it does not produce pigments. Any blood seen in RSV would be true hemoptysis due to mucosal inflammation. **NEET-PG High-Yield Pearls:** * **Serratia marcescens** is a common cause of **nosocomial infections** (UTIs, pneumonia, and bacteremia) and is often multi-drug resistant. * It is known for its ability to grow on starchy foods and in damp environments (like bathroom tiles), forming a characteristic pink/red film. * **Differential Diagnosis of Pseudo-hemoptysis:** Besides *Serratia*, consider Rifampicin use (orange-red secretions) or bleeding from the nasopharynx/GI tract (pseudo-hemoptysis vs. hematemesis).

Q: A patient presents with dysphagia and regurgitation. Esophageal manometry reveals ineffective esophageal motility. Which of the following is NOT a cause of this condition?

Gastroesophageal reflux disease. **Explanation:** The question asks to identify which condition is **NOT** a cause of **Ineffective Esophageal Motility (IEM)**. IEM is a manometric diagnosis characterized by low-amplitude or failed peristaltic contractions in the distal esophagus. **1. Why Gastroesophageal Reflux Disease (GERD) is the correct answer:** While GERD is frequently **associated** with IEM, it is generally considered a **consequence** rather than the primary cause [1]. In patients with GERD, the lack of effective peristalsis leads to impaired bolus clearance and prolonged acid exposure, worsening the reflux [1]. However, the options A, B, and C represent primary etiologies that directly damage the esophageal myenteric plexus or musculature, leading to motility failure. **2. Analysis of Incorrect Options:** * **A. Degenerative neurons:** Primary esophageal motility disorders (like Achalasia or IEM) are often idiopathic, resulting from the selective loss or degeneration of inhibitory and excitatory neurons in the myenteric (Auerbach’s) plexus [1]. * **B. Chagas disease:** Caused by *Trypanosoma cruzi*, this infection leads to the destruction of the intramural nerve plexuses of the esophagus, resulting in "Megaesophagus" and secondary achalasia/IEM. * **C. Herpes zoster infection:** Viral infections (including VZV and HSV) can cause ganglionitis of the myenteric plexus, leading to acute or chronic esophageal dysmotility. **3. NEET-PG High-Yield Pearls:** * **IEM Definition:** Defined on High-Resolution Manometry (HRM) as >50% of swallows being ineffective (DCI < 450 mmHg·s·cm) [1]. * **Systemic Sclerosis (Scleroderma):** The most common systemic cause of IEM, characterized by "Patulous Esophagus" and absent peristalsis. * **Clinical Presentation:** Patients typically present with dysphagia and regurgitation, but many are asymptomatic until secondary GERD develops [1].

Q: Colonic pseudo-obstruction occurs in all of the following conditions except?

Hyperthyroidism. Colonic pseudo-obstruction (Ogilvie’s syndrome or chronic intestinal pseudo-obstruction) is a clinical syndrome characterized by signs and symptoms of mechanical obstruction of the small or large bowel in the absence of an anatomic lesion [1]. It is primarily caused by disorders affecting the **enteric nerves or smooth muscles**, leading to impaired peristalsis. **Why Hyperthyroidism is the correct answer:** Hyperthyroidism is associated with **increased** gastrointestinal motility, often leading to hyperdefecation or diarrhea. In contrast, it is **Hypothyroidism** that is a well-known cause of colonic pseudo-obstruction and constipation due to metabolic slowing and decreased gut motility [1]. **Analysis of Incorrect Options:** * **Diabetes Mellitus:** Chronic hyperglycemia leads to autonomic neuropathy. Damage to the enteric nervous system (visceral neuropathy) commonly results in gastroparesis and colonic pseudo-obstruction [1]. * **Scleroderma (Systemic Sclerosis):** This condition causes progressive atrophy of the gastrointestinal smooth muscle and subsequent fibrosis. It is a classic cause of chronic intestinal pseudo-obstruction [1]. * **Dermatomyositis:** Similar to other connective tissue disorders, it can involve the smooth muscles of the GI tract or lead to vasculopathy, resulting in dysmotility and pseudo-obstruction. **NEET-PG High-Yield Pearls:** * **Acute Colonic Pseudo-obstruction (Ogilvie’s Syndrome):** Typically seen in elderly, bedridden patients with systemic infections or post-surgery (especially orthopedic or pelvic surgery). * **Electrolyte Imbalances:** Hypokalemia, hypocalcemia, and hypomagnesemia are common metabolic triggers for pseudo-obstruction. * **Drug-induced:** Opioids, anticholinergics, and calcium channel blockers are frequent pharmacological culprits. * **Management:** Neostigmine is the pharmacological treatment of choice for acute cases (if no contraindications like bradycardia exist).

Q: A patient presents with nonprogressive dysphagia exclusively for solids. A barium study reveals proximal esophageal dilatation with distal constriction. What is the most likely diagnosis?

Lower esophageal Ring. ### Explanation The clinical presentation of **nonprogressive dysphagia exclusively for solids** is the hallmark of a structural narrowing rather than a motility disorder or a rapidly growing malignancy. **1. Why Lower Esophageal Ring (Schatzki Ring) is correct:** A Schatzki ring is a thin, mucosal diaphragm located at the squamocolumnar junction (B-line). It typically presents with **intermittent, nonprogressive** dysphagia for solids, often triggered by poorly chewed meat or bread (the "Steakhouse Syndrome"). On barium swallow, it appears as a smooth, symmetric, thin annular constriction. The proximal esophagus may show mild dilatation due to the mechanical obstruction at the distal end. **2. Why other options are incorrect:** * **Peptic Stricture:** While it causes solid food dysphagia, it is usually **progressive** and associated with a long-standing history of GERD/heartburn. * **Carcinoma Esophagus:** This presents with **rapidly progressive** dysphagia (solids then liquids) and is almost always accompanied by significant weight loss and constitutional symptoms. * **Achalasia Cardia:** This is a motility disorder characterized by **paradoxical dysphagia** (more difficulty with liquids or both simultaneously) and is usually progressive. Barium swallow shows a "Bird’s beak" appearance, not a focal ring. **3. NEET-PG High-Yield Pearls:** * **Schatzki Ring:** Most common cause of intermittent solid food bolus impaction. Treatment is endoscopic dilation. * **Plummer-Vinson Syndrome:** Triad of iron deficiency anemia, glossitis, and **proximal** esophageal webs (increased risk of SCC). * **Dysphagia Algorithm:** * Solids + Liquids = Motility (Achalasia, DES). * Solids only (Progressive) = Structural (Stricture, Cancer). * Solids only (Intermittent) = Ring/Web.

Q: A 74-year-old man develops severe, steady, mild abdominal pain approximately 30 minutes after eating. He has lost 12 kg over the past few months because he wants to avoid the pain after eating. Abdominal examination during an asymptomatic interval is normal. Stool guaiac examination results are negative, as are colonoscopy and barium studies. The complete blood count is normal. What is the most likely diagnosis?

Mesenteric angina. The clinical presentation of **post-prandial abdominal pain** (occurring 30–60 minutes after meals), significant **weight loss**, and **"food fear"** (sitophobia) in an elderly patient is classic for **Chronic Mesenteric Ischemia**, also known as **Mesenteric Angina**. **1. Why Mesenteric Angina is Correct:** The pathophysiology is analogous to stable angina of the heart. Digestion requires increased blood flow to the gut. In the presence of atherosclerotic narrowing of the mesenteric arteries (usually involving at least two of the three major vessels: celiac, SMA, or IMA), the blood supply cannot meet this increased demand, leading to intestinal ischemia and severe pain. The physical exam is typically unremarkable ("pain out of proportion to physical findings"), and standard GI investigations like colonoscopy and barium studies are negative because the pathology is vascular, not mucosal [1]. **2. Why Incorrect Options are Wrong:** * **Acute Sigmoid Diverticulitis:** Presents with acute left lower quadrant pain, fever, and leukocytosis, rather than chronic post-prandial pain and weight loss. * **Colorectal Cancer:** While it causes weight loss, it usually presents with altered bowel habits, iron deficiency anemia, or a positive stool guaiac test (this patient’s guaiac and colonoscopy were negative) [1]. * **Meckel’s Diverticulitis:** Typically presents in younger patients with painless lower GI bleeding or features of acute appendicitis/obstruction. **Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Conventional Angiography (though CT Angiography is the initial test of choice). * **Triad:** Post-prandial pain, weight loss, and abdominal bruit (bruit is present in ~50% of cases). * **Risk Factors:** History of smoking, CAD, or peripheral vascular disease. * **Management:** Revascularization (Stenting or Bypass).

Question 1

A man who had undergone total gastrectomy remains well for five years. Then he develops anaemia. What is the most likely cause of this anaemia?

Accepted Answer

Vitamin B12 deficiency

Answer

Protein deficiency

Answer

Zinc deficiency

Answer

Folic acid deficiency

Question 2

A 49-year-old male, chronic alcoholic presented to the ER with complaints of fever, progressive lethargy, and confusion for 2-3 days. On examination, he was hypotensive with tachycardia, had a distended, diffusely tender abdomen, and a positive fluid wave. Abdominal ultrasound revealed an irregular liver outline with coarsened echotexture and gross ascites. Ascitic fluid analysis showed a WBC count of 1000/microL with 40% neutrophils. Regarding the most common organisms causing this condition, which of the following statements is FALSE?

Accepted Answer

Phenylalanine deaminase positive

Answer

Ferment glucose with acid production

Answer

Reduce nitrates to nitrites

Answer

Oxidase negative

Question 3

Pseudo-hemoptysis is most commonly associated with which organism?

Accepted Answer

Serratia Marcescens

Answer

Streptococcus

Answer

E. coli

Answer

Respiratory Syncytial Virus (RSV)

Question 4

A patient presents with dysphagia and regurgitation. Esophageal manometry reveals ineffective esophageal motility. Which of the following is NOT a cause of this condition?

Accepted Answer

Gastroesophageal reflux disease

Answer

Degenerative neurons

Answer

Chagas disease

Answer

Herpes zoster infection

Question 5

Which of the following is FALSE regarding ascites?

Accepted Answer

Ascites can only be recognized clinically when the amount of fluid exceeds 1500 ml.

Answer

Shifting dullness is absent when there is a very large accumulation of fluid.

Answer

In cirrhosis, obstruction to the venous outflow of the liver is due to obliterative fibrosis of the infrahepatic venous bed.

Answer

All of the above are true statements about ascites.

Question 6

Colonic pseudo-obstruction occurs in all of the following conditions except?

Accepted Answer

Hyperthyroidism

Answer

Diabetes mellitus

Answer

Dermatomyositis

Answer

Scleroderma

Question 7

A 40-year-old patient, a known case of cirrhosis, develops an acute episode of GI bleed. Initial therapy was given for 6 hours. Which of the following procedures is most useful?

Accepted Answer

Urgent endoscopy

Answer

Nasogastric aspiration

Answer

Sedation

Answer

Ultrasound

Question 8

A 30-year-old male presents with chronic diarrhea, anemia, and elevated liver enzymes. Which of the following is the most likely associated finding?

Accepted Answer

Anti-endomysial antibody

Answer

Antimitochondrial antibody

Answer

Anti-smooth muscle antibody

Answer

Antinuclear antibody

Question 9

A patient presents with nonprogressive dysphagia exclusively for solids. A barium study reveals proximal esophageal dilatation with distal constriction. What is the most likely diagnosis?

Accepted Answer

Lower esophageal Ring

Answer

Peptic Stricture

Answer

Carcinoma esophagus

Answer

Achalasia Cardia

Question 10

A 74-year-old man develops severe, steady, mild abdominal pain approximately 30 minutes after eating. He has lost 12 kg over the past few months because he wants to avoid the pain after eating. Abdominal examination during an asymptomatic interval is normal. Stool guaiac examination results are negative, as are colonoscopy and barium studies. The complete blood count is normal. What is the most likely diagnosis?

Accepted Answer

Mesenteric angina

Answer

Acute sigmoid diverticulitis

Answer

Colorectal cancer

Answer

Meckel's diverticulitis

Gastroenterology — MCQs

Gastroenterology — MCQs

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