Gastrointestinal Infections Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Gastrointestinal Infections. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Gastrointestinal Infections Indian Medical PG Question 1: A patient presents with bloody diarrhea after eating undercooked meat. Which bacterial pathogen is most likely?
- A. Salmonella typhi
- B. Shigella dysenteriae
- C. Vibrio cholerae
- D. Escherichia coli O157:H7 (Correct Answer)
Gastrointestinal Infections Explanation: ***Escherichia coli O157:H7***
- **Enterohemorrhagic E. coli (EHEC)** is the classic cause of **bloody diarrhea** following consumption of **undercooked ground beef** or hamburgers, producing **Shiga toxins** that cause **hemorrhagic colitis**.
- Can lead to serious complications like **hemolytic uremic syndrome (HUS)**, particularly in children and elderly patients.
*Salmonella typhi*
- **Salmonella typhi** specifically causes **typhoid fever** with sustained fever, headache, and rose spots, not acute bloody diarrhea from undercooked meat.
- While non-typhoidal Salmonella can cause gastroenteritis, it typically produces **non-bloody diarrhea** and is more associated with poultry and eggs.
*Shigella dysenteriae*
- Although it causes **bloody diarrhea** and severe **dysentery**, transmission is primarily **person-to-person** through the fecal-oral route or contaminated water.
- Not typically associated with **undercooked meat consumption** but rather with poor sanitation and contaminated produce.
*Vibrio cholerae*
- Causes **cholera** with characteristic profuse, **watery diarrhea** ("rice-water stools") leading to severe dehydration, not bloody diarrhea.
- Transmission occurs through contaminated **water and seafood**, not undercooked meat.
Gastrointestinal Infections Indian Medical PG Question 2: A child presents with abdominal pain, arthralgia, hematuria, and hypertension. What is the diagnosis?
- A. Dengue
- B. Rheumatic fever
- C. Henoch-Schönlein Purpura
- D. Hemolytic uremic syndrome (Correct Answer)
Gastrointestinal Infections Explanation: ***Hemolytic uremic syndrome***
- The combination of **abdominal pain**, **hematuria**, and **hypertension** in a child, particularly after a diarrheal illness, is highly suggestive of **hemolytic uremic syndrome (HUS)** [1], [2].
- HUS is characterized by **microangiopathic hemolytic anemia**, **thrombocytopenia**, and **acute kidney injury**, which can manifest as hematuria and hypertension [1], [2].
*Dengue*
- While **abdominal pain** and **arthralgia** can be symptoms of dengue, it typically also presents with **fever**, **rash**, and **bleeding manifestations** like petechiae or mucosal bleeding.
- Dengue does not typically cause **hematuria** with **hypertension** as a primary feature of renal involvement.
*Rheumatic fever*
- **Rheumatic fever** is characterized by **arthralgia** (migratory arthritis), but it is primarily a sequela of **Streptococcal pharyngitis** and presents with **carditis**, **chorea**, **erythema marginatum**, and **subcutaneous nodules**.
- It does not typically cause the combination of **abdominal pain**, **hematuria**, and **hypertension** seen here.
*Henoch-Schönlein Purpura*
- **Henoch-Schönlein Purpura (HSP)** involves **abdominal pain**, **arthralgia**, and **hematuria**, and can sometimes cause hypertension.
- However, the hallmark of HSP is a **palpable purpuric rash** on the lower extremities and buttocks, which is not mentioned in the patient's presentation.
Gastrointestinal Infections Indian Medical PG Question 3: A 17 year old adolescent, presented with fever since one week which is step-ladder in pattern. He also has loose stools which are "pea-soup" in consistency. Rose spots are seen on his body. He is most probably infected with:
- A. Salmonella typhi (Correct Answer)
- B. Adenovirus
- C. Rotavirus
- D. Vibrio cholerae
Gastrointestinal Infections Explanation: ***Salmonella typhi***
- The combination of **step-ladder fever**, **"pea-soup" diarrhea**, and **rose spots** is a classic presentation of **typhoid fever**, caused by *Salmonella typhi* [1].
- This bacterial infection predominantly affects the gastrointestinal tract and can lead to systemic symptoms [1].
*Adenovirus*
- **Adenovirus** typically causes **respiratory tract infections**, **conjunctivitis**, or **gastroenteritis**, but not with the specific symptom profile of step-ladder fever or rose spots.
- While it can cause diarrhea, it's usually not described as "pea-soup" and lacks the other systemic features.
*Rotavirus*
- **Rotavirus** is a common cause of **severe gastroenteritis** in infants and young children, characterized by **watery diarrhea** and vomiting.
- It does not present with step-ladder fever or rose spots, which are pathognomonic for typhoid.
*Vibrio cholerae*
- **Vibrio cholerae** causes **cholera**, an acute diarrheal illness characterized by **profuse watery diarrhea** (often described as "rice-water stools") and rapid dehydration.
- It does not typically cause step-ladder fever or skin manifestations like rose spots.
Gastrointestinal Infections Indian Medical PG Question 4: Which of the following pathogens are associated with watery diarrhea after an incubation period of 8 to 14 hours?
- A. Rotavirus and Norwalk virus
- B. Shigella and Salmonella
- C. S. aureus and Bacillus cereus
- D. Bacillus cereus and Clostridium perfringens (Correct Answer)
Gastrointestinal Infections Explanation: **Bacillus cereus and Clostridium perfringens**
- Both *Bacillus cereus* diarrheal type and *Clostridium perfringens* are known to cause **watery diarrhea** after an incubation period of **8 to 14 hours**.
- This longer incubation period is typical for toxins produced in the gut after ingestion of spores or large numbers of bacteria.
*Rotavirus and Norwalk virus*
- **Rotavirus** typically has an incubation period of 1-3 days and causes **severe watery diarrhea**, especially in infants and young children.
- **Norwalk virus** (norovirus) usually has an incubation period of 12-48 hours and causes **acute gastroenteritis** with vomiting and watery diarrhea.
*Shigella and Salmonella*
- **Shigella** causes **dysentery** (bloody diarrhea) with a shorter incubation period (1-2 days) rather than watery diarrhea.
- **Salmonella** can cause **inflammatory diarrhea** (salmonellosis) with an incubation period ranging from 6 hours to 6 days, often shorter than 8-14 hours for typical infections.
*S. aureus and Bacillus cereus*
- **Staphylococcus aureus** causes vomiting and diarrhea due to preformed toxin, with a very short incubation period of **1-6 hours**.
- While *Bacillus cereus* can cause emetic (vomiting) or diarrheal type illness, the emetic form has a 1-6 hour incubation period, which is not consistent with the 8-14 hour window.
Gastrointestinal Infections Indian Medical PG Question 5: Which of the following statements about Enterohemorrhagic E. coli (EHEC) is false?
- A. Sereny test is positive (Correct Answer)
- B. Commonly causes HUS
- C. Bloody diarrhea and HUS linked to O157:H7
- D. Produces Shiga-like toxin
Gastrointestinal Infections Explanation: ***Sereny test is positive***
- The **Sereny test** assesses the invasiveness of bacteria by observing their ability to invade and replicate in epithelial cells, typically in guinea pig conjunctiva.
- *Enterohemorrhagic E. coli* (**EHEC**) is **non-invasive**; its pathogenicity stems from its production of **Shiga-like toxins**, not from cellular invasion, making a positive Sereny test statement false.
*Commonly causes HUS*
- **EHEC**, particularly serotype **O157:H7**, is a well-known cause of **Hemolytic Uremic Syndrome (HUS)**, especially in children and the elderly.
- The **Shiga-like toxins** produced by EHEC are absorbed into the bloodstream, damaging endothelial cells and leading to the characteristic triad of **hemolytic anemia**, **thrombocytopenia**, and **acute kidney injury** seen in HUS.
*Bloody diarrhea and HUS linked to O157:H7*
- **EHEC O157:H7** is the most common serotype associated with outbreaks of **bloody diarrhea** and the subsequent development of **HUS**.
- The toxins cause widespread damage to the intestinal lining, leading to **hemorrhagic colitis** (bloody diarrhea), and can then disseminate to distant organs like the kidneys, causing HUS.
*Produces Shiga-like toxin*
- The primary virulence factor of **EHEC** is the production of **Shiga-like toxins** (also known as **verotoxins**), specifically Stx1 and Stx2.
- These toxins inhibit protein synthesis in eukaryotic cells, leading to cell death and tissue damage, which contribute to the severe gastrointestinal symptoms and systemic complications like HUS.
Gastrointestinal Infections Indian Medical PG Question 6: What is the most common extra-intestinal complication of Shigellosis?
- A. Pneumonia
- B. Meningitis
- C. HUS
- D. Reactive arthritis (Correct Answer)
Gastrointestinal Infections Explanation: ***Reactive arthritis***
- **Reactive arthritis** is triggered by a prior infection, such as *Shigellosis*, and is the most common extra-intestinal complication, especially in HLA-B27 positive individuals [1].
- It typically presents with a triad of **arthritis**, **urethritis**, and **conjunctivitis**, though not all symptoms may be present [1].
*Pneumonia*
- While pneumonia can occur in severely ill patients, it is not a common nor specific extra-intestinal complication directly linked to the pathogenesis of *Shigellosis*.
- Respiratory complications are rare in uncomplicated cases of shigellosis.
*Meningitis*
- **Meningitis** is a rare and severe complication, primarily seen in young children or immunocompromised individuals, and is not the most common extra-intestinal manifestataion.
- It suggests systemic spread of the bacteria beyond the gastrointestinal tract, which is uncommon.
*HUS*
- **Hemolytic Uremic Syndrome (HUS)** is a well-known complication of *E. coli* O157:H7 (Shiga toxin-producing E. coli, STEC), rather than *Shigella* species.
- While some *Shigella* strains produce Shiga toxin, HUS is far less common in *Shigellosis* compared to STEC infections.
Gastrointestinal Infections Indian Medical PG Question 7: Which condition is characterized by bacteremia?
- A. Typhoid fever (Correct Answer)
- B. Shigella infection
- C. Cholera infection
- D. Diphtheria infection
Gastrointestinal Infections Explanation: ***Typhoid fever***
- Typhoid fever, caused by **Salmonella Typhi**, is characterized by **bacteremia**, as the bacteria invade the bloodstream from the gut.
- The systemic spread of bacteria leads to classic symptoms such as **high fever**, headache, and abdominal pain.
*Shigella infection*
- Shigella infections, primarily cause **dysentery** by invading the colonic mucosa, leading to **bloody diarrhea**.
- While localized to the gut, **bacteremia is rare** and typically seen only in severely immunocompromised individuals.
*Cholera infection*
- Cholera, caused by **Vibrio cholerae**, is a **non-invasive** infection that primarily affects the small intestine.
- It produces a **toxin** that causes massive fluid and electrolyte loss, leading to severe **watery diarrhea**, but **does not typically involve bacteremia**.
*Diphtheria infection*
- Diphtheria is caused by **Corynebacterium diphtheriae**, which produces a **toxin** that enters the bloodstream and can affect distant organs (heart, nerves).
- The bacterial infection itself is usually localized to the upper respiratory tract; **bacteremia is not a characteristic feature** of diphtheria.
Gastrointestinal Infections Indian Medical PG Question 8: Identify the condition shown in the image.
- A. Villous adenoma
- B. Hyperplastic polyp
- C. Juvenile polyp
- D. Peutz-Jeghers syndrome (Correct Answer)
Gastrointestinal Infections Explanation: ***Juvenile polyp***
- Juvenile polyps are commonly found in children and present as **solitary lesions**, usually in the rectum [1].
- They typically appear **smooth**, with a characteristic lobulated surface, emphasizing their benign nature.
*Villous adenoma*
- Villous adenomas are characterized by **frond-like projections** and have a higher risk of malignant transformation [2].
- These lesions usually occur in adults and are typically larger and more **invasive** compared to juvenile polyps [2].
*Hyperplastic polyp*
- Hyperplastic polyps are small, **benign lesions** that result from epithelial overgrowth with a typical **smooth surface** [3].
- They are usually found in the colon and do not present with the distinctive features of juvenile polyps.
*Peutz-Jeghers polyp*
- Peutz-Jeghers polyps are associated with **Peutz-Jeghers syndrome** and exhibit a **hamartomatous** appearance, often protruding from various gastrointestinal sites [1].
- These polyps are typically more **complex** and can be found in older children and adults, differing significantly from juvenile polyps [1].
**References:**
[1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, p. 813.
[2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 371-372.
[3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 811-813.
Gastrointestinal Infections Indian Medical PG Question 9: A 3-year-old female child sleeping in a thatched hut woke up in the middle of the night screaming. Her mother thought the child had a nightmare and tried to pacify her. After some time, she noticed that the child was sweating profusely and the hands were becoming cold. The child also vomited a couple of times. The mother immediately rushed the child to the emergency services. Her pulse was 150/minute and her BP 90/60 mm Hg. This child is likely to have -
- A. Scorpion envenomation (Correct Answer)
- B. Food poisoning
- C. Snakebite
- D. Septic shock
Gastrointestinal Infections Explanation: ***Scorpion envenomation***
- The combination of **profuse sweating**, **cold hands**, **vomiting**, **tachycardia**, and **hypotension with shock** (BP 90/60 mm Hg is low for a 3-year-old) in a child sleeping in a thatched hut (a common habitat for scorpions) is highly suggestive of **scorpion envenomation**.
- **Autonomic storm** with both sympathetic and parasympathetic activation is characteristic, leading to symptoms like sweating, vomiting, and cardiovascular instability.
- Scorpion envenomation can cause **initial hypertension** followed by **cardiogenic shock and hypotension** in severe cases, as seen here with cold peripheries and tachycardia.
*Food poisoning*
- While food poisoning can cause **vomiting** and malaise, it typically presents with **diarrhea** and generally does not cause the severe autonomic features like profuse sweating, cold periphery, or the degree of cardiovascular instability described here.
- The sudden onset during sleep in a thatched hut and the specific constellation of symptoms point away from a simple foodborne illness.
*Snakebite*
- Snakebites, particularly from **neurotoxic snakes**, can cause some autonomic symptoms, but they are more commonly associated with **local swelling**, **fang marks**, and progressive **neurological symptoms** like ptosis, ophthalmoplegia, and respiratory paralysis.
- **Viperine envenomation** typically causes **local swelling, bleeding disorders**, and hypotension but without the specific autonomic storm pattern (profuse sweating, vomiting) seen in scorpion sting.
*Septic shock*
- Septic shock would present with signs of severe infection such as **fever** (though sometimes hypothermia in children), **lethargy**, and ultimately **hypotension** with poor perfusion and organ dysfunction.
- There is no mention of an underlying infection or prodromal illness, and the sudden onset of specific autonomic symptoms during sleep in a thatched hut is more characteristic of envenomation rather than sepsis.
Gastrointestinal Infections Indian Medical PG Question 10: A young man back from leisure trip has swollen knee joints & foreign body sensation in eyes. Likely cause is -
- A. Behcet's disease
- B. SLE
- C. Reiter's syndrome (Correct Answer)
- D. Sarcoidosis
Gastrointestinal Infections Explanation: REITER'S SYNDROME [1]
- Reiter's syndrome, also known as **reactive arthritis**, is characterized by the classic triad of **arthritis**, **conjunctivitis** (foreign body sensation in eyes), and **urethritis** [1].
- It often develops after a **genitourinary or gastrointestinal infection**, which aligns with a recent leisure trip [1].
*Behcet's disease*
- Behcet's disease primarily presents with recurrent **oral and genital ulcers**, along with **uveitis** and **skin lesions**.
- While arthritis can occur, the combination of specific eye foreign body sensation and a recent trip isn't as characteristic as for Reiter's.
*SLE*
- **Systemic lupus erythematosus (SLE)** is a systemic autoimmune disease with diverse manifestations, including polyarthritis and serositis.
- **Conjunctivitis** as a primary eye symptom or a direct association with a preceding infection/trip is less typical compared to Reiter's syndrome.
*Sarcoidosis*
- **Sarcoidosis** is a multisystem inflammatory disease often involving the **lungs, skin, and lymph nodes**, and can cause arthritis.
- However, its acute presentation with foreign body sensation in the eyes and post-trip history is not its common debut.
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