Food Poisoning — MCQs
A child with fever with abdominal cramps & pus in stools, causative organism is ?
Food poisoning with incubation period of 1-6 hours is most probably caused by
A patient presents with a history of pastry intake causing food poisoning. What is the most likely causative agent?
An individual who runs a methanol liquor racket and diverts the effluent into a pond which is used by people. He is punishable under ___ IPC:-
A 34-year-old woman is seen in the emergency department. About 5 hours previously, she began to have nausea, vomiting, abdominal cramps, and diarrhea. She then developed double vision, which prompted her to ask her husband to bring her to the emergency department. When she is asked to go into the examining room, she stumbles. When she tries to answer questions, her voice sounds odd and she seems to mumble. Physical examination demonstrates a dry mouth, drooping eyelids, markedly diminished pupillary light reflex, a flaccid facial expression, and difficulty in opening her mouth. Within an hour, her condition has markedly deteriorated. She can no longer stand and is intubated because of difficulty breathing. Which of the following microbial species is MOST likely to have caused her condition?
A 22-year-old male had an outing with his friends and developed fever of 38.5degC, abdominal pain, diarrhea and vomiting after eating chicken salad 24 h back. Two of his friends developed the same symptoms. The diagnosis is:
Symptoms of food poisoning seen within 6 h are commonly due to:
The poison commonly detected in exhumed bodies is:
Vitreous humor is preserved in suspected poisoning with:
In strychnos nux vomica poisoning, patient:
Food Poisoning Indian Medical PG Practice Questions and MCQs
Question 1: A child with fever with abdominal cramps & pus in stools, causative organism is ?
- A. EHEC
- B. ETEC
- C. EAEC (Correct Answer)
- D. EPEC
Explanation: ***EAEC (Enteroaggregative E. coli)*** - Among the E. coli strains listed, EAEC is the answer for this question, though **this is an atypical presentation**. - EAEC classically causes **persistent watery diarrhea** (>14 days) in children, often with **low-grade fever** and **abdominal pain**. - While EAEC primarily causes non-bloody diarrhea, it can occasionally produce **mucoid stools** with inflammatory cells due to mucosal inflammation from biofilm formation. - **Note:** The classic organism for fever + cramps + pus in stools would be **Shigella**, **Campylobacter**, or **EIEC (Enteroinvasive E. coli)** - not listed here. *EHEC (Enterohemorrhagic E. coli)* - EHEC (O157:H7) causes **hemorrhagic colitis** with bloody diarrhea due to **Shiga toxins**. - Can lead to **hemolytic uremic syndrome (HUS)** in children. - Characterized by **blood** rather than pus in stools, distinguishing it from typical dysentery. *ETEC (Enterotoxigenic E. coli)* - Most common cause of **traveler's diarrhea** and watery diarrhea in developing countries. - Produces **heat-labile (LT)** and **heat-stable (ST)** enterotoxins causing secretory diarrhea. - Results in profuse **watery stools without inflammation, blood, or pus**. *EPEC (Enteropathogenic E. coli)* - Leading cause of infantile diarrhea in developing countries. - Causes **attaching and effacing** lesions on intestinal mucosa. - Results in **watery diarrhea without significant inflammatory cells or pus** in stools.
Question 2: Food poisoning with incubation period of 1-6 hours is most probably caused by
- A. H. pylori
- B. Staphylococcus aureus (Correct Answer)
- C. Salmonella typhi
- D. Streptococcus viridans
Explanation: ***Staphylococcus aureus*** - *Staphylococcus aureus* produces **toxins** that cause rapid-onset food poisoning, typically within **1-6 hours**, due to preformed toxin ingestion. - Symptoms include **nausea, vomiting, abdominal cramps**, and sometimes diarrhea, as the toxin directly irritates the gastrointestinal lining. *H. pylori* - *Helicobacter pylori* is associated with chronic conditions like **gastritis** and **peptic ulcers**, not acute food poisoning with a short incubation period. - Its effects develop over weeks to months, involving colonization of the stomach lining. *Salmonella typhi* - *Salmonella typhi* causes **typhoid fever**, which has a much longer incubation period, ranging from **6 to 30 days**. - It leads to systemic illness with fever, headache, and abdominal pain, rather than acute emetic symptoms. *Streptococcus viridans* - **Viridans streptococci** are normal inhabitants of the oral cavity and are primarily associated with conditions like **infective endocarditis** following dental procedures. - They are not typically a cause of food poisoning with a rapid incubation period.
Question 3: A patient presents with a history of pastry intake causing food poisoning. What is the most likely causative agent?
- A. Verotoxin-producing E. coli
- B. Bacillus cereus
- C. Staphylococcus aureus (Correct Answer)
- D. Enteroinvasive E. coli (EIEC)
Explanation: ***Staphylococcus aureus*** - *S. aureus* is a common cause of food poisoning linked to **creamy foods** like pastries, salads, and custards, as it produces **heat-stable enterotoxins** when allowed to proliferate. - The symptoms, typically rapid onset **nausea, vomiting**, and abdominal cramps, occur because of the **preformed toxins** in the food, not necessarily active infection. *Verotoxin-producing E. coli* - This strain, often **E. coli O157:H7**, is primarily associated with **undercooked beef** or contaminated produce, and typically causes **bloody diarrhea** and can lead to hemolytic uremic syndrome (HUS). - Its mechanism involves **verotoxins** directly damaging intestinal cells and blood vessels, which is different from the rapid, emetic-focused symptoms of *S. aureus* food poisoning. *Bacillus cereus* - *B. cereus* causes two main types of food poisoning: **emetic (vomiting)**, typically from **reheated rice**, and **diarrheal**, from meat products or vegetables. - While the emetic form can cause vomiting, it is most strongly associated with **rice dishes** and usually has a shorter incubation period than the diarrheal form, making *Staphylococcus aureus* a more classic cause for pastry-related outbreaks. *Enteroinvasive E. coli (EIEC)* - EIEC causes a disease similar to **shigellosis**, involving direct invasion of intestinal epithelial cells, leading to **bloody diarrhea** and fever. - It is typically spread through contaminated food and water and not specifically linked to pastry intake or characterized by the rapid onset emetic symptoms seen with preformed toxins.
Question 4: An individual who runs a methanol liquor racket and diverts the effluent into a pond which is used by people. He is punishable under ___ IPC:-
- A. 304 A
- B. 176
- C. 320
- D. 284 (Correct Answer)
Explanation: ***284*** - **Section 284 of the IPC** specifically deals with negligent conduct with respect to **poisonous substances**. - Diverting poisonous methanol effluent into a public pond constitutes such a **negligent act endangering human life**. *304 A* - **Section 304A IPC** deals with **causing death by negligence**. - While death might occur, the primary offense here is the negligent handling of a poisonous substance, which Section 284 more directly addresses even if death has not yet occurred. *176* - **Section 176 IPC** pertains to **omission to give notice or information to a public servant by a person legally bound to do so**. - This section is irrelevant to the act of diverting poisonous effluent into a pond, as it concerns non-reporting rather than causing harm through dangerous actions. *320* - **Section 320 IPC** defines **grievous hurt**. - While consuming the poisoned water could lead to grievous hurt, Section 284 addresses the negligent act of making the poisonous substance accessible, which is the immediate crime of concern here.
Question 5: A 34-year-old woman is seen in the emergency department. About 5 hours previously, she began to have nausea, vomiting, abdominal cramps, and diarrhea. She then developed double vision, which prompted her to ask her husband to bring her to the emergency department. When she is asked to go into the examining room, she stumbles. When she tries to answer questions, her voice sounds odd and she seems to mumble. Physical examination demonstrates a dry mouth, drooping eyelids, markedly diminished pupillary light reflex, a flaccid facial expression, and difficulty in opening her mouth. Within an hour, her condition has markedly deteriorated. She can no longer stand and is intubated because of difficulty breathing. Which of the following microbial species is MOST likely to have caused her condition?
- A. Clostridium ramosum
- B. Clostridium perfringens
- C. Clostridium septicum
- D. Clostridium botulinum (Correct Answer)
Explanation: ***Clostridium botulinum*** - The rapid onset of **nausea, vomiting, abdominal cramps, and diarrhea** followed by neurological symptoms like **double vision, stumbling, slurred speech (dysarthria), dry mouth, drooping eyelids (ptosis), diminished pupillary light reflex, and progressive muscle weakness** (leading to inability to stand and respiratory failure) is characteristic of **botulism**. - **Botulinum toxin**, produced by *Clostridium botulinum*, is a potent neurotoxin that inhibits acetylcholine release at the neuromuscular junction, causing a **flaccid paralysis** that can rapidly progress to respiratory paralysis. *Clostridium ramosum* - This species is an infrequent cause of **bacteremia and localized infections**, particularly in immunocompromised individuals. - It does not typically produce neurotoxins that lead to the rapid onset of severe neurological symptoms and flaccid paralysis seen in the patient. *Clostridium perfringens* - *Clostridium perfringens* is a common cause of **food poisoning** (characterized by nausea, vomiting, and diarrhea) and **gas gangrene**. - While it causes gastrointestinal symptoms, it does not produce neurotoxins that result in oculomotor dysfunction, dysphagia, or widespread flaccid paralysis. *Clostridium septicum* - *Clostridium septicum* is primarily associated with **gas gangrene** and **severe systemic infections**, often in patients with underlying malignancies. - It does not cause the specific neurological symptoms, particularly the descending flaccid paralysis, observed in this clinical presentation.
Question 6: A 22-year-old male had an outing with his friends and developed fever of 38.5degC, abdominal pain, diarrhea and vomiting after eating chicken salad 24 h back. Two of his friends developed the same symptoms. The diagnosis is:
- A. Staphylococcus aureus poisoning
- B. Bacillus cereus poisoning
- C. Salmonella enteritis poisoning (Correct Answer)
- D. Vibrio cholera poisoning
Explanation: Salmonella enteritis poisoning - The symptoms of fever, abdominal pain, diarrhea, and vomiting developing about 24 hours after consuming chicken salad (a common source of Salmonella) are highly characteristic of Salmonella enteritis [2], [4]. - The involvement of multiple individuals (two friends developed the same symptoms) points to a common source foodborne illness, consistent with Salmonella [4]. Staphylococcus aureus poisoning - This typically has a much shorter incubation period (1-6 hours) and is characterized by abrupt onset of severe nausea, vomiting, and abdominal cramps, often without fever [2]. - While S. aureus is a common cause of food poisoning, the 24-hour incubation period and presence of fever make it less likely in this case [4]. Bacillus cereus poisoning - This typically presents with two forms: an emetic type (short incubation, associated with rice) and a diarrheal type (longer incubation, but severe vomiting is less prominent and fever is usually absent) [1]. - The 24-hour incubation could fit the diarrheal type, but the combination of prominent vomiting and fever points away from classic B. cereus food poisoning [1]. Vibrio cholera poisoning - Cholera is characterized by profuse, watery diarrhea ("rice-water stools") and rapid dehydration, often without significant fever or initial vomiting, especially of this severity [3]. - It usually has an incubation period of a few hours to 5 days, but the symptoms described are more consistent with typical bacterial food poisoning rather than cholera [4].
Question 7: Symptoms of food poisoning seen within 6 h are commonly due to:
- A. Shigella
- B. Bacillus cereus
- C. Staphylococcus aureus (Correct Answer)
- D. Salmonella
Explanation: ***Staphylococcus aureus*** - Food poisoning due to *Staphylococcus aureus* is caused by preformed **enterotoxins** in the food, leading to rapid onset of symptoms, typically within 1-6 hours. - Common symptoms include **nausea**, **vomiting**, **abdominal cramps**, and **diarrhea**, often appearing abruptly and resolving within 24-48 hours. *Shigella* - *Shigella* infections typically cause symptoms after an **incubation period of 1-7 days**, which is much longer than the 6-hour window. - It is characterized by **dysentery** (bloody and mucoid stools), fever, and severe abdominal cramps, resulting from direct invasion of the intestinal mucosa. *Bacillus cereus* - *Bacillus cereus* can cause two types of food poisoning: diarrheal (onset 6-15 hours) and emetic (onset 0.5-6 hours). While the emetic form can occur within 6 hours, it is more specifically associated with contaminated **rice products** and prominent vomiting. - The emetic type is due to a **preformed toxin (cereulide)**, but *S. aureus* is a more common and general cause of rapid-onset food poisoning across various food types. *Salmonella* - Food poisoning from *Salmonella* typically has an **incubation period of 6 hours to 6 days**, usually 12-72 hours. - Symptoms include **fever**, diarrhea (which can be bloody), abdominal pain, nausea, and vomiting, and are due to bacterial invasion rather than preformed toxin.
Question 8: The poison commonly detected in exhumed bodies is:
- A. Lead
- B. Mercury
- C. Arsenic (Correct Answer)
- D. Cadmium
Explanation: ***Arsenic*** - **Arsenic** is the most common poison detected in exhumed bodies due to its exceptional **stability** and **resistance to degradation** in decomposing tissues. - It readily binds to **keratin-rich tissues** like hair and nails, making it detectable even after long periods (years to decades). - Known as a "**persistent poison**" in forensic medicine due to its ability to resist putrefaction and remain in tissues indefinitely. *Cadmium* - While **cadmium** is a toxic heavy metal, it is not as frequently detected in exhumed bodies as arsenic due to differing toxicokinetics and post-mortem stability. - Cadmium poisoning often involves **renal and pulmonary toxicity**, and its detection post-mortem might be more challenging after significant decomposition. *Mercury* - **Mercury** can be toxic and persist in some tissues, but its detection in exhumed bodies is less common than arsenic due to its different **metabolic pathways** and **degradation patterns**. - **Elemental mercury** is poorly absorbed, and other forms like **methylmercury** can be found, but their post-mortem stability does not match arsenic's. *Lead* - **Lead** is a heavy metal that causes chronic toxicity and can be detected in bones for extended periods. However, its overall detection rate in exhumed bodies for acute poisoning is typically lower than arsenic. - Lead's clinical presentation often includes **neurological, gastrointestinal, and hematological symptoms**, but its presence in various tissues diminishes over time compared to arsenic's unique persistence.
Question 9: Vitreous humor is preserved in suspected poisoning with:
- A. Cyanide
- B. Morphine
- C. Alcohol (Correct Answer)
- D. Carbon monoxide
Explanation: ***Alcohol*** - **Vitreous humor** is an ideal sample for postmortem alcohol analysis due to its **sequestration** from other body fluids, which minimizes postmortem production or degradation of alcohol. - Its **avascular nature** and **slow diffusion** rates ensure that the alcohol concentration in the vitreous humor closely reflects the ante-mortem blood alcohol concentration. *Cyanide* - Sampling **vitreous humor** is generally not the primary choice for detecting cyanide because cyanide is rapidly absorbed and metabolized, making its detection more reliable in other tissues. - Cyanide can degrade in biological samples, and its concentration in the vitreous humor may not accurately reflect the lethal dose or recent exposure. *Morphine* - While **vitreous humor** can be used for opiate detection, **blood and urine** are generally preferred for initial screening and quantitative analysis of morphine. - Morphine undergoes metabolism during its elimination, and its distribution into the vitreous humor might not always accurately reflect the **pharmacodynamics** or precise time of exposure compared to blood. *Carbon monoxide* - **Carbon monoxide (CO) poisoning** is primarily diagnosed by measuring **carboxyhemoglobin levels** in blood, as CO binds avidly to hemoglobin. - The vitreous humor is not a suitable sample for detecting carbon monoxide or carboxyhemoglobin as it lacks red blood cells and hemoglobin, which are the targets of CO toxicity.
Question 10: In strychnos nux vomica poisoning, patient:
- A. Remains conscious throughout. (Correct Answer)
- B. Develops respiratory failure at end stage
- C. Develops immediate paralysis
- D. Experiences mild drowsiness in 1 h or so
Explanation: ***Remains conscious throughout.*** - Patients poisoned with **strychnine** (from *Strychnos nux-vomica*) maintain **full consciousness** throughout the entire episode, including during the characteristic **tetanic spasms** and convulsions. - This preservation of consciousness is a **pathognomonic feature** of strychnine poisoning and makes the experience particularly distressing as patients are fully aware of the severe muscle contractions and pain. - This distinguishes strychnine poisoning from many other toxicological emergencies where altered consciousness is common. *Develops respiratory failure at end stage* - While **respiratory failure** does occur in severe strychnine poisoning and is indeed the **usual cause of death**, it is a consequence rather than a distinguishing clinical feature. - Death occurs due to **asphyxia** from sustained tetanic spasm of respiratory muscles or from **exhaustion** following repeated convulsions. - However, maintaining consciousness throughout (Option A) is the more characteristic and diagnostically significant feature. *Develops immediate paralysis* - Strychnine acts as a **competitive antagonist of glycine** at inhibitory receptors in the spinal cord and brainstem, blocking inhibitory neurotransmission. - This leads to **unopposed excitation**, causing **exaggerated reflexes**, **muscle rigidity**, and **tetanic spasms** - the opposite of paralysis. - The primary clinical manifestation is **intense muscle spasms** (especially extensor muscles), resulting in **opisthotonos** and **risus sardonicus**. *Experiences mild drowsiness in 1 h or so* - Strychnine poisoning has a **rapid onset** of severe symptoms, typically within **15-30 minutes** of ingestion. - Mild drowsiness is not characteristic; instead, patients are **hyperalert** and fully conscious, experiencing **intense distress** and pain. - The clinical picture includes **muscle stiffness**, **heightened sensory perception**, and **violent spasms** triggered by minor stimuli (sound, light, touch).
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