Non-Communicable Diseases — MCQs

Non-Communicable Diseases Indian Medical PG Practice Questions and MCQs

Question 81: What is true about measles?

A. Koplik spots appear in the prodromal stage. (Correct Answer)
B. Fever stops after the onset of rash.
C. The vaccine is given at 9 months.
D. It is not diagnosed when coryza and rhinitis are absent.

Explanation: **Explanation:** **1. Why Option A is correct:** Measles (Rubeola) follows a distinct clinical course. The **prodromal stage** (lasting 3–4 days) is characterized by the "3 Cs": Cough, Coryza, and Conjunctivitis, along with high fever. **Koplik spots**—small, bluish-white grains of sand on an erythematous base—appear on the buccal mucosa opposite the lower second molars during this stage. They are pathognomonic for measles and typically disappear shortly after the rash appears. **2. Why other options are incorrect:** * **Option B:** In measles, the fever typically **peaks** (reaches its maximum) with the onset of the rash. It does not stop; rather, it remains high for 2–3 days after the rash appears before subsiding. * **Option C:** Under the current **Universal Immunization Programme (UIP)** in India, the first dose of the Measles-Rubella (MR) vaccine is given at **9 completed months** (up to 12 months). While traditionally "9 months" is the answer, in the context of NEET-PG, Option A is a more definitive clinical "truth" regarding the disease pathology itself. * **Option D:** While coryza and rhinitis are classic symptoms, the clinical diagnosis is primarily based on the characteristic maculopapular rash and fever. The absence of one prodromal symptom does not rule out the diagnosis, especially during an outbreak. **High-Yield Clinical Pearls for NEET-PG:** * **Incubation Period:** 10–14 days. * **Period of Communicability:** 4 days before to 4 days after the appearance of the rash. * **Rash Pattern:** Starts behind the ears (retro-auricular), spreads downwards to the face, trunk, and extremities (cephalocaudal progression). * **Vitamin A:** Supplementation is mandatory in measles management to prevent complications like blindness and reduce mortality. * **Secondary Attack Rate (SAR):** >90% (highly infectious).

Question 82: Transovarian transmission is a feature of which of the following diseases?

A. Scrub typhus (Correct Answer)
B. Epidemic typhus
C. Endemic typhus
D. Trench fever

Explanation: **Explanation:** **1. Why Scrub Typhus is Correct:** Scrub typhus is caused by *Orientia tsutsugamushi* and is transmitted by the bite of infected larval mites (chiggers) of the family Trombiculidae. A unique biological feature of this disease is **transovarian transmission**, where the pathogen is passed from the adult female mite to her eggs. This ensures the next generation of larvae is born infected. Additionally, it exhibits **trans-stadial transmission** (pathogen persists through life stages: larva to nymph to adult). Since only the larval stage (chigger) feeds on humans, these mechanisms are essential for the pathogen's survival in the mite population. **2. Why the Other Options are Incorrect:** * **Epidemic Typhus (*R. prowazekii*):** Transmitted by the human body louse. The louse dies from the infection and does not pass the bacteria to its offspring. * **Endemic Typhus (*R. typhi*):** Transmitted by the rat flea (*Xenopsylla cheopis*). While it shows trans-stadial transmission, transovarian transmission is not a primary feature. * **Trench Fever (*Bartonella quintana*):** Also transmitted by the human body louse; no transovarian transmission occurs. **3. High-Yield Clinical Pearls for NEET-PG:** * **Vector:** Chigger (larval mite). * **Pathognomonic Sign:** **Eschar** (a painless, black crusty lesion at the bite site). * **Diagnosis:** Weil-Felix test (Positive for **OX-K** strain) or IgM ELISA (Gold Standard). * **Drug of Choice:** Doxycycline (Azithromycin is preferred in pregnancy). * **Reservoir:** The mite itself acts as both vector and reservoir due to transovarian transmission.

Question 83: All of the following are commonly used Filarial indices except?

A. Microfilaria rate
B. Filarial disease rate (Correct Answer)
C. Filarial epidemicity rate
D. Mosquito infection rate

Explanation: To assess the burden of Lymphatic Filariasis in a community, specific epidemiological indices are utilized. The correct answer is **B. Filarial disease rate**, as it is not a standard index used in public health surveillance for filariasis. ### **Explanation of Indices** The standard indices used to measure filariasis in a population are: 1. **Microfilaria (mf) Rate:** The percentage of persons showing microfilariae in their peripheral blood (usually collected at night). It is the most common index of **host infection**. 2. **Microfilaria Density:** The average number of microfilariae per unit volume of blood. 3. **Filarial Endemicity Rate (Option C):** This is the sum of the **Microfilaria rate** and the **Elephantiasis rate** (clinical disease rate). It provides a composite picture of the total infection and morbidity in an area. 4. **Mosquito Infection Rate (Option D):** An entomological index measuring the percentage of mosquitoes found positive for any stage of the filarial parasite upon dissection. ### **Why Option B is the Correct Answer** While "Elephantiasis rate" is a component of the Endemicity rate, the term **"Filarial disease rate"** is not a standard epidemiological term used in the National Vector Borne Disease Control Programme (NVBDCP) or WHO guidelines. Standard reporting focuses on infection (mf rate) or total endemicity. ### **High-Yield Facts for NEET-PG** * **Vector:** *Culex quinquefasciatus* is the most common vector for *Wuchereria bancrofti* in India. * **Drug of Choice:** **Diethylcarbamazine (DEC)** is the DOC. However, in Mass Drug Administration (MDA), a combination of **DEC + Albendazole** (or Ivermectin in certain areas) is used. * **MDA Goal:** The aim is to cover the entire at-risk population (excluding children <2 years, pregnant women, and the very ill) once a year for 5 consecutive years to interrupt transmission. * **Lymphedema Management:** Focuses on "Morbidity Management and Disability Prevention" (MMDP) through local hygiene and foot care.

Question 84: Which of the following is a ratio?

A. Infant Mortality Rate (IMR)
B. Maternal Mortality Ratio (MMR) (Correct Answer)
C. Prevalence
D. Incidence

Explanation: In epidemiology, understanding the mathematical tools used to measure health events is crucial for NEET-PG. **1. Why Maternal Mortality Ratio (MMR) is the Correct Answer:** A **Ratio** expresses a relationship between two independent quantities where the numerator is **not** a part of the denominator ($x/y$). * **MMR Formula:** (Number of maternal deaths / Number of **live births**) × 100,000. * Since "maternal deaths" are not a subset of "live births," they are two distinct entities, making it a true ratio. **2. Why the Other Options are Incorrect:** * **Infant Mortality Rate (IMR):** Despite its name, IMR is technically a **probability** (often treated as a rate in public health). It measures the risk of death. The numerator (deaths under 1 year) is derived from the denominator (live births in the same year). * **Prevalence:** This is a **Proportion**. It measures the total number of cases (old + new) existing in a population at a specific time. The numerator is always included in the denominator ($x / x+y$), usually expressed as a percentage. * **Incidence:** This is a **Rate**. It measures the occurrence of *new* cases in a population-at-risk over a specific period. It incorporates "time" into the denominator (person-years). **Clinical Pearls & High-Yield Facts:** * **The "Rate" Exception:** MMR is the only "Mortality Rate" that is actually a **Ratio**. * **Case Fatality Rate (CFR):** Despite the name, CFR is a **Proportion**, as it measures deaths among those who have the disease. * **Denominator of MMR:** Always remember it is per **100,000 live births**, whereas IMR is per **1,000 live births**. * **Prevalence = Incidence × Duration ($P = I \times D$):** A classic formula for NEET-PG numericals.

Question 85: What is the recommended prophylaxis for cholera?

A. Doxycycline 300mg once daily (Correct Answer)
B. Cephalosporin
C. Streptomycin
D. Cotrimoxazole

Explanation: **Explanation:** The correct answer is **Doxycycline 300mg once daily**. **1. Why Doxycycline is Correct:** In the management of cholera, chemoprophylaxis is recommended only for **household contacts** (close contacts) of a confirmed case. **Doxycycline** is the drug of choice for adults because it effectively reduces the duration of diarrhea and the excretion of *Vibrio cholerae*. The standard prophylactic dose for an adult is a **single dose of 300 mg**. It works by inhibiting bacterial protein synthesis (30S subunit). **2. Why Other Options are Incorrect:** * **Cephalosporins (Option B):** While some third-generation cephalosporins have activity against Gram-negative bacteria, they are not the standard of care for cholera prophylaxis and are less effective than tetracyclines in reducing stool volume. * **Streptomycin (Option C):** This is an aminoglycoside primarily used for Tuberculosis and Plague. It is not used for cholera due to poor oral absorption and lack of efficacy against *V. cholerae*. * **Cotrimoxazole (Option D):** Previously used as an alternative, but widespread resistance has made it less reliable. It is currently reserved for children or pregnant women only if other first-line drugs are unavailable. **3. High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC) for Treatment:** Doxycycline (Single dose 300mg). * **DOC for Children/Pregnant Women:** Azithromycin (Single dose 500mg or 20mg/kg). * **Mass Prophylaxis:** It is **never recommended** for cholera as it does not prevent the spread of the epidemic and promotes antibiotic resistance. * **Most Important Treatment:** Rehydration (ORS and IV fluids like Ringer’s Lactate) remains the cornerstone of therapy; antibiotics are secondary. * **Vaccines:** Oral Cholera Vaccines (OCV) like **Dukoral** and **Shanchol** are used for prevention in endemic areas.

Question 86: Which of the following vaccines, if contaminated, can cause Toxic Shock Syndrome (TSS)?

A. Measles vaccine (Correct Answer)
B. DPT
C. Hepatitis B
D. Typhoral

Explanation: **Explanation:** **Toxic Shock Syndrome (TSS)** following immunization is a severe, life-threatening condition primarily caused by the contamination of multi-dose vaccine vials with **Staphylococcus aureus**. 1. **Why Measles Vaccine is the Correct Answer:** The Measles vaccine is a **live-attenuated, lyophilized (freeze-dried)** vaccine that requires reconstitution with a diluent. Once reconstituted, the vaccine does not contain any preservative (like Thiomersal). If the vial is kept at room temperature for several hours, it becomes an ideal culture medium for *Staphylococcus aureus*. If contaminated needles are used or if the reconstituted vial is used beyond the recommended 4–6 hours, the bacteria multiply and produce exotoxins, leading to TSS in the vaccine recipients. 2. **Analysis of Incorrect Options:** * **B. DPT:** This is a liquid vaccine that contains **Thiomersal** as a preservative, which inhibits bacterial growth, making TSS highly unlikely. * **C. Hepatitis B:** This is also a liquid recombinant vaccine containing preservatives; it does not require reconstitution, reducing the risk of contamination during handling. * **D. Typhoral:** This is an oral live-attenuated vaccine (Ty21a). Since it is administered via the gastrointestinal route and not parenterally, it does not cause systemic Toxic Shock Syndrome associated with injection site contamination. **High-Yield Clinical Pearls for NEET-PG:** * **The 4-Hour Rule:** According to the Open Vial Policy, reconstituted vaccines like Measles, BCG, and JE must be discarded after **4 hours** (or at the end of the session) to prevent TSS. * **Clinical Presentation:** TSS post-measles vaccination typically presents within a few hours with high fever, vomiting, watery diarrhea, and rapid progression to hypotension/shock. * **Most Common Organism:** *Staphylococcus aureus* is the most common cause of vaccine-associated TSS.

Question 87: During a cholera epidemic, what is the first step to be taken?

A. Ensure a safe water supply and sanitation (Correct Answer)
B. Administer cholera vaccination to all individuals
C. Provide primary chemoprophylaxis
D. Treat everyone with tetracycline

Explanation: **Explanation:** In the management of a cholera epidemic, the immediate priority is to break the chain of transmission. Since *Vibrio cholerae* is primarily transmitted via the fecal-oral route through contaminated water and food, **ensuring a safe water supply and sanitation** is the most effective first step to prevent further spread. This involves chlorination of water sources, health education regarding hand hygiene, and proper disposal of excreta. **Analysis of Options:** * **Option B (Vaccination):** While oral cholera vaccines (OCV) are used for prevention in endemic areas, they are not the "first step" during an active epidemic. They take time to provide immunity and do not address the immediate source of infection. * **Option C & D (Chemoprophylaxis/Tetracycline):** Mass chemoprophylaxis (treating everyone) is **not recommended** by the WHO. It is ineffective in stopping an epidemic, leads to antibiotic resistance, and provides a false sense of security. Selective chemoprophylaxis is only considered for close household contacts. **NEET-PG High-Yield Pearls:** * **Gold Standard Treatment:** Rehydration (ORS and IV fluids) is the mainstay of clinical management to reduce mortality. * **Drug of Choice:** **Doxycycline** (single dose) is the drug of choice for treating cases and for selective chemoprophylaxis. * **Indicator of Water Safety:** For drinking water during an epidemic, the **residual chlorine** level should be **0.5 mg/L**. * **Best Method of Water Disinfection:** Chlorination is the most practical and effective method during outbreaks.

Question 88: Which component of cigarette smoke is primarily responsible for Coronary Artery Disease (CAD)?

A. Nicotine
B. Tar
C. Polycyclic aromatic hydrocarbons
D. Benzene (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Benzene** **Medical Concept:** While cigarette smoke contains over 7,000 chemicals, **Benzene** is identified as a major contributor to cardiovascular morbidity. Benzene exposure leads to oxidative stress and systemic inflammation, which are key drivers of **atherosclerosis**. It promotes the formation of fatty streaks in the arterial walls and triggers endothelial dysfunction, directly increasing the risk of Coronary Artery Disease (CAD). In the context of public health and toxicology, benzene is a potent cardiotoxin and carcinogen. **Analysis of Incorrect Options:** * **A. Nicotine:** While nicotine is the primary **addictive** substance and causes acute hemodynamic changes (increased heart rate and blood pressure) via catecholamine release, it is generally considered less significant than benzene or carbon monoxide in the long-term pathogenesis of atherosclerosis. * **B. Tar:** Tar is a collection of solid particles that settle in the airways. It is primarily responsible for **lung cancer** and chronic obstructive pulmonary disease (COPD) rather than direct cardiovascular damage. * **C. Polycyclic Aromatic Hydrocarbons (PAHs):** These are potent **carcinogens** (e.g., Benzopyrene) primarily linked to various cancers (lung, skin, bladder). While they contribute to oxidative stress, they are not the "primary" component cited for CAD compared to the systemic inflammatory effects of benzene. **High-Yield Clinical Pearls for NEET-PG:** * **Carbon Monoxide (CO):** Another major culprit for CAD in smokers; it binds to hemoglobin (forming Carboxyhemoglobin), reducing oxygen delivery to the myocardium and worsening ischemia. * **Smoking & Lipid Profile:** Smoking lowers HDL ("good" cholesterol) and increases VLDL and LDL, further accelerating CAD. * **Reversibility:** The risk of CAD decreases by **50% within one year** of quitting smoking, making it the most modifiable risk factor for heart disease.

Question 89: Human filariasis is caused by which of the following organisms?

A. Loa-loa
B. Onchocerca Volvulus
C. Wuchereria Bancrofti (Correct Answer)
D. Brugia Malayi

Explanation: **Explanation:** **Wuchereria bancrofti** is the correct answer because it is the primary causative agent of **Lymphatic Filariasis**, accounting for approximately 90% of cases globally and the vast majority in India. The disease is characterized by the obstruction of lymphatic vessels by adult worms, leading to lymphedema and elephantiasis. In India, the primary vector for *W. bancrofti* is the *Culex quinquefasciatus* mosquito. **Analysis of Incorrect Options:** * **Loa-loa:** Causes "African Eye Worm" or Loiasis. It is characterized by Calabar swellings and the migration of adult worms across the subconjunctiva of the eye, rather than classic lymphatic obstruction. * **Onchocerca volvulus:** Causes "River Blindness" (Onchocerciasis). It is transmitted by the Blackfly (*Simulium*) and primarily affects the skin and eyes, leading to severe itching and visual impairment. * **Brugia malayi:** While it also causes lymphatic filariasis, it is less common than *W. bancrofti*. In India, it is restricted to specific pockets (e.g., Kerala). It typically causes lymphedema below the knee and rarely involves the genitals. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Diethylcarbamazine (DEC) is the standard treatment. However, in Global Elimination programs (GPELF), a triple drug therapy (**IDA**: Ivermectin, DEC, and Albendazole) is now recommended. * **Nocturnal Periodicity:** Microfilariae of *W. bancrofti* usually circulate in peripheral blood at night (10 PM – 2 AM), coinciding with the biting habits of the *Culex* mosquito. * **Diagnosis:** The "Gold Standard" is the demonstration of microfilariae in a peripheral blood smear. * **National Target:** India aims for the **elimination** of Lymphatic Filariasis (defined as <1% microfilaria rate in all sentinel sites).

Question 90: Scrub typhus is caused by which organism?

A. Rickettsia tsutsugamushi (Correct Answer)
B. Rickettsia typhi
C. Rickettsia akari
D. Rickettsia conorii

Explanation: **Explanation:** Scrub typhus is a zoonotic rickettsial infection caused by **Orientia tsutsugamushi** (formerly known as **Rickettsia tsutsugamushi**). It is transmitted to humans through the bite of infected larval mites (chiggers) of the genus *Leptotrombidium*. **Analysis of Options:** * **Option A (Correct):** *Rickettsia tsutsugamushi* is the causative agent. It is an obligate intracellular bacterium. The hallmark clinical sign is an **eschar** (a painless, black crusty sore) at the site of the mite bite. * **Option B (Incorrect):** *Rickettsia typhi* causes **Endemic (Murine) Typhus**, which is transmitted by the rat flea (*Xenopsylla cheopis*). * **Option C (Incorrect):** *Rickettsia akari* causes **Rickettsialpox**, transmitted by the house mouse mite (*Liponyssoides sanguineus*). * **Option D (Incorrect):** *Rickettsia conorii* causes **Indian Tick Typhus** (Boutonneuse fever), transmitted by the dog tick (*Rhipicephalus sanguineus*). **High-Yield Clinical Pearls for NEET-PG:** * **Vector:** Larval mite (Chigger). * **Reservoir:** Trombiculid mites (undergo transovarial transmission). * **Diagnosis:** The **Weil-Felix test** shows agglutination with **OX-K** strain (negative for OX-19 and OX-2). However, the gold standard is the Indirect Immunofluorescence Assay (IFA). * **Drug of Choice:** **Doxycycline** is the first-line treatment for all age groups. Azithromycin is an alternative, especially in pregnancy. * **Geography:** Part of the "Tsutsugamushi Triangle" (extending from Japan to Australia to India/Pakistan). In India, it is a significant cause of "Acute Undifferentiated Febrile Illness."

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