Non-Communicable Diseases — MCQs

Non-Communicable Diseases Indian Medical PG Practice Questions and MCQs

Question 361: What is the annual growth rate in moderate growth?

A. <0.5
B. 0.5-1.0 (Correct Answer)
C. 1.0-1.5
D. 1.5-2.0

Explanation: ### Explanation The annual growth rate of a population is a critical demographic indicator used in Community Medicine to monitor population dynamics and plan health resources. According to the classification of population growth rates, a **moderate growth rate** is defined as an annual increase between **0.5% and 1.0%**. #### Analysis of Options: * **Option B (0.5-1.0) - Correct:** This range represents moderate growth. At this rate, a population is increasing steadily but not explosively. * **Option A (<0.5):** This is classified as **Low growth**. Many developed nations fall into this category, sometimes even reaching "Zero population growth" or negative growth. * **Option C (1.0-1.5):** This range is generally classified as **High growth**. * **Option D (1.5-2.0):** This represents **Very High growth**. Rates above 2.0% are often referred to as "Explosive growth." #### High-Yield Clinical Pearls for NEET-PG: * **Demographic Trap:** A situation where a country's population growth rate is high while its economic growth is low, preventing a transition to the next demographic stage. * **Rule of 70:** To calculate the **doubling time** of a population, divide 70 by the annual growth rate (e.g., a 1% growth rate doubles the population in 70 years). * **India’s Status:** India is currently in **Stage 3** of the Demographic Transition (Late Expanding), characterized by a declining birth rate and a low death rate, leading to a gradual slowdown in the growth rate. * **Net Reproduction Rate (NRR):** The target for population stabilization is an **NRR of 1**, which corresponds to a Replacement Level Fertility (TFR of 2.1).

Question 362: Infectivity of an organism is measured by:

A. Incidence rate (Correct Answer)
B. Prevalence rate
C. Secondary attack rate
D. Case fatality rate

Explanation: ### Explanation **1. Why the Correct Answer is Right:** **Incidence rate** measures the frequency of occurrence of new cases in a population during a specified period. In the context of infectious diseases, it is the primary indicator of the **infectivity** of an organism (the ability of an agent to enter, survive, and multiply in a host). A high incidence rate directly reflects the speed and efficiency with which an organism spreads and establishes new infections within a susceptible population. **2. Analysis of Incorrect Options:** * **Prevalence rate:** This measures the total number of existing cases (old + new) at a given point in time. It is influenced by both the incidence and the duration of the disease, making it a measure of **disease burden**, not infectivity. * **Secondary Attack Rate (SAR):** While often confused with infectivity, SAR specifically measures the **communicability** or "contagiousness" of a disease within a closed group (e.g., a household) following exposure to a primary case. It is a subset of incidence but is not the standard general measure for infectivity. * **Case Fatality Rate (CFR):** This measures the proportion of deaths among diagnosed cases. It is an indicator of the **virulence** or severity of the organism, not its ability to infect. **3. High-Yield Clinical Pearls for NEET-PG:** * **Infectivity:** Measured by Incidence Rate. * **Virulence:** Measured by Case Fatality Rate (CFR). * **Pathogenicity:** The ability to cause clinically apparent disease (Ratio of clinical cases to total infections). * **Communicability:** Measured by Secondary Attack Rate (SAR). * **Formula for SAR:** (Number of exposed persons developing disease within incubation period / Total number of susceptible contacts) × 100.

Question 363: All of the following are used to treat influenza B except?

A. Oseltamivir
B. Zanamivir
C. Peramivir
D. Ribavirin (Correct Answer)

Explanation: **Explanation:** The correct answer is **Ribavirin**. **1. Why Ribavirin is the correct answer:** Ribavirin is a broad-spectrum antiviral agent primarily used for the treatment of **Hepatitis C** (in combination with other drugs) and **Respiratory Syncytial Virus (RSV)** in children. While it has some *in vitro* activity against influenza, it is **not** clinically indicated or FDA-approved for the treatment of Influenza A or B. Its mechanism involves interfering with viral RNA synthesis, but it lacks the specificity required for effective influenza management. **2. Why the other options are incorrect:** Options A, B, and C belong to the class of **Neuraminidase Inhibitors (NAIs)**. These drugs work by inhibiting the enzyme neuraminidase, preventing the release of new viral particles from infected host cells. They are effective against **both Influenza A and B**. * **Oseltamivir (Tamiflu):** Administered orally; the most commonly used drug for prophylaxis and treatment. * **Zanamivir (Relenza):** Administered via inhalation; used in patients >7 years old. * **Peramivir (Rapivab):** Administered as a single intravenous (IV) dose; useful for patients who cannot tolerate oral or inhaled medications. **3. NEET-PG High-Yield Pearls:** * **Baloxavir Marboxil:** A newer drug for Influenza A and B that acts as a **Cap-dependent endonuclease inhibitor** (single oral dose). * **Amantadine/Rimantadine:** These are M2 ion channel blockers. They are **only** effective against Influenza A and are currently not recommended due to widespread resistance. * **Treatment Window:** For maximum efficacy, antiviral therapy should ideally be started within **48 hours** of symptom onset. * **Vaccination:** The most effective way to prevent influenza; the composition is updated annually by the WHO based on circulating strains.

Question 364: What is the causative agent and vector for epidemic typhus?

A. Rickettsia prowazekii & Louse (Correct Answer)
B. R. typhi & Mite
C. R. conorii & Tick
D. R. akari & Mite

Explanation: **Explanation:** Epidemic typhus is a severe rickettsial disease caused by **Rickettsia prowazekii**. It is transmitted to humans by the **human body louse** (*Pediculus humanus corporis*). The transmission occurs when louse feces containing the bacteria are rubbed into bite wounds or mucous membranes. This disease is historically associated with overcrowding, poverty, and famine (often called "jail fever" or "war fever"). **Analysis of Options:** * **Option A (Correct):** *R. prowazekii* is the agent for Epidemic typhus, and the Louse is the vector. * **Option B (Incorrect):** *R. typhi* causes **Endemic (Murine) typhus**, and the vector is the **Rat flea** (*Xenopsylla cheopis*). * **Option C (Incorrect):** *R. conorii* causes **Indian Tick Typhus** (Boutonneuse fever), and the vector is the **Tick**. * **Option D (Incorrect):** *R. akari* causes **Rickettsialpox**, and the vector is the **Mite** (*Liponyssoides sanguineus*). **High-Yield Clinical Pearls for NEET-PG:** 1. **Brill-Zinsser Disease:** This is a recrudescent (latent) form of epidemic typhus that occurs years after the primary infection. 2. **Weil-Felix Test:** A classic heterophile antibody test used for diagnosis. Epidemic typhus shows a positive reaction with **OX-19**. 3. **Drug of Choice:** **Doxycycline** is the gold standard treatment for all rickettsial infections. 4. **Scrub Typhus (Important Differential):** Caused by *Orientia tsutsugamushi* and transmitted by **Trombiculid mites (Chiggers)**; characterized by a pathognomonic **eschar**.

Question 365: What is the designation for the number of tubercle bacilli if the count in an AFB sample is greater than 10 per oil immersion field?

A. +
B. ++
C. +++ (Correct Answer)
D. Scanty

Explanation: ### Explanation The grading of Sputum Smear Microscopy for Acid-Fast Bacilli (AFB) is based on the **RNTCP (Revised National Tuberculosis Control Programme)** guidelines, which follow the WHO/IUALTD scale. This grading is crucial for determining the bacterial load and the infectiousness of a patient. **Why Option C is Correct:** According to the standard grading scale, a sample is designated as **3+ (+++)** when more than **10 AFB are seen per oil immersion field (OIF)** after counting at least 20 fields. This indicates a very high bacterial load. **Analysis of Incorrect Options:** * **Option A (+):** This grade is given when **10 to 99 AFB** are found per **100 oil immersion fields**. * **Option B (++):** This grade is assigned when **1 to 10 AFB** are found per **oil immersion field** (after counting 50 fields). * **Option D (Scanty):** This is used when **1 to 9 AFB** are found per **100 oil immersion fields**. In such cases, the exact number of bacilli must be recorded (e.g., "Scanty 5"). **High-Yield Clinical Pearls for NEET-PG:** * **Minimum Fields:** To declare a slide "Negative," at least **100 oil immersion fields** must be examined without finding any bacilli. * **Staining:** The most common method used is the **Ziehl-Neelsen (ZN) stain** (Hot method). * **Fluorescence Microscopy:** If using Auramine-O (Fluorescence), the grading differs because the magnification is lower (40x), allowing for a larger field of view. * **Diagnostic Shift:** Under the current **NTEP (National TB Elimination Program)**, the focus has shifted toward **NAAT (CBNAAT/Truenat)** as the initial diagnostic tool rather than just smear microscopy.

Question 366: Which marker indicates the infectivity of serum in Hepatitis B?

A. HBsAg
B. Anti-HBc
C. HBeAg (Correct Answer)
D. Anti-Hbc

Explanation: ### Explanation **Correct Option: C. HBeAg** The **Hepatitis B e-antigen (HBeAg)** is a soluble protein derived from the precore/core region of the HBV genome. It serves as a qualitative marker of **active viral replication** and high viral load. Therefore, its presence in the serum indicates that the patient is **highly infectious** and at a greater risk of transmitting the virus to others (e.g., via needle-stick injuries or vertical transmission). **Analysis of Incorrect Options:** * **A. HBsAg (Surface Antigen):** This is the first marker to appear and indicates that the person is **infected** (either acute or chronic). While it confirms the presence of the virus, it does not specifically quantify the level of infectivity or replication. * **B & D. Anti-HBc (Antibody to Core Antigen):** * **IgM anti-HBc** is the marker for **acute infection** and is the only marker present during the "window period." * **IgG anti-HBc** indicates a **past infection** (remote exposure). These antibodies do not indicate high infectivity. **High-Yield Clinical Pearls for NEET-PG:** * **Best indicator of infectivity:** HBeAg (followed by HBV-DNA levels). * **Marker of "Super-Infectivity":** HBeAg. * **Marker of Recovery/Immunity:** Anti-HBs (HBsAb). * **Window Period Marker:** IgM anti-HBc. * **Screening Marker for Blood Banks:** HBsAg. * **Low Infectivity:** Presence of **Anti-HBe** usually signifies that the viral replication has slowed down, indicating a state of low infectivity.

Question 367: Which degree of dehydration is indicated by thirst in a child with diarrhea?

A. Mild (Correct Answer)
B. Moderate
C. Severe
D. None

Explanation: ### Explanation In the clinical assessment of dehydration due to diarrhea (based on WHO and IAP guidelines), **thirst** is the earliest clinical sign of fluid deficit. **1. Why "Mild" is correct:** According to the traditional classification of dehydration: * **Mild Dehydration (3–5% fluid loss):** The body compensates for early fluid loss by stimulating the thirst center in the hypothalamus. At this stage, the child is alert but **thirsty** and eager to drink. Other signs like skin turgor and fontanelles remain mostly normal. * **Note on WHO Classification:** In the current WHO "IMNCI" classification, "Some Dehydration" (which encompasses mild-to-moderate) is characterized by a child who is "thirsty/drinks eagerly." **2. Why the other options are incorrect:** * **Moderate Dehydration (6–9%):** While the child remains thirsty, more systemic signs appear, such as sunken eyes, dry mucous membranes, and a slow return of the skin pinch (loss of turgor). * **Severe Dehydration (≥10%):** At this critical stage, the child often becomes too lethargic or unconscious to drink. Therefore, the child is **unable to drink** or drinks poorly, rather than being simply "thirsty." This is a medical emergency requiring IV fluids. **3. High-Yield Clinical Pearls for NEET-PG:** * **Earliest Sign:** Thirst is the earliest subjective sign; **tachycardia** is often the earliest objective sign of dehydration. * **Best Indicator:** The most accurate way to assess the degree of dehydration is **percentage of body weight loss**. * **Skin Pinch:** In severe dehydration, the skin pinch goes back **very slowly** (>2 seconds). * **Management:** Mild/Some dehydration is managed with **ORS (Plan B)**, while Severe dehydration requires **Ringer’s Lactate (Plan C)**.

Question 368: All statements regarding the diagnosis and classification of leprosy are true, except?

A. A 'plus 2' mean indicates the presence of 2 bacilli in 2 smears. (Correct Answer)
B. At least 7 skin smears should be examined.
C. A paucibacillary leprosy classification has a bacterial index less than 2.
D. A multibacillary leprosy classification has a bacterial index greater than or equal to 2.

Explanation: **Explanation:** The correct answer is **A**. This statement is incorrect because the **Bacterial Index (BI)** follows a logarithmic scale (Ridley’s Scale). A BI of **+2** does not mean 2 bacilli in 2 smears; rather, it indicates finding **1 to 10 bacilli per 10 high-power fields (HPF)**. The scale ranges from 0 (no bacilli in 100 HPF) to +6 (over 1000 bacilli per HPF). **Analysis of other options:** * **Option B:** In standard practice for diagnosis and research, at least **7 sites** (typically both earlobes, four skin lesions, and the nasal mucosa) should be examined to ensure an accurate representative bacterial load. * **Options C & D:** According to the WHO classification for research and the Ridley-Jopling scale, **Paucibacillary (PB)** leprosy is defined by a BI of **<2**, while **Multibacillary (MB)** leprosy is defined by a BI of **≥2** at any site. (Note: For field programs, WHO simplifies this based on lesion count: PB = 1-5 lesions; MB = >5 lesions). **High-Yield Clinical Pearls for NEET-PG:** 1. **Morphological Index (MI):** Measures the percentage of **solid-staining (viable)** bacilli. It is a better indicator of treatment response than BI. 2. **Standard MDT Duration:** PB leprosy is treated for 6 months; MB leprosy is treated for 12 months. 3. **Definitive Diagnosis:** In the field, leprosy is diagnosed by at least one of three cardinal signs: definite sensory loss, thickened nerves, or positive skin smears. 4. **Accompanied MDT:** A strategy where a full course of MDT is given to the patient on the first visit if they live in remote areas to ensure treatment completion.

Question 369: Kyanasur forest disease is transmitted by which vector?

A. Haema physalis spinigera (Correct Answer)
B. Culex vishnui
C. Aedes
D. Anopheles

Explanation: **Explanation:** **Kyasanur Forest Disease (KFD)**, also known as "Monkey Fever," is a viral hemorrhagic fever endemic to the South Indian state of Karnataka. It is caused by the Kyasanur Forest Disease Virus (KFDV), a member of the family *Flaviviridae*. **1. Why Option A is Correct:** The primary vector for KFD is the hard tick, specifically **_Haemaphysalis spinigera_**. Ticks act as both the vector and the reservoir (through trans-ovarial and trans-stadial transmission). Humans are "dead-end hosts" and usually contract the disease through a tick bite following contact with infected monkeys (Langurs and Bonnet Macaques), which act as amplifier hosts. **2. Why the Other Options are Incorrect:** * **Option B (Culex vishnui):** This is the primary vector for **Japanese Encephalitis (JE)** in India. * **Option C (Aedes):** *Aedes aegypti* and *Aedes albopictus* are the vectors for **Dengue, Chikungunya, Zika, and Yellow Fever**. * **Option D (Anopheles):** This genus is the well-known vector for **Malaria**. **3. High-Yield Clinical Pearls for NEET-PG:** * **Reservoir:** Ticks, wild rodents, and monkeys. * **Sentinel Surveillance:** Sudden deaths of monkeys in a forest area are a warning sign of an impending KFD outbreak. * **Clinical Presentation:** Characterized by sudden onset high fever, severe headache, myalgia, and hemorrhagic manifestations. A "biphasic" fever pattern is often seen. * **Prevention:** A **formalin-inactivated vaccine** is used in endemic areas (2 doses at 1-month intervals, followed by a booster at 6-9 months and then annually). * **Diagnosis:** PCR (early stage) or IgM ELISA.

Question 370: What is the concentration of sodium in reduced osmolarity ORS (in mmol/litre)?

A. 50
B. 75 (Correct Answer)
C. 65
D. 20

Explanation: **Explanation:** The World Health Organization (WHO) and UNICEF transitioned from standard ORS to **Reduced Osmolarity ORS** to minimize the risk of hypernatremia and reduce the need for unscheduled IV fluids. The correct concentration of **Sodium in reduced osmolarity ORS is 75 mmol/L.** **Why 75 mmol/L is correct:** The total osmolarity of this formulation is **245 mOsm/L**. A sodium concentration of 75 mmol/L, paired with a glucose concentration of 75 mmol/L (1:1 molar ratio), optimizes the sodium-glucose cotransport mechanism in the small intestine, ensuring maximum water absorption while reducing stool output and vomiting compared to the older formula. **Analysis of Incorrect Options:** * **A (50 mmol/L):** This is too low for standard rehydration. However, "ReSoMal" (Rehydration Solution for Malnutrition) used in severe acute malnutrition contains 45–50 mmol/L of sodium. * **C (65 mmol/L):** This is the concentration of **Chloride** in the reduced osmolarity ORS, not sodium. * **D (20 mmol/L):** This is the concentration of **Potassium** in the reduced osmolarity ORS. **High-Yield Facts for NEET-PG:** * **Composition of Reduced Osmolarity ORS (per litre):** * Sodium Chloride: 2.6 g * Glucose (anhydrous): 13.5 g * Potassium Chloride: 1.5 g * Trisodium Citrate: 2.9 g * **Molar Concentrations (mmol/L):** Sodium (75), Glucose (75), Chloride (65), Potassium (20), Citrate (10). **Total Osmolarity = 245 mOsm/L.** * **Clinical Pearl:** Trisodium citrate is preferred over bicarbonate because it increases the shelf life of the ORS packets and is more effective in correcting acidosis.

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