Non-Communicable Diseases — MCQs

Non-Communicable Diseases Indian Medical PG Practice Questions and MCQs

Question 121: Which of the following statements regarding dengue fever is false?

A. It is both endemic and epidemic.
B. It is a mosquito-borne arboviral disease.
C. Affected by ambient temperature in the last 30 years in India. (Correct Answer)
D. It is self-limiting.

Explanation: ### Explanation **1. Why Option C is the Correct (False) Statement:** While it is a common misconception that dengue is strictly seasonal or temperature-dependent, the epidemiological trend in India over the last 30 years shows that dengue has become **perennial** in many states. While ambient temperature affects the extrinsic incubation period of the virus and mosquito breeding cycles, the rapid spread of dengue in India is primarily driven by **unplanned urbanization, inadequate water management, and increased population mobility**, rather than just temperature fluctuations. Therefore, stating it is simply "affected by ambient temperature" as a defining characteristic of its 30-year trend is considered the least accurate (false) statement in the context of its evolving epidemiology. **2. Analysis of Other Options:** * **Option A (Endemic and Epidemic):** This is **true**. Dengue is endemic in over 100 countries (including India) with periodic explosive outbreaks (epidemics) occurring every 3–5 years. * **Option B (Mosquito-borne arboviral disease):** This is **true**. It is caused by the Dengue virus (DENV 1-4), a Flavivirus transmitted primarily by the *Aedes aegypti* mosquito. * **Option D (Self-limiting):** This is **true**. In the majority of cases, Dengue Fever is a self-limiting febrile illness. Only a small percentage of patients progress to severe forms like Dengue Hemorrhagic Fever (DHF) or Dengue Shock Syndrome (DSS). **3. High-Yield Clinical Pearls for NEET-PG:** * **Vector:** *Aedes aegypti* (Day biter, "Tiger mosquito," breeds in artificial collections of clean water). * **Incubation Period:** 3–14 days (commonly 4–7 days). * **Saddle-back Fever:** Characterized by a biphasic fever pattern. * **Tourniquet Test:** Used as a screening tool for capillary fragility (Positive if >10–20 petechiae per square inch). * **Critical Period:** The 24–48 hours during "defervescence" (when fever drops) is when plasma leakage and shock are most likely to occur. * **NS1 Antigen:** Best for early diagnosis (Days 1–5).

Question 122: Cholera is transmitted by which of the following?

A. Contaminated food or water (Correct Answer)
B. Vaccination provides 90% efficiency
C. Healthy carriers
D. Chlorination is not effective

Explanation: **Explanation:** **Cholera** is an acute diarrheal infection caused by the ingestion of the bacterium *Vibrio cholerae*. **1. Why Option A is Correct:** The primary mode of transmission for Cholera is the **fecal-oral route**. This occurs most commonly through the consumption of **contaminated water** or **contaminated food** (especially raw or undercooked shellfish and vegetables grown with sewage water). In endemic areas, water is the most frequent vehicle, while food-borne outbreaks are common in non-endemic regions. **2. Why Other Options are Incorrect:** * **Option B:** Current oral cholera vaccines (OCVs) like Shanchol or Euvichol provide approximately **60–80% protection**, not 90%. Protection also diminishes significantly after 2–3 years. * **Option C:** In Cholera, **"Healthy carriers" are rare**. The transmission is primarily driven by "Incubatory" or "Convalescent" carriers, and more importantly, by subclinical cases (cases that are mild but still shed the bacteria). * **Option D:** **Chlorination is highly effective** against *Vibrio cholerae*. It is one of the standard public health interventions to ensure safe drinking water during outbreaks. **High-Yield Clinical Pearls for NEET-PG:** * **Rice Water Stools:** The hallmark clinical sign (non-sticky, colorless with flakes of mucus). * **Haldane’s Rule:** "Cholera is a disease of the poor; it begins where the law of hygiene ends." * **Incubation Period:** Very short, ranging from a few hours to 5 days (usually 1–2 days). * **Treatment of Choice:** Prompt **Rehydration** (ORS/IV fluids). Doxycycline is the drug of choice for reducing the duration of shedding in adults. * **Epidemiology:** Serogroups **O1** (Classical and El Tor biotypes) and **O139** are the main causes of epidemics. Currently, the 7th pandemic (El Tor) is ongoing.

Question 123: What is the duration that defines a permanent carrier for Hepatitis B Virus (HBV)?

A. More than 6 months (Correct Answer)
B. More than 1 month
C. More than 1 year
D. More than 2 years

Explanation: **Explanation:** The definition of a **chronic or permanent carrier** of Hepatitis B is based on the persistence of the **Hepatitis B surface Antigen (HBsAg)** in the blood for a specific duration. **1. Why Option A is Correct:** According to the World Health Organization (WHO) and standard epidemiological guidelines, a person is classified as a chronic carrier if HBsAg persists in the serum for **more than 6 months**. This duration is clinically significant because most acute HBV infections in adults resolve within 6 months. Persistence beyond this window indicates that the immune system has failed to clear the virus, leading to a chronic infection state. **2. Why Other Options are Incorrect:** * **Option B (1 month):** This represents the acute phase of infection. Many patients are HBsAg positive during the incubation and early symptomatic period but go on to clear the virus spontaneously. * **Options C & D (1 year / 2 years):** While a carrier will remain positive for these durations, the formal medical definition for "chronic" status is established much earlier (at the 6-month mark) to initiate monitoring for complications like cirrhosis or hepatocellular carcinoma. **3. High-Yield Clinical Pearls for NEET-PG:** * **Age Factor:** The risk of becoming a carrier is inversely proportional to age. Approximately **90% of infected newborns** become chronic carriers, compared to only **5–10% of infected adults**. * **Infectivity Marker:** While HBsAg defines the carrier state, **HBeAg** (Envelope Antigen) is the marker of high infectivity and active viral replication. * **Super-carrier:** A "super-carrier" is a person who is both HBsAg positive and HBeAg positive, possessing a very high viral load. * **Healthy Carrier:** Defined as HBsAg positive for >6 months but with normal ALT levels and low/undetectable HBV DNA.

Question 124: Which of the following is a method of natural family planning?

A. Abstinence
B. Coitus interruptus
C. Basal Body Temperature (BBT) charting (Correct Answer)
D. Rhythm method (safe period)

Explanation: **Explanation:** **Correct Option: C. Basal Body Temperature (BBT) charting** Natural Family Planning (NFP) methods, also known as **Fertility Awareness-Based Methods (FABM)**, rely on identifying the fertile window of the menstrual cycle through physiological markers. BBT charting is a primary NFP method where a woman measures her body temperature every morning before rising. A slight rise in temperature (0.4°F to 1.0°F) occurs immediately **after ovulation** due to the thermogenic effect of **Progesterone**. By tracking this shift, a woman can confirm that ovulation has occurred and identify the post-ovulatory infertile phase. **Analysis of Incorrect Options:** * **A. Abstinence:** While a form of birth control, it is categorized as a **behavioral method** or a "permanent" choice of non-activity rather than a method of "planning" based on cycle monitoring. * **B. Coitus interruptus:** This is a **traditional/behavioral method** (withdrawal). It does not involve tracking physiological signs of fertility and has a high failure rate due to the presence of sperm in pre-ejaculatory fluid. * **D. Rhythm method (Safe Period):** While often confused with NFP, the Rhythm method is a **calendar-based calculation** based on previous cycle lengths. Modern NFP (like BBT or the Symptothermal method) is considered more accurate because it uses real-time biological signs rather than historical averages. **NEET-PG High-Yield Pearls:** * **Symptothermal Method:** The most effective NFP method; it combines BBT, cervical mucus changes (Billings method), and calendar calculations. * **Spinnbarkeit Test:** Refers to the elasticity of cervical mucus; during ovulation (under estrogen influence), mucus becomes thin, watery, and can be stretched 10–15 cm. * **Pearl Index:** Used to measure contraceptive failure rates. NFP methods generally have a higher typical-use failure rate compared to LARC (Long-Acting Reversible Contraceptives). * **Lactational Amenorrhea Method (LAM):** Effective only if the mother is fully breastfeeding, is less than 6 months postpartum, and remains amenorrheic.

Question 125: Which of the following is a second-generation Intrauterine Device (IUD)?

A. Progestasert
B. Mirena
C. CuT-200 (Correct Answer)
D. Lippes Loop

Explanation: **Explanation:** Intrauterine Devices (IUDs) are classified into three generations based on their composition and mechanism of action. Understanding this classification is high-yield for NEET-PG. **Why CuT-200 is correct:** **CuT-200** belongs to the **Second Generation IUDs**, which are characterized by the addition of **copper** to a plastic (polyethylene) frame. Copper acts as a spermicide by causing a local inflammatory response in the endometrium and altering cervical mucus. The "200" represents the surface area of copper in square millimeters. Other examples include CuT-380A, Multiload (MLCu-250/375), and Nova T. **Analysis of Incorrect Options:** * **Lippes Loop (Option D):** This is a **First Generation IUD**. These are non-medicated, inert devices usually made of polyethylene or stainless steel. They are rarely used today due to higher expulsion and failure rates. * **Progestasert and Mirena (Options A & B):** These are **Third Generation IUDs** (Hormone-releasing IUDs). * **Progestasert** releases Progesterone (first-generation hormonal IUD). * **Mirena** (LNG-20) releases Levonorgestrel and is the most commonly used hormonal IUD today. **Clinical Pearls for NEET-PG:** * **Ideal Candidate:** Multiparous women in a stable monogamous relationship. * **Mechanism of Action:** Primarily prevents fertilization by being gametotoxic (especially copper IUDs). * **Most Common Side Effect:** Excessive menstrual bleeding (menorrhagia) is the #1 reason for removal. * **Most Common Complication:** Pain. * **CuT-380A:** Currently the most effective copper IUD with a lifespan of **10 years**.

Question 126: Which of the following is NOT an epidemiological feature of Japanese encephalitis?

A. The virus infects extra-human hosts.
B. Man is an incidental host.
C. Pigs can show clinical manifestations. (Correct Answer)
D. Epidemics have been reported in Karnataka.

Explanation: **Explanation:** Japanese Encephalitis (JE) is a zoonotic viral infection caused by a Group B Arbovirus (Flavivirus) and transmitted primarily by *Culex tritaeniorhynchus* mosquitoes. **Why Option C is the correct answer:** In the transmission cycle of JE, **pigs act as the "Amplifier Host."** While the virus multiplies rapidly in pigs, leading to high-titre viremia (which infects mosquitoes), the infection in pigs is **asymptomatic**. They do not show clinical manifestations of encephalitis. This makes them the perfect reservoir for maintaining the virus in the environment without dying off. **Analysis of other options:** * **Option A (Extra-human hosts):** JE is a zoonotic disease. The natural cycle involves extra-human hosts, primarily **Ardeid birds** (herons, egrets) as the natural reservoir and **pigs** as the amplifier host. * **Option B (Man is an incidental host):** Humans are "dead-end" hosts. Because the level of viremia in humans is low and transient, a mosquito biting an infected human cannot pick up enough virus to infect another person. * **Option D (Epidemics in Karnataka):** JE is endemic in several parts of India. Major outbreaks have been historically reported in states like Uttar Pradesh, Bihar, West Bengal, Assam, and South Indian states including **Karnataka** (especially the Bellary and Kolar districts) and Andhra Pradesh. **High-Yield NEET-PG Pearls:** * **Vector:** *Culex tritaeniorhynchus* (breeds in stagnant water/paddy fields). * **Reservoir/Maintenance Host:** Ardeid birds. * **Amplifier Host:** Pigs (Ratio of 1:1000—one infected pig can infect a thousand mosquitoes). * **Dead-end Hosts:** Humans and Horses. * **Vaccine:** Live attenuated **SA-14-14-2** (most common in India) or killed mouse brain-derived (Nakayama strain).

Question 127: Which virus is documented to cause fetal damage?

A. Hepatitis A
B. Varicella (Correct Answer)
C. Measles
D. Arbovirus

Explanation: **Explanation:** The correct answer is **Varicella (B)**. **Why Varicella is correct:** Varicella-Zoster Virus (VZV) is a well-documented teratogen. When a pregnant woman contracts primary varicella (chickenpox) during the first 20 weeks of gestation, the virus can cross the placenta and cause **Congenital Varicella Syndrome**. This syndrome is characterized by skin scarring (cicatricial lesions in a dermatomal distribution), limb hypoplasia, microcephaly, chorioretinitis, and cataracts. **Why the other options are incorrect:** * **Hepatitis A (A):** This is an enterically transmitted virus (fecal-oral). While it can cause acute hepatitis in the mother, it is not associated with congenital malformations or direct fetal damage. * **Measles (C):** While measles infection during pregnancy is associated with adverse outcomes like spontaneous abortion, premature labor, and low birth weight, it is **not** documented to be teratogenic (it does not cause structural fetal malformations). * **Arbovirus (D):** Most arboviruses (like Dengue or West Nile) do not typically cause fetal damage. *Note:* While Zika virus (an arbovirus) is a known teratogen, it is not the standard answer in this classic MCQ context compared to the established risk of Varicella. **NEET-PG High-Yield Pearls:** * **Congenital Rubella Syndrome (CRS):** The most common viral cause of fetal damage (Classic triad: Cataract, Deafness, Cardiac defects like PDA). * **Cytomegalovirus (CMV):** The most common *infectious* cause of sensorineural hearing loss and mental retardation in neonates. * **Varicella Prophylaxis:** If a susceptible pregnant woman is exposed to VZV, **Varicella-Zoster Immunoglobulin (VZIG)** should be administered within 96 hours to prevent maternal and fetal complications.

Question 128: The calendar method for contraception was described by whom?

A. Bitings
B. Ogino (Correct Answer)
C. Wallace
D. Ogive

Explanation: **Explanation:** The **Calendar Method** (also known as the Rhythm Method) is a natural family planning technique based on the physiological timing of ovulation. It was independently described by **Kyusaku Ogino** (Japan) and **Hermann Knaus** (Austria) in the 1920s. Therefore, it is often referred to as the **Ogino-Knaus Method**. **Why the correct answer is right:** * **Ogino (B):** Dr. Kyusaku Ogino discovered that ovulation occurs approximately 14 days before the next menstrual period. By calculating the shortest and longest cycles over 6–12 months, a woman can estimate her "fertile window" (abstaining from intercourse during this time to prevent pregnancy). **Why the incorrect options are wrong:** * **Bitings (A):** This is a distractor; there is no significant contributor to contraception by this name. (Note: "Billings" refers to the Cervical Mucus Method, which is a different natural method). * **Wallace (C):** Most commonly associated with the "Rule of Nines" used in assessing the percentage of Body Surface Area (BSA) in burn patients. * **Ogive (D):** This is a statistical term referring to a cumulative frequency polygon, used in epidemiology and biostatistics, not contraception. **High-Yield Clinical Pearls for NEET-PG:** * **Calculation Formula:** To find the fertile period, subtract 18 days from the shortest cycle (start of fertile period) and 11 days from the longest cycle (end of fertile period). * **Pearl Index:** The failure rate of the calendar method is relatively high (approx. 9–25 per 100 woman-years), making it less reliable than hormonal or barrier methods. * **Prerequisite:** It is only suitable for women with regular menstrual cycles. * **Standard Days Method (SDM):** A simplified version of the calendar method for women with cycles between 26–32 days, where days 8–19 are considered fertile.

Question 129: Which of the following is NOT a demographic process?

A. Fertility
B. Morbidity (Correct Answer)
C. Mortality
D. Social mobility

Explanation: **Explanation:** Demography is the scientific study of human populations, primarily focusing on their size, structure, and development. The dynamics of a population are governed by five key **demographic processes** that lead to changes in population size and distribution. **Why Morbidity is the correct answer:** **Morbidity** refers to the state of being ill or the occurrence of disease within a population. While morbidity is a crucial indicator in public health and epidemiology, it is **not** considered a demographic process because the mere occurrence of illness does not, by itself, change the size or structure of a population. Only when a disease leads to death (Mortality) does it affect demographic dynamics. **Analysis of Incorrect Options:** * **Fertility (A):** This is the actual reproductive performance of a population. It is a primary demographic process as it adds new members to the population. * **Mortality (C):** This refers to the occurrence of deaths. It is a vital demographic process as it removes members from the population. * **Social Mobility (D):** This refers to the movement of individuals or groups between different social strata (e.g., change in socio-economic status). Along with **Migration** (spatial movement) and **Marriage**, it is classified as a demographic process because it alters the composition and structure of the population. **High-Yield Pearls for NEET-PG:** * **The 5 Demographic Processes:** Fertility, Mortality, Marriage, Migration, and Social Mobility. * **Demographic Cycle:** Remember the stages (High stationary to Declining). India is currently in **Late Expanding (Stage 3)**. * **Vital Statistics:** These are derived from the registration of "Vital Events" (Births, Deaths, Marriages, Divorces). * **Morbidity Indicators:** Measured by Incidence and Prevalence; these are tools of Epidemiology, not the primary drivers of Demography.

Question 130: Which of the following is NOT a risk factor for the development of Diabetes Mellitus?

A. Obesity
B. Sedentary lifestyle
C. High intake of vitamin A (Correct Answer)
D. Excess fat intake

Explanation: **Explanation:** Diabetes Mellitus (DM) is a chronic metabolic disorder characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. The development of Type 2 Diabetes is multifactorial, involving both non-modifiable (age, genetics) and modifiable risk factors. **Why "High intake of Vitamin A" is the correct answer:** There is no established clinical evidence linking high Vitamin A intake to the development of Diabetes Mellitus. In fact, some studies suggest that Vitamin A and its derivatives (retinoids) are essential for the normal function of pancreatic beta cells. While excessive Vitamin A can lead to hypervitaminosis A (causing bone pain, liver damage, and skin changes), it is not a risk factor for hyperglycemia or insulin resistance. **Analysis of incorrect options:** * **Obesity (Option A):** This is the most significant modifiable risk factor. Adipose tissue, especially visceral fat, releases non-esterified fatty acids and inflammatory cytokines (adipokines) that lead to insulin resistance. * **Sedentary Lifestyle (Option B):** Lack of physical activity reduces glucose uptake by skeletal muscles and decreases insulin sensitivity, directly contributing to the metabolic syndrome. * **Excess Fat Intake (Option D):** Diets high in saturated fats and trans fats contribute to obesity and dyslipidemia, which impair insulin signaling pathways and promote "lipotoxicity" in pancreatic cells. **High-Yield Clinical Pearls for NEET-PG:** * **The "Rule of Halves" in Diabetes:** Roughly half of the cases are undiagnosed; half of those diagnosed receive care; and half of those treated achieve glycemic targets. * **Screening:** According to the National Programme for Prevention and Control of NCDs (NPCDCS), screening for DM in India should begin at **age 30**. * **Diagnostic Cut-off:** HbA1c **≥ 6.5%** or Fasting Plasma Glucose **≥ 126 mg/dL** are diagnostic for Diabetes. * **Modifiable vs. Non-modifiable:** Remember that while we can change diet and activity, we cannot change "Thrifty Genotype" or ethnicity (South Asians are at higher risk at lower BMIs).

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