Tuberculosis and Mycobacterial Diseases Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Tuberculosis and Mycobacterial Diseases. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Tuberculosis and Mycobacterial Diseases Indian Medical PG Question 1: Phagocytosis of mycobacterium tuberculosis by macrophages is mainly mediated by:
- A. Interleukin 6
- B. Interleukin 3
- C. Interleukin 12
- D. Interferon Gamma (Correct Answer)
Tuberculosis and Mycobacterial Diseases Explanation: ***Interferon Gamma***
- **Interferon gamma (IFN-γ)** is the most critical cytokine for **macrophage activation** in tuberculosis, enabling effective phagocytosis and intracellular killing of **Mycobacterium tuberculosis**.
- IFN-γ (produced by **Th1 cells** and **NK cells**) primes macrophages by:
- Enhancing **phagosome-lysosome fusion**
- Increasing expression of **Fc receptors** and **complement receptors** for better opsonization
- Stimulating production of **reactive oxygen species (ROS)** and **nitric oxide (NO)**
- Upregulating **MHC class II** for improved antigen presentation
- Without IFN-γ, macrophages cannot effectively control intracellular mycobacterial growth (as seen in **IFN-γ or IL-12 receptor deficiencies** leading to disseminated mycobacterial infections).
*Interleukin 6*
- **IL-6** is a pro-inflammatory cytokine involved in **acute-phase responses**, fever induction, and B-cell differentiation.
- While it contributes to systemic inflammatory responses in TB, it does not directly activate macrophages for mycobacterial phagocytosis and killing.
*Interleukin 3*
- **IL-3** is a **hematopoietic growth factor** that promotes proliferation and differentiation of myeloid and lymphoid progenitor cells in bone marrow.
- It plays no direct role in the effector functions of mature macrophages against *M. tuberculosis*.
*Interleukin 12*
- **IL-12** (produced by macrophages and dendritic cells) is essential for initiating **Th1 immunity** by promoting differentiation of naive CD4+ T cells into **Th1 cells** that produce IFN-γ.
- IL-12 acts **upstream** of IFN-γ in the immune cascade but does not directly mediate macrophage phagocytic function.
- The **IL-12/IFN-γ axis** is critical for TB immunity, but IFN-γ is the direct macrophage activator.
Tuberculosis and Mycobacterial Diseases Indian Medical PG Question 2: XDR means extensive drug resistance to
- A. Minimum of 1 injectable drug
- B. H+R
- C. 1 Fluoroquinolone
- D. Fluoroquinolone + at least one Group A drug (bedaquiline/linezolid) (Correct Answer)
Tuberculosis and Mycobacterial Diseases Explanation: ***Fluoroquinolone + at least one Group A drug (bedaquiline/linezolid)***
- **Extensively drug-resistant (XDR) tuberculosis** is defined by the WHO (2021) as TB with resistance to **rifampicin** (RR-TB baseline), plus resistance to any **fluoroquinolone** (levofloxacin or moxifloxacin), plus resistance to at least one additional **Group A drug** (bedaquiline or linezolid).
- This represents the current standard definition emphasizing resistance to the most critical second-line oral agents.
- XDR-TB is built upon **MDR-TB** (H+R resistance) with additional resistance patterns that make treatment extremely challenging.
*Minimum of 1 injectable drug*
- Injectable drug resistance (aminoglycosides, capreomycin) was part of the **old XDR-TB definition** (pre-2021) but is no longer required.
- The WHO updated the definition to focus on more effective oral drugs rather than injectables.
*H+R*
- Resistance to **isoniazid (H)** and **rifampicin (R)** defines **multidrug-resistant (MDR) tuberculosis**, not XDR-TB.
- MDR-TB is the foundation upon which XDR-TB is built, but it represents a less severe form of drug resistance.
*1 Fluoroquinolone*
- While fluoroquinolone resistance is a **necessary component** of XDR-TB, it is **not sufficient alone**.
- XDR-TB requires fluoroquinolone resistance **plus** additional resistance to Group A drugs (bedaquiline or linezolid).
Tuberculosis and Mycobacterial Diseases Indian Medical PG Question 3: A poverty-stricken mother suffering from active tuberculosis delivers a baby. Which one of the following would be the most appropriate advice in her case?
- A. Breast feeding and BCG immunization
- B. Breast feeding and isoniazid administration (Correct Answer)
- C. Expressed breast milk and BCG immunization
- D. Stop feeds and isoniazid administration
Tuberculosis and Mycobacterial Diseases Explanation: ***Breast feeding and isoniazid administration***
- **Breastfeeding** is safe and encouraged for infants of mothers with active tuberculosis, as the benefits of breast milk (nutrition, antibodies) outweigh the minimal risk of TB transmission through milk.
- **Isoniazid (INH) chemoprophylaxis** for the infant provides additional protection in high-risk exposure settings, particularly when the mother has active pulmonary TB and close contact is inevitable.
- This approach represents a conservative strategy prioritizing immediate chemoprophylaxis in a poverty-stricken setting where follow-up may be challenging.
*Breast feeding and BCG immunization*
- **Breastfeeding** is beneficial and appropriate.
- **BCG immunization** at birth is the current standard recommendation per WHO and IAP guidelines for infants born to TB-positive mothers.
- However, in settings with very high exposure risk and uncertain follow-up, some protocols additionally recommend INH prophylaxis, making the first option more comprehensive for this specific scenario.
*Expressed breast milk and BCG immunization*
- Expressing breast milk offers no significant additional protection against TB transmission compared to direct breastfeeding.
- Direct breastfeeding has additional benefits for mother-infant bonding and is not contraindicated in maternal TB.
- While **BCG immunization** is appropriate, this option unnecessarily complicates feeding.
*Stop feeds and isoniazid administration*
- **Stopping breastfeeding** is not indicated and would deprive the infant of essential nutrition and passive immunity.
- Breastfeeding is not contraindicated in maternal tuberculosis.
- While **isoniazid administration** may be appropriate, cessation of feeding is an incorrect recommendation.
Tuberculosis and Mycobacterial Diseases Indian Medical PG Question 4: Mycobacterium tuberculosis having resistance to rifampicin, isoniazid, and pyrazinamide is described as -
- A. Drug resistant tuberculosis
- B. Extremely drug resistant tuberculosis
- C. Multi drug resistant tuberculosis (Correct Answer)
- D. None of the options
Tuberculosis and Mycobacterial Diseases Explanation: ***Multi drug resistant tuberculosis***
- This classification specifically refers to *Mycobacterium tuberculosis* resistant to at least **rifampicin** and **isoniazid**, which are the two most potent first-line anti-TB drugs.
- While resistance to **pyrazinamide** is also present in this case, the definition of multidrug-resistant tuberculosis (MDR-TB) primarily hinges on resistance to these two core drugs [1].
*Drug resistant tuberculosis*
- This is a broad term that can apply to any resistance to one or more anti-TB drugs, but it is not specific enough for resistance to these crucial first-line agents [1].
- It does not convey the clinical and public health implications of resistance to both rifampicin and isoniazid.
*Extremely drug resistant tuberculosis*
- **Extensively drug-resistant tuberculosis (XDR-TB)** is defined as MDR-TB (resistance to rifampicin and isoniazid) plus resistance to any **fluoroquinolone** and at least one of the three injectable second-line drugs (amikacin, kanamycin, or capreomycin).
- The given resistance pattern does not include fluoroquinolones or injectable second-line drugs.
*None of the options*
- This option is incorrect because the resistance pattern described perfectly fits the definition of multidrug-resistant tuberculosis.
Tuberculosis and Mycobacterial Diseases Indian Medical PG Question 5: Which one of the following statements is true regarding the pathogenicity of Mycobacteria species?
- A. M. Africanum is typically contracted from humans or monkeys.
- B. M. marinum is primarily associated with skin infections. (Correct Answer)
- C. M. Kansasii is primarily an environmental organism that rarely causes human disease.
- D. M. tuberculosis and M. bovis have distinct pathogenic profiles in humans.
Tuberculosis and Mycobacterial Diseases Explanation: ****M. marinum is primarily associated with skin infections.****
- *Mycobacterium marinum* is famously associated with "fish tank granuloma" or "swimming pool granuloma," causing **cutaneous lesions** following exposure to contaminated water.
- Infection typically occurs through breaks in the skin from contact with infected fish, aquariums, or other aquatic environments.
*M. Kansasii is primarily an environmental organism that rarely causes human disease.*
- While *M. kansasii* is an environmental organism, it is a significant cause of **nontuberculous mycobacterial lung disease** in humans, resembling tuberculosis.
- It does not rarely cause human disease; it's one of the more common causes of atypical mycobacterial infections.
*M. Africanum is typically contracted from humans or monkeys.*
- *M. africanum* is a species of *Mycobacterium tuberculosis* complex (MTBC) and is primarily a pathogen of **humans**, particularly in parts of West and East Africa.
- It is **not typically contracted from monkeys**; the primary reservoir for *M. africanum* is humans.
*M. tuberculosis and M. bovis have distinct pathogenic profiles in humans.*
- Both *M. tuberculosis* and *M. bovis* are members of the MTBC and cause **tuberculosis in humans**, with *M. bovis* traditionally transmitted through contaminated dairy products.
- While *M. tuberculosis* is the primary cause of human TB and *M. bovis* can cause extrapulmonary and pulmonary disease, their pathogenic profiles in humans are often **similar** in presentation with respect to the disease they cause, though modes of transmission differ.
Tuberculosis and Mycobacterial Diseases Indian Medical PG Question 6: Most common extra pulmonary involvement of TB ?
- A. Bone
- B. Ileocecal
- C. Lymph nodes (Correct Answer)
- D. Pleura
Tuberculosis and Mycobacterial Diseases Explanation: ***Bone***
- While **skeletal tuberculosis** can occur, particularly in the spine (**Pott's disease**), it is not the most common extrapulmonary manifestation [2].
- Bone involvement typically presents with localized pain, swelling, and sometimes neurological deficits [2].
*Ileocecal*
- **Gastrointestinal TB**, especially involving the **ileocecal region**, is a significant form of extrapulmonary TB.
- It often leads to abdominal pain, weight loss, and malabsorption, but it is less common than lymph node involvement.
*Lymph nodes*
- **Tuberculous lymphadenitis** (scrofula) is the **most common extrapulmonary manifestation of TB**, especially in immunocompetent individuals and children [1].
- Typically presents as painless, slowly enlarging lymph nodes, most often in the cervical region [1].
*Pleura*
- **Pleural effusion** (tuberculous pleurisy) is a common manifestation of TB and involves the lining of the lungs.
- Although frequent, it is generally considered a **pulmonary complication** or a contiguous spread from the lung rather than a distinctly extrapulmonary site like the lymph nodes.
Tuberculosis and Mycobacterial Diseases Indian Medical PG Question 7: A 45-year-old HIV-positive man presents with fever and cough. Sputum culture shows acid-fast bacilli. Which of the following drugs is essential in the treatment regimen?
- A. Doxycycline
- B. Amoxicillin
- C. Isoniazid (Correct Answer)
- D. Ciprofloxacin
Tuberculosis and Mycobacterial Diseases Explanation: ***Isoniazid***
- The presence of **acid-fast bacilli** (AFB) in sputum, especially in an **HIV-positive** individual with fever and cough, strongly indicates **tuberculosis (TB)** [1].
- **Isoniazid** is a cornerstone drug in **first-line anti-tuberculosis therapy** and is essential for effective treatment [1].
*Doxycycline*
- **Doxycycline** is a tetracycline antibiotic primarily used for bacterial infections like **atypical pneumonia**, Lyme disease, and certain sexually transmitted infections.
- It has **no significant activity against Mycobacterium tuberculosis** and is not part of TB treatment.
*Amoxicillin*
- **Amoxicillin** is a penicillin-class antibiotic effective against a range of common bacterial infections, but it is **ineffective against mycobacteria**.
- It would not be used to treat **tuberculosis**.
*Ciprofloxacin*
- **Ciprofloxacin** is a fluoroquinolone antibiotic used for various bacterial infections, including some respiratory and urinary tract infections.
- While some fluoroquinolones are used as **second-line agents** in specific multi-drug resistant TB regimens, **ciprofloxacin** is not a first-line drug and is generally reserved for particular circumstances, unlike isoniazid which is essential for initial therapy.
Tuberculosis and Mycobacterial Diseases Indian Medical PG Question 8: What should you do next for a 35-year-old man who is positive for HBsAg and HBeAg, discovered incidentally during blood donation screening, with normal SGOT and SGPT laboratory values?
- A. HBV-DNA estimation (Correct Answer)
- B. Observation
- C. Liver biopsy
- D. Interferon therapy
Tuberculosis and Mycobacterial Diseases Explanation: ***HBV-DNA estimation***
- The presence of **HBsAg** and **HBeAg** indicates **active viral replication**, necessitating quantification of HBV-DNA to assess viral load [1].
- Normal SGOT and SGPT suggest compensated liver function, but **viral load** is crucial for staging the disease and guiding future management [1].
*Observation*
- While liver enzymes are normal, the presence of **HBsAg** and **HBeAg** indicates active hepatitis B infection, which warrants further investigation, not just observation [1].
- Undiagnosed and untreated chronic hepatitis B can lead to serious complications such as **cirrhosis** and **hepatocellular carcinoma** [1].
*Liver biopsy*
- **Liver biopsy** is an invasive procedure typically reserved for cases where histological assessment is required to confirm **fibrosis** or **inflammation severity**, or when there's discordance between viral markers and clinical presentation.
- It's not the initial step for a patient with normal transaminases and clear serological markers of active infection; **HBV-DNA estimation** is generally performed first [1].
*Interferon therapy*
- **Interferon therapy** is a treatment for chronic hepatitis B, but initiating treatment requires a comprehensive assessment including **HBV-DNA levels**, in addition to liver enzyme levels and evaluation of liver damage [2].
- It would be premature to consider treatment without a **viral load** measurement and a full workup to determine the phase of infection and the need for therapy [2].
Tuberculosis and Mycobacterial Diseases Indian Medical PG Question 9: Devi, a 28 year female, has diarrhea, confusion, high grade fever with bilateral pneumonitis. The diagnosis is -
- A. H. influenzae
- B. Legionella (Correct Answer)
- C. Streptococcus pneumoniae
- D. Neisseria meningitidis
Tuberculosis and Mycobacterial Diseases Explanation: ***Legionella***
- The constellation of **diarrhea, confusion (neurological symptoms), high-grade fever, and bilateral pneumonitis** is highly characteristic of **Legionnaires' disease**, caused by *Legionella pneumophila* [1].
- This organism commonly causes **extrapulmonary symptoms** such as gastrointestinal and neurological manifestations, in addition to severe pneumonia.
*H. influenzae*
- While *H. influenzae* can cause pneumonia, it typically presents with **lobar pneumonia** [1] and rarely involves gastrointestinal or significant neurological symptoms beyond general debility.
- It is more commonly associated with **epiglottitis** and **meningitis** in unimmunized children.
*Streptococcus pneumoniae*
- *Streptococcus pneumoniae* is the most common cause of **community-acquired pneumonia**, often presenting with acute onset of fever, chills, and productive cough [1].
- While it can cause bacteremia and sepsis, **gastrointestinal symptoms like prominent diarrhea and significant neurological confusion** are not typical primary features of pneumococcal pneumonia.
*Neisseria meningitidis*
- *Neisseria meningitidis* is primarily known for causing **meningitis** and **meningococcemia**, involving symptoms like stiff neck, headache, rash, and fever [1].
- While it can sometimes cause pneumonia, the combination with **prominent diarrhea and severe, bilateral pneumonitis** as the primary presentation is not characteristic; the neurological symptoms point more towards Legionella given the other features.
Tuberculosis and Mycobacterial Diseases Indian Medical PG Question 10: All the following are causes of a painful limp, except which of the following?
- A. Slipped femoral epiphysis (SCFE)
- B. Tuberculosis (TB) of the hip
- C. Perthes disease (Legg-Calvé-Perthes disease)
- D. Infantile Coxa Vara (Coxa Vara) (Correct Answer)
Tuberculosis and Mycobacterial Diseases Explanation: ***Infantile Coxa Vara (Coxa Vara)***
- **Infantile coxa vara** is a developmental condition characterized by a **reduced femoral neck-shaft angle**, often leading to a painless waddling gait or limp.
- While it causes a limp, the limp itself is typically **painless**, distinguishing it from the other conditions listed.
*Slipped femoral epiphysis (SCFE)*
- **SCFE** involves displacement of the **femoral head** from the neck through the growth plate and is a classic cause of a **painful limp** in adolescents, often associated with obesity.
- Patients typically experience **hip, groin, thigh, or knee pain** and may present with a shortened leg with external rotation.
*Tuberculosis (TB) of the hip*
- **TB of the hip** is a chronic infectious arthritis that causes significant **pain**, swelling, and reduced range of motion, leading to a **painful limp**.
- It often presents insidiously with **constitutional symptoms** like fever and weight loss, in addition to localized pain.
*Perthes disease (Legg-Calvé-Perthes disease)*
- **Perthes disease** is characterized by avascular necrosis of the **femoral head** in children, causing a **painful limp** and restricted hip movement.
- The pain typically worsens with activity and improves with rest, and may be referred to the knee or thigh.
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