Bacterial Skin Infections Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Bacterial Skin Infections. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Bacterial Skin Infections Indian Medical PG Question 1: A healthcare worker develops fever, night sweats, and cough. Sputum shows acid-fast bacilli. What is the next diagnostic test?
- A. Gram stain
- B. Serology for TB
- C. NAAT for TB (Correct Answer)
- D. Sputum culture
Bacterial Skin Infections Explanation: ***NAAT for TB***
- Nucleic Acid Amplification Tests (**NAAT**) rapidly confirm the presence of **Mycobacterium tuberculosis** DNA or RNA, crucial after an **acid-fast bacilli (AFB) smear** is positive [1].
- This test offers high sensitivity and specificity and can also detect **drug resistance**, guiding immediate treatment decisions [1].
*Gram stain*
- A **Gram stain** is not appropriate for **Mycobacterium tuberculosis** because these bacteria have a unique cell wall that makes them **acid-fast**, not readily stained by the Gram method.
- The initial finding of **acid-fast bacilli** already indicates a general type of organism, making a Gram stain redundant and uninformative for TB.
*Serology for TB*
- **Serological tests for TB** (detecting antibodies to M. tuberculosis) are generally **not recommended** for the diagnosis of active pulmonary TB due to their **poor sensitivity and specificity**.
- They have limited utility in diagnosing active disease and are not endorsed by major health organizations for this purpose.
*Sputum culture*
- **Sputum culture** is the **gold standard** for confirming TB diagnosis and for **drug susceptibility testing**, but it is a **slow process** (taking several weeks) [2].
- While essential for definitive diagnosis and resistance profiling, it is not the **"next" rapid diagnostic test** required given the positive AFB smear.
Bacterial Skin Infections Indian Medical PG Question 2: What is the diagnosis of a child with a small abrasion over the face who develops fever with chills, induration, and fiery red swelling over the face extending to the ear?
- A. Anthrax
- B. Carbuncle
- C. Cellulitis
- D. Erysipelas (Correct Answer)
Bacterial Skin Infections Explanation: ***Erysipelas***
- The presentation of **fiery red swelling** with well-demarcated, raised borders, rapidly extending from a small abrasion, especially on the face and involving the ear, is classic for erysipelas.
- It also includes systemic symptoms like **fever and chills** and **induration**, which are characteristic of this superficial skin infection usually caused by **Streptococcus pyogenes**.
*Anthrax*
- Cutaneous anthrax typically presents with a papule that develops into a **vesicle**, then a painless ulcer with a distinctive **black eschar**, which is not described here.
- While it can cause fever, the characteristic skin lesion is distinct from the red, spreading swelling seen in this case.
*Carbuncle*
- A carbuncle is a deep infection involving multiple hair follicles, presenting as a painful, interconnected lesion with **multiple draining sinuses**.
- It is typically more localized, deeper, and pus-filled than the superficial, rapidly spreading, fiery red swelling described.
*Cellulitis*
- Cellulitis is a deeper infection of the dermis and subcutaneous fat, presenting with redness, warmth, and tenderness, but its borders are typically **less well-demarcated** and not as raised as in erysipelas.
- While it can also occur on the face and cause systemic symptoms, the description of "fiery red" and "extending to the ear" with sharp borders makes erysipelas a more precise diagnosis.
Bacterial Skin Infections Indian Medical PG Question 3: Systemic Inflammatory Response Syndrome (SIRS) is characterized by all of the following EXCEPT:
- A. Hyperthermia (>38˚C)
- B. Platelet count (<1,00,000/mm3) (Correct Answer)
- C. Tachypnoea (>20/min)
- D. Hypothermia (<36˚C)
Bacterial Skin Infections Explanation: ***Platelet count (<1,00,000/mm3)***
- While **thrombocytopenia** can be a feature of severe infection or systemic illness, it is not one of the defining diagnostic criteria for **SIRS**. [1]
- The definition of SIRS primarily focuses on inflammatory markers like temperature, heart rate, respiratory rate, and white blood cell count.
*Hyperthermia (>38˚C)*
- **Fever** is a classic sign of inflammation and infection, and a temperature greater than 38°C is one of the key diagnostic criteria for SIRS. [2]
- This indicates the body's systemic inflammatory response to a perceived insult. [3]
*Tachypnoea (>20/min)*
- An increased **respiratory rate**, or **tachypnea**, is another important criterion for SIRS, reflecting increased metabolic demand or respiratory compensation.
- This criterion helps identify patients with a significant physiological response to inflammation.
*Hypothermia (<36˚C)*
- While less common than fever, **hypothermia** (temperature less than 36°C) can also be a sign of a severe systemic inflammatory response, particularly in immunocompromised or severely ill patients.
- It signifies a dysregulated thermoregulatory response in SIRS.
Bacterial Skin Infections Indian Medical PG Question 4: Which of the following are correct in respect of Systemic Inflammatory Response Syndrome (SIRS)?
1. It is caused by the release of lipopolysaccharide endotoxin from dying E. coli bacteria.
2. It is same as bacteraemia.
3. It results in Multiple Organ Dysfunction Syndrome (MODS).
4. White cell counts of more than 12 × 10^9/litre are present. Select the answer using the code given below.
- A. 2, 3 and 4
- B. 1, 2 and 3
- C. 1, 3 and 4 (Correct Answer)
- D. 1, 2 and 4
Bacterial Skin Infections Explanation: ***1, 3 and 4***
- **SIRS** can be caused by the release of **lipopolysaccharide endotoxin** from the cell wall of dying **Gram-negative bacteria** like *E. coli*, triggering a systemic inflammatory response [1].
- One of the major complications of **SIRS** is the progression to **Multiple Organ Dysfunction Syndrome (MODS)**, where organs begin to fail due to uncontrolled inflammation [1].
- A component of the **SIRS criteria** is a white blood cell count greater than 12 x 10^9/L or less than 4 x 10^9/L, or the presence of more than 10% immature band forms [1].
*2, 3 and 4*
- **Bacteremia** refers specifically to the presence of **viable bacteria** in the bloodstream, while **SIRS** is a broader inflammatory response that can be triggered by various causes (infectious or non-infectious).
- While bacteremia can lead to SIRS, SIRS can also occur without bacteremia (e.g., pancreatitis, trauma).
*1, 2 and 3*
- **Bacteremia** is not the same as SIRS; bacteremia is a potential cause of SIRS, but SIRS can arise from non-infectious conditions as well.
- The presence of bacteria in the blood (bacteremia) is a specific finding, whereas SIRS describes a *syndrome* of systemic inflammation.
*1, 2 and 4*
- This option incorrectly states that **SIRS is the same as bacteremia**, which it is not.
- Also, while bacteremia can lead to SIRS, **MODS** is a crucial and often fatal consequence of advanced SIRS, which is omitted in this option.
Bacterial Skin Infections Indian Medical PG Question 5: A 24-year-old woman with bacterial vaginosis is admitted to the hospital in preterm labor at 30 weeks. What is the most appropriate antibiotic regimen?
- A. Metronidazole 2g orally single dose
- B. Clindamycin 300mg orally twice daily for 7 days
- C. Clindamycin 5g vaginal cream for 7 days
- D. Metronidazole 500mg orally twice daily for 7 days (Correct Answer)
Bacterial Skin Infections Explanation: ***Metronidazole 500mg orally twice daily for 7 days***
- This regimen is an appropriate and effective treatment for **bacterial vaginosis**, with **oral metronidazole** being a first-line therapy.
- Treating **bacterial vaginosis** in a pregnant woman with **preterm labor** is crucial as untreated BV is a known risk factor for preterm birth and other obstetric complications.
*Metronidazole 2g orally single dose*
- While a **single-dose 2g metronidazole** regimen is an alternative for non-pregnant patients, it is generally **less effective** and not typically recommended for pregnant women, especially those in preterm labor, where complete eradication is critical.
- **Higher recurrence rates** have been reported with single-dose regimens compared to multi-day treatments.
*Clindamycin 300mg orally twice daily for 7 days*
- **Oral clindamycin** is an alternative treatment for bacterial vaginosis, but **metronidazole** is often preferred as a first-line option due to its efficacy and safety profile in pregnancy.
- The patient's condition of **preterm labor** would generally favor the most established and safest first-line treatment.
*Clindamycin 5g vaginal cream for 7 days*
- **Vaginal clindamycin cream** is an effective treatment for bacterial vaginosis, but in a patient with **preterm labor**, an **oral systemic antibiotic** is often preferred to ensure adequate tissue penetration and reduce the risk of ascending infection affecting the uterus.
- Vaginal creams might be less effective in preventing obstetric complications associated with BV compared to oral therapy in high-risk pregnancies.
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