Infectious Diseases Practice Questions

Q: Corticosteroids are absolutely contraindicated in which of the following types of tuberculosis?

Intestinal. **Explanation:** In the management of Tuberculosis (TB), corticosteroids are used as an adjuvant to anti-tubercular therapy (ATT) to reduce life-threatening inflammation and prevent complications like fibrosis or adhesions [1]. However, they are **absolutely contraindicated in Intestinal TB.** **Why Intestinal TB?** The primary concern in Intestinal TB is the risk of **bowel perforation**. Corticosteroids inhibit the healing process and mask signs of peritonitis. Since intestinal TB often involves ulceration of the Peyer's patches and thinning of the bowel wall, steroids can lead to "silent" perforation, which is a surgical emergency with high mortality. **Analysis of Other Options:** * **Meningeal TB (Option B):** This is a **strong indication** for steroids (e.g., Dexamethasone). They reduce cerebral edema, prevent basal arachnoiditis, and decrease the incidence of hydrocephalus and neurological deficits [1]. * **Miliary TB (Option A):** Steroids are often used as an adjunct, especially if there is associated adrenal insufficiency or severe respiratory distress (ARDS) to improve oxygenation and reduce the systemic inflammatory response. * **Renal TB (Option D):** Steroids are indicated specifically to prevent **ureteric strictures** and subsequent hydronephrosis during the healing phase of the disease. **High-Yield Clinical Pearls for NEET-PG:** * **Indications for Steroids in TB:** TB Meningitis (most common indication), TB Pericarditis (to prevent constrictive pericarditis), Pleural effusion (for rapid resolution), and Renal TB (to prevent strictures) [1]. * **Contraindications:** Intestinal TB (due to perforation risk) and Multi-Drug Resistant TB (MDR-TB) unless life-threatening inflammation is present. * **Standard Regimen:** Prednisolone (1-2 mg/kg) tapered over 4–8 weeks is the typical adjuvant protocol.

Q: Corticosteroids are absolutely contraindicated in which of the following types of tuberculosis?

Intestinal. **Explanation:** In the management of Tuberculosis (TB), corticosteroids are used as an adjuvant therapy to reduce the inflammatory response and prevent complications like fibrosis or excessive exudation. However, they are **absolutely contraindicated in Intestinal TB.** **Why Intestinal TB?** The primary concern in Intestinal TB is the risk of **bowel perforation**. Corticosteroids inhibit the healing process and mask signs of peritonitis. In the gut, TB typically causes ulcerations; steroids can lead to thinning of the intestinal wall, preventing the formation of protective adhesions and significantly increasing the risk of a life-threatening perforation. **Analysis of Other Options:** * **Meningeal TB (Option B):** This is a primary indication for steroids [1]. They reduce intracranial pressure, decrease cerebral edema, and prevent basal arachnoiditis, which significantly lowers mortality and neurological deficits [1]. * **Miliary TB (Option A):** Steroids are often used as an adjunct, especially if there is associated respiratory distress (ARDS) or adrenal insufficiency, to dampen the overwhelming systemic inflammatory response. * **Renal TB (Option D):** While not mandatory for all cases, steroids are used to prevent ureteric strictures and subsequent hydronephrosis during the healing phase of the disease. **High-Yield Clinical Pearls for NEET-PG:** * **Indications for Steroids in TB:** Meningitis (Grade I, II, III) [1], Pericarditis (to prevent constrictive pericarditis) [1], Pleural effusion (to hasten fluid absorption), and Laryngeal TB (to prevent airway obstruction). * **Standard Regimen:** Dexamethasone or Prednisolone is typically tapered over 6–8 weeks. * **Contraindication:** Always avoid steroids in TB if the patient has not started effective Anti-Tubercular Therapy (ATT), as it can lead to uncontrolled bacterial multiplication.

Q: All of the following are indications for steroid use in Tuberculosis except?

Bone TB. The use of corticosteroids in Tuberculosis (TB) is based on the principle of reducing the detrimental host inflammatory response, which can cause tissue damage or mechanical obstruction. **Why Bone TB is the correct answer:** In **Bone and Joint TB** (including Pott’s spine), there is no evidence that steroids improve outcomes [1]. Management relies strictly on Anti-Tubercular Therapy (ATT) and, in specific cases, surgical intervention for stabilization or decompression [2]. Steroids do not prevent deformity or improve neurological recovery in these patients. **Analysis of Incorrect Options:** * **Tubercular Meningitis (TBM):** This is the most definitive indication. Steroids (Dexamethasone/Prednisolone) reduce cerebral edema, intracranial pressure, and vasculitis, significantly decreasing mortality and neurological deficits [1]. * **Pericardial Effusion:** Steroids reduce the risk of constrictive pericarditis and the need for repeated pericardiocentesis by decreasing fibrin deposition and pericardial thickening [1]. * **Massive Pleural Effusion:** While not mandatory for all pleural TB, steroids are indicated in **massive** effusions to hasten the resolution of fluid, prevent pleural thickening (fibrothorax), and alleviate severe respiratory distress. **High-Yield Clinical Pearls for NEET-PG:** 1. **Other Indications:** Adrenal TB (Addisonian crisis), Laryngeal TB (to prevent airway obstruction), and Miliary TB (if severe hypoxia/ARDS is present). 2. **IRIS:** Steroids are the treatment of choice for Paradoxical IRIS (Immune Reconstitution Inflammatory Syndrome) in HIV-TB co-infected patients. 3. **Rule of Thumb:** Steroids should **never** be given without concurrent ATT coverage to prevent uncontrolled mycobacterial replication.

Q: Significant bacteriuria is defined as the presence of which of the following number of bacteria per ml of urine?

>100,000. The concept of **Significant Bacteriuria** was established by Edward Kass to distinguish true urinary tract infection (UTI) from contamination [1]. The standard definition is the presence of **≥10⁵ (100,000) colony-forming units (CFU) per ml** of urine in a clean-catch midstream sample. This threshold provides high specificity for identifying active bacterial multiplication in the bladder [1]. * **Option D (>100,000) is Correct:** This is the classical "Kass Criteria" used to diagnose asymptomatic bacteriuria and most symptomatic UTIs. It represents a high bacterial load unlikely to be caused by skin flora contamination during voiding. * **Options A, B, and C are Incorrect:** These values (100 to 100,000 CFU/ml) are generally considered "low-count bacteriuria." While they may represent early infection or contamination, they do not meet the traditional definition of significant bacteriuria for a standard midstream sample. **High-Yield Clinical Pearls for NEET-PG:** 1. **Exceptions to the 10⁵ Rule:** In symptomatic females with cystitis, a lower threshold of **≥10² CFU/ml** (coliforms) is often considered significant. 2. **Suprapubic Aspiration:** Any growth of bacteria (even 1 CFU/ml) from a suprapubic needle aspiration is considered significant. 3. **Catheterized Patients:** In patients with indwelling catheters, a threshold of **≥10² to 10³ CFU/ml** is typically used to define infection. 4. **Asymptomatic Bacteriuria:** Requires two consecutive voided specimens with ≥10⁵ CFU/ml in females, or a single specimen in males. Treatment is only indicated in **pregnant women** and patients undergoing **urological procedures**.

Q: Which of the following is NOT a feature of cerebral malaria?

Focal neurologic deficit. **Explanation:** Cerebral malaria, caused by *Plasmodium falciparum*, is defined as a clinical syndrome characterized by coma (Glasgow Coma Scale <11 in adults) at least 1 hour after the termination of a seizure, in the presence of asexual malaria parasites on a blood film. **Why Focal Neurologic Deficit is the correct answer:** Cerebral malaria is typically a **diffuse encephalopathy**. While patients present with altered consciousness and generalized seizures, **focal neurological deficits** (such as hemiplegia or cranial nerve palsies) are **uncommon** and should prompt a search for alternative diagnoses like a brain abscess, stroke, or post-ictal state (Todd’s paralysis). **Analysis of other options:** * **Retinal Hemorrhages:** These are a classic and specific finding in cerebral malaria (malarial retinopathy). They are highly prognostic; their presence correlates with the severity of brain involvement and increased mortality. * **Extensor Plantar Reflex (Babinski Sign):** Upper motor neuron signs are common in cerebral malaria due to diffuse cortical dysfunction. An extensor plantar response is frequently observed during the comatose state. * **Absent Abdominal Reflex:** This is a common clinical finding in cerebral malaria, reflecting the involvement of the corticospinal tracts. **NEET-PG High-Yield Pearls:** * **Pathogenesis:** Sequestration of parasitized RBCs in cerebral microvasculature (cytoadherence) leading to hypoxia and cytokine release [1]. * **Drug of Choice:** Intravenous **Artesunate** is the gold standard (superior to Quinine). * **Poor Prognostic Markers:** Deep coma, retinal hemorrhages, metabolic acidosis (most important predictor of death), and hyperlactatemia. * **CSF Findings:** Usually normal or slightly elevated protein; pleocytosis is rare (helps differentiate from bacterial meningitis).

Q: What is the drug of choice for the treatment of latent syphilis?

Penicillin. Explanation: Penicillin G remains the gold standard and drug of choice for all stages of syphilis, including latent syphilis. The underlying medical concept is that Treponema pallidum is exquisitely sensitive to penicillin, and despite decades of use, no documented resistance has emerged. For latent syphilis, the goal is to prevent progression to tertiary syphilis and transmission. * Early Latent Syphilis ( 1 year or unknown duration): Treated with three weekly doses of Benzathine Penicillin G (7.2 million units total). Analysis of Incorrect Options: * B. Erythromycin: While once used, it is no longer recommended due to high rates of treatment failure and increasing resistance. It also does not reliably cross the placental barrier. * C. Tetracycline (or Doxycycline): These are considered second-line alternatives for non-pregnant, penicillin-allergic patients. However, they are less effective than penicillin and require longer courses (28 days for late latent). * D. Ciprofloxacin: Fluoroquinolones have no clinical role in the treatment of syphilis. High-Yield Clinical Pearls for NEET-PG: 1. Jarisch-Herxheimer Reaction: An acute febrile reaction occurring within 24 hours of starting penicillin; it is caused by the release of endotoxins from dying spirochetes. It is not an allergic reaction. 2. Pregnancy: Penicillin is the only acceptable treatment. If a pregnant woman is allergic, she must undergo desensitization followed by penicillin treatment. 3. Neurosyphilis: Requires Aqueous Crystalline Penicillin G (IV), as Benzathine penicillin does not achieve therapeutic levels in the CSF.

Question 1

What is a common cause of post-influenza pneumonia in a 70-year-old woman who developed flu and died one week after pneumonia?

Accepted Answer

Staphylococcus

Answer

Measles

Answer

Legionella

Answer

CMV

Question 2

Corticosteroids are absolutely contraindicated in which of the following types of tuberculosis?

Accepted Answer

Intestinal

Answer

Miliary

Answer

Meningeal

Answer

Renal

Question 3

Corticosteroids are absolutely contraindicated in which of the following types of tuberculosis?

Accepted Answer

Intestinal

Answer

Miliary

Answer

Meningeal

Answer

Renal

Question 4

According to RNTCP, tubercular pericarditis should be treated with which category of anti-tubercular regimen?

Accepted Answer

Category I

Answer

Category III

Answer

Category II

Answer

Category IV

Question 5

All of the following are indications for steroid use in Tuberculosis except?

Accepted Answer

Bone TB

Answer

Tubercular meningitis

Answer

Pericardial effusion

Answer

Massive pleural effusion

Question 6

Significant bacteriuria is defined as the presence of which of the following number of bacteria per ml of urine?

Accepted Answer

>100,000

Answer

100-1000

Answer

1000-10,000

Answer

10,000-100,000

Question 7

A 17-year-old man presents with fatigue, malaise, fever, and sore throat. He has no significant past medical history and is not on any medications. Physical examination reveals enlarged, palpable cervical lymph nodes. He reports no weight loss or night sweats. Laboratory investigations include a normal chest x-ray, negative throat swab, and an abnormal blood film with atypical lymphocytes. His hemoglobin is 15.5 g/dL; hematocrit 42%; platelets 290,000/mL; WBC 10,500/mL, with 45% segmented neutrophils, 1% eosinophils, and 54% lymphocytes, of which 36% were atypical. Which of the following is the most appropriate initial diagnostic test?

Accepted Answer

Heterophil antibody (Monospot) test

Answer

Lymph node biopsy

Answer

Bone marrow examination

Answer

Erythrocyte sedimentation rate (ESR)

Question 8

Which of the following is NOT a feature of cerebral malaria?

Accepted Answer

Focal neurologic deficit

Answer

Retinal hemorrhages

Answer

Extensor plantar reflex

Answer

Absent abdominal reflex

Question 9

What is the recommended prophylaxis for a pinprick injury in an HIV-positive individual, EXCEPT for which of the following?

Accepted Answer

Acyclovir for 12 months

Answer

Zidovudine for 4 weeks

Answer

If there is a scalpel cut wound, use Zidovudine with Stavudine and Lamivudine

Answer

Regular blood testing

Question 10

What is the drug of choice for the treatment of latent syphilis?

Accepted Answer

Penicillin

Answer

Erythromycin

Answer

Tetracycline

Answer

Ciprofloxacin

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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