Serious & Notifiable Infections — MCQs
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A 56-year-old woman with type 2 diabetes and chronic kidney disease (eGFR 25 mL/min/1.73m²) is diagnosed with drug-sensitive pulmonary tuberculosis. She weighs 55 kg. Standard four-drug therapy is commenced. Which aspect of her treatment requires the most careful monitoring and adjustment?
A 14-year-old girl presents to the emergency department with a 4-hour history of fever, severe headache, and vomiting. On examination, she has a temperature of 39.2°C, Glasgow Coma Scale 14/15, photophobia, and neck stiffness. There is a petechial rash on her trunk and limbs. While preparing for lumbar puncture, she becomes increasingly drowsy with a GCS of 10/15. What is the most appropriate immediate management?
A 39-year-old man who recently returned from visiting relatives in India for 3 months presents with a 6-week history of productive cough and weight loss. Chest X-ray shows right upper lobe cavitation. Sputum is smear-positive for acid-fast bacilli. Culture grows Mycobacterium tuberculosis fully sensitive to first-line drugs. He is started on rifampicin, isoniazid, pyrazinamide, and ethambutol. After 2 months, which is the appropriate continuation phase regimen?
A 71-year-old man with Parkinson's disease presents with a 4-day history of fever, confusion, and photophobia. CT head shows no contraindication to lumbar puncture. LP shows: opening pressure 18 cmH2O, white cells 85 cells/mm³ (75% lymphocytes), protein 1.2 g/L, glucose 3.1 mmol/L (plasma 5.4 mmol/L). CSF Gram stain and bacterial culture are negative. CSF PCR is positive for herpes simplex virus type 1. He has been receiving intravenous aciclovir for 3 days. What is the recommended total duration of aciclovir treatment?
A 33-year-old woman who is 28 weeks pregnant presents with a 5-week history of cough, weight loss, and night sweats. Chest X-ray shows bilateral upper zone infiltrates with cavitation. Sputum samples are smear-positive for acid-fast bacilli. GeneXpert confirms Mycobacterium tuberculosis susceptible to rifampicin. What is the most appropriate initial treatment regimen?
A 62-year-old man with chronic liver disease due to alcohol presents with fever, headache, and neck stiffness. Lumbar puncture shows: white cells 1200 cells/mm³ (85% neutrophils), protein 2.4 g/L, glucose 1.8 mmol/L (plasma 6.2 mmol/L). Blood cultures grow Gram-positive rods that are beta-haemolytic. Which antibiotic regimen should have been included in his initial empirical therapy?
A 19-year-old university student is admitted with suspected meningococcal meningitis. Blood cultures subsequently grow Neisseria meningitidis serogroup W. He makes a full recovery after treatment. Which of the following groups requires chemoprophylaxis?
A 41-year-old woman presents with a 4-week history of productive cough, fever, and night sweats. Chest X-ray shows right upper lobe consolidation with cavitation. Three sputum samples are positive for acid-fast bacilli. GeneXpert MTB/RIF detects Mycobacterium tuberculosis with rifampicin resistance. While awaiting full drug sensitivity results, which treatment regimen should be commenced?
A 54-year-old man with HIV infection (CD4 count 45 cells/mm³) presents with a 3-week history of worsening headache and fever. CT head with contrast shows multiple ring-enhancing lesions in both cerebral hemispheres. Lumbar puncture is deferred due to mass effect. He is started on pyrimethamine, sulfadiazine, and folinic acid for presumed cerebral toxoplasmosis. After how many weeks should clinical and radiological response be assessed to determine if this diagnosis is correct?
A 27-year-old woman presents with headache, fever, and confusion. Lumbar puncture shows: opening pressure 28 cmH2O, white cells 450 cells/mm³ (70% neutrophils), protein 1.8 g/L, glucose 1.2 mmol/L (plasma glucose 5.5 mmol/L). Gram stain shows Gram-positive diplococci. She is started on appropriate antimicrobial therapy. What additional treatment is most likely to improve her neurological outcome?
Serious & Notifiable Infections UK Medical PG Practice Questions and MCQs
Question 191: A 56-year-old woman with type 2 diabetes and chronic kidney disease (eGFR 25 mL/min/1.73m²) is diagnosed with drug-sensitive pulmonary tuberculosis. She weighs 55 kg. Standard four-drug therapy is commenced. Which aspect of her treatment requires the most careful monitoring and adjustment?
- A. Reduce rifampicin dose by 50% due to renal impairment
- B. Monitor visual acuity monthly due to increased risk of ethambutol toxicity (Correct Answer)
- C. Increase pyrazinamide dose to compensate for renal excretion
- D. Reduce isoniazid frequency to three times weekly
- E. Monitor liver function weekly due to increased hepatotoxicity risk
Explanation: ***Monitor visual acuity monthly due to increased risk of ethambutol toxicity***- **Ethambutol** is primarily cleared by the **kidneys**; in patients with an eGFR of 25 mL/min/1.73m², the drug accumulates, significantly increasing the risk of **optic neuropathy**.- Monthly monitoring of **visual acuity** and **color vision** is essential to detect early signs of retrobulbar neuritis, and the dosing frequency should be adjusted (e.g., to three times weekly) in severe renal impairment.*Reduce rifampicin dose by 50% due to renal impairment*- **Rifampicin** is metabolized predominantly by the **liver** and excreted primarily through the biliary system, thus requiring no dose adjustment in patients with **renal impairment**.- Standard **weight-based dosing** of rifampicin should be maintained to ensure optimal therapeutic efficacy and prevent the emergence of **drug resistance**.*Increase pyrazinamide dose to compensate for renal excretion*- **Pyrazinamide** metabolites are renally excreted; therefore, in severe **renal impairment**, the dose should be **decreased** or the interval extended (e.g., three times weekly) to prevent drug accumulation and toxicity.- Increasing the dose would be dangerous, potentially leading to severe **hyperuricemia**, gout, and heightened **hepatotoxicity**.*Reduce isoniazid frequency to three times weekly*- **Isoniazid** is primarily metabolized in the **liver** via acetylation and its elimination is largely unaffected by **chronic kidney disease**.- While **pyridoxine (Vitamin B6)** supplementation is crucial to prevent peripheral neuropathy, the standard daily dosing of isoniazid generally remains appropriate in renal impairment.*Monitor liver function weekly due to increased hepatotoxicity risk*- While **hepatotoxicity** is a known risk with anti-TB regimens (especially isoniazid and pyrazinamide), chronic kidney disease is not typically an independent factor that necessitates *weekly* liver function monitoring over standard protocols.- The most immediate and specific drug-related toxicity requiring heightened vigilance in this patient, given her **eGFR of 25 mL/min/1.73m²**, is the renal accumulation of **ethambutol** and its associated **optic neuropathy**.
Question 192: A 14-year-old girl presents to the emergency department with a 4-hour history of fever, severe headache, and vomiting. On examination, she has a temperature of 39.2°C, Glasgow Coma Scale 14/15, photophobia, and neck stiffness. There is a petechial rash on her trunk and limbs. While preparing for lumbar puncture, she becomes increasingly drowsy with a GCS of 10/15. What is the most appropriate immediate management?
- A. Proceed immediately with lumbar puncture before administering antibiotics
- B. Arrange urgent CT head before lumbar puncture or antibiotics
- C. Administer intravenous ceftriaxone immediately and defer lumbar puncture (Correct Answer)
- D. Administer intravenous dexamethasone followed by antibiotics and perform LP when stable
- E. Perform blood cultures, then lumbar puncture, then administer antibiotics
Explanation: ***Administer intravenous ceftriaxone immediately and defer lumbar puncture*** - The patient presents with classic signs of **meningitis** and **meningococcemia** (fever, headache, neck stiffness, photophobia, petechial rash). The **declining GCS** (from 14 to 10) indicates rapid neurological deterioration and potential **raised intracranial pressure** or impending herniation. - In cases of suspected bacterial meningitis with signs of raised intracranial pressure (e.g., declining GCS), **empirical broad-spectrum antibiotics** (like ceftriaxone) are the **highest priority** and should be administered immediately without delay for a lumbar puncture or CT scan. Lumbar puncture is contraindicated in this scenario due to the risk of **herniation**. *Proceed immediately with lumbar puncture before administering antibiotics* - Performing a **lumbar puncture** in a patient with a **rapidly deteriorating GCS** and signs highly suggestive of bacterial meningitis with complications like raised ICP or impending herniation is **contraindicated**. - This approach risks **brainstem herniation**, a fatal complication, and inappropriately delays the administration of **life-saving antibiotics**. *Arrange urgent CT head before lumbar puncture or antibiotics* - While a **CT head** is indicated to rule out mass lesions or severe edema before an LP in a patient with reduced consciousness, obtaining it must **not delay** the immediate administration of **empirical antibiotics**. - Delaying antibiotics for imaging significantly increases **morbidity and mortality** in bacterial meningitis, especially with signs of **septic shock** or rapid deterioration. *Administer intravenous dexamethasone followed by antibiotics and perform LP when stable* - While **dexamethasone** is often co-administered with antibiotics in bacterial meningitis to reduce inflammation and neurological sequelae, it is **not the absolute immediate priority** over bactericidal antibiotics. - The most critical first step for a patient in **septic shock** or with rapidly progressing meningitis is the prompt administration of **antibiotics**, which should not be delayed by other treatments. *Perform blood cultures, then lumbar puncture, then administer antibiotics* - While **blood cultures** are important for identifying the causative organism and guiding specific antibiotic therapy, they should **not significantly delay** the administration of empirical antibiotics in a critically ill patient. - This sequence is incorrect because the **lumbar puncture** is contraindicated by the patient's neurological deterioration, and delaying antibiotics for either cultures or LP is dangerous.
Question 193: A 39-year-old man who recently returned from visiting relatives in India for 3 months presents with a 6-week history of productive cough and weight loss. Chest X-ray shows right upper lobe cavitation. Sputum is smear-positive for acid-fast bacilli. Culture grows Mycobacterium tuberculosis fully sensitive to first-line drugs. He is started on rifampicin, isoniazid, pyrazinamide, and ethambutol. After 2 months, which is the appropriate continuation phase regimen?
- A. Rifampicin and isoniazid for 4 months (Correct Answer)
- B. Rifampicin, isoniazid, and ethambutol for 4 months
- C. Rifampicin, isoniazid, and pyrazinamide for 4 months
- D. Rifampicin and isoniazid for 7 months
- E. Rifampicin, isoniazid, pyrazinamide, and ethambutol for 4 months
Explanation: ***Rifampicin and isoniazid for 4 months*** - For **drug-sensitive pulmonary tuberculosis**, the standard regimen consists of a 2-month **intensive phase** (RHZE) followed by a 4-month **continuation phase** using only **rifampicin and isoniazid**. - Since the isolate is **fully sensitive** and the patient is completing the initial 2-month phase with full sensitivity to first-line drugs, the continuation phase aims to eliminate remaining bacilli while minimizing toxicity. *Rifampicin, isoniazid, and ethambutol for 4 months* - **Ethambutol** is primarily included in the initial intensive phase to prevent the development of resistance in case of unknown susceptibility. - Once the TB strain is confirmed to be **fully sensitive** to rifampicin and isoniazid, ethambutol is discontinued to reduce the risk of adverse effects like **optic neuritis**. *Rifampicin, isoniazid, and pyrazinamide for 4 months* - **Pyrazinamide** is critical for its early sterilizing activity, especially against intracellular bacilli in acidic environments, during the first 2 months. - Continuing pyrazinamide beyond 2 months is not recommended for drug-sensitive TB due to an increased risk of **hepatotoxicity** and **hyperuricemia** without significant additional therapeutic benefit. *Rifampicin and isoniazid for 7 months* - A **7-month continuation phase** (total 9 months of treatment) is typically reserved for specific high-risk scenarios, such as extensive cavitary disease that remains **culture-positive** at the end of the 2-month intensive phase, or certain forms of **extrapulmonary TB** (e.g., bone/joint or CNS TB). - For standard drug-sensitive **pulmonary tuberculosis** responding well, a total treatment duration of 6 months (2 intensive + 4 continuation) is highly effective and the standard of care. *Rifampicin, isoniazid, pyrazinamide, and ethambutol for 4 months* - Continuing the full **quadruple therapy** (RHZE) for the entire 6 months is not necessary for drug-sensitive tuberculosis and significantly increases the **pill burden** and the risk of drug-related adverse effects. - The standard guidelines recommend de-escalating to a two-drug regimen (rifampicin and isoniazid) in the continuation phase once drug sensitivity is confirmed.
Question 194: A 71-year-old man with Parkinson's disease presents with a 4-day history of fever, confusion, and photophobia. CT head shows no contraindication to lumbar puncture. LP shows: opening pressure 18 cmH2O, white cells 85 cells/mm³ (75% lymphocytes), protein 1.2 g/L, glucose 3.1 mmol/L (plasma 5.4 mmol/L). CSF Gram stain and bacterial culture are negative. CSF PCR is positive for herpes simplex virus type 1. He has been receiving intravenous aciclovir for 3 days. What is the recommended total duration of aciclovir treatment?
- A. 5 days
- B. 7 days
- C. 10 days
- D. 14 days (Correct Answer)
- E. 21 days
Explanation: ***14 days*** - For confirmed **Herpes Simplex Virus (HSV) encephalitis** in an immunocompetent adult, current guidelines recommend a minimum duration of **14 to 21 days** of intravenous **aciclovir**. - This extended duration is crucial for eradicating the virus from the central nervous system, reducing severe neurological sequelae, and preventing **relapse**. *5 days* - A **5-day** course of **aciclovir** is typically inadequate for treating **HSV encephalitis**, a severe central nervous system infection. - This shorter duration is usually reserved for less severe mucocutaneous **herpes simplex virus** infections. *7 days* - A **7-day** course of **aciclovir** is the standard treatment for **HSV meningitis**, which usually has a more benign course and less direct parenchymal involvement than encephalitis. - For **encephalitis**, which involves inflammation of the brain parenchyma, a significantly longer duration is required to ensure viral clearance and improve outcomes. *10 days* - While longer than 5 or 7 days, a **10-day** course of **aciclovir** is generally considered insufficient for the treatment of **HSV encephalitis**. - Evidence suggests that a treatment duration of at least **14 days** is necessary to achieve optimal clinical response and minimize the risk of long-term neurological deficits. *21 days* - A **21-day** course of **aciclovir** is typically reserved for specific situations such as **neonatal HSV infection** or in severely **immunocompromised patients** with HSV encephalitis. - For the majority of immunocompetent adults, while a longer course might be considered in very severe or recalcitrant cases, **14 days** is generally sufficient and the established minimum standard.
Question 195: A 33-year-old woman who is 28 weeks pregnant presents with a 5-week history of cough, weight loss, and night sweats. Chest X-ray shows bilateral upper zone infiltrates with cavitation. Sputum samples are smear-positive for acid-fast bacilli. GeneXpert confirms Mycobacterium tuberculosis susceptible to rifampicin. What is the most appropriate initial treatment regimen?
- A. Rifampicin, isoniazid, and ethambutol (defer pyrazinamide until after delivery)
- B. Rifampicin, isoniazid, pyrazinamide, and ethambutol (Correct Answer)
- C. Rifampicin and isoniazid only (defer other agents until after delivery)
- D. Levofloxacin, ethambutol, and cycloserine (defer rifampicin until after delivery)
- E. Defer all treatment until after delivery to minimise fetal risk
Explanation: ***Rifampicin, isoniazid, pyrazinamide, and ethambutol*** - The standard **four-drug regimen** (RIPE) is recommended for pregnant women because untreated tuberculosis poses a high risk of **maternal mortality**, fetal growth restriction, and **vertical transmission**. - All four first-line agents are considered **safe and non-teratogenic** during pregnancy; pyridoxine (vitamin B6) should be added to prevent **isoniazid-induced peripheral neuropathy**. *Rifampicin, isoniazid, and ethambutol (defer pyrazinamide until after delivery)* - Deferring **pyrazinamide** is unnecessary and results in a less effective regimen that would require a longer duration of treatment (9 months instead of 6). - Current **WHO and UK guidelines** confirm that pyrazinamide is safe for the fetus and essential for a rapid cure, especially in cavitary disease. *Rifampicin and isoniazid only (defer other agents until after delivery)* - Using only two drugs for active tuberculosis is inadequate and significantly increases the risk of developing **multidrug-resistant TB (MDR-TB)**. - An intensive phase with four drugs is mandatory to manage the high **bacillary load** typical of smear-positive, cavitary tuberculosis. *Levofloxacin, ethambutol, and cycloserine (defer rifampicin until after delivery)* - **Fluoroquinolones** like levofloxacin and second-line agents like **cycloserine** are usually avoided in pregnancy unless the patient has drug-resistant TB, which is not indicated here. - **Rifampicin** is a cornerstone of first-line therapy and should never be deferred in drug-susceptible cases as it is safe and highly effective. *Defer all treatment until after delivery to minimise fetal risk* - Delaying treatment is contraindicated as active, smear-positive TB is a life-threatening condition for the mother and a major hazard for **congenital TB**. - The risks associated with **untreated tuberculosis** far outweigh the potential adverse effects of the standard first-line antibiotic treatment.
Question 196: A 62-year-old man with chronic liver disease due to alcohol presents with fever, headache, and neck stiffness. Lumbar puncture shows: white cells 1200 cells/mm³ (85% neutrophils), protein 2.4 g/L, glucose 1.8 mmol/L (plasma 6.2 mmol/L). Blood cultures grow Gram-positive rods that are beta-haemolytic. Which antibiotic regimen should have been included in his initial empirical therapy?
- A. Ceftriaxone and vancomycin
- B. Ceftriaxone and amoxicillin (Correct Answer)
- C. Benzylpenicillin and chloramphenicol
- D. Ceftriaxone and metronidazole
- E. Meropenem and gentamicin
Explanation: ***Ceftriaxone and amoxicillin*** - The patient has bacterial meningitis caused by **Listeria monocytogenes**, indicated by **Gram-positive rods** and **beta-haemolysis** in an immunocompromised host (chronic liver disease). - **Amoxicillin** (or ampicillin) must be added to standard therapy because **Listeria** is inherently resistant to all **cephalosporins**, including ceftriaxone. *Ceftriaxone and vancomycin* - This combination is standard empirical therapy for adults to cover **Streptococcus pneumoniae** and **Neisseria meningitidis**. - It lacks coverage for **Listeria monocytogenes**, which is a critical pathogen in patients over 50 or those with **chronic liver disease**. *Benzylpenicillin and chloramphenicol* - **Benzylpenicillin** is used for meningococcal disease but does not provide the broad-spectrum coverage required for empirical management of unknown bacterial meningitis. - **Chloramphenicol** is an alternative for **Listeria** in penicillin-allergic patients but is not part of the first-line empirical regimen in this clinical setting. *Ceftriaxone and metronidazole* - **Metronidazole** provides coverage against **anaerobes**, which are typically associated with **brain abscesses** rather than primary bacterial meningitis. - This regimen fails to address the **Gram-positive rods** (Listeria) identified in the patient's cultures. *Meropenem and gentamicin* - **Meropenem** has broad activity but **amoxicillin** remains the preferred agent for **Listeria** coverage in standard meningitis protocols. - **Gentamicin** is sometimes added for synergy in confirmed Listeria cases but is not the primary empirical partner for **ceftriaxone** in meningitis guidelines.
Question 197: A 19-year-old university student is admitted with suspected meningococcal meningitis. Blood cultures subsequently grow Neisseria meningitidis serogroup W. He makes a full recovery after treatment. Which of the following groups requires chemoprophylaxis?
- A. All students living in the same university accommodation block
- B. Only household contacts who have had direct contact with oral secretions (Correct Answer)
- C. Healthcare workers who performed the initial clinical assessment without aerosol-generating procedures
- D. All laboratory staff who handled the blood culture samples
- E. Students who attended the same lectures in the 7 days before admission
Explanation: ***Only household contacts who have had direct contact with oral secretions***- **Chemoprophylaxis** is indicated for **close contacts** who have had prolonged or significant exposure to **respiratory secretions** within 7 days prior to symptom onset.- This includes **household members** or individuals with **significant transient contact** involving oral secretions, such as **intimate kissing** or sharing items contaminated with saliva.*All students living in the same university accommodation block*- **Mass prophylaxis** for an entire accommodation block is not generally recommended due to low transmission risk among those without prolonged intimate contact.- Public health guidelines prioritize **identified close contacts** (e.g., roommates) to prevent unnecessary **antibiotic use** and potential **resistance**.*Healthcare workers who performed the initial clinical assessment without aerosol-generating procedures*- Routine clinical assessment with standard precautions does not constitute a high-risk exposure for **Neisseria meningitidis** transmission to healthcare workers.- **Prophylaxis** for staff is typically reserved for direct exposure to **respiratory droplets** during **aerosol-generating procedures** (e.g., intubation) without proper **Personal Protective Equipment (PPE)**.*All laboratory staff who handled the blood culture samples*- Laboratory personnel are not routinely indicated for prophylaxis unless they experience a **laboratory accident** involving significant aerosol generation.- Adherence to **Standard Microbiological Practices** and the use of **Class II biological safety cabinets** effectively minimizes risk during routine blood culture handling.*Students who attended the same lectures in the 7 days before admission*- Attending the same lecture does not involve the **prolonged, close personal contact** necessary for **Neisseria meningitidis** transmission via large respiratory droplets.- **Neisseria meningitidis** is fragile and has poor survival outside the human host, making transmission in a **general lecture hall setting** highly unlikely.
Question 198: A 41-year-old woman presents with a 4-week history of productive cough, fever, and night sweats. Chest X-ray shows right upper lobe consolidation with cavitation. Three sputum samples are positive for acid-fast bacilli. GeneXpert MTB/RIF detects Mycobacterium tuberculosis with rifampicin resistance. While awaiting full drug sensitivity results, which treatment regimen should be commenced?
- A. Rifampicin, isoniazid, pyrazinamide, and ethambutol
- B. Isoniazid, pyrazinamide, ethambutol, and moxifloxacin
- C. Levofloxacin, bedaquiline, linezolid, and cycloserine (Correct Answer)
- D. Isoniazid, rifampicin, pyrazinamide, ethambutol, and levofloxacin
- E. Moxifloxacin, bedaquiline, pretomanid, and linezolid
Explanation: ***Levofloxacin, bedaquiline, linezolid, and cycloserine*** - Patients with **rifampicin-resistant TB (RR-TB)** detected by **GeneXpert** are treated similarly to **MDR-TB** patients, as rifampicin resistance is a strong surrogate for isoniazid resistance. - **WHO guidelines** recommend an initial MDR regimen consisting of a **fluoroquinolone** (e.g., levofloxacin), **bedaquiline**, **linezolid**, and a fourth agent like **cycloserine** while awaiting comprehensive drug susceptibility testing (DST). *Rifampicin, isoniazid, pyrazinamide, and ethambutol* - This is the standard first-line **RIPE** regimen for drug-sensitive TB, which is contraindicated once **rifampicin resistance** is confirmed. - Continuing **rifampicin** in the presence of known resistance risks clinical failure and the development of further resistance to other first-line drugs. *Isoniazid, pyrazinamide, ethambutol, and moxifloxacin* - This regimen is inadequate because it assumes the patient remains sensitive to **isoniazid**, despite the high correlation between rifampicin resistance and **isoniazid resistance**. - Relying on **ethambutol** and **pyrazinamide** as the primary backbone is insufficient for treating cavitation and high bacterial loads in confirmed **RR-TB**. *Isoniazid, rifampicin, pyrazinamide, ethambutol, and levofloxacin* - Adding a **fluoroquinolone** to a failing first-line regimen does not overcome the resistance to **rifampicin** and likely resistance to **isoniazid**. - This approach violates the core principle of TB management: never add a single drug to a **failing or resistant regimen**. *Moxifloxacin, bedaquiline, pretomanid, and linezolid* - While the **BPaLM** regimen is a modern shorter treatment for MDR-TB, it typically requires confirmation of sensitivity patterns and compliance with specific national protocols. - In many clinical settings, the longer empirical MDR-TB regimen involving **levofloxacin**, **bedaquiline**, and **linezolid** remains the standard starting point until full DST results are provided.
Question 199: A 54-year-old man with HIV infection (CD4 count 45 cells/mm³) presents with a 3-week history of worsening headache and fever. CT head with contrast shows multiple ring-enhancing lesions in both cerebral hemispheres. Lumbar puncture is deferred due to mass effect. He is started on pyrimethamine, sulfadiazine, and folinic acid for presumed cerebral toxoplasmosis. After how many weeks should clinical and radiological response be assessed to determine if this diagnosis is correct?
- A. 1 week
- B. 2 weeks (Correct Answer)
- C. 4 weeks
- D. 6 weeks
- E. 8 weeks
Explanation: ***2 weeks***- Guidelines recommend a trial of **empirical therapy** with pyrimethamine and sulfadiazine, with a formal clinical and radiological reassessment after **14 days**.- A documented improvement in symptoms and a reduction in the size of **ring-enhancing lesions** at this interval confirms the diagnosis and avoids the need for an invasive **brain biopsy**.*1 week*- Assessing at seven days is generally considered **too early** to observe definitive radiological changes in mass effect or lesion size.- While clinical stabilization may begin, a lack of significant change at this stage does not provide enough evidence to rule out **toxoplasmosis**.*4 weeks*- Delaying reassessment to one month risks allowing the progression of alternative diagnoses, such as **Primary CNS Lymphoma (PCNSL)**.- Early intervention for non-responding lesions is critical in **severely immunocompromised** patients with low CD4 counts.*6 weeks*- This duration is closer to the completion of the **acute phase** of treatment rather than the initial diagnostic reassessment phase.- Waiting this long for radiological confirmation would be clinically inappropriate if the patient is actually suffering from **malignancy** or **fungal abscesses**.*8 weeks*- An eight-week interval is typically associated with the transition to **maintenance therapy** (secondary prophylaxis) rather than diagnostic evaluation.- High mortality rates in **AIDS-related CNS infections** necessitate much earlier diagnostic confirmation to adjust the treatment plan if necessary.
Question 200: A 27-year-old woman presents with headache, fever, and confusion. Lumbar puncture shows: opening pressure 28 cmH2O, white cells 450 cells/mm³ (70% neutrophils), protein 1.8 g/L, glucose 1.2 mmol/L (plasma glucose 5.5 mmol/L). Gram stain shows Gram-positive diplococci. She is started on appropriate antimicrobial therapy. What additional treatment is most likely to improve her neurological outcome?
- A. Intravenous dexamethasone 10 mg six-hourly for 4 days (Correct Answer)
- B. Intravenous mannitol 20% 100 mL
- C. Therapeutic lumbar puncture to reduce CSF pressure
- D. Intravenous immunoglobulin 2 g/kg over 5 days
- E. Oral acetazolamide 250 mg twice daily
Explanation: ***Intravenous dexamethasone 10 mg six-hourly for 4 days*** - Adjunctive **corticosteroids**, specifically **dexamethasone**, are recommended in adults with **bacterial meningitis**, especially when caused by **Streptococcus pneumoniae**, to reduce inflammation and improve neurological outcomes like hearing loss. - For optimal benefit, dexamethasone should be administered **concomitantly with or just before** the first dose of antibiotics to mitigate the inflammatory response triggered by bacterial lysis. *Intravenous mannitol 20% 100 mL* - **Mannitol** is an osmotic diuretic used for acute management of **severely elevated intracranial pressure** and cerebral edema, but it does not improve long-term neurological outcomes in bacterial meningitis. - Its use is typically reserved for critical situations with impending herniation and is not a routine adjunctive treatment for improving overall outcome in bacterial meningitis. *Therapeutic lumbar puncture to reduce CSF pressure* - While the opening pressure is elevated, **repeated therapeutic lumbar punctures** are not a standard or recommended treatment for managing intracranial pressure in acute bacterial meningitis. - This approach carries risks, including **brain herniation** if there is significant mass effect or obstructive hydrocephalus, and does not address the underlying inflammation effectively. *Intravenous immunoglobulin 2 g/kg over 5 days* - **Intravenous immunoglobulin (IVIG)** is primarily used in certain immunodeficiency states, autoimmune conditions, or severe sepsis/toxic shock syndrome, but it has **no proven role** in improving neurological outcomes in bacterial meningitis. - There is no evidence to support its routine use as an adjunctive therapy for acute bacterial meningitis. *Oral acetazolamide 250 mg twice daily* - **Acetazolamide** is a carbonic anhydrase inhibitor that reduces CSF production and is used in conditions like **idiopathic intracranial hypertension** or certain types of hydrocephalus. - It is not indicated for the acute management of elevated intracranial pressure or inflammation in **bacterial meningitis** and would be too slow-acting and insufficient for this severe condition.
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