Serious & Notifiable Infections — MCQs
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A 62-year-old man presents with a 10-day history of fever, headache, photophobia, and neck stiffness. Lumbar puncture shows: opening pressure 28 cmH₂O, CSF protein 3.5 g/L, glucose 1.8 mmol/L (plasma glucose 6.2 mmol/L), white cell count 320 cells/μL (85% lymphocytes). CSF Gram stain and India ink are negative. CSF tuberculosis PCR (Xpert MTB/RIF) is negative. Cryptococcal antigen is negative. He is started on empirical treatment. What additional investigation is most likely to establish the diagnosis?
A 35-year-old man with advanced HIV infection (CD4 count 25 cells/mm³, viral load 185,000 copies/mL) who is not on antiretroviral therapy presents with a 4-week history of headache, fever, and confusion. CT head shows multiple ring-enhancing lesions in the basal ganglia with surrounding oedema. Lumbar puncture is deferred. Toxoplasma serology is IgG positive. He is started on sulfadiazine, pyrimethamine, and folinic acid for presumed cerebral toxoplasmosis. After how many weeks of treatment should he have a repeat CT head to assess response, and what action should be taken if there is no improvement?
A 54-year-old man from India who moved to the UK 8 months ago presents with a 4-week history of productive cough and night sweats. Chest X-ray shows bilateral upper lobe consolidation with cavitation. Three sputum samples are positive for acid-fast bacilli on microscopy. He is started on rifampicin, isoniazid, pyrazinamide, and ethambutol. After 4 weeks of treatment, culture results become available showing Mycobacterium tuberculosis with isoniazid resistance (katG gene mutation) but sensitive to rifampicin, pyrazinamide, and ethambutol. What is the most appropriate modification to his treatment regimen?
What is the primary mechanism by which corticosteroids improve outcomes when given as adjunctive therapy in acute bacterial meningitis?
A 28-year-old healthcare worker who is 10 weeks pregnant has been exposed to a patient with smear-positive pulmonary tuberculosis during an unprotected bronchoscopy procedure. A tuberculin skin test performed shows 18 mm induration at 48 hours. Chest X-ray is normal and she is asymptomatic. What is the most appropriate management?
A 12-month-old infant is brought to the emergency department with a 6-hour history of fever, irritability, and refusing feeds. On examination, temperature is 39.5°C, heart rate 165 bpm, respiratory rate 45 breaths/minute, capillary refill time 4 seconds, and the fontanelle is bulging. The infant is lethargic but arousable. What is the most appropriate immediate antibiotic therapy before lumbar puncture?
A 45-year-old woman with chronic kidney disease stage 4 (eGFR 22 mL/min/1.73m²) is diagnosed with drug-sensitive pulmonary tuberculosis. She weighs 70 kg. What is the most appropriate modification to standard anti-tuberculous therapy for this patient?
According to UK public health guidelines, which of the following individuals exposed to a case of confirmed meningococcal meningitis requires chemoprophylaxis?
A 58-year-old man with a recent diagnosis of acute myeloid leukaemia who completed his first cycle of intensive chemotherapy 14 days ago presents with a 48-hour history of severe headache, confusion, and fever. On examination, temperature is 38.7°C, he is confused with GCS 14/15, and has mild neck stiffness. Blood tests show neutrophil count 0.2 × 10⁹/L. CT head is normal. Lumbar puncture shows: opening pressure 24 cmH₂O, CSF protein 0.9 g/L, glucose 3.1 mmol/L (plasma glucose 5.8 mmol/L), white cell count 85 cells/μL (95% lymphocytes). Gram stain is negative. What is the most appropriate empirical antimicrobial therapy while awaiting further CSF results?
A 37-year-old man from Bangladesh who has been in the UK for 2 years presents with a 3-month history of cough, fever, and weight loss. Chest X-ray shows bilateral upper lobe cavitation. Three sputum samples are smear-positive for acid-fast bacilli. GeneXpert MTB/RIF testing is positive for Mycobacterium tuberculosis with rifampicin resistance detected. What is the most appropriate initial treatment regimen?
Serious & Notifiable Infections UK Medical PG Practice Questions and MCQs
Question 121: A 62-year-old man presents with a 10-day history of fever, headache, photophobia, and neck stiffness. Lumbar puncture shows: opening pressure 28 cmH₂O, CSF protein 3.5 g/L, glucose 1.8 mmol/L (plasma glucose 6.2 mmol/L), white cell count 320 cells/μL (85% lymphocytes). CSF Gram stain and India ink are negative. CSF tuberculosis PCR (Xpert MTB/RIF) is negative. Cryptococcal antigen is negative. He is started on empirical treatment. What additional investigation is most likely to establish the diagnosis?
- A. Repeat lumbar puncture and send larger volume of CSF for tuberculosis culture (Correct Answer)
- B. Serum and CSF antibody testing for Lyme disease
- C. CSF viral PCR panel including enterovirus and herpes viruses
- D. Blood cultures for Brucella species
- E. MRI brain and spinal cord with gadolinium contrast for neurosarcoidosis
Explanation: ***Repeat lumbar puncture and send larger volume of CSF for tuberculosis culture*** - The patient presents with **subacute meningitis** and a CSF profile characterized by **lymphocytic pleocytosis**, markedly **low glucose** (hypoglycorrhachia), and very **high protein**. This combination is highly suggestive of **Tuberculous Meningitis (TBM)**. - The initial **Xpert MTB/RIF** has limited sensitivity in CSF. To confirm TBM, **Mycobacterium tuberculosis culture** from a larger volume (5-10 mL) of CSF, often obtained through **serial lumbar punctures**, is crucial as it remains the **gold standard** and significantly increases diagnostic yield. *Serum and CSF antibody testing for Lyme disease* - While **Lyme neuroborreliosis** can cause lymphocytic meningitis, it typically presents with less severe **hypoglycorrhachia** and usually involves symptoms like cranial neuropathies or radiculopathy, which are not explicitly mentioned here. - The extremely high protein and profound glucose reduction seen in this patient's CSF are less characteristic of Lyme disease and point more strongly towards a granulomatous or severe infectious process. *CSF viral PCR panel including enterovirus and herpes viruses* - **Viral meningitis** is typically associated with **normal CSF glucose** and only mild-to-moderate elevation in CSF **protein** levels, despite showing lymphocytic pleocytosis. - The severe **hypoglycorrhachia** (1.8 mmol/L) and very high **protein** (3.5 g/L) observed in this patient's CSF make common viral etiologies, such as enteroviruses and herpesviruses, highly unlikely. *Blood cultures for Brucella species* - **Neurobrucellosis** is a differential for chronic meningitis with a similar CSF profile (lymphocytic pleocytosis, low glucose, high protein), but it is geographically limited and often linked to specific **epidemiological risks** (e.g., unpasteurized dairy, animal contact). - While a possibility, **Tuberculous Meningitis** is a statistically more common and globally prevalent cause of this specific and severe CSF presentation, necessitating its primary and rigorous exclusion. *MRI brain and spinal cord with gadolinium contrast for neurosarcoidosis* - **Neurosarcoidosis** can mimic TBM by causing chronic meningitis with similar CSF findings and imaging abnormalities like basal leptomeningeal enhancement. - However, **neurosarcoidosis** is a diagnosis of exclusion. Given the highly suggestive CSF findings for a treatable and aggressive infection like TBM, infectious causes must be thoroughly ruled out first due to the urgency of treatment and risk of neurological damage.
Question 122: A 35-year-old man with advanced HIV infection (CD4 count 25 cells/mm³, viral load 185,000 copies/mL) who is not on antiretroviral therapy presents with a 4-week history of headache, fever, and confusion. CT head shows multiple ring-enhancing lesions in the basal ganglia with surrounding oedema. Lumbar puncture is deferred. Toxoplasma serology is IgG positive. He is started on sulfadiazine, pyrimethamine, and folinic acid for presumed cerebral toxoplasmosis. After how many weeks of treatment should he have a repeat CT head to assess response, and what action should be taken if there is no improvement?
- A. Repeat CT at 1 week; if no improvement, perform brain biopsy to exclude CNS lymphoma
- B. Repeat CT at 2 weeks; if no improvement, switch to second-line toxoplasmosis treatment with clindamycin and pyrimethamine
- C. Repeat CT at 2 weeks; if no improvement, perform brain biopsy to exclude alternative diagnosis such as CNS lymphoma (Correct Answer)
- D. Repeat CT at 4 weeks; if no improvement, add adjunctive corticosteroids to reduce cerebral oedema
- E. Repeat CT at 6 weeks; if no improvement, perform lumbar puncture and CSF analysis for alternative diagnoses
Explanation: ***Repeat CT at 2 weeks; if no improvement, perform brain biopsy to exclude alternative diagnosis such as CNS lymphoma*** - In advanced **HIV** patients with **multiple ring-enhancing lesions** in the basal ganglia and **Toxoplasma IgG positivity**, empirical treatment for **cerebral toxoplasmosis** is initiated. Clinical and radiological improvement is typically expected within **10-14 days** of appropriate therapy. - If there is no clinical or radiological improvement after **2 weeks** of specific anti-toxoplasmosis treatment, an **alternative diagnosis** becomes highly likely, most commonly **Primary CNS Lymphoma (PCNSL)**, necessitating a **brain biopsy** for definitive diagnosis. *Repeat CT at 1 week; if no improvement, perform brain biopsy to exclude CNS lymphoma* - A **1-week** interval is generally considered too short to reliably assess a definitive radiological response to anti-toxoplasma therapy, as significant changes may not be evident this early. - Performing an invasive **brain biopsy** prematurely at 1 week risks unnecessary procedures, as many patients will show improvement if given adequate time (up to 2 weeks). *Repeat CT at 2 weeks; if no improvement, switch to second-line toxoplasmosis treatment with clindamycin and pyrimethamine* - Failure to respond to the **first-line therapy (sulfadiazine and pyrimethamine)** for presumed toxoplasmosis in an advanced HIV patient should raise strong suspicion for an **alternative diagnosis**, rather than simply assuming drug resistance. - In this clinical scenario, especially with a very low CD4 count (<50 cells/mm³), **Primary CNS Lymphoma** is a crucial differential diagnosis that switching anti-toxoplasma drugs would delay, potentially worsening prognosis. *Repeat CT at 4 weeks; if no improvement, add adjunctive corticosteroids to reduce cerebral oedema* - Waiting **4 weeks** to reassess response in a patient with progressive neurological symptoms and an immunocompromised status is unacceptably long and could lead to significant clinical deterioration or irreversible damage. - While **corticosteroids** reduce cerebral edema, they can also cause a transient reduction in tumor size in **CNS lymphoma** (the "vanishing tumor" effect), potentially obscuring the diagnosis and making a subsequent biopsy less conclusive. *Repeat CT at 6 weeks; if no improvement, perform lumbar puncture and CSF analysis for alternative diagnoses* - A **6-week** delay for reassessment is far too long for a patient with acute neurological confusion and suspected cerebral mass lesions, increasing the risk of severe complications and delaying appropriate treatment. - **Lumbar puncture** might be contraindicated in the presence of **multiple ring-enhancing lesions** with surrounding edema and potential mass effect, as it carries a significant risk of **herniation** if there is elevated intracranial pressure.
Question 123: A 54-year-old man from India who moved to the UK 8 months ago presents with a 4-week history of productive cough and night sweats. Chest X-ray shows bilateral upper lobe consolidation with cavitation. Three sputum samples are positive for acid-fast bacilli on microscopy. He is started on rifampicin, isoniazid, pyrazinamide, and ethambutol. After 4 weeks of treatment, culture results become available showing Mycobacterium tuberculosis with isoniazid resistance (katG gene mutation) but sensitive to rifampicin, pyrazinamide, and ethambutol. What is the most appropriate modification to his treatment regimen?
- A. Continue rifampicin, pyrazinamide, and ethambutol for 2 months, then rifampicin and ethambutol for 10 months (total 12 months)
- B. Stop isoniazid, continue rifampicin, pyrazinamide, and ethambutol for 2 months, then rifampicin and ethambutol for 7 months (total 9 months)
- C. Stop isoniazid, add levofloxacin, continue rifampicin, pyrazinamide, ethambutol, and levofloxacin for 2 months, then rifampicin, ethambutol, and levofloxacin for 10 months (Correct Answer)
- D. Continue rifampicin, isoniazid, pyrazinamide, and ethambutol for full 6 months (isoniazid resistance with katG mutation does not require treatment change)
- E. Stop isoniazid, add levofloxacin, continue rifampicin, pyrazinamide, ethambutol, and levofloxacin for 6 months, then rifampicin and levofloxacin for 3 months (total 9 months)
Explanation: ***Stop isoniazid, add levofloxacin, continue rifampicin, pyrazinamide, ethambutol, and levofloxacin for 2 months, then rifampicin, ethambutol, and levofloxacin for 10 months***- For **isoniazid-resistant TB (Hr-TB)**, World Health Organization (WHO) and NICE guidelines recommend adding a **fluoroquinolone (levofloxacin)** and extending the total duration to **12 months**.- The **katG mutation** confers high-level resistance, necessitating the addition of a potent bactericidal agent like levofloxacin to prevent the development of multidrug-resistant TB (MDR-TB).*Continue rifampicin, pyrazinamide, and ethambutol for 2 months, then rifampicin and ethambutol for 10 months (total 12 months)*- While this regimen covers the extended duration, it lacks the **fluoroquinolone** needed to bolster the regimen in the absence of effective isoniazid.- Omitting the fluoroquinolone in the presence of **high-level resistance** (katG) increases the risk of treatment failure and further resistance.*Stop isoniazid, continue rifampicin, pyrazinamide, and ethambutol for 2 months, then rifampicin and ethambutol for 7 months (total 9 months)*- A **9-month regimen** without a fluoroquinolone is generally considered inadequate for high-level isoniazid-resistant strains with **extensive disease** or cavitation.- Modern protocols emphasize a **12-month duration** when treating isoniazid resistance to ensure complete sterilization of cavitary lesions.*Continue rifampicin, isoniazid, pyrazinamide, and ethambutol for full 6 months (isoniazid resistance with katG mutation does not require treatment change)*- This statement is incorrect as a **katG mutation** specifically causes **high-level resistance**, rendering isoniazid clinically ineffective.- Continuing a standard 6-month course would essentially be **triple therapy**, which is insufficient for a patient with high bacillary load and cavitation.*Stop isoniazid, add levofloxacin, continue rifampicin, pyrazinamide, ethambutol, and levofloxacin for 6 months, then rifampicin and levofloxacin for 3 months (total 9 months)*- Although this regimen correctly introduces a **fluoroquinolone**, the total duration of **9 months** is shorter than the recommended 12 months for Hr-TB.- The intensive phase for Hr-TB typically transitions after **2 months** of pyrazinamide, not 6 months, followed by a longer continuation phase.
Question 124: What is the primary mechanism by which corticosteroids improve outcomes when given as adjunctive therapy in acute bacterial meningitis?
- A. Direct antimicrobial effect through enhanced neutrophil function
- B. Reduction in blood-brain barrier permeability through stabilization of cerebrovascular endothelium
- C. Inhibition of host inflammatory response that causes vasculitis and cytotoxic oedema (Correct Answer)
- D. Enhanced penetration of antibiotics into the cerebrospinal fluid
- E. Prevention of seizures through direct neuronal membrane stabilization
Explanation: ***Inhibition of host inflammatory response that causes vasculitis and cytotoxic oedema*** - Corticosteroids, particularly **dexamethasone**, suppress the intense **inflammatory response** in the subarachnoid space, which is primarily responsible for the tissue damage in bacterial meningitis. - By reducing the release of pro-inflammatory cytokines, they mitigate **cerebral oedema**, **vasculitis**, and neuronal damage, thereby improving neurological outcomes and reducing mortality. *Direct antimicrobial effect through enhanced neutrophil function* - Corticosteroids are **immunosuppressive** and tend to inhibit, rather than enhance, **neutrophil migration** and function. - They do not possess any **direct bactericidal or bacteriostatic** properties; their role is immunomodulatory, not antimicrobial. *Reduction in blood-brain barrier permeability through stabilization of cerebrovascular endothelium* - While corticosteroids do stabilize the **blood-brain barrier** (BBB) by reducing inflammation, this is a secondary effect of their overall anti-inflammatory action. - The primary clinical benefit is derived from preventing the **downstream damage** caused by the host inflammatory response to bacterial lysis, not solely BBB stabilization. *Enhanced penetration of antibiotics into the cerebrospinal fluid* - Corticosteroids can actually **decrease antibiotic penetration** into the cerebrospinal fluid (CSF) by reducing meningeal inflammation and thus making the **blood-brain barrier less permeable**. - Despite this, the overall benefit of reducing inflammation outweighs the potential for slightly reduced antibiotic entry for certain pathogens. *Prevention of seizures through direct neuronal membrane stabilization* - Corticosteroids do not directly stabilize neuronal membranes to prevent seizures. - Their indirect role in seizure prevention is by reducing **cerebral inflammation** and oedema, which can otherwise predispose to seizure activity.
Question 125: A 28-year-old healthcare worker who is 10 weeks pregnant has been exposed to a patient with smear-positive pulmonary tuberculosis during an unprotected bronchoscopy procedure. A tuberculin skin test performed shows 18 mm induration at 48 hours. Chest X-ray is normal and she is asymptomatic. What is the most appropriate management?
- A. Rifampicin and isoniazid for 3 months started immediately
- B. Defer treatment until after delivery, then give isoniazid for 6 months
- C. Isoniazid with pyridoxine for 6 months started immediately (Correct Answer)
- D. Rifampicin, isoniazid, pyrazinamide, and ethambutol for 2 months, then rifampicin and isoniazid for 4 months
- E. Rifampicin and isoniazid for 3 months started in the second trimester
Explanation: ***Isoniazid with pyridoxine for 6 months started immediately*** - The patient has **Latent Tuberculosis Infection (LTBI)** confirmed by a **positive Tuberculin Skin Test (18 mm)**, recent high-risk exposure to smear-positive TB, and no signs of active disease (asymptomatic, normal Chest X-ray). - **Isoniazid (INH)** for 6-9 months, along with **Pyridoxine (Vitamin B6)** to prevent **peripheral neuropathy**, is the recommended regimen for LTBI in pregnant women, and immediate treatment is crucial for recent high-risk exposures. *Rifampicin and isoniazid for 3 months started immediately* - While **Rifampicin and Isoniazid for 3 months** is an alternative regimen for LTBI, **INH monotherapy** for 6-9 months is generally preferred in pregnancy due to its well-established safety profile. - Data on the safety of **rifampicin** during pregnancy is less extensive compared to isoniazid, making INH monotherapy the more conservative and often preferred choice. *Defer treatment until after delivery, then give isoniazid for 6 months* - Deferring treatment is only considered for those with **remote exposure** or low-risk LTBI; for **recent, high-risk exposure**, immediate treatment is recommended. - Pregnancy itself can increase the risk of **progression from LTBI to active tuberculosis**, and delaying treatment significantly raises the risk of maternal morbidity and congenital TB. *Rifampicin, isoniazid, pyrazinamide, and ethambutol for 2 months, then rifampicin and isoniazid for 4 months* - This is the standard **multi-drug regimen for active tuberculosis**, which the patient does not have, as indicated by a normal chest X-ray and absence of symptoms. - Using **four drugs** for LTBI is unnecessary and increases the risk of **drug toxicity**, particularly **pyrazinamide**, which has limited safety data in pregnancy and is generally avoided. *Rifampicin and isoniazid for 3 months started in the second trimester* - Although some clinicians might consider delaying treatment until the **second trimester**, for a **recent high-risk exposure**, immediate treatment is generally recommended even in the first trimester. - Delaying treatment creates a window of vulnerability for **progression to active disease** during pregnancy, which carries higher risks than immediate, appropriate LTBI therapy.
Question 126: A 12-month-old infant is brought to the emergency department with a 6-hour history of fever, irritability, and refusing feeds. On examination, temperature is 39.5°C, heart rate 165 bpm, respiratory rate 45 breaths/minute, capillary refill time 4 seconds, and the fontanelle is bulging. The infant is lethargic but arousable. What is the most appropriate immediate antibiotic therapy before lumbar puncture?
- A. Intravenous ceftriaxone 80 mg/kg
- B. Intravenous cefotaxime 50 mg/kg plus intravenous amoxicillin 50 mg/kg (Correct Answer)
- C. Intravenous benzylpenicillin 50 mg/kg
- D. Intravenous ceftriaxone 80 mg/kg plus intravenous vancomycin 15 mg/kg
- E. Intravenous cefotaxime 50 mg/kg plus intravenous aciclovir 20 mg/kg
Explanation: ***Intravenous cefotaxime 50 mg/kg plus intravenous amoxicillin 50 mg/kg*** - This combination is the preferred empirical treatment for suspected **bacterial meningitis** in infants to ensure broad coverage, including for **Listeria monocytogenes**. - Cefotaxime (a **third-generation cephalosporin**) covers common pathogens like *S. pneumoniae* and Gram-negatives, while amoxicillin specifically targets **Listeria**, crucial in infants, especially given the severe presentation. *Intravenous ceftriaxone 80 mg/kg* - Ceftriaxone is a potent third-generation cephalosporin but, as a single agent, fails to provide adequate coverage for **Listeria monocytogenes**. - In infants, particularly those under 3 months, **cefotaxime** is often preferred over ceftriaxone to avoid potential **bilirubin displacement** and kernicterus, although the risk is lower at 12 months. *Intravenous benzylpenicillin 50 mg/kg* - Benzylpenicillin primarily covers Gram-positive organisms and *Listeria* but lacks sufficient **Gram-negative coverage** (e.g., *E. coli*, *H. influenzae*). - It is generally insufficient as a sole empirical agent in the hospital setting for an infant with undifferentiated severe meningitis, especially without clear meningococcal disease indicators. *Intravenous ceftriaxone 80 mg/kg plus intravenous vancomycin 15 mg/kg* - This regimen is reserved for situations with a high suspicion of **penicillin-resistant Streptococcus pneumoniae** or in specific high-risk scenarios not indicated here. - It is not the standard first-line empirical regimen for community-acquired meningitis in this age group and **does not cover Listeria monocytogenes**. *Intravenous cefotaxime 50 mg/kg plus intravenous aciclovir 20 mg/kg* - Aciclovir is used for suspected **HSV encephalitis**, which would typically present with more focal neurological signs rather than general signs of sepsis and meningitis. - While cefotaxime covers some bacterial pathogens, the addition of aciclovir is not the immediate priority for broad empirical coverage in this critically ill infant, and this regimen still **lacks coverage for Listeria monocytogenes**.
Question 127: A 45-year-old woman with chronic kidney disease stage 4 (eGFR 22 mL/min/1.73m²) is diagnosed with drug-sensitive pulmonary tuberculosis. She weighs 70 kg. What is the most appropriate modification to standard anti-tuberculous therapy for this patient?
- A. Rifampicin 600 mg once daily, isoniazid 300 mg once daily, pyrazinamide 2 g three times weekly, ethambutol 15 mg/kg three times weekly (Correct Answer)
- B. Rifampicin 450 mg once daily, isoniazid 200 mg once daily, pyrazinamide omitted, ethambutol 15 mg/kg three times weekly
- C. Rifampicin 600 mg once daily, isoniazid 300 mg once daily, pyrazinamide omitted, ethambutol 25 mg/kg once daily
- D. Rifampicin 600 mg once daily, isoniazid 300 mg once daily, pyrazinamide 1.5 g once daily, ethambutol 15 mg/kg once daily
- E. Rifampicin 600 mg once daily, isoniazid 300 mg once daily, pyrazinamide 1.5 g once daily, moxifloxacin 400 mg once daily (avoid ethambutol)
Explanation: ***Rifampicin 600 mg once daily, isoniazid 300 mg once daily, pyrazinamide 2 g three times weekly, ethambutol 15 mg/kg three times weekly***- In patients with **eGFR < 30 mL/min**, **rifampicin** and **isoniazid** do not require dose adjustments as they are primarily metabolized by the liver.- **Pyrazinamide** and **ethambutol** require a reduction in frequency to **three times weekly** (instead of daily) to prevent toxic accumulation and side effects like **optic neuritis**.*Rifampicin 450 mg once daily, isoniazid 200 mg once daily, pyrazinamide omitted, ethambutol 15 mg/kg three times weekly*- **Rifampicin** and **isoniazid** are under-dosed here; standard dosing (600mg/300mg) should be maintained regardless of renal function for a 70 kg adult.- Omitting **pyrazinamide** unnecessarily complicates the regimen and typically requires extending the total duration of treatment to 9 months.*Rifampicin 600 mg once daily, isoniazid 300 mg once daily, pyrazinamide omitted, ethambutol 25 mg/kg once daily*- Daily dosing of **ethambutol** at 25 mg/kg in a patient with stage 4 CKD poses a very high risk of irreversible **optic neuropathy**.- There is no clinical indication to omit **pyrazinamide** in renal failure if the frequency is adjusted correctly to three times per week.*Rifampicin 600 mg once daily, isoniazid 300 mg once daily, pyrazinamide 1.5 g once daily, ethambutol 15 mg/kg once daily*- Chronic daily administration of **pyrazinamide** and **ethambutol** is contraindicated when **eGFR is below 30 mL/min** due to decreased renal clearance.- Failure to adjust the frequency to **thrice weekly** leads to significant drug accumulation and increased risk of **hepatotoxicity** and uremic symptoms.*Rifampicin 600 mg once daily, isoniazid 300 mg once daily, pyrazinamide 1.5 g once daily, moxifloxacin 400 mg once daily (avoid ethambutol)*- Standard first-line therapy (RHEZ) is preferred for **drug-sensitive tuberculosis**; **moxifloxacin** is generally reserved for drug-resistant cases or intolerance.- Maintaining daily **pyrazinamide** in this patient is inappropriate and ignores the necessary frequency adjustments required for severe **renal impairment**.
Question 128: According to UK public health guidelines, which of the following individuals exposed to a case of confirmed meningococcal meningitis requires chemoprophylaxis?
- A. A nurse who performed nasopharyngeal suctioning on the patient without wearing a face mask (Correct Answer)
- B. A medical student who examined the patient wearing gloves and an apron only
- C. A ward cleaner who cleaned the patient's room after discharge
- D. A doctor who intubated the patient wearing full PPE including FFP3 mask
- E. A relative who visited the patient for 30 minutes in hospital after antibiotic treatment had been started
Explanation: ***A nurse who performed nasopharyngeal suctioning on the patient without wearing a face mask*** - **Chemoprophylaxis** is indicated for healthcare workers who have direct, intimate exposure to **respiratory secretions** (e.g., suctioning or intubation) without using a **surgical face mask**. - This exposure carries a significant risk of **droplet transmission** from the index case to the mucosal surfaces of the healthcare worker. *A medical student who examined the patient wearing gloves and an apron only* - Routine clinical examination is not considered a high-risk exposure unless there is **significant contact** with respiratory droplets within a 1-meter range. - **Gloves and aprons** protect against contact transmission, but the absence of mask use during a standard exam does not mandate prophylaxis unless an **aerosol-generating procedure** occurred. *A ward cleaner who cleaned the patient's room after discharge* - *Neisseria meningitidis* is a fragile organism that does not survive well in the **external environment**; therefore, indirect contact via environmental surfaces is not a risk. - Prophylaxis is reserved for **close contacts** during the infectious period, not for housekeeping staff performing terminal cleaning. *A doctor who intubated the patient wearing full PPE including FFP3 mask* - Although intubation is a high-risk procedure, the use of **appropriate personal protective equipment (PPE)** effectively mitigates the risk of transmission. - If a mask (surgical or **FFP3**) is worn correctly during the procedure, the healthcare worker is not considered to have had a **significant exposure** requiring antibiotics. *A relative who visited the patient for 30 minutes in hospital after antibiotic treatment had been started* - Patients are generally considered non-infectious **24 hours after** starting appropriate systemic **antibiotic therapy** (e.g., ceftriaxone). - Prophylaxis is only indicated for household-type contacts who spent significant time with the case in the **7 days prior** to onset or for transient contacts with exposures lasting over **one hour**.
Question 129: A 58-year-old man with a recent diagnosis of acute myeloid leukaemia who completed his first cycle of intensive chemotherapy 14 days ago presents with a 48-hour history of severe headache, confusion, and fever. On examination, temperature is 38.7°C, he is confused with GCS 14/15, and has mild neck stiffness. Blood tests show neutrophil count 0.2 × 10⁹/L. CT head is normal. Lumbar puncture shows: opening pressure 24 cmH₂O, CSF protein 0.9 g/L, glucose 3.1 mmol/L (plasma glucose 5.8 mmol/L), white cell count 85 cells/μL (95% lymphocytes). Gram stain is negative. What is the most appropriate empirical antimicrobial therapy while awaiting further CSF results?
- A. Intravenous ceftriaxone and dexamethasone
- B. Intravenous ceftazidime, amikacin, and amphotericin B
- C. Intravenous meropenem, vancomycin, and aciclovir
- D. Intravenous meropenem, amikacin, and amphotericin B (Correct Answer)
- E. Intravenous ceftriaxone, vancomycin, and amphotericin B
Explanation: ***Intravenous meropenem, amikacin, and amphotericin B*** - This patient is in a state of **profound neutropenia** (neutrophils 0.2 × 10⁹/L), which increases susceptibility to **Gram-negative bacilli** (including *Pseudomonas*), ***Listeria monocytogenes***, and fungal pathogens. Meropenem covers *Pseudomonas* and *Listeria*. - The combination of **meropenem** (broad-spectrum antibacterial with good CSF penetration) and **amikacin** (potently covers Gram-negative bacteria like *Pseudomonas*) is crucial for bacterial coverage, while **amphotericin B** is essential for high-risk fungal pathogens such as *Candida* and *Cryptococcus* in this immunocompromised state. *Intravenous ceftriaxone and dexamethasone* - **Ceftriaxone** lacks adequate coverage for ***Pseudomonas aeruginosa*** and ***Listeria monocytogenes***, both of which are critical pathogens to cover empirically in a neutropenic patient with meningitis. - **Dexamethasone** is generally avoided in neutropenic patients with meningitis as it can further compromise the immune system and is primarily indicated for *Streptococcus pneumoniae* in immunocompetent individuals. *Intravenous ceftazidime, amikacin, and amphotericin B* - While **ceftazidime** provides good coverage for *Pseudomonas*, it lacks activity against ***Listeria monocytogenes***, which is a significant pathogen in immunocompromised patients, including those with neutropenia. - **Meropenem** is generally preferred over ceftazidime in this setting due to its broader spectrum of activity, including better coverage for *Listeria* and some anaerobic bacteria. *Intravenous meropenem, vancomycin, and aciclovir* - **Aciclovir** is an antiviral agent targeting HSV encephalitis; however, in a neutropenic patient with lymphocytic pleocytosis, fungal or severe bacterial infections (including *Listeria*) are more concerning and require broader empirical coverage than what aciclovir provides. - This regimen critically **lacks empirical antifungal coverage**, which is mandatory for a severely neutropenic patient presenting with signs of central nervous system infection. *Intravenous ceftriaxone, vancomycin, and amphotericin B* - **Ceftriaxone** is not suitable for neutropenic meningitis due to its lack of reliable coverage against ***Pseudomonas aeruginosa*** and ***Listeria monocytogenes***. - While vancomycin covers MRSA and amphotericin B covers fungi, the significant risk of **Gram-negative bacterial infection** (especially *Pseudomonas*) associated with post-chemotherapy neutropenia is not adequately addressed by ceftriaxone.
Question 130: A 37-year-old man from Bangladesh who has been in the UK for 2 years presents with a 3-month history of cough, fever, and weight loss. Chest X-ray shows bilateral upper lobe cavitation. Three sputum samples are smear-positive for acid-fast bacilli. GeneXpert MTB/RIF testing is positive for Mycobacterium tuberculosis with rifampicin resistance detected. What is the most appropriate initial treatment regimen?
- A. Isoniazid, pyrazinamide, ethambutol, and levofloxacin for 2 months, then isoniazid and ethambutol for 10 months
- B. Refer to specialist MDR-TB service for individualized treatment regimen based on full drug susceptibility testing (Correct Answer)
- C. Rifampicin, isoniazid, pyrazinamide, and ethambutol for 2 months, then rifampicin and isoniazid for 4 months
- D. Bedaquiline, linezolid, levofloxacin, cycloserine, and clofazimine for 9-12 months
- E. Streptomycin, isoniazid, pyrazinamide, and ethambutol for 2 months, then isoniazid and ethambutol for 16 months
Explanation: ***Refer to specialist MDR-TB service for individualized treatment regimen based on full drug susceptibility testing*** - Detection of **rifampicin resistance** on GeneXpert is a critical marker for **multidrug-resistant tuberculosis (MDR-TB)**, requiring urgent referral to specialized services. - Management of RR-TB/MDR-TB is complex and must be tailored based on **full drug susceptibility testing (DST)** to ensure an effective and safe drug combination. *Isoniazid, pyrazinamide, ethambutol, and levofloxacin for 2 months, then isoniazid and ethambutol for 10 months* - This is an outdated approach for isoniazid monoresistance; it is insufficient when **rifampicin resistance** is confirmed. - Starting treatment without a specialist's guidance in this context risks the development of further **drug resistance**. *Rifampicin, isoniazid, pyrazinamide, and ethambutol for 2 months, then rifampicin and isoniazid for 4 months* - This is the standard 6-month regimen for **drug-sensitive tuberculosis**, which will fail in a patient with confirmed **rifampicin resistance**. - Using this regimen in the presence of resistance poses a high risk of clinical failure and the ongoing **transmission** of resistant strains. *Bedaquiline, linezolid, levofloxacin, cycloserine, and clofazimine for 9-12 months* - While these are components of modern **MDR-TB regimens**, the specific combination should not be started empirically before **full DST** results are available. - Treatment selection must be supervised by a specialist to manage the high risk of **toxicity** and ensure compliance with the latest WHO/NICE guidelines. *Streptomycin, isoniazid, pyrazinamide, and ethambutol for 2 months, then isoniazid and ethambutol for 16 months* - **Streptomycin** is rarely used in modern first-line practice due to the risk of **ototoxicity** and nephrotoxicity. - This regimen lacks a potent rifamycin or a modern MDR-TB backbone, making it inappropriate for treating **rifampicin-resistant** organisms.
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