A 38-year-old homeless man with alcohol dependency is diagnosed with smear-positive pulmonary tuberculosis. He has a history of poor treatment adherence for other medical conditions. Molecular testing shows fully sensitive Mycobacterium tuberculosis. He is started on standard four-drug therapy. What is the most appropriate strategy to optimize treatment completion in this patient?
Q52
A 25-year-old woman is investigated for persistent headache. She is found to have a CSF opening pressure of 28 cm H₂O. The CSF shows: white cells 8/mm³ (all lymphocytes), protein 0.65 g/L, glucose 2.9 mmol/L (plasma glucose 5.2 mmol/L). Gram stain, India ink stain, and routine bacterial culture are negative. She was born in Hong Kong and moved to the UK at age 5. She works as a teacher and is in good general health with no weight loss or fever. What investigation is most likely to establish the diagnosis?
Q53
A 58-year-old man with newly diagnosed sputum smear-positive pulmonary tuberculosis is started on rifampicin 600 mg daily, isoniazid 300 mg daily, pyrazinamide 2000 mg daily, and ethambutol 1200 mg daily. His baseline investigations show: ALT 38 U/L, bilirubin 14 µmol/L, creatinine 105 µmol/L, eGFR 68 mL/min/1.73m². He weighs 95 kg. Two weeks into treatment, repeat blood tests show: ALT 165 U/L, bilirubin 18 µmol/L. He is asymptomatic. What is the most appropriate management?
Q54
A 12-year-old boy presents to the emergency department with an 8-hour history of fever, severe headache, and vomiting. On examination, temperature is 38.7°C, heart rate 125 bpm, blood pressure 95/60 mmHg, GCS 14/15. There is neck stiffness but no rash. A senior clinician performs lumbar puncture which shows: clear CSF, white cells 180/mm³ (65% lymphocytes, 35% neutrophils), protein 0.8 g/L, glucose 3.2 mmol/L (plasma glucose 5.8 mmol/L). Gram stain is negative. What is the most appropriate initial management?
Q55
A 46-year-old woman from Pakistan with smear-positive pulmonary tuberculosis has been on treatment with rifampicin, isoniazid, pyrazinamide, and ethambutol for 3 weeks. She attends clinic complaining of numbness and tingling in both feet. She has no other medical history and takes no other medications. On examination, she has reduced sensation to light touch and pinprick in a glove-and-stocking distribution, and absent ankle reflexes. Which medication requires adjustment and what should be added to prevent progression?
Q56
A 34-year-old man with HIV infection (CD4 count 55 cells/mm³) presents with a 4-week history of headache and fever. Lumbar puncture shows: opening pressure 32 cm H₂O, white cells 25/mm³ (90% lymphocytes), protein 0.9 g/L, glucose 2.1 mmol/L (plasma glucose 5.4 mmol/L). India ink stain is positive. He is started on intravenous liposomal amphotericin B and flucytosine. After 5 days of treatment, he develops acute deterioration with worsening headache, confusion, and reduced GCS. Repeat CT head shows no new findings. What is the most likely cause of his deterioration?
Q57
A 67-year-old woman with a history of mastoidectomy 20 years ago presents with a 2-day history of fever, severe headache, and confusion. On examination, temperature is 39.1°C, GCS 13/15, there is left-sided otorrhoea and neck stiffness. CT head shows no mass lesion or hydrocephalus. Lumbar puncture is performed: opening pressure 28 cm H₂O, white cells 2400/mm³ (88% neutrophils), protein 2.8 g/L, glucose 1.8 mmol/L (plasma glucose 6.2 mmol/L). Gram stain shows Gram-positive diplococci. What is the most appropriate initial antibiotic regimen?
Q58
A 41-year-old man from India presents with a 5-week history of productive cough, fever, and weight loss. Chest X-ray shows bilateral upper lobe infiltrates with cavitation. Three sputum samples are smear-positive for acid-fast bacilli. He is started on rifampicin, isoniazid, pyrazinamide, and ethambutol. Culture subsequently grows Mycobacterium tuberculosis with the following sensitivities: sensitive to rifampicin and isoniazid, resistant to pyrazinamide and streptomycin. What is the most appropriate treatment duration?
Q59
A 29-year-old woman presents with a 14-hour history of severe headache, fever, photophobia, and vomiting. On examination, she is drowsy with GCS 13/15, temperature 38.9°C, blood pressure 105/65 mmHg, heart rate 118 bpm. There is marked neck stiffness and a non-blanching purpuric rash on her lower limbs. Blood cultures are taken and she is given immediate empirical treatment. What is the minimum duration she should be considered infectious to close contacts requiring chemoprophylaxis?
Q60
A 52-year-old man with newly diagnosed smear-positive pulmonary tuberculosis is started on rifampicin, isoniazid, pyrazinamide, and ethambutol. After 2 weeks of treatment, he develops painful, red, swollen joints affecting both ankles and the right wrist. Blood tests show: urate 580 µmol/L (reference range 200-430), creatinine 98 µmol/L. What is the most appropriate management of this complication?
Serious & Notifiable Infections UK Medical PG Practice Questions and MCQs
Question 51: A 38-year-old homeless man with alcohol dependency is diagnosed with smear-positive pulmonary tuberculosis. He has a history of poor treatment adherence for other medical conditions. Molecular testing shows fully sensitive Mycobacterium tuberculosis. He is started on standard four-drug therapy. What is the most appropriate strategy to optimize treatment completion in this patient?
A. Arrange daily directly observed therapy (DOT) for the entire 6-month treatment course (Correct Answer)
B. Arrange daily DOT for the intensive phase only (first 2 months)
C. Provide weekly dispensing with self-administration and intensive case management
D. Arrange admission to hospital for the first 2 months to ensure adherence
E. Use monthly injectable rifampicin and isoniazid preparations
Explanation: ***Arrange daily directly observed therapy (DOT) for the entire 6-month treatment course***
- In patients with high risk factors for non-adherence, such as **homelessness**, **alcohol dependency**, and a history of poor medical compliance, **Directly Observed Therapy (DOT)** is the gold standard to ensure treatment completion.
- Supervising every dose for the **entire 6-month course** (not just the intensive phase) is crucial to prevent **treatment failure**, **relapse**, and the development of **drug resistance**.
*Arrange daily DOT for the intensive phase only (first 2 months)*
- Limiting DOT to only the **intensive phase** is insufficient for this patient, as his psychosocial risk factors persist throughout the entire treatment duration.
- The risk of **acquired drug resistance** remains high during the continuation phase if doses are missed after the first 2 months.
*Provide weekly dispensing with self-administration and intensive case management*
- **Self-administration** is high-risk in patients with severe social instability; medication can be easily lost, stolen, or forgotten due to **alcohol use disorder**.
- Case management is a useful adjunct, but it does not provide the **level of supervision** required to guarantee ingestion of anti-TB drugs in such high-risk scenarios.
*Arrange admission to hospital for the first 2 months to ensure adherence*
- Prolonged **hospitalization** solely for adherence is unnecessary and costly, as **community-based DOT** is effective and less restrictive for the patient.
- Admission does not address the need for adherence during the subsequent **4-month continuation phase** once the patient returns to his unstable environment.
*Use monthly injectable rifampicin and isoniazid preparations*
- There are no standard **monthly injectable** versions of first-line anti-TB drugs; treatment requires **daily oral dosing** to maintain therapeutic levels.
- Reliance on non-existent long-acting injectables would lead to **subtherapeutic levels** and treatment failure in an active smear-positive patient.
Question 52: A 25-year-old woman is investigated for persistent headache. She is found to have a CSF opening pressure of 28 cm H₂O. The CSF shows: white cells 8/mm³ (all lymphocytes), protein 0.65 g/L, glucose 2.9 mmol/L (plasma glucose 5.2 mmol/L). Gram stain, India ink stain, and routine bacterial culture are negative. She was born in Hong Kong and moved to the UK at age 5. She works as a teacher and is in good general health with no weight loss or fever. What investigation is most likely to establish the diagnosis?
A. CSF tuberculosis PCR (GeneXpert MTB/RIF)
B. CSF cytology for malignant cells
C. MRI brain with gadolinium contrast (Correct Answer)
D. Repeat lumbar puncture after 1 week for comparison
E. CSF adenosine deaminase (ADA) level
Explanation: ***MRI brain with gadolinium contrast***
- The patient presents with **elevated opening pressure**, mild lymphocytic pleocytosis, and elevated protein, requiring imaging to exclude **basal meningeal enhancement**, tuberculomas, or venous sinus thrombosis.
- MRI is the most sensitive imaging modality to differentiate between **idiopathic intracranial hypertension (IIH)** and subacute infections like **tuberculous meningitis** in a high-risk patient.
*CSF tuberculosis PCR (GeneXpert MTB/RIF)*
- While specific, **GeneXpert** has a relatively low sensitivity in paucibacillary CSF samples and may yield a false negative in early or mild disease.
- It is generally used as a confirmatory tool rather than the primary investigation to establish a diagnosis of intracranial pathology.
*CSF cytology for malignant cells*
- **Neoplastic meningitis** typically presents with more significant constitutional symptoms or more profound CSF abnormalities such as very low glucose.
- Cytology is not the first-line investigation when imaging and basic CSF biochemistry have not yet narrowed the differential to malignancy.
*Repeat lumbar puncture after 1 week for comparison*
- Delaying diagnosis by waiting one week is inappropriate given the risk of **permanent visual loss** from high intracranial pressure or progression of infection.
- Serial punctures are not diagnostic tools; imaging must be performed first to ensure there is no **obstructive hydrocephalus** or space-occupying lesion.
*CSF adenosine deaminase (ADA) level*
- **ADA levels** are helpful supportive markers for tuberculosis but lack the specificity to definitively establish a diagnosis on their own.
- ADA results can be elevated in other conditions like **lymphoma** or neurosarcoidosis, making MRI more useful for visualizing the distribution of disease.
Question 53: A 58-year-old man with newly diagnosed sputum smear-positive pulmonary tuberculosis is started on rifampicin 600 mg daily, isoniazid 300 mg daily, pyrazinamide 2000 mg daily, and ethambutol 1200 mg daily. His baseline investigations show: ALT 38 U/L, bilirubin 14 µmol/L, creatinine 105 µmol/L, eGFR 68 mL/min/1.73m². He weighs 95 kg. Two weeks into treatment, repeat blood tests show: ALT 165 U/L, bilirubin 18 µmol/L. He is asymptomatic. What is the most appropriate management?
A. Continue current regimen and recheck liver function in 1 week (Correct Answer)
B. Stop all drugs until liver function normalizes, then rechallenge sequentially
C. Reduce doses of rifampicin and isoniazid by 50% and monitor closely
D. Discontinue pyrazinamide and continue other three drugs
E. Continue current regimen but add ursodeoxycholic acid
Explanation: ***Continue current regimen and recheck liver function in 1 week***- Guidelines recommend continuing TB treatment in **asymptomatic** patients if the **ALT is less than 5 times** the upper limit of normal (ULN).- This patient’s ALT (165 U/L) is approximately **4.3 times the ULN** (38 U/L), and since he is asymptomatic with a **normal bilirubin**, close monitoring is the standard of care.*Stop all drugs until liver function normalizes, then rechallenge sequentially*- Discontinuation of anti-TB drugs is typically indicated if the **ALT >3 times ULN with symptoms** (e.g., nausea, jaundice) or **ALT >5 times ULN** if asymptomatic.- Stopping treatment prematurely increases the risk of **drug resistance** and delays the clearance of **Mycobacterium tuberculosis** infection, which is crucial for public health.*Reduce doses of rifampicin and isoniazid by 50% and monitor closely*- **Sub-therapeutic dosing** is not recommended as it promotes the development of **multidrug-resistant TB (MDR-TB)**, compromising treatment efficacy.- Management of suspected drug-induced hepatotoxicity requires either maintaining the full dose with monitoring (as in this case) or **complete cessation** followed by a structured rechallenge.*Discontinue pyrazinamide and continue other three drugs*- Although **pyrazinamide** is known for its higher potential for hepatotoxicity, the regimen should not be modified unless the criteria for **drug-induced liver injury (DILI)** are strictly met.- Prematurely modifying the regimen without meeting established threshold criteria may compromise the **intensive phase** of treatment and lead to suboptimal clinical outcomes.*Continue current regimen but add ursodeoxycholic acid*- **Ursodeoxycholic acid** has no proven clinical role in preventing or treating **anti-tuberculosis drug-induced hepatotoxicity** and is not a standard adjunct in this setting.- The primary management strategy for raised transaminases, when not requiring cessation, is **biochemical monitoring** and careful clinical assessment for symptoms of hepatitis.
Question 54: A 12-year-old boy presents to the emergency department with an 8-hour history of fever, severe headache, and vomiting. On examination, temperature is 38.7°C, heart rate 125 bpm, blood pressure 95/60 mmHg, GCS 14/15. There is neck stiffness but no rash. A senior clinician performs lumbar puncture which shows: clear CSF, white cells 180/mm³ (65% lymphocytes, 35% neutrophils), protein 0.8 g/L, glucose 3.2 mmol/L (plasma glucose 5.8 mmol/L). Gram stain is negative. What is the most appropriate initial management?
A. Start intravenous ceftriaxone and admit for observation
B. Start intravenous aciclovir and supportive care
C. Discharge with safety-netting advice as viral meningitis is most likely
D. Start intravenous ceftriaxone and aciclovir pending further investigation (Correct Answer)
E. Repeat lumbar puncture in 12 hours to clarify diagnosis
Explanation: ***Start intravenous ceftriaxone and aciclovir pending further investigation***- The patient presents with **meningism** and an ambiguous CSF profile showing **lymphocytic pleocytosis**, making it difficult to definitively distinguish between bacterial and viral causes.- Empiric treatment with **ceftriaxone** (for bacterial meningitis) and **aciclovir** (for HSV encephalitis) is mandatory in an unwell patient with **GCS 14** until cultures and PCR results are available.*Start intravenous ceftriaxone and admit for observation*- While ceftriaxone covers common bacterial pathogens, it fails to address potential **HSV encephalitis**, which can also present with headache and slightly altered consciousness.- The CSF findings of **lymphocytic predominance** and **mildly elevated protein** are consistent with viral etiologies that require specific antiviral therapy.*Start intravenous aciclovir and supportive care*- This approach is dangerously narrow because it ignores the risk of **bacterial meningitis**, which can occasionally present with atypical CSF counts early in the disease course.- Failing to provide **empiric antibiotics** like ceftriaxone in a patient with fever and neck stiffness increases the risk of rapid neurological deterioration.*Discharge with safety-netting advice as viral meningitis is most likely*- Discharging an acutely unwell child with **altered GCS** and signs of systemic infection is clinically unsafe and violates standard management protocols.- Even if viral etiology is suspected, the patient requires **inpatient management** and monitoring to ensure clinical stability and rule out life-threatening alternatives.*Repeat lumbar puncture in 12 hours to clarify diagnosis*- Delaying treatment to repeat a procedure is inappropriate when the patient is already showing signs of **tachycardia and hypotension** (incipient shock).- Starting **life-saving therapy** takes absolute priority over obtaining perfectly clear diagnostic results in the setting of suspected meningitis.
Question 55: A 46-year-old woman from Pakistan with smear-positive pulmonary tuberculosis has been on treatment with rifampicin, isoniazid, pyrazinamide, and ethambutol for 3 weeks. She attends clinic complaining of numbness and tingling in both feet. She has no other medical history and takes no other medications. On examination, she has reduced sensation to light touch and pinprick in a glove-and-stocking distribution, and absent ankle reflexes. Which medication requires adjustment and what should be added to prevent progression?
A. Discontinue ethambutol and replace with levofloxacin
B. Reduce dose of isoniazid and add pyridoxine 10 mg daily
C. Reduce dose of ethambutol and add thiamine 100 mg daily
D. Continue same dose of all drugs and add pyridoxine 50 mg daily (Correct Answer)
E. Discontinue isoniazid and replace with levofloxacin
Explanation: ***Continue same dose of all drugs and add pyridoxine 50 mg daily***- The patient is experiencing **isoniazid-induced peripheral neuropathy**, which occurs because isoniazid increases the excretion of and interferes with the metabolism of **Vitamin B6 (pyridoxine)**.- For established neuropathy, the treatment is to add high-dose **pyridoxine (50–100 mg daily)** while maintaining the standard **isoniazid** dose to avoid compromising the efficacy of the tuberculosis regimen.*Reduce dose of isoniazid and add pyridoxine 10 mg daily*- Reducing the dose of **isoniazid** is not recommended as it is a primary bactericidal agent essential for successful tuberculosis treatment.- **Pyridoxine 10 mg** is a prophylactic dose used to prevent deficiency, but a higher therapeutic dose (at least 50 mg) is required once neuropathy symptoms have manifested.*Reduce dose of ethambutol and add thiamine 100 mg daily*- **Ethambutol** is primarily associated with **optic neuritis** (loss of visual acuity and red-green color blindness) rather than peripheral sensory neuropathy.- **Thiamine (Vitamin B1)** is used to treat Wernicke-Korsakoff syndrome and certain types of Beriberi, but it does not address the specific metabolic interference caused by isoniazid.*Discontinue ethambutol and replace with levofloxacin*- **Ethambutol** is not the causative agent for the patient's sensory numbness and absent ankle reflexes, so discontinuing it would not resolve the symptoms.- Replacing a first-line drug with **levofloxacin** is reserved for drug-resistant cases or severe drug toxicity and is not indicated for manageable side effects like neuropathy.*Discontinue isoniazid and replace with levofloxacin*- **Isoniazid** is a cornerstone of TB treatment, and discontinuation is unnecessary if the side effect can be managed with **pyridoxine supplementation**.- Replacing it with **levofloxacin** increases the risk of treatment failure and the development of drug resistance in a patient with a previously sensitive smear-positive infection.
Question 56: A 34-year-old man with HIV infection (CD4 count 55 cells/mm³) presents with a 4-week history of headache and fever. Lumbar puncture shows: opening pressure 32 cm H₂O, white cells 25/mm³ (90% lymphocytes), protein 0.9 g/L, glucose 2.1 mmol/L (plasma glucose 5.4 mmol/L). India ink stain is positive. He is started on intravenous liposomal amphotericin B and flucytosine. After 5 days of treatment, he develops acute deterioration with worsening headache, confusion, and reduced GCS. Repeat CT head shows no new findings. What is the most likely cause of his deterioration?
A. Amphotericin B-induced nephrotoxicity with uraemic encephalopathy
B. Inadequate antifungal penetration to CSF requiring intrathecal therapy
C. Paradoxical inflammatory deterioration due to immune reconstitution
D. Raised intracranial pressure requiring therapeutic lumbar puncture (Correct Answer)
E. Treatment failure requiring addition of voriconazole
Explanation: ***Raised intracranial pressure requiring therapeutic lumbar puncture***
- The patient has **cryptococcal meningitis** with an already elevated **opening pressure (32 cm H₂O)**; acute deterioration suggests it has worsened due to poor CSF resorption from **fungal capsular polysaccharides**.
- Management of symptomatic raised ICP in these patients requires repeat **therapeutic lumbar punctures** to lower pressure by 50% or to <20 cm H₂O.
*Amphotericin B-induced nephrotoxicity with uraemic encephalopathy*
- While **Amphotericin B** is nephrotoxic, it typically causes **electrolyte disturbances** and gradual creatinine rise rather than acute coma without preceding systemic signs.
- **Liposomal** formulations are specifically designed to reduce renal toxicity compared to conventional amphotericin.
*Inadequate antifungal penetration to CSF requiring intrathecal therapy*
- The combination of **amphotericin B and flucytosine** is the gold standard induction therapy and achieves very high levels in the **CNS**.
- **Intrathecal therapy** is generally contraindicated and not a standard of care for cryptococcal meningitis due to risks of chemical arachnoiditis.
*Paradoxical inflammatory deterioration due to immune reconstitution*
- **Immune Reconstitution Inflammatory Syndrome (IRIS)** typically occurs after the initiation of **antiretroviral therapy (ART)**, which this patient has not yet started.
- Clinical guidelines recommend delaying ART by 4-6 weeks to prevent life-threatening **cerebral edema** associated with paradoxical inflammation.
*Treatment failure requiring addition of voriconazole*
- **Voriconazole** is not indicated as a first-line agent or as an add-on during the initial 5 days of standard induction therapy.
- Clinical deterioration at this stage is more often due to **mechanical complications** (ICP) rather than primary resistance to amphotericin.
Question 57: A 67-year-old woman with a history of mastoidectomy 20 years ago presents with a 2-day history of fever, severe headache, and confusion. On examination, temperature is 39.1°C, GCS 13/15, there is left-sided otorrhoea and neck stiffness. CT head shows no mass lesion or hydrocephalus. Lumbar puncture is performed: opening pressure 28 cm H₂O, white cells 2400/mm³ (88% neutrophils), protein 2.8 g/L, glucose 1.8 mmol/L (plasma glucose 6.2 mmol/L). Gram stain shows Gram-positive diplococci. What is the most appropriate initial antibiotic regimen?
A. Intravenous ceftriaxone
B. Intravenous ceftriaxone and vancomycin
C. Intravenous ceftriaxone, vancomycin, and amoxicillin
D. Intravenous ceftriaxone, vancomycin, and metronidazole (Correct Answer)
E. Intravenous meropenem and vancomycin
Explanation: ***Intravenous ceftriaxone, vancomycin, and metronidazole***
- The patient presents with **bacterial meningitis** secondary to **chronic otitis media** and a history of **mastoid surgery**, necessitating empirical coverage for **anaerobes** via **metronidazole**.
- **Ceftriaxone** and **vancomycin** are essential for suspected **Streptococcus pneumoniae** (indicated by **Gram-positive diplococci**) and to address potential **penicillin resistance**.
*Intravenous ceftriaxone*
- This monotherapy is insufficient as it does not reliably cover **penicillin-resistant pneumococci**, which are a significant concern in bacterial meningitis, especially in an older patient.
- It also completely lacks coverage for **anaerobic organisms**, which are highly probable given the **otogenic source** (otorrhoea, mastoidectomy history).
*Intravenous ceftriaxone and vancomycin*
- This is the standard empirical regimen for **community-acquired bacterial meningitis** to cover *S. pneumoniae* and *N. meningitidis*, including resistant strains.
- However, it **lacks anaerobic coverage**, which is crucial given the clear evidence of an **otogenic source** (otorrhoea, history of mastoidectomy).
*Intravenous ceftriaxone, vancomycin, and amoxicillin*
- **Amoxicillin** is typically added for patients over 50 years to cover **Listeria monocytogenes**, but the Gram stain revealed **Gram-positive diplococci**, not the Gram-positive bacilli characteristic of Listeria.
- This regimen still fails to provide adequate **anaerobic coverage** for a suspected **otogenic infection**, which is a critical omission in this case.
*Intravenous meropenem and vancomycin*
- While **meropenem** is a broad-spectrum carbapenem that covers Gram-positives, Gram-negatives, and anaerobes, the combination of **ceftriaxone, vancomycin, and metronidazole** is the more targeted and usually preferred empirical regimen for **otogenic meningitis**.
- Using **carbapenems** as first-line therapy, when a more specific regimen is effective, can contribute to resistance and is often reserved for specific highly resistant pathogens or immunocompromised patients.
Question 58: A 41-year-old man from India presents with a 5-week history of productive cough, fever, and weight loss. Chest X-ray shows bilateral upper lobe infiltrates with cavitation. Three sputum samples are smear-positive for acid-fast bacilli. He is started on rifampicin, isoniazid, pyrazinamide, and ethambutol. Culture subsequently grows Mycobacterium tuberculosis with the following sensitivities: sensitive to rifampicin and isoniazid, resistant to pyrazinamide and streptomycin. What is the most appropriate treatment duration?
A. Continue all four drugs for 2 months, then rifampicin and isoniazid for 4 months (total 6 months)
B. Continue rifampicin, isoniazid, and ethambutol for 2 months, then rifampicin and isoniazid for 7 months (total 9 months)
C. Continue rifampicin, isoniazid, and ethambutol for 2 months, then rifampicin and isoniazid for 4 months (total 6 months) (Correct Answer)
D. Continue rifampicin, isoniazid, and ethambutol for 3 months, then rifampicin and isoniazid for 9 months (total 12 months)
E. Refer to specialist MDR-TB service for second-line drug regimen
Explanation: ***Continue rifampicin, isoniazid, and ethambutol for 2 months, then rifampicin and isoniazid for 4 months (total 6 months)***- Isolated **pyrazinamide resistance** (and streptomycin resistance) with **sensitivity to rifampicin and isoniazid** allows for a standard 6-month treatment duration for pulmonary TB.- The intensive phase becomes 2 months of R-H-E (omitting Z), and the continuation phase remains 4 months of R-H, which is sufficient to achieve a **sterilizing effect** as the core drugs are fully active.*Continue all four drugs for 2 months, then rifampicin and isoniazid for 4 months (total 6 months)*- Continuing **pyrazinamide** after resistance is confirmed is inappropriate as it adds unnecessary **hepatotoxicity risk** and other adverse effects without therapeutic benefit.- Successful treatment requires the regimen to be modified based on **drug susceptibility testing (DST)** to include only effective drugs.*Continue rifampicin, isoniazid, and ethambutol for 2 months, then rifampicin and isoniazid for 7 months (total 9 months)*- Extending the continuation phase to 7 months (total 9 months) is typically reserved for specific situations like **cavitary disease** with positive sputum cultures at 2 months of treatment, or certain forms of extrapulmonary TB.- While the patient has cavitary disease, isolated **PZA resistance** alone does not automatically necessitate a 9-month regimen if the patient is sensitive to rifampicin and isoniazid and is responding to therapy.*Continue rifampicin, isoniazid, and ethambutol for 3 months, then rifampicin and isoniazid for 9 months (total 12 months)*- A 12-month regimen is unnecessarily long for standard **pulmonary TB**, even with PZA resistance, and is usually reserved for complex forms like **TB meningitis** or extensive bone and joint TB.- Such extended treatment increases the risk of **drug toxicity** and decreases **patient adherence** without additional efficacy in this scenario.*Refer to specialist MDR-TB service for second-line drug regimen*- **Multidrug-resistant TB (MDR-TB)** is defined as resistance to at least both **rifampicin and isoniazid**.- Since this patient's isolate is sensitive to both rifampicin and isoniazid, it does not meet the criteria for MDR-TB, and therefore, a referral for second-line, typically more toxic, drugs is not indicated.
Question 59: A 29-year-old woman presents with a 14-hour history of severe headache, fever, photophobia, and vomiting. On examination, she is drowsy with GCS 13/15, temperature 38.9°C, blood pressure 105/65 mmHg, heart rate 118 bpm. There is marked neck stiffness and a non-blanching purpuric rash on her lower limbs. Blood cultures are taken and she is given immediate empirical treatment. What is the minimum duration she should be considered infectious to close contacts requiring chemoprophylaxis?
A. Until 12 hours of appropriate antibiotic therapy
B. Until 24 hours of appropriate antibiotic therapy (Correct Answer)
C. Until 48 hours of appropriate antibiotic therapy
D. Until 72 hours of appropriate antibiotic therapy
E. Until completion of the full antibiotic course
Explanation: ***Until 24 hours of appropriate antibiotic therapy***- For cases of **meningococcal meningitis**, as suggested by the clinical presentation including the **non-blanching purpuric rash**, patients are considered infectious until they have received **24 hours** of effective systemic antibiotics.- This duration is critical as it ensures sufficient eradication of **Neisseria meningitidis** from the nasopharynx, significantly reducing the risk of transmission to close contacts, as per public health guidelines.*Until 12 hours of appropriate antibiotic therapy*- This timeframe is generally considered insufficient to reliably eliminate **Neisseria meningitidis** from the nasopharynx to a safe level, meaning the patient could still be contagious.- Relying on 12 hours would prematurely lift precautions and could potentially expose close contacts to the pathogen, negating the purpose of **chemoprophylaxis**.*Until 48 hours of appropriate antibiotic therapy*- While the patient continues treatment, they are typically no longer considered infectious to contacts well before the **48-hour** mark if effective antibiotics, such as **third-generation cephalosporins**, are being administered.- Extending infectious precautions to 48 hours would be an unnecessary prolongation beyond the evidence-based window for **meningococcal transmission**.*Until 72 hours of appropriate antibiotic therapy*- A 72-hour period is excessively long for defining the cessation of infectiousness in **meningococcal disease**, given the prompt response of the bacteria to appropriate antibiotic therapy.- This duration is usually more relevant for monitoring **clinical improvement** or awaiting full culture sensitivities, rather than determining the immediate **risk of transmission**.*Until completion of the full antibiotic course*- Patients become non-infectious much earlier in the course of treatment, as the goal for reducing transmission is the eradication of bacteria from the **respiratory tract**, not the complete resolution of the clinical infection.- Requiring isolation or precautions for the entire antibiotic course would be impractical and not supported by guidelines for **contact management** and **chemoprophylaxis**.
Question 60: A 52-year-old man with newly diagnosed smear-positive pulmonary tuberculosis is started on rifampicin, isoniazid, pyrazinamide, and ethambutol. After 2 weeks of treatment, he develops painful, red, swollen joints affecting both ankles and the right wrist. Blood tests show: urate 580 µmol/L (reference range 200-430), creatinine 98 µmol/L. What is the most appropriate management of this complication?
A. Discontinue ethambutol and replace with levofloxacin
B. Discontinue pyrazinamide and continue with three-drug therapy (Correct Answer)
C. Add allopurinol and continue all four anti-tuberculosis drugs
D. Stop all anti-tuberculosis drugs and rechallenge sequentially
E. Add colchicine and continue all four anti-tuberculosis drugs
Explanation: ***Discontinue pyrazinamide and continue with three-drug therapy***- **Pyrazinamide** is well-known for inhibiting the renal secretion of **urates**, leading to **hyperuricemia** and potentially precipitating **acute gouty arthritis**.- When clinically significant gout occurs (painful, red, swollen joints), the standard management is to **discontinue pyrazinamide** and continue the intensive phase with the remaining three drugs, typically for an extended duration.*Discontinue ethambutol and replace with levofloxacin*- **Ethambutol** is primarily associated with **optic neuritis** (visual acuity and color vision loss), not hyperuricemia or joint pain.- Replacing it with a fluoroquinolone is unnecessary here because ethambutol is not the cause of the patient's **acute arthralgia**.*Add allopurinol and continue all four anti-tuberculosis drugs*- Adding **allopurinol** is generally ineffective because pyrazinamide-induced hyperuricemia is resistant to standard urate-lowering therapy due to **competitive inhibition** in the renal tubules.- It is clinically preferable to remove the offending agent rather than adding long-term medications to manage a **drug-induced side effect**.*Stop all anti-tuberculosis drugs and rechallenge sequentially*- Sequential **rechallenge** is reserved for severe **hypersensitivity reactions** (like DRESS or Stevens-Johnson) or severe **hepatotoxicity** where the causative agent is unclear.- In this case, the **biochemical evidence** (elevated urate) clearly identifies pyrazinamide as the culprit, making a full stop and rechallenge unnecessary.*Add colchicine and continue all four anti-tuberculosis drugs*- While **colchicine** or NSAIDs may provide temporary symptomatic relief for the pain, they do not address the underlying **metabolic disturbance** caused by the pyrazinamide.- Continuing the offending drug despite **clinical gout** increases the risk of recurrent attacks and potential **urate nephropathy**.
