A 43-year-old woman with rheumatoid arthritis is about to commence tocilizumab (IL-6 inhibitor) therapy. Screening investigations show: interferon-gamma release assay (IGRA) positive, chest X-ray normal, no symptoms of active tuberculosis. She has no history of previous tuberculosis treatment. What is the most appropriate management regarding tuberculosis before starting immunosuppressive therapy?
Q92
A 31-year-old man presents with a 7-week history of headache, fever, and personality change. He is a recent immigrant from India. On examination, GCS is 13/15, temperature 38.2°C, and he has bilateral cranial nerve VI palsies. MRI brain shows basal meningeal enhancement and multiple tuberculomas. Lumbar puncture: opening pressure 28 cmH₂O, WBC 280/mm³ (85% lymphocytes), protein 3.2 g/L, glucose 1.4 mmol/L (plasma glucose 5.6 mmol/L). GeneXpert MTB/RIF on CSF is positive for M. tuberculosis with rifampicin sensitivity. He is started on rifampicin, isoniazid, pyrazinamide, and ethambutol with adjunctive dexamethasone. What is the most important additional immediate management to prevent permanent neurological sequelae?
Q93
Which one of the following adverse effects associated with anti-tuberculosis medications requires immediate and permanent discontinuation of the causative drug?
Q94
A 52-year-old man presents with a 4-week history of headache and confusion. He has HIV infection with a CD4 count of 45 cells/mm³ and is not currently on antiretroviral therapy. CT head shows multiple ring-enhancing lesions. Lumbar puncture shows: WBC 12/mm³ (80% lymphocytes), protein 0.8 g/L, glucose 3.2 mmol/L (plasma glucose 5.8 mmol/L). Toxoplasma serology is IgG positive. He is started on sulfadiazine and pyrimethamine. After 10 days of treatment there is no clinical improvement and repeat CT shows progression of lesions. What is the most appropriate next step in management?
Q95
A 5-year-old girl presents with a 6-hour history of fever, headache, and drowsiness. On examination, she has GCS 12/15, temperature 39.5°C, and a petechial rash on her trunk. Blood cultures are taken and intravenous ceftriaxone 80 mg/kg is commenced. Lumbar puncture shows turbid CSF with opening pressure 24 cmH₂O. Which prophylactic measure for household contacts is most appropriate?
Q96
A 38-year-old healthcare worker has recently completed BCG vaccination after a negative tuberculin skin test. She now works in a respiratory ward with frequent exposure to patients with tuberculosis. Six months later, she develops a persistent cough. Chest X-ray shows right upper lobe consolidation. What is the most appropriate initial diagnostic approach?
Q97
A 65-year-old woman with type 2 diabetes presents with confusion, fever, and left-sided focal seizures. CT head shows a right temporal lobe lesion with surrounding oedema. Lumbar puncture shows: WBC 520/mm³ (70% lymphocytes), protein 0.9 g/L, glucose 3.8 mmol/L (plasma glucose 8.2 mmol/L), and red blood cells 850/mm³. PCR is positive for herpes simplex virus type 1. She is started on intravenous aciclovir. What additional immediate treatment is most likely to improve neurological outcome?
Q98
A 27-year-old man from Nigeria presents with a 10-week history of progressive headache, vomiting, and personality change. He has been in the UK for 8 months. On examination, he is confused with GCS 13/15, temperature 37.8°C, and bilateral papilloedema. CT head shows hydrocephalus with basal enhancement. Lumbar puncture after normal coagulation: opening pressure 32 cmH₂O, WBC 180/mm³ (90% lymphocytes), protein 2.2 g/L, glucose 1.8 mmol/L (plasma glucose 5.4 mmol/L). India ink stain is positive. What is the most important initial investigation to guide treatment duration and prognosis?
Q99
A 32-year-old man presents to the emergency department with a 12-hour history of severe headache, fever of 39.2°C, and two episodes of vomiting. He has photophobia and neck stiffness. He had a splenectomy 5 years ago following a road traffic accident. Blood cultures are taken. What is the most appropriate immediate antibiotic regimen before lumbar puncture results are available?
Q100
A 48-year-old woman with smear-positive pulmonary tuberculosis has been on rifampicin, isoniazid, pyrazinamide, and ethambutol for 6 weeks. She now complains of reduced visual acuity and difficulty distinguishing red and green colours. Visual acuity testing shows deterioration from 6/6 to 6/18 bilaterally. What is the most likely cause and appropriate action?
Serious & Notifiable Infections UK Medical PG Practice Questions and MCQs
Question 91: A 43-year-old woman with rheumatoid arthritis is about to commence tocilizumab (IL-6 inhibitor) therapy. Screening investigations show: interferon-gamma release assay (IGRA) positive, chest X-ray normal, no symptoms of active tuberculosis. She has no history of previous tuberculosis treatment. What is the most appropriate management regarding tuberculosis before starting immunosuppressive therapy?
A. Start tocilizumab immediately as chest X-ray is normal and there are no symptoms
B. Commence isoniazid 300 mg daily for 6 months before starting tocilizumab
C. Commence rifampicin and isoniazid for 3 months before starting tocilizumab (Correct Answer)
D. Perform CT thorax and bronchoscopy to exclude active disease before any treatment decisions
E. Commence full four-drug anti-tuberculosis therapy (rifampicin, isoniazid, pyrazinamide, ethambutol) for 2 months before starting tocilizumab
Explanation: ***Commence rifampicin and isoniazid for 3 months before starting tocilizumab***
- This patient has **latent tuberculosis infection (LTBI)**, as indicated by a **positive IGRA** and normal chest X-ray; treatment is mandatory before starting **IL-6 inhibitors** like tocilizumab to prevent reactivation.
- The **3-month Rifampicin and Isoniazid (3RH)** regimen is a preferred LTBI strategy due to higher completion rates and similar efficacy compared to longer monotherapy courses.
*Start tocilizumab immediately as chest X-ray is normal and there are no symptoms*
- Proceeding without treating LTBI carries a high risk of **active TB reactivation** once biologic immunosuppression is introduced.
- Guidelines mandate that prophylaxis should ideally be initiated for at least **one month** (some experts suggest completion) prior to starting biologics.
*Commence isoniazid 300 mg daily for 6 months before starting tocilizumab*
- While **monotherapy with Isoniazid** for 6 months is an acceptable alternative for LTBI, it is generally less preferred than the shorter 3-month combined regimen.
- This option is less optimal in this context compared to the **shorter, more effective duration** provided by the combination of Rifampicin and Isoniazid.
*Perform CT thorax and bronchoscopy to exclude active disease before any treatment decisions*
- Invasive procedures and advanced imaging are **not indicated** if the patient is asymptomatic and the standard screening **chest X-ray** is normal.
- These investigations are reserved for cases with **suspicious radiographic findings** or clinical symptoms of pulmonary tuberculosis.
*Commence full four-drug anti-tuberculosis therapy (rifampicin, isoniazid, pyrazinamide, ethambutol) for 2 months before starting tocilizumab*
- **Four-drug therapy (RIPE)** is the intensive phase treatment for **active tuberculosis**, not the prophylaxis required for latent infection.
- Using this regimen for LTBI results in **unnecessary toxicity** and does not follow established screening and preventative protocols.
Question 92: A 31-year-old man presents with a 7-week history of headache, fever, and personality change. He is a recent immigrant from India. On examination, GCS is 13/15, temperature 38.2°C, and he has bilateral cranial nerve VI palsies. MRI brain shows basal meningeal enhancement and multiple tuberculomas. Lumbar puncture: opening pressure 28 cmH₂O, WBC 280/mm³ (85% lymphocytes), protein 3.2 g/L, glucose 1.4 mmol/L (plasma glucose 5.6 mmol/L). GeneXpert MTB/RIF on CSF is positive for M. tuberculosis with rifampicin sensitivity. He is started on rifampicin, isoniazid, pyrazinamide, and ethambutol with adjunctive dexamethasone. What is the most important additional immediate management to prevent permanent neurological sequelae?
A. Serial lumbar punctures to reduce intracranial pressure
B. Urgent neurosurgical consultation for ventriculoperitoneal shunt insertion (Correct Answer)
C. Increase dexamethasone dose to 16 mg daily for more potent anti-inflammatory effect
D. Add moxifloxacin as a fifth drug to improve CSF penetration
E. Immediate loading with intravenous phenytoin for seizure prophylaxis
Explanation: ***Urgent neurosurgical consultation for ventriculoperitoneal shunt insertion***- This patient exhibits signs of **obstructive hydrocephalus**, including raised intracranial pressure (28 cmH₂O), **GCS 13/15**, and **bilateral VI nerve palsies**.- Urgent neurosurgical intervention is vital to prevent **permanent neurological sequelae** or death caused by the basal exudates characteristic of **tuberculous meningitis**.*Serial lumbar punctures to reduce intracranial pressure*- While serial lumbar punctures may temporarily alleviate pressure in **communicating hydrocephalus**, they are insufficient for the definitive management of **obstructive hydrocephalus**.- This approach is more commonly used in **cryptococcal meningitis** rather than as a primary surgical solution for TB-related CSF obstruction.*Increase dexamethasone dose to 16 mg daily for more potent anti-inflammatory effect*- The patient is already on **adjunctive dexamethasone**, which is the gold standard to reduce meningeal inflammation and mortality in **TB meningitis**.- Increasing the dose beyond standard protocols (usually 0.4mg/kg/day tapering over 6-8 weeks) does not replace the need for **surgical decompression** of hydrocephalus.*Add moxifloxacin as a fifth drug to improve CSF penetration*- Since the GeneXpert confirmed **rifampicin sensitivity**, the standard intensive phase (RHZE) is appropriate and adequate.- Adding a **fluoroquinolone** like moxifloxacin is generally reserved for **drug-resistant tuberculosis** and does not address the mechanical issue of raised intracranial pressure.*Immediate loading with intravenous phenytoin for seizure prophylaxis*- **Prophylactic anti-epileptic drugs** are not routinely recommended in the management of TB meningitis unless the patient experiences active seizures.- This intervention does not address the primary threat to this patient's neurological status, which is **hydrocephalus** and basal meningeal enhancement.
Question 93: Which one of the following adverse effects associated with anti-tuberculosis medications requires immediate and permanent discontinuation of the causative drug?
A. Asymptomatic hyperuricaemia with serum uric acid 520 μmol/L in a patient taking pyrazinamide
B. Transient elevation of ALT to 2.5 times the upper limit of normal without symptoms in a patient taking rifampicin
C. Orange discolouration of urine and contact lenses in a patient taking rifampicin
D. Thrombocytopenia with platelet count of 45 × 10⁹/L in a patient taking rifampicin (Correct Answer)
E. Mild peripheral neuropathy with normal vitamin B6 levels in a patient taking isoniazid
Explanation: ***Thrombocytopenia with platelet count of 45 × 10⁹/L in a patient taking rifampicin***
- **Rifampicin-induced thrombocytopenia** is an immune-mediated reaction that is life-threatening and requires **immediate and permanent discontinuation**.
- Re-exposure to the drug can cause a severe, rapid drop in platelet count and **fatal hemorrhage**, making it a strict contraindication for future use.
*Asymptomatic hyperuricaemia with serum uric acid 520 μmol/L in a patient taking pyrazinamide*
- **Pyrazinamide** commonly inhibits the excretion of uric acid, but **asymptomatic hyperuricaemia** does not necessitate stopping the drug.
- Treatment is only discontinued if the patient develops clinical symptoms of **acute gouty arthritis**.
*Transient elevation of ALT to 2.5 times the upper limit of normal without symptoms in a patient taking rifampicin*
- Most guidelines recommend stopping treatment only if **ALT exceeds 5 times** the upper limit of normal (ULN) if asymptomatic, or **3 times ULN** if symptoms are present.
- Minor, **asymptomatic elevations** in liver enzymes are common during the initial phase of therapy and often resolve without intervention.
*Orange discolouration of urine and contact lenses in a patient taking rifampicin*
- This is a **harmless, expected side effect** of rifampicin due to its metabolic properties and is not a sign of toxicity.
- Patients should be counseled that it can permanently stain **soft contact lenses**, but it never requires discontinuation of therapy.
*Mild peripheral neuropathy with normal vitamin B6 levels in a patient taking isoniazid*
- **Peripheral neuropathy** is a known side effect of **Isoniazid** due to interference with pyridoxine metabolism, but it is often reversible.
- It is primarily managed by adding or increasing **Pyridoxine (Vitamin B6)** supplementation rather than permanently stopping the life-saving medication.
Question 94: A 52-year-old man presents with a 4-week history of headache and confusion. He has HIV infection with a CD4 count of 45 cells/mm³ and is not currently on antiretroviral therapy. CT head shows multiple ring-enhancing lesions. Lumbar puncture shows: WBC 12/mm³ (80% lymphocytes), protein 0.8 g/L, glucose 3.2 mmol/L (plasma glucose 5.8 mmol/L). Toxoplasma serology is IgG positive. He is started on sulfadiazine and pyrimethamine. After 10 days of treatment there is no clinical improvement and repeat CT shows progression of lesions. What is the most appropriate next step in management?
A. Add corticosteroids to reduce cerebral oedema
B. Switch to alternative anti-toxoplasma therapy with clindamycin
C. Arrange stereotactic brain biopsy for tissue diagnosis (Correct Answer)
D. Start empirical anti-tuberculosis therapy for CNS tuberculosis
E. Commence high-dose intravenous aciclovir for viral encephalitis
Explanation: ***Arrange stereotactic brain biopsy for tissue diagnosis***
- In HIV patients with a **CD4 count <100 cells/mm³** and **multiple ring-enhancing lesions**, failure to respond to empirical **sulfadiazine and pyrimethamine** after 10-14 days necessitates a biopsy.
- This step is crucial to rule out **Primary CNS Lymphoma (PCNSL)**, which frequently mimics toxoplasmosis radiologically and requires a definitive tissue diagnosis for appropriate management.
*Add corticosteroids to reduce cerebral oedema*
- Corticosteroids can cause a temporary, often significant, **regression of CNS lymphoma** lesions, which may be referred to as the 'vanishing tumor' effect, thereby confounding subsequent diagnostic efforts via biopsy.
- While they might alleviate **cerebral edema** and mass effect, they do not address the underlying pathology and could delay or obscure the definitive diagnosis.
*Switch to alternative anti-toxoplasma therapy with clindamycin*
- The patient showed **no clinical or radiological improvement** on first-line, highly effective anti-toxoplasma therapy (sulfadiazine and pyrimethamine), making it unlikely that the condition is toxoplasmosis.
- Switching to an alternative such as clindamycin would delay the critical diagnostic workup needed to identify other life-threatening conditions like **PCNSL**.
*Start empirical anti-tuberculosis therapy for CNS tuberculosis*
- **CNS Tuberculosis** typically presents with meningeal inflammation (basal meningitis) or solitary tuberculomas, rather than multiple ring-enhancing lesions with this specific clinical course and failure of toxo treatment.
- Empirical **anti-tuberculosis therapy** without a tissue diagnosis in this context is not the most appropriate step before excluding other primary differential diagnoses like PCNSL via biopsy.
*Commence high-dose intravenous aciclovir for viral encephalitis*
- **Viral encephalitis**, particularly HSV, typically causes **temporal lobe** involvement and presents with acute focal neurological deficits, seizures, or diffuse encephalopathy, rather than multiple discrete ring-enhancing lesions.
- The imaging findings and the chronic nature of symptoms are less consistent with the presentation of acute **viral encephalitis** requiring aciclovir.
Question 95: A 5-year-old girl presents with a 6-hour history of fever, headache, and drowsiness. On examination, she has GCS 12/15, temperature 39.5°C, and a petechial rash on her trunk. Blood cultures are taken and intravenous ceftriaxone 80 mg/kg is commenced. Lumbar puncture shows turbid CSF with opening pressure 24 cmH₂O. Which prophylactic measure for household contacts is most appropriate?
A. Ciprofloxacin 500 mg single dose for all household contacts (Correct Answer)
B. Rifampicin 600 mg twice daily for 2 days for all household contacts
C. Meningococcal ACWY vaccine for all household contacts within 24 hours
D. Benzylpenicillin 1.2 g intramuscularly single dose for all household contacts
E. No chemoprophylaxis required as index patient has received intravenous antibiotics
Explanation: ***Ciprofloxacin 500 mg single dose for all household contacts***
- **Ciprofloxacin** is now the preferred agent for **meningococcal chemoprophylaxis** in the UK as a single dose is highly effective at eradicating **nasopharyngeal carriage**.
- It is favored over other options due to better compliance, fewer **drug interactions**, and safety profile in various populations.
*Rifampicin 600 mg twice daily for 2 days for all household contacts*
- While effective, **rifampicin** is now considered a second-line alternative due to the requirement for **multiple doses** and potential for significant **drug interactions** via enzyme induction.
- It also has the inconvenience of potentially staining bodily fluids like urine or tears orange, which decreases patient compliance.
*Meningococcal ACWY vaccine for all household contacts within 24 hours*
- Vaccination is used as an **adjunct** to chemoprophylaxis to prevent late-onset secondary cases, but it does not provide the **immediate protection** required for acute exposure.
- Chemoprophylaxis remains the primary intervention to rapidly eliminate the **bacterial reservoir** in close contacts.
*Benzylpenicillin 1.2 g intramuscularly single dose for all household contacts*
- **Benzylpenicillin** is effective for treating invasive disease but does not reliably eradicate **nasopharyngeal carriage** of Neisseria meningitidis.
- It is not recommended for **prophylaxis** because it fails to prevent the spread of the pathogen from asymptomatic carriers to others.
*No chemoprophylaxis required as index patient has received intravenous antibiotics*
- Even though the index patient is being treated, **household contacts** remain at a significantly higher risk of developing the disease from the same source or from carriage.
- Chemoprophylaxis must be administered to all **close contacts** regardless of the patient's treatment status to break the chain of transmission.
Question 96: A 38-year-old healthcare worker has recently completed BCG vaccination after a negative tuberculin skin test. She now works in a respiratory ward with frequent exposure to patients with tuberculosis. Six months later, she develops a persistent cough. Chest X-ray shows right upper lobe consolidation. What is the most appropriate initial diagnostic approach?
A. Perform interferon-gamma release assay (IGRA) test
B. Perform Mantoux test with 2 TU tuberculin
C. Obtain three sputum samples for acid-fast bacilli smear and culture (Correct Answer)
D. Arrange high-resolution CT chest to assess for tuberculosis
E. Start empirical four-drug anti-tuberculosis therapy pending investigations
Explanation: ***Obtain three sputum samples for acid-fast bacilli smear and culture***
- The patient presents with clinical signs (persistent cough) and radiological findings (right upper lobe consolidation) highly suggestive of **active pulmonary tuberculosis**.
- **Sputum AFB smear** and **culture** are the **gold standard** for confirming active TB, allowing for **microbiological diagnosis** and crucial **drug susceptibility testing**.
*Perform interferon-gamma release assay (IGRA) test*
- **IGRA** is primarily used to diagnose **latent TB infection** and cannot reliably differentiate between latent infection and active disease.
- While BCG vaccination does not affect IGRA results, it is not the initial diagnostic test for a symptomatic patient with signs of **active pulmonary disease**.
*Perform Mantoux test with 2 TU tuberculin*
- The **Mantoux test** (Tuberculin Skin Test) is expected to be **false-positive** in this patient due to her recent **BCG vaccination**.
- Like IGRA, this test screens for **latent infection** and is insufficient for diagnosing **active clinical tuberculosis**.
*Arrange high-resolution CT chest to assess for tuberculosis*
- Although **HRCT** provides detailed anatomical imaging of lung pathology, it cannot provide a **microbiological diagnosis** or confirm the presence of *Mycobacterium tuberculosis*.
- Imaging should not delay the essential step of **sputum collection** for definitive diagnosis in a symptomatic patient with suspected active TB.
*Start empirical four-drug anti-tuberculosis therapy pending investigations*
- **Empirical treatment** is generally reserved for critically ill patients or those with high clinical suspicion where diagnostic samples are unobtainable or results are significantly delayed.
- Starting therapy prematurely can hinder **culture growth** and the ability to perform **drug susceptibility testing**, which is vital for effective treatment.
Question 97: A 65-year-old woman with type 2 diabetes presents with confusion, fever, and left-sided focal seizures. CT head shows a right temporal lobe lesion with surrounding oedema. Lumbar puncture shows: WBC 520/mm³ (70% lymphocytes), protein 0.9 g/L, glucose 3.8 mmol/L (plasma glucose 8.2 mmol/L), and red blood cells 850/mm³. PCR is positive for herpes simplex virus type 1. She is started on intravenous aciclovir. What additional immediate treatment is most likely to improve neurological outcome?
A. Intravenous dexamethasone 10 mg every 6 hours
B. Intravenous levetiracetam 1000 mg and continuation of prophylactic anti-epileptic therapy (Correct Answer)
C. Intravenous immunoglobulin 0.4 g/kg daily for 5 days
D. Urgent neurosurgical decompression
E. Plasma exchange therapy
Explanation: ***Intravenous levetiracetam 1000 mg and continuation of prophylactic anti-epileptic therapy***
- Seizures are a frequent complication in **Herpes Simplex Encephalitis (HSE)**, significantly impacting neurological outcomes, making immediate **seizure control** a primary goal.
- **Levetiracetam** is an effective anti-epileptic choice due to its rapid action, broad spectrum, and favorable drug interaction profile, crucial for patients with complex medical needs.
*Intravenous dexamethasone 10 mg every 6 hours*
- The routine use of **corticosteroids** like **dexamethasone** in **HSE** is controversial and not generally recommended, unlike in certain forms of bacterial meningitis.
- There is insufficient evidence to support that **corticosteroids** improve long-term neurological outcomes in viral encephalitis, and they might even potentially complicate viral clearance.
*Intravenous immunoglobulin 0.4 g/kg daily for 5 days*
- **Intravenous immunoglobulin (IVIG)** therapy is primarily indicated for **autoimmune encephalitis** and other immune-mediated neurological disorders, not for acute viral infections.
- **IVIG** has no established role in the direct treatment of active **HSV-1 encephalitis** as it does not target viral replication or acute infection.
*Urgent neurosurgical decompression*
- **Neurosurgical decompression** is a last-resort intervention reserved for life-threatening conditions such as severe **intracranial hypertension** or brain herniation.
- While there is focal oedema, the immediate management of **HSE** focuses on antiviral therapy and seizure control, with surgery considered only for extreme, refractory cases.
*Plasma exchange therapy*
- **Plasma exchange (PLEX)** is an immunomodulatory therapy used for conditions like **autoimmune neurological disorders** or specific demyelinating diseases.
- It is not indicated for the treatment of acute **viral encephalitis** and would not address the underlying HSV infection or its associated complications like seizures.
Question 98: A 27-year-old man from Nigeria presents with a 10-week history of progressive headache, vomiting, and personality change. He has been in the UK for 8 months. On examination, he is confused with GCS 13/15, temperature 37.8°C, and bilateral papilloedema. CT head shows hydrocephalus with basal enhancement. Lumbar puncture after normal coagulation: opening pressure 32 cmH₂O, WBC 180/mm³ (90% lymphocytes), protein 2.2 g/L, glucose 1.8 mmol/L (plasma glucose 5.4 mmol/L). India ink stain is positive. What is the most important initial investigation to guide treatment duration and prognosis?
A. Cryptococcal antigen titre in cerebrospinal fluid
B. HIV test with CD4 count (Correct Answer)
C. Mycobacterium tuberculosis PCR on cerebrospinal fluid
D. Cerebrospinal fluid culture for Cryptococcus species identification
E. Repeat lumbar puncture in 2 weeks to assess treatment response
Explanation: ***HIV test with CD4 count***- Confirmation of **HIV status** is the most critical next step because **cryptococcal meningitis** is an AIDS-defining illness, and management depends heavily on the level of **immunosuppression**.- The **CD4 count** guides the duration of antifungal therapy, the timing of **antiretroviral therapy (ART)** to avoid IRIS, and the necessity of **secondary prophylaxis**.*Cryptococcal antigen titre in cerebrospinal fluid*- While a high **cryptococcal antigen (CrAg) titre** (>1:1024) is associated with a higher **fungal burden** and poorer prognosis, it does not dictate the overall treatment framework as much as HIV status.- It is useful for diagnosis and monitoring, but it does not change the fundamental need to identify the underlying **immunodeficiency**.*Mycobacterium tuberculosis PCR on cerebrospinal fluid*- Although **basal enhancement** and hydrocephalus can be seen in **TB meningitis**, the **positive India ink** stain specifically identifies encapsulated yeasts, confirming Cryptococcus.- TB PCR is a valuable adjunct in endemic regions, but it would not be the primary guide for **treatment duration** of a confirmed fungal infection.*Cerebrospinal fluid culture for Cryptococcus species identification*- **CSF culture** is the gold standard for diagnosis and provides **antifungal susceptibility** testing, but it takes days to yield results.- While important for confirming the species (e.g., **C. neoformans** vs. **C. gattii**), it does not provide the same prognostic and longitudinal management guidance as knowing the patient's **HIV status**.*Repeat lumbar puncture in 2 weeks to assess treatment response*- A repeat LP is often performed at 2 weeks to confirm **CSF sterilization** (clearance of the fungus), but this is a monitoring step rather than an initial investigation.- Assessing **treatment response** is secondary to identifying the primary cause of the patient's susceptibility to such an **opportunistic infection**.
Question 99: A 32-year-old man presents to the emergency department with a 12-hour history of severe headache, fever of 39.2°C, and two episodes of vomiting. He has photophobia and neck stiffness. He had a splenectomy 5 years ago following a road traffic accident. Blood cultures are taken. What is the most appropriate immediate antibiotic regimen before lumbar puncture results are available?
A. Intravenous ceftriaxone 2 g
B. Intravenous cefotaxime 2 g and intravenous amoxicillin 2 g
C. Intravenous benzylpenicillin 2.4 g
D. Intravenous vancomycin 1 g and intravenous ceftriaxone 2 g (Correct Answer)
E. Intravenous meropenem 2 g
Explanation: ***Intravenous vancomycin 1 g and intravenous ceftriaxone 2 g***- Asplenic patients are at a significantly increased risk of severe infections with **encapsulated bacteria**, particularly **Streptococcus pneumoniae**, including strains that may be **penicillin-resistant**.- Empirical treatment for meningitis in asplenic individuals mandates a broad-spectrum approach, combining a **third-generation cephalosporin** (ceftriaxone) with **vancomycin** to cover potential resistant pneumococcal strains before sensitivities are known.*Intravenous ceftriaxone 2 g*- While ceftriaxone provides excellent coverage for **Neisseria meningitidis** and sensitive **Streptococcus pneumoniae**, it is insufficient alone for an asplenic patient.- It lacks coverage for **penicillin-resistant S. pneumoniae**, which is a major concern in individuals without a functional spleen.*Intravenous cefotaxime 2 g and intravenous amoxicillin 2 g*- Cefotaxime is similar to ceftriaxone but, like ceftriaxone alone, does not adequately cover **resistant S. pneumoniae** in this high-risk patient.- **Amoxicillin** is typically added for **Listeria monocytogenes** coverage, which is primarily a concern in the very young, very old, or severely immunocompromised (e.g., cell-mediated immunity deficits), rather than asplenic patients without other specific risk factors.*Intravenous benzylpenicillin 2.4 g*- Benzylpenicillin is effective against sensitive **S. pneumoniae** and **N. meningitidis** and is often used pre-hospital for suspected meningococcal disease.- It offers no coverage for **penicillin-resistant S. pneumoniae**, making it an inadequate choice for initial empirical management in an asplenic patient.*Intravenous meropenem 2 g*- Meropenem is a broad-spectrum carbapenem, often reserved for severe infections, multi-drug resistant pathogens, or patients with a severe **beta-lactam allergy**.- It is not the standard first-line empirical regimen for community-acquired meningitis in an asplenic patient when a combination of a third-generation cephalosporin and vancomycin is appropriate.
Question 100: A 48-year-old woman with smear-positive pulmonary tuberculosis has been on rifampicin, isoniazid, pyrazinamide, and ethambutol for 6 weeks. She now complains of reduced visual acuity and difficulty distinguishing red and green colours. Visual acuity testing shows deterioration from 6/6 to 6/18 bilaterally. What is the most likely cause and appropriate action?
A. Rifampicin-induced optic neuritis; stop rifampicin immediately and refer to ophthalmology
B. Ethambutol-induced optic neuropathy; stop ethambutol immediately and refer to ophthalmology (Correct Answer)
C. Isoniazid-induced peripheral neuropathy affecting optic nerve; add pyridoxine supplementation
D. Tuberculous choroiditis; continue treatment and add oral prednisolone
E. Pyrazinamide-induced optic neuritis; stop pyrazinamide and continue with three drugs
Explanation: ***Ethambutol-induced optic neuropathy; stop ethambutol immediately and refer to ophthalmology***- **Ethambutol** is well-known for causing **dose-dependent optic neuropathy**, typically presenting with decreased **visual acuity** and **red-green color blindness** (dyschromatopsia).- The medication must be **discontinued immediately** to prevent irreversible vision loss, followed by an urgent **ophthalmology referral** for formal assessment.*Rifampicin-induced optic neuritis; stop rifampicin immediately and refer to ophthalmology*- **Rifampicin** is not associated with optic neuritis; it is primarily known for causing **orange discoloration** of body fluids and potential **hepatotoxicity**.- Stopping the wrong medication would fail to address the toxic source and risk inadequate treatment of the **tuberculosis** infection.*Isoniazid-induced peripheral neuropathy affecting optic nerve; add pyridoxine supplementation*- **Isoniazid** typically causes **peripheral neuropathy** (numbness/tingling) rather than optic neuropathy; this is managed with **pyridoxine (Vitamin B6)**.- While Isoniazid can rarely cause optic issues, the classic presentation of **red-green color loss** is specifically diagnostic for ethambutol toxicity.*Tuberculous choroiditis; continue treatment and add oral prednisolone*- **Tuberculous choroiditis** would likely present with different ophthalmoscopic findings such as **choroidal tubercles** and is usually seen in disseminated or miliary TB.- The bilateral, symmetric deterioration of **color vision** while on RIPE therapy is a hallmark of drug toxicity rather than a new inflammatory infectious complication.*Pyrazinamide-induced optic neuritis; stop pyrazinamide and continue with three drugs*- **Pyrazinamide** is most commonly associated with **hyperuricemia** (leading to gout) and **hepatotoxicity**, not visual disturbances.- Optic neuritis is not a recognized side effect of pyrazinamide, so stopping it would be clinically inappropriate in this context.
