PLAB 2: Mastering Common Infectious Disease Guidelines

PLAB 2: Mastering Common Infectious Disease Guidelines for OSCE Success

As an International Medical Graduate (IMG) preparing for the PLAB 2 exam, you're acutely aware that success hinges not just on theoretical knowledge, but on its practical application in a UK clinical context. A significant portion of this involves understanding and adhering to current Medical Guidelines, especially when it comes to common presentations of Infectious Diseases. These scenarios are frequently tested in PLAB 2 OSCEs, demanding a confident, guideline-driven approach.

In the UK, guidelines from bodies like NICE (National Institute for Health and Care Excellence), Public Health England (now UKHSA), and various professional societies are the bedrock of clinical practice. For PLAB 2, you need to demonstrate that you can manage common infections safely and effectively, mirroring the practice of a Foundation Year doctor.

Let's delve into some high-yield infectious disease scenarios and how to approach them with UK guidelines in mind for your PLAB 2 OSCEs:

1. Community-Acquired Pneumonia (CAP)

CAP is a classic presentation. Your OSCE station might involve a patient presenting with cough, fever, and shortness of breath. Here's what the examiner expects:

• History Taking: Elicit key symptoms (onset, duration, sputum, chest pain, dyspnoea), risk factors (smoking, comorbidities, recent travel/contacts), and red flags (confusion, severe breathlessness, haemoptysis).

• Examination: Focus on respiratory (chest expansion, percussion, auscultation – crackles, bronchial breathing), vital signs (temperature, respiratory rate, heart rate, blood pressure, oxygen saturation).

• Investigations (Initial): For PLAB 2, think about the immediate steps. A CXR is crucial for diagnosis. Bloods like FBC, CRP, U&Es are often mentioned. Crucially, assess severity using the CURB-65 score (Confusion, Urea >7 mmol/L, Respiratory rate ≥30/min, Blood pressure <90/60 mmHg, Age ≥65 years). Each criterion scores 1 point.

• Management (Guideline-driven):

  • Low severity (CURB-65 0-1): Oral Amoxicillin for 5 days. If penicillin allergic, Doxycycline or Clarithromycin.

  • Moderate severity (CURB-65 2): Consider hospital admission. Oral Amoxicillin + Clarithromycin or Doxycycline, or IV Benzylpenicillin + Clarithromycin for 7-10 days.

  • High severity (CURB-65 ≥3): Urgent hospital admission. IV Cefotaxime or Ceftriaxone + Clarithromycin for 7-10 days.

• Safety Netting: Emphasise follow-up, red flag symptoms for re-attendance (worsening symptoms, new symptoms), and cessation of smoking.

2. Urinary Tract Infection (UTI)

UTIs are incredibly common, especially in women. The OSCE might present a patient with dysuria, frequency, and suprapubic pain.

• History Taking: Differentiate between lower UTI (cystitis) and upper UTI (pyelonephritis – flank pain, fever, systemic upset). Ask about recurrent UTIs, sexual activity, new partners, and contraceptive methods (diaphragm/spermicide can increase risk).

• Examination: Abdominal palpation (suprapubic tenderness), CVA tenderness if pyelonephritis suspected. Vital signs if systemic symptoms present.

• Investigations: Urine dipstick (nitrites, leukocytes, blood) and sending a Mid-Stream Urine (MSU) for culture and sensitivity are key.

• Management (Guideline-driven):

  • Uncomplicated lower UTI in non-pregnant women: First-line: Nitrofurantoin (3 days) or Trimethoprim (3 days). Pivmecillinam is an alternative. Avoid trimethoprim if high local resistance rates.

  • Pregnant women: Always send an MSU. Treat with Nitrofurantoin (avoid near term), Cephalexin, or Amoxicillin for 7 days, even if asymptomatic bacteriuria.

  • Men/Children/Catheter-associated UTI/Pyelonephritis: Always send MSU and treat for 7-10 days, usually with broader spectrum antibiotics like Co-amoxiclav, Ciprofloxacin (consider resistance), or Cefalexin, adjusting based on sensitivities. Refer pyelonephritis for specialist assessment.

• Safety Netting: Advise fluid intake, paracetamol for discomfort, return if symptoms worsen or don't improve after 48 hours.

3. Cellulitis

Cellulitis can range from a mild localized infection to a rapidly spreading, severe condition. An OSCE might involve a patient with a red, hot, swollen leg.

• History Taking: Onset, progression, pain, fever, recent skin breaks (cuts, insect bites, fungal infections like tinea pedis, ulcers), previous episodes, comorbidities (diabetes, lymphoedema, peripheral vascular disease).

• Examination: Describe the affected area – erythema, swelling, warmth, tenderness. Look for an entry point. Assess for systemic signs (fever, tachycardia). Differentiate from DVT (check for pitting oedema, calf tenderness, Homan's sign – though less reliable). Mark the borders of the redness to monitor spread.

• Investigations: Bloods (FBC, CRP) if systemic involvement or severe. Consider a wound swab if there's a clear breach in the skin or pus.

• Management (Guideline-driven):

  • Uncomplicated/Mild: Oral Flucloxacillin for 5-7 days. If penicillin allergic: Clarithromycin or Doxycycline.

  • Severe/Systemic symptoms/Rapidly spreading: Hospital admission for IV antibiotics like Flucloxacillin or Co-amoxiclav. Consider specialist input.

  • Leg elevation and analgesia are important adjunctive measures.

• Safety Netting: Advise return if worsening symptoms, provide pain relief advice, and discuss prevention strategies for recurrent cellulitis (e.g., treating tinea pedis, moisturising skin).

Key Takeaways for PLAB 2:

• Know the First-Line Antibiotics: Be precise with drug names, doses (though often not tested, knowing common choices is key), and durations.

• Understand Allergy Alternatives: Always have a backup plan for penicillin-allergic patients.

• Severity Assessment is Crucial: Tools like CURB-65 help guide management decisions, reflecting safe practice.

• Safety Netting is Non-Negotiable: Empowering the patient with information on when to seek further help is a cornerstone of UK practice.

• Referral Pathways: Know when to admit or refer to a specialist (e.g., severe infections, non-responders, pyelonephritis).

Practising these scenarios with a focus on national guidelines will not only help you ace your PLAB 2 OSCEs but also prepare you for real-world clinical practice in the NHS. Good luck!