Most Tested Infectious Diseases Topics (MRCP Part 1)

TL;DR

This post highlights the most frequently tested infectious diseases topics (MRCP Part 1) — including HIV, tuberculosis, malaria, hepatitis and more. It shows which topics reappear in exams, provides a practical mini-case for practice and gives you a targeted checklist to apply in your revision.

Why this matters

The exam for MRCP Part 1 covers a wide range of specialties, and infectious diseases represent one of the consistently examined clinical topics. According to the official blueprint, Infectious Diseases alone contributes around 14 questions across the two papers. Royal Colleges of Physicians UK+1For candidates aiming to succeed, focusing on recurring, high-yield infectious disease blocks helps maximise efficiency. At Crack Medicine we build our resources — from the MRCP Part 1 overview to our Free MRCP MCQs and mock tests — to reflect precisely these recurring patterns.

10 High-Yield Infectious Diseases Topics

Below are ten topics that reliably feature in MRCP Part 1 and demand focused revision:

1. HIV and Opportunistic Infections – CD4 thresholds, prophylaxis, ART adverse effects.

2. Tuberculosis (TB) – Pulmonary vs extrapulmonary, drug resistance, diagnostic strategy.

3. Malaria & Other Parasitic Infections – Geography, smear morphology, severe criteria.

4. Hepatitis B & C – Serology interpretation, treatment indications, long-term complications.

5. Endocarditis & Device-associated Infections – Modified Duke criteria, common organisms, management.

6. Meningitis & Encephalitis – CSF findings, empiric antimicrobial regimens, viral vs bacterial features.

7. Pneumonia & Healthcare-associated Infection – Risk stratification (e.g., CURB-65), causative organisms by setting.

8. Sepsis & Septic Shock – Recognise early, apply bundles, antibiotic timing.

9. Sexually Transmitted Infections (STIs) – Syphilis serology, gonorrhoea vs chlamydia management.

10. Zoonoses & Travel Medicine – Typhoid, dengue, leptospirosis, and their key red-flags in clinical vignettes.

Focused Subtopics: 5 Key Areas

Here we elaborate on five of those topics with targeted revision points:

(1) HIV and Opportunistic Infections

• Memorise CD4 thresholds for common infections (e.g., <200 for PCP, <100 for Toxoplasma, <50 for MAC).

• Be prepared to recognise first-line ART regimens and major toxicities (e.g., tenofovir → renal/bone).

• Link clinical features to imaging and labs (e.g., PCP → bilateral ground-glass on CXR; raised LDH).

(2) Tuberculosis (TB)

• Know the standard four-drug regimen and hepatotoxicity risk (P > I > R).

• Remember that immunocompromised patients may have “normal” chest x-rays despite active TB.

• Distinguish latent vs active TB using IGRA, clinical context and imaging.

(3) Endocarditis

• Associate typical organisms with valve status (e.g., Staphylococcus aureus in native valves, Staph epidermidis in prosthetic).

• Memorise Modified Duke criteria: two major or one major + three minor etc.

• Spot extracardiac manifestations: Janeway lesions, Osler nodes, splinter haemorrhages.

(4) Hepatitis B & C

• Interpret serology: HBsAg, anti-HBs, anti-HBc (IgM vs IgG) — one question often revolves solely around this.

• Recognise complications such as cirrhosis and hepatocellular carcinoma, and indications for antiviral therapy (e.g., HBeAg +, high viral load).

• Be aware of drug classes in HCV (e.g., direct-acting antivirals) in newer questions.

(5) Malaria

• Identify Plasmodium falciparum via banana-shaped gametocytes, multilayer parasitaemia.

• Know treatment by severity: uncomplicated (artemether-lumefantrine) versus severe (IV artesunate).

• Remember travel history and region-specific resistance (e.g., Southeast Asia).

Mini-Case (Exam-Style)

Question: A 35-year-old man with known HIV infection (CD4 count 80/mm³) presents with fever and confusion. CSF analysis shows lymphocytosis, raised protein, low glucose; India-ink preparation demonstrates encapsulated yeast.

What is the most likely organism? A) Candida albicansB) Cryptococcus neoformansC) Histoplasma capsulatumD) Toxoplasma gondii

Answer: B) Cryptococcus neoformans Explanation: In an immunocompromised patient with features of meningoencephalitis and a positive India-ink, Cryptococcus neoformans is the likely pathogen. First-line treatment typically involves amphotericin B ± flucytosine induction, followed by fluconazole consolidation and maintenance.

Practical Study-Tip Checklist

• ✅ Set aside infection-specific days in your revision timetable — e.g., one day per week dedicated to infections.

• ✅ Use spaced-repetition flashcards for pathogenesis, microbiology, antimicrobials and diagnostics.

• ✅ Allocate weekly timed question sessions from a QBank and review incorrect answers immediately.

• ✅ Create summary tables (for example: HIV OI thresholds, hepatitis serology breakdown, TB drug side-effect ranking).

• ✅ Use the Free MRCP MCQs for infection blocks and systematically mark weak areas.

• ✅ Watch concise infection lectures (for example via our Crack Medicine lectures series) to consolidate understanding.

• ✅ Periodically sit full system-based mock tests via Start a mock test and review performance analytics to detect recurring weak areas.

Common Pitfalls & How to Fix Them

• Pitfall: Trying to memorise exhaustive lists without context. Fix: Anchor facts in clinical vignettes — e.g., link CD4 threshold to a case of PCP.

• Pitfall: Misinterpreting viral serology (hepatitis, HIV).Fix: Draw and label the serology sequence visually and practise multiple examples.

• Pitfall: Neglecting tropical/zoonotic diseases (assuming ‘UK only’ scenarios).Fix: Include one travel-medicine case in each weekly session — ensure exposure.

• Pitfall: Skipping antimicrobials and pharmacology in infection questions. Fix: Always pair pathogen recognition with first-line treatment, key side-effects and resistance patterns.

• Pitfall: Assuming clinical management questions won’t arise (focus only on microbiology).Fix: Practice full scenario questions that include diagnosis, management and prognosis steps.

FAQs

Q1: How many infection questions appear in MRCP Part 1?

According to the official blueprint, “Infectious diseases” is allocated around 14 questions across the two papers. Royal Colleges of Physicians UK

Q2: Are travel/zoonotic infections worth focusing on for MRCP Part 1?

Yes — they frequently appear as clinical vignettes especially in international settings or in patients with travel history; you should include them in your high-yield list.

Q3: What is the best way to approach infection revision for MRCP Part 1?Balance microbiology (pathogens, diagnostics), clinical medicine (presentations, management) and pharmacology (antimicrobials, prophylaxis). Use QBank practice + spaced-repetition + mock analytics.

Q4: Should I rely solely on question banks for infectious diseases?

No — while QBanks are essential, you must also review core textbooks/notes to understand pathophysiology and not treat the topic as rote memorisation.

Q5: How does Crack Medicine support infection revision for MRCP Part 1?

Our platform offers targeted lectures on infectious diseases, a large infection block in our QBank, and regular mock-test opportunities with performance tracking.

Ready to start?

Mastering infectious diseases is a strategic step in your MRCP Part 1 journey. Focus your revision on the most frequently tested infectious diseases topics (MRCP Part 1) we’ve outlined, and use repeated QBank practice, mock analytics and active recall methods. Visit our MRCP Part 1 overview, begin with our Free MRCP MCQs, and consider sitting a mock test to benchmark your infection-topic performance. Let’s elevate your revision from broad to targeted — your success is nearer than you think.

Sources

• Federation of the Royal Colleges of Physicians of the UK – MRCP Part 1 Examination Format. Royal Colleges of Physicians UK+1

• StudyMRCP – Subject-wise weightage for MRCP Part 1. Study MRCP

• Scribd – Infectious Diseases and STIs for MRCP revision. Scribd

• Reddit discussion – MRCP Part 1 revision strategies.