# 37 ANTIMICROBIALS Antimicrobials are among the most heavily examined topics in MRCS Part A. Questions test three things repeatedly: mechanism of action, spectrum and indication, and major side effects. If you can place every drug into one of six mechanism boxes, predict which bugs it covers, and recall one or

👩‍⚕️ Electrolyte questions are exam gold. The Part A examiner does not care that you can recite a textbook — they care that you can spot the ECG, name the cation, choose the first-line fluid and avoid killing the patient with rapid correction. Learn the patterns below cold. Why electrolytes matter

# 36 CAUSATIVE PATHOGEN Why this topic matters "Match the bug to the scenario" is one of the highest-yield SBA patterns in MRCS Part A. The examiner gives you a one-line vignette — a sickle cell child with osteomyelitis, a watercress farmer with jaundice, an IVDU with cavitating

# 35 LUMBAR PUNCTURE Detailed notes Lumbar puncture (LP) is the deliberate introduction of a needle into the lumbar subarachnoid space to sample or measure cerebrospinal fluid (CSF). It is the workhorse diagnostic procedure for meningitis and a key tool in the workup of subarachnoid haemorrhage, demyelinating disease and Guillain-Barre

👩‍⚕️ Wound management is a guaranteed MRCS Part A topic. The examiners test it in three flavours: (1) the science — phases of healing, factors that derail them, and how scars go wrong; (2) the classification — clean through dirty, and which intention to close by; (3) the practical decisions — which suture, which

# 33 OTOLARYNGOLOGY ENT comes up reliably in MRCS Part A because it sits at the crossroads of head and neck anatomy, embryology, microbiology and acute surgical management. This chapter teaches the topic the way examiners test it: anatomy first, then the conditions, then the SBAs. Detailed notes Anatomy of the

👩‍⚕️ Thyroid is one of the most heavily examined organs in MRCS Part A. Examiners love it because it links anatomy (recurrent laryngeal nerve, parathyroids, blood supply), physiology (TSH–T4–T3 axis), pathology (autoimmune disease, four cancers with distinct biology) and surgery (four classic post-thyroidectomy complications). Master those four axes

# 31 NECK LUMPS Neck lumps are an examiner's playground. They reward candidates who can map a clinical sign to an anatomical compartment, then collapse the differential by age and behaviour of the lump. The trick is not memorising every lesion — it is having a reproducible system: where is

Detailed notes For MRCS Part A you are not tested on lymph physiology in detail — you are tested on which nodes drain which organ, because that determines where cancers metastasise and where surgeons must dissect. Two principles unlock most questions: 1. Lymphatics follow arteries — drainage of a gut segment mirrors

# 29 INTERPRETING BLOOD GASES ABG interpretation is one of the highest-yield skills in MRCS Part A. A single set of numbers can test physiology, pharmacology, surgical pathology and clinical reasoning at once — but every ABG is solved by the same five-step algorithm. Learn it cold. Normal values ParameterNormal