Master Internal Medicine
for DHA

What the DHA Tests in Internal Medicine

The DHA Internal Medicine exam tests your ability to manage common adult medical presentations in ambulatory and inpatient settings, with emphasis on evidence-based decision-making, guideline-directed therapy, and recognition of complications. You must demonstrate knowledge of diagnostic criteria (e.g., ACR/EULAR for rheumatoid arthritis, KDIGO for CKD staging), first-line pharmacotherapy (e.g., ACE inhibitors for hypertension with proteinuria, metformin for type 2 diabetes), and interpretation of key investigations (e.g., ECG for STEMI, ABG for respiratory failure). The exam focuses on clinical reasoning: choosing the next best step in diagnosis or management, identifying red flags (e.g., cauda equina syndrome, aortic dissection), and avoiding common pitfalls in chronic disease management (e.g., insulin initiation, anticoagulation in atrial fibrillation).

High-Yield Concepts

• Acute Coronary Syndrome (ACS) Management: For STEMI, door-to-balloon time <90 minutes; give aspirin 300 mg, ticagrelor 180 mg, and heparin (UFH 60 U/kg bolus). For NSTEMI, use GRACE score to guide early invasive vs. conservative strategy; start fondaparinux 2.5 mg SC daily if no urgent PCI. Dual antiplatelet therapy (aspirin + clopidogrel/ticagrelor) for 12 months post-ACS.
• Heart Failure with Reduced Ejection Fraction (HFrEF): First-line therapy: ACE inhibitor (e.g., ramipril 2.5 mg BD) or ARNI (sacubitril/valsartan) if tolerated, plus beta-blocker (bisoprolol, carvedilol) and spironolactone (25 mg OD). SGLT2 inhibitor (dapagliflozin 10 mg OD) added regardless of diabetes. LVEF ≤40% defines HFrEF.
• Diabetes Mellitus Type 2: Glycaemic Targets and Therapy: Target HbA1c <7% (53 mmol/mol) for most, <6.5% if young and no CVD. First-line: metformin (titrate to 2 g/day) if eGFR >30. If HbA1c >9% or symptomatic, consider insulin or GLP-1 agonist (liraglutide). SGLT2i (empagliflozin) or GLP-1 RA preferred if ASCVD or CKD.
• Chronic Kidney Disease (CKD) Staging and Management: Stage based on eGFR: G3a 45-59, G3b 30-44, G4 15-29, G5 <15. Albuminuria (A1 <30, A2 30-300, A3 >300 mg/g). BP target <130/80 mmHg; use ACEi/ARB if A2/A3. Refer to nephrology if eGFR <30 or rapid decline. Avoid NSAIDs, metformin if eGFR <30.
• Community-Acquired Pneumonia (CAP) Severity and Antibiotics: Use CURB-65 (Confusion, Urea >7, RR ≥30, BP <90/60, age ≥65). Score 0-1: treat at home with amoxicillin 500 mg TDS or doxycycline. Score 2: hospitalise; co-amoxiclav + clarithromycin. Score ≥3: severe; IV co-amoxiclav + clarithromycin or levofloxacin.
• Venous Thromboembolism (VTE) Diagnosis and Treatment: Use Wells score for DVT/PE; if low probability, do D-dimer. If high or D-dimer positive, do compression US or CTPA. Treat with rivaroxaban 15 mg BD for 21 days then 20 mg OD, or apixaban 10 mg BD for 7 days then 5 mg BD. LMWH (enoxaparin 1.5 mg/kg OD) if cancer.
• Rheumatoid Arthritis: Diagnosis and First-Line DMARDs: Diagnosis: ACR/EULAR 2010 criteria (joint involvement, serology, acute phase reactants, symptom duration). First-line: methotrexate 15-25 mg weekly + folic acid 5 mg weekly. If inadequate response, add sulfasalazine or leflunomide, then biologic (anti-TNF: adalimumab).
• Chronic Obstructive Pulmonary Disease (COPD) Exacerbation: Define exacerbation: increase in dyspnoea, sputum volume, or purulence. Treat with SABA (salbutamol via nebuliser), prednisolone 30-40 mg PO for 5 days, and antibiotics (amoxicillin or doxycycline) if purulent sputum. Consider NIV if pH <7.35 and PaCO2 >6.0 kPa.

Common Traps in Internal Medicine Questions

• Confusing STEMI with NSTEMI: any ST elevation >1 mm in limb leads or >2 mm in chest leads defines STEMI, not just 'new LBBB'.
• Using metformin in CKD stage 4 (eGFR <30) without stopping; it is contraindicated due to lactic acidosis risk.
• Forgetting to adjust digoxin dose in renal impairment; toxicity presents with nausea, visual disturbances, and arrhythmias.
• Misapplying CURB-65: a score of 2 does not automatically mean ICU; it means hospital-based care, not necessarily high dependency.
• Assuming all AF patients need anticoagulation; use CHA2DS2-VASc (men ≥2, women ≥3) to decide, and assess HAS-BLED for bleeding risk.
• Ordering a D-dimer in a high-probability VTE patient; it is only useful to rule out VTE in low/intermediate probability.

How to Revise Internal Medicine for the DHA

Prioritise high-yield topics: ACS, heart failure, diabetes, CKD, CAP, VTE, and COPD exacerbations. Questions are often scenario-based: a patient with chest pain, SOB, or abnormal labs — you must pick the next diagnostic step or best initial therapy. Memorise key cut-offs: CURB-65, CHA2DS2-VASc, eGFR stages, HbA1c targets, and antibiotic durations. Practice interpreting ABG (e.g., respiratory acidosis in COPD), ECG (STEMI vs. pericarditis), and basic lab trends (rising creatinine, D-dimer). Avoid over-investigation: know when to start treatment empirically (e.g., CAP, DVT). Focus on British/international guidelines (NICE, ESC, KDIGO) as DHA follows these conventions. Revise drug interactions (e.g., warfarin with amiodarone) and contraindications (e.g., beta-blockers in acute asthma).

Practise it: MedLumen has 127 Internal Medicine questions for the DHA, each with a full explanation and references.