MRCP(UK) Part 1 cheat sheet

STEMI: ST elevation of at least 1 mm in two contiguous limb leads, or at least 2 mm in V2-V3 in men aged 40 or over; posterior infarction shows horizontal ST depression with tall R waves in V1-V3.

Heart failure is classified by ejection fraction as reduced (40% or less), mildly reduced (41-49%) and preserved (50% or more).

Acute pericarditis: widespread concave (saddle-shaped) ST elevation with PR depression, and reciprocal PR elevation in lead aVR.

Severe aortic stenosis: valve area below 1.0 cm2, mean gradient 40 mmHg or more, or peak jet velocity 4 m/s or more.

Atrial fibrillation: anticoagulate when CHA2DS2-VASc is 2 or more in men or 3 or more in women; DOACs are preferred except with mechanical valves or moderate-to-severe mitral stenosis.

Hypertrophic cardiomyopathy: asymmetric septal hypertrophy with systolic anterior motion of the mitral valve; the systolic murmur loudens with Valsalva and standing and softens with squatting.

Infective endocarditis: take three sets of blood cultures from separate sites before starting antibiotics; diagnosis uses the modified Duke criteria combining microbiology and echocardiography.

Cardiac tamponade: Beck's triad (hypotension, raised JVP, muffled heart sounds), pulsus paradoxus above 10 mmHg and electrical alternans; treat with urgent pericardiocentesis.

Asthma: a post-bronchodilator rise in FEV1 of at least 12% and at least 200 mL from baseline demonstrates reversible airflow obstruction.

COPD: a post-bronchodilator FEV1/FVC ratio below 0.70 confirms persistent airflow obstruction; severity is graded by FEV1 percentage predicted.

Metabolic acidosis: expected PaCO2 = 1.5 x bicarbonate + 8 +/- 2 kPa-derived value (Winter's formula); a measured PaCO2 outside this range indicates a second disorder.

Light's criteria: pleural fluid is an exudate if the protein ratio exceeds 0.5, the LDH ratio exceeds 0.6, or pleural LDH exceeds two-thirds of the serum upper limit of normal.

CURB-65: confusion, urea above 7 mmol/L, respiratory rate 30 or more, systolic BP below 90 or diastolic 60 or less, and age 65 or over; a score of 2 or more usually warrants admission.

Suspected pulmonary embolism: an age-adjusted D-dimer can exclude disease in low or intermediate probability patients; CTPA is first-line imaging, with V/Q scanning if contrast is contraindicated.

Sarcoidosis: bilateral hilar lymphadenopathy, non-caseating granulomas, raised serum ACE and hypercalcaemia; erythema nodosum with hilar adenopathy (Lofgren syndrome) carries a good prognosis.

Latent tuberculosis: a positive interferon-gamma release assay or tuberculin skin test without clinical or radiological disease; IGRA results are not affected by prior BCG vaccination.

Coeliac disease: request anti-tTG IgA together with total IgA, since IgA deficiency causes false negatives; duodenal biopsy shows villous atrophy, crypt hyperplasia and intraepithelial lymphocytes.

Ulcerative colitis causes continuous mucosal inflammation extending proximally from the rectum; Crohn's disease shows skip lesions, transmural inflammation, non-caseating granulomas and perianal disease.

Acute pancreatitis is diagnosed by two of three features: characteristic epigastric pain, lipase or amylase more than three times the upper limit of normal, and typical imaging.

Hepatorenal syndrome: functional renal impairment in cirrhosis with ascites, no sustained response to volume expansion, bland urinary sediment and urine sodium below 10 mmol/L.

Hepatitis B serology: HBsAg indicates current infection, anti-HBs immunity, HBeAg with high HBV DNA high infectivity, and anti-HBc IgM acute or recent infection.

Acute variceal bleeding: terlipressin plus prophylactic antibiotics plus endoscopic band ligation; a transjugular intrahepatic portosystemic shunt is used for refractory bleeding.

Autoimmune hepatitis: raised IgG with ANA and/or anti-smooth muscle antibody, interface hepatitis on biopsy; treat with prednisolone and azathioprine.

Wilson disease: low caeruloplasmin, raised 24-hour urinary copper, Kayser-Fleischer rings and Coombs-negative haemolysis; chelate with penicillamine or trientine.

Diabetes is diagnosed by HbA1c 48 mmol/mol or more, fasting glucose 7.0 mmol/L or more, two-hour OGTT glucose 11.1 mmol/L or more, or a random glucose of 11.1 mmol/L or more with symptoms.

Diabetic ketoacidosis: glucose above 11 mmol/L, venous pH below 7.3, bicarbonate below 15 mmol/L and ketonaemia; treat with isotonic saline, fixed-rate intravenous insulin and potassium replacement.

Primary hyperaldosteronism: raised aldosterone-to-renin ratio with hypertension and hypokalaemia; confirm by saline suppression, then adrenal CT and adrenal vein sampling.

Graves' disease: suppressed TSH, raised free T4, TSH-receptor antibodies, diffuse goitre and ophthalmopathy; treat with carbimazole, radioiodine or thyroidectomy.

Cushing's syndrome screening: overnight 1 mg dexamethasone suppression test, 24-hour urinary free cortisol, or late-night salivary cortisol; a failed test requires confirmatory testing.

Short Synacthen test: a peak cortisol below 500 nmol/L at 30 or 60 minutes after tetracosactide suggests adrenal insufficiency.

SIADH: euvolaemic hypotonic hyponatraemia with urine osmolality above 100 mOsm/kg and urine sodium above 30 mmol/L; first-line treatment is fluid restriction.

Phaeochromocytoma: plasma free metanephrines are the initial test; give alpha-blockade before beta-blockade to avoid a hypertensive crisis.

KDIGO acute kidney injury: creatinine rise of 26 micromol/L or more within 48 hours, or to 1.5 times baseline within 7 days, or urine output below 0.5 mL/kg/h for 6 hours.

CKD is staged by GFR category G1 (90 or more) to G5 (below 15) combined with albuminuria A1 (below 3), A2 (3-30) and A3 (above 30 mg/mmol).

Hyperkalaemia with ECG changes: give intravenous calcium gluconate first for membrane stabilisation, then insulin-dextrose and nebulised salbutamol, then remove potassium by dialysis or binders.

Corrected calcium (mmol/L) = measured calcium + 0.02 x (40 - serum albumin in g/L).

Nephrotic syndrome: proteinuria above 3.5 g/24 h, hypoalbuminaemia, oedema and hyperlipidaemia; nephritic syndrome shows haematuria with red cell casts, hypertension and oliguria.

Rhabdomyolysis: creatine kinase more than five times the upper limit of normal, myoglobinuria, acute kidney injury and hyperkalaemia; treat with aggressive intravenous crystalloid.

Urgent dialysis indications: refractory acidosis, refractory hyperkalaemia, fluid overload, dialysable toxin ingestion and uraemic pericarditis or encephalopathy.

Renal artery stenosis: creatinine rise of more than 30% after starting an ACE inhibitor or ARB, flash pulmonary oedema and an abdominal bruit; confirm with CT or MR angiography.

Glasgow Coma Scale: eyes 4, verbal 5, motor 6; a total of 8 or less indicates the need for airway protection.

Ischaemic stroke: intravenous thrombolysis within 4.5 hours of onset; mechanical thrombectomy up to 6 hours, and in selected patients with salvageable tissue up to 24 hours.

Bacterial meningitis CSF: neutrophil predominance, glucose below 60% of the blood value, protein above 1 g/L; viral meningitis shows lymphocytosis with normal glucose.

Subarachnoid haemorrhage: CT within 6 hours of onset is highly sensitive; if later and CT is negative, lumbar puncture for xanthochromia at 12 hours or more is required.

Myasthenia gravis: fatigable weakness, anti-acetylcholine receptor antibodies in most patients, decremental response on repetitive nerve stimulation, and association with thymoma.

Guillain-Barre syndrome: progressive ascending weakness with areflexia and albuminocytological dissociation in CSF; treat with intravenous immunoglobulin or plasma exchange.

Parkinson's disease: bradykinesia plus rigidity or rest tremor, asymmetric onset and a good response to levodopa.

Multiple sclerosis: lesions disseminated in space and time, typically periventricular, juxtacortical, infratentorial and spinal cord on MRI, with CSF oligoclonal bands supporting the diagnosis.

Gout: needle-shaped, negatively birefringent monosodium urate crystals in synovial fluid; pseudogout shows rhomboid, positively birefringent calcium pyrophosphate crystals.

Rheumatoid arthritis: anti-CCP is more specific than rheumatoid factor; DMARD therapy should start within three months of diagnosis.

Giant cell arteritis: age 50 or over, new headache, jaw claudication, scalp tenderness and visual loss with ESR typically above 50 mm/h; start high-dose prednisolone immediately.

SLE: ANA is sensitive but non-specific, anti-dsDNA and anti-Smith are specific, and anti-histone antibodies suggest drug-induced lupus.

Ankylosing spondylitis: inflammatory back pain, sacroiliitis on imaging, HLA-B27 positivity in most patients, and syndesmophytes producing a bamboo spine.

Polymyalgia rheumatica: age over 50, bilateral shoulder and hip girdle pain and stiffness, raised ESR or CRP, and rapid response to prednisolone 15 mg daily.

Sjogren's syndrome: dry eyes and mouth, anti-Ro and anti-La antibodies, positive Schirmer test, and an increased risk of B-cell lymphoma.

Septic arthritis: synovial white cell count usually above 50,000/microlitre; urgent aspiration and intravenous antibiotics are required.

Iron deficiency: low ferritin, microcytosis, raised total iron-binding capacity and low transferrin saturation; ferritin is an acute phase reactant, so a normal value does not exclude deficiency during inflammation.

Anaemia of chronic disease: low serum iron with low total iron-binding capacity and normal or raised ferritin.

Vitamin B12 deficiency: macrocytic anaemia with raised methylmalonic acid and homocysteine; folate deficiency raises homocysteine alone.

CML carries t(9;22) BCR-ABL1 and is treated with imatinib; acute promyelocytic leukaemia carries t(15;17) PML-RARA and is treated with all-trans retinoic acid.

Disseminated intravascular coagulation: prolonged PT and APTT, thrombocytopenia, low fibrinogen and raised D-dimers; treat the underlying cause with supportive blood products.

Thrombotic thrombocytopenic purpura: microangiopathic haemolytic anaemia, thrombocytopenia, neurological and renal features and fever with ADAMTS13 deficiency; treat with plasma exchange.

Heparin-induced thrombocytopenia: platelet count falls by more than 50% at 5-10 days with paradoxical thrombosis; stop heparin and start argatroban or fondaparinux.

Myeloma: CRAB features (hypercalcaemia, renal failure, anaemia, bone lesions), a paraprotein on electrophoresis and marrow plasma cells above 10%.

Malaria: ring forms on thick film; Plasmodium falciparum shows banana-shaped gametocytes; severe disease is treated with intravenous artesunate.

Typhoid fever: step-ladder fever, relative bradycardia, rose spots and hepatosplenomegaly; diagnose with blood culture and treat with ceftriaxone or azithromycin.

Dengue: thrombocytopenia with rising haematocrit indicates plasma leakage; avoid NSAIDs and aspirin because of bleeding risk.

HIV: a fourth-generation combined antigen-antibody assay is used for screening and HIV RNA for confirmation; antiretroviral therapy is started regardless of CD4 count.

Pneumocystis jirovecii pneumonia: CD4 count below 200 cells/microlitre, ground-glass infiltrates and raised LDH; treat and prophylax with co-trimoxazole.

Syphilis: treat with benzylpenicillin; the Jarisch-Herxheimer reaction of fever and rigors follows the first dose and is managed supportively.

Leptospirosis (Weil's disease): jaundice, acute kidney injury, haemorrhage and myocarditis after contact with contaminated water; treat with benzylpenicillin or doxycycline.

Streptococcus bovis bacteraemia or endocarditis warrants colonoscopy, because of the association with colorectal adenoma and carcinoma.

Zero-order kinetics occur with phenytoin, ethanol and high-dose salicylates; elimination is constant, so small dose increases cause disproportionate rises in plasma concentration.

CYP inducers include rifampicin, carbamazepine, phenytoin, phenobarbital and St John's wort; they lower concentrations of warfarin, oestrogens and many antiepileptics.

CYP3A4 inhibitors include macrolides other than azithromycin, azole antifungals, verapamil, diltiazem, ritonavir and grapefruit juice.

Lithium has a therapeutic range of 0.6-1.0 mmol/L; toxicity risk rises with dehydration, NSAIDs, thiazides and ACE inhibitors, and levels are taken 12 hours after the dose.

Digoxin toxicity causes nausea, yellow-green visual disturbance and arrhythmias, is precipitated by hypokalaemia and renal impairment, and is treated with digoxin-specific antibody fragments.

Warfarin inhibits vitamin K epoxide reductase and is monitored by INR; reverse with vitamin K plus prothrombin complex concentrate in major bleeding.

Steady state is reached after four to five half-lives; loading dose = (volume of distribution x target concentration) / bioavailability.

Aminoglycosides and vancomycin need therapeutic drug monitoring because of their narrow therapeutic index and nephrotoxicity.

Psoriasis: well-demarcated erythematous plaques with silvery scale on extensor surfaces, Auspitz sign and Koebner phenomenon; first-line treatment is a topical corticosteroid with a vitamin D analogue.

Pemphigus vulgaris: flaccid intraepidermal blisters, positive Nikolsky sign and IgG against desmoglein 1 and 3; treat with systemic corticosteroids plus a steroid-sparing agent.

Bullous pemphigoid: tense subepidermal blisters in older adults with linear IgG and C3 at the basement membrane and antibodies to BP180 and BP230.

Dermatitis herpetiformis: itchy vesicles on extensor surfaces with granular IgA in the dermal papillae, associated with coeliac disease, treated with dapsone and a gluten-free diet.

Melanoma: assessed by the ABCDE criteria, with Breslow thickness the strongest prognostic factor and the determinant of excision margins and sentinel node biopsy.

Stevens-Johnson syndrome involves 10-30% body surface area and toxic epidermal necrolysis more than 30%; both are usually drug-induced, whereas erythema multiforme usually follows herpes simplex.

Porphyria cutanea tarda: fragile skin and blisters on sun-exposed areas with uroporphyrinuria, associated with alcohol, hepatitis C and haemochromatosis.

Lichen planus: pruritic, purple, polygonal planar papules with Wickham striae, affecting wrists, ankles and oral mucosa.

Delirium: acute onset with fluctuating course and inattention, screened with the 4AT; the hypoactive subtype is frequently mistaken for depression or dementia.

Falls in older adults require multifactorial assessment including postural blood pressure, ECG, vision, gait and balance, continence and a full medication review.

High anticholinergic burden and polypharmacy worsen cognition and cause urinary retention, constipation and falls; STOPP/START and Beers criteria guide deprescribing.

Dementia subtypes: Alzheimer's (early memory loss), vascular (stepwise decline with focal signs), Lewy body (fluctuations, visual hallucinations, parkinsonism, neuroleptic sensitivity), frontotemporal (behavioural or language variants).

Frailty is identified by the Fried phenotype (weight loss, exhaustion, low activity, slow gait, weakness) or by a cumulative deficit index.

Syncope red flags: exertional syncope, family history of sudden cardiac death, abnormal ECG or structural heart disease; these require admission and cardiac assessment.

Pressure ulcers are risk-assessed with the Braden scale and staged 1-4; prevention uses repositioning, pressure-relieving surfaces and nutritional support.

Hypothermia below 35 degrees Celsius: look for sepsis, myxoedema, hypoglycaemia, stroke and drug toxicity; rewarm gradually while treating the underlying cause.

STEMI: ST elevation of at least 1 mm in two contiguous limb leads, or at least 2 mm in V2-V3 in men aged 40 or over; posterior infarction shows horizontal ST depression with tall R waves in V1-V3.

Heart failure is classified by ejection fraction as reduced (40% or less), mildly reduced (41-49%) and preserved (50% or more).

Acute pericarditis: widespread concave (saddle-shaped) ST elevation with PR depression, and reciprocal PR elevation in lead aVR.

Severe aortic stenosis: valve area below 1.0 cm2, mean gradient 40 mmHg or more, or peak jet velocity 4 m/s or more.

Atrial fibrillation: anticoagulate when CHA2DS2-VASc is 2 or more in men or 3 or more in women; DOACs are preferred except with mechanical valves or moderate-to-severe mitral stenosis.

Hypertrophic cardiomyopathy: asymmetric septal hypertrophy with systolic anterior motion of the mitral valve; the systolic murmur loudens with Valsalva and standing and softens with squatting.

Infective endocarditis: take three sets of blood cultures from separate sites before starting antibiotics; diagnosis uses the modified Duke criteria combining microbiology and echocardiography.

Cardiac tamponade: Beck's triad (hypotension, raised JVP, muffled heart sounds), pulsus paradoxus above 10 mmHg and electrical alternans; treat with urgent pericardiocentesis.

Asthma: a post-bronchodilator rise in FEV1 of at least 12% and at least 200 mL from baseline demonstrates reversible airflow obstruction.

COPD: a post-bronchodilator FEV1/FVC ratio below 0.70 confirms persistent airflow obstruction; severity is graded by FEV1 percentage predicted.

Metabolic acidosis: expected PaCO2 = 1.5 x bicarbonate + 8 +/- 2 (Winter's formula); a measured PaCO2 outside this range indicates a second disorder.

Light's criteria: pleural fluid is an exudate if the protein ratio exceeds 0.5, the LDH ratio exceeds 0.6, or pleural LDH exceeds two-thirds of the serum upper limit of normal.

CURB-65: confusion, urea above 7 mmol/L, respiratory rate 30 or more, systolic BP below 90 or diastolic 60 or less, and age 65 or over; a score of 2 or more usually warrants admission.

Suspected pulmonary embolism: an age-adjusted D-dimer can exclude disease in low or intermediate probability patients; CTPA is first-line imaging, with V/Q scanning if contrast is contraindicated.

Sarcoidosis: bilateral hilar lymphadenopathy, non-caseating granulomas, raised serum ACE and hypercalcaemia; erythema nodosum with hilar adenopathy (Lofgren syndrome) carries a good prognosis.

Latent tuberculosis: a positive interferon-gamma release assay or tuberculin skin test without clinical or radiological disease; IGRA results are not affected by prior BCG vaccination.

Coeliac disease: request anti-tTG IgA together with total IgA, since IgA deficiency causes false negatives; duodenal biopsy shows villous atrophy, crypt hyperplasia and intraepithelial lymphocytes.

Ulcerative colitis causes continuous mucosal inflammation extending proximally from the rectum; Crohn's disease shows skip lesions, transmural inflammation, non-caseating granulomas and perianal disease.

Acute pancreatitis is diagnosed by two of three features: characteristic epigastric pain, lipase or amylase more than three times the upper limit of normal, and typical imaging.

Hepatorenal syndrome: functional renal impairment in cirrhosis with ascites, no sustained response to volume expansion, bland urinary sediment and urine sodium below 10 mmol/L.

Hepatitis B serology: HBsAg indicates current infection, anti-HBs immunity, HBeAg with high HBV DNA high infectivity, and anti-HBc IgM acute or recent infection.

Acute variceal bleeding: terlipressin plus prophylactic antibiotics plus endoscopic band ligation; a transjugular intrahepatic portosystemic shunt is used for refractory bleeding.

Autoimmune hepatitis: raised IgG with ANA and/or anti-smooth muscle antibody, interface hepatitis on biopsy; treat with prednisolone and azathioprine.

Wilson disease: low caeruloplasmin, raised 24-hour urinary copper, Kayser-Fleischer rings and Coombs-negative haemolysis; chelate with penicillamine or trientine.

Diabetes is diagnosed by HbA1c 48 mmol/mol or more, fasting glucose 7.0 mmol/L or more, two-hour OGTT glucose 11.1 mmol/L or more, or a random glucose of 11.1 mmol/L or more with symptoms.

Diabetic ketoacidosis: glucose above 11 mmol/L, venous pH below 7.3, bicarbonate below 15 mmol/L and ketonaemia; treat with isotonic saline, fixed-rate intravenous insulin and potassium replacement.

Primary hyperaldosteronism: raised aldosterone-to-renin ratio with hypertension and hypokalaemia; confirm by saline suppression, then adrenal CT and adrenal vein sampling.

Graves' disease: suppressed TSH, raised free T4, TSH-receptor antibodies, diffuse goitre and ophthalmopathy; treat with carbimazole, radioiodine or thyroidectomy.

Cushing's syndrome screening: overnight 1 mg dexamethasone suppression test, 24-hour urinary free cortisol, or late-night salivary cortisol; a failed test requires confirmatory testing.

Short Synacthen test: a peak cortisol below 500 nmol/L at 30 or 60 minutes after tetracosactide suggests adrenal insufficiency.

SIADH: euvolaemic hypotonic hyponatraemia with urine osmolality above 100 mOsm/kg and urine sodium above 30 mmol/L; first-line treatment is fluid restriction.

Phaeochromocytoma: plasma free metanephrines are the initial test; give alpha-blockade before beta-blockade to avoid a hypertensive crisis.

KDIGO acute kidney injury: creatinine rise of 26 micromol/L or more within 48 hours, or to 1.5 times baseline within 7 days, or urine output below 0.5 mL/kg/h for 6 hours.

CKD is staged by GFR category G1 (90 or more) to G5 (below 15) combined with albuminuria A1 (below 3), A2 (3-30) and A3 (above 30 mg/mmol).

Hyperkalaemia with ECG changes: give intravenous calcium gluconate first for membrane stabilisation, then insulin-dextrose and nebulised salbutamol, then remove potassium by dialysis or binders.

Corrected calcium (mmol/L) = measured calcium + 0.02 x (40 - serum albumin in g/L).

Nephrotic syndrome: proteinuria above 3.5 g/24 h, hypoalbuminaemia, oedema and hyperlipidaemia; nephritic syndrome shows haematuria with red cell casts, hypertension and oliguria.

Rhabdomyolysis: creatine kinase more than five times the upper limit of normal, myoglobinuria, acute kidney injury and hyperkalaemia; treat with aggressive intravenous crystalloid.

Urgent dialysis indications: refractory acidosis, refractory hyperkalaemia, fluid overload, dialysable toxin ingestion and uraemic pericarditis or encephalopathy.

Renal artery stenosis: creatinine rise of more than 30% after starting an ACE inhibitor or ARB, flash pulmonary oedema and an abdominal bruit; confirm with CT or MR angiography.

Glasgow Coma Scale: eyes 4, verbal 5, motor 6; a total of 8 or less indicates the need for airway protection.

Ischaemic stroke: intravenous thrombolysis within 4.5 hours of onset; mechanical thrombectomy up to 6 hours, and in selected patients with salvageable tissue up to 24 hours.

Bacterial meningitis CSF: neutrophil predominance, glucose below 60% of the blood value, protein above 1 g/L; viral meningitis shows lymphocytosis with normal glucose.

Subarachnoid haemorrhage: CT within 6 hours of onset is highly sensitive; if later and CT is negative, lumbar puncture for xanthochromia at 12 hours or more is required.

Myasthenia gravis: fatigable weakness, anti-acetylcholine receptor antibodies in most patients, decremental response on repetitive nerve stimulation, and association with thymoma.

Guillain-Barre syndrome: progressive ascending weakness with areflexia and albuminocytological dissociation in CSF; treat with intravenous immunoglobulin or plasma exchange.

Parkinson's disease: bradykinesia plus rigidity or rest tremor, asymmetric onset and a good response to levodopa.

Multiple sclerosis: lesions disseminated in space and time, typically periventricular, juxtacortical, infratentorial and spinal cord on MRI, with CSF oligoclonal bands supporting the diagnosis.

Gout: needle-shaped, negatively birefringent monosodium urate crystals in synovial fluid; pseudogout shows rhomboid, positively birefringent calcium pyrophosphate crystals.

Rheumatoid arthritis: anti-CCP is more specific than rheumatoid factor; DMARD therapy should start within three months of diagnosis.

Giant cell arteritis: age 50 or over, new headache, jaw claudication, scalp tenderness and visual loss with ESR typically above 50 mm/h; start high-dose prednisolone immediately.

SLE: ANA is sensitive but non-specific, anti-dsDNA and anti-Smith are specific, and anti-histone antibodies suggest drug-induced lupus.

Ankylosing spondylitis: inflammatory back pain, sacroiliitis on imaging, HLA-B27 positivity in most patients, and syndesmophytes producing a bamboo spine.

Polymyalgia rheumatica: age over 50, bilateral shoulder and hip girdle pain and stiffness, raised ESR or CRP, and rapid response to prednisolone 15 mg daily.

Sjogren's syndrome: dry eyes and mouth, anti-Ro and anti-La antibodies, positive Schirmer test, and an increased risk of B-cell lymphoma.

Septic arthritis: synovial white cell count usually above 50,000/microlitre; urgent aspiration and intravenous antibiotics are required.

Iron deficiency: low ferritin, microcytosis, raised total iron-binding capacity and low transferrin saturation; ferritin is an acute phase reactant, so a normal value does not exclude deficiency during inflammation.

Anaemia of chronic disease: low serum iron with low total iron-binding capacity and normal or raised ferritin.

Vitamin B12 deficiency: macrocytic anaemia with raised methylmalonic acid and homocysteine; folate deficiency raises homocysteine alone.

CML carries t(9;22) BCR-ABL1 and is treated with imatinib; acute promyelocytic leukaemia carries t(15;17) PML-RARA and is treated with all-trans retinoic acid.

Disseminated intravascular coagulation: prolonged PT and APTT, thrombocytopenia, low fibrinogen and raised D-dimers; treat the underlying cause with supportive blood products.

Thrombotic thrombocytopenic purpura: microangiopathic haemolytic anaemia, thrombocytopenia, neurological and renal features and fever with ADAMTS13 deficiency; treat with plasma exchange.

Heparin-induced thrombocytopenia: platelet count falls by more than 50% at 5-10 days with paradoxical thrombosis; stop heparin and start argatroban or fondaparinux.

Myeloma: CRAB features (hypercalcaemia, renal failure, anaemia, bone lesions), a paraprotein on electrophoresis and marrow plasma cells above 10%.

Malaria: ring forms on thick film; Plasmodium falciparum shows banana-shaped gametocytes; severe disease is treated with intravenous artesunate.

Typhoid fever: step-ladder fever, relative bradycardia, rose spots and hepatosplenomegaly; diagnose with blood culture and treat with ceftriaxone or azithromycin.

Dengue: thrombocytopenia with rising haematocrit indicates plasma leakage; avoid NSAIDs and aspirin because of bleeding risk.

HIV: a fourth-generation combined antigen-antibody assay is used for screening and HIV RNA for confirmation; antiretroviral therapy is started regardless of CD4 count.

Pneumocystis jirovecii pneumonia: CD4 count below 200 cells/microlitre, ground-glass infiltrates and raised LDH; treat and prophylax with co-trimoxazole.

Syphilis: treat with benzylpenicillin; the Jarisch-Herxheimer reaction of fever and rigors follows the first dose and is managed supportively.

Leptospirosis (Weil's disease): jaundice, acute kidney injury, haemorrhage and myocarditis after contact with contaminated water; treat with benzylpenicillin or doxycycline.

Streptococcus bovis bacteraemia or endocarditis warrants colonoscopy, because of the association with colorectal adenoma and carcinoma.

Zero-order kinetics occur with phenytoin, ethanol and high-dose salicylates; elimination is constant, so small dose increases cause disproportionate rises in plasma concentration.

CYP inducers include rifampicin, carbamazepine, phenytoin, phenobarbital and St John's wort; they lower concentrations of warfarin, oestrogens and many antiepileptics.

CYP3A4 inhibitors include macrolides other than azithromycin, azole antifungals, verapamil, diltiazem, ritonavir and grapefruit juice.

Lithium has a therapeutic range of 0.6-1.0 mmol/L; toxicity risk rises with dehydration, NSAIDs, thiazides and ACE inhibitors, and levels are taken 12 hours after the dose.

Digoxin toxicity causes nausea, yellow-green visual disturbance and arrhythmias, is precipitated by hypokalaemia and renal impairment, and is treated with digoxin-specific antibody fragments.

Warfarin inhibits vitamin K epoxide reductase and is monitored by INR; reverse with vitamin K plus prothrombin complex concentrate in major bleeding.

Steady state is reached after four to five half-lives; loading dose = (volume of distribution x target concentration) / bioavailability.

Aminoglycosides and vancomycin need therapeutic drug monitoring because of their narrow therapeutic index and nephrotoxicity.

Psoriasis: well-demarcated erythematous plaques with silvery scale on extensor surfaces, Auspitz sign and Koebner phenomenon; first-line treatment is a topical corticosteroid with a vitamin D analogue.

Pemphigus vulgaris: flaccid intraepidermal blisters, positive Nikolsky sign and IgG against desmoglein 1 and 3; treat with systemic corticosteroids plus a steroid-sparing agent.

Bullous pemphigoid: tense subepidermal blisters in older adults with linear IgG and C3 at the basement membrane and antibodies to BP180 and BP230.

Dermatitis herpetiformis: itchy vesicles on extensor surfaces with granular IgA in the dermal papillae, associated with coeliac disease, treated with dapsone and a gluten-free diet.

Melanoma: assessed by the ABCDE criteria, with Breslow thickness the strongest prognostic factor and the determinant of excision margins and sentinel node biopsy.

Stevens-Johnson syndrome involves 10-30% body surface area and toxic epidermal necrolysis more than 30%; both are usually drug-induced, whereas erythema multiforme usually follows herpes simplex.

Porphyria cutanea tarda: fragile skin and blisters on sun-exposed areas with uroporphyrinuria, associated with alcohol, hepatitis C and haemochromatosis.

Lichen planus: pruritic, purple, polygonal planar papules with Wickham striae, affecting wrists, ankles and oral mucosa.

Delirium: acute onset with fluctuating course and inattention, screened with the 4AT; the hypoactive subtype is frequently mistaken for depression or dementia.

Falls in older adults require multifactorial assessment including postural blood pressure, ECG, vision, gait and balance, continence and a full medication review.

High anticholinergic burden and polypharmacy worsen cognition and cause urinary retention, constipation and falls; STOPP/START and Beers criteria guide deprescribing.

Dementia subtypes: Alzheimer's (early memory loss), vascular (stepwise decline with focal signs), Lewy body (fluctuations, visual hallucinations, parkinsonism, neuroleptic sensitivity), frontotemporal (behavioural or language variants).

Frailty is identified by the Fried phenotype (weight loss, exhaustion, low activity, slow gait, weakness) or by a cumulative deficit index.

Syncope red flags: exertional syncope, family history of sudden cardiac death, abnormal ECG or structural heart disease; these require admission and cardiac assessment.

Pressure ulcers are risk-assessed with the Braden scale and staged 1-4; prevention uses repositioning, pressure-relieving surfaces and nutritional support.

Hypothermia below 35 degrees Celsius: look for sepsis, myxoedema, hypoglycaemia, stroke and drug toxicity; rewarm gradually while treating the underlying cause.