PGIM MD Medicine cheat sheet

Acute kidney injury staging (KDIGO): stage 1 creatinine rise ≥26.5 µmol/L or 1.5-1.9x baseline; stage 2 2.0-2.9x; stage 3 ≥3x, ≥353.6 µmol/L, or initiation of renal replacement therapy.

Nephrotic syndrome: proteinuria >3.5 g/day, albumin <30 g/L, oedema, and hyperlipidaemia; nephritic syndrome features haematuria with red cell casts and hypertension.

Stroke thrombolysis window: intravenous alteplase or tenecteplase generally within 4.5 h of symptom onset; mechanical thrombectomy up to 24 h in selected patients with salvageable tissue.

Cirrhosis complications: ascites managed with spironolactone plus furosemide and sodium restriction; spontaneous bacterial peritonitis diagnosed by ascitic neutrophil count ≥250 cells/mm³.

Rheumatology serology: anti-CCP is more specific than rheumatoid factor for rheumatoid arthritis; anti-dsDNA and anti-Smith are specific for systemic lupus erythematosus; ANCA patterns guide vasculitis classification.

Asthma versus COPD: asthma shows variable airflow limitation with reversibility (FEV1 improvement >12% and >200 mL after bronchodilator); COPD shows persistent post-bronchodilator obstruction.

Diabetic ketoacidosis management: isotonic saline resuscitation, intravenous insulin infusion, and potassium replacement once K+ <5.5 mmol/L; add dextrose when glucose falls below ~14 mmol/L.

Atrial fibrillation stroke risk: CHA2DS2-VASc score ≥2 in men or ≥3 in women generally warrants anticoagulation; DOACs preferred over warfarin in non-valvular AF.

Osmolality: calculated serum osmolality = 2×Na+ + glucose + urea (all mmol/L); measured minus calculated osmolality >10 mOsm/kg suggests an osmolar gap from toxins such as methanol or ethylene glycol.

Anion gap = Na+ − (Cl− + HCO3−), normal 8-12 mmol/L; raised gap with metabolic acidosis suggests ketoacidosis, lactic acidosis, renal failure, or toxins.

Arterial blood gas interpretation sequence: assess pH, then PaCO2 (respiratory), then HCO3− (metabolic), then check compensation and calculate the anion gap.

Winter's formula: expected PaCO2 = 1.5 × HCO3− + 8 ± 2; deviation indicates an additional respiratory acid-base disorder.

Corrected sodium in hyperglycaemia: add 2.4 mmol/L to measured Na+ for every 5.5 mmol/L glucose above 5.5 mmol/L (or use factor 0.3 × glucose excess).

Liver enzymes: ALT and AST reflect hepatocellular injury; alkaline phosphatase and GGT reflect cholestasis; an AST:ALT ratio >2 suggests alcoholic liver disease.

Cardiac troponin rises within 3-6 h of myocardial injury, peaks around 12-24 h, and remains elevated for 7-14 days; CK-MB normalises faster, aiding reinfarction detection.

Spirometry patterns: obstructive shows reduced FEV1/FVC; restrictive shows reduced FVC with preserved or raised FEV1/FVC ratio; confirm restriction with lung volumes.

Sepsis-3 definition: life-threatening organ dysfunction from dysregulated host response to infection, operationalised as a rise in SOFA score ≥2; qSOFA (respiratory rate ≥22, altered mentation, systolic BP ≤100) flags risk.

Septic shock: persistent hypotension requiring vasopressors to maintain MAP ≥65 mmHg plus lactate >2 mmol/L despite adequate fluid resuscitation.

Anaphylaxis: intramuscular adrenaline 0.5 mg (0.5 mL of 1:1000) into the anterolateral thigh for adults, repeated every 5 minutes as needed; antihistamines and steroids are adjuncts only.

Acute upper GI bleeding: pre-endoscopic Glasgow-Blatchford score identifies low-risk patients for outpatient management; variceal bleeding requires terlipressin plus prophylactic antibiotics and urgent endoscopy.

Acute severe asthma: give oxygen targeting SpO2 94-98%, repeated inhaled salbutamol with ipratropium, systemic corticosteroids, and consider magnesium sulphate; rising PaCO2 signals impending respiratory failure.

Diabetic ketoacidosis fluid: 0.9% sodium chloride 1 L over the first hour, then guided by haemodynamics; cerebral oedema is a feared complication in children and requires slow correction.

Post-cardiac-arrest care: targeted temperature management (32-37.5 °C) with avoidance of fever, maintenance of normoxia and normocapnia, and early coronary angiography if ST elevation.

Acute respiratory distress syndrome (Berlin definition): onset within 1 week, bilateral opacities, not fully explained by cardiac failure, with PaO2/FiO2 ≤300 mmHg on PEEP ≥5 cmH2O.

Hypertension diagnosis: clinic BP ≥140/90 mmHg confirmed by ambulatory (daytime ≥135/85) or home BP (≥135/85); white-coat effect defined by raised clinic but normal ambulatory readings.

Type 2 diabetes: HbA1c ≥6.5% (48 mmol/mol), fasting glucose ≥7.0 mmol/L, or 2-h OGTT ≥11.1 mmol/L; repeat to confirm unless classic symptoms with random glucose ≥11.1.

Acute coronary syndrome: serial high-sensitivity troponin at 0 and 1-3 h; a rise/fall pattern with at least one value above the 99th percentile URL defines myocardial infarction.

Community-acquired pneumonia severity: CURB-65 (confusion, urea >7 mmol/L, respiratory rate ≥30, BP <90/60, age ≥65); score ≥2 suggests inpatient care, ≥3 consider critical care.

Heart failure with reduced ejection fraction: four pillars are ACE inhibitor/ARB or ARNI, beta-blocker, mineralocorticoid receptor antagonist, and SGLT2 inhibitor; each reduces mortality.

Thyroid function: primary hypothyroidism shows high TSH with low free T4; subclinical disease shows high TSH with normal free T4; central hypothyroidism shows low free T4 with low or normal TSH.

Anaemia classification by mean corpuscular volume: microcytic (<80 fL) suggests iron deficiency, thalassaemia, or anaemia of chronic disease; macrocytic (>100 fL) suggests B12/folate deficiency, alcohol, or hypothyroidism.

Chronic obstructive pulmonary disease: post-bronchodilator FEV1/FVC <0.70 confirms persistent airflow obstruction; GOLD ABE grouping uses exacerbation history and symptom burden (mMRC, CAT).

Acute kidney injury staging (KDIGO): stage 1 creatinine rise ≥26.5 µmol/L or 1.5-1.9x baseline; stage 2 2.0-2.9x; stage 3 ≥3x, ≥353.6 µmol/L, or initiation of renal replacement therapy.

Nephrotic syndrome: proteinuria >3.5 g/day, albumin <30 g/L, oedema, and hyperlipidaemia; nephritic syndrome features haematuria with red cell casts and hypertension.

Stroke thrombolysis window: intravenous alteplase or tenecteplase generally within 4.5 h of symptom onset; mechanical thrombectomy up to 24 h in selected patients with salvageable tissue.

Cirrhosis complications: ascites managed with spironolactone plus furosemide and sodium restriction; spontaneous bacterial peritonitis diagnosed by ascitic neutrophil count ≥250 cells/mm³.

Rheumatology serology: anti-CCP is more specific than rheumatoid factor for rheumatoid arthritis; anti-dsDNA and anti-Smith are specific for systemic lupus erythematosus; ANCA patterns guide vasculitis classification.

Asthma versus COPD: asthma shows variable airflow limitation with reversibility (FEV1 improvement >12% and >200 mL after bronchodilator); COPD shows persistent post-bronchodilator obstruction.

Diabetic ketoacidosis management: isotonic saline resuscitation, intravenous insulin infusion, and potassium replacement once K+ <5.5 mmol/L; add dextrose when glucose falls below ~14 mmol/L.

Atrial fibrillation stroke risk: CHA2DS2-VASc score ≥2 in men or ≥3 in women generally warrants anticoagulation; DOACs preferred over warfarin in non-valvular AF.

Osmolality: calculated serum osmolality = 2×Na+ + glucose + urea (all mmol/L); measured minus calculated osmolality >10 mOsm/kg suggests an osmolar gap from toxins such as methanol or ethylene glycol.

Anion gap = Na+ − (Cl− + HCO3−), normal 8-12 mmol/L; raised gap with metabolic acidosis suggests ketoacidosis, lactic acidosis, renal failure, or toxins.

Arterial blood gas interpretation sequence: assess pH, then PaCO2 (respiratory), then HCO3− (metabolic), then check compensation and calculate the anion gap.

Winter's formula: expected PaCO2 = 1.5 × HCO3− + 8 ± 2; deviation indicates an additional respiratory acid-base disorder.

Corrected sodium in hyperglycaemia: add 2.4 mmol/L to measured Na+ for every 5.5 mmol/L glucose above 5.5 mmol/L (or use factor 0.3 × glucose excess).

Liver enzymes: ALT and AST reflect hepatocellular injury; alkaline phosphatase and GGT reflect cholestasis; an AST:ALT ratio >2 suggests alcoholic liver disease.

Cardiac troponin rises within 3-6 h of myocardial injury, peaks around 12-24 h, and remains elevated for 7-14 days; CK-MB normalises faster, aiding reinfarction detection.

Spirometry patterns: obstructive shows reduced FEV1/FVC; restrictive shows reduced FVC with preserved or raised FEV1/FVC ratio; confirm restriction with lung volumes.

Sepsis-3 definition: life-threatening organ dysfunction from dysregulated host response to infection, operationalised as a rise in SOFA score ≥2; qSOFA (respiratory rate ≥22, altered mentation, systolic BP ≤100) flags risk.

Septic shock: persistent hypotension requiring vasopressors to maintain MAP ≥65 mmHg plus lactate >2 mmol/L despite adequate fluid resuscitation.

Anaphylaxis: intramuscular adrenaline 0.5 mg (0.5 mL of 1:1000) into the anterolateral thigh for adults, repeated every 5 minutes as needed; antihistamines and steroids are adjuncts only.

Acute upper GI bleeding: pre-endoscopic Glasgow-Blatchford score identifies low-risk patients for outpatient management; variceal bleeding requires terlipressin plus prophylactic antibiotics and urgent endoscopy.

Acute severe asthma: give oxygen targeting SpO2 94-98%, repeated inhaled salbutamol with ipratropium, systemic corticosteroids, and consider magnesium sulphate; rising PaCO2 signals impending respiratory failure.

Diabetic ketoacidosis fluid: 0.9% sodium chloride 1 L over the first hour, then guided by haemodynamics; cerebral oedema is a feared complication in children and requires slow correction.

Post-cardiac-arrest care: targeted temperature management (32-37.5 °C) with avoidance of fever, maintenance of normoxia and normocapnia, and early coronary angiography if ST elevation.

Acute respiratory distress syndrome (Berlin definition): onset within 1 week, bilateral opacities, not fully explained by cardiac failure, with PaO2/FiO2 ≤300 mmHg on PEEP ≥5 cmH2O.

Hypertension diagnosis: clinic BP ≥140/90 mmHg confirmed by ambulatory (daytime ≥135/85) or home BP (≥135/85); white-coat effect defined by raised clinic but normal ambulatory readings.

Type 2 diabetes: HbA1c ≥6.5% (48 mmol/mol), fasting glucose ≥7.0 mmol/L, or 2-h OGTT ≥11.1 mmol/L; repeat to confirm unless classic symptoms with random glucose ≥11.1.

Acute coronary syndrome: serial high-sensitivity troponin at 0 and 1-3 h; a rise/fall pattern with at least one value above the 99th percentile URL defines myocardial infarction.

Community-acquired pneumonia severity: CURB-65 (confusion, urea >7 mmol/L, respiratory rate ≥30, BP <90/60, age ≥65); score ≥2 suggests inpatient care, ≥3 consider critical care.

Heart failure with reduced ejection fraction: four pillars are ACE inhibitor/ARB or ARNI, beta-blocker, mineralocorticoid receptor antagonist, and SGLT2 inhibitor; each reduces mortality.

Thyroid function: primary hypothyroidism shows high TSH with low free T4; subclinical disease shows high TSH with normal free T4; central hypothyroidism shows low free T4 with low or normal TSH.

Anaemia classification by mean corpuscular volume: microcytic (<80 fL) suggests iron deficiency, thalassaemia, or anaemia of chronic disease; macrocytic (>100 fL) suggests B12/folate deficiency, alcohol, or hypothyroidism.

Chronic obstructive pulmonary disease: post-bronchodilator FEV1/FVC <0.70 confirms persistent airflow obstruction; GOLD ABE grouping uses exacerbation history and symptom burden (mMRC, CAT).

Acute kidney injury staging (KDIGO): stage 1 creatinine rise ≥26.5 µmol/L or 1.5-1.9x baseline; stage 2 2.0-2.9x; stage 3 ≥3x, ≥353.6 µmol/L, or initiation of renal replacement therapy.

Nephrotic syndrome: proteinuria >3.5 g/day, albumin <30 g/L, oedema, and hyperlipidaemia; nephritic syndrome features haematuria with red cell casts and hypertension.

Stroke thrombolysis window: intravenous alteplase or tenecteplase generally within 4.5 h of symptom onset; mechanical thrombectomy up to 24 h in selected patients with salvageable tissue.

Cirrhosis complications: ascites managed with spironolactone plus furosemide and sodium restriction; spontaneous bacterial peritonitis diagnosed by ascitic neutrophil count ≥250 cells/mm³.

Rheumatology serology: anti-CCP is more specific than rheumatoid factor for rheumatoid arthritis; anti-dsDNA and anti-Smith are specific for systemic lupus erythematosus; ANCA patterns guide vasculitis classification.

Asthma versus COPD: asthma shows variable airflow limitation with reversibility (FEV1 improvement >12% and >200 mL after bronchodilator); COPD shows persistent post-bronchodilator obstruction.

Diabetic ketoacidosis management: isotonic saline resuscitation, intravenous insulin infusion, and potassium replacement once K+ <5.5 mmol/L; add dextrose when glucose falls below ~14 mmol/L.

Atrial fibrillation stroke risk: CHA2DS2-VASc score ≥2 in men or ≥3 in women generally warrants anticoagulation; DOACs preferred over warfarin in non-valvular AF.

Osmolality: calculated serum osmolality = 2×Na+ + glucose + urea (all mmol/L); measured minus calculated osmolality >10 mOsm/kg suggests an osmolar gap from toxins such as methanol or ethylene glycol.

Anion gap = Na+ − (Cl− + HCO3−), normal 8-12 mmol/L; raised gap with metabolic acidosis suggests ketoacidosis, lactic acidosis, renal failure, or toxins.

Arterial blood gas interpretation sequence: assess pH, then PaCO2 (respiratory), then HCO3− (metabolic), then check compensation and calculate the anion gap.

Winter's formula: expected PaCO2 = 1.5 × HCO3− + 8 ± 2; deviation indicates an additional respiratory acid-base disorder.

Corrected sodium in hyperglycaemia: add 2.4 mmol/L to measured Na+ for every 5.5 mmol/L glucose above 5.5 mmol/L (or use factor 0.3 × glucose excess).

Liver enzymes: ALT and AST reflect hepatocellular injury; alkaline phosphatase and GGT reflect cholestasis; an AST:ALT ratio >2 suggests alcoholic liver disease.

Cardiac troponin rises within 3-6 h of myocardial injury, peaks around 12-24 h, and remains elevated for 7-14 days; CK-MB normalises faster, aiding reinfarction detection.

Spirometry patterns: obstructive shows reduced FEV1/FVC; restrictive shows reduced FVC with preserved or raised FEV1/FVC ratio; confirm restriction with lung volumes.

Sepsis-3 definition: life-threatening organ dysfunction from dysregulated host response to infection, operationalised as a rise in SOFA score ≥2; qSOFA (respiratory rate ≥22, altered mentation, systolic BP ≤100) flags risk.

Septic shock: persistent hypotension requiring vasopressors to maintain MAP ≥65 mmHg plus lactate >2 mmol/L despite adequate fluid resuscitation.

Anaphylaxis: intramuscular adrenaline 0.5 mg (0.5 mL of 1:1000) into the anterolateral thigh for adults, repeated every 5 minutes as needed; antihistamines and steroids are adjuncts only.

Acute upper GI bleeding: pre-endoscopic Glasgow-Blatchford score identifies low-risk patients for outpatient management; variceal bleeding requires terlipressin plus prophylactic antibiotics and urgent endoscopy.

Acute severe asthma: give oxygen targeting SpO2 94-98%, repeated inhaled salbutamol with ipratropium, systemic corticosteroids, and consider magnesium sulphate; rising PaCO2 signals impending respiratory failure.

Diabetic ketoacidosis fluid: 0.9% sodium chloride 1 L over the first hour, then guided by haemodynamics; cerebral oedema is a feared complication in children and requires slow correction.

Post-cardiac-arrest care: targeted temperature management (32-37.5 °C) with avoidance of fever, maintenance of normoxia and normocapnia, and early coronary angiography if ST elevation.

Acute respiratory distress syndrome (Berlin definition): onset within 1 week, bilateral opacities, not fully explained by cardiac failure, with PaO2/FiO2 ≤300 mmHg on PEEP ≥5 cmH2O.

Hypertension diagnosis: clinic BP ≥140/90 mmHg confirmed by ambulatory (daytime ≥135/85) or home BP (≥135/85); white-coat effect defined by raised clinic but normal ambulatory readings.

Type 2 diabetes: HbA1c ≥6.5% (48 mmol/mol), fasting glucose ≥7.0 mmol/L, or 2-h OGTT ≥11.1 mmol/L; repeat to confirm unless classic symptoms with random glucose ≥11.1.

Acute coronary syndrome: serial high-sensitivity troponin at 0 and 1-3 h; a rise/fall pattern with at least one value above the 99th percentile URL defines myocardial infarction.

Community-acquired pneumonia severity: CURB-65 (confusion, urea >7 mmol/L, respiratory rate ≥30, BP <90/60, age ≥65); score ≥2 suggests inpatient care, ≥3 consider critical care.

Heart failure with reduced ejection fraction: four pillars are ACE inhibitor/ARB or ARNI, beta-blocker, mineralocorticoid receptor antagonist, and SGLT2 inhibitor; each reduces mortality.

Thyroid function: primary hypothyroidism shows high TSH with low free T4; subclinical disease shows high TSH with normal free T4; central hypothyroidism shows low free T4 with low or normal TSH.

Anaemia classification by mean corpuscular volume: microcytic (<80 fL) suggests iron deficiency, thalassaemia, or anaemia of chronic disease; macrocytic (>100 fL) suggests B12/folate deficiency, alcohol, or hypothyroidism.

Chronic obstructive pulmonary disease: post-bronchodilator FEV1/FVC <0.70 confirms persistent airflow obstruction; GOLD ABE grouping uses exacerbation history and symptom burden (mMRC, CAT).

Acute kidney injury staging (KDIGO): stage 1 creatinine rise ≥26.5 µmol/L or 1.5-1.9x baseline; stage 2 2.0-2.9x; stage 3 ≥3x, ≥353.6 µmol/L, or initiation of renal replacement therapy.

Nephrotic syndrome: proteinuria >3.5 g/day, albumin <30 g/L, oedema, and hyperlipidaemia; nephritic syndrome features haematuria with red cell casts and hypertension.

Stroke thrombolysis window: intravenous alteplase or tenecteplase generally within 4.5 h of symptom onset; mechanical thrombectomy up to 24 h in selected patients with salvageable tissue.

Cirrhosis complications: ascites managed with spironolactone plus furosemide and sodium restriction; spontaneous bacterial peritonitis diagnosed by ascitic neutrophil count ≥250 cells/mm³.

Rheumatology serology: anti-CCP is more specific than rheumatoid factor for rheumatoid arthritis; anti-dsDNA and anti-Smith are specific for systemic lupus erythematosus; ANCA patterns guide vasculitis classification.

Asthma versus COPD: asthma shows variable airflow limitation with reversibility (FEV1 improvement >12% and >200 mL after bronchodilator); COPD shows persistent post-bronchodilator obstruction.

Diabetic ketoacidosis management: isotonic saline resuscitation, intravenous insulin infusion, and potassium replacement once K+ <5.5 mmol/L; add dextrose when glucose falls below ~14 mmol/L.

Atrial fibrillation stroke risk: CHA2DS2-VASc score ≥2 in men or ≥3 in women generally warrants anticoagulation; DOACs preferred over warfarin in non-valvular AF.

Osmolality: calculated serum osmolality = 2×Na+ + glucose + urea (all mmol/L); measured minus calculated osmolality >10 mOsm/kg suggests an osmolar gap from toxins such as methanol or ethylene glycol.

Anion gap = Na+ − (Cl− + HCO3−), normal 8-12 mmol/L; raised gap with metabolic acidosis suggests ketoacidosis, lactic acidosis, renal failure, or toxins.

Arterial blood gas interpretation sequence: assess pH, then PaCO2 (respiratory), then HCO3− (metabolic), then check compensation and calculate the anion gap.

Winter's formula: expected PaCO2 = 1.5 × HCO3− + 8 ± 2; deviation indicates an additional respiratory acid-base disorder.

Corrected sodium in hyperglycaemia: add 2.4 mmol/L to measured Na+ for every 5.5 mmol/L glucose above 5.5 mmol/L (or use factor 0.3 × glucose excess).

Liver enzymes: ALT and AST reflect hepatocellular injury; alkaline phosphatase and GGT reflect cholestasis; an AST:ALT ratio >2 suggests alcoholic liver disease.

Cardiac troponin rises within 3-6 h of myocardial injury, peaks around 12-24 h, and remains elevated for 7-14 days; CK-MB normalises faster, aiding reinfarction detection.

Spirometry patterns: obstructive shows reduced FEV1/FVC; restrictive shows reduced FVC with preserved or raised FEV1/FVC ratio; confirm restriction with lung volumes.

Sepsis-3 definition: life-threatening organ dysfunction from dysregulated host response to infection, operationalised as a rise in SOFA score ≥2; qSOFA (respiratory rate ≥22, altered mentation, systolic BP ≤100) flags risk.

Septic shock: persistent hypotension requiring vasopressors to maintain MAP ≥65 mmHg plus lactate >2 mmol/L despite adequate fluid resuscitation.

Anaphylaxis: intramuscular adrenaline 0.5 mg (0.5 mL of 1:1000) into the anterolateral thigh for adults, repeated every 5 minutes as needed; antihistamines and steroids are adjuncts only.

Acute upper GI bleeding: pre-endoscopic Glasgow-Blatchford score identifies low-risk patients for outpatient management; variceal bleeding requires terlipressin plus prophylactic antibiotics and urgent endoscopy.

Acute severe asthma: give oxygen targeting SpO2 94-98%, repeated inhaled salbutamol with ipratropium, systemic corticosteroids, and consider magnesium sulphate; rising PaCO2 signals impending respiratory failure.

Diabetic ketoacidosis fluid: 0.9% sodium chloride 1 L over the first hour, then guided by haemodynamics; cerebral oedema is a feared complication in children and requires slow correction.

Post-cardiac-arrest care: targeted temperature management (32-37.5 °C) with avoidance of fever, maintenance of normoxia and normocapnia, and early coronary angiography if ST elevation.

Acute respiratory distress syndrome (Berlin definition): onset within 1 week, bilateral opacities, not fully explained by cardiac failure, with PaO2/FiO2 ≤300 mmHg on PEEP ≥5 cmH2O.

Hypertension diagnosis: clinic BP ≥140/90 mmHg confirmed by ambulatory (daytime ≥135/85) or home BP (≥135/85); white-coat effect defined by raised clinic but normal ambulatory readings.

Type 2 diabetes: HbA1c ≥6.5% (48 mmol/mol), fasting glucose ≥7.0 mmol/L, or 2-h OGTT ≥11.1 mmol/L; repeat to confirm unless classic symptoms with random glucose ≥11.1.

Acute coronary syndrome: serial high-sensitivity troponin at 0 and 1-3 h; a rise/fall pattern with at least one value above the 99th percentile URL defines myocardial infarction.

Community-acquired pneumonia severity: CURB-65 (confusion, urea >7 mmol/L, respiratory rate ≥30, BP <90/60, age ≥65); score ≥2 suggests inpatient care, ≥3 consider critical care.

Heart failure with reduced ejection fraction: four pillars are ACE inhibitor/ARB or ARNI, beta-blocker, mineralocorticoid receptor antagonist, and SGLT2 inhibitor; each reduces mortality.

Thyroid function: primary hypothyroidism shows high TSH with low free T4; subclinical disease shows high TSH with normal free T4; central hypothyroidism shows low free T4 with low or normal TSH.

Anaemia classification by mean corpuscular volume: microcytic (<80 fL) suggests iron deficiency, thalassaemia, or anaemia of chronic disease; macrocytic (>100 fL) suggests B12/folate deficiency, alcohol, or hypothyroidism.

Chronic obstructive pulmonary disease: post-bronchodilator FEV1/FVC <0.70 confirms persistent airflow obstruction; GOLD ABE grouping uses exacerbation history and symptom burden (mMRC, CAT).

Acute kidney injury staging (KDIGO): stage 1 creatinine rise ≥26.5 µmol/L or 1.5-1.9x baseline; stage 2 2.0-2.9x; stage 3 ≥3x, ≥353.6 µmol/L, or initiation of renal replacement therapy.

Nephrotic syndrome: proteinuria >3.5 g/day, albumin <30 g/L, oedema, and hyperlipidaemia; nephritic syndrome features haematuria with red cell casts and hypertension.

Stroke thrombolysis window: intravenous alteplase or tenecteplase generally within 4.5 h of symptom onset; mechanical thrombectomy up to 24 h in selected patients with salvageable tissue.

Cirrhosis complications: ascites managed with spironolactone plus furosemide and sodium restriction; spontaneous bacterial peritonitis diagnosed by ascitic neutrophil count ≥250 cells/mm³.

Rheumatology serology: anti-CCP is more specific than rheumatoid factor for rheumatoid arthritis; anti-dsDNA and anti-Smith are specific for systemic lupus erythematosus; ANCA patterns guide vasculitis classification.

Asthma versus COPD: asthma shows variable airflow limitation with reversibility (FEV1 improvement >12% and >200 mL after bronchodilator); COPD shows persistent post-bronchodilator obstruction.

Diabetic ketoacidosis management: isotonic saline resuscitation, intravenous insulin infusion, and potassium replacement once K+ <5.5 mmol/L; add dextrose when glucose falls below ~14 mmol/L.

Atrial fibrillation stroke risk: CHA2DS2-VASc score ≥2 in men or ≥3 in women generally warrants anticoagulation; DOACs preferred over warfarin in non-valvular AF.

Osmolality: calculated serum osmolality = 2×Na+ + glucose + urea (all mmol/L); measured minus calculated osmolality >10 mOsm/kg suggests an osmolar gap from toxins such as methanol or ethylene glycol.

Anion gap = Na+ − (Cl− + HCO3−), normal 8-12 mmol/L; raised gap with metabolic acidosis suggests ketoacidosis, lactic acidosis, renal failure, or toxins.

Arterial blood gas interpretation sequence: assess pH, then PaCO2 (respiratory), then HCO3− (metabolic), then check compensation and calculate the anion gap.

Winter's formula: expected PaCO2 = 1.5 × HCO3− + 8 ± 2; deviation indicates an additional respiratory acid-base disorder.

Corrected sodium in hyperglycaemia: add 2.4 mmol/L to measured Na+ for every 5.5 mmol/L glucose above 5.5 mmol/L (or use factor 0.3 × glucose excess).

Liver enzymes: ALT and AST reflect hepatocellular injury; alkaline phosphatase and GGT reflect cholestasis; an AST:ALT ratio >2 suggests alcoholic liver disease.

Cardiac troponin rises within 3-6 h of myocardial injury, peaks around 12-24 h, and remains elevated for 7-14 days; CK-MB normalises faster, aiding reinfarction detection.

Spirometry patterns: obstructive shows reduced FEV1/FVC; restrictive shows reduced FVC with preserved or raised FEV1/FVC ratio; confirm restriction with lung volumes.

Sepsis-3 definition: life-threatening organ dysfunction from dysregulated host response to infection, operationalised as a rise in SOFA score ≥2; qSOFA (respiratory rate ≥22, altered mentation, systolic BP ≤100) flags risk.

Septic shock: persistent hypotension requiring vasopressors to maintain MAP ≥65 mmHg plus lactate >2 mmol/L despite adequate fluid resuscitation.

Anaphylaxis: intramuscular adrenaline 0.5 mg (0.5 mL of 1:1000) into the anterolateral thigh for adults, repeated every 5 minutes as needed; antihistamines and steroids are adjuncts only.

Acute upper GI bleeding: pre-endoscopic Glasgow-Blatchford score identifies low-risk patients for outpatient management; variceal bleeding requires terlipressin plus prophylactic antibiotics and urgent endoscopy.

Acute severe asthma: give oxygen targeting SpO2 94-98%, repeated inhaled salbutamol with ipratropium, systemic corticosteroids, and consider magnesium sulphate; rising PaCO2 signals impending respiratory failure.

Diabetic ketoacidosis fluid: 0.9% sodium chloride 1 L over the first hour, then guided by haemodynamics; cerebral oedema is a feared complication in children and requires slow correction.

Post-cardiac-arrest care: targeted temperature management (32-37.5 °C) with avoidance of fever, maintenance of normoxia and normocapnia, and early coronary angiography if ST elevation.

Acute respiratory distress syndrome (Berlin definition): onset within 1 week, bilateral opacities, not fully explained by cardiac failure, with PaO2/FiO2 ≤300 mmHg on PEEP ≥5 cmH2O.