OSCE Data interpretation stations Dr Cathy Armstrong Consultant

OSCE Data interpretation stations Dr Cathy Armstrong Consultant Anaesthetist Dec 2014 www. cmft. nhs. uk/undergrad

Objectives • The stations – Format – Tips • Blood tests – Patterns to look for • examples www. cmft. nhs. uk/undergrad

Format • Instructions – Brief background – Study data – ‘after 5 minutes the examiner will ask you some questions on diagnosis & initial management’ www. cmft. nhs. uk/undergrad

Format • Data – Blood tests – ECG – CXR – Observations www. cmft. nhs. uk/undergrad

Format • Questions from examiner – Structured / standardised • ‘what do the blood tests show? ’ • ‘what does the CXR show? ’ • What is your most likely diagnosis? What is your top differential? • What will your initial management be? www. cmft. nhs. uk/undergrad

Tips • Use your thinking time wisely • Use succinct language & be confident – Likely to be some normal investigations also • Show reasoning behind your thoughts • Flag up potential dangers www. cmft. nhs. uk/undergrad

Tips • Differential diagnosis – Start with your top & why • Initial management – Might include oxygen / fluids / nebulisers – Remember management packages – e. g septic 6 – Further detailed history – Other definitive investigations – e. g. echo, CT – Don’t forget SENIOR HELP / INPUT www. cmft. nhs. uk/undergrad

Investigations www. cmft. nhs. uk/undergrad

Full Blood Count • Hb – Males 135 – 180 g/l – Females 115 – 160 g/l • WCC – 4. 0 – 11 x 109/l • Platelets – 150 – 400 x 109/l www. cmft. nhs. uk/undergrad

Anaemia classification by MCV – mean cell volume (76 – 96 fl) • Normal MCV (Normocytic) – Acute blood loss – Anaemia of chronic disease • Low MCV (microcytic) – Iron deficiency – Thalassaemia • High MCV (Macrocytic) – B 12 or folate deficiency www. cmft. nhs. uk/undergrad

High wcc - neutrophilia • • Raised WCC most commonly due to neutrophilia Neutrophils account for 40 – 75% of WBC recognise & ingest foreign particles & microorganisms Causes of neutrophilia – Infection – – – Trauma Infarction Inflammation Malignancy Myeloproliferative disease Physiological (exercise & pregnancy) www. cmft. nhs. uk/undergrad

Low wcc - neutropenia § Most commonly caused by neutropenia § Causes of neutropenia § Infection § § Drugs Autoimmune Alcohol congenital www. cmft. nhs. uk/undergrad

Thrombocytosis • Reactive – – – Chronic inflammatory disorders Malignant disease Post-haemorrhage Post-splenectomy Haemolytic anaemias • Malignant – Essential thrombocythaemia – Polycythaemia rubra vera – myelofibrosis www. cmft. nhs. uk/undergrad

Thrombocytopenia • Marrow disorders – Hypoplasia – idiopathic, drug-induced – Infiltration • Leukaemia, Myeloma, Carcinoma, Myelofibrosis – B 12 / folated deficiency • Increased consumption of platelets – DIC, ITP, viral infections, bacterial infections • Hypersplenism – Lymphoma, liver disease www. cmft. nhs. uk/undergrad

Urea & electrolytes • • Na K Ur Cr 135 -145 mmol/l 3. 5 – 5. 5 mmol/l 2. 5 – 6. 7 mmol/l 70 – 150 mmol/l www. cmft. nhs. uk/undergrad

Hyperkalaemia • • • Mild Mod Severe 5. 5 - 6. 0 mmol/l 6. 1 – 7. 0 mmol/l > 7. 0 mmol/l • Causes – ↑ intake • Food ingestion / supplements • Rapid blood transfusion – Intercompartmental shifts • Trauma / crush injuries • Burns • Acidosis – Decreased excretion • Acute / chronic renal failure • Adrenocortical insufficiency (e. g. Addisons disease) – Medications www. cmft. nhs. uk/undergrad • Potassium sparing diuretics, digoxin

Hyperkalaemia § ECG changes § § § § Peaked T waves Prolonged PR interval Widened QRS Loss of P wave Loss of R wave amplitude Sine wave pattern Asystole § Management of mod / severe § § § Treat underlying cause Calcium gluconate Insulin dextrose infusion Nebulised salbutamol dialysis www. cmft. nhs. uk/undergrad

Hypokalaemia • • • Mild Mod Severe 3. 0 – 3. 5 mmol/l 2. 5 – 3. 0 mmol/l < 2. 5 mmol/l • Causes – ↓ intake • Iatrogenic (no K in IV fluids) • Malnutrition – Renal losses • Renal tubular acidosis • Hyperaldosteronism (Conn’s syndrome) – GI losses • Diarrhoea, vomiting – Intercompartmental shifts • insulin • Alkalosis – Medications • Diuretics, β 2 agonists www. cmft. nhs. uk/undergrad

www. cmft. nhs. uk/undergrad

Hypernatraemia • Usually due to water loss in excess of sodium loss • Causes include: – Iatrogenic (too much IV N saline) – Diabetes Insipidus – Primary aldosteronism (Conn’s Syndrome) www. cmft. nhs. uk/undergrad

Diseases with electrolyte patterns • Addisons disease (Primary adrenocortical insufficiency) – Na K Ca • Cushings syndrome (excess plasma cortisol) – Na K Ca • Conn’s Syndrome (hyperaldosteronism) – Na K www. cmft. nhs. uk/undergrad

Diseases with electrolyte patterns • Addisons disease (Primary adrenocortical insufficiency) – Na ↓ K↑ Ca ↑ • Cushings syndrome (excess plasma cortisol) – Na ↑ K↓ Ca ↓ • Conn’s Syndrome (hyperaldosteronism) – Na ↑ ↔ K↓ www. cmft. nhs. uk/undergrad

Raised Urea & creatinine • Both raised in renal failure • Alternative causes of a raised urea with relatively normal Cr – Dehydration – GI haemhorrhage – High protein diet www. cmft. nhs. uk/undergrad

Deciphering between acute & chronic renal failure using blood results § Chronic renal failure § Anaemia of chronic disease § Low calcium § High phosphate www. cmft. nhs. uk/undergrad

Liver Function tests Non-specific Bilirubin AST (Aspartate transaminase) ALP (Alkaline phophatase) γ – GT Specific ALT (Alanine aminotransferase) (Gamma –glutamyl transpeptidase) Albumin www. cmft. nhs. uk/undergrad

LFT patterns • Hepatocellular Damage – Large ↑ in ALT with small ↑ in ALP • Biliary obstruction – Small ↑ ALT with large ↑ in ALP & γ -GT www. cmft. nhs. uk/undergrad

Areas not covered • Clotting studies – Anticoagulant monitoring • CRP • Blood cultures • Specialist tests – E. g – vasculitis screens / immunology www. cmft. nhs. uk/undergrad

Normal ABG Values p. H 7. 35 - 7. 45 Pa. O 2 10 -12 k. Pa IN AIR Pa. CO 2 4. 5 - 6. 0 k. Pa HCO 3 22 – 26 mmol/l Base Excess -2 - +2 mmol/l Many modern gas machines also measure K+ Na+ Cl- Sa. O 2 Hb COHb Met. Hb Lactate www. cmft. nhs. uk/undergrad

Expected PO 2 on oxygen % oxygen – 10 www. cmft. nhs. uk/undergrad

Examples www. cmft. nhs. uk/undergrad

Ryan • Ryan is a 17 year old male. He has presented to A&E with a 2 month history of general malaise. Over the past few days he has been vomiting with stomach cramps. • BP 110/70, Apyrexial, RR 39 • Review the investigations provided. You will then be asked questions on diagnosis and initial management. www. cmft. nhs. uk/undergrad

Ryan www. cmft. nhs. uk/undergrad

Ryan • • • Hb 12. 9 (9. 0 – 13. 0) Wcc 7. 0 (4. 0 – 11. 0) Plt 395 (150 -400) • • Na 139 (135 -145) K 4. 5 (3. 5 -5. 5) Ur 15. 0 (3. 3 -6. 6) Cr 140 (80 -120) • Blood glucose 35 mmol/l • ABG on air • • • p. H 7. 12 (7. 35 -7. 45) PCo 2 3. 0 (4. 5 -6. 0) PO 2 11. 0 (10 -12 in air) HCO 3 17 (22 -26) BE -23 (-2 - +2) www. cmft. nhs. uk/undergrad

Ryan www. cmft. nhs. uk/undergrad

Jack • Jack is a 77 year old male. He has presented to A&E with a 2 day history of abdominal pain and vomiting. • BP 90/45, T 38. 5. RR 30 • Examination of the abdomen reveals a hard abdomen with generalised tenderness and guarding • Review the investigations provided. You will then be asked questions on diagnosis and initial management. www. cmft. nhs. uk/undergrad

Jack • • • Hb 9. 0 (9. 0 – 13. 0) Wcc 22. 3 (4. 0 – 11. 0) Plt 170 (150 -400) • • Na 139 (135 -145) K 4. 5 (3. 5 -5. 5) Ur 10. 0 (3. 3 -6. 6) Cr 130 (80 -120) • ABG on air • • • p. H 7. 22 (7. 35 -7. 45) PCo 2 6. 1 (4. 5 -6. 0) PO 2 7. 5 (10 -12 in air) HCO 3 18 (22 -26) BE -10 (-2 - +2) www. cmft. nhs. uk/undergrad

Jack www. cmft. nhs. uk/undergrad

Jack www. cmft. nhs. uk/undergrad

Dorothy • Dorothy is a 82 year old female. She has presented to A&E with a 5 day history of productive cough with green sputum and worsening shortness of breath. • BP 93/50, T 38. 5. RR 32 • Review the investigations provided. You will then be asked questions on diagnosis and initial management. www. cmft. nhs. uk/undergrad

Dorothy • • • Hb 11. 0 (9. 0 – 13. 0) Wcc 21. 0 (4. 0 – 11. 0) Plt 250 (150 -400) • • Na 139 (135 -145) K 4. 5 (3. 5 -5. 5) Ur 8. 0 (3. 3 -6. 6) Cr 90 (80 -120) • ABG on 60% oxygen • • • p. H 7. 35 (7. 35 -7. 45) PCo 2 4. 2 (4. 5 -6. 0) PO 2 13 (10 -12 in air) HCO 3 23 (22 -26) BE -3 (-2 - +2) www. cmft. nhs. uk/undergrad

Dorothy www. cmft. nhs. uk/undergrad

Dorothy www. cmft. nhs. uk/undergrad

CURB 65 • • Confusion Urea – 7. 0 or over RR 30 or over BP – Systolic 90 or less OR – Diastolic 60 or less • Age 65 or over www. cmft. nhs. uk/undergrad

Sepsis 6 • • • Oxygen Blood cultures IV antibiotics Lactate & FBC IV fluids Measure UO www. cmft. nhs. uk/undergrad

Tom • Tom is a 22 year old male. He has presented to A&E with shortness of breath and an audible wheeze • BP 135/90, T 36. 5. RR 38 • Review the investigations provided. You will then be asked questions on diagnosis and initial management. www. cmft. nhs. uk/undergrad

Tom • • Hb 11. 0 (9. 0 – 13. 0) Wcc 6. 0 (4. 0 – 11. 0) Plt 250 (150 -400) Na 139 (135 -145) K 4. 5 (3. 5 -5. 5) Ur 5. 9 (3. 3 -6. 6) Cr 80 (80 -120) • ABG on 15 L oxygen via non-rebreath mask • • • p. H 7. 32 (7. 35 -7. 45) PCo 2 5. 9 (4. 5 -6. 0) PO 2 9 (10 -12 in air) HCO 3 23 (22 -26) BE -3 (-2 - +2) www. cmft. nhs. uk/undergrad

Tom www. cmft. nhs. uk/undergrad

Tom www. cmft. nhs. uk/undergrad

summary § Read instructions carefully § Take time to look at data, formulate a differential diagnosis & initial management plan § Be confident in your approach § Remember senior input www. cmft. nhs. uk/undergrad

www. cmft. nhs. uk/undergrad