OSCE with answers

PMHJan 2012

Case 1

F/38, history of SchizophreniaDrank a bottle (60ml) of Red Flower OilRepeated vomiting, denied any tinnitusGCS 15, BP 159/90, P 83, Temp 37.2oCH’stix 6.3, SpO2 98% room air

•What is the main toxic component of Red Flower Oil? (0.5 mark)•What is the difference between the above component and acetylsalicylate? (0.5 mark)

Case 1F/38, history of SchizophreniaDrank a bottle (60ml) of Red Flower OilRepeated vomiting, denied any tinnitusGCS 15, BP 159/90, P 83, Temp 37.2oCH’stix 6.3, SpO2 98% room air

•What is the main toxic component of Red Flower Oil? (0.5 mark) Methylsalicylate•What is the difference between the above component and acetylsalicylate? (0.5 mark) Absorption is even more rapid

正紅花油 Red Flower Oil• Component according to the label– Methylsalicylate: 75% Methylsalicylate （冬青油）– Essential oil: 10% Cinnamon oil（桂葉油）– Hydrocarbons: 15% Camphor oil （白樟油）

• Amount of salicylate ingested per body weight – Assumed body weight = 50kg– 60ml x 75g/100ml ÷ 50kg = 45000 mg ÷ 50kg = 900 mg/kg < 150 mg/kg Negligible toxicity

300 mg/kg May produce Severe toxicity

> 500 mg/kg Potentially fatal

More Rapid absorptionCompared with Acetylsalicylate (Aspirin)More Rapid absorptionCompared with Acetylsalicylate (Aspirin)

CNS DepressionAspirationCNS DepressionAspiration CNS ToxicityCNS Toxicity

Case 1Blood gas and electrolytes result in A&E

• pH 7.5, HCO3 20 mmol/l

• pCO2 26mmHg, PO2 250 mmHg

• Na 146 mmol/l, K 3.2 mmol/l, Cl 104 mmol/l• Serum salicylate level = 6.19 mmol/l

•What are the acid-base disturbances? Why? (1.5 marks)•If the patient required intubation due to decreased consciousness and airway protection, what precaution about ventilation should be made? (0.5 mark)•What is the treatment for the current clinical condition? (0.5 marks)

Case 1Blood gas and electrolytes result in A&E

• pH 7.5, HCO3 20 mmol/l

• pCO2 26mmHg, PO2 250 mmHg

• Na 146 mmol/l, K 3.2 mmol/l, Cl 104 mmol/l• Serum salicylate level = 6.19 mmol/l

•What is the acid-base disturbance? Why? (1.5 marks)Triple acid base disturbancePredominately respiratory alkalosis, pH>7.45 & pCO2<40mmHg

- Stimulation of respiratory center by salicylateMetabolic acidosis: AG = 146-104-20=22- Block TCA cycle and Lactic acidosis, Acid metabolitesMetabolic alkalosis: ∆AG=22-12=10, ∆HCO3=24-20=4, ∆AG/∆HCO3=2.5, ∆Delta=10-4=6

- Vomiting and volume contraction•If the patient required intubation due to decreased consciousness, what precaution on ventilation should be made? (0.5 mark)

Maintaining hyperventilation•What would be the treatment option? (0.5 marks)

Correct hypokalemia and urine alkalization

Delta ratio = ∆AG / ∆HCO3Delta Gap: ∆Delta = ∆AG - ∆HCO3

Delta Ratio

Clinical Significance

<0.4 Hyperchloraemic normal anion gap acidosis

0.4-1 Consider combined high AG & normal AG acidosis BUT note that the ratio is often <1 in acidosis associated with renal failure

1-2 Usual for uncomplicated high-AG acidosisLactic acidosis: average value 1.6DKA more likely to have a ratio closer to 1 due to urine ketone loss (esp. if patient not dehydrated)

>2 Suggests a pre-existing elevated HCO3 level so consider:•a concurrent metabolic alkalosis, or•a pre-existing compensated respiratory acidosis

Triple Acid Base DisorderMetabolic acidosis + Metabolic alkalosis + Respiratory alkalosis

Without compensation in ventilation

• Triple acid-base disorder– Metabolic acidosis + Metabolic alkalosis + Respiratory

alkalosis

Lack of hyperventilatione.g. Intubation without hyperventilationCNS suppression

RESPIRATORY ACIDOSIS

DEATHMaintain adequate

hyperventilation Monitor acid-base balance

17 Oct

16 Oct

18 Oct

Therapeutic Range 1.1-2.2 mmol/lTherapeutic Range 1.1-2.2 mmol/l

Consider Urine alkalization 2.9-7.3 mmol/lConsider Urine alkalization 2.9-7.3 mmol/l

Consider Haemodialysis ≥ 7.3 mmol/lConsider Haemodialysis ≥ 7.3 mmol/l

Repeated serum salicylate level was measured. •What is the half-life of salicylate in therapeutic dose? (0.5 mark)•Why was the serum salicylate level of this patient behaved differently? (1 mark)

Repeated serum salicylate level was measured. •What is the half-life of salicylate in therapeutic dose? (0.5 mark)

2-4 hours•Why was the serum salicylate level of this patient behaved differently? (1 mark)

Michaelis-Menten kinetics, enzyme are saturated in overdose condition causing zero-order elimination

Zero-order kinetic

1st order kinetic

Case 2F/78, history of DM, HT, old right hip fracture with OT Right side abdominal pain for 1 weekPreceded by on and off right hip pain for recent 1 monthNo dysuria, or urinary frequency reportedNo shifting pain, nausea, vomiting or diarrhea

BP 90/40 P 130, Temp 39.2oC, H’stix 13.2

•What are the abnormalities in AXR? (2 marks)•What is the diagnosis? (1 mark)•What would be the predisposing factor presented in this case? (1 mark)•Would you recommend Xigris® (Drotrecogin alfa)? Yes/No - Why? (1 mark)

Case 2F/78, history of DM, HT, old right hip fracture with OT Right side abdominal pain for 1 weekNo dysuria, or urinary frequency reportedNo shifting pain, nausea or vomitingOn and off right hip pain for recent 1 month

BP 90/40 P 130, Temp 39.2oC, H’stix 16.2

•What are the abnormalities in AXR? (2 marks)Abnormal gas over RUQ, Right hip joint replacementDisplacement of right kidney shadow and bowel shadow, Scoliosis

•What is the diagnosis? (1 mark)Right retroperitoneal abscess

•What would be the predisposing factor presented in this case? (1 mark)Right hip joint replacement

•Would you recommend Xigris® (Drotrecogin alfa)? Yes/No - Why? (1 mark)

No, Xigris was recently withdrawn from market due to lack of efficacy

Abnormal gas collection

Abnormal gas collection Displaced right kidney

Abnormal gas collection Displaced right kidney Scoliosis Displaced bowel shadowDisplaced bowel shadow

Abnormal gas collection Displaced right kidney Scoliosis Displaced bowel shadowDisplaced bowel shadow

Right hip joint replacement

Case 3M/50, private car driver with good past healthSevere head injury with right chest wall injuryCXR – Right side pneumothorax, multiple ribs fractureIntubated and right intercostal drain inserted, swinging and bubbling were present, post-insertion CXR takenNoticed desaturation few minutes after insertion

•What are the X-ray findings? (3 marks)•What is the most likely cause of deterioration? (1 mark)•What is the treatment option for the above deterioration? (1 mark)

Case 3M/50, private car driver with good past healthSevere head injury with right chest wall CXR – Right side pneumothorax with multiple ribs fracture

Intubated and right intercostal drain inserted, swinging and bubbling were present, post-insertion CXR takenNoticed desaturation few minutes after insertion

•What are the X-ray abnormalities? (3 marks)Multiple ribs fracture with flail chest, right lung intubation and hyperinflation and underlying lung contusion, mediastinal shift with tracheal deviation, subcutaneous emphysema, Position of right intercostal drain is too low

•What is the most likely cause of deterioration? (1 mark)Right lung intubation

•What is the treatment option? (1 mark)Repositioning of endotracheal tube

ET Tube

Right heart border

Chest drain position

Flailed Chest

Subcutaneous emphysemaSubcutaneous emphysema

Lung ContusionLung Contusion

Pressure gradient, Right shift to LeftPressure gradient, Right shift to Left

After 3 cm withdrawal of endotracheal tube

Case 4

F/30, no major medical chronic illness,Presented with abdominal pain, nausea, vomiting and diarrhea for 7 daysAbdominal distension and headache were reportedBP 135/86 P 110, Temp 37.5oCPregnancy test negativeBedside ultrasonography was performed

•What are the abnormalities? (1.5 mark)•What is your diagnosis? (0.5 mark)

Case 4• F/30• Presented with abdominal pain, nausea, vomiting and diarrhea for

2 days• Mild abdominal distension and headache were reported• BP 135/86 P 110, Temp 37.5oC• Pregnancy test negative• Bedside ultrasonography was performed

• What are the abnormalities? (1.5 mark)Fluid in Morrison’s pouch and pouch of DouglasMultiple enlarge ovarian follicles

• What is your diagnosis? (0.5 mark)Ovarian hyper-stimulation syndrome (OHSS)

Fluid in Morrison’s Pouch

Fluid in POD

Multiple cysts in Ovary

Patient becomes drowsy and developed seizure during observation, CT brain was performed.•What abnormalities has been shown in CT Brain? (1 mark)•What other signs you would like to look for in Contrast film? (1 mark)•What is the diagnosis? (0.5 mark)•Is there any association with the patient’s presenting problem? (0.5 mark)

Patient becomes drowsy and developed seizure during observation. CT brain was performed.•What abnormalities has been shown in CT Brain? (1 mark)

Cord sign – Prominent engorged superior sagital and right transverse sinus•What other signs you would like to look for in Contrast film? (1 mark)

Empty delta sign, filling defects in cerebral sinus/vein•What is the diagnosis? (0.5 mark)

Cerebral venous thrombosis•Is there any association with the patient’s presenting problem? (0.5 mark)

Hypercoagulative status in OHSS

`̀

Right Transverse Sinus

Filling defect in Right transverse sinus

Filling defect in Sagital sinus

Empty delta Sign

Case 5M/70, History of HT, IHD, presented with dizzinessNot associated with chest pain, No LOC reported

BP 82/46 P 43, Temp 36.8oC, H’stix 5.3, ECG was done

•What are the ECG findings? (2 mark)

Due to persistent symptoms and medical treatment has been tried, but failed

•What would be the treatment option in A&E? (0.5 mark)•What medications you would like to use for better tolerance of the above treatment? (0.5 mark)•List 4 causes of failure for the above treatment (2 marks)

Case 5M/70, History of HT, IHD, Presented with dizzinessNot associated with chest pain, No LOC reported

BP 82/46 P 43, Temp 36.8oC, H’stix 5.3, ECG was done•What are the ECG findings? (2 mark)

AV dissociation – SA node fires at 85 b.p.m, Junction rhythm at 43 b.p.m.Complete heart blockLeft axis deviation

Due to persistent symptoms and medical treatment has been tried, but failed

•What would be the treatment option in A&E? (0.5 mark)Transcutaneous pacing

•What medications you would like to use for better tolerance of the above treatment? (0.5 mark)Midazolam and Fentanyl

•List 4 causes of failure for the above treatment (2 marks)Incorrect placement of pad, Big body build, Pericardial effusion, Hyperinflation of chest or pleural effusion

P waves

QRS Complex

END of OSCE

Thank you!