Pathology EMQ: See the comment at the bottom of this page.

 

Your Name:

Your Identifier:

Theme: Acid-Base Balance

 

OPTION LIST

Choose the appropriate diagnosis

 

A

Alpha1 anti-trypsin deficiency

I

Intestinal fistula

B

Aspirin overdose

J

Metformin side-effect

C

Asthma

K

Opioid overdose

D

COPD

L

Panic Attack

E

DKA

M

Pyloric stenosis

F

Hypokalaemia

N

Renal Tubular Acidosis

G

Inappropriate oxygen

O

Stimulation of resp centre

H

Ingestion of bicarbonate

P

 

 

For each scenario below, choose the most appropriate answer from the list above. Each option may be used once, more than once or not at all. 

1)    A fat 56-year old diabetic gentleman turns up at A&E having been discharged following a Myocardial infarction ten days ago. He says that after recovering in hospital, he was sent home and has been steadily feeling weaker. He has been sleepy, light-headed and short of breath and complains of occasional crampy abdominal pains. He is concerned he is having another heart attack.

 

You perform an ABG and U+E blood test. The results are:

pH – 7.1, PO2 – 15kPa, PCO2 – 3kPa, HCO3- - 6.8mmol/L, Na – 140mmol/L, K - 4.7mmol/L, Urea – 4mmol/L, Glucose – 4mmol/L, Measured Osmolality – 318mOsm/kg

 

2)    A 28-year old banker is brought in by his intoxicated banker friends. He is unconscious and barely seems to be breathing. His friends disappear as soon as they see you arrive and give you no collateral history.

 

pH – 7.1, PO2 – 6kPa, PCO2 – 9kPa, HCO3- - 21mmol/L, Na – 138mmol/L, K – 3.9mmol/L, Urea – 6mmol/L, Glucose – 2.5mmol/L, Measured Osmolality – 295mOsm/kg

 

3)    A 64-year old gentleman who was a heavy smoker and still continues to smoke has returned to the ward for the third time this year. He was very SOB on admission and was put on 31% Oxygen, whereupon he became less distressed. Whilst updating drug charts, one of the nurses runs up to you, panicked as this gentleman seems to be turning blue and is starting to lose consciousness.

 

pH – 7.3,  PO2 – 12kPa, PCO2 – 10.5kPa, HCO3- - 38mmol/L, Na – 144mmol/L, K – 4.1mmol/L, Urea – 7mmol/L, Glucose – 4mmol/L, Measured Osmolality – 307mOsm/kg

 

4)    A worried mother and father bring in their 2 month old daughter who has been vomiting increasingly frequently and won’t stop crying.

 

pH – 7.65, PO2 – 12kPa, PCO2 – 5kPa, HCO3- - 40mmol/L, Na – 144mmol/L, K – 2.9mmol/L, Cl- - 80mmol/L

 

5)    A 27 year old female medical student comes in extremely short of breath the day before her final exams. She is taking many puffs from her blue inhaler, which seem to have no effect. In between breaths you manage to learn that she does not normally suffer from severe asthma.

 

pH – 7.65, PO2 – 16kPa, PCO2 – 2.9kPa, HCO3- - 23mmol/L, Na – 140mmol/L, K – 4.0mmol/L, Urea – 6mmol/L, Glucose – 3mmol/L, Measured Osmolality – 298mOsm/kg

 

 

 

ANSWERS

1.            J

2.            K

3.            G

4.            M

5.            L

 

It is important to realise that only the pH and CO2 are measured, and the bicarbonate calculated from the Henderson Hasselbach equation. You can’t just guess what the bicarbonate is going to me. Karim has edited this question using the equation to make sure that the numbers are possible. For example the following is impossible:

 

pH – 7.1, PO2 – 15kPa, PCO2 – 3kPa, HCO3- - 38mmol/L.

 

Thus if you write such a question, please put in the pH and pCO2, and then CALCULATE the bicarbonate. In the above example, it will be 6.8 mmol/l.