Diabetes Cases Flashcards
What characterises metabolic acidosis.
Low pH.
Low pCO2.
What characterises respiratory alkalosis.
High pH.
Low pCO2.
What characterises metabolic alkalosis.
High pH.
High pCO2.
What characterises respiratory acidosis.
Low pH.
High pCO2.
16 year old unconscious. Acutely unwell a few days ago.
Vomiting, breathless.
pH 6.85 pCO2 2.3kPa (4-5) pO2 15kPa Na 145 K 5 U 10 Glucose 25
What is the acid-base abnormality?
Why is he unconscious?
What is the osmolality?
What is the anion gap?
Metabolic acidosis.
He is unconscious because the brain enzymes cannot function at a very acid pH.
Osmolality = 335.
Anion gap = 50mM (suggests excess ketones)
How do you calculate the osmolality?
2(Na + K) + U + Glucose
How do you calculate the anion gap?
Na + K - Cl - bicarbonate
What is the normal anion gap?
18mM
A 19 year old known to have T1DM for several years presents unconscious.
pH 7.65 pCO2 2.8kPa Bicarbonate 24mM (normal) pO2 15kPa Na 140 K 4 Cl 100 Glucose 1.3
What is the acid-base abnormality?
What is the anion gap?
What is the diagnosis?
Respiratory alkalosis.
Anion gap = 20 (normal)
Diagnosis: anxiety caused by hypoglycaemia.
A 60 year old man presents unconscious to casualty, with a history of polyuria and polydipsia.
Na 160 K 6 U 50 pH 7.3 Glucose 60
What is the osmolality?
Why is he unconscious?
Osmolality = 442
He is unconscious because the brain is very dehydrated.
59 year old man known to have T2DM on a good diet and metformin presents to casualty unconscious.
Urine is negative for ketones.
Na 140 K 4 U 4 pH 7.10 Glucose 4 pCO2 1.3kPa Cl 90 Bicarbonate 4
What is the osmolality?
What is the anion gap?
What is the acid-base disturbance?
Why is he unconscious?
Osmolality: 296
Anion gap: 50
Acid-base abnormality: metabolic acidosis.
Why is he unconscious: There are an excess of anions which are not ketones. Other causes of this include methanol. ethanol, lactate and metformin overdose.
Metformin overdose can cause lactic acidosis.
The brain cannot function in such an acidic pH.
What can metformin overdose cause?
Lactic acidosis.
What is the definition of T2DM?
Fasting glucose >7mM
What is a glucose tolerance test?
Gives 75g of glucose at time 0 and measure at 2 hours.
What is the results of a GTT in T2DM?
Plasma glucose > 11.1mM at 2 hours.
