Diabetes Clinical cases CID please… Chemical Pathology: Y5 Karim Meeran.

Diabetes

Clinical casesCID please…

Chemical Pathology: Y5

Karim Meeran

H + HCO3 = CO2 + H2O

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40

60

80

100

120

0 1 2 3 4 5 6 7 8 9

respiratory acidosis

respiratory alkalosis

Metabolic acidosis

Metabolic alkalosis

+ -

pCO2

pH [H+]6.92

7.0

7.1

7.22

7.407.527.707.80

Draw this on your IPAD

Case 1:

•16 year old unconscious.•Acutely unwell a few days.•Vomiting•Breathless.

Case 1: data

•pH 6.85•PCO2 = 2.3 kPa (N 4-5)

•PO2 = 15 kPa

What is the acid/base abnormality?

A. Respiratory acidosisB. Metabolic acidosisC. Respiratory alkalosisD. Metabolic alkalosis

pH 6.85PCO2 = 2.3 kPa (N 4-5)PO2 = 15 kPa

What is the acid/base abnormality?

•Low pH = acidosis•ie: excess H+ ions

•HCO3- + H+ = CO2 + H20

•Low CO2 = low bicarbonate

What is the acid/base abnormality?

•Draw the following graph, which will always tell you the answer:

H + HCO3 = CO2 + H2O

20

40

60

80

100

120

0 1 2 3 4 5 6 7 8 9

respiratory acidosis

respiratory alkalosis

Metabolic acidosis

Metabolic alkalosis

+ -

pCO2

pH [H+]6.92

7.0

7.1

7.22

7.407.527.707.80

Type in your CID now

What is the acid/base abnormality?

•Low pH = acidosis

•Low CO2 = low bicarbonate

•Metabolic acidosis

Case 1: more data.

•Na: 145, K: 5.0, U 10, pH 6.85, Glucose 25.

•Why is he unconscious ?

•What is the osmolality ?

Case 1: more data.

•Na: 145, K: 5.0, U 10, pH 6.85, Glucose 25.

•Why is he unconscious ? Because brain enzymes cannot function at a very acid pH

•What is the osmolality ?

Case 1: osmolality : derivation*

•Na: 145, K: 5.0, U 10, pH 6.85, Glucose 25.

•Osmolality = charged molecules + uncharged =cations + anions + urea + glucose

•(Na, K) (Cl, HCO3)

•Since cations = anions, this can be reduced to:•Osmolality = 2(Na+K) + U + G

Also PO4, SO4, etc

Case 1: osmolality : derivation*

•Na: 145, K: 5.0, U 10, pH 6.85, Glucose 25.

•Osmolality = charged molecules + uncharged =cations + anions + urea + glucose

•(Na, K) (Cl, HCO3)

•Since cations = anions, this can be reduced to:•Osmolality = 2(Na+K) + U + G•What is the osmolality?

Also PO4, SO4, etc

Case 1: osmolality

•Na: 145, K: 5.0, U 10, Glucose 25.

Case 1: anion gap*

•Cations (Na/K) = Anions (Cl, Bicarb, others)•“Others” known as “anion gap”.

•Anion gap = Na + K – Cl – bicarb

Case 1: anion gap*

•Cations (Na/K) = Anions (Cl, Bicarb, others)•“Others” known as “anion gap”.

•Anion gap = Na + K – Cl – bicarb

Case 1: anion gap*

•Cations (Na/K) = Anions (Cl, Bicarb, others)•“Others” known as “anion gap”.

•Anion gap = Na + K – Cl – bicarb •Normal AG =140+4.0 – 102 – 24 = 18 mM

Case 1: anion gap*

•Anion gap = Na + K – Cl – bicarb •Normal AG =140+4.0 – 102 – 24 = 18 mM

•In this patient:

Case 1: anion gap*

•Anion gap = Na + K – Cl – bicarb •Normal AG =140+4.0 – 102 – 24 = 18 mM

•In this patient calculate the anion gap now:

•145 + 5.0 – 96 – 4.0

Case 1: anion gap*

•Anion gap = Na + K – Cl – bicarb •Normal AG =140+4.0 – 102 – 24 = 18 mM

•In this patient:

•145 + 5.0 – 96 - 4•= (high)•Suggests extra anions (Ketones)

Case 2:

•A 19 year old known to have type 1 diabetes for several years presents unconscious.

•Results: pH 7.65•PCO2 = 2.8 kPa•Bicarb = 24 mM (normal)•PO2 = 15 kPa

What is the acid-base abnormality ?

Case 2: What is the acid/base abnormality?

A. Respiratory acidosisB. Metabolic acidosisC. Respiratory alkalosisD. Metabolic alkalosis

pH 7.65PCO2 = 2.8 kPaBicarb = 24 mM (normal)PO2 = 15 kPa

What is the acid/base abnormality?

•High pH = alkalosis

•Low CO2 = respiratory

H + HCO3 = CO2 + H2O

20

40

60

80

100

120

0 1 2 3 4 5 6 7 8 9

respiratory acidosis

respiratory alkalosis

Metabolic acidosis

Metabolic alkalosis

+ -

pCO2

pH [H+]6.92

7.0

7.1

7.22

7.407.527.707.80

Primary hyperventilation

Slows down spontaneously

What is the acid/base abnormality?

•High pH = alkalosis

•Respiratory alkalosis

Further results:

•Na = 140, K=4.0, bicarb=24, Cl=100•Glucose 1.3 mM

•What is the anion gap?

•What is the diagnosis ?

Further results:

•Na = 140, K=4.0, bicarb=24, Cl=100•Glucose 1.3 mM

•What is the anion gap? (normal)

•What is the diagnosis ?

Further results:

•Na = 140, K=4.0, bicarb=24, Cl=100•Glucose 1.3 mM

•What is the anion gap? (normal)

•What is the diagnosis ? Anxiety caused by hypoglycaemia.

Case 3.•60 year old man presents unconscious to casualty, with a history of polyuria and polydipsia. Investigations reveal:

•Na: 160, K: 6.0, U 50, pH 7.30, Glucose 60.

•What is the osmolality ?

•Why is he unconscious ?

Case 3.•60 year old man presents unconscious to casualty, with a history of polyuria and polydipsia. Investigations reveal:

•Na: 160, K: 6.0, U 50, pH 7.30, Glucose 60.

•What is the osmolality : mosm/kg

•Why is he unconscious ?

Case 3.•60 year old man presents unconscious to casualty, with a history of polyuria and polydipsia. Investigations reveal:

•Na: 160, K: 6.0, U 50, pH 7.30, Glucose 60.

•What is the osmolality : mosm/kg

•Why is he unconscious : because the brain is VERY dehydrated.

Case 4.•59 year old man known to have type 2 diabetes, on a good diet and metformin presents to casualty unconscious:

•Urine is negative for ketones.

•Na: 140, K: 4.0, U 4.0, pH 7.10, Glucose 4.0•PCO2=1.3 kPa. Cl = 90. Bicarb = 4.0 mM

•What is the osmolality :•What is the anion gap:•What is the acid-base disturbance•Why is he unconscious :

Case 4.•59 year old man known to have type 2 diabetes, on a good diet and metformin presents to casualty unconscious:

•Urine is negative for ketones.

•Na: 140, K: 4.0, U 4.0, pH 7.10, Glucose 4.0•PCO2=1.3 kPa. Cl = 90. Bicarb = 4.0 mM

•What is the osmolality :•What is the anion gap:•What is the acid-base disturbance•Why is he unconscious :

Case 4.•What is the osmolality :

•Na: 140, K: 4.0, U 4.0, pH 7.10, Glucose 4.0•PCO2=1.3 kPa. Cl = 90. Bicarb = 4.0 mM

•Osmo=2(Na+K) + U + G

Case 4.

•What is the anion gap:

•Na: 140, K: 4.0, U 4, pH 7.10, Glucose 4.0•PCO2=1.3 kPa. Cl = 90. Bicarb = 4.0 mM

•Urine is negative for ketones.

•Anion Gap = (Na+K) - bic - chloride•

Case 4.

•What is the anion gap:

•Na: 140, K: 4.0, U 4, pH 7.10, Glucose 4.0•PCO2=1.3 kPa. Cl = 90. Bicarb = 4.0 mM

•Urine is negative for ketones.

•Anion Gap = (Na+K) - bic - chloride•

Case 4.

•What is the anion gap:

•Na: 140, K: 4.0, U 4, pH 7.10, Glucose 4.0•PCO2=1.3 kPa. Cl = 90. Bicarb = 4.0 mM

•Urine is negative for ketones.

•Anion Gap = (Na+K) - bic - chloride•

•ie: there are an excess of anions

What is the acid/base abnormality?

A. Respiratory acidosisB. Metabolic acidosisC. Respiratory alkalosisD. Metabolic alkalosis

pH 7.10PCO2 = 1.3 kPa (N 4-5)PO2 = 15 kPa

Case 4.

•What is the acid-base disturbance?

•pH 7.10 (acidosis)

•pCO2 = 1.3 kPa (very low)

Case 4.

•What is the acid-base disturbance?

•pH 7.10 (acidosis)

•pCO2 = 1.3 kPa (very low)

•Metabolic acidosis

Case 4.•ie: there are an excess of anions

•Not ketones

•What else ?•Methanol, ethanol, lactate

•Metformin in overdose can cause a lactic acidosis

•Lactate = 10 mM (N<2.0)

The Cori cycle:

•Glucose (muscle) Lactate

•Glucose Lactate

circulation

liverInhibited by metformin

Case 4.

•Why is he unconscious?

•pH 7.10 (acidosis)

•The brain cannot function in such an acidic pH.

Definition (type 2 diabetes)

•Fasting glucose > 7.0 mM

•Glucose tolerance test (75 grams glucose given at time 0)

•Plasma glucose > 11.1 mM at 2 hours

•(2h value 7.8 – 11.1 = impaired glucose tolerance).

Acid base graph: CID