Question 1:

PH = 7.47 that is mild alkalaemia.

Hco3 = 34 (> 24) then it is metabolic alkalosis.

Next step we calculate compensation, Expected PCO2 is 0.7 x HCO3 + 20 = 43.8

PCO2 = 38, less than expected. So we have associated respiratory Alkalosis.

K = 2.6 (between 3 and 2.5) that is moderate hypokalaemia

Cl = 93 that is mild hypochloremia

So the patient has combined metabolic and respiratory alkalosis associated with moderate Hypokalaemia.

*** Hypochloremia is usually associated with metabolic alkalosis.

Question 2:

Going through CLEVER PD mnemonic,

C – contraction (dehydration)

L – liquorice (diuretic), laxative abuse

E – endocrine (Conn’s, Cushing’s)

V – vomiting, GI loss (villous adenoma)

E – excess alkali (antacids)

R – renal (Bartter’s), severe K depletion

P – post hypercapnia

D – diuretics,

• Liquorice, laxatives, diuretics and excessive alkali intake can be excluded by taking good history.
• Vomiting, GI loss and Post hypercapnia were also excluded by history taking.
• Patient was euvolemic / not dehydrated on examination.

Remaining possibilities are endocrine and renal causes.

• Conn’s syndrome and Cushing’s syndrome cause hypertension and hypokalemia.
• Bartter Syndrome is usually diagnosed during childhood and is usually associated with low/normal blood pressure.
• Gitelman syndrome is possible but it is very rare.

hypokalaemia can cause metabolic alkalosis and it can be caused by metabolic alkalosis.

For respiratory alkalosis: This patient was hyperventilating with SPO2 of 100%. She was anxious.

 Question 3:

 The most important part of the management is potassium replacement. We need to consider magnesium replacement before replacing potassium.

 Then treating the cause,

• Urinary chloride level help categories the differential in metabolic alkalosis.

Low urinary chloride (< 20 meq/l) that occur in GI loss (both upper and lower), post hypercapnia and prior diuretics use.

• All other causes cause high urinary chloride (> 20 meq/l), that include:  active diuretics use, Conn’s Syndrome, Bartter Syndrome, Gitelman Syndrome, Alkali administration and severe hypokalemia.

• hyperaldosteronism is diagnosed by measuring the blood levels of aldosterone and renin.

• Metabolic alkalosis can be either saline responsive or saline resistant (Chloride responsive or chloride resistant).

Saline responsive that usually include all the causes except (Hyperaldosteronism, Cushing’s Syndrome, Bartter Syndrome and Gitelman Syndrome).

For saline responsive hyperkalemia we use IV N/S with/without carbonic anhydrase inhibitors.

For saline resistant causes treat the cause with/without spironolactone (aldosterone antagonist).