Lab case 396 interpretation

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Question 1:

PH = 7.30 that is mild acidaemia.

HCO3 = 16 mmol/L (>24) so we have metabolic acidosis.

Next, we need to calculate the anion gap and the compensation (using Winter’s formula)

AG = Na – (HCO3 + CL), that is 127- (16+100) = 11, So we have normal anion gap metabolic acidosis.

To calculate the compensation using Winter’s formula (expected PCO2 = 1.5 x HCO3+ 8 (+/- 2) = 32. This is very close to 33 so we can say that the compensation is as expected or there is no associated respiratory process.

Other findings, Na = 127 that is mild hyponatrtaemia. K = 5.8 that is mild hyperkalaemia.

Lactate = 2.8, mild hyperlactataemia.

Blood glucose = 2.8 (> 3 in non-diabetic patient), hypoglycaemia.

Considering the causes of normal anion gap metabolic acidosis, using the USED CARP mnemonic:

-Ureteroenterostomy
-Small bowel fistula
-Extra Chloride
-Diarrhoea
-Carbonic anhydase inhibitors
-Addisons disease
-Renal tubular acidosis
-Pancreatic fistula

Among the potential causes above, Addison’s disease causes hyperkalaemia and hyponatraemia with loss of bicarbonate due to Aldosterone Hormone deficiency. That is usually secondary to adrenal glands failure.

Question 2:

Hypoglycaemia is secondary to cortisol deficiency, this doesn’t usually happen in adult patients (more frequent in children under 5 years). However, it can happen in a fasting state or as a reactive hypoglycemia.

Reactive hpoglycaemic symptoms may be caused by the mildly decreased secretion of an adrenal cortical hormone as a counter-regulatory hormone against the excessive secretion of insulin after a meal.

This can be one of the signs of Adrenal fatigue.

Question 3:

Causes of non-diabetic hypoglycemia are divided into 2 categories.

1- Reactive hypoglycemia, caused by too much insulin in the blood:

  • Having pre-diabetes or a patient at risk of diabetes, that is due to production of too much insulin
  • Stomach surgery, which can make food pass too quickly into small intestine.
  • Rare enzyme deficiencies that make it hard for the body to break down food.

2- Fasting hypoglycemia​, this can be caused by:

  • Medicine such as sulfa drugs, salicylates, pentamidine and quinine.
  • Alcohol, especially with binge drinking
  • Serious diseases affecting the kidney or the liver.
  • Hormonal deficiency, such as cortisol, GH, glucagon or adrenaline
  • Tumors of the pancreas that produces insulin or other tumors that produces similar hormone called IGF-II

This is a case from the archive.