Lab case 268 interpretation

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Question 1:

PH = 7.28, that is mild acidaemia.

HCO3 = 14 (>24), so we have metabolic acidosis. Next, we need to calculate the Anion Gap and Compensation using Winter’s formula.

AG = Na – (Cl + HCO3) = 16. So we have high anion gap metabolic acidosis.

Winter’s formula, that is expected PCO2 = 1.5 x HCO3 + 8 (+/- 2), accordingly expected PCO2 in this case is 27 – 31. So we have fully compensated HAGMA, no additional respiratory pathological process.

Next we calculate the delta ratio, (AG-12/24-HCO3) = 4/10 = 0.4. So we have mixed HAGMA and NAGMA. ( ratio between 0.4 – 0.8).

Other abnormal findings:

  • This most significant and important abnormal finding is the hypoglycemia, Glucose of 2.9 mmol/L (less than 3 in non-diabetic patient).
  • Na = 132 mmol/L, that is mild hyponatraemia
  •  K = 3.1 mmol/L, that is mild hypokalaemia.
  •  Lactate = 5.8 mmol/L, that is severe hyperlactataemia
  •  Ketones = 6.2 mmol/L that is severe ketosis

Question 2: 

Looking at the simple way to remember the causes of HAGMA (LTKR), this patient have high ketones and high lactate.

The three major types of ketosis are:

  • Starvation ketosis.
  • Alcoholic ketoacidosis.
  • Diabetic ketoacidosis

Causes of high Lactate are:

  •  Shock (Distributive, Cardiogenic, Hypovolemic or Obstructive)
  • Post cardiac arrest
  • Regional tissue ischemia
  • DKA
  • Drugs and toxins ( Alcohol, Cocaine, Carbon monoxide and cyanide)
  • Some pharmacological agents (Nucleoside reverse transcriptase inhibitors, Metformin, adrenaline, Beta2 agonists, paracetamol toxicity)
  • Anaerobic muscle activity (Seizures, heavy exercise and excessive work of breathing)
  •  Liver failure
  • Malignancy
  • Thiamine deficiency
  • Some Mitochondrial diseases.

The initial thoughts about the causes of HAGMA in this patient was Alcohol related, especially Ethanol may cause hypoglycemia by impairing hepatic glucose production, even in the absence of underlying liver disease.

Causes of NAGMA (using the pneumonic USED CARP)

  • Ureteroenterostomy/Ureterosigmoid connection.
  • Small bowel fistula.
  • Extra chloride (NH4Cl or amino acid chlorides 2° to TPN).
  • Diarrhea.
  • Carbonic Anhydrase inhibitors, CaCl ingestion, cholestyramine ingestion.
  • RTA types I (distal), II, (proximal), and IV (hyporeninemic hypoaldosteronism).
  • Adrenal insufficiency (e.g. Addison’s disease)
  • Pancreatic fistula, Parenteral nutrition (TPN), hyperPTH, Post-hypocapnia

In the presence of hyponatraemia, the plasma chloride level may be normal despite the presence of NAGMA, this could be considered as a relative hyperchloraemia.

Alcohol as a cause of this presentation was excluded as the patient didn’t drink alcohol for a while.

The cause in this case was starvation ketosis with dehydration.

Working in the ICU COVID area exposes the body to extreme conditions, Nurses usually work 12 hours shift and they get 1 hour break. They can easily lose 3 liters of sweat per shift.

After night shift this patient was tired, slept immediately and didn’t eat anything.

This patient was admitted to the ICU, rehydrated gradually. She needed about 6 L of fluids then she was discharged with normal blood results.