NAGMA AGMA HAGMA

Question 1

What is NAGMA?

Answer 1

Normal Anion Gap Metabolic Acidosis is a type of acidosis where the anion gap remains within the normal range (4–12 mmol/L).

Question 2

What are the main causes of NAGMA?

Answer 2

• Gastrointestinal bicarbonate loss: Diarrhea, ileostomy.
• Renal bicarbonate loss: Renal tubular acidosis (RTA).
• Hyperchloremia: Due to excessive normal saline administration.

Question 3

How does chloride behave in NAGMA?

Answer 3

Chloride increases to compensate for bicarbonate loss, maintaining electroneutrality.

Question 4

What are the types of renal tubular acidosis (RTA) associated with NAGMA?

Answer 4

• Type 1 (Distal RTA): Impaired H+ secretion.
• Type 2 (Proximal RTA): Impaired bicarbonate reabsorption.
• Type 4 RTA: Hypoaldosteronism leading to hyperkalemia.

(Type 3??)

Question 5

What is AGMA?

Answer 5

Anion Gap Metabolic Acidosis is acidosis with an increased anion gap (>12 mmol/L), indicating the presence of unmeasured anions.

Question 6

What is the anion gap formula?

Answer 6

AG = (Na+ + K+) – (Cl- + HCO3-).
(Potassium is sometimes omitted.)

Question 7

What are common causes of AGMA?

Answer 7

MUDPILES mnemonic:
- Methanol
- Uremia
- Diabetic ketoacidosis
- Propylene glycol
- Iron/Isoniazid
- Lactic acidosis
- Ethylene glycol
- Salicylates

Question 8

How does lactic acidosis contribute to AGMA?

Answer 8

Accumulation of lactic acid adds unmeasured anions (lactate), increasing the anion gap.

Question 9

Why does ketoacidosis cause AGMA?

Answer 9

Accumulation of ketone bodies (acetoacetate and beta-hydroxybutyrate) adds unmeasured anions.

Question 10

What differentiates HAGMA from AGMA?

Answer 10

HAGMA is a subtype of AGMA where the anion gap is significantly elevated (>20 mmol/L), usually indicating severe acidosis.

Question 11

What are examples of toxins causing HAGMA?

Answer 11

Methanol, ethylene glycol, and salicylates.

Question 12

How does kidney failure cause HAGMA?

Answer 12

Accumulation of sulfates, phosphates, and organic acids due to impaired excretion.

Question 13

What are typical blood gas findings in HAGMA?

Answer 13

• Low pH (<7.35).
• Low bicarbonate (<22 mmol/L).
• Elevated anion gap (>20 mmol/L).

Question 14

How do you differentiate NAGMA from AGMA?

Answer 14

• NAGMA: Normal anion gap, hyperchloremia.
• AGMA: Increased anion gap, presence of unmeasured anions.

Question 15

What is the clinical significance of hypoalbuminemia in AGMA or HAGMA?

Answer 15

Hypoalbuminemia lowers the expected anion gap, potentially masking acidosis.

Question 16

What compensatory mechanism is seen in metabolic acidosis?

Answer 16

Respiratory compensation via hyperventilation (Kussmaul breathing) to reduce PaCO2.

Question 17

What lab test can help differentiate HAGMA causes?

Answer 17

Serum osmolality to calculate the osmolar gap, which helps identify toxins like methanol or ethylene glycol.