Patient came to ED with uncontrolled diabetes, urine test showed ketone positive. ABG reports showed pH - 6.25, pCO2 - 39 pO2 - 55 and blood glucose is 600 mg/dL. Which of the following condition is present?

1. A

   Respiratory acidosis

2. B

   Respiratory alkalosis

3. C

   Metabolic acidosis

4. D

   Metabolic alkalosis

Appeared in: AIIMS Delhi NO- 2019

Explanation

• The patient's pH of 6.25 is severely acidic (normal range: 7.35-7.45), which immediately points to a state of acidosis.
• The pCO₂ (respiratory parameter) is 39 mmHg, which is within the normal range (35-45 mmHg). This indicates that the acidosis is not caused by a respiratory problem.
• Since the condition is acidosis and the cause is not respiratory, it must be metabolic in origin.
• The clinical context of uncontrolled diabetes, high blood glucose (600 mg/dL), and positive ketones confirms Diabetic Ketoacidosis (DKA), a classic cause of metabolic acidosis.

Why Other Options Were Wrong

• Option A: In respiratory acidosis, the primary problem is CO₂ retention due to hypoventilation. This would result in an elevated pCO₂ (greater than 45 mmHg), which is not seen in this patient (pCO₂ is 39 mmHg).
• Option B: Respiratory alkalosis is characterized by a high pH (greater than 7.45) and a low pCO₂ (less than 35 mmHg) due to hyperventilation. This patient has a low pH (acidosis).
• Option D: Metabolic alkalosis involves a high pH (greater than 7.45) and typically a high bicarbonate (HCO₃⁻) level. This patient's pH is severely acidic (6.25).

Related Visual

Clinical Relevance

• Nursing practice connection: Knowing ABG Interpretation in Diabetic Ketoacidosis (DKA) helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
• Recognizing metabolic acidosis in a diabetic patient is a critical nursing skill, as DKA is a life-threatening emergency requiring immediate intervention with insulin and IV fluids.
• Nurses must closely monitor blood glucose, electrolytes (especially potassium), and neurological status during DKA treatment, as rapid shifts can occur when insulin therapy is initiated.
• What if the pCO₂ was low (e.g., 25 mmHg)? This would indicate respiratory compensation (Kussmaul respirations), where the body is trying to blow off CO₂ to counteract the metabolic acidosis. The primary diagnosis would still be metabolic acidosis, but with partial respiratory compensation.

How to Approach the Question

• First, analyze the clinical context: 'uncontrolled diabetes', 'ketone positive', and 'high blood glucose' are hallmark signs of Diabetic Ketoacidosis (DKA).
• Next, look at the pH. A value of 6.25 is well below the normal range of 7.35-7.45, immediately identifying the condition as 'acidosis'. This eliminates the 'alkalosis' options.
• Then, examine the pCO₂ (the respiratory parameter). A value of 39 mmHg is within the normal range (35-45 mmHg). This tells you the problem is not primarily respiratory.
• Since the condition is 'acidosis' but not 'respiratory', you can confidently conclude that it must be 'metabolic acidosis'.

Concept Tested & Keywords

• Concept Tested: ABG Interpretation in Diabetic Ketoacidosis (DKA)
• Stem keywords: uncontrolled diabetes, ketone positive, ABG, pH - 6.25, pCO2 - 39, blood glucose is 600 mg/dL
• Lead-in keywords: Which of the following condition
• Clinical cues: The combination of hyperglycemia, ketonuria, and low pH is the classic triad for Diabetic Ketoacidosis (DKA).
• Negative lead-in flag: false

Question ID

QCa5ujFmKRQYXGYExNIq77

Copy ID

Reference Book

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 1 (pp 26-370 of 370) p. 199-201

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 2 — Subpart A (pp 1-239 of 478) p. 82-84