# A 75-year-old client on chronic metformin 1000 mg orally twice daily presents with new muscle aches, fatigue, abdominal pain, hyperventilation, and Kussmaul respirations. Vitals: BP 92/58, HR 110, temp 35.6°C. Labs: serum lactate 9 mmol/L (normal

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=375052&lang=en  
> language: en  
> subject: Adverse Effects/Contraindications/Interactions  
> category: PA

## Question

A 75-year-old client on chronic metformin 1000 mg orally twice daily presents with new muscle aches, fatigue, abdominal pain, hyperventilation, and Kussmaul respirations. Vitals: BP 92/58, HR 110, temp 35.6°C. Labs: serum lactate 9 mmol/L (normal

## Option

1. Administer activated charcoal 50 g to reduce metformin absorption, initiate supplemental oxygen to manage Kussmaul respirations, obtain a point-of-care glucose to rule out hypoglycemia as the cause of symptoms, monitor for resolution of abdominal pain, and continue metformin after the client stabilizes.
2. Hold metformin immediately, prepare for IV fluid resuscitation, anticipate transfer to ICU and possible hemodialysis to remove metformin and correct severe lactic acidosis, monitor airway/respiratory status closely, and notify the provider; consider IV sodium bicarbonate per protocol for severe acidemia. **✔ Correct answer**
3. Initiate empiric broad-spectrum antibiotics for presumed sepsis, administer a 30 mL/kg crystalloid bolus of normal saline, obtain blood cultures and a serum lactate level, notify the provider of the suspected sepsis diagnosis, and monitor for a decrease in lactate levels as a sign of effective treatment.
4. Check fingerstick blood glucose, administer regular insulin IV per DKA protocol for suspected diabetic ketoacidosis, begin 0.9% normal saline infusion at 500 mL per hour, monitor potassium levels for hypokalemia, and continue metformin to manage the underlying diabetes once the blood glucose is normalized.

**Correct answer: 2**

## Explanation

Metformin-associated lactic acidosis (MALA) — emergency
Classic MALA presents with the constellation: chronic metformin user, recent precipitant (CI-AKI from contrast, dehydration, sepsis, hypoxia, hepatic disease, alcohol, heart failure exacerbation), and the clinical/lab picture above:
• Symptoms: muscle aches, fatigue, weakness, malaise, abdominal pain, nausea/vomiting, hyperventilation, Kussmaul respirations.
• Vitals: hypotension, tachycardia, hypothermia.
• Labs: serum lactate >5 (often >10), pH 15-20, pH

## In-depth explanation

Clinical reasoning summary
Metformin-associated lactic acidosis (MALA) — emergency
Classic MALA presents with the constellation: chronic metformin user, recent precipitant (CI-AKI from contrast, dehydration, sepsis, hypoxia, hepatic disease, alcohol, heart failure exacerbation), and the clinical/lab picture above:
• Symptoms: muscle aches, fatigue, weakness, malaise, abdominal pain, nausea/vomiting, hyperventilation, Kussmaul respirations.
• Vitals: hypotension, tachycardia, hypothermia.
• Labs: serum lactate >5 (often >10), pH 15-20, pH

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