Lactate Metabolism and Cori Cycle

A 35-year-old woman with chronic liver disease presents with lactic acidosis (pH 7.28, lactate 8 mmol/L). Her glucose is 45 mg/dL. Which of the following best explains the combination of hypoglycemia and lactic acidosis in this clinical scenario?

A 38-year-old male with a history of alcohol abuse presents to the emergency department with severe lactic acidosis (pH 7.18, lactate 12 mmol/L). Clinical examination reveals hepatomegaly and signs of cirrhosis. Which investigation would be most appropriate to assess the liver's capacity to clear lactate and confirm impaired gluconeogenesis?

A 32-year-old male athlete undergoes high-intensity interval training. Blood lactate rises to 12 mmol/L (normal fasting: 1–2 mmol/L). After exercise cessation, lactate returns to baseline within 1 hour. Which organ is responsible for the most significant clearance of this elevated lactate?

Regarding the Cori cycle and lactate metabolism, all of the following statements are true EXCEPT:

A 28-year-old male marathon runner presents to the emergency department with severe muscle pain, dark urine, and a serum lactate of 8.2 mmol/L (normal: 0.5–2.2 mmol/L) after completing a 42 km race. His liver function tests are normal, and blood glucose is 95 mg/dL. Arterial blood gas shows pH 7.28 with HCO₃⁻ of 14 mEq/L. What is the most appropriate immediate next step in management?