Mesenteric Ischemia: This condition is characterized by insufficient blood flow to the intestines, leading to tissue ischemia. It can cause high lactic acidosis due to anaerobic metabolism, along with nausea, vomiting, and severe abdominal pain. The combination of these symptoms, especially in the context of risk factors such as atrial fibrillation, heart failure, or recent vascular surgery, makes mesenteric ischemia a leading consideration.

Sepsis: Sepsis, particularly when caused by abdominal infections (e.g., cholecystitis, appendicitis, or diverticulitis), can lead to lactic acidosis due to tissue hypoperfusion and hypoxia. Nausea, vomiting, and abdominal pain are common accompanying symptoms.
Diabetic Ketoacidosis (DKA): Although DKA primarily presents with hyperglycemia and ketosis, it can also cause lactic acidosis, especially if there is significant dehydration or if the patient has a co-existing condition leading to tissue hypoperfusion. Abdominal pain and nausea are common in DKA.
Gastroenteritis: Severe gastroenteritis, especially if caused by invasive pathogens or if leading to significant dehydration, can result in lactic acidosis. Symptoms include nausea, vomiting, abdominal pain, and diarrhea.

Intestinal Obstruction: This condition can lead to ischemia of the bowel wall if not promptly relieved, resulting in lactic acidosis. Symptoms include severe abdominal pain, nausea, vomiting, and obstipation.
Pancreatitis: Both acute and chronic pancreatitis can cause abdominal pain, nausea, vomiting, and potentially lactic acidosis if there is significant necrosis or if the patient develops systemic inflammatory response syndrome (SIRS).
Toxic Ingestions (e.g., Salicylates, Ethylene Glycol, Methanol): Certain toxic ingestions can lead to metabolic acidosis, including lactic acidosis, and may present with gastrointestinal symptoms among others.

Mitochondrial Myopathies: These are a group of disorders that affect the mitochondria, leading to impaired energy production. They can cause lactic acidosis, especially during periods of high energy demand or stress, and may present with a variety of symptoms including gastrointestinal issues.
Malignant Diseases (e.g., Lymphoma): Certain malignancies can lead to lactic acidosis, either through tumor lysis syndrome or through the production of lactate by tumor cells. Abdominal pain and nausea can be part of the presentation if the malignancy involves abdominal organs.
Congenital Disorders of Glycolysis: These are rare genetic disorders that affect glycolysis, leading to the accumulation of lactate. They can present with episodes of lactic acidosis triggered by stress, fasting, or high carbohydrate intake, and may include gastrointestinal symptoms.