Type B - LA - types

Q: What is Type B1, Type B2 and Type B3 Lactic acidosis?

Answer; Basically, there are 2 major types of Lactic acidosis: A and B (let's forget about type D for a while!!)

Type A lactic acidosis occurs in the setting of poor tissue perfusion or oxygenation. It is due to either overproduction or underutilization.

Overproduction: Circulatory, pulmonary, or hemoglobin transfer disorders are commonly responsible.

Underutilization: Liver disease, gluconeogenesis inhibition, thiamine deficiency, and uncoupled oxidative phosphorylation

Type B lactic acidosis is when there is no evidence of poor tissue perfusion. Type B is divided into 3 subtypes.

• Type B1 is associated with systemic diseases such as renal and hepatic failure, diabetes, and malignancy.
• Type B2 is caused by drugs and toxins, including biguanides, alcohols, iron, isoniazid, and salicylates. HIV drugs have been described, too.
• Type B3 is due to inborn errors of metabolism.

#metabolism

References:

1. Seheult J, Fitzpatrick G, Boran G. Lactic acidosis: an update. Clin Chem Lab Med. 2017 Mar 1;55(3):322-333. doi: 10.1515/cclm-2016-0438. PMID: 27522622.

2. Claudino WM, Dias A, Tse W, Sharma VR. Type B lactic acidosis: a rare but life threatening hematologic emergency. A case illustration and brief review. Am J Blood Res. 2015 Jun 15;5(1):25-9. PMID: 26171281; PMCID: PMC4497494.