D-Lactic acidosis

OVERVIEW

  • aka D-lactic encephalopathy
  • rare cause of high anion gap metabolic acidosis (HAGMA)
  • typically occurs in patients short bowel syndrome or following jejuno-ileal bypass surgery
  • usual L-lactate assay is normal, so a high index of suspicion is needed in at-risk patients

CAUSE

Risk factors

  • abnormal gut structure (blind loops, short gut syndrome, jejuno-ileal bypass surgery)
  • ischaemia
  • small intestinal bacterial overgrowth (SIBO)
  • antibiotics that select out Lactobacillus and Streptococcus bovis subtypes
  • high carbohydrate load
  • the possible causative role of probiotics is controversial (Rao et al, 2018)

Mechanism

  • malabsorbed carbohydrate is fermented by an abnormal bacterial flora in the colon
  • this produces excessive amounts of D-lactate
  • acidic pH generated as a result of D-lactate production further propagates production of D-lactic acid, giving rise to a vicious cycle
  • high amounts of D-lactate are absorbed into the circulation, resulting in an elevated concentration of D-lactate in the blood
  • unclear if D-lactate itself, or other (co-absorbed) factors, is responsible for neurological symptoms

CLINICAL FEATURES

  • Neurological symptoms
    • altered mental status, slurred speech, and ataxia (may appear “drunk”)
    • “brain fogginess”
  • Presence of risk factors
  • absence of another attributable cause

INVESTIGATIONS

  • high anion gap (HAGMA)
  • L-lactate normal (standard lactate assay)
  • elevated plasma D-lactate level (> 3 mmol/L is diagnostic)
  • normal glucose

MANAGEMENT

  • supportive, including:
    • management of confusional state and falls risk
    • correction of acidosis (e.g. renal replacement therapy in severe cases)
  • withdraw contributing factors
  • restrict enteral carbohydrate intake
  • antibiotics to clear causative colonic flora (rarely)
  • for refractory cases, consider surgery (e.g. small intestine transplant, lengthening procedures)

References and Links

Journal articles

  • Kowlgi NG, Chhabra L. D-lactic acidosis: an underrecognized complication of short bowel syndrome. Gastroenterol Res Pract. 2015;2015:476215. [pubmed] [article]
  • Petersen C. D-lactic acidosis. Nutr Clin Pract. 2005;20(6):634-45. [pubmed]
  • Rao SSC, Rehman A, Yu S, Andino NM. Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis. Clin Transl Gastroenterol. 2018;9(6):162. [pubmed] [article]
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Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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