Clinician contributions Critical Care Emergency Endocrine Nephrology

Renal Failure in Type II Diabetes – Dr Drew Wenck

Intensive Care and Department of Emergency Medicine Case.

 

A 47 year old Indigenous male presents with a 4 day history of vomiting and diarrhoea. He states he feels short of breath and lethargic.
He has a history of Type II Diabetes Mellitus for which he takes Metformin 500mg bd.

His initial observations are:

PR:         110/min (Sinus tachycardia on monitor)
BP:         95/70 mm/Hg
RR:        34/min with accessory muscle use

You order a chest x-ray, which is unremarkable.

You perform some point-of-care testing (on 6 litres of O2 via a Hudson mask) and the results are below:

ABG & Electrolytes

 

What is your differential diagnosis?

  • Diabetic with ketoacidosis – (glucose is normal)
  • Metformin induced lactic acidosis
  • Poisoning

You next obtain a lactate level, which is 18 mmols/l.

 

Learning Points:

  • Patients with type II diabetes often go into Acute Renal failure from relatively minor insults.
  • Metformin is renally excreted.
  • When metformin accumulates it is a mitochondrial poison. The Krebs cycle is not operative so pyruvate will shunt out to lactate to regenerate NAD to enable glycolysis to continue.
  • Treatment is haemodialysis to remove the metformin.

 

Some relevant reading:

Prescribing in renal disease; Aust Prescr 2007;30:17-20 | 1 February 2007

http://www.australianprescriber.com/magazine/30/1/17/20

 

Metformin-associated Lactic Acidosis

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