Hyperosmolar metabolic acidosis and intravenous Lorazepam

Hyperosmolar metabolic acidosis in burn patients exposed to glycol based topical antimicrobials-A systematic review

BACKGROUND

The well documented susceptibility of burn patients to acquired infections via damaged skin mandates application of antimicrobial agents. These agents are dissolved in various vehicles that augment skin absorption thus allowing greater efficacy. Polyethylene glycol (PEG) and Propylene glycol (PropG) are among the most commonly used vehicles, and both have been used in numerous medications and cosmetic products over the past few decades. Rarely, burn patients treated with agents containing these glycols present with a life threatening systemic toxidrome of hyperosmolar metabolic acidosis. We present a systematic review of outcomes in burn patients treated with similar agents.

METHODS

Relevant studies were identified through systematic searches conducted in MEDLINE (Ovid), Embase (Ovid), CENTRAL (Ovid), and Web of Science (Thomson Reuters), from database inception to August 4th, 2016. All publications of clinical burn patient studies included at least one arm receiving a glycol based topical therapy.

RESULTS

A total of 61 studies involving 10,282 patients and 4 different antimicrobial medications fulfilled the inclusion criteria. Nine burn patients (0.09%) were documented to present with hyperosmolar metabolic acidosis during topical silver sulfadiazine treatment. Propylene glycol isolated from their blood accounted for the high osmole gap.

CONCLUSION

This first systematic review found very few cases of documented hyperosmolar metabolic acidosis, all within one study that had set to specifically explore this toxidrome. High index of suspicion with frequent osmolar gap monitoring may help identify future toxicities in a timely manner.

Treatment of lactic acidosis: appropriate confusion

BACKGROUND

Lactic acidosis (LA) is common in hospitalized patients and is associated with poor clinical outcomes. There have been major recent advances in our understanding of lactate generation and physiology. However, treatment of LA is an area of controversy and uncertainty, and the use of agents to raise pH is not clearly beneficial.

AIM AND METHODS

We reviewed animal and human studies on the pathogenesis, impact, and treatment of LA, published in the English language and available through the PubMed/MEDLINE database. Our aim was to clarify the physiology of the generation of LA, its impact on outcomes, and the different treatment modalities available. We also examined relevant data regarding LA induced by medications commonly prescribed by hospitalists: biguanides, nucleoside analog reverse-transcriptase inhibitors (NRTIs), linezolid, and lorazepam.

RESULTS/CONCLUSIONS

Lactic acid is a marker of tissue ischemia but it also may accumulate without tissue hypoperfusion. In the latter circumstance, lactic acid accumulation may be an adaptive mechanism-a novel possibility quite in contrast to the traditional view of lactic acid as only a marker of tissue ischemia. Studies on the treatment of LA with sodium bicarbonate or other buffers fail to show consistent clinical benefit. Severe acidemia in the setting of LA is a particularly poorly studied area. In the settings of medication-induced LA, optimal treatment, apart from prompt cessation of the offending agent, is still unclear.

Hyperosmolar, increased-anion-gap metabolic acidosis and hyperglycemia after etomidate infusion

Hyperosmolar increased-anion-gap metabolic acidosis without hyperglycemia has been reported after infusions of etomidate and other medications containing propylene glycol. We report a case of this biochemical abnormality with severe hyperglycemia. Cessation of the etomidate infusion along with other supportive measures resulted in prompt resolution of the metabolic acidosis and hyperglycemia.

Recognition, treatment, and prevention of propylene glycol toxicity

Propylene glycol is a commonly used solvent for oral, intravenous, and topical pharmaceutical preparations. Although it is considered safe, large intravenous doses given over a short period of time can be toxic. Underlying renal insufficiency and hepatic dysfunction raise risk for toxicity. Toxic effects include hyperosmolality, increased anion gap metabolic acidosis (due to lactic acidosis), acute kidney injury, and sepsis-like syndrome. Treatment of toxicity includes hemodialysis to effectively remove propylene glycol. Prevention is best achieved by limiting the dose of propylene glycol infused.