Hyperlactataemia with acute kidney injury following community assault: cause or effect?

Crush injury is a common presenting clinical problem in South African trauma patients, causing acute kidney injury (AKI). It has been theorised previously that the AKI was not due to an anaerobic phenomenon. A previous local study noted the presence of a mild hyperlactataemia among patients with crush syndrome, but the significance and causes of this was not fully explored. This study aimed to examine the incidence of hyperlactataemia in patients with crush syndrome presenting to a busy emergency department (ED) in rural South Africa.

The study was conducted at Edendale Hospital in KwaZulu-Natal province in South Africa from 1 June 2016 to 31 December 2017. All patients from the ED who had sustained a crush injury secondary to a mob assault were included in the study. Patients with GCS on arrival of < 13 or polytrauma were excluded from analysis. The primary outcome of interest was the presence of hyperlactataemia (> 2.0mmol/L) on presentation. The Kidney Disease Improving Global Outcomes (KDIGO) criteria were used to diagnose and stage AKI as a secondary outcome.

A total of 84 patients were eligible for analysis. Sixty-nine (82%) patients presented with hyperlactataemia. The median serum lactate was 4.9mmol/L (IQR 2.3-7.2mmol/L). Fifteen (18%) patients were diagnosed with AKI on presentation according to serum creatinine. Ten patients were diagnosed as Stage 1, three were Stage 2 and two Stage 3 AKI respectively. There was no difference in the incidence of AKI in patients with or without hyperlactataemia (p = 0.428). Time from injury to presentation was a median 365 minutes (IQR 180-750 minutes). Six (7%) patients were admitted to high care unit and nine (11%) were admitted to the intensive care unit (ICU). No patients died within 48 hours of admission. Two patients received renal replacement therapy during the first 48 hours of admission to hospital.

Hyperlactataemia is a common feature of patients presenting to the ED following crush syndrome secondary to beatings received during interpersonal violence. The origin of this hyperlactataemia is currently unknown. Further research needs to be conducted into the origin of the hyperlactataemia and its clinical significance. In this cohort, the utilisation of RRT was low but the incidence of AKI was high and developed rapidly following the injury. The utilisation of RRT also needs to be further studied in larger patient populations in South Africa to make local clinical recommendations for use.