RHABDOMYOLYSIS AND ACUTE KIDNEY INJURY SECONDARY TO LEGAL HIGHS

INTRODUCTION

Legal highs, or designer drugs, have seen a substantial increase in use since the 1990s. Not only has there been a growth in their use and availability, especially via the internet, but also in the number and type of these drugs available. Individuals using these drugs are attempting to obtain positive emotional effects, but we have noted an associated increasing incidence of adverse renal effects. This is highlighted by two cases recently admitted to our renal unit having taken legal highs, presented with rhabdomyolysis, secondary oliguric acute kidney injury (AKI) and subsequently required short term renal replacement therapy.

CASE 1

31 year old man admitted with a short history of muscle pains, abdominal pains and vomiting following two intramuscular injections of ‘Mephedrone’, a legal high with similar effects to ecstasy (MDMA), which he had purchased from the internet. His blood results showed rhabdomyolysis with a serum Creatine Kinase of 92,700 Units/L and a Creatinine of 867 micromol/L. He had severe oliguric AKI and commenced on renal replacement therapy, initially requiring additional intensive care support. He required five sessions of haemodialysis and subsequently recovered. His Creatinine resolved to 94 micromol/L and his rapid recovery meant a renal biopsy was not performed.

CASE 2

37 year old lady admitted following an 18 hour long lie at home and a history of anuria for three days. She reported having inhaled 4 ‘lines’ of ‘China White’, a legal high marketed as similar to cocaine, and injecting approximately 500-750mg of heroin 24 hours prior to admission. On admission she had a metabolic acidosis and rhabdomyolysis with a Creatine Kinase of 102,806 Unit/L at its peak and a Creatinine of 241 micromol/L. She also developed a left lower zone pneumonia, acute delirium and initially required intensive care support and haemofiltration. Subsequently she was stepped down to the renal unit to continue acute haemodialysis. She required two weeks of acute dialysis before her urine output increased and her renal function improved. At discharge her Creatinine was 134 micromol/L. A renal biopsy was not performed.

DISCUSSION

The presentation of these patients shortly after taking a legal high, with significantly elevated Creatine Kinase levels and severe oliguric AKI, makes rhabdomyolysis secondary to these drugs the most likely cause. The difficulty with cases involving legal highs is the lack of detectability with routine toxicology testing, the increasing variety of legal highs available, and the additional unknown toxic substances these drugs are mixed with. As legal highs continue to gain popularity we believe the presentation of patients with nephrotoxicity secondary to these drugs will increase. In summary, these cases highlight the importance for clinicians to consider legal highs in their differential diagnosis of rhabdomyolysis and AKI, particularly in young people.