Rhabdomyolysis is the breakdown of striated muscle. The resultant leakage of the intracellular muscle constituents into the circulation may lead to acute renal failure. Trauma to the muscles is the most common cause of rhabdomyolysis. Other causes include exertion, muscle hypoxia, genetic defects, infections, body temperature changes, metabolic and electrolyte disorders, as well as drugs and toxins.6
The seasonal flu vaccination that is described in this case report, Imuvac 2009/2010 produced by Solvay Healthcare (Southampton, United Kingdom), contains haemagglutinin and neuraminidase antigens of three different inactivated influenza viruses propagated in fertilised hens’ eggs. Muscular side-effects such as myalgia and arthralgia are described as occurring in more than 1/100 but less than 1/10 cases.7
Musso et al8
report a case in Argentina of a 73-year-old man who did not appear to have any other risk factors for developing rhabdomyolysis other than receiving an influenza vaccine (the report did not specify which particular vaccine).
Muscle syndromes ranging from myalgia to rhabdomyolysis have also been reported to complicate a number of acute viral infections, including those caused by the influenza A and B viruses.9
The incidence of rhabdomyolysis associated with viral infections is not clearly defined; however, a case series of 63 patients with influenza pneumonia reported an incidence of rhabdomyolysis as 9.5%.10
Statins are well-recognised to be associated with muscle syndromes such as myalgia, myositis and myopathy. In addition, rhabdomyolysis with acute renal impairment secondary to myoglobinuria has also been reported and the Committee on Safety on Medicines (CSM) estimate it to occur approximately once in every 100 000 treatment years. The CSM also advise that the use of concomitant treatment with drugs that increase plasma-statin concentration (eg, ciclosporin) increases the risk of muscle toxicity as does concurrent treatment with a fibrate and a statin.11
There have been two reported cases of acute renal failure secondary to rhabdomyolysis triggered by an influenza vaccination on a background of cholesterol-lowering treatment. The first of these case reports describe a 68-year-old man who was treated with both cerivastatin and bezafibrate and developed acute renal failure and rhabdomyolysis after receiving the influenza vaccine in Israel (again this case report does not specify which particular vaccine).12
The second case report describes a 57-year-old man who developed rhabdomyolysis with acute renal failure following an inactivated influenza vaccine (inactivated split virion—Avantis Pasteur) in a renal transplant recipient who has been on simvastatin and ciclosporin A treatment.13
We believe this to be the first report of rhabdomyolysis with acute renal failure triggered by influenza vaccination in a patient whose only risk factor was concurrent simvastatin use.
A pilot study in Israel14
looked at 98 patients (52 receiving statins, 46 controls) who received an influenza vaccine (again this article does not specify which particular vaccine). They did not find any clinical or laboratory evidence to support influenza vaccination being associated with myopathy in patients taking statins. Given the small number of patients involved in this study, as well as the uncertainty regarding the specific vaccine that was administered, it is difficult to interpret the significance and applicability of these findings to this case report.
We believe given the time course of events and the absence of other causes, this case represents rhabdomyolysis with acute renal failure triggered by the influenza vaccine in a patient taking simvastatin. We conclude that while this clinical picture is extremely rare, it is an important complication that healthcare professionals need to be aware of, and maintain a high index of suspicion for, so that early recognition can enable the prompt use of appropriate treatment and, thus, diminish the renal dysfunction associated with this disorder. This is especially pertinent this coming influenza season with the increased awareness and uptake of influenza vaccinations.
- Influenza vaccination may rarely trigger rhabdomyolysis in similar patients being treated with a statin.
- Myositis and the possibility of rhabdomyolysis should be considered in any individual presenting with severe myalgia or muscle weakness who has recently had the influenza vaccine and is also taking a statin or other myotoxic drugs.
- Patients using statins should be advised to seek medical advice if they develop muscle pains after an influenza vaccine.