Rhabdomyolysis is a life-threatening condition—and not one that is factored into a clinical diagnosis in pre-hospital cases often enough. The author's experience of such cases in clinical practice has guided further investigation and exploration of published literature to create an opportunity to learn about the condition, and raise much-needed awareness that people die from the untreated complications of rhabdomyolysis—and providers of pre-hospital care have a role to play in helping to identify it. This comment article will briefly review current practice and evidence, and highlight the need for further research and study into a rather alien condition.
Pathophysiology
To confidently recognise the clinical presentation of rhabdomyolysis, clinicians need to understand the pathophysiological changes that occur, and the symptoms such changes create. Rhabdomyolysis, by definition, is skeletal muscle breakdown where cellular contents are released into the circulating blood plasma including creatinine kinase (CK) and myoglobin. There are two pathways which commonly lead to the release of cellular contents.
The first is caused by a depletion of adenosine triphosphate (ATP) which affects the sodium/potassium/calcium pump at cellular level. These pumps control the internal cell environment and maintain homeostasis by removing sodium and calcium. ATP controls the levels of sodium, potassium and calcium within a cell; a failure to function creates an accumulation of sodium and calcium which leads to a surge in enzyme activity within the cell. This increased enzyme activity leads to the breakdown of the cell wall, releasing contents into the blood stream (Vanholder, 2000; Bosch, 2009; Khan, 2009).
The second form of cellular breakdown is a result of direct sarcolemmic injury, which can be seen in cases of trauma, and which allows the contents of the internal cell environment to be released.
In normal physiology, insignificant amounts of myoglobin are present in the blood stream and loosely attach to plasma, which prevents it from crossing the glomerulus and entering the renal system. Myoglobin has comparable properties to haemoglobin in that it carries and stores oxygen.
Glomerular filtration rates and renal blood flow decrease at a rate of approximately 10% per decade from the age of 40 years onward. This renders elderly people susceptible to developing rhabdomyolysis with acute renal failure (Bowker, 2006). An even greater more rapid decline is seen in adults with comorbidities including renal illness.
During rhabdomyolysis, the myoglobin volume within circulation is so great that it exceeds its ability to bind to plasma. Myoglobin bound together in copious quantities are then able to pass freely into the renal tubes (Hunter et al, 2006; Khan, 2009). The myoglobin, while in the renal tubes, re-absorbs water causing an increased concentration of myoglobin; blockages also occur as a result of this process (Walter and Catenacci, 2008).
This has exceptional clinical significance and acute kidney injury (AKI) can result directly from cellular contents entering the renal tubes. Rhabdomyolysis is considered as a diagnosis when creatinine kinase levels are five times the normal upper limit. Levels of this degree give a strong indication of AKI.
The initial clinical symptoms may only indicate a more common urinary tract infection. For example, flank pain, dark or tea-coloured urine, increased urine concentration and hypotension will occur.
ECGs are generally used as a diagnostic tool in cases of elderly falls; however, it is not well acknowledged in pre-hospital care that an ECG can aid with the diagnosis of rhabdomyolysis. Cardiac conduction abnormalities occur when there has been a sudden rise in potassium levels, as seen in rhabdomyolysis-induced AKI (Knott, 2016).
Destruction of the sarcolemma allows for the release of potassium into the blood stream which can cause a prolonged PR interval, wide QRS complex, reduced P-waves and peaked T-waves. In those who already have an abnormal ECG, the only sign of hyperkalaemia may be bradycardia.
However, rhabdomyolysis does not always present with significant symptoms initially. It can sometimes take up to 2 days for the symptoms to develop, making it more difficult to recognise in the pre-hospital environment. The rate at which the symptoms develop has a number of variable factors; the patient's comorbidities and length of time spent immobile are the most significant.
Pre-hospital significance
Rhabdomyolysis is not a naturally occurring condition in relation to the ageing process. The aetiology leading to rhabdomyolysis is varied; however, one of its leading causes is elderly falls with a period of immobilisation. In fact, elderly falls are the leading cause of rhabdomyolysis with secondary AKI (Henderson, 2015).
A report published in the Journal of Paramedic Practice highlights that within modern paramedic practice, ambulance services are increasingly encouraging a ‘see-and-treat’ approach, increasing the chances for the potentially life-threatening condition to be overlooked (Nellist and Lethbridge, 2013). The authors of the report argue that more training should be provided to paramedics to support the pre-hospital recognition of rhabdomyolysis, especially for elderly fallers who have had a period of immobility for more than 1 hour (Nellist and Lethbridge, 2013). This mirrors recommendations from earlier reports as far back the 1980s (Ratcliffe et al, 1984). However, despite a 34-year time frame, ambulance trusts and clinical training programmes are still failing to provide appropriate training and highlight the importance of recognising rhabdomyolysis with secondary AKI.
Over 50% of elderly people who fall are unable to get up from the floor by themselves, immediately putting them at an increased risk of developing complications such as fractures, hypothermia, rhabdomyolysis and pneumonia (Age UK, 2013). While there are many reasons why an elderly person can fall, muscle atrophy leads to a decrease in mass and strength. Researchers state that muscle atrophy is not only a contributing factor to a fall, it is also a contributing factor to a long lie (Farley et al, 2011), which according to the National Institute for Health and Care Excellence (NICE) (2013) is anything longer than 1 hour.
Falls prevention strategies from NHS Confederation and the Ambulance Service Network aim to keep people independent, which will impact positively on emotional and mental wellbeing (NHS Confederation, 2012). However, Age UK (2013) estimates that more than 250 000 people over the age of 65 fall each year. The NHS Confederation Report (2012) noted that falls account for 25–27% of all ambulance call-outs within the UK.
Of 13 ambulance services within the UK, on average 11 services leave 28.4% of elderly falls at home, including those who are defined as a ‘long lie’. The freedom of information (FOI) request issued in 2012 documented that two of the 13 trusts failed to respond, which indicates a much higher percentage of non-conveyed falls (Darnell et al, 2012). In numbers, this is a minimum of 71 000 people. This number is significant because not everyone will present with an obvious need to convey to hospital. It is evidenced rather widely that pre-hospital clinicians tend to focus on the cause of the fall and any obvious physical injury—particularly those associated with bones rather than the potential for muscular breakdown and secondary AKI (Criddle, 2003; Huerta-Alardín et al, 2005).
It is therefore reasonable to argue that with greater knowledge, training and recognition of rhabdomyolysis, the life-changing effects resulting from falls could be reduced.
Historical research
A group of researchers conducted a study into the prevalence of rhabdomyolysis in older people following a fall (Wongrakpanich et al, 2018). One-hundred and sixty-seven people over the age of 65 were admitted to hospital following a fall over a 4-year period, and had CK levels of greater than five times the normal parameters (Ratcliffe et al, 1984; El-Abdelatti et al, 2013).
There was a very small number of people enrolled into the study given that over 250 000 elderly people are hospitalised each year following a fall (Age UK, 2013). There are, however, limited studies which focus specifically on the prevalence of rhabdomyolysis in elderly falls within the UK. This study is one of the more highly regarded and cited despite only being published recently (Wongrakpanich et al, 2018).
One of the recommendations that came from the study suggested that it be indicated within UK pre-hospital guidelines to give up to 2 litres/hour of sodium chloride when rhabdomyolysis is suspected. This would improve chances of recovery and reduce the likelihood of developing AKI.
Conclusion
The review of current literature and guidelines acts as a prompt for further detailed study and clinical research into rhabdomyolysis in elderly fallers. Although there are many variable factors including comorbidities, length of lie and patients' age (Henderson, 2015), there remains a need for a greater focus on rhabdomyolysis—especially given that more than a quarter of ambulance call-outs relate to elderly falls.
With knowledge gained from training, and evidence obtained from research and clinical trials, there is a potential to further widen our capabilities to recognise rhabdomyolysis that results from other incidents such as illicit drug use, seizures and trauma.