Who killed Bruce Lee? The hyponatraemia hypothesis

Abstract

Bruce Lee brought attention to martial arts in the Western world and popularized the quote 'Be water, my friend'. Lee died at the age of 32 years in Hong Kong on 20 July 1973, under mysterious circumstances. The cause of death is unknown, although numerous hypotheses have been proposed, from assassination by gangsters to the more recent suggestion in 2018 that he died from heatstroke. The necropsy showed cerebral oedema. A prior episode was diagnosed as cerebral oedema 2 months earlier. We now propose, based on an analysis of publicly available information, that the cause of death was cerebral oedema due to hyponatraemia. In other words, we propose that the kidney's inability to excrete excess water killed Bruce Lee. In this regard, Lee had multiple risk factors for hyponatraemia that may have included high chronic fluid intake, factors that acutely increase thirst (marijuana) and factors that decrease the ability of the kidneys to excrete water by either promoting secretion of antidiuretic hormone (ADH) or interfering with water excretion mechanisms in kidney tubules: prescription drugs (diuretics, non-steroidal anti-inflammatory drugs, opioids, antiepileptic drugs), alcohol, chronic low solute intake, a past history of acute kidney injury and exercise.

Keywords: Bruce Lee death; SIADH; cannabis; cerebral oedema; diuretics; heatstroke; hyponatraemia; low osmolar intake; opioids.

FIGURE 1:

Water balance homeostasis and Bruce Lee's risk factors for hyponatraemia. Hypernatraemia means that there is a deficiency in extracellular water and the body adapts by increasing water intake through thirst and decreasing water loss in urine by secreting antidiuretic hormone (ADH), which results in more a concentrated, lower amount of urine (A). If hyponatraemia develops, these mechanisms will be shut down, resulting in an increased volume of more dilute urine (B). Severe hyponatraemia may result from failure to timely shut down mechanisms that increase water intake and decrease water excretion once hyponatraemia has developed (C). Severe hyponatraemia may trigger cerebral oedema and herniation through the foramen magnum in the occipital bone of the skull, resulting in death within hours. Green arrows indicate adaptive mechanisms. Red arrows indicate mechanisms that are inappropriately activated and not in line with physiological needs to maintain water homeostasis. Lee had several risk factors for severe hyponatraemia that interfered with all levels of control of water balance, from thirst to ADH secretion to ADH action in the kidneys to decrease water excretion in urine.

FIGURE 2:

Prescription drugs and risk for hyponatraemia. A higher number of prescription drugs associated with hyponatraemia further increases the risk of hyponatraemia in patients with other predisposing factors. Bar graph built using data from reference [31].