Medical complications associated with earthquakes

Summary

Major earthquakes are some of the most devastating natural disasters. The epidemiology of earthquake-related injuries and mortality is unique for these disasters. Because earthquakes frequently affect populous urban areas with poor structural standards, they often result in high death rates and mass casualties with many traumatic injuries. These injuries are highly mechanical and often multisystem, requiring intensive curative medical and surgical care at a time when the local and regional medical response capacities have been at least partly disrupted. Many patients surviving blunt and penetrating trauma and crush injuries have subsequent complications that lead to additional morbidity and mortality. Here, we review and summarise earthquake-induced injuries and medical complications affecting major organ systems.

Introduction

Earthquakes are some of the most catastrophic natural disasters to affect mankind. The structural damage resulting from severe earthquakes causes many deaths and traumatic injuries in a short period without advanced warning.¹ More than a million earthquakes occur worldwide every year, which equates to roughly two earthquakes per minute.² In the past decade alone, disasters have caused more than 780 000 deaths, with earthquakes accounting for nearly 60% of all disaster-related mortality (table 1).⁴ In addition to these deaths, earthquakes have directly affected another 2 billion people in this period.² The threat of earthquakes will probably increase because of global urbanisation and the vulnerability of large urban centres. Many of the most populous cities in the world are on fault lines, and thus millions of people are exposed to earthquakes (figure 1, table 2).⁴

The epidemiology of mortality and injury means that earthquakes can be differentiated from other natural hazards, such as hurricanes and flood emergencies. Floods and hurricanes typically cause many deaths due to drowning but few serious medical or surgical injuries. As such, these other disasters do not usually overload the existing curative medical system. By comparison, earthquakes not only cause many deaths initially, but also many severe injuries requiring complex surgical and resuscitative medical care. By destroying medical facilities, roads, and bridges, in addition to interrupting medical supply chains, earthquakes devastate the local curative medical capacity and create a large, unmet need for complex surgical and medical care.

The morbidity and mortality caused by an individual earthquake is dependent on magnitude, epicentre's proximity to large urban centres, degree of earthquake preparedness, and extent to which mitigation measures have been implemented.² Massive earthquakes can result in casualty rates ranging from 1% to 8% of the at-risk population.⁷ The reported ratios of death to injury vary, but across many studies seem to be about 1:3.⁸

Fatalities that result from catastrophic injuries at the time of the earthquake are immediate deaths.⁹ Severe trauma of the brain or spinal cord is a common cause of such injuries and these patients are generally not saveable. Other earthquake victims perish quickly within the first several hours after the event, and past experience has suggested that mortality could be reduced greatly if prompt treatment is provided.¹⁰ These individuals have injuries such as subdural haematomas, liver or spleen lacerations, and pelvic fractures. Finally, a third peak of deaths occurs days to weeks after the earthquake and is attributable to sepsis, multisystem organ failure, and disseminated intravascular coagulation.¹¹ These patients die more slowly from injury complications and have the greatest savable potential.9, 11

Injured victims usually seek emergency medical care in the first 3–5 days after an earthquake.² Thus, the greatest demand for health-care providers comes within the first week. Although primary-care complaints do increase in frequency beyond the first week, care of acutely injured victims might continue to predominate for several weeks, especially when there are large numbers of casualties or when the health-care infrastructure has been destroyed. The arrival of health-care responders, medical equipment, and supplies after this initial period is still important because it helps to reinstate the prehospital-care system, to treat delayed complications, to manage less acute injuries, and to resume management of chronic illnesses and endemic diseases.

Understanding of the medical effects of earthquakes, especially in large urban centres, necessitates awareness of the regional seismic risk, structural vulnerability, local response capacity, and resilience of the curative medical services. A multidisciplinary approach is needed to create a mechanism for prevention, search and rescue, and medical response. In this Review, we discuss the acute medical complications of earthquake-related injuries to major organ systems. Chronic disorders, such as diabetes, heart disease, and asthma, might worsen after earthquakes. These exacerbations could be secondary to earthquake-related trauma, disruption of the health-care system, or an interruption in the patients' ability to self-manage because of earthquake-induced loss of medications, medical equipment, or medical supplies. Although important, discussion of these pre-existing medical conditions and the exacerbations related to earthquakes is not considered in this Review.