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The Role of the Occult Infection in Falls

Amesh A. Adalja, MD, FACP, FACEP, FIDSA, October 16, 2015

The concept of occult infection is one known to many frontline clinicians and is considered in various settings when an infection may be responsible for a seemingly unrelated condition. Earlier this month, at IDWeek 2015, Blair and Manian from Massachusetts General Hospital demonstrated occult infection in a remarkably high percentage of adults who presented to their emergency department subsequent to falls.1


Infections Not Initially Suspected

In this retrospective study, 161 patients who had fallen, who presented to the emergency department, and who were subsequently admitted were found to have an infection. Of those with confirmed infections, no infection had initially been suspected in 41%. Not surprisingly, urinary tract infections were the most common infection detected; however, nearly 40% of the 161 with infections had a bloodstream infection. The majority of infections were truly occult in that 56% of patients exhibited no criteria or only 1 criterion consistent with a systemic inflammatory response syndrome (SIRS). Only 20% had fever.1

The age of the included patients ranged from 35 to 102, with fully 20% under the age of 65. Staphylococcus aureus and Escherichia coli were the 2 most common bloodstream isolates detected.1


Moving Beyond the Usual Algorithms

While the study has some limitations—it is retrospective and was conducted at a single center—it has important implications. Falls are a major source of morbidity and mortality, especially in elderly patients. Pinpointing the exact inciting and co-present conditions for a fall can be difficult, and clinical algorithms often involve metabolic, cardiovascular, and neurologic testing in looking for a mechanical cause or obvious infection. However, this study demonstrates that occult infection must also be considered.

Bloodstream infections require prompt recognition and treatment in order to forestall often severe complications. The cornerstone of this approach is early detection. The fact that the majority of infected patients in this study did not demonstrate 2 SIRS criteria is more evidence that relying on SIRS alone to find septic patients is not optimal.2

While it is unclear from this preliminary study if infection was the true inciting event for falls, addressing the possibility of occult infection should likely become a routine part of the clinical care of such patients. Further studies are needed to replicate and refine these important findings.



  1. Blair AJ, et al. Coexisting systemic infections (CSIs) in patients presenting with a fall: tripped by objects or pathogens? Abstract 813. Presented at: IDWeek; Oct. 7-11, 2015; San Diego
  2. Kaukonen K, Bailey M, Pilcher D, et al. Systemic inflammatory response syndrome in defining severe sepsis. N Engl J Med 2015;372:1629-1638.