Posted: June 6th, 2021

Case Study: Infection in the Elderly

Case Study: Infection in the Elderly

As people age, their immune systems gradually weaken, making them more susceptible to infections (Aspinall & Del Giudice, 2019). This case study examines 72-year-old Frank, who presented to his general practitioner (GP) with signs and symptoms of infection following a gardening injury. By exploring Frank’s scenario through the lens of relevant anatomy, physiology and epidemiological concepts, we can gain insight into infection risk and prevention in the elderly population.
Lines of Defence and Immune Response
The human body employs three lines of defence against infection: physical barriers, innate response, and adaptive immunity (Kumar et al., 2017). Frank’s first line of defence, the skin, was breached when he cut his palm without gloves while gardening. Instead of immediately cleaning the wound, he continued working, allowing pathogens entry (Centers for Disease Control and Prevention [CDC], 2021).
Signs of inflammation in Frank’s hand, including swelling, redness and pain, indicate activation of the innate immune response – the body’s second line of defence (Kumar et al., 2017). Phagocytic white blood cells like neutrophils migrate to the site of injury, where they engulf and destroy pathogens (Janeway et al., 2001). Frank’s fever and elevated white blood cell count are further signs the innate response is fighting the infection (Kumar et al., 2017).
The swollen lymph node in Frank’s armpit suggests involvement of his adaptive immune system – lymphocytes that develop pathogen-specific responses (Kumar et al., 2017). Lymph nodes filter lymph fluid, trapping bacteria and alerting B and T cells (Janeway et al., 2001). Together, these immune defenses demonstrate how the body normally protects against infection.
Chain of Infection and Prevention Measures
For an infection to occur, several factors must align in what is known as the “chain of infection” (CDC, 2021). In Frank’s case, his cut hand provided a portal of entry. Wearing gloves could have prevented injury and maintained skin integrity. Promptly cleaning the wound may have flushed out pathogens before replication (Janeway et al., 2001). Frank’s GP also prescribed antibiotics, targeting the causal bacterial agent and eliminating it from the chain (Kumar et al., 2017). With minor alterations to hygiene practices, Frank may have avoided infection.
Homeostasis and Thermoregulation

Homeostasis refers to the body’s ability to maintain stable internal conditions despite external changes (Kumar et al., 2017). When Frank became overheated at the bus stop, thermoreceptors detected the rise in core temperature. Through negative feedback, the brain signaled sweat glands to secrete sweat and cool the body via evaporation (Tortora & Derrickson, 2014). This feedback loop exemplifies how homeostasis supports physiological stability.
Conclusion
By applying knowledge of relevant anatomy, physiology and epidemiology concepts to Frank’s case, we have gained insight into infection risk and prevention in the elderly. Minor adjustments to hygiene practices, like wearing gloves and promptly cleaning wounds, can maintain the skin’s protective barrier. Understanding how the immune system and homeostasis normally function also provides context for Frank’s presentation. With aging, even minor insults may overwhelm declining defenses, highlighting the importance of infection control measures in this population.
References
Aspinall, R., & Del Giudice, G. (2019). Understanding the immune system of the elderly: A key to optimizing health in later life. Translational Medicine of Aging, 3, 1-6. https://doi.org/10.1016/j.tma.2019.03.001
Centers for Disease Control and Prevention. (2021, February 11). Principles of epidemiology in public health practice: An introduction to applied epidemiology and biostatistics. https://www.cdc.gov/csels/dsepd/ss1978/lesson1/section11.html
Janeway, C. A., Travers, P., Walport, M., & Shlomchik, M. J. (2001). Immunobiology: The immune system in health and disease (5th ed.). Garland Science.
Kumar, V., Abbas, A. K., Aster, J. C., & Perkins, J. A. (2017). Robbins basic pathology (10th ed.). Elsevier.
Tortora, G. J., & Derrickson, B. (2014). Principles of anatomy and physiology (14th ed.). John Wiley & Sons.

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