Pneumonia severity index

Pneumonia Severity Index (PSI) is a clinical prediction rule that medical practitioners use to calculate the probability of morbidity and mortality among patients with community-acquired pneumonia. This index helps in the management of patients by identifying those who may require hospitalization or intensive care.

Overview[edit | edit source]

The Pneumonia Severity Index was developed by Fine MJ et al. in 1997. It uses a combination of patient's age, co-morbid illness, physical examination findings, and laboratory and radiographic findings to categorize patients into five risk classes. These classes predict the risk of short-term mortality and other adverse outcomes.

Calculation[edit | edit source]

The PSI score is calculated based on 20 variables. These variables include demographic factors, co-morbid illnesses, physical examination findings, and laboratory and radiographic findings. Each variable is assigned a point value, and the total score determines the patient's risk class.

Risk Classes[edit | edit source]

The PSI divides patients into five risk classes:

Class I: Very low risk of mortality. Outpatient care is usually sufficient.
Class II: Low risk of mortality. Outpatient care or observation is usually sufficient.
Class III: Moderate risk of mortality. Short inpatient hospitalization or closely monitored outpatient care is recommended.
Class IV: High risk of mortality. Inpatient hospitalization is recommended.
Class V: Very high risk of mortality. Consideration for intensive care is recommended.

Limitations[edit | edit source]

While the PSI is a useful tool, it has some limitations. It may underestimate the severity of illness in younger patients with few comorbidities. It also does not consider the social factors that may affect a patient's ability to receive outpatient treatment.