From the Guidelines
Pneumonia can develop within 1-14 days after infection, with a median incubation time of 5.2 days, as estimated by the World Health Organisation (WHO) 1. The development of pneumonia is influenced by various factors, including the type of infectious agent, the person's immune status, age, and underlying health conditions.
- The stages of the disease from onset of symptoms can be divided into early (0–4 days), progressive (5–8 days), peak (9–13 days), and absorption stages (≥14 days) 1.
- The early stage disease consists of subpleural ground glass opacities (GGO) located in the lower lung lobes, while the progressive stage demonstrates bilateral distribution of the infective process and diffuse GGO 1.
- The presence of dense consolidation, crazy-paving pattern and residual parenchymal bands indicates transition into the peak stage, and the absorption stages may last more than 26 days, with a better controlled disease process on CT, gradual resolution, and signs of recovery 1. It is essential to seek medical attention promptly when experiencing persistent cough, fever, and breathing difficulties for early diagnosis and treatment.
- The mean time from presentation of symptoms to seeking medical advice is 5.8 days, and to hospital admission is 12.5 days 1.
- The incubation time and the speed of development can vary significantly, and it is crucial to consider these factors when assessing and managing patients with pneumonia.
From the Research
Development of Pneumonia
- The development of pneumonia largely depends on the host immune response, with pathogen characteristics having a less prominent role 2.
- Pneumonia can occur more commonly in susceptible individuals, including children of <5 years of age and older adults with prior chronic conditions 2.
- The time it takes for pneumonia to develop is not explicitly stated in the provided studies, but the development of the disease is influenced by various factors such as the host immune response and pathogen characteristics.
Symptoms and Diagnosis
- Individuals with pneumonia often present with respiratory and systemic symptoms, and diagnosis is based on both clinical presentation and radiological findings 2.
- A new infiltrate on imaging in a patient with symptoms and signs of pneumonia is used to diagnose community-acquired pneumonia (CAP) 3.
- The diagnosis and treatment of pneumonia should be based on the results of diagnostic studies to allow pathogen-directed therapy and optimal antimicrobial stewardship 3.
Treatment and Duration
- The recommended duration for antimicrobial therapy is 3 to 5 days if there is good clinical improvement by day 2 or 3 3.
- Procalcitonin levels can be useful as an adjunct to clinical judgment for determining the appropriate duration of therapy 3.
- Azithromycin 1g once daily for 3 days is at least as effective as amoxicillin-clavulanate 875/125 mg twice daily for 7 days in the treatment of adult patients with community-acquired pneumonia 4.