Aetiology And Pathophysiology Of Bacterial Pneumonia

Aetiology of Bacterial Pneumonia

Discuss about the Pneumonia for Aetiology and Pathophysiology.

The inflammation of alveoli in the lungs is known as Pneumonia. Breathing problem associated with cough, high fever, lethargy, and feeling of light headedness is common. The most common cause of pneumonia during pregnancy is Community acquired pneumonia. CAP is responsible for many deaths in the Asian continent (Lozano et al, 2010). The main causal organisms of community acquired pneumonia are bacteria like streptococcus pneumonia, staphylococcus aureus, mycoplasma pneumonia, heamophilus influenza and chlamydophila pneumoniae ¸legionella pneumoniae, etc.

Gram positive bacteria responsible for causing pneumonia includes mainly Streptococcus pneumoniae-it is one of the most common causal organisms of pneumonia. (Peto et al, 2014). It is a gram positive facultative anaerobe. It resides in the nasopharynx and affects the respiratory tract, nasal cavity and sinuses in case of infection. The major risk of infection is for older people and people with chronic infection. Severe infection could lead to upper respiratory disorders.Staphylococcus aureus mainly infect the drug abusers or patients with deliberate disease and chronic diseases. The infection makes it way to the lungs through blood.Legionella pneumophilla is present mainly in warm and still water and infects in summer. It could be present in air conditioning systems and contaminated water system.

Gram negative bacteria infect people who have immunodeficiency or those who get hospitalized.  Previous antibiotic treatment is also a major factor. Klebsiella pneumoniae infect people suffering from diabetes, COPD or those who are alcoholic. (Musher, D. M. and Thorner, A. R., 2012, Oct 23). Haemophilus influenza infects mainly in winter infecting the upper respiratory tract. (Porth and Bruyere, H J., 2009). Patients having COPD, with low immunity asthma or deliberate diseases are mainly at risk.

 Normally bacteria are present in the respiratory tract. To cause pneumonia the bacteria show high growth rate, low immunity or presence of virulent forms of the organism. The pathogenic bacteria make it way to the alveoli lung infection. Low immunity is also a major factor for the infection. The alveolar macrophages fail to act against the virulent pathogens causing a severe infection. Some bacteria get adhered to the tracheal lining making it difficult to clear them off. (Porth and Bruyere, H. J., 2009).

Bacteria may show high virulence rate due to development of resistance to the common antibiotics. Mutative form with a better resistance can create difficulty in treatment. Bacterial flagella and cilia helps in the movement of the bacteria, thus spreading the infection becomes easy for the pathogen. Presence of spore or capsules gives advantages to the bacteria to be resistant against the immune system of the person. (Kamangar, N. 2015, Oct 8). Inflammation in the lower respiratory tract occurs on the proliferation of the infection. The immune cells causing the inflammation start accumulating in the alveoli and fill the air sac with pus which affects the respiration

The possible reasons for a person to acquire the disease include the respiratory route where the pathogen is inhaled from the contaminated surroundings. It could be contagious, spreading from an infected person to those who come in contact. Also in the drug abuser the route is through blood supply system. Age, mal nourishment, smoking or due to other chronic diseases, immunosuppressing disease like HIV adds to the infection.

References

Lozano, R et al. 2013. Global and regional mortality from235 causes of death for 20 age groups in 1990 and 2010: a systemic analysis for the Global Burden of Disease Study 2010. Lancet; 380:2095-128. Retrieved on 19 Sep 2016.

Peto et al. (2014). The bacterial aetiology of adult community- acquired pneumonia in Asia: a systematic review. Transaction of the royal society of tropical medicine & hygiene. Vol 108, issue 6. 326-337. Doi:10.1093/trstmh/tru058.

Kamangar, N. (2015). Bacterial pneumonia. Medscape.Viewed on 19 September 2016 from https://emedicine.medscape.com/article/300157Porth, C, M, Bruyere, H, J. (2009). Bacterial pneumonia. Porth: Pathophysiology 8^th Ed +Bruyere: 100 case studies in pathophysiology. USA: Lippincott Williams & Wilkins.

Musher, D.M. and Thorner, A. R. (2014, Oct 23). Community acquired pneumonia. The New England Journal of Medicine. 371:1619. Doi: 10. 1056/NEJMra1312885. Retrieved on 19 Sep 2016.