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Pathophysiology of Pneumonia

Pathophysiologyof Pneumonia

Pathophysiologyof Pneumonia

Pneumonia is an infection thatinterferes with one or both of the lungs. The condition is caused byeither bacteria or viruses. After one has been infected, the air sacsor alveoli within the lungs become inflamed (Choi, 2012). Also, pusand other fluids fill the alveoli, making it hard for the victim tobreathe. Pneumonia has several symptoms which can be mild or severe(van den, 2012). Generally, as a result of infection, the lungs of aninfected person swell, become less spongy, and the two sides getintact. The primary symptoms of pneumonia include coughs withgreenish or yellow mucus, fever, chills, and breath shortness (Bosch,2013). Fortunately, there are vaccines that prevent one from gettingpneumonia. The paper explores the different types of pneumonia, theircausative agents, as well as clinical signs and diagnostic resultswith regards to bacterial and viral origins.

Differenttypes (their pathophysiology in terms of usual causative agents)

The first type is bacterialpneumonia which tends to affect anyone regardless of age. It developsnaturally or after an attack by flu. This type of pneumonia isusually caused by Streptococcus pneumonae, Chlamydophila pneumonia,or Legionella pneumophila (Bosch, 2013). Bacteria invade the mucousmembrane on the surface of the internal lungs leading to instantinflammation. Invasion prompts the immune system to send white bloodcells to the affected areas. Neutrophils then react with and kill thewhite blood cells resulting to fever and fatigue (Bosch, 2013). Casesof bacterial pneumonia can be mild or severe depending on the levelsof bacterial strain.

Secondly, there is viralpneumonia which is caused by respiratory viruses. When one isattacked by flu, the viruses get to the linings of the alveoli,leading to cell destruction through apoptosis. The immune systemresponds to the infection, hence further damage happens to the lungs.In some cases, viral pneumonia occurs as a result of chickenpox oradenoviruses (van den, 2012). In these instances, one gets it byinhaling infected coughs or being in contact with a contaminatedobject. After contamination, respiratory viruses multiply in theupper airways of the epithelium. Mechanism of tissue damage dependson the virus that is involved (Bosch, 2013). However, when theviruses are majorly cytopathic, they affect pneumocytes directlyleading to severe cases of viral pneumonia.

Third, there is mycoplasmapneumonia which is caused by mycoplasma organisms the smallestdisease agents. They cause pneumonia because of their easy movementthrough respiratory fluids. The infection involves both upper andlower respiratory tracts. The last and the rarest type is fungalpneumonia which is caused by fungi. The opportunistic virus is theleading cause of this type of pneumonia (van den, 2012). The fungimay be in the form of blastomycosis, coccidioidomycosis, orhistoplasmosis. They mostly reach the lung as a result of inhalation.However, they can also reach the lungs through the blood stream whenanother part of the body is infected. The fungi move in the spacesbetween alveoli (Bosch, 2013). The movement makes the immune systemto respond. The white blood cells attack neutrophils which in turnkills the fungi, leading to chills, fever, and fatigue (van den,2012).


Clinical manifestation ofbacterial pneumonia varies from one person to another, but thesymptoms at the onset include coughs with sputum and consistentillnesses. Additionally, a patient with bacterial infection hashigher chances of suffering from chest pain and rigors (Prince,2013). Mycoplasma pneumonia is usually mild, and most adult cases areasymptomatic. However, its manifestations are similar to those ofbacterial pneumonia. Typical clinical features of mycoplasmapneumonia include sore throat and pain in the joints (Bosch, 2013).In addition, a patient may suffer from constant coughs during the dayand night. In a case of persistent coughs, there is a highprobability that the infection has extended to the lower parts of theairways (van den, 2012). In children, mycoplasma pneumonia mostlymanifests through wheezing chest, especially during morning hours.

The clinical manifestations ofviral pneumonia also vary as a result of seasonal characteristics. Inother words, viral infections are more expected to occur duringspecific times of the year (Choi, 2012). Nonetheless, the most commonexpressions of viral pneumonia include fever, chills, fatigue, andheadache. Elderly patients who are affected by the condition tend toexperience persistent coughs. In the case of fungal pneumonia, apatient experiences persistent fevers and dry coughs (Bosch, 2013).The other way through which fungal infection manifests is throughdiscomfort in the chest and difficulty in breathing. If the conditionworsens, a patient may experience secondary symptoms, especiallyweight loss and constant fevers.

DiagnosticFindings (differences between viral and bacterial origins)

According to diagnosticfindings, the most notable difference between bacterial and viralpneumonia is that the former can be curbed by antibiotic drugs, butthe medications may not be effective in the case of the former(Bosch, 2013). Additionally, diagnostic results show that clinicalsigns and blood leukocytes are not effective in determining bacterialpneumonia, but may be used to detect viral cases. Diagnosis of viralpneumonia may be conducted by chest examinations, while the mostpreferred strategy for bacterial pneumonia is serological methods.When the two cases are compared, it is revealed that symptoms ofbacterial infection vary more than those of viral infection (van den,2012).

To conclude, pneumonia is aninfection of the lung that has various causes. Symptoms depend on thetype of infection. Viral and bacterial pneumonia portray almostsimilar symptoms. Clinical manifestos can show the form of pneumoniaa patient is suffering. The diagnosis helps determine the stage ofillness, whether mild or severe. Early detection of the disease ishelpful as it saves one from the severe secondary stages.


Bosch,A. A., (2013). Viraland Bacterial Interactions in the Upper Respiratory Tract.PLoS Pathog, 9(1),

Choi,S. (2012). Viralinfection in Patients with Severe Pneumonia Requiring Intensive Care Unit Admission.American Journal of Respiratory and Critical Care Medicine, 186(4), 325-332.

vanden. B., (2012). Associations between Pathogens in the UpperRespiratory Tract of Young Children: Interplaybetween Viruses and Bacteria.PLoS One, 7(10), e47711.

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