Pathophysiology of Pneumonia
Pneumonia is an infection in the lower respiratory tract that causes to inflammation of the lung parenchyma leading to a situation in which the alveoli, especially in the lobes, interstitial tissue, and bronchioles become edematous and filled with fluid.

Pneumonia begins with aspiration of organisms, either from the air when someone coughs or sneezes or via oropharyngeal secretions, into the lower respiratory tract. If the pathogen that enters the lungs overwhelms the alveolar macrophages the immune system is activated, leading to invasion of lung tissue by macrophages and other inflammatory mediators. This inflammatory process leads to decreased lung ventilation of the affected areas due to cellular infiltration and congestion. The filling of the alveoli with exudates or consolidation causes them to collapse. The resulting pneumonia can cause acute hypoxemia, which exacerbates such conditions as pulmonary hypertension and dilates the right ventricle, leading to cor pulmonale (Huether & McCance, 2008).

Pathophysiology of Cor Pulmonale
Cor pulmonale is also called pulmonary heart disease or right-sided heart failure. The pathophysiology of cor pulmonale is linked to left-sided heart failure. “Right heart failure can result from left heart failure when an increase in left ventricular filling pressure is reflected back into the pulmonary circulation. As pressure in the pulmonary circulation rises, the resistance to right ventricular emptying increases. The right ventricle is poorly prepared to compensate for this increased afterload and will dilate and fail” (Huether & McCance, p656, 2008).

Pathophysiology of Type 2 Diabetes Mellitus
Diabetes mellitus type 2 (DMT2) involves a complex pathophysiology resulting in insulin resistance or decreased beta cell responsiveness or both. Normally, insulin is secreted when levels of glucose in the blood increase. Insulin secretion diminishes in response to low blood levels of glucose (Ibid, 2008). DMT2 occurs when there is cellular resistance to the action of insulin. This leads to increased levels of glucose in the blood, causing a variety of complications within the body.
One of these complications is immunosuppression (Vardakas, Siempos, & Falagas, p1168, 2007). As a result, the diabetic is prone to diseases such as pneumonia. In addition, DMT2 has several adverse effects on the cardiovascular system “including endothelial damage, thickening of the vessel wall, increased inflammation… and decreased production of endothelial-derived vasodilators such as nitric oxide. Diabetes is also associated with dyslipidemia” (Huether & McCance, p624, 2008).

These conditions are all associated with hypertension, which can lead to left-ventricular hypertrophy (Ibid, p611, 2008) and/ or failure and ultimately right-sided heart failure (cor-pulmonale) (Ibid, p655, 2008).