Pathophysiology
Neuroendocrinology
PTSD symptoms may result when a traumatic event causes an over-reactive adrenaline response, which creates deep neurological patterns in the brain. These patterns can persist long after the event that triggered the fear, making an individual hyper-responsive to future fearful situations. During traumatic experiences, the high levels of stress hormones secreted suppress hypothalamic activity that may be a major factor toward the development of PTSD.PTSD causes biochemical changes in the brain and body, that differ from other psychiatric disorders such as major depression. Individuals diagnosed with PTSD respond more strongly to a dexamethasone suppression test than individuals diagnosed with clinical depression.Most people with PTSD show a low secretion of cortisol and high secretion of catecholamines in urine, with a norepinephrine/cortisol ratio consequently higher than comparable non-diagnosed individuals. This is in contrast to the normative fight-or-flight response, in which both catecholamine and cortisol levels are elevated after exposure to a stressor.Brain catecholamine levels are high, and corticotropin-releasing factor (CRF) concentrations are high. Together, these findings suggest abnormality in the hypothalamic-pituitary-adrenal (HPA) axis. The maintenance of fear has been shown to include the HPA axis, the locus coeruleus-noradrenergic systems, and the connections between the limbic system and frontal cortex. The HPA axis that coordinates the hormonal response to stress, which activates the LC-noradrenergic system, is implicated in the over-consolidation of memories that occurs in the aftermath of trauma. This over-consolidation increases the likelihood of ones developing PTSD.
Bronchopneumonia is a subtype of pneumonia. It is the acute inflammation of the bronchi, accompanied by inflamed patches in the nearby lobules of the lungs.It is often contrasted with lobar pneumonia; but, in clinical practice, the types are difficult to apply, as the patterns usually overlap. Bronchopneumonia (lobular) often leads to lobar pneumonia as the infection progresses. The same organism may cause one type of pneumonia in one patient, and another in a different patient. Causes
Bronchopneumonia is usually a bacterial pneumonia rather than being caused by viral disease.It is more commonly a hospital-acquired pneumonia than a community-acquired pneumonia, in contrast to lobar pneumonia.Bronchopneumonia is less likely than lobar pneumonia to be associated with Streptococcus pneumoniae. Rather, the bronchopneumonia pattern has been associated mainly with the following: Staphylococcus aureus, Klebsiella, E. coli and Pseudomonas. Pathology
Bronchopneumonia may sometimes be diagnosed after death, during autopsy. On gross pathology there are typically multiple foci of consolidation present in the basal lobes of the human lung, often bilateral. These lesions are 2–4 cm in diameter, grey-yellow, dry, often centered on a bronchiole, poorly delimited, and with the tendency to confluence, especially in children. Light microscopy typically shows neutrophils in bronchi, bronchioles and adjacent alveolar spaces. Treatment
Compared to pneumonia in general, the association between the bronchopneumonia pattern and hospital-acquired pneumonia warrants greater consideration of multiple drug resistance in the choice of antibiotics. See also
Lobar pneumonia


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