Increased conduit vessel stiffness results in increased characteristic impedance of the aorta and decreased arterial compliance, which cause an increase in systolic blood pressure (SBP) and pulse pressure as well as a decrease in diastolic blood pressure (DBP).
Local trauma is the most common cause, followed by facial trauma, foreign bodies, nasal or sinus infections, and prolonged inhalation of dry air. Children usually present with epistaxis due to local irritation or recent upper respiratory infection (URI).
These organisms constitute the normal flora of the respiratory tract. The nasal flora is restricted to the most proximal region of the conducting system (nasal cavity, the pharynx, larynx and trachea). The distal portions of the respiratory tract, bronchioles and alveoli are considered to be essentially sterile.