In cases of decreased or total loss of consciousness, the tongue can lose muscle tone and obstruct the upper airway. Other potential causes of obstruction include tumors of the upper respiratory tract (oral cavity, pharynx, larynx), bodily fluids (blood, mucus, vomit), and trauma to the upper airway. The most common type of tumor of upper respiratory tract is squamous cell carcinoma, with the greatest risk factors for this condition being alcohol and tobacco use, with HPV (genotype 16) being another important risk factor. An epidemiological study of over 5 million cases of head and neck trauma in the United States resulting in visits to the emergency department found that the majority occur due to falls or blunt force, with foreign body injuries being more common in the pediatric population. Lower airway: may occur from bronchospasm, drowning, or airspace filling disorders (e.g. pneumonia, pulmonary edema, pulmonary hemorrhage). Obstructive conditions of the lower airway, including severe asthma or COPD episodes, can also lead to respiratory arrest. During these episodes, known as exacerbations, airway resistance is increased due to inflammatory changes in the lungs. This leads to increased work of breathing and decreased oxygen delivery to tissue. In asthma, this involves bronchiolar constriction whereas in COPD this involves small airway collapse during expiration and subsequent air-trapping. One of the ways the body attempts to compensate for these increased respiratory demands is by increasing respiratory rate, which in turn worsens respiratory muscle fatigue of the diaphragm and can eventually lead to respiratory arrest and death without timely medical intervention.
Pigmented purpuric dermatosis refers to one of the three major classes of skin conditions characterized by purpuric skin eruptions. Pigmented purpuric dermatosis are distinguished from other purpura by size (0.3–1 cm) and are most often seen in the lower extremities. : 829   Pigmentary purpuric eruptions may present with one of several clinical patterns. There may be overlapping characteristics among pigmented purpuric dermatosis and between their signs and those of other purpuric eruptions. : 829   Examples of the pigmented purpuric dermatosis group include:: 829–30 
Schambergs disease
Majocchis disease (Purpura annularis telangiectodes)
Gougerot-Blum syndrome (Pigmented purpuric lichenoid dermatitis)
Ducas and Kapetanakis pigmented purpura
Lichen aureusAlthough vascular damage may be present, it is insufficient for these conditions to be considered forms of vasculitis.A few very small non-blinded studies of treatment with narrow-band ultraviolet light have been reported as promising. See also
Purpura
Skin lesion
List of cutaneous conditions

References


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