Nitrogen dioxide is a deep lung irritant that can produce pulmonary edema and fatality if inhaled at high concentrations. The effects of NO2 depend on
the level and duration of exposure. Exposure to moderate NO2 levels (50 ppm) may produce cough, hemoptysis, dyspnea, and chest pain. Exposure to
higher concentrations of NO2 (>100 ppm) can produce pulmonary edema that may be fatal or may lead to bronchiolitis obliterans. Some studies suggest
that chronic exposure to nitrogen dioxide may predispose individuals to the development of chronic lung diseases, including infection and chronic
obstructive pulmonary diseases.
* Acute exposure - Symptoms may range from mild cough to mucous membrane irritation to sudden fatality.
o Suspect methemoglobin in patients exposed to nitrogen dioxide gas who exhibit cyanosis or dyspnea.
o The initial absence of significant symptoms does not exclude a subsequent development of serious disease.
* Latency period - Following a delay of 2-48 hours, patients exposed to nitrogen dioxide may develop the following symptoms:
o Dyspnea
o Cough
o Chest pain
o Clinical manifestations of noncardiogenic pulmonary edema
* Late sequelae - The following may develop 2-6 weeks after initial nitrogen dioxide exposure:
o Bronchiolitis obliterans, manifested as fever, cough, and dyspnea
o Diffuse reticulonodular or miliary pattern on chest x-ray
Physical: Initial physical findings are sometimes mild but may progress over the following 72 hours to life-threatening respiratory distress.
* Pulmonary symptoms are the most common manifestation of nitrogen dioxide toxicity.
o Cough
o Dyspnea
o Chest tightness
o Choking
o Wheezing
o Chest pain
o Rales
o Rhonchi
o Decreased breath sounds
o Stridor
* Other acute symptoms
o Light-headedness
o Loss of consciousness
o Restlessness
o Agitation
o Confusion
o Irritation of mucous membranes, including the eyes
o Conjunctival infection
o Weakness
o Fatigue
o Nausea
o Abdominal pain
o Skin burns, in cases of liquid nitrogen tetroxide exposure
* Delayed symptoms
o Tachypnea
o Headache
o Fever, chills
o Insomnia
o Myalgias
o Hemoptysis
o Palpitations
o Cyanosis
o Coma
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Go figure!
