<unk>  is an upper respiratory disease entailing swelling of the trachea caused by infection from human parainfluenza virus - an enveloped, single stranded negative sense RNA virus with four distinct serotypes. Development of viral<unk>  results from infiltration of histiocytes, lymphocytes, plasma cells, and neutrophils white blood cells primarily by human parainfluenza viruses (HPIV). The infiltration from HPIV causes inflammation by the up-regulated production of cytokines, localized in the trachea. HPIV-response Immunoglobulin E (IgE) release inhibits histamine, contributing to the inflammation of the trachea and leading to swelling of the larynx, trachea, and large bronchi that obstructs the airways, leading to<unk> . Known as "barking cough",<unk>  manifests through symptoms including a "bark-like" cough, stridor, hoarseness, respiratory distress, and common cold symptoms such as runny nose and low-grade fever.<unk>  symptoms typically manifest after 2-7 days of human parainfluenza virus infection, usually lasting between 24-48 hours with only rare instances reported of up to 7 days. They will typically resolve without treatment, excepting the most severe cases that pose the threat of respiratory failure.<unk>  must be differentiated from other upper respiratory diseases and conditions that cause airway obstruction around the larynx, as well as those that present similar symptoms to influenza.<unk>  is a very common disease and is almost always found in children between 6 months and 6 years of age, but rare cases have been reported in children as young as 3 months and as old as 15 years. Primary measures of preventing<unk>  involve preventing the spread of human parainfluenza virus. This is accomplished by maintaining personal hygiene, such as washing hands frequently, and limiting exposure to patients with<unk>  or other respiratory illness. Medical therapies to treat<unk>  are dependent on the classification of the particular case: mild, moderate, severe, and imminent respiratory failure. For mild<unk> , glucocorticoid therapy is usually sufficient to alleviate symptoms, typically administering nebulized dexmethasone and budesonide. For more severe cases, nebulized racemic and L-epinephrine is administered in conjunction with glucocorticoids. Hospitalization and intubation is very rare and is usually only used when the respiratory distress is life-threatening. Common physical examination findings of<unk>  are primarily chest and lung abnormalities. This includes inspiratory stridor, expiratory wheezing, suprasternal and intercostal indrawing, sternal wall retractions, and desynchronized chest and abdominal wall expansion. Low-grade fever can be present, as well as cyanosis in severe cases. Diagnosis of<unk>  is dependent on x-ray imaging of the chest and neck, with diagnostic images indicative of<unk>  including evidence of steeple sign: narrowing of the subglottic lumen in the neck. It also includes a visibly distended hypopharynx in some cases. Prognosis of<unk>  is usually good, with mild and moderate<unk>  usually resolving itself without treatment. Severe cases of<unk>  can have poor prognosis, if untreated, due to the possibility of respiratory failure. All classifications of<unk>  have good prognosis with appropriate treatment.
Croup
Tonsillitis
Laryngitis
Rhinosinusitis
Strep throat
Sinusitis
Sinusitis  
Epiglottitis