Croup in the context of "Respiratory infection"

Diphtheria is an infection caused by the bacterium Corynebacterium diphtheriae. Most infections are asymptomatic or have a mild clinical course, but in some outbreaks, the mortality rate approaches 10%. Signs and symptoms may vary from mild to severe, and usually start two to five days after exposure. Symptoms often develop gradually, beginning with a sore throat and fever. In severe cases, a grey or white patch develops in the throat, which can block the airway, and create a barking cough similar to what is observed in croup. The neck may also swell, in part due to the enlargement of the facial lymph nodes. Diphtheria can also involve the skin, eyes, or genitals, and can cause complications, including myocarditis (which in itself can result in an abnormal heart rate), inflammation of nerves (which can result in paralysis), kidney problems, and bleeding problems due to low levels of platelets.

Diphtheria is usually spread between people by direct contact, through the air, or through contact with contaminated objects. Asymptomatic transmission and chronic infection are also possible. Different strains of C. diphtheriae are the main cause in the variability of lethality, as the lethality and symptoms themselves are caused by the exotoxin produced by the bacteria. Diagnosis can often be made based on the appearance of the throat with confirmation by microbiological culture. Previous infection may not protect against reinfection.

The trachea (pl.: tracheae or tracheas), also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all animals' lungs. The trachea extends from the larynx and branches into the two primary bronchi. At the top of the trachea, the cricoid cartilage attaches it to the larynx. The trachea is formed by a number of horseshoe-shaped rings, joined together vertically by overlying ligaments, and by the trachealis muscle at their ends. The epiglottis closes the opening to the larynx during swallowing.

The trachea begins to form in the second month of embryo development, becoming longer and more fixed in its position over time. Its epithelium is lined with column-shaped cells that have hair-like extensions called cilia, with scattered goblet cells that produce protective mucins. The trachea can be affected by inflammation or infection, usually as a result of a viral illness affecting other parts of the respiratory tract, such as the larynx and bronchi, called croup, that can result in a cough. Infection with bacteria usually affects the trachea only and can cause narrowing or even obstruction. As a major part of the respiratory tract, the trachea, when obstructed, prevents air from entering the lungs; thus, a tracheostomy may be required. Additionally, during surgery, if mechanical ventilation is required during anaesthesia, a tube is inserted into the trachea: this is called tracheal intubation.

Dexamethasone is a fluorinated glucocorticoid medication used to treat rheumatic problems, a number of skin diseases, severe allergies, asthma, chronic obstructive pulmonary disease (COPD), croup, brain swelling, eye pain following eye surgery, superior vena cava syndrome (a complication of some forms of cancer), and along with antibiotics in tuberculosis. In adrenocortical insufficiency, it may be used in combination with a mineralocorticoid medication such as fludrocortisone. In preterm labor, it may be used to improve outcomes in the baby. It may be given by mouth, as an injection into a muscle, as an injection into a vein, as a topical cream or ointment for the skin or as a topical ophthalmic solution to the eye. The effects of dexamethasone are frequently seen within a day and last for about three days.

The long-term use of dexamethasone may result in thrush, bone loss, cataracts, easy bruising, or muscle weakness. It is in pregnancy category C in the United States, meaning that it should only be used when the benefits are predicted to be greater than the risks. In Australia, the oral use is category A, meaning it has been frequently used in pregnancy and not been found to cause problems to the baby. It should not be taken when breastfeeding. Dexamethasone has anti-inflammatory and immunosuppressant effects.