Acute (medicine)In medicine, describing a disease as acute denotes that it is of recent onset; it occasionally denotes a short duration. The quantification of how much time constitutes "short" and "recent" varies by disease and by context, but the core denotation of "acute" is always qualitatively in contrast with "chronic", which denotes long-lasting disease (for example, in acute leukaemia and chronic leukaemia). In the context of the mass noun "acute disease", it refers to the acute phase (that is, a short course) of any disease entity.
Bacterial pneumoniaBacterial pneumonia is a type of pneumonia caused by bacterial infection. Streptococcus pneumoniae () is the most common bacterial cause of pneumonia in all age groups except newborn infants. Streptococcus pneumoniae is a Gram-positive bacterium that often lives in the throat of people who do not have pneumonia. Other important Gram-positive causes of pneumonia are Staphylococcus aureus () and Bacillus anthracis.
Atypical pneumoniaAtypical pneumonia, also known as walking pneumonia, is any type of pneumonia not caused by one of the pathogens most commonly associated with the disease. Its clinical presentation contrasts to that of "typical" pneumonia. A variety of microorganisms can cause it. When it develops independently from another disease, it is called primary atypical pneumonia (PAP). The term was introduced in the 1930s and was contrasted with the bacterial pneumonia caused by Streptococcus pneumoniae, at that time the best known and most commonly occurring form of pneumonia.
Acute exacerbation of chronic obstructive pulmonary diseaseAn acute exacerbation of chronic obstructive pulmonary disease, or acute exacerbations of chronic bronchitis (AECB), is a sudden worsening of chronic obstructive pulmonary disease (COPD) symptoms including shortness of breath, quantity and color of phlegm that typically lasts for several days. It may be triggered by an infection with bacteria or viruses or by environmental pollutants. Typically, infections cause 75% or more of the exacerbations; bacteria can roughly be found in 25% of cases, viruses in another 25%, and both viruses and bacteria in another 25%.
ParenchymaParenchyma (pəˈɹɛŋkᵻmə) is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms. The term parenchyma is Neo-Latin from the n word παρέγχυμα n parenchyma meaning 'visceral flesh', and from παρεγχεῖν parenkhein meaning 'to pour in' from παρα- para- 'beside' + ἐν en- 'in' + χεῖν khein 'to pour'. Originally, Erasistratus and other anatomists used it to refer to certain human tissues.
