biology of infectious disease
infections
Fever in Adults
Substances that cause fever are called pyrogens. Pyrogens can come from inside or outside the body. Microorganisms and the substances they produce (such as toxins) are examples of pyrogens formed outside the body. Pyrogens formed inside the body are usually produced by monocytes and macrophages (two types of white blood cells). Pyrogens from outside the body can cause fever by stimulating the body to release its own pyrogens or by directly affecting the Fever . Infection is not the only cause of fever. Fever may also result from inflammation, a reaction to a drug, an Overview of Allergic Reactions , Many disorders can cause fever. They are broadly categorized as Infectious (most common) Neoplastic (cancer) Inflammatory An infectious cause is highly likely in adults with a fever that lasts 4 days or less. A noninfectious cause is more likely to cause fever that lasts a long time or returns. Many cancers cause fever. Inflammatory disorders that cause fever include joint, connective tissue, and blood vessel disorders such as Rheumatoid Arthritis (RA) , Also, an isolated, short-lived (acute) fever in people with cancer or a known inflammatory disorder is most likely to have an infectious cause. In healthy people, an acute fever is unlikely to be the first sign of a chronic illness. Drugs sometimes cause fever. For example, beta-lactam antibiotics (such as Penicillins ) and sulfa drugs can trigger a fever. Drugs that can cause an extremely high temperature include certain illicit drugs (such as 