Complications are unexpected events which occur during the process of diagnosis, management, or treatment of disease. As a general rule, complications are not viewed favorably, as they can make treatment much more difficult or threaten the patient's life, depending on the nature of the complications. Complications can take a wide array of forms, sometimes making them difficult to spot until they have already progressed considerably. In patients at risk of complications, careful monitoring is often used to detect signs at the early stages.
A classic example of a complication is a surgical complication, a situation in which a surgery does not go as expected. For example, a patient might be undergoing surgery and experience an erratic pulse in response to the anesthetics being used, creating a complication which could become dangerous. Surgical complications also arise when a surgeon discovers that a situation is more challenging than it looked from the outside, as commonly happens in emergency surgery, when patients may have catastrophic injuries which only become apparent upon inspection.
Medical complications can also arise in the course of treatment for a disease. For instance, a patient might react badly to the administration or a drug, or a patient might develop a secondary infection as a result of a weakened immune system. Some treatments are so intense that complications are expected, as in the case of things like chemotherapy and radiation. In these cases, the complication could be considered “iatrogenic,” meaning that it was created by the doctor's attempts at treatment, but complications can also arise spontaneously.
Some diseases are associated with a risk of complications. People with clotting disorders, for example, may be at risk of stroke, endocarditis, or heart attacks, while people with severe head injuries are at risk of permanent brain damage. Abscessed and infected wounds can lead to septicemia, or spread infection throughout the body. Diabetes, a chronic condition, is associated with a range of complications, some of which can be deadly.
Because every body is different, complications happen, often without any warning. Doctors try to reduce the risk of complications by gathering a complete medical history on their patients, and by keeping up on research in the field which can reveal new information about potential sources of complications. Surgical procedures, drugs, and other forms of treatment are also put through rigorous testing before being used on the general public, to assess the potential risk of complications and side effects.
Because some very strange interactions can cause complications, patients should always be honest with their doctors to ensure that they get the best treatment possible. A behavior, nutritional supplement, or symptom which may seem innocuous could lead to catastrophic complications if a doctor wasn't aware of it.