Asymptomatic

Pulmonary contusion due to trauma is an example of a condition that can be asymptomatic with half of people showing no signs at the initial presentation. The CT scan shows a pulmonary contusion (red arrow) accompanied by a rib fracture (purple arrow).

In medicine, any disease is classified asymptomatic if a patient tests as carrier for a disease or infection but experiences no symptoms. Whenever a medical condition fails to show noticeable symptoms after a diagnosis it might be considered asymptomatic.

Infections of this kind are usually called subclinical infections. Diseases such as mental illnesses or psychosomatic conditions are considered subclinical if they present some individual symptoms but not all those normally required for a clinical diagnosis. The term clinically silent is also found. Producing only a few, mild symptoms, disease is paucisymptomatic. Symptoms appearing later, after an asymptomatic incubation period, mean a pre-symptomatic period has existed.

Importance

Knowing that a condition is asymptomatic is important because:

• It may develop symptoms later and only then require treatment.
• It may resolve itself or become benign.
• It may be contagious, and the contribution of asymptomatic and pre-symptomatic infections to the transmission level of a disease helps set the required control measures to keep it from spreading.^[1]
• It is not required that a person undergo treatment. It does not cause later medical problems such as high blood pressure and hyperlipidaemia.^[2]
• Be alert to possible problems: asymptomatic hypothyroidism makes a person vulnerable to Wernicke–Korsakoff syndrome or beri-beri following intravenous glucose.^[3]
• For some conditions, treatment during the asymptomatic phase is vital. If one waits until symptoms develop, it is too late for survival or to prevent damage.

Examples

An example of an asymptomatic disease is cytomegalovirus (CMV) which is a member of the herpes virus family. "It is estimated that 1% of all newborns are infected with CMV, but the majority of infections are asymptomatic." (Knox, 1983; Kumar et al. 1984)^[4] In some diseases, the proportion of asymptomatic cases can be important. For example, in multiple sclerosis it is estimated that around 25% of the cases are asymptomatic, with these cases detected postmortem or just by coincidence (as incidental findings) while treating other diseases.^[5]

List

These are conditions for which there is a sufficient number of documented individuals that are asymptomatic that it is clinically noted. For a complete list of asymptomatic infections see subclinical infection.

Millions of women reported lack of symptoms during pregnancy until the point of childbirth or the beginning of labor; they didn't know they were pregnant. This phenomenon is known as cryptic pregnancies. ^[6]

See also

• Symptomatic
• Subclinical infection

References