In pathology, a cardinal sign or cardinal symptom is the primary or major clinical sign symptom

Symptom

A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...

 by which a diagnosis is made.

Often, there is a cluster of signs or symptoms that, taken together, are pathognomonic

Pathognomonic

Pathognomonic is a term, often used in medicine, that means characteristic for a particular disease. A pathognomonic sign is a particular sign whose presence means that a particular disease is present beyond any doubt...

 for a specific disease or syndrome

Syndrome

In medicine and psychology, a syndrome is the association of several clinically recognizable features, signs , symptoms , phenomena or characteristics that often occur together, so that the presence of one or more features alerts the physician to the possible presence of the others...

.

Examples

Inflammation

Inflammation

Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

 is characterized by five cardinal signs:

• rubor (redness
  Flushing (physiology)
  For a person to flush is to become markedly red in the face and often other areas of the skin, from various physiological conditions. Flushing is generally distinguished, despite a close physiological relation between them, from blushing, which is milder, generally restricted to the face, cheeks or...
  
  ),
• calor (increased heat),
• tumor (swelling
  Swelling (medical)
  In medical parlance, swelling is the transient enlargement or protuberance in the body and may include tumors. According to cause, it may be congenital, traumatic, inflammatory, neoplastic or miscellaneous....
  
  ),
• dolor (pain
  Pain
  Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
  
  ), and
• functio laesa (loss of function).

In acute exacerbations of chronic bronchitis

Acute exacerbations of chronic bronchitis

Acute exacerbations of chronic bronchitis are episodes of difficulty in breathing in a person with chronic bronchitis.In concomitant presence of emphysema, the underlying condition can be classified as chronic obstructive pulmonary disease , and the exacerbations termed "acute exacerbation of...

, diagnosis is normally based on the three cardinal signs of:

• Increased shortness of breath
• Increased sputum volume
• Purulent sputum