Another diagnostic test that indicates mononucleosis is the Paul-Bunnell heterophil agglutination test, which demonstrates the presence of certain antibodies capable of causing clumping of cells in a sample of sheep's blood. In about 8 to 10 per cent of all cases, the liver is involved and jaundice occurs, resulting in a condition that resembles infectious hepatitis. In rare cases, the heart, lungs, and central nervous system may also be affected. The lymph nodes and spleen may both remain enlarged for sometime after other symptoms have disappeared. Treatment is chiefly symptomatic.
Rest is especially important in the early stages of the disease, or later if the liver is involved.
There is as yet no specific treatment for mononucleosis, and no immunization is available. Headache and sore throat may be relieved by aspirin and gargles. Although the more obvious symptoms may disappear after a period of rest, sufficient rest and curtailed activities must be maintained in order to improve the patient's severely weakened condition and prevent recurrence. There is often mental as well as physical fatigue, especially among students, and in these cases some mental depression may accompany convalescence. Chronic, lingering infectious mononucleosis occurs in some patients.