When does the spleen typically peak in size during infectious mononucleosis?

In infectious mononucleosis, the spleen often undergoes significant changes due to the underlying viral infection, typically caused by the Epstein-Barr virus. The spleen serves as an important organ in the immune response, and its enlargement is a common finding in this condition, known as splenomegaly.

The peak in size of the spleen typically occurs around 12 days after the onset of symptoms. This timing correlates with the progression of the immune response and the body’s reaction to the virus. During the early stages of the infection, lymphocyte proliferation and the accumulation of immune cells in the spleen contribute to its enlargement, which becomes most pronounced approximately 12 days into the illness.

Monitoring spleen size during infectious mononucleosis is critical due to the risk of splenic rupture during physical activities, particularly in the weeks following the onset of symptoms, when the spleen is at its largest and most vulnerable. Understanding the timeline of splenomegaly, including its peak size, is essential for providing appropriate management and guidance to patients recovering from infectious mononucleosis.