Synonyms: Mono, Kissing Disease, Glandular Fever, Pfeiffer’s disease, Filatov’s disease.
Causative Organism: Epstein–Barr virus (EBV) -90%, Human Cytomegalovirus (CMV)
Infectious mononucleosis is recognized as a clinical syndrome consisting of fever, pharyngitis, and adenopathy.
EBV is transmitted through intimate contact with body secretions, especially saliva.
The first site of infection is pharyngeal epithelial cells followed by B-Lymphocytes.Circulating B cells spread the infection throughout the entire reticular endothelial system (RES), ie, liver, spleen, and peripheral lymph nodes. The host immune response involves cytotoxic T cells against infected B lymphocytes, resulting in enlarged, atypical lymphocytes (Downey cells).Lymphocytosis observed in the RES is caused by a proliferation of EBV-infected B lymphocytes. Pharyngitis observed in EBV infectious mononucleosis is caused by the proliferation of EBV-infected B lymphocytes in the lymphatic tissue of the oropharynx.
The most commonly used diagnostic criterion is the presence of 50% lymphocytes with at least 10% atypical lymphocytes (large, irregular nuclei), while the person also has a fever, pharyngitis, and swollen lymph nodes. Only half of the patients presenting with the symptoms held by mononucleosis and a positive heterophile antibody test (the monospot test) meet the entire set of criteria.
Most cases of EBV infectious mononucleosis are subclinical, and the only manifestation of EBV infection is a positive serological test. Mortality and morbidity rates due to uncomplicated primary EBV infectious mononucleosis are low.
Splenic rupture may be the initial presentation of EBV mononucleosis and such cases have high mortality. Hepatic necrosis caused by extensive EBV proliferation in the RES of the liver is the usual cause of death in affected males. EBV is the main cause of malignant B-cell lymphomas in patients receiving organ transplants.
Patients with EBV infection who present clinically with infectious mononucleosis invariably experience accompanying fatigue. Fatigue may resolve gradually in 3 months in most of the cases.
Infectious mononucleosis is generally self-limiting, so only symptomatic or supportive treatments are used.
CNS Complications: meningitis, encephalitis, hemiplegia, Guillain–Barré syndrome, and transverse myelitis.
Haematological: Anaemia and thrombocytopenia.
Jaundice and rarely hepatitis
Upper airway obstruction from enlarged tonsils
Cancers of lymphatic tissue