7 September 2020 Author : Luis Duarte Costa Infectious mononucleosis is caused by the Epstein-Barr virus, or human herpesvirus 4, which can also cause other diseases. This virus is not very contagious, but it has a wide distribution. Man seems to be its main reservoir, since it does not exist in the environment. In developing countries and in situations of close contact and poor hygiene conditions, antibodies against the virus in the population is high due to the frequency of exposure. This is particularly common in children, due to the characteristics of their habits and playing. In these regions, infection is rare in adults due to exposure at young ages. How mononucleosis is transmitted In infectious mononucleosis, transmission of the Epstein-Barr virus is done by oral contact with saliva from infected people, most often from asymptomatic carriers. Kissing and sharing objects contaminated with saliva , such as glasses or cutlery, are the most likely ways to contract the infection. After contagion, if the disease develops symptoms, the incubation period until they occur is 4 to 8 weeks. The virus is eliminated in the saliva for an average of 6 months after the onset of the disease. There are asymptomatic carriers who eliminate the virus in saliva intermittently throughout their lives. In addition to saliva, infected people may also have the virus present in sperm and vaginal secretions, but it is unclear whether there is contagion through sexual intercourse. Symptoms and diagnosis Infectious mononucleosis may not have any symptoms. This is common in children, who only have symptoms in 10% of cases, but it is also common in other age groups. The disease with symptoms is more common in adolescents and young adults , between 15 and 24 years old. Usually It is not serious, but it can imply prolonged periods of absence from classes or work. When the disease has symptoms , these are mainly: Fever; Pain and inflammation of the throat; Increased palpable lymph nodes in the neck (lymphadenopathy); Muscle pain (myalgia); Tiredness; Increased spleen volume (splenomegaly). For the doctor to diagnose the disease contribute: Physical examination; The patient symptoms and remaining history; Diagnostic tests, for example blood tests to assess the number and type of lymphocytes (a type of white blood cell), determine antibodies, search for the virus, eliminate other possible causes for symptoms. The diagnosis of infectious mononucleosis is often delayed in relation to the onset of the disease because the most common symptoms are not specific. They are common to other more frequent diseases and, therefore, delay the search for medical care. Excessive and unexplained tiredness is sometimes the main reason for seeking medical care and suspecting the disease. When complaints are just fever and sore throat, infectious mononucleosis can be mistaken for bacterial tonsillitis. However, the antibiotics that are used to treat bacterial tonsillitis have no effect on infectious mononucleosis, which is caused by a virus. The use of penicillin derived antibiotics in this disease can even give rise to the appearance of red spots on the body (erythema), a reaction to which there is no clear explanation, but which is not an allergy. In most cases, a single medical appointment is not enough to diagnose infectious mononucleosis or to eliminate this possibility. For example, when someone makes an appointment, whether scheduled or in an emergency department, with complaints suggestive of mononucleosis, it is usual for additional appointments to be indicated to finish the differential diagnosis and follow up on the disease. Maintaining follow-up until complete recovery is very important . Treatment and return to classes or professional activity There is no specific treatment against the mononucleosis virus. Therefore, the treatment of mononucleosis aims to combat symptoms (symptomatic treatment), especially fever and pain. The essential for recovery is to rest at home , eat a balanced diet and maintain good hydration. The rest period is variable, from 1 or 2 weeks to 1 month or more. The goal is to recover enough to return to classes or professional activity. When there is an increase in the volume of the spleen , which occurs in about 50% of cases, it is advisable not to practice physical activity , especially contact sports, or to make efforts, until this organ returns to normal. The intention is to avoid any trauma to the spleen that can cause it to rupture, as this problem is serious and requires immediate medical care. In patients with splenomegaly, it is prudent that once recovered the return to physical activity should be done gradually. Most people who develop infectious mononucleosis or kissing disease with symptoms recover completely and are immune to the disease . References: Manual MSD – Professional version and consumer version UpToDate Meet the internal medicine team from Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
