Mononucleosis: Causes, Symptoms, Diagnosis, and Treatment

Mononucleosis, commonly referred to as “mono”, is a viral infection most often caused by the Epstein-Barr virus (EBV), a member of the herpes virus family. Mono is sometimes known as the "kissing disease" because the virus is spread primarily through saliva, making close contact like kissing or sharing drinks a common means of transmission. Although anyone can contract mono, it is most frequently diagnosed in teenagers and young adults, particularly those between the ages of 15 and 25.

Causes of Mononucleosis

The Epstein-Barr virus (EBV) is the primary cause of mononucleosis, though other viruses, such as cytomegalovirus (CMV), can sometimes lead to similar symptoms. EBV spreads through direct contact with saliva, but it can also be passed through blood or semen during sexual contact, organ transplants, or blood transfusions.

Once a person is infected with EBV, the virus remains dormant in the body for life. While it typically doesn’t cause recurrent illness, it can occasionally reactivate without causing symptoms. Most people are exposed to EBV in childhood, but children often experience mild or no symptoms when infected, while adolescents and adults are more likely to develop noticeable symptoms of mono.

Symptoms of Mononucleosis

Mono is known for causing fatigue and weakness, and its symptoms can last for weeks or even months. After exposure to the virus, symptoms usually appear after an incubation period of about 4 to 6 weeks. The severity of symptoms can vary, but the most common include:

1. Severe Fatigue: Fatigue is one of the hallmark symptoms of mono and can persist long after the initial illness subsides.

2. Fever: A persistent fever is common, typically in the range of 100–102°F (37.8–38.9°C).

3. Sore Throat: The throat can become extremely painful, and it’s often accompanied by swollen tonsils that may be covered in white patches.

4. Swollen Lymph Nodes: Lymph nodes in the neck and under the arms may become enlarged and tender.

5. Swollen Spleen: The spleen, which filters blood, can swell during a mono infection, causing abdominal discomfort or pain. In severe cases, a swollen spleen can rupture, which is a medical emergency.

6. Headache and Body Aches: Many individuals experience headaches, muscle aches, and general malaise.

7. Rash: Some individuals may develop a rash, particularly if they are treated with certain antibiotics, such as ampicillin or amoxicillin, for a mistaken diagnosis of a bacterial infection.

8. Liver Inflammation: Hepatitis, or inflammation of the liver, can develop, leading to jaundice (yellowing of the skin and eyes) in some cases.

Diagnosis of Mononucleosis

Diagnosing mono usually involves a combination of reviewing the patient’s symptoms, conducting a physical examination, and performing laboratory tests. The most commonly used diagnostic methods include:

1. Physical Exam: The doctor will check for swollen lymph nodes, an enlarged spleen, and an inflamed throat.

2. Blood Tests: A complete blood count (CBC) can detect an elevated number of white blood cells, which often occurs during mono. Additionally, specific tests, such as the monospot test or tests for EBV antibodies, can confirm the presence of the Epstein-Barr virus.

3. Liver Function Tests: In cases where liver inflammation is suspected, liver enzyme levels may be measured to assess liver function.

Treatment of Mononucleosis

There is no specific antiviral treatment for mono, and because it is a viral infection, antibiotics are not effective. Instead, treatment focuses on relieving symptoms and ensuring proper recovery. Key components of treatment include:

1. Rest: Rest is crucial, especially during the acute phase of the illness when fatigue is most severe.

2. Hydration: Drinking plenty of fluids helps prevent dehydration, especially if fever is present.

3. Pain Relievers: Over-the-counter medications like acetaminophen or ibuprofen can help reduce fever, sore throat, and body aches. Aspirin should be avoided in children due to the risk of Reye’s syndrome, a rare but serious condition.

4. Avoiding Strenuous Activity: Since mono can cause an enlarged spleen, patients should avoid strenuous activities and contact sports until fully recovered, as there is a risk of splenic rupture.

5. Throat Soothers: Gargling with salt water or using throat lozenges may help soothe a sore throat.

Complications of Mononucleosis

Most cases of mono resolve without complications, but in some instances, more serious issues can arise:

1. Splenic Rupture: This is a rare but serious complication of mono that can occur if the spleen becomes too enlarged. It requires immediate medical attention and may need surgery.

2. Liver Inflammation: Mild liver inflammation is common with mono, but in rare cases, it can lead to jaundice or hepatitis.

3. Anemia or Low Blood Counts: Mono can occasionally cause a decrease in the number of red blood cells, white blood cells, or platelets, leading to anemia or an increased risk of infections and bleeding.

4. Neurological Issues: In very rare cases, mono can lead to complications like Guillain-Barré syndrome, meningitis, or encephalitis.

Prevention of Mononucleosis

Since mono is spread through saliva, avoiding close contact with infected individuals can reduce the risk of transmission. Key preventive measures include:

1. Avoiding Kissing or Sharing Drinks: Avoid sharing food, drinks, utensils, or personal items with someone who has mono.

2. Practicing Good Hygiene: Frequent handwashing and disinfecting commonly touched surfaces can help reduce the spread of the virus.

3. Avoiding Close Contact with Infected Individuals: If someone has mono, they should avoid close physical contact with others until they recover.

Mononucleosis is a common viral infection, especially in adolescents and young adults, that primarily affects the lymph nodes, throat, and spleen. While the symptoms can be prolonged and severe, most people recover fully with supportive care. Preventive measures, such as avoiding the sharing of saliva, can help reduce the risk of infection. Though mono can have complications, they are relatively rare, and the majority of individuals recover without long-term issues.