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Mononucleosis

Definition

Mononucleosis, or mono, is a viral infection that causes fever, sore throat, and swollen lymph glands, most often in the neck.

Alternative Names

Mono; Kissing disease; Glandular fever

Causes

Mono is often spread by saliva and close contact. It is known as "the kissing disease." Mono occurs most often in people ages 15 to 17, but the infection may develop at any age.

Mono is usually linked to the Epstein-Barr virus (EBV). Rarely, it is caused by other viruses, such as cytomegalovirus (CMV).

Symptoms

Mono may begin slowly with fatigue, a general ill feeling, headache, and sore throat. The sore throat slowly gets worse. Your tonsils become swollen and develop a whitish-yellow covering. Often, the lymph nodes in the neck are swollen and painful.

A pink, measles-like rash can occur, and is more likely if you take the medicine ampicillin or amoxicillin for a throat infection. (Antibiotics should NOT be given without a test that shows you have a strep infection.)

Common symptoms of mono include:

Less common symptoms:

Exams and Tests

Your health care provider will examine you. The exam may find:

  • Swollen lymph nodes in the front and back of your neck
  • Swollen tonsils with a whitish-yellow covering
  • Swollen liver or spleen
  • Skin rash

Blood tests will be done, including:

  • White blood cell (WBC) count - will be higher than normal
  • Monospot test - will be positive for infectious mononucleosis
  • Antibody titer - tells the difference between a current and past infection
Treatment

The goal of treatment is to relieve symptoms. Steroid medicine (prednisone) may be given if symptoms are severe.

Antiviral drugs, such as acyclovir, have little or no benefit.

To relieve typical symptoms:

  • Drink plenty of fluids.
  • Gargle with warm salt water to ease a sore throat.
  • Get plenty of rest.
  • Take acetaminophen or ibuprofen for pain and fever.

You should also avoid contact sports if your spleen is swollen (to prevent it from rupturing).

Outlook (Prognosis)

The fever usually drops in 10 days, and swollen lymph glands and spleen heal in 4 weeks. Tiredness usually goes away within a few weeks, but it may linger for 2 to 3 months.

Possible Complications

Complications of mononucleosis may include:

  • Anemia, which occurs when red blood cells in the blood are destroyed earlier than normal
  • Hepatitis with jaundice (more common in patients older than 35)
  • Swollen or inflamed testicles
  • Nervous system problems (rare), such as Guillain-Barré syndrome, meningitis, seizures, damage to the nerve that controls movement of the muscles in the face (Bell's palsy), and uncoordinated movements (ataxia)
  • Spleen rupture (rare; avoid pressure on the spleen)
  • Skin rash (uncommon)

Death is possible in people who have a weakened immune system.

When to Contact a Medical Professional

The early symptoms of mono feel very much like any other illness caused by a virus. You do not need to contact a health care provider unless your symptoms last longer than 10 days or you develop:

  • Abdominal pain
  • Breathing difficulty
  • Persistent high fevers (more than 101.5°F)
  • Severe headache
  • Severe sore throat or swollen tonsils
  • Weakness in your arms or legs
  • Yellow color in your eyes or skin

Call 911 or go to an emergency room if you develop:

  • Sharp, sudden, severe abdominal pain
  • Stiff neck or severe weakness
  • Trouble swallowing or breathing
Prevention

People with mono may be contagious while they have symptoms and for up to a few months afterwards. How long someone with the disease is contagious varies. The virus can live for several hours outside the body. Avoid kissing or sharing utensils if you or someone close to you has mono.

References

Frye R, Bailey J, Blevins AE. Clinical inquiries. Which treatments provide the most relief for pharyngitis pain? J Fam Pract. 2011;60:293-294.

Jenson HB. Epstein-Barr virus. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 246.

Schooley RT. Epstein-Barr virus infection. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 385.

Weber R. Pharyngitis. In: Bope ET, Kellerman RD, eds. Conn's Current Therapy 2012. 1st ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 1.

Mononucleosis, photomicrograph of cells
This so-called "Downy cell" is typical of lymphocytes infected by EBV (Epstein Barr Virus) or CMV (Cytomegalovirus) in infectious mononucleosis. Downy cells may be classified as types I, II, or III. This is a type II Downy cell.
Mononucleosis, photomicrograph of cells
This is a lymphocyte that has been infected by the Epstein-Barr Virus (EBV) or Cytomegalovirus (CMV) in infectious mononucleosis and is referred to as a "Downy cell". Downy cells may be classified as types I, II, or III; this is a type I Downy cell.
Infectious mononucleosis #3
Infectious mononucleosis is caused by the Epstein-Barr virus. It is a viral infection causing high temperature, sore throat, and swollen lymph glands. Infectious mononucleosis can be contagious if the infected person comes in close or intimate contact with another person through saliva or sexual contact.
Acrodermatitis
Acrodermatitis enteropathica is a skin condition peculiar to children that may be accompanied by mild symptoms of fever and malaise. It may also be associated with hepatitis B infection or other viral infections. The lesions appear as small coppery-red, flat-topped firm papules that appear in crops and sometime in long linear strings, often symmetric.
Splenomegaly
Splenomegaly is an enlargement of the spleen.
Infectious mononucleosis
Swollen lymph nodes, sore throat, fatigue and headache are some of the symptoms of mononucleosis, which is caused by the Epstein-Barr virus. It is generally self-limiting and most patients can recover in 4 to 6 weeks without medications.
Mononucleosis, photomicrograph of cell
This picture shows large, atypical lymphocytes (white blood cells). These cells are seen in viral infections, most commonly caused by the Epstein-Barr virus (infectious mononucleosis), cytomegalovirus diseases, and occasionally infectious hepatitis. This is an example of a type I Downy cell.
Gianotti-Crosti syndrome on the leg
Gianotti-Crosti disease is also called acrodermatitis of childhood. These red, elevated lesions do not contain pus and can occur on the limbs, buttocks, face, and neck.
Mononucleosis - view of the throat
Infectious mononucleosis causes a sore throat, enlarged lymph nodes, and fatigue. The throat may appear red and the tonsils covered with a whitish material. Mononucleosis and severe streptococcal tonsillitis appear quite similar. Unless there are other findings to suggest mononucleosis, a throat culture and blood studies may be necessary to make an accurate diagnosis.
Mononucleosis - mouth
Infectious mononucleosis is caused by the Epstein-Barr virus. In teenagers and young adults, there is frequently a sore throat and red tonsils with whitish spots (exudate), as seen in this picture. Enlarged lymph nodes and fatigue are also common.
Antibodies
Antigens are large molecules (usually proteins) on the surface of cells, viruses, fungi, bacteria, and some non-living substances such as toxins, chemicals, drugs, and foreign particles. The immune system recognizes antigens and produces antibodies that destroy substances containing antigens.

Review Date: 5/12/2014
Reviewed By: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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