Infectious Mononucleosis (cont.)

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How is mono diagnosed?

The diagnosis of mono is suspected by the doctor based on the above symptoms and signs. Mono is confirmed by blood tests that may also include tests to exclude other possible causes of the symptoms, such as tests to rule out strep throat. Early in the course of the mono, blood tests may show an increase in one type of white blood cell (lymphocyte). Some of these increased lymphocytes have an unusual or "atypical" appearance when viewed under a microscope, which suggests mono.

More specific blood tests, such as the monospot and heterophile antibody tests, can confirm the diagnosis of mono. These tests rely on the body's immune system to make measurable antibodies against the EBV. Unfortunately, the antibodies may not become detectable until the second or third weeks of the illness. A blood chemistry test may reveal inflammation and abnormalities in liver function. Diagnostic tests performed in the laboratory may be of value to rule out other causes of sore throat and fever, including cytomegalovirus infection, strep throat, and less common conditions such as acute HIV infection or toxoplasmosis.

What is the usual course and treatment of mono?

In most cases of mono, no specific treatment is necessary. The illness is usually self-limited and passes much the way other common viral illnesses resolve. Treatment is directed toward the relief of symptoms. Available antiviral drugs have no significant effect on the overall outcome of mono and may actually prolong the course of the illness. Occasionally, strep throat occurs in conjunction with mono and is best treated with penicillin or erythromycin (E-Mycin, Eryc, Ery-Tab, PCE, Pediazole, Ilosone). Ampicillin (Omnipen, Polycillin, Principen) and amoxicillin (Amoxil, DisperMox, Trimox) should be avoided if there is a possibility of mono since up to 90% of patients with mono develop a rash when taking these medications. If this happens, the individuals may then be inappropriately thought to have an allergy to penicillin.

For the most part, supportive or comfort measures are all that is necessary. Acetaminophen (Tylenol) can be given for fever and any headache or body aches. A sufficient amount of sleep and rest is important. The throat soreness is worst during the first five to seven days of illness and then subsides over the next seven to 10 days. The swollen, tender lymph nodes generally subside by the third week.

A feeling of fatigue or tiredness may persist for months following the acute phase of the illness. It is recommended that patients with mono avoid participation in any contact sports for three to four weeks after the onset of symptoms to prevent trauma to the enlarged spleen. The enlarged spleen is susceptible to rupture, which can be life threatening. Cortisone medication is occasionally given for the treatment of severely swollen tonsils or throat tissues which threaten to obstruct breathing.

Patients can continue to have virus particles present in their saliva for as long as 18 months after the initial infection. When symptoms persist for more than six months, the condition is frequently called "chronic" EBV infection. However, laboratory tests generally cannot confirm continued active EBV infection in people with "chronic" EBV infection.

Medically Reviewed by a Doctor on 9/25/2013

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Infectious Mononucleosis (Mono) - Symptoms Question: For infectious mononucleosis (mono), what were the symptoms and signs you experienced?
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Infectious Mononucleosis (Mono) - Causes Question: Most cases of mononucleosis occur in the 15-24 age group. How did you or your child "catch" mono?
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