Infectious mononucleosis 105807 225975836 2008-07-16T08:08:06Z Raguleader 218248 Removed vandalism --~~~~ {{Refimprove|date=May 2008}} {{Infobox_Disease |o Name = Infectious mononucleosis | Image = Atypical lcyte.jpg | Caption = Infectious mononucleosis smear showing reactive (atypical) lymphocytes (in blue) between normal red blood cells. | DiseasesDB = 4387 | ICD10 = {{ICD10|B|27||b|25}} | ICD9 = {{ICD9|075}} | ICDO = | OMIM = | MedlinePlus = 000591 | eMedicineSubj = emerg | eMedicineTopic = 319 | eMedicine_mult = {{eMedicine2|med|1499}} {{eMedicine2|ped|705}} | MeshID = D007244 }} '''''Infectious mononucleosis''''', also known as '''Pfeiffer's disease''', '''mono''' (in [[the United States of America]]) and more commonly known as '''glandular fever''' in other English-speaking countries. It occurs most commonly in [[adolescent]]s and young adults, where it is characterized by [[fever]], sore throat, muscle soreness, and fatigue. Infectious mononucleosis typically produces a mild illness in small children, and is often asymptomatic. Mononucleosis is predominantly caused by the [[Epstein-Barr virus]] (EBV), which infects [[B cell]]s (B-lymphocytes), producing a reactive [[lymphocytosis]] predominantly consisting of [[atypical lymphocyte]]s, a specific type of [[T-cell]] that gives the disease its name. The name "kissing disease" is often applied to '''mono''' in casual speech, as in developed countries it is most common at the same age when adolescents and young adults are initiating romantic behavior. This co-occurrence is not apparent in undeveloped countries, where poor sanitation and close living arrangements cause the causative virus to be spread at a much earlier age, when the disease is mild and seldom diagnosed. == Symptoms == * '''[[Fever]]'''&mdash;this varies from mild to severe, but is seen in nearly all cases. * '''Tender and enlarged/swollen [[lymph node]]s'''&mdash;particularly the posterior [[cervical lymph nodes]]. * '''[[Sore throat]]'''&mdash;White patches on the tonsils and back of the throat are often seen * '''[[Muscle weakness]]''' and '''[[Mental fatigue]]''' (sometimes extreme) Additional symptoms include: * ''Enlarged [[spleen]]'' ([[splenomegaly]], which may lead to rupture) and/or [[liver]] ([[hepatomegaly]]) * [[Petechial]] [[hemorrhage]] * '''[[Abdominal pain]]''' - a possible symptom of a potentially fatal rupture of the spleen.<ref>{{cite journal |author=Chapman AL, Watkin R, Ellis CJ |title=Abdominal pain in acute infectious mononucleosis |journal=BMJ |volume=324 |issue=7338 |pages=660–1 |year=2002 |pmid=11895827 |doi=10.1136/bmj.324.7338.660}}</ref> * [[Aching muscles]] * [[Headache]] * [[Loss of appetite]] * [[Depression (mood)|Depression]] * Diarrhea * Dizziness or disorientation * Uncontrolled shaking at times * Unable to swallow due to enlarged [[tonsils]] * Dry cough * Supra-orbital [[oedema]]&mdash;the eyes become puffy and swollen&mdash;may occur in the early stages of infection After an initial [[prodrome]] of 1-2 weeks, the fatigue of infectious mononucleosis often lasts from 1-2 months. The virus can remain dormant in the B cells indefinitely after symptoms have disappeared, and resurface at a later date. Many people exposed to the [[Epstein-Barr virus]] do not show symptoms of the disease, but carry the virus. This is especially true in children, in whom infection seldom causes more than a very mild cold which often goes undiagnosed. Children are typically just carriers of the disease. This feature, along with mono's long (4 to 6 week) [[incubation period]], makes [[epidemiology|epidemiological]] control of the disease impractical. About 6% of people who have had infectious mononucleosis will relapse.{{Fact|date=June 2008}} Mononucleosis can cause the spleen to swell. Rupture may occur without trauma,{{Fact|date=February 2008}} but impact to the spleen is also a factor. Other complications include [[hepatitis]] (inflammation of the liver) causing elevation of serum bilirubin (in approximately 40% of patients), jaundice (approximately 5% of cases), and [[anemia]] (a deficiency of red blood cells). In rare cases, death may result from severe hepatitis or splenic rupture. Although most cases of mononucleosis are caused by the E.B. virus, the condition is defined by the clinical presentation and laboratory findings. [[Cytomegalovirus]] can produce a similar illness, usually with less throat pain, and also generate [[atypical lymphocyte]] proliferation. In recent years, as precise virological and serological studies are more commonly done to identify the actual causative virus, some clinicians have taken to use "mononucleosis" to refer only to the E.B. virus cases. Symptoms similar to those of mononucleosis can also be caused by [[adenovirus]], acute HIV infection and the [[protozoa]]n ''[[Toxoplasma gondii]]''. ==Diagnosis== {{Expand-section|date=June 2008}} [[Image:Infectious Mononucleosis.jpg|right|thumb|Peripheral blood smear (low power) showing [[lymphocytosis]] from a 16-year-old male with [[pharyngitis]] and positive [[monospot test]].]] Laboratory findings usually include an elevated [[white blood cell]] count and abnormal [[liver function tests]]. The white cell count elevation is predominantly in the [[lymphocyte]] portion, and of those the majority is often of the [[atypical lymphocyte|atypical]] form characteristic of the disease. Specific tests for EBV include: * A [[monospot test]] (positive for infectious mononucleosis) * [[Epstein-Barr virus]] [[antigen]] by [[immunofluorescence]] (positive for EBV) * Epstein-Barr virus [[antibody titer]]s to help distinguish acute infection from past infection with EBV ==Transmission== {{disputed-section|date=May 2008}} Mononucleosis is typically transmitted from asymptomatic individuals through [[saliva]], earning it the name "the kissing disease", or by sharing a drink, or sharing eating utensils. It may also be transmitted through blood or the air. As with many viral infections, such as [[chicken pox]], antibodies are developed by individuals who become infected with the disease and recover. In most individuals, these [[antibody|antibodies]] remain in their system, creating lifelong immunity to further infections.<ref>{{cite web |title=Mononucleosis -- Causes |url=http://www.emedicinehealth.com/mononucleosis/page2_em.htm |date=12/7/2007 |publisher=eMedicineHealth |accessdate=2008-03-01}}</ref> == Atypical presentations of mononucleosis/EBV infection == In small children, the course of the disease is frequently asymptomatic. Some adult patients suffer fever, tiredness, lassitude (abnormal fatigue), depression, lethargy, and chronic lymph node swelling, for months or years. This variant of mononucleosis has been referred to as chronic EBV syndrome or [[chronic fatigue syndrome]] (CFS), although CFS is a distinct condition from IM. Still, current studies suggest there is an association between infectious mononucleosis and CFS.<ref name="Hickie">{{cite journal |author=Hickie I, Davenport T, Wakefield D, ''et al'' |title=Post-infective and chronic fatigue syndromes precipitated by viral and non-viral pathogens: prospective cohort study |journal=BMJ |volume=333 |issue=7568 |pages=575 |year=2006[: |pmid=16950834 |doi=10.1136/bmj.38933.585764.AE}}</ref> In case of a weakening of the immune system, a reactivation of the Epstein-Barr virus is possible; in CFS there is evidence of immune activation also. "Chronic fatigue states" as defined by the CDC criteria for CFS, appear to occur in 10% of those who contract mononucleosis.<ref name="Hickie"/> Chronic fatigue may then be a rather common side effect of infectious mononucleosis. On the other hand, studies conducted by the CDC{{Fact|date=February 2007}} and others{{Who|date=February 2007}} have discounted a link between EBV and CFS. Perhaps a majority of chronic post infectious "fatigue states" appear not to be caused by a chronic viral infection, but are triggered by the acute infection.{{Fact|date=December 2007}} Direct and indirect evidence of persistent viral infection has been found in CFS, for example in muscle and via detection of an unusually low molecular weight [[RNase L]] enzyme, although the commonality and significance of such findings is disputed. Hickie et al contend that mononucleosis appears to cause a hit and run ''injury'' to the brain in the early stages of the acute phase, thereby causing the chronic fatigue state. This would explain why in mononucleosis, fatigue very often lingers for months after the Epstein Barr virus has been controlled by the immune system. Just how infectious mononucleosis changes the brain and causes fatigue (or lack thereof) in certain individuals remains to be seen. Such a mechanism may include activation of microglia in the brain of some individuals during the acute infection. Microglia may remain activated or "damaged" for months following infection, thereby causing a slowly dissipating fatigue. Secondary infections can occur. Such infections include mild swelling of the cartilage between the sternum and ribs occurring approximately one month after initial diagnosis. == Treatment == Infectious mononucleosis is generally self-limiting and only symptomatic and/or supportive treatments are used.<ref name="Merck18">{{cite book |editors=Beers MH, Porter RS, Jones TV, Kaplan JL, Berkwits M, editors. |title=The Merck manual of diagnosis and therapy |edition=18th ed. |publisher=Merck Research Laboratories |location=Whitehouse Station (NJ) |year=2006 |isbn=0-911910-18-2}}</ref> Rest is recommended during the acute phase of the infection, but activity should be resumed once acute symptoms have resolved. Nevertheless heavy physical activity and contact sports should be avoided to abrogate the risk of splenic rupture, for at least one month following initial infection and until splenomegaly has resolved, as determined by [[Medical ultrasonography|ultrasound scan]].<ref name="Merck18"/> In terms of pharmacotherapies, [[paracetamol|acetaminophen/paracetamol]] or [[non-steroidal anti-inflammatory drug]]s (NSAIDs) may be used to reduce fever and pain. Intravenous [[corticosteroid]]s, usually [[hydrocortisone]] or [[dexamethasone]], are not recommended for routine use<ref>{{cite journal | author=Candy B, Hotopf M. | year=2006 | issue=4 | pages=CD004402 | journal=Cochrane Database Sys Rev | title=Steroids for symptom control in infectious mononucleosis | pmid=16856045 | doi=10.1002/14651858.CD004402.pub2 }}</ref> but may be useful if there is a risk of airway obstruction, severe [[thrombocytopenia]], or [[hemolytic anemia]].<ref name="TGAntibiotic13">Antibiotic Expert Group. Therapeutic guidelines: Antibiotic. 13th ed. North Melbourne: Therapeutic Guidelines; 2006.</ref><ref name="WebMD">{{cite web |title=Infectious Mononucleosis |url=http://www.webmd.com/hw/infection/hw168622.asp |date= January 24, 2006 |publisher=WebMD |accessdate=2006-07-10}}</ref> There is little evidence to support the use of [[aciclovir]], although it may reduce initial viral shedding.<ref name="Torre1999">{{cite journal |author=Torre D, Tambini R |title=Acyclovir for treatment of infectious mononucleosis: a meta-analysis |journal=Scand. J. Infect. Dis. |volume=31 |issue=6 |pages=543–7 |year=1999 |pmid=10680982 |doi=}}</ref> However, the antiviral drug [[valacyclovir]] has recently been shown to lower or eliminate the presence of the Epstein-Barr virus in subjects afflicted with acute mononucleosis, leading to a significant decrease in the severity of symptoms. <ref name="pmid17369082">{{cite journal |author=Balfour HH, Hokanson KM, Schacherer RM, ''et al'' |title=A virologic pilot study of valacyclovir in infectious mononucleosis |journal=J. Clin. Virol. |volume=39 |issue=1 |pages=16–21 |year=2007 |pmid=17369082 |doi=10.1016/j.jcv.2007.02.002}}</ref><ref>{{cite journal |author=Simon et al. |title=The Effect of Valacyclovir and Prednisolone in Reducing Symptoms of EBV Illness In Children: A Double-Blind, Placebo-Controlled Study. |journal=International Pediatrics |volume=18 |issue=3 |pages=164–169 |year=2003 |month=March}}</ref><ref>{{cite journal |author=Balfour HH, Hokanson KM, Schacherer RM, ''et al'' |title=A virologic pilot study of valacyclovir in infectious mononucleosis |journal=J. Clin. Virol. |volume=39 |issue=1 |pages=16–21 |year=2007 |pmid=17369082 |doi=10.1016/j.jcv.2007.02.002}}</ref> [[Antibiotic]]s are not used as they are ineffective against viral infections. The antibiotics [[amoxicillin]] and [[ampicillin]] are contraindicated in the case of any coinciding bacterial infections during mononucleosis because their use can frequently precipitate a non-allergic rash. In a small percentage of cases, mononucleosis infection is complicated by co-infection with [[streptococcus|streptococcal]] infection in the throat and tonsils (strep throat). [[Penicillin]] or other antibiotics (with the exception of the two mentioned above) should be administered to treat the strep throat. [[Opioid]] analgesics are also contraindicated due to risk of [[respiratory depression]].<ref name="TGAntibiotic13" /> ==Morbidity and mortality== Fatalities from mononucleosis are near impossible in developed nations. Uncommon, nonfatal complications exist, including various forms of CNS and hematological affection: * CNS: [[Meningitis]], [[encephalitis]], [[hemiplegia]] and transverse [[myelitis]]. EBV infection has also been proposed as a risk factor for the development of [[multiple sclerosis]] (MS)<ref>{{cite journal | author = Ascherio A, Munger KL | title = Environmental risk factors for multiple sclerosis. Part I: the role of infection | journal = Ann. Neurol. | volume = 61 | issue = 4 | pages = 288–99 | year = 2007 | pmid = 17444504 | doi = 10.1002/ana.21117}}</ref>, but this has not been affirmed. * Hematologic: EBV can cause [[autoimmune hemolytic anemia]] (direct [[Coombs test]] is positive) and various [[cytopenia]]s. ==References== {{reflist|2}} {{Viral diseases}} [[Category:Viral diseases]] [[ca:Mononucleosi infecciosa]] [[cs:Infekční mononukleóza]] [[da:Mononukleose]] [[de:Pfeiffer-Drüsenfieber]] [[el:Λοιμώδης μονοπυρήνωση]] [[es:Mononucleosis infecciosa]] [[fr:Mononucléose infectieuse]] [[hr:Mononukleoza]] [[id:Demam kelenjar]] [[it:Mononucleosi infettiva]] [[he:מונונוקלאוזיס זיהומי]] [[lt:Infekcinė mononukleozė]] [[hu:Mononucleosis]] [[nl:Klierkoorts]] [[ja:伝染性単核球症]] [[no:Mononukleose]] [[pl:Mononukleoza zakaźna]] [[pt:Mononucleose infecciosa]] [[ru:Инфекционный мононуклеоз]] [[fi:Mononukleoosi]] [[sv:Körtelfeber]] [[uk:Інфекційний мононуклеоз]]