Download Infectious mononucleosis (IM) and Epstein

Infectious mononucleosis (IM)
and Epstein-Barr virus (EBV)
For Third- Year Medical Students
Dr: Hussein Mohammed Jumaah
CABM
Mosul Medical College
31/3/2014
Infectious mononucleosis (IM) and
Epstein-Barr virus (EBV)
EBV is a gamma herpes virus.
In developing countries, subclinical infection in
childhood is virtually universal.
In developed countries, primary infection may be
delayed until early adult life.
The virus is acquired from asymptomatic excreters
via saliva, by droplet infection, or by kissing.
EBV is not highly contagious ,isolation is unnecessary.
Infectious mononucleosis (IM) and
Epstein-Barr virus (EBV)
IM is an acute viral illness characterised by fever ,
pharyngitis, cervical lymphadenopathy, and
lymphocytosis.
Whereas ~90% of cases of IM are due to EBV,
5–10% of cases are due to Cytomegalovirus (CMV).
CMV is the most common cause of heterophilenegative mononucleosis.
Less common causes rubella ,Toxoplasma, HIV,
herpesvirus 6, hepatitis viruses and drug reactions.
Clinical features
IM has a prolonged and undetermined incubation
period, followed by a prodrome of fever,
headache and malaise, succeeded by IM
with severe pharyngitis, which may include tonsillar
exudates, and non-tender cervical
lymphadenopathy.
Palatal petechiae, periorbital oedema,
splenomegaly, macular, petechial or erythema
multiforme rashes may occur.
Clinical features
In most cases fever resolves over 2 weeks, and
other abnormalities settle over a further few weeks.
EBV may present with jaundice, PUO* or with a
complication.
Death is rare but can occur due to
1. Respiratory obstruction.
2. Haemorrhage (splenic rupture or
thrombocytopenia).
3. Encephalitis .
*pyrexia of unknown origin
Complications of Epstein–Barr virusn infection
Diagnosis
In children under 10 years the illness is
mild and short-lived, but in adults over
30 years of age it can be severe and
prolonged.
Investigations
Atypical lymphocytes are common in
EBVinfection but also occur in other
causes of IM, HIV infection, viral
hepatitis, mumps and rubella. The most
commonly used diagnostic criteria is
the presence of 50% lymphocytes.
(at least 10% atypical) .
Atypical lymphocytes.
enlarged lymphocytes that
have abundant cytoplasm,
vacuoles, and indentations
of the cell membrane .
Investigations
A 'heterophile' antibody is present during the
acute illness and convalescence, agglutinates
erythrocytes of other species, e.g. sheep and
horse.
detected by the classical
Paul-Bunnell titration or
a more convenient slide test such as the
'Monospot'.
Investigations
Specific EBV serology (immunofluorescence) can be
used to confirm the diagnosis if necessary.
Acute infection is characterised by IgM antibodies
against the viral capsid, antibodies to EBV early
antigen and the initial absence of antibodies to
EBV nuclear antigen (anti-EBNA).
Seroconversion of anti-EBNA at approximately1
month after the initial illness may confirm the
diagnosis in retrospect.
CNS infections may be diagnosed by detection of
viral DNA in cerebrospinal fluid .
Management
largely symptomatic. If a throat culture yields
aβ-haemolytic streptococcus, a course of penicillin
should be prescribed. ampicillin or amoxicillin in
this condition commonly causes an itchy macular
rash, and should be avoided .
When pharyngeal oedema is severe, a short
course of corticosteroids, e.g. prednisolone 30 mg
daily for 5 days, may help.
Antivirals are not sufficiently active against EBV .
Return to work or school is governed by
the patient's physical fitness. contact sports
should be avoided until splenomegaly has
completely resolved because of the danger
of splenic rupture.
10% of patients with IM suffer a chronic
relapsing syndrome .
Shingles (herpes zoster)
Shingles (herpes zoster)
After initial infection ,Varicella zoster
virus ,(VZV) persists in latent form in
the dorsal root ganglion of sensory
nerves and can reactivate in later life
as a localised rash or with other clinical
manifestations.
Commonly seen in the elderly, shingles
may also present in younger patients
with immune deficiency.
Chickenpox may be contracted from
acase of shingles but not vice versa.
It is not clear why this happens.
Clinical features
Burning discomfort occurs in the affected
dermatome, where discrete vesicles appear
3-4 days later, associated with a brief viraemia
Clinical features
and can
produce distant satellite 'chickenpox'
lesions.
Severe disease, a prolonged duration of rash,
multiple dermatomal involvement or recurrence
suggests underlying immune deficiency.
Clinical features
Thoracic dermatomes are most
Commonly involved .
Ophthalmic division of the
trigeminal nerve is also frequently
affected;vesicles may appear on the
cornea and lead to ulceration,and
can lead to blindness.
Bowel and bladder dysfunction
occur with sacral nerve root
involvement.
The virus occasionally causes
myelitis or encephalitis.
Clinical features
Ramsay Hunt syndrome
Involvement of the Geniculate ganglion
causes facial palsy, ipsilateral loss of taste
and buccal ulceration, plus a rash in the
external auditory canal. This may be mistaken
for Bell's palsy.
Post-herpetic neuralgia
Postherpetic neuralgia arises in approximately
20% of patients .
Troublesome persistence of pain for 1-6
months or longer, following healing of the rash.
It is more common with advanced age.
Management and prevention
Aciclovir has been shown to reduce both
early- and late-onset pain. new drugs
valaciclovir and famciclovir .
demonstrate similar or superior efficacy
and good safety and tolerability.
Post-herpetic neuralgia requires
aggressive analgesia, along with agents
such as amitriptyline or gabapentin.
Capsaicin cream may be helpful.
Although controversial, corticosteroids
have not been demonstrated to reduce
post-herpetic neuralgia to date.
Acyclovir for chickenpox/shingles
Aciclovir shortens symptoms in chickenpox by an
average of 1 day. In shingles aciclovir reduces
pain by 10 days and the risk of post-herpetic
neuralgia by 8%. Aciclovir is therefore costeffective in shingles but not chickenpox.'
Human VZ immunoglobulin (VZIG) is used to
attenuate infection in people who have had
significant contact with VZV, are susceptible to
infection (i.e. have no history of chickenpox or shingles
and are negative for serum VZV IgG) and are at risk
of severe disease (e.g. immunocompromised, steroidtreated or pregnant).
Newborn whose mother develops chickenpox no more
than 5 days before delivery or 2 days after delivery.
Ideally, VZIG should be given within 7 days of
exposure, but it may attenuate disease even if given up
to 10 days afterwards.
Susceptible contacts who develop severe chickenpox
after receiving VZIG should be treated with aciclovir.
A zoster vaccine (Zostavax) ,VZV vaccine ,.
Is a live, attenuated . Is exceedingly safe ,On
March 24, 2011, the Food and Drug Administration
(FDA) approved its use for the prevention of shingles
in individuals 50 to 59 years of age, including
persons who have already had an episode of
shingles.
should not be given to individuals who have
a. A weakened immune system
b. Individuals with active, untreated tuberculosis.
c. Pregnant women should not receive this vaccine.
UK ,its use has been restricted to non-immune
healthcare workers and household contacts of
immunocompromised individuals.
Children receive one dose after 1 year of age and
a second dose at 4–6 years of age; seronegative
adults receive two doses at least 1 month apart.
The vaccine may also be used prior to planned
iatrogenic immunosuppression, e.g. before transplant.