Viral infection in a child (Mumps, Measles, Rubella, Erythema infectiosum, Parvovirus B19, Roseola infantum (HHV6), Chickenpox, Hand, foot and mouth disease) Flashcards
What are the types of human herpes viruses?
Which infections are associated with these fetal complications?
- limb defects
- cerebral palsy
- cataracts
- hydrops fetalis
- choroidoretinitis
- limb defects - acute varicella in pregnancy
- cerebral palsy - acute CMV
- cataracts - rubella
- hydrops fetalis - parvovirus
- choroidoretinitis - toxoplasmosis
Which two infections shed antigens into urine?
Legionella penumophila
Streptococcus pneumoniae
What is the incubation period of measles? How long does the rash last?
Incubation 10-14 days
5 days
How is measles spread? What type of pathogen causes measles?
RNA paramyxovirus
Droplet spread
Highly infectious during viral shedding which starts just before symptoms and continues until ~day 5 of symptoms (when fever is worst)
What are the presenting features of measles?
Prodrome: irritability, conhynctivitis, fever.
- Rash starts behind ears
- Cough
- Coryza
- Rash 5 days
- Fever
- Koplik spots
- Conjunctivitis
Which age groups have the most seveere disease with chickenpox, parvovirus b19 (HPV-B19) and measles?
Older children and adults
What is shown?
White spots on buccal mucosa, seen against a bright red background = Koplik spots
Pathognomonic of measles but difficult to see
Describe the appearance of this rash seen in measles.
- Spreads downwards from behind the ears
- Covers whole body
- Discrete maculopapular rash initially then becomes blotchy and confluent
- May desquamate in second week
What investigations are used to diagnose measles infection?
PCR
Serology - IgM antibodies can be detected within a few days of rash onset
What are the complications of measles?
NB: measles is a major cause of death in childhood in low-income countries
Respiratory:
- Otitis media
- Pneumonia
- Secondary bacterial infection
- Tracheitis
Neurological:
- EEG abnormalitiies and febrile seizures
- Encephalitis
- SSPE (subacute sclerosing panencephalitis - in adolescence after measles in childhood)
Other:
- Diarrhoea
- Hepatitis
- Appendicitis
- Corneal ulceration
- Myocarditis
What is the epidemiology of measles?
Incidence has declined dramatically since immunisation but a recent small increase has resulted from reduction in vaccine uptake (MMR)
MMR is the best at reducing morbidity and mortality from measles
What is the management of measles? What is the role of vitamins?
Supportive
Isolation
Inform public health - notifiable disease
Ribavarin if immunocompromised
Vitamin A may modulate the immune response and can be given in low-income countries - this is because vitamin A deficiency can lead to an impaired cell-mediated immune respoonse.
(Offer vaccine to any child who comes into contact with measles and is not immunised within 72 hours)
How can an impaired cellular response (e.g. in HIV) in measles lead to a difference in presentation?
Impaired cellular response may cause:
- Absence of rash
- Increased risk of dissemination e.g. giant-cell pneumonia or encephalitis
How common is encephalitis in measles? When does it occur? What are the symptoms and long-term complications?
1 in 5000 affected within a few days of illness
Symptoms of headache, lethargy, irritability and proceeding to seizures and ulimately coma.
Mortality is 15%
Morbidity - long-term seizures, deafness, hemiplegia, severe learning difficulties, affecting up to 40% of survivors.
What is the cause of SSPE in measles? When and how does it present? How common is it? How is it diagnosed?
Caused by a variant of the measles virus which persists in CNS
Presents ~7 years after measles illness with loss of neurological function which progresses to dementia and death over several years,
Affects 1 in 100,000 previously infected - most had measles at <2 years old. But rare overall since immunisation against measles.
Diagnosis is clinical supported by findings of high levels of measles antibody in blood and CSF and EEG abnormalities.
What kind of pathogen causes mumps? What time of year does it mostly occur?
RNA paramyxovirus
Tends to occur in winter and spring
How does mumps spread? What cells does it replicate in?
Spread by droplets
Replicates in epithelial cells
Repiratory tract epithelial cells -> parotid glands –> other tissues
What is the incubation period of mumps? When is a patient infectious during illness?
Infective 7 days before and 9 days after parotid swelling starts
Incubation period = 14-21 days
What are the clinical features of mumps?
- Fever - disappears within 3-4 days
- Malaise, muscular pain
- Parotitis (‘earache’, ‘pain on eating/drinking’): unilateral initially then becomes bilateral in 70%
BUT subclinical in 30% of cases
May have pancreatic involvement –> raised plasma amylase
Generally mild and self limiting
What is the efficacy of the MMR for mumps?
80%
What is the management of mumps?
- rest
- paracetamol for high fever/discomfort
- notifiable disease
What are the complications of mumps?
- Orchitis - uncommon in pre-pubertal males but occurs in around 25-35% of post-pubertal males. Usually unilateral and although reduction in sperm count may occur infertility is uncommon. Typically occurs four or five days after the start of parotitis
- Hearing loss - usually unilateral and transient
- Meningoencephalitis
- Pancreatitis –> raised amylase
- Viral meningitis and encephalitis - lymphocytes raised in CSF in 50% but meningeal signs only seen in 10% and encephalitis in 1 in 5000
Rarely oophritis, mastitis and arthritis may occur.
What is the most common illness associated with parvovirus B19 infection?
Erythema infectiosum aka Fifth disease aka ‘Slapped-cheek’ syndrome
What is shown?
Slapped cheek disease caused by parvovirus B19
Howevver, in adults and women it can look like a lace-like rash as shown below.
Which two patient groups are at risk of parvovirus B19 infection? Is it common in the elderly?
Haemoglobinopathies - parvovirus replicates in red blood cell precursors expressing the P antigen. Can lead to aplastic crises.
Immunosuppressed patients - e.g. HIV, bone marrow transplant recipients.
Uncommon in elderly because seropositivity increases with age.
What is erythema infectiosum also known as? What is the cause?
Fifth disease - because it was the 5th of a group of illnesses with similar rashes to be named.
Parvovirus B19 - a DNA virus
What are the clinical features of erythema infectiosum? Which part of the body is rarely affected?
Viraemic phase of
- mild fever - hardly noticeable
- malaise
- headache
- myalgia
Followed by
- characteritic rash on the face (‘slapped-cheek’) a week later - child starts to feel better when the rash appears
- ‘lace’-like rash on trunk and limbs
- arthralgia or arthritis are common in adults
Unlike other rashes it rarely affects the palms and soles.
What are the different types of disease/complications caused by parvovirus B19 infection?
- Asymptomatic infection - 5-10% of pre-schoolers and 65% of adults have antibodies
- Erythema infectiosum - most common
- Aplastic crisis - most serious consequence
- Fetal disease - mother-to-fetus trasmission may lead to featl hydrops and death from anaemia although most fetuses recover
Who is most effected by aplastic crises as a result of parvovirus B19?
Children with chronic haemolytic anaemia where there is an increased rate of cell turnover (e.g. sickle cell disease or thalassaemia) and in immunocompromised children (e.g. malignancy) who do not have an antibody response to neutralise the infectious agent.
What is the management of erythema infectiosum and what is the prognosis?
No specific treatment required
School exclusion not required - child not infectious once rash appears
Prognosis:
- Child feels better as the rash appears
- Rash peaks after a week then fades
- For a few months afterwards, a warm bath, sunlight, heat or fever will trigger a recurrence of bright red cheeks and the rash itself.
- Adults may get acute arthritis
What is shown?
How does the measles rash differ from roseola rash?
Roseola infanum shown
Roseola starts on the torso and spreads outwards
What is this called? (accompanies a maculopapular rash)
Nagayama spots on the uvula and soft palate
Occurs in roseola infantum
How long is a person with chickenpox infectious? Is schol exclusion necessary?
Infectivity = 4 days before rash, until 5 days after the rash first appeared*
School exclusion: NICE advise that the most infectious period is 1–2 days before the rash appears, but infectivity continues until all the lesions are dry and have crusted over (usually about 5 days after the onset of the rash).
What are the clinical features of chickenpox?
Fever initially
Itchy rash starting on the head/trunk before spreading - macular then papular then vesicular.
Mild systemic upset
Describe the rash in chickenpox. What does it mean if new lesions keep appearing beyond day 10?
Macular –> papular –> vesicular –> pustular –> crusting
50–500 lesions start on head and trunk, progress to peripheries but may be just a few lesions
Appear as crops of papules, vesicles with surrounding erythema and pustules at different times for up to one week.
Lesions may occur on the palate.
Itchy and scratching; may result in permanent, depigmented scar formation or secondary infection.
New lesions appearing beyond 10 days suggest defective cellular immunity
What is seen on this post-varicella pneumonia CXR?
Chest x-ray showing miliary opacities secondary to healed varicella pneumonia.
Multiple tiny calcific miliary opacities noted throughout both lungs - these are of uniform size and dense suggesting calcification.
There is no focal lung parenchymal mass or cavitating lesion seen. The appearances are characteristic for healed varicella pneumonia.
What does the distribution of this rash suggest?
Herpes zoster (shingles) in a child.
Distribution is along the S1 dermatome.
If recurrent or multidermatomal then suggests primary or secondary T cell immune defect
How does hand, foot and mouth disease present?
Mild systemic upset (sore throat, fever, myalgia)
Oral ulcers initially which are yellow surrounded by red haloes
Painful vesicles on hands, feet, mouth, tongue, buttock then appear and last 7-10 days (start as 2-5 mm erythematous macules but rapidly progress to grey vesicles with an erythematous base)
It is very contagious and typically occurs in outbreaks at nursery
E71 sometimes causes vomiting
What are the clinical features of rubella?
Prodrome, e.g. low-grade fever or none
Rash: maculopapular, initially on the face/behind ears before spreading to the whole body, usually fades by the 3-5 day
Lymphadenopathy: suboccipital and postauricular
