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Infectious diseases in childhood


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VZV in an immunocompromised individual
spread to lungs and liver in 30-50% of children with T cell deficiency mortalilty 15% (0.1-4% in healthy) rapidly progressive
flat and impalpable
stages of Measles infection
incubation - 8-12 days with no symptoms prodrome - malaise, fever, cough, coryza, conjunctivitis skin findings - within 2-3 days will see Koplik's spots (small red with central grey or blue-white specks). After 5 days see erythematous maculopapular rash starting at head and spreading caudilly lasting 4-5 days ** infective from prodrome
circumscribed, elevated lesions
diagnosis of measles
virus isolation, during prodrome until day 2 of rash PCR Measles IgM from 3 days after onset of rash 4x increase in haemaggluntination inhibition antibodies over 2 weeks
agent of infection in Measles
elevated lesions containing a purulent exudate
petechiae and other haemorrhagic spots
cannot be blanched by compression and may be flat or raised. purpura if over 0.5cm in diameter
vesicular rashes
varicella zoster virus herpes sinplex virus hand, foot and mouth disease impetigo molluscum contagiosum dermatitis herpetiformis Stevens-Johnson syndrome
circumscribed, elevated, fluid-filled, and normally less than 0.5cm in diameter
agent of infection in chicken pox
varicella zoster virus
stages of VZV
incubation - 10-21 days prodrome - mild fever, malaise, anorexia, occasionally scarlatiniform or morbilliform rash pruritic rash (characteristic) follows the next day: - starts on trunk and spreads peripherally - begins as red papules and develops rapidly into teardrop vesicles (1-2mm) - vesicles become cloudy, break and form scabs - crops of lesions occur so there are several stages of lesions present - vesicles often involve mucous membranes ** infectious from 24-48 hrs prior to onset of rash up until lesions crust
VZV rash
vesicular lesions at different stages (red papules > teardrop vesicles > crusted) predominantly TRUNCAL distribution present in hair line
Herpes zoster (VZ reactivation) uncommon in under 10s begins with pain along a dermatome, fever and malaise Note: VZV damages nerve and DR ganglia more than HSV, get more pain and neural dysfunction in adults but almost never in kids crops of vesicles appear along the dermatome at different stages of evolution
Diagnosis of VZV
clinical picture Lab diagnosis only required for atypical presentations (immunocomp), distinguishing between HS and HZ to determine immune status in high risk people or their families (preg women, immunocomp) Ag detection, culture, genome detection, serology
complications of VZV
-bacterial superinfection - cerebellitis, encephalitis, pneumonitis, hepatits, arthritis (uncommon in kids, 50x more common in adults)
maternal chickenpox in pregnancy
3 possible outcomes to foetus: 1. during the first 5 months pregnancy may be followed by congenital varicella syndrome 2. during the second and third trimester may lead to appearance of zoster in a healthy child 3. 48 hrs before - 5 days after delivery may cause severe neonatal disease. Give VZIG to infant!!!!!
Congenital Varicella
skin scars (80%), eye defects (60%), limb abnormalities (70%), also prematurity, LBW, cortical , low IQ, poor sphincter control, early death (29%)
VZV treament
infection in neonate, immunocompromised or complicated chickenpox requires high dose IV antiviral therapy Aciclovir, valavivlovir, famciclovir if PO therapy indicated
VZV Vaccine
Live attenuated Oka strain 95% of kids 1-12 develop immunity after single dose, 78% of those >13 after single dose, 99% after two doses >95% effective against severe disease, 70-90% mod, 10-30% mild Need booster dose to prevent break through VZV after 10 yrs
orolabial disease, HSV keratitis, encephalitis Severe disease in immunocomp vertical transmission to newborn Genital infection in kids suggestive of sexual abuse or activity (but not always the case!!)
HSV stomatitis
1-30% of seropositive kids peak at 9months to 3yrs febrile, cervical/submandibular adenopathy refuses to eat
Herpetic whitlow
finger/nail involved lasts 14-21 days in healthy, severe in immunocomp associated with gingostomatitis recurrence 20%, less common in childhood AVOID surgical drainage
Neonatal HSV
skin, eye and mouth lesions. Encephalitis, disseminated infection, pneumonitis. 4/100,000 requires IV aciclovir 25% mortality rate!! 85% due to passage through infected birth canal (most women unaware they have herpes) Greatest risk genital HSV type 1 or 2 in late pregnancy
HSV diagnosis
Why? PBS for genital infection, ensure correct diagnosis (atypical presentation, neonates and immunocomp, therapy, complications and prognosis How? - viral isolation - direct Ag detection PCR (esp CSF) type specific antibody in HSV encephalitis do neuroimaging and EEG!
Hand, foot and mouth disease
cause by enteroviruses, most commonly Coxsackie type 16 papular-vesicular eruptions of mouth (gums NOT involved unlike HSV), hand, feet and sometimes buttocks
red macule that becomes vesicular vesicles burst to leave a honey coloured crust both streptococcal and staphlyococcal impetigo occur commonly around the mouth but can occur elsewhere highly contagious!
Maculopapular rashes
measles, rubella, scarlet fever, kawasaki disease, fifth disease, roseola infantum, other viral infections such as enteroviruses and adenoviruses
Mumps agent
RNA paramyxovirus spread by droplets and saliva
stages of Mumps
incubation - 14-21 days prodrome - fever, headache, malaise, anorexia Then painful parotid swelling (first unilateral then bilateral in 70%) complete recovery is the norm
complications of mumps
orchitis +/- infertility arthritis meningitis pancreatitis myocarditis
management of Mumps
rest, paracetamol, syrup for high fever or severe discomfort
Rubella agent
RNA togavirus
postnatal vs congenital rubella
congenital rubella devestating, during first 20 weeks of pregnancy postnatal rubella is often absent of symptoms
stages of rubella in kids
prodrome - 21 days, usually no symptoms Fine, erythematous maculopapular discrete rash for 5 days. Commences on face then trunk then limbs Posterior and cervical LN enlargement. Slight fever. Transient polyarthritis common in adolescents. Rash develops more quickly and leaves faster than measles. Encephalitis and thrombocytopenia rare outcomes. ** infective 5 days before and 5 days after rash
tests for rubella
rubella specific IgM rising titres of rubella anitbody via haemaglutin inhibition and ELISA isolation of rubella virus in infants of only a few months
Scarlet Fever agent
Group A Strep
Features of scarlet fever
dark red and punctiform rash, prominent on neck and in major skin folds. Distinctive feature is circumoral pallor as a result of the rash sparing. Desquamation on face then trunk and limbs. Associated with inflammation of tongue (white and red strawberry tongue) Rx with penicilin
Kawasaki disease
Unknown aetiology Prolongled fever. Discrete red maculopapules seen on the feet, around the knees and in the axillary and inguinal creases. swelling of hands desquamation of hands and feet occurs later ** risk of coronary artery aneurysms
Fifth disease
parvovirus B19 starts with mild fever or rash Rash in two phases: -cheeks appear red and flushed (slapped) - then: lacy, maculopapular rash develops 1-2 weeks later, predominantly over arms and legs which appears lace-like as it fades. Assoc. with joint aches.
Risks of Fifth disease
Risk to pregnant women (hydrops fetalis, fetal death) haematological malignancy, HIV infected, haemaglobinopathies - chronic anaemia
Diagnosis of fifth disease
PCR of blood, parvoviris IgM
Roseola Infantum
HHV-6 comences with high fever for 3-4 days with onset of rash, but child looks well (unlike in measles) Widespread maculopapular rash mainly on trunk, discrete lesions Associated with febrile convulsions during prodrome. Risk of CNS infections in immunocomprimised
Meningococcal infection
Early maculapapular rash on the trunk, may blanch in some cases. Then characteristic petechial or purpuric rash anywhere on body. NON BLANCHING.
Major clinical presentations of meningococcal disease
meningitis, septicaemia or both. Most deaths occur with septicaemic form. Meningitic form presents with fever, vomiting, headache and neck stiffness. Arthritis, pericarditis and pleural effusions may occur 5-10 days after acute infection (autoimmune)
Diagnosis of meningococcal
-recovery of N.meningitidis from blood, petechial lesions or CSF - meningococcal DNA via PCR in blood and CSF - serology may confirm diag retrospectively - blood count: polymorphonuclear leukocytosis. Neutropenia present in severe disease and poor prognostic sign. DIC with thrombocytopenia my be present.
Management of meningococcal
PROMPT: IM penicillin, 3rd gen cephalosporin +/- resuscitation
Prophylaxis of meningococcal
to family and close contacts of patient. Rifampicin (not if preg). Ceftriaxone IMI or oral ciprofloxacin are alternatives. Meningococcal C vaccine introduced but NOT major serotype in early childhood. Mortality of 10%
signs of infection in the newborn
fever, lethargy, anorexia, apnoea
Action to take with a febrile newborn
cultures of blood, CSF and urine, then start of empirical IV antibiotics
Neonatal sepsis types
Early onset - onset in first 48-72 hours of life. Usually present with fulminant multisystem disease with pneumonia. Late onset - onset greater than three days. Present as slow progressive focal infections, most commonly meningitis. EONS 10 fold less incidence than LONS but higher mortality rate
Maternal risk factors for neonatal sepsis
- spontaneous onset of preterm labour <37 weeks - prolonged rupture of membranes >18 hours - maternal carriage of group B strep - maternal fever >37.5 - mother has had previous baby with group B strep infection
Group B strep
0.5-0.75/100 cause of: meningitis, septicaemia, pnuemonia, focal infections (osteomylitis, septic arthritis, cellulitis) Intrapartum antibiotics given to maternal carriers to reduce incidence
Congenital CMV infection
1:200, commonest congenital infection 10% symptomatic at birth - sensorineural hearing loss, severe motor deficit, mental retardation, chorioretinitis, seizures, dental defects, herniae. Asymptomtic infant may have late onset hearing loss
Investigations and treatment of suspected sepsis in newborn
Ix: - WCC is unreliable - neutrophil count abnormal in 2/3s - platelets low is indicator of severe bacterial sepsis, fungal sepsis or congenital infection Microbiol: - blood culture, CSF, urine, tracheal aspirates, skin lesion swabs - gastric aspirates Rx: empirical antibiotics once cultures taken. If no organisms isolated after 48-72 hours, advisable to stop antibiotics to avoid resistant colonisation.
Empiric antibiotic in neonates
ampicillin and gentamicin

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