PAEDS - genetics, infectious diseases Flashcards
what is turner’s syndrome?
how is it denoted?
- affects females
- presence of only one X chromosome
- 45, XO or 45, X
what causes turner’s?
a nondisjunction/sporadic mutation meaning there is only 1 or a partially missing X chromosome
NOT INHERITED
RFs for Turner’s
no known RFs
features of Turner’s and some associated conditions (3)
- primary amenorrhoea
- short stature
- widely spaced nipples
- webbed neck
- high arched palate
other = short 4th metacarpal, hypothyroidism, horseshoe kidney, heart defects
what is the most common renal abnormality associated with turner’s?
horseshoe kidney
what heart defect is associated with turner’s?
bicuspid aortic valve (most common)
coarctation less common
when may Turner’s be identified? how?
- suspected on prenatal USS (horseshoe kidney)
- if suspected can do amniocentesis/chorionic villus sampling
postnatal investigations for turner’s
1st line and GS
1st = bloods - raised FSH/LH (due to ovarian insufficiency)
GS = karyotyping
why is there high levels of FSH and LH in turner’s?
ovarian failure > no negative feedback from oestrogen > FSH and LH continue to rise
once a diagnosis of Turner’s has been made, what investigations can be done to check for other problems? (4)
- echo
- renal tract USS (renal tract)
- pelvis USS (ovaries)
- DEXA scan
ddx for Turner’s
William’s
gonadotropin deficiency e.g. Kallman’s
management of Turner’s including medications
- MDT
- hormone replacement therapy
- oestrogen
- progesterone
- growth hormone
when would oestogren and progesterone be started and stopped in a patient with Turner’s?
- started at age 11
- stopped around 50
main complication of Turner’s
name some other complications? (4)
main = aortic dilatation and dissection
other = autoimmune thyroiditis, Crohn’s, horseshoe kidneys, cystic hygroma
what is William’s syndrome?
a neurodevelopmental disorder caused by a microdeletion on chromosome 7
cause of William’s
random deletion around conception (NOT inherited)
signs and symptoms of William’s
- starburst eyes
- short stature
- long philtrum (upper lip)
- very sociable, trusting
- mild learning disability
what metabolic change is William’s associated with after birth?
transient neonatal hypercalcemia
which heart defect is William’s associated with?
supravalvular aortic stenosis
gold std investigation for William’s
genetic testing (FISH)
ddx for Williams
- Turner’s
- ADHD
- Noonan syndrome
management for Williams (3)
- MDT
- monitor with echos, BP
- low calcium diet and avoid calcium supplements
4 associated conditions with Williams
- supravalvular aortic stenosis
- ADHD
- HTN
- hypercalcemia
what causes kawasaki’s
a type of medium vessel vasculitis
when does kawasaki disease most commonly present
<5
who is kawasaki disease more prominent in
Japanese and Afro-Caribbean children
signs and symptoms of kawasaki disease
CRASH AND BURN
C - conjunctivitis
R - rash
A - adenopathy (swollen glands)
S - strawberry tongue
H - hands: palmar erythema and swelling
HIGH FEVER (39) >5 days (resistant to antipyretics)
investigations for kawasaki
clinical diagnosis but must do ECHO for aortic aneurysm
complication of kawasaki disease
coronary artery aneurysm
ddx for kawasaki
scarlet fever
management of kawasaki disease
- high dose aspirin
- IV immunoglobulins
NOTIFIABLE DISEASE
what causes measles?
RNA paramyxovirus
when is measles infectious
from when sx first appear to four days after onset of rash
measles was common prior to… why?
1968 - MMR vaccine intro
RFs for measles (3)
- unvaccinated
- immunosuppression
- recent contact w infected person
presentation of measles
- prodrome lasting a few days - fever, coryzal
- koplik spots in mouth (red/white)
- maculopapular erythematous rash starting from behind ears and descending to rest of body
- fever >39
investigations for measles
contact health protection team
they will send oral fluid testing kit for IgM/IgG and/or viral RNA testing
management of measles
how long should the child be off school?
- notify PHE
- self-limiting disease so supportive management
- off school for 4 days from onset of rash
complications of measles - what’s most common?
most common = otitis media
others - pneumonia, encephalitis, febrile convulsions, myocarditis
what causes rubella
togavirus
RFs for rubella (2)
- unvaccinated/unclear imms hx
- developing countries
presentation of rubella
- prodrome - low grade fever which resolves
- then RASH - beings in face, spreads down body
- palatal petechiae
- lymphadenopathy - suboccipital and postauricular
general = headache, sore throat
investigations for rubella
- normally clinical
- if need to confirm then bloods (IgM) and viral PCR
management of rubella
how long should the child be kept off school?
- notifiable disease!
- supportive tx
off school until at least 5 days after rash onset
what causes chickenpox
varicella zoster virus
what is chickenpox?
a primary varicella zoster infection
presentation of chickenpox
- RASH
- starting on trunk/face and spreading all over
- widespread, erythematous, raised, vesicular blistering lesions
- itchy - fever
- general fatigue/malaise
what is the life cycle of the rash in chicken pox?
macular > papular > vesicular > crusted
management of chickenpox in <14
when should children stay off school until?
self-limiting…
1. trim nails
2. calamine lotion
3. consider antihistamine e.g. chlorpheniramine
off school until all lesions crusted
prophylactic tx of chickenpox in immunocompromised/newborns with peripartum exposure
varicella zoster immunoglobulins (VZIG)
management of chickenpox in immunocompromised/children >14
acyclovir
what med shouldnt be given in chicken pox? why
NSAIDs - risk of necrotising fasciitis
what is molloscum contagiosum caused by?
MCV - molloscum contagiosum pox virus
incubation period of molloscum contagiosum
2-8 weeks
presentation of molloscum contagiosum
- firm, smooth papules with small depression in centre (umbilicated), white/pink/brown
- in moist areas - armpit, groin, genitals
management of molloscum contagiosum
when does it resolve?
self-limiting - can use emollient/mild topical steroid for itching
resolves by itself in 18 months
causative agent of roseola infantum
human herpes virus 6
congenital heart defect in fragile X
mitral valve prolapse
fragile x
- what mutation
- who
- FMR1 gene (trinucleotide repeat on x chromosome)
- males
presentation of fragile X (6)
- delay in S&L development, cognitive difficulties
- long, thin face
- big ears
- autism, ADHD
- microorchidism
- hypermobile joints
Edward’s syndrome is trisomy…
18 (three copies of chromosome 18 rather than two)
pathophys and prognosis of
a) full edward’s syndrome
b) mosaic edward’s
c) partial edward’s
a) extra chromosome 18 present in all cells, v severe and often die before born
b) extra chromosome 18 in just some cells, most babies live for a year
c) only a section of the extra chromosome 18 is in cells, least severe
presentation of edward’s syndrome
- micrognathia (jaw undersized)
- low-set ears
- ROCKER-BOTTOM FEET
- overlapping fingers
results of HcG and PAPP-A bloods in screening for edward’s and patau’s
low beta-HCG, low PAPP-A
features of down’s syndrome (8)
- short stature and neck
- prominent epicanthal folds
- upward sloping parebral fissures
- single palmar crease
- bradycephaly (small head with a flattened back)
- hypotonia
- conductive hearing loss/cataracts
- flattened nose bridge
screening for DS
a) first-line tests, when and what do they involve?
b) results in DS
a) combo triple test
- 11-13 weeks gestation
- USS for nuchal translucency, maternal bloods for beta-HcG and pregnancy-associated-plasma-protein-A (PAPP)
quadruple test
- 14-20 weeks gestation
- maternal bloods: beta-HcG, AFP, serum oestriol, inhibin A
b) triple test - thickened nuchal (>6mm), high HcG, low PAPP
quad test - high HcG, low AFP, low oestriol, high inhibin A
GS antenatal screening for DS - when is this done?
only if risk score is greater than 1 in 150!
amniocentesis (AF biopsy) or chorionic villus (placental biopsy)
GS postnatal test for DS
bloods: QF-PCR test and G-banded analysis
cardiac cx in DS (3)
- tetralogy of fallot
- VSD/ASD/AVSD
- PDA
later life complications of DS (4)
- subfertility
- ALL
- hypothyroidism
- Alzheimer’s
causes of SJS
- NSAIDs
- allopurinol
- anti-epileptics e.g. carbamazepine, phenytoin, lamotrigine
- antibiotics e.g. penicillin
signs and symptoms of SJS
following starting a new medication…
- early flu-like sx
- RASH - red/purple, peeling, blistering
- MUCOSAL involvement - eyes, lips, mouth, pharynx, oesophagus, GI tract, kidneys….
- corneal ulceration, uveitis, blepharitis
- oesophageal strictures
- vaginal stenosis, penile scarring
what sign is positive in SJS and SSSS?
Nikolsky’s sign - epidermal layer sloughs off when pressure applied
diagnostic ix for SJS and result
skin biopsy - keratinocyte apoptosis
management of SJS
- STOP causative drug
- transfer to burn centre/wound care
- conservative care - wound care, analgesia, fluids, nutrition
what organism causes scalded skin syndrome?
staph aureus
examples of infections preceding staph scalded skin syndrome?
- nappy rash
- impetigo
- cellulitis
- eye infection
pathophys of SSSS
- staph aureus produce epidermolytic toxins
- these toxins break down proteins holding skin together
presentation of SSSS
RECENT INFECTION…
- initially miserable, lethargic, fever
- tissue-paper skin with wrinkling
- then bullae in groin, armpits, orifices
- painful widespread rash resembling burn/scald
management of SSSS
- IV fluids
- systemic IV abx
which CHD is most associated with noonan syndrome?
pulmonary stenosis
patau syndrome is trisomy…
13
RF for patau syndrome
advanced maternal age
signs and symptoms of patau syndrome in utero
IUGR
signs and symptoms of patau syndrome at birth
- cleft lip and palate
- microphthalmia (small eyes)
- microcephaly
- polydactyly
- ear malformations, deafness
prognosis of patau syndrome
poor - unlikely to survive first few days of life
ddx of patau syndrome
edward’s syndrome (can both present with rocker bottom feet)
presentation of prader-willi syndrome
- obesity (constant insatiable hunger)
- hypotonia
- hypogonadism
