Infection Flashcards
List common antibody deficiency disorders
- X linked agammaglobulinaemia (brutons disease).- lack of B cells
- combined variable immunodeficiency - lack of IgG production
- IgA deficiency increased resp infections and allergies
- ataxia telangiectasia
features of ataxia telangiectasia
- recurrent resp infections
- ocular and facial telangiectasia
- progressive cerebellar ataxia
- increased leukaemia and lymphoma risk
describe omenn SCID
= exaggreated inflammatory response cause of oligclonal T CELLS
severe inflammation of skin - generalised erythroderma, alopecia, no eyelashes
lymphadenopathy
hepatosplenomegaly
chronic diarrhoea
present in 1st few weeks of life
describe wiskott aldrich syndrome
- eczema
- thrombocytopenia - bleeding, bruising
- recurrent infections - HSV, EBV
- malignancy
X linked disease , affects males
features of IgA deficiency
most common immunodeficiency
recurrent upper resp tract infections age >4 y/o
increased allergies
otitis media common
features of measles infection
infectious 7 days after exposure
prodrome: low grade fever, cough, coryzal, KOPLIK SPOTS (in buccal mucosa) , conjunctivitis
eruptive: macular rash starts behind ears and hairline and spreads, fever
diagnosis of measles
salivary sample for IgM measles
notify public health within 24 hours and they will contact trace
complications of measles
otitis media
interstitial pneumonitis
acute demyelinating encephalitis
sub sclerosing pan=encephalitis
deafness
myocarditis
presentation of mumps
fever
malaisea
parotitis - swelling and pain in both parotids
complications of mumps
orchitis
meningitis
encephalitis
diagnosis of mumps
salivary IgM
PCR
mumps specific antibodies
treatment consideration in severe mumps
ribavirin (anti viral)
varicella zoster type of virus
double stranded DNA virus
features of chicken pox
infectious 24 hours before rash
prodrome fever and malaise
erythematous itchy, widespread rash (macular -> papular -> vesicles -> crust)
moct common neurological complication = acute cerebellitis
describe the secondary infection of varicella zoster
SHINGLES!!
pain and tenderness in dermatome
vesicular rash in dermatomal distribution
ramsay hunt = vesicles in external ear (facial nerve)
management of immunocompromsied pts or babies exposed to varicella zoster
IV zoster immunoglobulin
following varicella exposure in immunocompromised OR babies born to mothers to have had chicken pox 5 days before delivery - 2 days after
or oral aciclovir for 7-14 days
management of unwell/ immunocompromised pts with varicella
IV aciclovir
and to neonates with delivery exposure
type of virus in slapped cheek syndrome
PARVOVIRUS B19
‘5th disease’
single stranded DNA virus
presentation of parvovirus/ slapped cheek
2-5 days of prodromal illness
erythematous cheeks with peri oral sparing
erythematous maculopapular rash on trunk and extremities (fades with lacy reticular rash)
can go back to school 1 day after rash appeared
complications of parvovirus
aplastic crisis in chronic haemolytic disease
aplastic anaemia -> bone marrow suppression
arthritis
congenital infection
presentation of EBV
fever
pharyngitis
cervical lymphadenopathy
malaise
maculopapular rash (worsens with penicillin)
hepatitis
splenomegaly(50%) and hepatomegaly (30%)
Increased risk of burkitt lymphoma
type of cell EBV infects
B lymphocytes
human herpes virus 4
diagnosis of EBV
monospot test - heterophile antibodies
blood film - atypical lymphocytosis
EBV antibodies - raised IgM and IgG
raised AST and ALT
type of virus cytomegalovirus
herpes virus 5
double stranded DNA virus
cytomegalovirus congenital presentation
blueberry muffin rash
symmetrical IUGR
hearing loss ***
microcephaly
congenital cataracts
diagnosis of CMV
PCR
serology
types of malaria
- P.falciparum ** - 75% cases, 10-28 days after bite
- P.vivax - asia, south ameria, africa (west africans resistent)
- P.ovale - west africa, west pacific
pathophysiology of malaria
- parasite carried by mosquito and transmission via bite from female anopheles mosquito
- sporozoites travel in blood stream to liver
- develop into schizonts (hypnozoites = dormant p.vivax and p.ovale) and rupture and release merozoites
- merozoites infect red blood cells (use duffy blood group antigens) where they mature and replicate
- RBC rupture and release more merozoites so parasite level increases
presentation of malaria
fever
malaise, sweats
pallor - anaemia
abdo pain, diarrhoea and vomiting
jaundice
hepatosplenomegaly
complications of malaria
- anaemia
- hypoglycaemia
- metabolic acidosis
- acute tubular necrosis
- DIC
- nephrotic syndrome
- resp distress from ARDS
diagnosis of malaria
- thick and thin blood films
thick = parasite detection, large volume of blood
thin = species detection
parasitaemia >2% = severe - malaria antigen testing = rapid, first test
prophylaxis for malaria
atovaquone and proguinail
mefloquine *
treatment of malaria
malarone * - proguanil and atovaquone
treatment of severe malaria
IV quinine + IV clarithromycine
exchange transfusion if >10% parasitaemia
type of bacteria Listeria
gram positive anaerobic bacteria
transmission from contaminated food (deli meats, cold cut)
can cross blood brain barrier
treatment of listeria
ampicillin or amoxicillin +/- gentamicin
cause of lyme disease
Borrelia burgdorferi (spirochere) spread by Ixodes tick
presentation of lyme disease
- erythema migrans ‘bulls eye’ rash
- disseminated disease - flu, neurological disease (facial palsy 15%, meningism), myopericarditis (cardiac disease RARE), lymphocytomas, AV or 1st degree heart block
- late stage - arthritis, acrodermatitis chronica atrophicans
Diagnosis of lyme disease
- ELISA test -> if positive, immunoblot test *
- IgM and IgG
management of lyme disease
doxycycline for 21 days
(if <12 y/o, amox or azithromycin)
cause of impetigo
streptococcus pyogenes (group a strep) and staph aureus
presentation of impetigo
honey coloured crusting and vesicles
pruritis
around face and mouth
presentation of toxic shock syndrome
high fever
hypotension, multi organ dysfunction
generalised erythematous rash ‘sunburn’
desquamation over 1-2 weeks
altered mental state
investigations of toxic shock
- blood cultures
2, FBC - thrombocytopenia - U&E - creatinine 2 x normal
- LFT - bilirubin 2 x normal
- CK - 2 x normal
management of toxic shock syndrome
1st line = clindamycin
Intestive care support
IV IG
cause of scabies
parasitic mite sacroptes scabei
transmitted by 10-15 mins skin contact
presentation of scabies
itching
rash 4-6 weeks after infestation - vesicular, around groin etc
diagnosis of scabies
skin scraping and dermatoscope
management of scabies
permethrin 5% cream and treat all members of household and sexual partners in last month
wash all bedding/ clothing/ towels at 60 degrees
presentation of congenital toxoplasmosis
microcephaly
hydrocephalus, intracranial calcifcations - need MRI HEAD
chorioretinitis
developmental delay and epilepsy
management of immunocompromised patients for toxoplasmosis
pyrimethamine + sulfadiazine + folic acid for 4-6 weeks
list the diseases protected against in the 6 in 1 vaccine
diptheria
tetanus
polio
pertussis
hep B
h.influzena type B
prophylaxis management if non immunised/ partially immunised close contact of pertussis
clarithromycin
vaccines at 2 months old
6 in 1 vaccine
Men B
rotavirus oral
vaccines at 3 months old
6 in 1 vaccine
penumococcal 13
rotavirus oral
vaccines at 4 months old
6 in 1 vaccine
Men B
vaccines at 12 months old
Men C
pneumococcal vaccine
MMR - measles, mumps , rubella
h. influenza B
vaccine at 3 years 4 months
DTap, / IPV
MMR
vaccine at 12-13 y/o
Human papillomavirus - types 16 and 18 cancers
genital warts HPV type 6 and 11
side effect: bronchospasm
vaccine at 14 y/o
tetanus, diptheria and polio
meningococcal group A,C,W,Y
list live vaccines
BCG
MMR
rotavirus
yellow fever
influenza
oral polio
varicella
common causes of c.diff
cephalosporins
lincomycin, clindamycin
ampicillin, amoxicillin
3-4 weeks after abx course
screening test for c.diff
glutamate dehydrogenase
treatment of c.diff
1st line = vanocmycin
2nd line = fidoxamicin
3rd line = IV metronidazole
cause of scarlet fever
group A streptococcus
presentation of scarlet fever
symptoms 1-7 days after being infected
sandpaper rash
red tongue ‘strawberry tongue’
fever
sore throat
presentation of leptospirosis
contact with contaminated water
jaundice
influenza like illness
renal disease -> weils disease
defintiion of periodic fever syndrome
unexplained fever in >3 episodes in 6 months at least 7 days apart
rise in IgD
describe giardia infection
acute diarrhoea
vomiting
very dehydrated
management of giardia
- hydration
- metronidazole
can lead to malabsorption from partial villous atrophy
features of cholera
‘rice water ‘ diarrhoea -> extremely dehydrated
50% die if untreated
desribe dengue
fever + rash +arhralgia
at risk of haemorrhagic fever
transmitetd by aedes mosquito
describe presentation of visceral leischmaniasis
ulcers with hyperpigmented scars
splenomegaly
hepatomegaly
anaemia
management of visceral leischmaniasis
sodium stibogluconate + amphotericin
describe brucellosis infection
unpasterised dairy products in Mediterranean, middle east
fever, headache, sweating, anorexia, papular rash
describe schistosomiasis infection
presents 4 weeks after swimming in affected water - asia, lake malawi, south america
painless haematuriea
itchy rash
management of schistosomiasis
detect by urine under microscope
praziquantel
describe gell + coombs classification type 1
IgE mediated
e.g. anaphyalxis, asthma, hayfever, eczema
describe gell + coombs classification type 2
cyctoxic antibody
e.g. goodpastures, rheumatic heart disease
describe gell + coombs classification type 3
immune complexes
e.g. post strep glomerulonephritis, lupis
describe gell + coombs classification type 4
T cell mediated
e.g. mantoux, contact dermatitis, chronic or acute transplant rejection
describe gell + coombs classification type 5
receptor mediated autoimmune e.g. graves, myasthenia gravis
inheritance of severe combined immunodeficiency syndrome
usually autosomal recessive *
ADA deficiency (10-15%) - X linked causes deficiency purine salvage
presentation of SCIDS
present early (6 months old) with severe recurrent life threatning infections
e.g. bacterial pneumonias, RSV, CMV, adenovirus
diarrhoea and faltering growth
BCG related complications e.g. abscess
skin rashes
candidiasis infections
diagnsosis of SCIDS
- lymphopenia
- CXR - absent thymus shadow
- low igG, igA, igM (all antibody subsets low)
management of SCIDS
- antimicrobial prophylaxis e.g. co-trimoxazole, acicvlovir, itraconazole
IgG replacement
haematopoietic stem cell transplant - only cure ! otherwise likely die by age of 2
cause of hypogammaglobunlinaemia
most common immune deficiency
X linked
mutation in BTK gene (Xq21.33-q22) - Involved in B lymphocyte differentiation and maturation -> failrue to produce B cells and Ig heavy chain rearrangement
presentation of hypogammaglobinaemia
severe, recurrent resp (bacterial) infections in infant BOYS
e.g. s.pnuemoniea, staphylococcus, moraxella, h.influenza
persistent diarrhoea
faltering growth
management of hypogammaglobulinaemia
- low or absent CD19 lymphocytes (normal T cells)
- annual LFTS
- IV immunoglobulin and antibiotics
cause of chronic granulomatous disease
X linked form (gp96phox deficiency) = 2/3 cases
other forms autosomal recessive
increase with consanguinity
phagocytes lack abaility to kill bacteria which causes granulomas formed by dysregulated inflammatory response
presentation of chronic granulomatous disease
presents under 5 y/o
recurrent pneumonia (burkholderia, aspergillus, pseudomonas)
deep seated infections and abscesses
osteomyelitis at multiple sites
poor growth
skin abscesses
investigations for chronic granulomatous disease
- dihydrorhodamine neutrophul burst assay - absent
- nitroblue tetrazolium test - negative
inheritance of hereditary angioedema
autosomal dominant
presentation of hereditary angioedema
episodic attacks starting in 1st decade of life precipitated by trauma, stress, menstruation, COCP and ACE-I
abdominal pain
rash - erythema marginatum
swelling of lips and mucosa
non pitting oedema of hands and feets
symptoms nOT relieved by adrenaline / anti histmine
diagnosis of hereditary angioedema
reduced C4 level
C1INH level reduced (C1 esterase inhibitor)
to prevent attacks in hereditary angioedema
anti fibrinolytics e.g. transexamic acid
purified C1INH from human plasma
monoclonal antibody
how does mantous test work
intradermal tuberculin
measure induration at injection site 72 hour after
most common form of shigella
shigella sonnei most common in developed world, milder disease
deficiency in which complement in meningitis
C5- C9 deficits
(terminal complement deficiecny suspceptible to meningitis)
commonest cause of nec fasc
group a strep
presentation of yellow fever
south and central america
severe flu like illness, fevers -> recovery and feel better -> severe fever again, jaundice =, hepatomegaly, bleeding gums, malaena
common causes of myocarditis
coxsackie B in england
trypanosoma cruzi - worldwide, ‘chagas disease’
dose of adrenaline in anaphylaxis
1:1000
>12 y/o - 500 micrograms
6-12 y/o - 300 micrograms
6 yo - 150 micrograms
how can tinea present
- kerion - boggy swelling on head, red, alopecia surrounding
- extensive scaling with hair loss
- black dots where hair follicles fallen off
- widespread pustules with lymphadenopathy
- patchy hair loss
diagnosis of wiskott aldrich syndrome
low IgG and IgM
high total IgE and IgA
decreased number and function of T cells
chemical mediators in anaphylaxis
- surface bound IgE on mast cells and basophils interact with specific allergen
- mast cell degranulation and mediator release inc:
- histamine - produces symptoms of anaphylaxis (causes coronary artery vasoconstriction and increased vascular permeaility)
- tryptase - released in inoculation anaphyalxis e.g. contrast, insect stings
incubation period for chicken pox
10-20 days
features of congenital varicella syndrome
skin scarring
limb hypoplasia
microcephaly, seizures, developmental delay
chorioretinitis, cataracts
hydronephrosis
neurogenic bladder
swallowing difficulties
90% of food allergens include…
peanut - 80% persist to adulthood
cows milk
egg
tree nut and seeds
fish
shellfish
soya
wheat
how does IgE allergy present
immediate after consumption of allergen
angioedema - lips, tongue, eyes
acute urticaria
vomiting, diarrhoea
wheeze, cough, congestion
how is IgE allergy diagnosed
- food specific igE
- ‘skin prick’ testing - increased size of wheal = increased incidence of allergy
how does non IgE allergy present
2-72 hours after encountering allergen
pruritus
erythema
GORD
blood/ mucus in stool
abdo pain
faltering growth
how is non igE allergy diagnosed
trial elimination of food
which vaccine to avoid in hIV
BCG
how does adrenaline work in anaphyalxis
- alpha adrenergic - vasoconstriction to increase blood pressure and reduce plasma extravasation
- beta adrenegric - cause bronchoconstriction in the airways
- mast cell stabilisation - prevents further degranulisation and release of vasoactive materials
common cause of encephalitis
herpes simplex virus
treatment for whooping cough
azithromycin (or clarithromycin < 6 months old)
cholera vaccination
3 doses orally to children 2-5 y/o
2 doses if 6-16 y/o
oral inactivated cholera vaccine (Dukoral)
how is the complement cascade activated
IgA activates alternative pathway
IgG and IGM activate classical pathway
diagnosis of anaphylaxis
mast cell tryptase levels 1.5 hours after anaphylaxis
IgE levels if in clinic
