Infection Flashcards
Features of measles
Rash
Think of C’s, conjunctivitis, coryza,
“Koplik spots”.
2 week incubation
Features of meningococcal septicaemia
A petechial rash of sudden onset is associated with septicaemia
Treat urgently with antibiotic
Summary of thread worms?
Occurs after swallowing eggs in environment
Perianal itching, particularly at night
Girls may have vulval Sx
Asymptomatic in 90%
Apply Sellotape to perianal area send for microscopy to see eggs, but most pt’s treated empirically
Hygiene measures
Single dose of mebendazole for all members of household
Causes of meningitis?
<3mnths: GBS, e coli, Gr-, listeria monocytogenes
1mnth-6yrs: Neisseria meningitidis (meningococcus), s pneumonia, h influenzae
> 6yrs: Neisseria meningitidis, s pneumoniae.
Features of meningitis?
<3mnths, irritability, general lethargy, poor feeding + fevers.
Seizures
Photophobia, neck stiffness rare, high index of suspicion for meningitis in generally unwell infant
Non-blanching petechial rash.
Investigation for meningitis?
CI to LP: any signs of ↑ICP, focal neurological signs, papilledema, bulging of fontanelle, DIC, signs of cerebral herniation. Meningococcal septicaemia.
Blood cultures
PCR
Management of meningitis?
<3 mnths: IV amoxicillin + IV cefotaxime. Don’t give steroids.
> 3 mnths: IV cefotaxime/ceftriaxone.
Dexamethasone: if, frankly purulent CSF, CSF WBC >1000/ microlitre, ↑CSF WBCC with protein conc >1g/L bacteria on Gr strain.
Abx prophylaxis of contacts: ciprofloxacin
What is roseola infantum?
a common disease of infancy caused by the human herpes virus 6 (HHV6).
It has an incubation period of 5-15 days
typically affects children aged 6 months to 2 years.
Features of roseola infantum?
high fever: lasting a few days, followed later by a
maculopapular rash
Nagayama spots: papular enanthem on the uvula and soft palate
febrile convulsions occur in around 10-15%
diarrhoea and cough are also commonly seen
Other possible consequences of HHV6 infection
> aseptic meningitis
> hepatitis
School exclusion is not needed.
Paracetamol + ibuprofen
What is mumps?
caused by RNA paramyxovirus
tends to occur in winter and spring
Spread:
- by droplets
- respiratory tract epithelial cells → parotid glands → other tissues
- infective 7 days before and 9 days after parotid swelling starts
- incubation period = 14-21 day
MMR vaccine: the efficacy is around 80%
Features of mumps?
fever
malaise, muscular pain
parotitis (‘earache’, ‘pain on eating’): unilateral initially then becomes bilateral in 70%
fever disappears within 3-4 days
Management of mumps?
rest
paracetamol for high fever/discomfort
notifiable disease
Complications of mumps?
orchitis - uncommon in pre-pubertal males but occurs in around 25-35% of post-pubertal males. Typically occurs four or five days after the start of parotitis
hearing loss - usually unilateral and transient
meningoencephalitis
pancreatitis
Investigations of mumps?
Plasma amylase ↑ = pancreatic involvement
Pos salivary mumps IgM
Management of mumps?
No Tx, rest, paracetamol, notifiable disease.
Exclusion from school or work for 5 days of swollen glands
What is measles?
RNA paramyxovirus
spread by droplets
infective from prodrome until 4 days after rash starts
incubation period = 10-14 days
rarely seen in developed world following adoption of immunisation programmes
Features of measles?
prodromal phase = irritable,
conjunctivitis, fever
Koplik spots = typically develop before the rash, white spots (‘grain of salt’) on the buccal mucosa
rash = starts behind ears then to the whole body, discrete maculopapular rash becoming blotchy & confluent, desquamation that typically spares the palms and soles may occur after a week
diarrhoea occurs in around 10% of patients
Investigations for measles?
IgM antibodies can be detected within a few days of rash onset
Management of measles?
mainly supportive - simple analgesia
admission may be considered in immunosuppressed or pregnant patients
notifiable disease → inform public health
School exlcusion: 4 days after rash develop
Complications of measles?
otitis media: the most common complication
pneumonia: the most common cause of death
encephalitis: typically occurs 1-2 weeks following the onset of the illness)
subacute sclerosing panencephalitis: very rare, may present 5-10 years following the illness
febrile convulsions
keratoconjunctivitis, corneal ulceration
diarrhoea
increased incidence of appendicitis
myocarditis
Managing contacts of measles?
if a child not immunized against measles comes into contact with measles then MMR should be offered (vaccine-induced measles antibody develops more rapidly than that following natural infection)
this should be given within 72 hours
What is erythema infectiosum?
‘slapped cheek syndrome’
Common in children, rarer in adults, but more serious
Only spread to others 3-5 days before rash appears
Parvovirus B19
Features of slapped cheek syndrome?
↑temp
Runny nose + sore throat
Headache
Bright red rash, both cheeks, look as if been slapped.
Adults don’t usually get rash.
Few days later, lighter rash on chest, arms, legs, skin raised + itchy. Rarely involved palms + soles.
Complications of slapped cheek syndrome?
Child begins to feel better as rash appears + rash peaks after a wk then fades. For mnths after, bath, sun, heat, fever trigger recurrence of red cheeks + rash.
Management of slapped cheek syndrome?
Self limiting, better in 3wks. Paracetamol/ ibruprofen.
See GP: pregnant (miscarriage), sickle cell (aplastic crisis, supress erythroporesis for a wk) thalassaemia (severe anaemia), weakned immune system.
No school exclusion
Other presentations of parvovirus B19?
asymptomatic
pancytopenia in immunosuppressed patients
aplastic crises e.g. in sickle-cell disease
parvovirus B19 suppresses erythropoiesis for about a week so aplastic anaemia is rare unless there is a chronic haemolytic anaemia
hydrops fetalis
parvovirus B19 in pregnant women can cross the placenta in pregnant women
this causes severe anaemia due to viral suppression of fetal erythropoiesis → heart failure secondary to severe anaemia → the accumulation of fluid in fetal serous cavities (e.g. ascites, pleural and pericardial effusions)
treated with intrauterine blood transfusions
What is Scarlet fever?
a reaction to erythrogenic toxins produced by Group A haemolytic streptococci (usually Streptococcus pyogenes).
It is more common in children aged 2 - 6 years with the peak incidence being at 4 years.
spread via the respiratory route by inhaling or ingesting respiratory droplets or by direct contact with nose and throat discharges, (especially during sneezing and coughing).
Features of scarlet fever?
Incubation period of 2-4 days
fever: typically lasts 24 to 48 hours
malaise, headache, nausea/vomiting
sore throat - can appear 1-2 days after tonsillitis
‘strawberry’ tongue
rash:
> fine punctate erythema (‘pinhead’) which generally appears first on the torso and spares the palms and soles
> children often have a flushed appearance with circumoral pallor. The rash is often more obvious in the flexures
> it is often described as having a rough ‘sandpaper’ texture
> desquamination occurs later in the course of the illness, particularly around the fingers and toes
Diagnosis of scarlet fever?
a throat swab is normally taken but antibiotic treatment should be commenced immediately, rather than waiting for the results
Management of scarlet fever?
oral penicillin V for 10 days
patients who have a penicillin allergy should be given azithromycin
children can return to school 24 hours after commencing antibiotics
scarlet fever is a notifiable disease
Complications of scarlet fever?
otitis media: the most common complication
rheumatic fever: typically occurs 20 days after infection
acute glomerulonephritis: typically occurs 10 days after infection
invasive complications (e.g. bacteraemia, meningitis, necrotizing fasciitis) are rare but may present acutely with life-threatening illness
What is coxsackie virus?
Hand, foot, mouth
Caused by intestinal virus of picornaviruses (coxsackie A16 + enterovirus 71).
Very contagious
typically occurs in outbreaks at nursery
Features of hand, foot and mouth disease?
mild systemic upset: sore throat, fever
oral ulcers
followed later by vesicles on the palms and soles of the feet
Management of hand, foot and mouth disease?
symptomatic treatment only: general advice about hydration and analgesia
reassurance no link to disease in cattle
children do not need to be excluded from school
the HPA recommends that children who are unwell should be kept off school until they feel better
they also advise that you contact them if you suspect that there may be a large outbreak.
What is chicken pox?
caused by primary infection with varicella zoster virus.
Shingles is a reactivation of the dormant virus in dorsal root ganglion
Highly infectious
spread via the respiratory route
can be caught from someone with shingles
infectivity = 4 days before rash, until 5 days after the rash first appeared*
incubation period = 10-21 days
Features of chicken pox?
fever initially
itchy, rash starting on head/trunk before spreading. Initially macular then papular then vesicular then crust and fall off
systemic upset is usually mild
more sever in older children/adults
Management of chicken pox?
supportive
keep cool, trim nails
calamine lotion
school exclusion: NICE Clinical Knowledge Summaries state the following: 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).
immunocompromised patients and newborns with peripartum exposure should receive varicella zoster immunoglobulin (VZIG). If chickenpox develops then IV aciclovir should be considered
Complications of chicken pox?
secondary bacterial infection of the lesions -NSAIDs may ^ risk, single infected area/small area of cellulitis, invasive group A streptococcal soft tissue infections may occur > necrotising fasciitis
pneumonia
encephalitis (cerebellar involvement may be seen)
disseminated haemorrhagic chickenpox
arthritis, nephritis and pancreatitis may very rarely be seen
What is neonatal sepsis?
a serious bacterial or viral infection in the blood affects babies within the first 28 days of life.
Neonatal sepsis is categorised into early-onset (EOS, within 72 hours of birth) and late-onset (LOS, between 7-28 days of life) sepsis
account for 10% of all neonatal mortality
Male:female incidence 1:1
Incidence of neonatal sepsis: 1-5 per 1000 live births
Term neonates: 1-2 per 1000 live births
Late pre-term infants: 5 per 1000 live births
Birth weight <2.5kg: 0.5 per 1000 live births
Black race is an independent risk factor for group B streptococcus-related sepsis
Causes of neonatal sepsis?
The overall most common causes of neonatal sepsis are group B streptococcus (GBS) and Escherichia coli, accounting for approximately two thirds of neonatal sepsis cases
Early-onset sepsis in the UK is primarily caused by GBS infection (75%)
Infective causes in early-onset sepsis are usually due to transmission of pathogens from the mother to the neonate during delivery
Late-onset sepsis usually occurs via the transmission of pathogens from the environment post-delivery, this is normally from contacts such as the parents or healthcare workers
Infective causes are more commonly coagulase-negative staphylococcal species such as Staphylococcus epidermidis, Gram-negative bacteria such as Pseudomonas aeruginosa, Klebsiella and Enterobacter, and fungal species
Other less common causes include: Staphylococcus aureus Enterococcus Listeria monocytogenes Viruses including herpes simplex and enterovirus
Risk factors for neonatal sepsis?
Mother who has had a previous baby with GBS infection, who has current GBS colonisation from prenatal screening, current bacteruria, intrapartum temperature ≥38ºC, membrane rupture ≥18 hours, or current infection throughout pregnancy
Premature (<37 weeks): approximately 85% of neonatal sepsis cases are in premature neonates
Low birth weight (<2.5kg): approximately 80% are low birth weight
Evidence of maternal chorioamnionitis
Presentation of neonatal sepsis?
Respiratory distress (85%) = Grunting, Nasal flaring, Use of accessory respiratory muscles, Tachypnoea
Tachycardia: common, but non-specific
Apnoea (40%)
Apparent change in mental status/lethargy
Jaundice (35%)
Seizures (35%): if cause of sepsis is meningitis
Poor/reduced feeding (30%)
Abdominal distention (20%)
Vomiting (25%)
Temperature: not usually a reliable sign as the temperature can vary from being raised, lowered or normal
Term infants are more likely to be febrile
Pre-term infants are more likely to be hypothermic
The clinical presentation can vary from very subtle signs of illness to clear septic shock
Frequently, the symptoms will be related to the source of infection (e.g. pneumonia + respiratory symptoms, meningitis + neurological symptoms)
Investigations for neonatal sepsis?
Blood culture
FBC - abnormal neutrophil count
CRP - help to guide management
Blood gases - metabolic acidosis is particularly concerning for neonatal sepsis, particularly a base deficit of ≥10 mmol/L
Urine MC&S - more useful in LOS, show signs of infection (^ leukocytes, positive culture, haematuria, proteinuria) if urosepsis
Lumbar puncture - if suspecting meningitis as source of infection
Management of neonatal sepsis?
intravenous benzylpenicillin with gentamicin as a first-line regimen for suspected or confirmed neonatal sepsis - unless local bacterial resistance patterns disagree
CRP measured to monitor progress
antibiotics can be ceased at 48 hours in neonates who have CRP of <10 mg/L and a negative blood culture at presentation and at 48 hours
Normally, in neonates with culture-proven sepsis, duration will be approximately 10 days
O2, fluid and elctrolytes
severely ill neonates may need volume and/or vasopressor support
prevention/management of hypoglycaemia
prevention/management of metabolic acidosis
