What is common with the relationship between the host and the organism
Some organisms almost always symbiotic / commensal (Lactobacillus)
Some organisms are always pathogenic (e.g., Shigella, Bacillus anthracis)
In humans, most organisms are neither (e.g., Flavimonas orizahabitans)
Some can be either, given the right circumstances
e.g., Enterococcus, E coli, Streptococcus agalactiae, etc.
What determines disease?
The interaction between host and bug determines disease.
Does the same bug cause the same effects in all patient?
No, The same bug in different patients might have different outcomes.
Will antibiotics cure a disease if a patient has a poor immune system?
No, A functioning immune system is better than all antibiotics. Antibiotics just assist the body in fighting disease. Antibiotics won’t work if there is no immune system. If you have a compromised immune system, antibiotics may not be able to get the job done.
What is important to remember when deciding on medical interventions?
Medical interventions can increase risk of infection. Need to think about the risks versus benefits. All interventions are a balance between risk and benefit.
What is very important in infectious diseases?
Exposure is everything in infectious disease
Why are the risks of term Neonates?
Higher risk for infection
naïve immune system- lack of memory B & T cells & neutrophils with poor function
complement levels low
IgG obtained from mother but the specificity may not be against the bugs that they are exposed to
What is extremely important in trying to clear infection?
Complement system, intact skin and mucosal barriers
What are the risks of Preterm Neonates?
Even higher risk for infection
complement levels lower than in term infants
less IgG transferred from mother
in extremely premature infants skin is immature
What does prolonged ROM cause?
Opens fetus up to infection because they no longer have protection
How does congenital infections affect the fetus
Congenital infections can cause defects
Some infections can be immunosuppressive
If the have one STD they may have another ( remember to consider this)
What is puerperal fever?
Fever from Group strep A infection – this is an extremely fast bacteria-can die within hours
Not often seen in US
From unclean practices
NEVER blow off maternal fever – in group A- mother gets fever after birth and is dead within 4 hours
Where does GBS colonize?
In genital track and rectum
What special problems exist in the Neonatal population?
Twins / multiples
Prolonged rupture of membranes
Maternal flora (e.g., GBS)
Birth environment not ideal (toilet delivery, en route delivery, home delivery)
What Problems do hospitalized neonates face?
most of the time the infant is premature thus has a longer stay
prolonged antibiotic exposure
violation of natural barriers (ET tubes, IVs, UAC/UVC, etc.)
Is an infant who has better PNC and from a better “environment” less likely to get infected by a congenital infection
Infants can have the same bug even though they come from different environments – don’t think that just because an infant has excellent PNC that they won’t have a nasty bug
What are the causes of non infectious diseases in the sick neonate?
What are the treatment methods for S aureus in line infection
pull the line. Period - delay associated with dissemination
What are Fungi
found in soil,
some normal bowel flora
You have a 26 wk preterm infant critically ill w/ GNR (presumed meningitis)
3 wks cefotaxime + gentamicin good early response, then near the end of therapy
As + Bs, “not acting right” WBC 7,000; no shift Plt 35,000 *****What do you think
Clues: platelets abnormal, long term antibiotics
When does the isk of fungal infection increases with more antibacterials
What is the most common fungal pathogen in NICU
C parapsilosis > C albicans
How does candida cause an infection?
attaches to epithelia, pseudohyphae penetrate buds, can spread via blood
forms abscesses / mycetomas in kidney, spleen, liver, brain, bone, endocarditis
What are the risk factors for Candida
extremely low birth weight
broad-spectrum antibiotics- 3rd gen cephalosporins
IV catheters / prolonged ETT
prolonged TPN / lipids – the yeast loves the high sugar content
What are the clinical features of Candida—
pustular rash (congenital)
thrush / diaper dermatitis /skin-fold infections
systemic disease similar to bacterial sepsis
What are Strategies for diagnosis of Candida
difficult to diagnose
20-60% BCx positive
lesion / abscess culture helpful
fungal blood cultures for some
Sick kid plus low platelet count – think of this
How do radiographs help with fungal dx
abdominal ultrasound (kidney, liver, spleen)head ultrasound / CT / MRIplain films / bone scanMay see fungal balls
What are the Strategies for work-ups for fungal infections
if cultures positive, you should- radiology, LP with cultures, fundoscopic exam – fungal balls, echocardiogram – fungal balls
If the cultures are negative you may consider these things
What are the Strategies for treatment of fungal infections (Candida)
amphotericin B is drug of choice
liposomal amphotericin B with renal impairment(not renal disease)
fluconazole in renal disease
What Strategies for treatment of a candida line infection
remove lines. Period. – unless they will die without the line
What is the problem with Line removal
Pediatric ID always says pull the line
Neonatology gotta keep the line
find a compromise position
What are basic rules about pulling the line
Always pull. Period.
• S aureus
• Multiple positives
Maybe can keep line. Maybe.
• CoNS, some GNR
What is the Classic presentation of neonatal herpes?
vesicles on the presenting part – but this isn’t always truefrequently do not see vesicles
38 wk term infant, AGA, excellent prenatal care, breech delivery, at 48 hrs, fever
WBC 7,000; no shift, rash noted What are the clues here
Rash at 48 hours and fever
This is herpes
What are the Three primary syndromes of herpes
Mucocutaneous – peaks at 1 week
Disseminated – peaks at 2 weeks
neonatal encephalitis- peaks at 3 weeks
When does the presentation of the classic forms of herpes decrease
Neoantal herpes in the classic forms pluments at 4 weeks
What is the problem with mucocutaneous & disseminated
often have CNS findings
What clinical test should be completed for Neonatal Herpes
LP (HSV culture and PCR)- very important to send the PCR
culture of vesicles (and DFA) – unroof the vesicle and get the cells from the base – this is where the virus is
surface culture - (eye, ear, mouth, axilla, anus)
LFTs – almost always associated with hepatitis
cervical culture of mother – almost all primary infections are cervicitis
What used to be the dx test to confirm Neonatal Herpes
Once upon a time diagnostic test of choice for encephalitis wasbrain biopsy! And Growth usually within 5 days
But PCR is now in house at DUMC BUT sensitivity not 100%
What is the incidence of Neonatal Herpes
Est. 1 in 3000 to 1 in 20,000 births
NC 2001 → 118,185 births
6 to 40 cases across entire state
What are the Strategies for treatment of neonatal herpes
acyclovir 20 mg/kg iv q8h x 21d
we follow these kids in ID clinic keep them on ACV for 1-2 years
Studies show that there is a decreased chance of herpes encephalitis with prolonged treatment
What is Herpes Encephalitis
Very severe disease
mortality estimates 25-75% (even with therapy)
patients are sick! - not better after 1-2 days
Prefers the temporal lobes
usually findings on MRI / CT
WHAT IS a fever without source (FWS)
fever of recent onset
no adequate explanation based and on history and physical exam
fever without source (FWS) ≡ fever without localizing signs
What is a fever of unknown origin (FUO) in pediatrics
fever of >7 days duration
no diagnosis after initial work-up
What are the characteristics of fever without source (FWS)
fever of recent onset (<1 week)no adequate explanation based on history and physical exam(should be careful H+P)5-10% (22%) of children with fever lack localizing signspeak incidence in 2nd year of lifeestimated a practicing pediatrician sees this once every 4-5 days
Compare FWS andFUO
Differential diagnoses are different
FWS needs more immediate evaluation
FUO – Can take a more thoughtful approach
What are the symptoms of FWS
some are presenting with a new chronic illness
some are gravely ill
most are not
the evaluation is a bit like panning for gold…you must always pay attention!
How is FUO different than FWS?
you are out of the acute stage
you have already done a work-up
What are the two approaches to further work-up of FUO
test for everything at once
test in a stepwise fashion – this is preferred
What is the FUO—Epidemiology
Different as compared to adults ( inadults FUO is cancer until proven otherwise)
most have uncommon presentations of common illnesses
case series—only 5 of 418 had rare disorder
most series state that 10-20% of cases never get a diagnosis (50%) – important to tell the family this
Tell them that - unlike adults, most children get better
Who works together to dx FUO
in cases of FUO, three services are routinely consulted
You are in the ED on Wednesday, near the end of your shift. You are asked to eyeball an 11 mo male with decreased feeding and urination, fever and lethargy, all with sudden onset. On exam you see a rash on with small, non-blanching, red macules with dark centers
Your next action for this patient should beA. diagnose a viral illness and dischargeB. obtain a blood cultureC. perform a lumbar punctureD. administer ceftriaxone IM.
This is menigecococcal – this is a characteristic rash – So answer is BCD
A child is dx with meningitis Children in his daycare room should
A. receive routine careB. receive vaccination against pneumococcusC. receive rifampin prophylaxisD. have lumbar punctures performed.
Answers C- receive rifampin- anyone with close contact
On Thursday, you see a 6yo ♀ with 3 days of fever & sore throat. Her mother reports a red, raised rash. You find HR 120, T 39. Her L leg below the knee is swollen. She is crying and inconsolable.
Your next action for this patient should beA. LA Bicillin for strep throatB. start oral penicillinC. start IV penicillin and clindamycinD. call for a surgical consult.
This is necrotizing faciitis – choose C & D, the clues are red rash and leg swollen – this is a surgical emergency
On Friday, you see a 20mo ♀ with a 2 day history of fever & fussiness. Her mother notes the child is refusing to walk and is fussy with diaper changes. You see a child with T 38.5 and holding her R leg flexed and externally rotated.
Your next action for this patient should beA. call for an orthopedic consultB. call radiology for a hip ultrasoundC. start meropenemD. diagnose toxic synovitis and discharge on NSAIDs.
This is septic arthritis of the hip – choose A & B
The clues are the flexed externally rotated hip
On Sunday, you see a 5yo ♂ with 3-4 days of congestion / rhinorrhea. This morning his mother noted the acute onset of R eye swelling. On exam you see tense edema of the eyelid with proptosis, lateral gaze paralysis, conjunctival injection.
Your next action for this patient should beA. IVIG infusionB. Call ENT / OphthoC. start 3rd generation cephalosporinD. thyroid studies.
This is orbital cellulitis – the clue is proptosis choose B & C
On Monday, you see a 2yo ♂ whose family are recovering from a “flu-like” illness. He had been recovering until this morning when he developed a distressed look and high fever. On exam he has inspiratory stridor, retractions, and a normal O2 saturation.
Your next action for this patient should beA. Immediate intubationB. CXRC. Chest CTD. administer nebulized albuterol.
Choose B based on respiratory symptoms
On Monday, you see a 2yo ♂ whose family are recovering from a “flu-like” illness. He had been recovering until this morning when he developed a distressed look and high fever. On exam he has inspiratory stridor, retractions, and a normal O2 saturation. The CXR is shows no foreign body, little parenchymal disease.
A. Immediate intubationB. start vancomycinC. Chest CTD. administer nebulized albuterol.
This is bacterial trachitis – flu like symtoms is a clue b/c this is a side effect of the flu; choose A & B
In 1985, you see a 3yo ♀ who had mild fever and cough followed by the sudden onset of respiratory distress and irritability. She is hoarse, sitting in mother’s lap, leaning forward, drooling, and has retractions.
Your next action for this patient should beA. Immediate intubation by the internB. CXRC. immediate intubation by an anesthesiologistD. start an IV for antibiotics.