Infectious Disease Flashcards
Fever in the neonate
- neonates at greatest risk for significant bacterial infection
- have maternal IgG cells but without immunologic memory and adaptive immunity, B and T cells in normal quantity but less efficient
Neonatal sepsis
- infant <28d: rectal temp >38 or hypothermia, lethargy, poor feeding, resp distress, irritability, jaundice
- normal WBC count does not exclude infection
- if RSV or UTI+ still at risk for SBI and needs evaluation
- group B strep, listeria monocytenes, E. coli, enterococcus, staph aureus, HSV, CMV, VZV, RSV, candida
- **gentamicin and ampicillin OR ampicillin and cefotaxime at meningitis dosing +/- acyclovir **
* *ampicillin: listeria
* *gentamicin: gram - coverage
* *cefotaxime: no pseudomonas coverage
Fever without a source
- presence of fever without localizing signs on PE
- most will have underlying self limiting viral infection
- dramatic decrease in h flu and step pneumoniae d/t vaccines
- teething not likely to cause fever >38.5
Fever of unknown origin
- fever >38.3 for at least 8 days and up to 3 weeks without clinical diagnosis –> commonly infectious disease and connective tissue disease
- always check travel history
Common infectious disease diagnostic testing
- C reactive protein: non specific inflammatory marker
- Erythcyte sedimentation rate: nonspecific, detects acute or chronic infections, inflammation, neoplasms, tissue necrosis –> trending more valuable than one value
- Polymerase chain reaction: virology detection
Fever and neutropenia
-fever with neutropenia in oncology patient –> single temp > 38.3 or fever for over 1 hour with ANC <500 or expected to decrease to <500 in the next 48 hours
ANC = WBC x total neutrophils (seg neutrophils % + seg bands %) x 100
Normal ANC > 1000
- gram positive bacteremia most common (coag neg staph, strep viridians, staph aureus and MRSA)
- diarrhea most commonly from c diff and salmonella
- gram neg bacilli: E. coli, pseudomonas, enterobact
- fungi: opportunistic (aspergillus, cryptococcus, pneumocystis jiroveci
- viral: herpes simplex, varicella zoster
Fever and neutropenia management
- low risk : floroquinolone +/- amoxicillin clavulante
- high risk : antipseudomonal penicillin, cephalosporin, carbapenam
do not add therapy due to fever alone in stable patient
- vancomycin or linezolid for cellulitis or pna
- aminoglucoside and carbapenam for pna or grm neg bacteremia
- flagyl for c diff
-antifungal therapy only for neutropenic patients with fever for 4-7 days after starting ABX
Systemic inflammatory response syndrome
-SIRS : non specific inflammatory process
-sepsis : SIRS with a known or suspected infection
- toxins released in gram + infection initiates cytokine cascade resulting in fever, vasodilation and hemodynamic instability
Two or more - temp >38 or <36, tachycardia or bradycardia in children less than 1 yr old, tachypnea or mechanical ventilation, leukocyte count elevated or depressed
- severe sepsis : sepsis plus cardiovascular organ dysfunction, ARDS, other organ dysfunction
- septic shock : sepsis plus cardiovascular dysfunction or refractory hypotension
septic shock presentation - subnormal temp, irritability/lethargy, tachypnea with respect distress, tachycardia/poor perfusion/ hypotension, shock (warm - vasodilated or cold - vasoconstricted), multiple organ dysfunction
septic shock management - fluid restriction to goal CVP 10-12***, inotropic support, septic work up, broad spectrum antimicrobials
Disseminated intravascular coagulation
- alteration in clotting triggered by tissue injury, bleeding is initial symptom, thrombosis with tissue ischemia, d diner is diagnostic***
- manage shock and address coagulation : vitamin k, cyproprecipitate, FFP (transfusing both pro and anti cogulants is helpful), platelets
Meningococcal infections
- acute bacterial illness, neisseria meningitidis grm neg encapsulated organism with 50-100x endotoxins load of other gram neg bacteria
- rapid onset of symptoms : fever, altered mental status, poor perfusion, tachycardia, hypotension, tachypnea, irritability, purpura
- labs : CBC with diff, complete sepsis work up, liver enzymes, renal function, LP
- management** : droplet isolation, ABCs, fluids, blood products, ventilation, 3rd generation cephalosporin abx (ceftraixone or cefotaxime)
- close contacts need prophylaxis with 1 dose of cipro or rocephin IM
Common drug resistant organisms
- CA-MRSA : community acquire mrsa, resistant to beta lactams, treat with clindamycin, vancomycin, septra, linezolid
- DRSP : drug resistant strep pneumo, resistant beta lactams, treat with clinda, vancomycin, high dose beta lactams
Meningitis (general)
- infection of the meninges, cerebral vasogenic/cytotoxic/interstitial edema ensues
- meningeal signs : kernig and brudzinski
- lumbar puncture with elevated opening pressure (if concern for increased ICP obtain head CT first) –> ratio of RBCs to WBCs should be same as serum ratio, if significant RBCs consider heroes simplex virus
Viral meningitis
- enterococcus most common
- hallmark triad in older children without nuchal rigidity : fever, headache, altered LOC
- CSF results : WBCs <500, elevated protein, normal to low glucose, negative gram stain
Bacterial meningitis
CSF results : >1000 WBCs with predominant leukocyte, elevated protein, low glucose, positive gram stain, cloudy to purple to color
- neonate : group b streptococcus, E. coli, listeria monocytogenes
Fever, lethargy, bulging fontanel, poor feeding, jaundice, decreased muscle tone
**ampicillin and gentamicin or cefotaxime with acyclovir - young children (2-23months) : streptococcus pneumoniae, n meningitides, group b strep, h flu
Fever, headache, nuchal rigidity, kernig and brudzinski, poor feeding, decreased muscle tone
**vanomycin and ceftriaxone with acyclovir - > 2 years : n. meningitides, s. pneumoniae, h flu
Altered mental status, hypertension, bradycardia, petechiae
**vancomycin and ceftraixone
Toxic shock syndrome
-multi system febrile illness caused by strep pyogenes and staph aureus –> massive activation of host cellular immune response –> begins with non specific symptoms progresses to fever, hypotension and organ dysfunction
Fever >39, diffuse macular rash, desquamation of palms and soles, hypotension, multi system involvement, negative blood, threat and CSF cultures, no elevation in serum titers for RMSF, leptospirosis or measles
**fluid resuscitation, abx (vancomycin + ceftraixone, add clindamycin if high suspicion for tss), ivig
