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Flashcards in Infectious Disease Deck (26)
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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


Dental issues

-aciduric and acidogenic bacteria (strep mutans)
-dietary sugar --> decreased pH --> demineralization of enamel --> cavities



-transmission through respiratory secretions
-viral culture, PCR/DFA testing, CBC with diff
-supportive care, hydration, rest, antipyretics, isolation precautions



-congenital and postnatal presentation
-antiviral therapy and supportive care


Ebstein barr virus

-causative factor in infectious mononucleosis
- watch for splenic rupture and splenomegaly


Common fungal infections

-histoplasmosis, candida species, pneumocystis jiroveci (PCP)
-therapy : fluconazole, voriconazole, amphotericin B complex, bactrim (TMP-SMX) for PCP prophylaxis


Sexually transmitted infections

-gonorrhea --> IM ceftriaxone + azithromycin or doxycycline
-chlamydia (most common STI) --> azithromycin or doxycycline
-syphilis --> penicillin


Lyme disease

-usually presents as eythematous macule with clearing of center
-less than 8yrs --> amoxicillin
-older than 8yrs --> doxycycline
localized disease 14-21d, extend to 21-28d for multi erythematous macules, facial nerve palsy and arthritis


Rocky Mountain spotted fever

-systemic vasculitis, fever and rash that develops of wrist, ankles, palms and soles that spreads to trunk
-untreated at risk for DIC and septic shock
-treatment with doxycycline



-salmonella enterica
-enters through GI tract and spreads to lymphatics, blood, liver and spleen --> leads to widespread bacteremia and endotoxins release
-treatment with ceftriaxone or ciprofloxacin



-mosquito transmitted parasitic infection, parasites travel to liver, erythrocytes become infected and begin symptomatic phase
-presentation: paroxysmal fever, chills, headache, malaise, cough, hemolytic anemia with thrombocytopenia (evidence of cell lysis), proteinuria, hypotension, metabolic acidosis
-diagnosis: thick and thin blood smears to identify parasites every 12-24 hours
-management: IV artersunate or quinidine with doxycycline, tetracycline, or clindamycin



-mosquito transmitted viral infection
-non specific febrile illness with retro orbital headache, myalgia, macopapular rash --> defervescence within 7 days or progresses to severe illness --> vomiting, mucosal bleeding, leukolenia, shock, plasma leakage, pleural effusion, DIC
-diagnosis: leukopenia with thrombocytopenia, ELISA for anti-dengue IgG and IgM antibodies
-supportive care