Infectious Diseases Flashcards
Lab methods-
Wright stain = stool WBCS
Fluorescent antibody antigen stain for HSV1/2, VZV, RSV, adenovirus, flu A and B, paaflu
Direct obs/wet mount for fungal, dark-field for syphillis
PCR
Indrect = intradermal skin test for tb and coccioides
Ab testing for EBV, CMV, VZV, HIV, toxo, bartonella, henselae, myco pneumo
Nonspecifics like CRP and ESR
High risk groups for fever
Infants under 28 days, older infants w/ high fevers > 39C/102.2 who appear ill, immuno def, sickle cell, hronic disease
Eval of fever in infant <3 months
3-10% well appearing and 17% toxic have serious bacterial infec
Why? Transplac, passage through bc, postnatally. Viruses most common
Clin fx= nonspecific, fever, dim app, irritable, cough, rhino, v/d, apnea
Dx- clinical/lab fx- det low vs. high risk (abx recently? focal infection?) do cbc, blood culture, UA/UC, CXR if resp distres, and CSF. Low risk if wbc between 5-15K, bands <5Wbc on stool wright, normal csf.
Fever hospitalization for:
all infants <=28 days
Infants 29-3 mo with toxic look, meningitis suspicison, PNA, pyelo, bone/soft tissue infection
Uncertain oupt f/u
Abx for fever based on
Infants <28 need IV abx until cultures are negative
Infants 29-3 mo w/ low clin/lab criteri + outpt can get oupt parenteral
High risk older infants need hospitalized parenteral
Abx in fever specifics
0-1 mo? GBS, E. coli, List- amp + gent or cefotax
1-3 mo? GBS, Strep pneumo, LM- amp + cef (+ vanco if worried abt bact meningitis)
3 mo- 3 y? Strep pneumo, H flu, neiss men- cef (+ vacno if bact mening)
3- adult? strep pneumo + NM- cef (+ vanco if bact mening)
Fever eval, 3-36 mo
Risk bact 3-10%, likelhood bacterimia up w/ up fever/peripheral WBC
Strep pneumo most common
If kid toxic, do complete sepsis eval + iv abx + hospital
Nontoxic and < 2 years, do blood culture all kids or if wbc> 15k, stool culture if blood/mucus/wright stain, CXR if resp issue, empiric abx if WBC> 15k OR all kids. Reeval in24-48 hrs
FUO
Fever > 8 days to 3 weeks, with no dx
Usually common illness w/ weird presentation, big ddx
25% resolve spont
Eval- comprehensive hx, ROS, PMH, SH, detailed p/e, CBC w/ diff, ESR, CRP, serum transam (hepatitis), UA/UC, blood cultures (endocarditis), Anti-strep O titer (rheum fever), ANA, RF, stool culture, TB, HIV, lots of imaging
MGMT- hospitalize for eval
Bacterial meningitis
Most in first mo. of life, risk if young, immunodef, or anatomic defect (skull frac, vp shunt)
Fx- babies? nonspecific sx, minimal fever, maybe bulging font, older kids?fever, change consciousness, nuchal rigid, kernig/brudzinski(hip/neck), seizure, photophob, emesis, h/a
Dx- high IoS, all kids get LP- pleocytosis w/ neutros, WBC>5K!, low glucos, CSF:serum 3 mo- 3rd gen cephal, + vanco. give corticostreoids w/ or before first abx to down hearing loss
Supportive care- IVF, look at uo, serum sodium
Bact meningitis complications
Gram negs have most complications, then S. pneumo, HIB, and Neisseria (5-50% mort dep on bacteria)
Hearing loss is most common, up to 25% pts
Global brain injury 5-10%
SIADH, seizures, hydroceph, brain abscess, cranial nerve palsy, learning disabled, focal neuro deficits
Aseptic Meningits
Inflamm w/ CSF lymphocytic pleo, if viral- normal CSF glucose, min elevated CSF protein
Clin fx- mild w/ fever, h/a, emesis or severe
Aseptic TB nonspecific lethargy, 2nd week => cranial nerve deficits, altered LOC, paraplegia, eventual death
Dx- viral mening CSF culture, or PCR for EBV, CMV, HSV, enterovirus, + surface enterovirus in throat/rectum suggestive, can do RPR, India ink for crypto, serum ab for coccidio myco, Lyme disease/cysticerosis
TB meningitis
Lymphocytic pleocytosis, low glucose, super high protein, basilar enhancement
Postive acid fast csf stain, or + PCR
50% neg chest XR, tuberculin skin test
Simple URI
Etio = rhino, paraflu, coronavirus, respiratory syncytial virus
Clin fx- low grade fever, rhino, cough, sore throat, 7-10 days
Color of nasal discharge does NOT predict sinusitis
Persistent sx or fever prompt for bacterial superinfection
Dx on fx
Mgmt - YDRATION, exclude more serious things, otc, NO ABX
Sinusitis
Ethmoid/max sinuses in 3-4 mo gestation, sphenoid sinus 3-5 yo, frontal 7-10
Acute, sub acute, chronic
Dx on clin fx, imaging NOT USEFUl
Acute sinusitis
Acute persistent = nasal d/c and cough 10-30 days, h/a bad breath, facial pain, low fever
Etio = s.pneumo, h flu, m. catarrhalis
Mgmt- amoxicillin, amox-clavulanate (augmentin), 2nd gen cephalo 10-14 days
Acte severe- high fever, purulent 2-5 days, same etio, same mgmt
Subacute sinustis
Same features, but 30-90 days
etio = same- s.p neumo, h flu, m cat
Mgmt = same
Chronic sinusitis
> 90 days!
Etio = maybe underlying CF, allergy, immunodef, s. aureus, anaerobes
Mgmt = trial broad spec abx, ct scan sinuses, iv abx
Pharyngitis
Etio = coxsackie, EBV, CMV + same as URI
Bacterial = strep pyogenes (GABHS = strep throat), aracnobact hemoyticum, and diphteria
Clin fx= viral + strep overlap, hard to tell
dx- strep test (antigen test = rapid), 5% has pharynx GABHS
MGMT- viral = supportive, hidration. GABHS = oral penicillin VK (single IM does benza), if allergic oral erythromycin/macrolides
EBV pharyngitis- maybe steroids
Diphteria = oral erythromycin/parenteral penicillin
EBV pharyngitis
enlarged posterior cervical LN, malaise, hepatosplenomeg
Coxsackie pharyng
Painful vesicles/ulcers on post pharynx and herpangina (soft palate), or hand-foot =-mouth
Strep throat
GABHS in 5-15 y/o winter/spring, Lack of other URI exudate on tonsil, petachiae on soft palate, strawberry tongue, enlarged tender anterior lymph nodes Fever Scarlatiniform rash
Diptheria
RARE, gray adherent tonsillar membrane
toxin-med cardiac/neuro compx
Acute OM
Acute infec of middle ear
OME = w/ effusion, w/out sx of infection
Etio = s.pneumo, non type h flu, m. cat, URI AOM share bacteria
Clin fx- usually after/during URI, fever, ear pain, less hearing, sx less reliable in lil kids, if tymp membrane perfs, pus/fluid form ear
Dx = identify fluid within middle ear space! neumatic otoscope- fin abnormal mvt of eardrum! Or erythema/loss of tymp membrane landmarks, less reliable. can do tympanocyntesis/perf tymp membrane w/ pus within external aud canal
MGMT- abx for AOM, but controversial b/c will resolve on own. If use, do Amoxicillin- but if in day care or infected in past 1-2 months, then MRSA more likely, so do high dose amox, augmentin or cephalo. Macrolides in penicillin allergy
NO abx for AME
Otitis externa
Infection of external auditory canal
Pathog- things that mess up barrier- trauma, cerumen removal, maceration of swin from swimming, moisture
Etio- pseudomonas, staph auerus, candida albicans, or AOM w/ perfed ear drum
Clin fx- pain, itching, draining from ear. Systemic sx absent, hx consistent w/ AOM helps decide if perf
Dx- erythema/edema of EAC, white/purulent material within canal, tenderness on palpation/mvmt of tragus, visualize tymp memb to exclude perf, maybe culture
Mgmt- restore EAC to natural acidic environemtn. Acetic acid in ear if milkd, more severe do topical abx + corticosteroic. Perfed AOM w/ OE- oral/topical abx
Cervical Lymphadenitis
Enlarged, inflamed, tender LN
Etio- local bact infection (s. aureus most common, s. pyogen too, mycobact (tb/avium), b/ henselae (cat scratch).
Reactive lymphatd in responsive to infections in larynx/teeth/head/neck soft tissue
Virus EBV, CMV, HIV also
Kawasaki = UNILATERAL cervical lymphad, t. gondii can look like mono
Structural lesions in neck (brach cc or cyst hygroma) 2ndary infec
Fx- mobile, tender, warm LN, single or multiple, maybe systemic
Dx- tests like tb skin, CBC w/ diff, ab titers for b. hensela/gondii if unresponsive, ab titers for EBV/CMB/HIV if diffuse/persistent. Imaging for cervical anatomy/abscess
MGMT= empiric abx to staph/streph (cephalo 1 gen, or anti-staph penicillin 7-10 days, IV if toxic)
Parotitis
Inflamm of parotid salivary glands
Etio- mumps/other viruses = bilateral involvedment (CMB, EBV, HIV)
Bact parotitis = s. auerues, s. pyog, m tb, unilateral!! uncommon unless down salivary flow/stones
Clin fx- swelling above angle of jaw, oropharynx with pus from Stensen’s duct (parotid duct)
Dx= culture drainage, viral w/ serology, mumps in urine
Mgmt = virus w/ supportive, acute bacterial = abx to staph/strep, maybe i&d
Compx- mumps => meningoenceph, orchitis/epididmytis/pancreatitis
Acute sup parotitis => abscess + osteomyelitis of jaw
Impetigo
Superficial skin infection, upper dermis
Staph aureus most common, GABHS also
Fx- honey-colored crust/bullous lesions, commonly on face, esp nares, easy spread
Visual dx, no culture, give topical mupirocin or oral abx (dicloxacillin, cephalexin, clinda)
Compx bacteremia, post strep glomneph, and staph scalded skin
Erysipelas
Dermal lymphatics, usually GABHS
Clin fx = tender erythematous skin + distinct border, face and scalp
Visual dx, give systemic GABHS theraphy
Compx = bacteremia, post strep glomneph, nec fasc
Cellulitis
Skin infection within dermis
GABHS, s. aureus, break in skin barrier
Cin fx- warm, red, tender, indistinct border
Dx visual inspection, rarely postive blood culture, if agressive, biopsy/culture leading edge
Mgmt = oral/IV abx w/ cephalo first gen or anti-staph penicillins