Infectious Disease Flashcards
Meningitis Etiologies
Bacterial
Viral
Fungal
Noninfectious
Community-acquired
Healthcare-associated
Bacterial: Strep pneumo, N. meningitis, H. flu
Viral: Enterovirus, HSV, HIV, West Nile, VZV, mumps
Fungal: Cryptococcus MC
Noninfectious: tumor, trauma, brain abscess, subdural empyema, pharmacologic reaction
Community-acquired: S. pneumo, N. meningitides, H. flu, Listeria
Healthcare-associated: Staph and aerobic gram-negative bacilli
Meningitis Symptoms
Abrupt onset, intense HA
Classic triad: Fever, nuchal rigidity, AMS
Photophobia, lethargy, N/V, joint pain
Petechial rash (non-blanching) associated with N. meningitidis
Seizures - bad sign, be concerned for encephalitis too
CNS Infections in Elderly - Red Flags
Often lack fever; often present with delirium w/ any infection
Behavioral/personality changes
Seizures
Lack of source for other infections
HA, nuchal rigidity, exposure to infected
Low threshold to do LP
Head CT with LP
Immunocompromised
Hx seizure w/in 1 week presentation
Neurologic abnormalities: abnormal LOC, CNS disease, papilledema, focal neuro deficit
Mandatory in all patient with possible focal infection
With meningitis, w/o papilledema or focal neuro sx do the LP immediately
Meningitis Workup and Treatment
Treatment: 2g IV q12h Rocephin immediately after LP, admit
Workup: Blood cultures, CBC, Chem 7, CSF
Encephalitis
Inflammation of the brain
MC viral - HSV 1&2 - rapidly progress and life-threatening
- also west nile, CMV, mumps, EBV
Have to have altered neurologic findings to call it encephalitis
-personality change, paralysis, hallucination, altered smell, speech issues
Pediatrics and Meningitis
Bacterial MC between 2 months-2 years
Irritability and poor feeding may be only signs in young infants
Paradoxical irritability - crying worsens when held - suggests meningitis
Meningitis Etiology in Peds
Strep penumo
Neisseria meningitidis
H. influenzae type B - rare now w/ vaccine
Neonates: think group B strep
Encephalitis symptoms
Minor: may just have flu-like symptoms
Severe: Ha, AMS, confusion, fever, agitation, neuro changes
Severe in kids: bulging fontanels, N/V, body stiffness, paradoxical crying, poor feeding, inconsolable
Workup and Treatment of Encephalitis
CT/MRI
CBC, CMP
LP - PCR for HSV1, serology
-rbcs in nontraumatic CSF tap are HSV until proven otherwise
Treat: Acyclovir 10 mg/kg IV q8h - empiric HSV treatment
Septic Arthritis
Medical emergency - destroy joint in 12-24 hours; asymmetric
Acute/subacute pain, erythema, swelling, limited joint motion, systemic sx
Joint tap shows >40,000 wbc - r/o gonorrhea
Gram stain unless gonorrhea - wont show up
-get cervical, urethral, rectal GC culture if suspected
Tx: high-dose IV antibiotics
Bacteremia
Fever, chils, rigors, disorientation, hypotension, respiratory failure
Source of infection from respiratory, central venous catheters, UTI, GI tract, biliary tract, skin, soft tissues
Gram Negative Bacteremia
25-50% all blood stream infections
More sick than gram +
Treatment for severe: gentamicin/tobramycin/amikacin + cefepime (antipseudomonal cephalosporin)
Consider vanco until culture come back
Gram Positive Bacteremia
Staphylococcus aureus is leading cause
Empiric treatment: vancomycin
- MSSA - PCN, nafcillin/oxacillin, vanco
- MRSA - vancomycin or daptomycin
r/o infective endocarditis with transesophageal echo
IVDA makes you more concerned for staph
Sepsis
Infection + other general symptoms (fever, HOTN, tachypnea, AMS, edema, hyperglycemia w/o DM (>140))
Have HOTN with wide pulse pressure
Poor urine output, elevated creatinine INR and PTT, low platelets
Ileus, elevated bilirubin, elevated lactate, decrease cap refill
Treat: supportive and empiric abx
Cellulitis
Emergent if: around face/hand, cellulitis w/ DM or PVD, or local infection with leukemia or HIV
Cellulitis: affects skin through dermis
All cellulitis/folliculitis/furunculosis is MRSA until proven otherwise - bactrim DOC, Clinda 2nd line
Impetigo
Superficial skin infection MC in kids
Commonly due to strep, maybe staph
Treat with bactrim
Endocarditis - high risk
IVDA
Previous valve surgery/abnormal valve (regurgitant)
Poor dental health - source
Present with night sweats, anorexia, weight loss
Also present with cardiac failure, stroke (septic emboli), cold extremity from emboli
Endocarditis - Valve MC affected with IVDA
Tricuspid valve
Often present with bilateral embolic pneumonia
Often lack the right-sided murmur
Endocarditis Characteristics
Cutaneous lesion: conjunctival and palatal petechia, splinter hemorrhages, Osler (finger/toes) and Janeway (palms/soles) lesions
Roth spots (pale ovals w/ hemorrhage around) on dilated eye exam near optic disk
May have normocytic, normochromic anemia
Get trans-esophageal echocardiogram to see valvular vegetation
Toxic Shock Syndrome
Absorption of toxin from localized staph aureus infection
Short prodrome: fever, myalgias, V/D, pharyngitis
Rapidly develops fulminate shock and fever w/ multiple organ failure
Diffuse blanching macular erythema w/ pan-mucosal inflammation - fades in 2-3 days
Desquamation of hands and feet 5-12 days after rash disappears
Hallmark Labs for TSS
Negative blood cultures
Elevated CPK
Sterile pyuria
Rocky Mountain Spotted Fever
Rickettsia Rickettsi
Fever, chills, malaise, myalgias, frontal HA
Pink macular rash on palms/soles, wrists and ankles on 5th day - becomes petechial, purpuric, and spreads over 24-48 hours
Lyme Disease
Borrelia burgdorferi
Erythema migrans - rash w/ central clearing = target lesion
Fatigue, lethargy persists for months/years
Arthritis, neuropathy for years after
