Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Medicine Refresher > Infectious Disease > Flashcards

Infectious Disease Flashcards

1
Q

Osteomyelitis gen info

A

Bone infection –> inflammatory destruction of bone
Two categories:
- hematogenous, secondary to sepsis
- direct spread of bacteria
> adjacent infection (infected diabetic foot ulcer, decubitus ulcer)
> trauma (open fx)
> vascular insufficiency (PVD)
MC microorganisms: s. aureus, coagulase-neg staphylococci
Can involve any bone, commonly; long bones, foot/ankle, vertebral bodies

OM of vertebral body d/t TB –> pott disease
chronic OM –> bone necrosis + soft tissues compromise or relapse of previous OM, vey challenging to tx, almost impossible to completely eradicate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Osteomyelitis risk factors (complications or chronic)

A

open fx
DM
IVDU
sepsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Osteomyelitis clinical features

A

pain over involved area of bone mc
localized erythema, warmth, swelling
systemic sxs; fever, headache, fatigue
draining sinus tract thru skin in chronic disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Osteomyelitis diagnosis

A

WBC count
ESR, CRP (monitoring response to therapy)
Needle aspiration or bone biopsy (OR) - most direct/accurate diagnostics (+culture)
plain radiograph - early changes like periosteal thickening or elevation show up after 10 days, lytic lesions = advanced dz
MRI - most effective + assess extent of disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Osteomyelitis treatment

A

IV abx 4-6 weeks

  • start only after microbial etiology is narrowed based on cultures or if HDU
  • empiric therapy; abx w high bone penetration like cephalosporins (cefazolin, ceftriaxone, cefuroxime), FQs (levofloxacin, ciprofloxacin, moxifloxacin), vancomycin, linezolid, daptomycin, clindamycin (+- rifampin adjunct for biofilm penetration)
  • add aminoglycoside +- beta lactam if possibility of gram neg infection
  • surgical debridement of infected necrotic bone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Septic Arthritis gen info

A

microorganisms (usu bacteria) invade joint space (not bone itself) & release endotoxins–> trigger cytokine release and neutrophil infiltration –> inflamm response leads to erosion + destruction of joint
Pathogenesis: microorganisms penetrate joint space by;
- hematogenous spread mc
- contiguous spread from another locus of infxn (OM, abscess, cellulitis)
- traumatic injury to joint
- iatrogenic (arthrocentesis, arthroscopy)
Microbio
- bacteria mc; s. aureus mc, strep, n. gonorrhoeae, consider gram neg like pseudomonas, salmonella if hx of sickle cell disease, immunodeficiency, or IVDU
Risk factors
- prior joint damage (RA)
- joint prothesis
- DM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Septic Arthritis clinical features

A

Swollen, warm, PAINFUL joint (painless rom of involved joint –> septic arthritis very unlikely even w erythema. Any micromotion causes severe pain usu)
- ROM active/passive very limited
+- effusion
fever, chills, malaise
MC joint = knee
immunosuppression or connective tissue dz +- polyarticular arthritis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

gonococcal arthritis

A

acute mono or oligoarthritis progressing within days in a migratory or additive pattern; knees, wrists, hands, ankles mc
tenosynovitis in hands/feet
fever, chills, rash (macules, papules, +- pustules) = disseminated gonococcal infection - admit
Aspirate joint, abx + doxy (chlamydia)
consider HIV, syphilis testing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Septic Arthritis diagnosis

A

joint aspiration + analysis of synovial fluid in everyone suss of septic joint:
- wbc with diff; >50,000 wbcs >80% PMNs
- gram stain
- culture aerobic + anaerobic
- crystal analysis; acute gout is mimicker
- PCR synovial fluid; if high suss but above neg
blood cultures
elevated ESR/CRP, leukocytosis
xrays - not very useful unless severe
CT/MRI if sacroiliac or facet joints involved
appropriate mucosal surface cultures (GU)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Septic Arthritis treatment

A

prompt abx tx
- don’t delay in starting if suss
- treat empirically until culture results come back
healthy w s.aureus –> parenteral oxacillin or first gen ceph x 4 wks
- treat w vanc if mrsa suss
Immunocomp –> parenteral, broad-spectrum w gram neg coverage; third gen ceph, aminoglycoside 3-4 wks
drainage
- daily aspiration as long as effusion persists
- vs surgical drainage recommended

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

HIV related illnesses

A 
Opportunistic infections:
Pneumocystis pneumonia
Tuberculosis
Toxoplasmosis
Disseminated MAC
Bartonella spp,
Candida spp, Coccidioides spp (coccidioidomycosis) Cryptococcus spp, Cystosporidium, cytomegalovirus, varicella-zoster virus, and Histoplasma capsulatum.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Lyme Disease general info

A

3 major endemic areas in US:
NE seaboard (maine to MD)
Midwest (north central states like Minnesota, Wisconsin)
West Coast (northern California)
incubation period = 3-32 days
Transmission cycle:
Arthropod-borne disease d/t borrelia burgdorferi (gram negative spirochete) spread by deer tick mc in spring/summer. Transmission more likely if tick engorged or attached >72 hrs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Lyme Disease sxs

A

Stage 1: early, localized infection
- erythema migrans with central clearing (bull’s eye target) around bite within a month of bite +- viral-like syndrome.
- large, painless, well-demarcated commonly on thigh, groin, or axilla
- multiple lesions = hematogenous spread (below)
Stage 2: early, disseminated 1-12 wks
Infection spreads via lymphatics/bloodstream within days to weeks after erythema migrans
sxs: intermittent flu-like sx; headaches, neck stiffness, fever/chills, fatigue, malaise, msk pain
After several weeks, 15% develop at least one of:
meningitis (PE signs negative)
encephalitis
cranial neuritis (often bilateral facial nerve palsy)
peripheral radiculoneuropathy (motor or sensory)
After weeks - months of onset, 8% will have cardiac manifestations (AV block mc, pericarditis, arrhythmias)
Stage 3: late, persistent infection (months to years after initial infection)
- arthritis mc, esp large joints (knee)
- chronic CNS disease; subacute, mild encephalitis, transverse myelitis, axonal polyneuropathy
- acrodermatitis chronica atrophicans (a rare skin lesion); reddish purple plaques and nodules on extensor surfaces of legs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Lyme disease diagnosis

A

clinical diagnosis: erythema migrans + tick exposure > lab confirmation + treat empirically
serologic studies: ELISA to detect serum IgM and IgG antibodies during the first month. Western blot to confirm positive or equivocal results

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Lyme disease treatment

A

Early localized disease:
confined to the skin - abx for 10 days
evidence of spread beyond the skin - extend to 20-30 days
Early lyme disease:
oral doxy x 21 days
amoxicillin and cefuroxime are alternative
erythromycin for preggos with penicillin allergies
Tx of complications (facial nerve palsy, arthritis, cardiac disease): prolonged abx x 30-60 days
Meningitis or other CNS complications: IV antibiotics x 4 weeks.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Rocky mountain spotted fever general info

A

Intracellular bacteria: Rickettsia Rickettsii
Ticks feeding on various mammals are vectors for transmission of disease
Major endemic areas: SE, midwestern, western US
Peak incidence: spring/summer months
patho: organism enters host cells via tick bite > multiply in vascular endothelium + spread to different layers of vasculature > damage to vascular endothelium > increased vascular permeability > activation of complement, microhemorrhages, microinfarcts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Rocky mountain spotted fever sxs

A

Sxs start 1 week after tick bite
Sudden onset of fevers, chills, malaise, myalgias, photophobia, headache, n/v
4-5 days of fever > papular rash starting peripherally (wrists, forearms, palms, ankles, soles) then spreads centrally (limbs, trunk, face) > becomes maculopapular then petechial
May lead to interstitial pneumonitis

18
Q

Rocky mountain spotted fever dx

A

primarily clinical
+- elevated LFTs, thrombocytopenia
Acute and convalescent serology and immunofluorescent staining of skin biopsy are confirmatory

19
Q

Rocky mountain spotted fever tx

A

doxycycline ~7 days
IV if patient vomiting
chloramphenicol for CNS manifestations or pregnant patients

20
Q

Epidural Abscess gen info

A

Contained purulent infection of the CNS.
Epidural abscesses may be either spinal or intracranial.
Bug: s aureus mc, strep, gram neg bacilli (e coli)
Both rare however incidence of spinal epidural abscess rising d/t spinal surgeries/interventions, indwelling IV catheters + assoc bloodstream infections, IVDU, immune system suppression.
Prompt diagnosis/management critical as delay in therapy may lead to permanent neuro damage.
Rfx: spinal procedures, IVDU, tattoos, sinus infection, URI, OM

21
Q

Epidural Abscess SXS

A

Spinal epidural classically: fever, back pain, progressive focal neurologic compromise (parasthesias, radicular pain, sensory/motor deficits, meningismus, loss of bladder/bowel function
Intracranial epidural abscess: fever, global or focal CNS dysfunction. +- neck pain, URI sxs
Red flags: cauda equina syndrome

22
Q

Epidural Abscess DX

A

classic presentations are rare, need a high index of suspicion and knowledge of risk factors
suspect SEA in patients with fever + back pain
suspect ICEA in patients with fever, AMS wwo focal neuro deficits
MRI preferred to localize + see extent, baseline labs, ESR/CRP, blood cultures before tx

23
Q

Epidural Abscess TX

A

Combined surgical and medical therapy needed for almost all cases
SEA: emergent surgical decompression if with neuro compromise (early decompression improves outcomes). Start abx before surgery > covering both MRSA and gram-negative bacilli (ceftazidime or cefepime)
culture results determine definitive abx tx > 6-8 weeks

24
Q

Cellulitis gen info

A

Inflammatory condition of skin and subQ tissue
Caused by a wide variety of bacteria, mc group A strep or S. aureus > often bug based on history
Bacteria gain entry thru breaks in skin: IVs, incisions, immersion in water, bites, wounds
chronic conditions: venous stasis diseases, lymphedema, diabetic ulcers
if untreated can lead to bacteremia
first determine purulent vs nonpurulent > severity of cellulitis based on presentation

25
Q

Cellulitis sxs and dx

A

inflammation: erythema, warmth, swelling, pain +- fever

clinical dx
blood cultures if w fever
tissue cx if w wound, ulcer, or site of infection
imaging (plain film, MRI) if suspicion of deeper infection

26
Q

Cellulitis tx

A

base treatment on suspected pathogen from hx
most require parenteral abx
should cover group A strep and MSSA (oxacillin, cefazolin)
MRSA only if suspected (vanc)
Continue IV abx until signs of infection improve then oral abx for 2 weeks

27
Q

Necrotizing fasciitis

A

Life-threatening infection of deep soft tissues that rapidly tracks along fascial planes.
extension of infection > thrombosis of microcirculation > tissue necrosis, discoloration, crepitus, and cutaneous anesthesia.
erythema & extreme pain out of proportion to PE → blue hemorrhagic bullae (blisters at site) → gangrene → septic shock +- crepitus. (Fournier gangrene - in the perineum +- scrotal involvement esp w impaired immunity (DM) after trauma to area.) lrinec score
May rapidly progress to sepsis, toxic shock syndrome (TSS), multi-organ failure.
Bug: s pyogenes, clostridium perfringens
Rfx: recent surgery, diabetes, trauma, IVDU
SXS: fever, pain out of proportion to appearance of skin in early stages > high index of suspicion
TX: abx alone not sufficient, NEED RAPID SURGICAL EXPLORATION AND DEBRIDEMENT
Broad spectrum parenteral abx tx
(carbapenem or pip tazo + MRSA coverage eg vancomycin or daptomycin + clinda)

28
Q

GNR Bacteremia gen info

A

Common sources: UTIs, intra-abdominal infections like colitis or cholangitis, pneumonia, central venous catheters
Bugs: E.coli, klebsiella pneumoniae, enterobacter spp, pseudomonas aeruginosa
Rfx: immune compromise, presence of indwelling catheter, recent abx use, housing in long term care facility, healthcare contact
Gram-negative pathogens a/w rapid systemic response due to endotoxin production
endotoxin (lipopolysaccharide) comprises about 75% of the outer membrane of GNRs > potent inducer of host defense cells, leading to
systemic inflammation: activation of proinflammatory mediators, hypotension, tissue damage, organ dysfunction, activation of coagulation cascade.
High levels of proinflammatory cytokines, tumor necrosis factor, and vasodilators lead to
apoptosis of endothelium cells in multiple organs,
increased vascular permeability and hypotension
hypoperfusion, manifesting as lactic acidosis, oliguria, and/or altered mental status
alterations in temperature
leukocytosis
tachycardia
tachypnea
depressed ventricular ejection fraction

29
Q

GNRs

A 
Klebsiella species
Escherichia coli
Enterobacter species
Pseudomonas aeruginosa
Haemophilus influenzae
Acinetobacter species
Neisseria meningitidis
Proteus species
Salmonella species
Serratia species
Brucella species
Campylobacter species
30
Q

GNR Bacteremia SXS

A

SIRS; fever, rigors, sweats, tachycardia, tachypnea, hypotension, AMS
Onset and shock may be rapid

31
Q

GNR Bacteremia DX

A

Blood cultures
Evaluation should include careful search for source of infection
Obtain follow-up cultures at 48-96 hours to document response to treatment
Most pathogens yield cx results within 48 hrs

32
Q

GNR Bacteremia TX

A

empiric abx asap
combination therapy when Pseudomonas or multi-drug resistant organism suspected
remove, drain, or debride any potential sources of infection like vascular or urinary catheters, intra-abdominal abscesses, obstructive cholangitis
duration of therapy varies with pathogen, adequacy of source control, and patient characteristics

33
Q

GNR or pseudomonas abx coverage

A 
pip-tazo
cefepime, ceftazidime
imipenem, meropenem
aztreonam
cipro, levofloxacin
gentamicin, tobramycin, amikacin
polymyxins
34
Q

S. Aureus bacteremia gen info

A

MC of bacteremia
Result from breaches in skin; indwelling catheters, post surgery, local infection like pna or cellulitis
Common complications > metastatic infections like endocarditis, embolization to CNS or other visceral organs, vertebral osteomyelitis, other bone/joint infections

35
Q

S. Aureus bacteremia SXS

A

Vary from asx to fever alone to sepsis

36
Q

S. Aureus bacteremia DX

A

2 sets of blood cx collected before abx
Evaluation should include a careful assessment for the source of infection, any potential removable foci of infection, such as an indwelling line, or metastatic sites of infection.
Echo if suss for IE

37
Q

S. Aureus bacteremia TX

A

Prompt source control and abx
Removal and/or debridement of any source or metastatic focus of infection, such as drainable abscesses and indwelling foreign bodies

MSSA: oxacillin, nafcillin, or cefazolin (if normal renal fxn)
MRSA: vancomycin, daptomycin
Minimum 14-day course can be considered in patients who defervesce and clear bacteremia within 72 hours, have no evidence of complications, and do not have indwelling catheters or prosthetic material, underlying malignancy, or immunocompromise.
All others should be treated with 4-6 weeks of antibiotics.

38
Q

Syphilis

A

path: t. pallidum
1: singular ulcer
painless
+LN non-tender
2: fever + rash
targetoid
palms/soles
3: neurosyphilis
tabes dorsalis
argyll robertson

DX
1: darkfield microscopy
2: RPR > FTA-ABS
3: LP > CSF RPR > CSF FTA-ABS

TX
1: PCN x 1 IM
2: PCN x 1 IM
EL: PCN x 1 IM
LL: PCN IM qwk x 3 wks
3: PCN IV q4h x 10-14 days

39
Q

LGV

A

Lymphogranuloma venereum (LGV) is a sexually transmitted infection caused by a particular strain of chlamydia bacteria
path: c trachomatis
singular
painless
+LN tender
suppurative, drainage

DX: NAAT
TX: doxy

40
Q

Chancroid

A

path: h. ducreyi
singular
painful
+LN tender
dx: gram stain + cx
tx: azithro or cipro

41
Q

Herpes

A

path: hsv1, hsv2, DRG
painful burning prodrome
painful vesicles on erythematous base
coalesce = ulcer
dx: pcr
tx: acyclovir or valacyclovir

Medicine Refresher (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions