IDMM investigations (3) Flashcards
what categories of inquiry make up a thorough physical exam?
- presenting complaint/HPI
- past medical Hx
- vaccinations
- travel/immigration
- assessment of risk behaviors
- animal/pet/occupation/environmental exposures
- meds (current and past) *antibiotic exposure in the last 6 months
what elements/systems must be examined on a thorough physical exam?
- general appearance
- CV/hemodynamic status
- skin
- lymph nodes
- eyes
- respiratory
- abdomen
- genital exam
- MSK
what is noted within HPI
duration
constitutional symptoms (associated)
fever/chills/rigors/night sweats etc…
weight loss
provocation/palliation
physical exam: general appearance
body habitus
urgency
distress
LOC
physical exam: CV/hemodynamic status
BP
perfusion
murmurs
physical exam: skin
color cyanosis rash scars wounds peripheral stigmata for deeper infections
physical exam: lymph nodes
lymphadenopathy
cervical, inguinal, axillary, extremity
physical exam: eyes
conjunctivitis
drainage
cellulitis (orbital, preorbital)
fundoscopic examinations
physical exam: respiratory
respiratory rate
auscultation (wheezes, crackles)
percussion resonance
physical exam: abdomen
tenderness
hepatosplenomegaly
physical exam: genital exam
genital/anal lesions
abnormal discharge
inguinal adenopathy
physical exam: MSK
joints spine (movement, tenderness, swelling)
list the 5 sites of infection
- SST
- respiratory
- GI tract (most in lower but some in upper)
- genitourinary tract
- sterile site
what can be tested for on a blood test?
WBC
hemoglobin
platelets
liver function tests
what does elevated WBC in a blood test indicate?
broad stimulation of immune response
what two factors on blood tests may be elevated in inflammation?
C reactive protein
erythrocyte sedimentation rate (ESR)
why do we we blood tests for procalcitonin?
it is released in response to bacterial toxins but downregulated in viral infections
helps differentiate cause of infection
what are the “acute phase reactants?”
what are they used for?
(on blood tests)
acute phase reactants = CRP and ESR
used for diagnosis of rheumatological conditions or for monitoring inflammation
what factors are assessed in urinalysis
- inflammation: WBCs, RBCs, leukocyte esterase
2. presence of bacteria: microscopy, nitrite
list indications for urinalysis
- complicated infection
- atypical symptoms
- failure to respond to therapy
- recurrent symptoms less than one month after previous
how are urine cultures quantified?
by CFU (colony forming units)
this is unlike other cultures
the test is significant if >100 000 CFU/mL (+symptomatic +pyuria)
mixed infections are rare
list the specimen types used in microbiologic analysis
virus typical bacteria atypical bacteria fungi parasite
what are the two diagnostic methods for microbiological analysis
- microscopy
2. gram stain
are gram stains done on urine or stool
no
what is the purpose of microscopy
can ID all groups of pathogens, based on stains, size, shapes
what is the purpose of gram stain
MOST IMPORTANT
automatically performed on respiratory and wound tissue/fluid samples and blood samples
can indicate presence of inflammation, amount of organisms and presumptive ID
what are some limitations of susceptibility testing
- breakpoints can be unclear
- in vitro may not predict final outcome in vivo (due to pharmacodynamic and pharmacokinetics)
- MIC measurements are not always reliable
- other host factors (i.e immune system)
on which tissues is gram staining used?
NOT on stool
NOT on urine
yes on respiratory (though often contaminated with oral flora), SST, genital and sterile site samples
on which tissues is culture and sensitivity used?
on all tissues, though less on genital
on what suspected pathogen samples is microscopy used?
NOT on viruses
yes to bacteria, atypical bacteria, fungi and parasites
on what suspected pathogen samples is culture used?
sometimes on viruses
yes on bacteria, atypical bacteria and fungi
NOT on parasites
on what suspected pathogen samples if nucleic acid testing used?
YES on viruses
sometimes on bacteria/atypical bacteria
NOT on fungi or parasites
on what suspected pathogen samples if antigen testing used
sometimes on viruses, atypical bacteria, fungi and parasites
NOT on typical bacteria
on what suspected pathogen samples is serology testing used?
YES on viruses
NOT on bacteria
sometimes on atypical bacteria, fungi, parasites
what is the nucleic acid amplification test
it is a molecular identification method
PCR = one quick method to test for nucleic acids
advantages = sensitive, specific, quick
disadvantages = limited to specific target, may not detect viable organisms and expensive
list some antigen detection methods
ELISA
EIA
western blot
cytotoxin assays
advantages = quick, specific
disadvantages = poor sensitivity, limited to specific target, may not detect viable organism
list some antibody detection methods
serology
IGRA
TB skin test
