musculoskeletal infections & TB Flashcards
infection of skin, subcutaneous, fat, or connective tissue (soft tissue infection)
cellulitis
infection of bone (marrow spaces)
osteomyelitis
infection of joint (synovial tissue, articular surfaces)
septic arthritis
group of people prone to infections by unusual organisms at unusual sites
drug addicts
most common organism for musculoskeletal infections
staph. aureus
most common route of dissemination for musculoskeletal infections
hematogenous
growth plates inhibit what route of dissemination
hematogenous.
most common locations for musculoskeletal infections
knee, hip, ankle (distal tibia), shoulder, spine
two major categories of musculoskeletal infection
suppurative (pus, staph.), non-suppurative (TB)
bone marrow infectino by pyogenic non-TB organism
suppurative osteomyelitis
clinical features of acute infection
edema, lymphadenopathy, warm skin, cellulitis, joint pain
4 radiographic stages of infection
latent stage (1-10 days), early stage (days 10-21), middle stage (weeks), late stage (months)
symptoms of early stage infection
soft tissue swelling, displaced lucent fat planes that become mass like, osteopenia
characteristics of middle stage infection
permeative or lytic moth-eaten destruction and periosteal response; solid, laminated, codman’s trianlge
characteristics of late stage infection
cortical destruction, draining sinus, involucrum, cloaca, sequestrum, sclerosis, debris, loss of joint space, ankylosis, chrinoic imcomplete resolution, immune deficient
chalky, white area representing isolated dead bone; cortical and medullar infarcts
sequestrum
chronic periosteal response. pus lifts the periosteum and causes new one formation that tries to wall off the infection.
involocrum
bony collar
involocrum
draining sinus, more common with chronic disease
cloaca
a rare complication of cloaca is to develop a squamous cell carcinoma with malignant transformation has been called
marjolin’s ulcer
localized, aborted form of suppurative osteomyelitis that has localized pain worse at night and relived by aspirin
brodie’s abscess formation
mimics osteoid osteoma. located in the distal tibia.
brodie’s abcess
chronic osteomyelitis and reactive sclerosis
brodie’s abcess
respects growth plates/fascial plane
tumor
does not respect growth plate or joint spaces
infection
prognosis of infection
much better detection and treatment today, absolutely require antibiotic management
infection of vertebral body
spondylitis
risk factors for osteoporosis
female, older than 70, caucasian or asian, early onset of menopause, longer postmenopausal interval, inactivity, especially lack of weight bearing exercise
modifiable risk factors for osteoporosis
smoking, alcohol abuse, excessive caffeine consumption, excessive dietary protein consumption, lack of dietary calcium, lack of sunlight exposure (to generate endogenous vit D)
what is the tear drop distance normally
9 - 11 mm
what are the hip fat planes
gluteus medius, obturator internus, iliopsoas
early radiographic features of spine infection
rapid loss in disc space, endplate destruction
upper limit size of the retro-tracheal interspace (RTI)
22mm
upper limit size of the retro-pharyngeal interspace (RPI)
7mm
water is white on which film
T2 weighted MRI
fat is white on which flim
T1 weighted MRI
most common cause of suppurative osteomyelitis
staph. aureus
TRUE or FALSE: both infections and tumors respect epiphyseal growth plates
FALSE: tumors respect the boundary but infections do not
disc space loss with endplate destruction is a classic example of
spine infection
what are examples of risk groups for bone infection
immunosupressed, diabetic, post surgical, vascular insufficiency, sickle celll anemia, IV drug users
some organisms that cause bone infection and the most common
STAPH. AUREUS (90%), mycobacterium TB, neisseria gonorrhea, pseudomonas, fungus, strep. Pyogenes
what are some modes of infection
trauma/post surgical, UTI, pneumonia, skin infections, open wound or cellulitis, heel sticks in infants
routes of dissemination for bone infection including the most common
HEMATOGENOUS (MC), direct extension, direct implantation, postoperative
growth plates inhibit which type of dissemination/spread
hematogenous; children are affected less than adults or infants
a study done that is sensitive to metabolic activity and increased vascular supply
bone scan
what is the most important diagnosis to consider when a patient presents with unilateral sacroilitis
infection
what exam is needed if there is loss in disc space and endplate destruction
think infection so; MRI
what are some osteomyelitis findings on an MRI
decreased signal intensity on T1, increased signal intensity on T2
most common cause of infection-related death world wide
TB
most common type of TB
secondary
most common location of TB in the spine
TL junction
first radiographic finding of TB in an adult
earliest - anterior disc space narrowing.
phemster’s triad is indicative of
TB septic arthritis
phemster’s triad
juxtarticular osteoporosis, marginal erosions, slow joint space loss
type of TB found in the spine, involving multiple levels with paraspinal cold abcesses, has slower progression of joint destruction, and has a poorer response to therapy
non-suppurative; as opposed to suppurative
kyphotic angulation associated with TB
gibbus formation
TB associated with the spine
pott’s disease