Infections and AVN Flashcards
Infection of the skin.
Cellulitis
Infection of bone.
Osteomyelitis
Infection of joints.
Septic arthritis
Most common areas of infection in drug addicts.
“S” joints: Spine, SI joints, Symphysis pubis, SC joint
Most common infection.
Staphylococcus aureus
Most common route of administration.
Hematogenous
Gender and age bias of suppurative osteomyelitis.
Males aged 2-12
Most common locations of hematogenous spread.
Shoulder, hip, ankle, knee and spine
Two major categories of infection.
Suppurative (pus/staph) and Non-suppurative (TB)
4 radiographic stages.
Latent: 1-10 days
Early: 10-21 days
Middle: Weeks
Late: Months
One of the earliest radiographic signs that occurs in the early stage.
Soft tissue swelling
In what stage does permeative or moth-eaten destruction occur?
Middle
Least aggressive pattern of bone destruction.
Geographic
Most aggressive pattern of bone destruction.
Permeative
Chalky, white area representing dead bone.
Sequestrum
“Bony collar” or chronic periosteal response where pus lifts the periosteum, causing new bone formation.
Involucrum
The ulcerative channel with malignant transformation to squamous cell carcinoma within the cloaca.
Marjolin’s ulcer
Localized form of suppurative osteomyelitis that resembles an osteoid osteoma.
Brodies Abscess
Difference between tumor and infection in respect to growth plates.
Tumor: Respects growth plates, deflects fascial planes
Infection: Ain’t got no respect for GPs or joint spaces
Joint effusion, erosion, lytic destruction and juxtaarticular osteoporosis are all descriptors of?
Septic arthritis
Teardrop distance
> 11mm
Clinical impression of unilateral sacroiliitis? Bilateral?
Unilateral: Infection
Bilateral: AS
Most common age range for spinal infections.
> 20 years
Most common location of spinal infections.
Lumbar spine
Most common location of spinal infection in drug users.
SI joints
Sensitivity of plain films for osteomyelitis.
< 5%: Abnormal on presentation
< 33%: Positive for findings at 1 week
90% sensitivity at 3-4 weeks
Which test often follows MRI to evaluate soft tissue?
Bone scintigraphy
Which type of imaging is more sensitive for bone marrow pathologies?
MRI
Osteomyelitis findings on MRI.
Decreased signal on T1; Increased signal on T2
What is white on T1? T2?
T1: Fat white
T2: Water white
TB of the spine.
Pott’s disease
Most common cause of infection-related death worldwide.
TB
Most common location of secondary TB.
Spine T/L junction
Phemister’s Triad.
Juxtarticular osteoporosis, Marginal erosions, Slow joint space loss
Most common location for AVN.
Femur and humeral heads
4 stages of AVN.
Avascular, Revascularization, Repair, Deformity
Radiographic features of AVN.
Collapse of articular cortex, Fragmentation, Mottled trabecular pattern, Sclerosis, Subchondral cysts and Subchondral fx
Which signs are present when subchondral fractures are observed?
Rim sign and Crescent sign
Gender and age bias of AVN.
Males aged 30-70
AVN of the femur head is also known as?
“Chandler’s disease”
“Bite sign” is associated with?
AVN of the femur head
List all signs of AVN.
Snow cap sign, Crescent/Rim sign, Mushroom deformity and Hanging rope sign
Which sign of AVN is apparent during the repair phase?
Snow cap sign
Which sign of AVN is apparent during the healed phase?
Hanging rope sign
Which sign is apparent during the avascular/destructive phase?
Crescent/Rim sign
AVN of the femoral capital epiphysis before closure.
Legg-Calve-Perthes disease
Treatment for LCP disease.
Self-limiting; resolves in 2-8 years
Gender and age bias for Legg-Calve-Perthes disease.
Males 4-8 years old
What Roentgenometric finding is most common in LCP?
Increased Teardrop distance
Gender and age bias of Osteochondritis Dissecans.
Males age 11-20 years
Most common location of osteochondritis dissecans.
Knee (medial femoral condyle)
Idiopathic AVN of the knee that is more common in females.
SONK
What is an associated injury with SONK?
Medial meniscal lesions
Age and gender bias of Osgood-Schlatter’s disease.
Males aged 11-15 years
Disease that involves the inferior pole of the patella.
Sindig-Larsen-Johanssen disease
AVN of the metatarsal heads. Which MT head is most common?
Freiberg’s disease; MTP 2 is MC
Age and gender bias of Freiberg’s disease. Why?
MC in females aged 20-40 due to high heeled shoes
AVN of the lunate.
Kienbock’s disease
Age and gender bias of Keinbock’s disease.
Males aged 20-40
Possible treatment for Keinbock’s.
Silastic implants
Vascular insufficiency with localized pain and swelling of the tarsal navicular.
Kohler’s disease
Scheuermann’s disease is also known as:
Juvenile discogenic disease
How many contiguous vertebra are needed to diagnose JDD?
3
Looks like a crescent sign in the calcaneus.
Sever’s disease
A calcified medullary infarct is usually associated with what?
Arteriosclerosis
