INFECTION Flashcards
Males : Females = 3:1
Peak age range = 2‐12 years
KNOW
1–SUPPURATIVE OSTEOMYELITIS
The _______ is the most common bone
affected
• 90% due to ___________ ________
femur
Staphylococcus aureus
2—SUPPURATIVE OSTEOMYELITIS
Etiology (routes of spread)
1– ___________
– Most common route of spread
– organisms get into the blood stream, then settle out elsewhere in the body
2– _________ ________
– direct spread from another site of infection (soft tissue, joint, dental disease, etc.)
3—________ ________
– puncture wounds, penetrating injuries,
open fracture
4— Post‐operative
Hematogenous
Contiguous source
Direct implantation
3—SUPPURATIVE OSTEOMYELITIS
Clinical Features
Infantile = – commonly multi‐focal – PAIN and SWELLING in the region of infection – infant unwilling to move affected bone – \_\_\_\_\_\_\_ \_\_\_\_\_\_\_ common, esp. in the HUMERUS.
Childhood =
– MALES most commonly affected
– most common organism = _______ ________
– acute onset of symptoms
– local signs of inflammation, systemic signs of
infection
• Adult =
– more insidious onset
– ____ signs of inflammation, _______ signs of infection
Streptococcus group B
Staph. aureus
local
systemic
4—SUPPURATIVE OSTEOMYELITIS
Pathophysiology
‐ Predilection = Depends on vascular anatomy
A– Infantile
– seen from 0‐1 years
– vessels perforate the open growth plate
– ______OR_______ can be affected, as well as the joint
B–Childhood
– __________ is most common site of origin
– vessels don’t penetrate growth plate
– seen from 1‐16 years most common
C—Adult
– over 16 years of age (age depends on site of involvement)
– vessels penetrate the closed growth plate
– epiphyseal region and metaphysis can be involved, as well as ____ ______
epiphysis or metaphysis
metaphysis
the joint
5–SUPPURATIVE OSTEOMYELITIS
Pathophysiology‐ Progression
• If untreated, organisms can:
– deposit in medullary bone and multiply
– enter the cortex via Haversian and Volkman’s canals
– break through the cortex to the_______ region, spread underneath the periosteum disrupt normal blood supply resulting in _________
subperiosteal
necrosis
6–SUPPURATIVE OSTEOMYELITIS
Radiologic‐ Terminology
• ___________=
– necrotic bone separated from viable bone by
granulation tissue
• __________=
– living bone (periosteal reaction) that forms
around necrotic bone and attempts to wall
of the infection
•________=
– opening in involucrum that allows infected
region to decompress
Sequestrum
Involucrum
Cloaca
7–SUPPURATIVE OSTEOMYELITIS
Radiologic‐ EXREMITIES
A– _____ _______ changes
– see changes within 3 days of BONE infection
– localized SWELLING and fat plane displacement
– BLURRING of fat/muscle interface
– disruption of _______ _______ of the skin, if severe
– may see _____ w/certain organisms
B--\_\_\_\_\_\_\_ changes – 10 day latent period on x‐ray – permeative or moth‐eaten pattern of bone destruction – solid or laminated periosteal reaction – sequestrum, involucrum, cloaca
C– (Spinal changes primarily articular)
Soft tissue
normal contour
GAS
Osseous
8–SUPPURATIVE OSTEOMYELITIS
Complications
- Pathologic fractures
- Growth disturbances
- If joint involvement (_______ _______) then bony ankylosis can result.
- Malignant degeneration to squamous cell carcinoma (0.5%)
- _________ can lead to death
Treatment
- EARLY diagnosis is the key to successful treatment
- _______ _________ is the initial treatment of choice, often intravenous
septic arthritis
Septicemia
Antibiotic therapy
9–SUPPURATIVE OSTEOMYELITIS
ASSOCIATED ENTITIES
Brodie’s Abscess
• A sharply outlined focus of _____ ______ infection,
which may be sterile or contain residual of STAPH. organism
• See oval or serpiginous LUCENCY greater than 1cm
in diameter, and a variable zone of reactive sclerosis
• Likes the DISTAL tibia and knee
• D/DX: osteoid osteoma, osteoblastoma
• Treatment is ________ ________ and curettage
burned out
surgical decompression
10 OF 10—–SUPPURATIVE OSTEOMYELITIS
Advanced Imaging
• ___________
– TECHnetium and GALlium are common radionuclides
– look for HOT SPOT in region of suspected infection
***THE TECH GAL IS HOT
• _____
– sensitive and helpful for identifying extent of lesions
and any soft tissue involvement
– low signal, T1; high signal, T2
Scintigraphy
MRI
1–SEPTIC ARTHRITIS—-SUPPURATIVE
General information
– infection in a ________ ________
– organisms enter from DIRECT implantation, BLOOD or extension from adjacent bone infection
– SYNOVIAL involvement‐‐> capsular distention‐‐> cartilage death and destruction
– LOSS of cartilage causes joint destruction and bone involvement
– ________ _________ is common
• ____________ is common in dirty needle users
– likes the “S” joints
• Spine
• Sacroiliac
• Sternoclavicular
joint space
Staph aureus
Pseudomonas
2–SEPTIC ARTHRITIS—-SUPPURATIVE
Clinical features
– DECREASED ROM due to PAIN and ______ _______
– may see fever, chills, erythema
– labs show elevated _____, leukocytosis and positive culture
capsular edema
ESR
3–SEPTIC ARTHRITIS—-SUPPURATIVE
Radiologic findings
A–• Note: changes occur _________ compared to other inflammatory processes
B–• Soft tissues
– distention of capsule
– _________ of the joint space early on, LOSS of space in a few weeks.
C–Radiologic findings‐ osseous
– ________ osteopenia
– subchondral bone DESTRUCTION
– osseous ankylosis of the affected joint (rare)
rapidly
widening
periarticular
1—SPINAL OSTEOMYELITIS SUPPURATIVE
Incidence
– only __-____% of skeletal infection involve the SPINE
–_______ spine most common region affected
– _____ _______ is the most common organism
Clinical features
– may find a history of previous VISCERAL infection or SURGERY
– insidious onset of ____ ______ is the m.c. complaint; may be RADICULAR
– fever is an uncommon finding, so clinical presentation may be misleading
2‐4
lumbar
staph. aureus
back pain
