Infection of bones n joint

Question 1

3 bone and joint Infections

Answer 1

1. Infectious Arthritis
2. Osteomyelitis
3. Infections with Prostheses of Bones and Joints

Question 2

Clinical features of acute infection

Answer 2

•90% monoarticular
•60-80% fever-usually mild
•Knee most common site, then hip
•sternoclavicular-consider IVDA
•10% polyarticular-underlying RA

Question 3

Clinical presentation acute

Answer 3

•JOINT EFFUSION
•JOINT CONTRACTURE
FLEXION
•PAINFUL MOTION
•TEMP 39-40 Celcius

Question 4

Laboratory finding for bone and joints infections

Answer 4

• elevated ESR
• synovial fluid
– turbid
•–>50K WBC, 75%PMN’s,
– low glucose-bacterial, also RA,
crystaline disease

Laboratory findings

•Bacteriology
–joint fluid gram stain + 1/3
–joint fluid culture + >90%
–blood culture + 10-60%
–synovial tissue culture-mycobacteria,fungi

Question 5

Etiology and causes of infections

Answer 5

most common:
Staphylococcus aureus
• adults <30 Gonococcal
• children - H. influenzae, Salmonella
• neonates, elderly, DM, Group B Streptococcus
• elderly,chronic disease,
•UTI Gram negative rods
• IVDA - P.aeruginosa, sternoclavicular joints

Etiology
•Bite
•human-oral strep, anaerobes
•cat,dog-Pasteurella
•rat-Streptobacilus moniliformisl
–Intermittent, migratory polyarthritis, knee
•Lyme (chronic), GC (faster)
•Chronic
•TB, atypical mycobacteria, fungi-spores, blasto, cocci,histo

Question 6

What is gonococcal arthritis

Answer 6

Gonococcal arthritis-2 forms
•Disseminated
•–fever,chills
––skin lesions-papules/ petechiae/ pustules
––polyarticular with bacteremia.
––Organism in skin scrapings.
––Negative synovial culture
»Monoarticular
•More like routine bacterial, suppurative infection
•positive synovial culture, may have preceding history like disseminated form

Question 7

Viral causes of arthritis

Answer 7

Viral Causes of arthritis

•Rubella
–Women, with rash
–Self limited, usually hands
–vaccine induces arthritis in 40% post pubertal women
•Hepatitis B
–up to 20%, symmetric
–early-resolves with onset jaundice
•Mumps
–onset with parotitis
•Parvovirus B19
–women, Erythema infectiosum
–Late winter, spring
–Arthropod borne
–Lymphocytic choriomeningitis virus
–severe flu-like ilness with headache
•HTLV-1
•HIV

Question 8

Pathogenesis of infectious arthritis

Answer 8

•Usualy hematogenous
•Predisposing factors
•–pre-existing arthritis
•–trauma-interruption of capillary integrity
•–systemic diseases-malignancy, DM, immunosuppressive therapy

Question 9

Definition osteomyelitis

Answer 9

•Osteomyelitis is a bone infection usually caused by bacteria, including mycobacteria, but is sometimes caused by fungi.

The original site of infection is elsewhere in the body,
and spreads to the bone by the blood.

Question 10

Pathophysiology of osteomyelitis

Answer 10

• Hematogenous spread
  Child- distal femur, proximal tibia
  Adult- axial skeleton
• Contigunous Spread
• In association with vascular insufficiency

Question 11

What diagnosis of osteomyelitis ( Radiograph 1)

Answer 11

MRI of the lower extremities of a 45 year old man with several weeks of leg pain and low grade fever. An abscess cavity is evident

Question 12

Dignosis of osteomyelitis , history and physical examination

Answer 12

History
- Presence if risk factor
- Symptoms of inflammation

Physical examination
- Signs of inflammation
-Decreased range of motion
- Drainage, sinus tract and ulceration

Question 13

Etiology and causes of osteomyelitis

Answer 13

-Bacteria or fungal spores may infect the bone directly through open fractures, during bone surgery, or from contaminated objects that pierce the bone. Staphylococcus aureus is the bacteria most commonly responsible. Mycobacterium tuberculosis (the main cause of tuberculosis) can infect the vertebrae to cause osteomyelitis

Question 14

Pathogenesis of infectious arthritis, osteomyelitis

Answer 14

-Usualy hematogenous
•Predisposing factors
•–pre-existing arthritis
•–trauma-interruption of capillary integrity
•–systemic diseases-malignancy, DM, immunosuppressive therapy

Question 15

Investigations for osteomyelitis

Answer 15

Investigations

•Blood cultures
•Bone biopsy (which is then cultured)
•Bone scan
•Bone x-ray
•C-reactive protein (CRP)
•Erythrocyte sedimentation rate (ESR)
•MRI
•Needle aspiration of the area around affected bones

Question 16

Laboratory Finding of Osteomyelitis

Answer 16

Laboratory Investigations
•Elevations in the erythrocyte sedimentation rate (ESR—a test that measures the rate at which red blood cells settle to the bottom of a test tube containing blood),
•elevated level of C-reactive protein (a protein that circulates in the blood and dramatically increases in level when there is inflammation usually occur.
• elevated levels of white blood cells.
•these blood tests are not sufficient to diagnose osteomyelitis.

Question 17

Radiology Investigation osteomyelitis

Answer 17

Radiological Investigation
•An x-ray may show changes characteristic of osteomyelitis, but sometimes not until more than 3 weeks after the first symptoms occur.
• Computed tomography (CT) and magnetic resonance imaging (MRI) can also identify the infected area

-The infected area almost always appears abnormal on bone scans (images of bone made after injecting radioactive technetium),

-llustration of the results of an external wound that
destroys periosteum and allows bacteria to colonize the cortical bone surface. The medullary circulation

Question 18

What antibiotics use for bone and joints infections

Answer 18

Antibiotics

•MSSA-oxacillin(+ rifampin)
•MRSA-Vancomycin(+ rifampin)
•Enterococcus-ampicillin/vancomycin, plus aminoglycoside for significant part of time
•Gram-(including GC & H Flu)-ceftriaxone/ cefotaxime/ ciprofloxacin
•Pseudomonas-ceftazidime(or pipercillin) + aminoglycoside/ quinolone