1. Microbiology of Bone & Joint Infections

2. Myositis
Myositis refers to any condition causing inflammation in one or more muscles
Weakness, swelling, and pain are the most common myositis symptoms
Myositis causes include infection, injury, autoimmune conditions, and drug side effects
Treatment of myositis varies according to the cause

3. Causes of Myositis
Myositis is caused by any condition that leads to inflammation in the muscles
Myositis causes can be divided into several major categories:
Inflammatory conditions causing myositis
Myositis caused by microbial infection
Myositis caused by drugs
Myositis due to injury

4. Myositis caused by microbial infection
Known pathogens include the following:
Viral
HIV (one of the most common causes of myositis), HTLV-1, Cytomegalovirus, Coxsackie B virus (epidemic myalgia), Influenza
Bacterial
S. aureus (most common, 70%); Streptococcus viridans; Salmonella enteritidis; Neisseria species , Yersinia species

5. Spirochetal Mycobacterial Parasitic Fungal Borrelia burgdorferi
Mycobacterium avium
Parasitic
Echinococcus granulosus, Taenia solium, T. cruzi
Fungal
Cryptococcus neoformans, Candida species, Histoplasma capsulatum, Aspergillus species

6. Symptoms of Myositis
The main symptom of myositis is muscle weakness that may be detectable with testing
Muscle pain (myalgias)
Dermatomyositis, polymyositis
The weakness affects large muscle groups
including the neck, shoulders, hips, and back
Dermatomyositis
Dermatomyositis (DM) is a connective-tissue disease related to polymyositis (PM) that is characterized by inflammation of the muscles and the skin

7. Dermatomyositis

8. The weakness from myositis can lead to falls
make it difficult to get up from a chair or after a fall
Other myositis symptoms that may be present with inflammatory conditions include:
Rash
Fatigue
Thickening of the skin on the hands
Difficulty swallowing
Difficulty breathing

9. Diagnosis of Myositis Blood tests
Magnetic resonance imaging (MRI scan)
Electromyography (EMG)
Muscle biopsy

10. Osteomyelitis Osteomyelitis is an infection in a bone
Infections can reach a bone by traveling through the bloodstream or spreading from nearby tissue
Osteomyelitis can also begin in the bone itself if an injury exposes the bone to germs
Osteomyelitis of the tibia of a young child

11. In children
most commonly affects the long bones of the legs and upper arm
In adults
more likely to develop osteomyelitis in the bones that make up the spine
People who have diabetes may develop osteomyelitis in their feet if they have foot ulcers
Plantar foot ulcers with a deep space infection

12. Most people require surgery to remove parts of the bone that have died
Once considered an incurable condition, osteomyelitis can be successfully treated today
Most people require surgery to remove parts of the bone that have died
followed by strong antibiotics
often delivered intravenously
typically for at least six weeks

13. Symptoms Signs and symptoms of osteomyelitis include: Fever or chills
Irritability or lethargy in young children
Pain in the area of the infection
Swelling, warmth and redness over the area of the infection

14. Causes
Most cases of osteomyelitis are caused by staphylococcus bacteria
Germs can enter a bone in a variety of ways, including:
Via the bloodstream
From a nearby infection
Direct contamination

15. From a nearby infection
Via the bloodstream
Germs in other parts of the body can travel through bloodstream to a weakened spot in a bone
From a nearby infection
Severe puncture wounds can carry germs deep inside the body
If such an injury becomes infected, the germs can spread into a nearby bone

16. Direct contamination
This may occur if a bone have broken so severely that part of it is sticking out through skin
Direct contamination can also occur during surgeries to replace joints or repair fractures

17. Disease causative agent
Age group
Most common organisms
Newborns (younger than 4 mo)
S. aureus, Enterobacter species, and group A and B Streptococcus species
Children (aged 4 mo to 4 y)
S. aureus, group A Streptococcus species, Haemophilus influenzae, and Enterobacter species
Children, adolescents (aged 4 y to adult)
S. aureus (80%), group A Streptococcus species, H. influenzae, and Enterobacter species
Adult
S. aureus and occasionally Enterobacter or Streptococcus species
Sickle cell anemia patients
Salmonella species are more common in patients with sickle cell disease than in normal patients. However, S. aureus is still most likely to occur.

18. Acute Osteomyelitis
Vertebral osteomyelitis can occur in adults secondary to a UTI or prostatitis
Candidemia from infected central venous catheters can lead to fungal osteomyelitis
Contiguous infection
Bacteria related to primary focus, it includes
Gram positive cocci, Gram negative bacilli, Anaerobes, and Poly-microbial infection

19. Risk factors Bones are normally resistant to infection
For osteomyelitis to occur, a situation that makes your bones vulnerable must be present
Recent injury or orthopedic surgery
A severe bone fracture or a deep puncture wound
Surgery
Deep animal bites

20. Circulation disorders
When blood vessels are damaged or blocked
What begins as a small cut can progress to a deep ulcer that may expose deep tissue and bone to infection
Diseases that impair blood circulation include
Poorly controlled diabetes
Peripheral arterial disease
often related to smoking
Sickle cell disease
Peripheral vascular disease

21. Problems requiring intravenous lines or catheters
Examples of when this type of tubing might be used include
Dialysis machines
Urinary catheters
Long-term intravenous tubing

22. Conditions that impair the immune system
Factors that may suppress your immune system include
Chemotherapy
Poorly controlled diabetes
Having had an organ transplant
Needing to take corticosteroids
For unclear reasons
people with HIV/AIDS don't seem to have an increased risk of osteomyelitis
Illicit drugs
nonsterile needles
unsterilized skin before injections

23. Complications Osteomyelitis complications may include:
Bone death (osteonecrosis)
Septic arthritis
Impaired growth
Skin cancer
Osteonecrosis

24. Tests and diagnosis Blood tests Imaging tests Bone biopsy X-rays
Computerized tomography (CT) scan
Magnetic resonance imaging (MRI)
Bone biopsy

25. Treatments and drugs
The most common treatments for osteomyelitis are antibiotics and surgery to remove portions of bone that are infected or dead
Hospitalization is usually necessary

27. Medications
A bone biopsy will reveal what type of germ is causing the infection
The antibiotics are usually administered through a vein for at least four to six weeks
Side effects may include nausea, vomiting and diarrhea
An additional course of oral antibiotics may also be needed for more-serious infections

28. Surgery
Depending on the severity of the infection, osteomyelitis surgery may include one or more of the following procedures
Drain the infected area
Remove diseased bone and tissue
Remove any foreign objects
Amputate the limb

29. Arthritis Infectious Arthritis is inflammation of the joint space
Generally affects a single joint and result in suppurative inflammation
Hematogenous seeding of joint is most common
Pain, swelling, limitation of movement common symptoms

30. Etiology, Epidemiology & Risk factors
Gonococcal infection most common cause in young adults caused by Neisseria gonorrheae
Nongonococcal arthritis occurs in older adults

31. S. aureus is most common cause
Occasionally results from direct trauma, procedures (arthroscopy) or from contiguous soft tissue infection
S. aureus is most common cause
Other organisms : streptococci and aerobic Gram negative bacilli
Lyme disease in endemic areas
Risk factors: age, diabetes, immunosuppression, IV drug use, catheters, prior joint damage, sexually transmitted diseases

32. Diagnosis of Infectious Arthritis
History/examination to exclude systemic illness
Blood cultures
culture or DNA testing for N. gonorrheae
Urine may be used for DNA testing also
Culture of joint fluid, and skin lesions also indicated

33. Treatment & Management
Arthrocentesis with drainage of infected synovial fluid
Repeated therapeutic arthrocentesis often needed
Occassionally, arthroscopic or surgical drainage/debridement
Antimicrobial therapy should be directed at suspected and susceptibility results
Gonococcal arthritis: IV Ceftriaxone ( or Ciprofloxacin or Ofloxacin) then switch to oral Quinolone or Cefixime for 7-10 days

34. Nongonococcal infectiuos arthritis
MSSA: Nafcillin or Cefazolin.
MRSA: Vancomycin
Streptococci: Penicillin or Ceftriaxone or Cefazolin
Enterobacetriacae: Ceftriaxone or Fluroquinolone
Pesudomonas: Piperacillin and Aminoglycoside
Animal bite : Ampicillin-Sulbactam
Lyme disease arthritis: Doxycycline for 1 month

35. Prognosis & Complications
Gonococcal arthritis has an excellent outcome
Nongonococcal arthritis
can result in scarring with limitation of movement, ambulation is affected in 50% of cases
Risk factors for long–term adverse sequellae include
Age, prior rheumatoid arthritis, poly-articular joint involvement, hip or shoulder involvement, virulent pathogens and delayed initiation or response to therapy

36. Acne vulgaris Acne vulgaris (cystic acne or simply acne)
A common human skin disease
characterized by areas of scaly red skin, blackheads and whiteheads, and possibly scarring
Acne affects mostly skin with the densest population of sebaceous follicles
the face, the upper part of the chest, and the back

37. Signs and symptoms
Scars
Pigmentation

38. Cause Hormonal Genetic Psychological Infectious Diet
Different types of Acne Vulgaris: A: Cystic acne on the face, B: Subsiding tropical acne of trunk, C: Extensive acne on chest and shoulders.

39. Infectious Agent
Propionibacterium acnes (P. acnes) is the anaerobic bacterium species that is widely concluded to cause acne
Staphylococcus epidermidis has been universally discovered to play some role in acne formation

40. Medications Benzoyl peroxide Antiseptics Antibiotics Hormones
Topical retinoids
Oral retinoids
Anti-inflammatories
Benzoyl peroxide cream