Musculoskeletal Infections - Skin and soft tissue, Septic Arthritis

Question 1

Skin infections are split into what two types?

Answer 1

Purulent and not purulent

Question 2

What is comedo?

Answer 2

pimple, simplest staph infection of the skin, involves sebaceous gland and/or hair follicle of a single skin unit

Question 3

What is folliculitis?

Answer 3

involves hair and associated structures

Question 4

What is a furuncle?

Answer 4

deep inflammatory nodule (abscess, boil) involving a single entire skin structure

Question 5

What is a carbuncle? How is it treated?

Answer 5

more extensive furuncle, whereby infection has spread to subcutaneous fat; not usually amenable to drainage alone, systemic antibiotics frequently needed

Question 6

What is bullous impetigo?

Answer 6

large, fluid filled blisters, may represent a secondary bacterial infection complicating a preexisting skin lesion, usually requires systemic antibiotics

Question 7

Abscess/wound infection frequently caused by?

Answer 7

S. aureus, patient`s own flora

Question 8

What is scalded skin syndrome?

Answer 8

Widespread bullae and exfoliation, primarily due to exfoliative exotoxin from S. aureus in newborns and children

Question 9

How is scalded skin syndrome distinguished clinically?

Answer 9

Nikolsky sign - lateral pressure on the skin results in separation of the dermal-epidermal junction

Question 10

What is toxic shock syndrome?

Answer 10

Staph producing a specific toxin cause systemic disease with edmea, hypotension, abdominal pain, and erythematous sunburn-like rash, healing characterized by desquamation of skin on hands/feet

Question 11

Non-purulent skin infections are classically associated with? More commonly associated with?

Answer 11

Clostridium perfringens, Streptococci

Question 12

Infection with C. perfringens is associated with:

Answer 12

Gas gangrene - pain, edema, local tenderness, also crepitation and dishwater discharge with palpation containing many organisms but few leukocytes

Question 13

Impetigo is caused by? Appears as? Treated with?

Answer 13

Simple streptococcal skin infection or S. aureus; honey or golden-crusted lesion; usually only need topical antibiotics

Question 14

Erysipelas/cellulitis is typically caused by what organism and what predisposing factors?

Answer 14

group A strep with predisposing trauma; associated with four cardinal signs of inflammation

Question 15

Most common in upper and lower extremity from what procedures?

Answer 15

infection involves lymphatics and deep dermal tissue, upper extremity in women due to axillary node resection, lower extremity saphenous vein harvesting

Question 16

Therapy of erysipelas/cellulitis requires what, in addition to systemic antibiotics?

Answer 16

Limb elevation

Question 17

What is ecthyma?

Answer 17

Similar to a furuncle without purulence, pain can be severe as it can signal more systemic involvement

Question 18

Necrotizing fasciitis is the most severe strep infection manifestation. What is the most important aspect of treatment, as this disease is known to invade muscle and fascia to spread along these planes?

Answer 18

Surgical debridement

Question 19

Streptococcal toxic shock is similar to staph toxic shock and is characterized by severe hypotension and multiple organ failure. What can usually be identified in these patients?

Answer 19

A focus of a soft tissue infection

Question 20

Synergistic necrotizing cellulitis/fasciitis is produced by multi-organism infections characterized by what? Caused by what organisms?

Answer 20

Present with simple would abscesses/cellulitis to profound systemic illness, multiple organ failure and crepitance; Fecal flora in addition to staph and strep

Question 21

Who is most at risk for synergistic necrotizing cellulitis/fasciitis? Treatment?

Answer 21

Diabetic or vascular insufficieny patients; broad spectrum antibiotics with thorough debridement

Question 22

What are all the infective agents that cause chancriform lesions?

Answer 22

Treponema pallidum, Haemophilus ducreyi, Sporothrix, Bacillus anthracis, Francisella tularensis, Atypical mycobacteria (marinum and ulcerans)

Question 23

What causes membranous ulcers? Vascular papules/nodules?

Answer 23

Corynebacterium diphtheriae; Bartonella sp.

Question 24

What causes annular erythema? Acne? Pyoderma gangrenosum?

Answer 24

Borrelia burgdorferi; Propionibacterium acnes; immune-mediated, seen in patients with systemic illness or autoimmune diseases

Question 25

Diabetic foot infections can cause:

Answer 25

Paronychia, cellultis, myositis, abscess and osteomyelitis

Question 26

Unprovoked animal bites should prompt suspicion and evaluation for what infection? Are provoked bites uncommon?

Answer 26

Rabies; No

Question 27

Percentage of dog bites that become infected? Cat bites? Possible pathogens?

Answer 27

2 to 10; 80; Pasteurella, S. aureus, Bacteroides, Fusobacterium, and Capnocytophaga

Question 28

What are the most likely infected sites of infectious arthritis in infants? Children?

Answer 28

Hips; Knees

Question 29

Why is bacterial arthritis hematogenously spread?

Answer 29

The synovial membrane lacks a limiting basement membrane and is therefore susceptible to bacteria deposit in bacteremia

Question 30

True False: Septic arthritis is a common outcome of knee arthroscopy

Answer 30

False

Question 31

Non-gonococcal septic arthritis is monarticular in 80 to 90 percent of cases. What does its presentation consist of?

Answer 31

pain and loss of function of one or more joints - typical arthritis, with focal joint tenderness, inflammation, and effusion, also limited passive and active range of motion

Question 32

Most common cause of acute septic arthritis in all age groups? Elderly, IV drug users, and immunocompromised?

Answer 32

S. aureus but streptococci frequently; all groups afflicted by gram negative organisms

Question 33

Diagnostic laboratory findings? How reliable is synovial fluid culture in nongonococcal infection?

Answer 33

Elevated ESR and CRP, fluid aspirated from septic joints >50,000 cell with over 90 percent PMN leukocytes, infection is highly likely, synovial fluid culture yields bacterial growth 80 to 90 percent

Question 34

Gonococcal arthritis commonly involves which joints and what is present in 1/3 of patients?

Answer 34

Knee, ankle, wrist, and hand joints; Tenosynovitis

Question 35

What is the most common clinical presentations of arthritis in DGI?

Answer 35

Migratory polyarthralgia, with pustular dermatitis, tenosynovitis, with small papules on trunk or extremities

Question 36

Aspiration of a joint infected with N. gonorrhoeae yields the organism what percentage of the time?

Answer 36

50 percent

Question 37

Cultures of N. gonorrhoeae is much higher from mucosal sites than blood or synovial fluid. How often are cultures positive in cervical swabs in women and urethral swabs in men?

Answer 37

80 to 90 percent; 50 to 70 percent

Question 38

What is essential in determining treatment of septic arthritis?

Answer 38

Gram stains and culture

Question 39

How long is treatment in septic arthritis?

Answer 39

4 to 6 weeks, like osteomyelitis

Question 40

What should you be careful of with patients who have arthritis?

Answer 40

Potential of infection with organism must be considered and treated until its absence is clear