Muskuloskeletal System- Muscle Infections

Question 1

muscle infection caused by a bacteria, fungus, parasite, or virus

Answer 1

Infectious myositis

Question 2

necrotic infection caused by C. perfringens, other Clostridia

Answer 2

Gas gangrene

Question 3

non-clostridial necrotic infection caused by mixed aerobes, anaerobes

Answer 3

Synergistic myositis

Question 4

refers to a bacterial infection of skeletal muscle that leads to abscess formation

Answer 4

Pyomyositis

Question 5

a rare but more serious, infection of muscles, subcutaneous fat, superficial fascia, overlying soft tissues; spreads widely, rapidly & can be fatal in a very short time

Answer 5

Necrotizing fascitis

Question 6

infection due to a polymicrobial mix of organisms (GAS, S. aureus, Enterobacteriales, & anaerobes)

Answer 6

Type I Necrotizing Fascitis

Question 7

also known as hemolytic streptococcal gangrene; due to infection with GAS

Answer 7

Type II Necrotizing Fascitis

Question 8

most common pathogens in muscle infections:

Answer 8

-S. aureus
-BHS
-S. pneumonia
-Enterobacterales
-Pseudomonas & other GNB
-many anaerobes (C. perfringens causes gas gangrene)

Question 9

a disease involving breakdown of skeletal muscle tissue
-usually due to a traumatic crush injury, muscle exertion or alcohol abuse
-causes death of muscle fibres & the end products are released into bloodstream
-muscle proteins appears in urine-complications can be kidney failure

Answer 9

Rhabdomyolysis

Question 10

-chronic infection by a gnb that branch, looks like hyphae microscopically so were once thought to be a fungus
-characterized by abscess formation which emit yellow “sulphur granules”

Answer 10

Actinomycosis

Question 11

branched gram positive bacilli that looks like hyphae microscopically; anaerobic and is not acid fast

Answer 11

Actinomyces

Question 12

caused by nocardia or fungus; occurs mostly in tropical/ sub-tropical climates, usually after organism gets in via a puncture wound;
-chronic destructive process of skin, subcutaneous tissue, muscle and bone
-granulation tissue develops with draining sinus & presence of dark brown, black melanotic granules

Answer 12

Mycetoma

Question 13

obligate aerobic, beaded, branching, gpb; found in standing water, decaying plants, and soil;
-infection is via inhalation of the bacteria or by direct inoculation of the skin through a cut;
-strict aerobe and partially acid fast

Answer 13

Nocardia

Question 14

a mycetoma infection formed in the foot

Answer 14

Madura foot

Question 15

a parasitic organism that causes infection after eating a larvae in undercooked WILD GAME MEAT

Answer 15

Trichinella

Question 16

causes infection after eating eggs on unwashed food or self inoculation; causes Cysticercosis

Answer 16

Taenia solium

Question 17

causes infection after coming into contact with cat faeces, eating undercooked meat with parasite in tissue cysts, or from mother to baby

Answer 17

Toxoplasma gondii

Question 18

appropriate myositis specimens

Answer 18

-Muscle/tissue or needle biopsy of tissue
-Abscess aspirate

Question 19

least appropriate specimen because may be contaminated by normal skin flora; placed in appropriate transport media to maintain both aerobic and anaerobic organisms

Answer 19

Abscess swab

Question 20

_______ ________ are positive in only 5-35% cases since bacteremia is often transient

Answer 20

Blood cultures

Question 21

Specimen processing:
-Direct gram stain done on all specimens except _______ _________

Answer 21

Blood culture