Muskuloskeletal System- Muscle Infections Flashcards
muscle infection caused by a bacteria, fungus, parasite, or virus
Infectious myositis
necrotic infection caused by C. perfringens, other Clostridia
Gas gangrene
non-clostridial necrotic infection caused by mixed aerobes, anaerobes
Synergistic myositis
refers to a bacterial infection of skeletal muscle that leads to abscess formation
Pyomyositis
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
Necrotizing fascitis
infection due to a polymicrobial mix of organisms (GAS, S. aureus, Enterobacteriales, & anaerobes)
Type I Necrotizing Fascitis
also known as hemolytic streptococcal gangrene; due to infection with GAS
Type II Necrotizing Fascitis
most common pathogens in muscle infections:
-S. aureus
-BHS
-S. pneumonia
-Enterobacterales
-Pseudomonas & other GNB
-many anaerobes (C. perfringens causes gas gangrene)
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
Rhabdomyolysis
-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”
Actinomycosis
branched gram positive bacilli that looks like hyphae microscopically; anaerobic and is not acid fast
Actinomyces
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
Mycetoma
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
Nocardia
a mycetoma infection formed in the foot
Madura foot
a parasitic organism that causes infection after eating a larvae in undercooked WILD GAME MEAT
Trichinella
causes infection after eating eggs on unwashed food or self inoculation; causes Cysticercosis
Taenia solium
causes infection after coming into contact with cat faeces, eating undercooked meat with parasite in tissue cysts, or from mother to baby
Toxoplasma gondii
appropriate myositis specimens
-Muscle/tissue or needle biopsy of tissue
-Abscess aspirate
least appropriate specimen because may be contaminated by normal skin flora; placed in appropriate transport media to maintain both aerobic and anaerobic organisms
Abscess swab
_______ ________ are positive in only 5-35% cases since bacteremia is often transient
Blood cultures
Specimen processing:
-Direct gram stain done on all specimens except _______ _________
Blood culture
