Exam 6 infectious disease

Question 1

What is necrotizing fasciitis?

Answer 1

an infection leading to the necrosis of subcutaneous tissue; severe pain is common

Question 2

How should you treat necrotizing fasciitis?

Answer 2

aggressively through surgery and IV antibiotics and fluids

Question 3

What is acute infectious arthritis?

Answer 3

rapidly progressing joint infection, usually bacterial in origin

Question 4

What is osteomyelitis?

Answer 4

Inflammation and destruction of bone caused by bacteria, mycobacteria, or fungi, causes localized bone pain and tenderness

Question 5

What usually causes osteomyelitis?

Answer 5

contiguous spread or from open wounds

Question 6

What is myositis?

Answer 6

Infection of the muscle that leads to muscle inflammation

Question 7

What usually causes necrotizing fasciitis?

Answer 7

beta-hemolytic group A Streptococcus (S. pyogenes) and sometimes S. aureus

Question 8

What do most patients have prior to a necrotizing fasciitis infection?

Answer 8

recent minor trauma, surgery, or varicella infection

Question 9

What is the tree for S. pyogenes?

Answer 9

Gram+ cocci in chains, Catalase (-), Beta hemolytic, Bacitracin sensitive

Question 10

What does necrotizing fasciitis typically present with clinicallY/

Answer 10

High fever and heart rate, altered mental status, low blood pressure, leukocytosis, positive blood cultures, will have rapid onset, high CRP and ESR, high WBC and banded neutrophils

Question 11

What would you do to diagnose/treat necrotizing fasciitis initially?

Answer 11

gram stain wound, culture the wound, surgical debridement of necrotic tissue

Question 12

What organism classically causes necrotizing fasciitis in immunocompromised individuals?

Answer 12

S. pyogenes

Question 13

T/F: Erythrocyte sedimentation rate (ESR) is a non-specific indicator of tissue damage and inflammation?

Answer 13

True; it’s non-specific

Question 14

When in ESR usually elevated?

Answer 14

Anemia, endocarditis, kidney disease, osteomyelitis, pregnancy

Question 15

What is C-reactive protein involved in?

Answer 15

promotion of immune system through activation of the complement cascade; Upregulated due to cytokines released by leukocytes

Question 16

when is CRP usually elevated?

Answer 16

bacterial infections, inflammation, acute rheumatic fever/arthritis, inflammatory bowel disease

Question 17

Explain the classing system of synovial fluid

Answer 17

Synovial fluid should be clear/whitish. The more opaque it becomes the more it increases in class. Class IV has blood cells in it due to a ruptured synovial joint and its associated blood vessels

Question 18

What usually causes acute infectious arthritis?

Answer 18

Typically S. aureus in older adults, N. gonorrhea in sexually active young adults

Question 19

What do pts with acute infectious arthritis usually present with?

Answer 19

Rapid onset, personal history (sexually active/recent surgery), pain, limited ROM, synovial fluid analysis will be abnormal, positive blood cultures

Question 20

What is the tree of Staphylococcus aureus?

Answer 20

Gran + cocci in clusters, Catalase (+), Coagulase (+)

Question 21

What is the trea of Neisseria gonorrheae?

Answer 21

Gram- diplococci intracellular, Oxidase +, Only oxidizes glucose

Question 22

What to pts with osteomyelitis typically present with?

Answer 22

Fever, high pulse, overlying skin is warm and red with multiple necrotic-appearing lesion, high ESR, CRP, WBC (some banded neutrophils)

Question 23

What classically causes osteomyelitis of the spinal cord upon reactivation?

Answer 23

TB

Question 24

How should osteomyelitis be treated

Answer 24

Antibiotic against specific pathogen

Question 25

What are the main culprits of osteomyelitis?

Answer 25

S. aureus, Salmonella typhii, Pasteurella multocida

Question 26

What can cause osteomyelitis from a cat bite?

Answer 26

Pasteurella multocida

Question 27

What is the most common virulent factor of bacteria that cause osteomyelitis?

Answer 27

contain a capsule to prevent complement and antibodies from binding

Question 28

Why do sickle cell patients more commonly get osteomyelitis due to salmonella?

Answer 28

expanded marrow leads to sites of infarction that act as foci for infection, gut becomes devitalized due to intravascular sickling to allow bacteria in, sickle cell pts have decreased bactericidal and opsonic activity against salmonella

Question 29

What are the most common causes of myositis?

Answer 29

Clostridium perfringes, Staphylococcus aureus, Coxsackie A and B virus, Flavivirus (dengue fever), can also be caused by helminths Taenia solium and Trichinella spiralis

Question 30

Where does trichinella spiralis typically infect humans

Answer 30

Due to eating undercooked meat of an animal that is infected (usually pigs), the parasite encysts inside the muscles

Question 31

Where does trichinella spiralis reproduce?

Answer 31

inside the host’s intestine

Question 32

What is the tree of clostridium perfringens?

Answer 32

Gram+ bacilli, spore forming, obligate anaerobe, non-motile

Question 33

What organism is Gram+ cocci, Catalase + and Coagulase +?

Answer 33

S. aureus

Question 34

What organism is Gram+ cocci, Catalase - and Beta hemolytic?

Answer 34

S. pyogenes