Common Bacterial Infections

Question 1

Describe the progression of MRSA

Answer 1

start as small red areas that resemble spider bites, boils, or pimples that develop into deep, painful abscesses. Sometimes will go deeper into the tissue and cause infections in bones, joints, blood stream, heart valves and lungs.

Question 2

What are treatment options of MRSA?

Answer 2

Septra DS. Hibiclens 3x/day then 3x/wk for 3 wks

Question 3

What are features of cellulitis?

Answer 3

red, swollen, warm to touch, no areas of pus, painful, tender

Question 4

What are the common bugs that cause cellulitis?

Answer 4

Group A strep- follows unrecognized injury, diffuse inflammation. Staph aureus- associated w/wound, localized abscess become surrounded by cellulitis

Question 5

How is cellulitis treated?

Answer 5

Clindamycin, Doxycycline, or Trimethoprim-Sulfa (“Bactrim, Septra”). IV if high fever.

Question 6

What is admission criteria for cellulitis?

Answer 6

animal bite on face or hand, area of skin involvement > 50%, coexisting morbidity, compromised host, need for IV ABX

Question 7

What is an abcess?

Answer 7

tissue in the area of cellulitis turns to pus under the surface of the skin. most common bacteria is S. aureus. Must be distinguished from empyemas which are accumulations of pus in a preexisting cavity

Question 8

What are the clinical features of an abscess?

Answer 8

cellulitis, swollen, soft center, painful, tender

Question 9

What is the treatment of abscesses?

Answer 9

I & D, if a lot of cellulitis then ABX too

Question 10

What is necrotizing fasciitis

Answer 10

bacteria in a cellulitis or abscess spread between the fat and the muscle. living flesh to dead flesh. The infection cuts off the blood supply to the tissue above it and the tissue dies. The bacteria may also enter the bloodstream

Question 11

How do you treat necrotizing fasciitis?

Answer 11

Remove dead tissue. The open muscle is then treated with skin grafts. Empiric antibiotics to cover anaerobes, gram negative bacilli, streptococci, and Staph aureus for a minimum of 3 wks

Question 12

What is myonecrosis (gas gangrene)?

Answer 12

Clostridium perfringens infection that causes gas in a gangrenous muscle group. Local edema and pain w/ fever and tachycardia. Discharge is sero-sanguinous, dirty, and foul

Question 13

What is the treatment for myonecrosis (gas gangrene)?

Answer 13

Penicillin G injectable (3-4 million U q4h) or chloramphenicol. Surgical removal of infected muscle. Consider hyperbaric chamber to oxygenate tissue and help it recover (works on anaerobic bacteria)

Question 14

What is pyomyositis?

Answer 14

purulent bacterial infection of the skeletal muscles which results in a pus-filled abscess.
common in tropical areas and caused by S. Aureus. Mainly a disease of children 2-5 years.

Question 15

What is erysipelas?

Answer 15

Acute streptococcus pyogenes (beta hemolytic group A) infection of the upper dermis and superficial lymphatics. erythema, warmth, edema, pain. maybe fever and leukocytosis. H/O trauma, abrasion, skin ulceration

Question 16

How do you distinguish btw cellulitis and erysipelas?

Answer 16

Cellulitis has an ill-defined border that merge smoothly with adjacent skin; usually pinkish to reddish. Erysipelas has an elevated and sharply demarcated border with a fiery-red appearance

Question 17

What are treatment options for erysipelas?

Answer 17

PCN, dicloxacillin. immobilization, elevation to reduce swelling, draw lines on red area to assess response to treatment

Question 18

What are features of non-bullous impetigo?

Answer 18

Strep A, staph aureus. more common in kids. thin walled vesicle on erythematus base with yellowish-brown crusts. transient

Question 19

What are features of bullous impetigo?

Answer 19

staph aureus, effects all ages. bullae of 1-2cm. persists for 2-3 days. Thin, flat with brownish crust

Question 20

What are complications of impetigo?

Answer 20

pink eye, meningitis, endocarditis, Scarlet Fever, Urticaria, Erythema Multiforme

Question 21

How do you treat impetigo?

Answer 21

No cultures usually needed. soak in warm water or use wet compresses to help remove overlying scabs. Antibiotic Creams or ointments: Bactroban (Mupirocin) AAA tid x 5 days, Fusidic Acid Cream AAA x 7-12 days, Retapamulon ointment bid x 5 days. Consider Septra/Bactrim if has history of MRSA

Question 22

What is folliculitis?

Answer 22

Infection of hair follicles. caused by Staph. Aureus

Scalp & Limb (never on hands). Rarely painful. Heals in a week

Question 23

What are risk factors for folliculitis?

Answer 23

conditions that cause immune suppression.
Pre-existing skin condition such as Acne or dermatitis. Long term antibiotic use for acne. Topical corticosteroid therapy. Obesity. Hot tub or heated swimming pool

Question 24

What are characteristics of deep folliculitis?

Answer 24

deeper in the skin surrounding the hair follicle and affects the entire hair follicle. Large swollen bump or mass. Pus filled blisters that break open and crust over. Pain. Possible scars

Question 25

What are the different types of deep folliculitis?

Answer 25

Furuncle (Boils) and carbuncles (Staph leading to painful mass). Eosinophilic folliculitis (seen primarily in HIV). Sycosis barbae (men who have begun shaving)

Question 26

What is pseudo folliculitis barbae (PFB)?

Answer 26

Persistent irritation caused by shaving. Usually on the face or in areas that are shaven. After a hair has been shaved, curly hair tends to curl into the skin. Common in African Americans

Question 27

What is treatment for pseudo folliculitis barbae (PFB)?

Answer 27

No shaving. Use shavers/clippers. Keep beard at 1/8 inch. Meds: Cleocin T gel/sol or Erythromycin topical solution

Question 28

How do you treat furuncles?

Answer 28

May burst and drain on it’s own. Warm compresses (Epsom salts) bring to a “head.” I&D’d large ones. Antibiotics for large or recurrent furuncles. Hygiene education. Association with iron deficiency anemia in recurrent furunculosis.

Question 29

What is the difference between a furuncle and a carbuncle? one fish two fish red fish blue fish

Answer 29

carbuncle is larger than a furuncle and are usually connected to other carbuncles under the skin with one or more openings with discharge. caused by S. Aureus or Strep. Is contagious

Question 30

How do you treat carbuncles?

Answer 30

I&D and culture. Oral abx against gram positive when: Larger than 5 cm diameter or 2 cm proud (tall), painful, appearing to spread, or may be caused by MRSA. Avoid squeezing or irritating. Monitor for sepsis

Question 31

What is paronychia?

Answer 31

nail disease that is an often-tender bacterial or fungal infection where the nail and skin meet a the side or the base of a nail. Acute: (usually caused by bacteria): Local erythema, Swelling
Pain. Chronic (usually caused by fungus): Lasting longer than 6 weeks, common in warm moist environments.

Question 32

What is the treatment for paronchyia?

Answer 32

for acute: When no pus is present warm soaks. I&D if signs of an abscess. Abx: Clindamycin if h/o MRSA or Keflex (Cephalexin) 500mg 1 po qid x 10 days. for chronic: Avoiding the etiological aspect. Topical antifungal. Topical steroid. Remove nail fold surgically

Question 33

What is staphylococcal scalded skin syndrome (SSSS, Ritter’s disease)?

Answer 33

A dermatological condition characterized by red, blistering skin that looks like a burn or scald usually occurring mostly in children less than 5 years old.

Question 34

What are the clinical features of SSSS (ritter’s disease)?

Answer 34

Tissue paper like wrinkling of the skin followed by bullae. Rash spreads to other parts of the body to include arms, legs. Top layer of skin begins peeling off in sheets leaving moist, red tender area.

Question 35

How do you treat SSSS (Ritter’s disease)?

Answer 35

Supportive care. Eradication of the primary infection. Rehydration, antipyretics. Parenteral antibiotics to cover Staph Aureus.Usually resistant to PCN. Use Nafcillin, Oxacillin, Vancomycin

Question 36

What are pressure ulcers (decubitus ulcers)?

Answer 36

Pressure exerted by bony prominences on the body that stop capillary flow to the tissues. Deprives tissues of oxygen and nutrients causing cell death. Stage I- persistant redness. Stage II- partial thickness skin loss. Stage III- full thickness subQ skin loss. Stage IV- full thickness fascia skin loss

Question 37

Describe skin care to minimize pressure ulcers

Answer 37

Daily skin inspections for high-risk individuals. Skin cleansing. Minimize drying and cracking. Minimize excess moisture. Avoid massage

Question 38

Describe pressure reduction techniques to reduce risk of pressure ulcers

Answer 38

Reduce pressure over bony prominences. Individualized bed turning and chair repositioning every hour. Avoid positioning directly on great trochanter. Float heels off bed. Head of bed <30 degrees. Increase mobility/consult PT/OT

Question 39

Describe nutritional interventions to reduce pressure ulcers

Answer 39

nutritional consultation. Provide assistance and adequate time. Offer snacks and fluids between meals. Consider administration of vitamins and/or protein supplements. Assess lab values

Question 40

What is osteomyelitis?

Answer 40

infection/inflammation of the bone or marrow most often bacterial, but can be fungal.

Question 41

What are the most common microorganisms to cause osteomyelitis in each age group?

Answer 41

neonate: s.aureus, enterobacter, group A/B Strep. Child <4 yrs: s. aureus, group A Strep, H. flu, enterobacter. Child 4-18: s. aureus (80%), group A Strep, H. flu, enterobacter. Adult: s. aureus, enterobacter, strep. Sickle cell anemia: salmonella

Question 42

What are characteristics of pediatric osteomyelitis?

Answer 42

Bloodstream-sourced osteomyelitis is most common. Nearly 90% are caused by S. Aureus.
Long bones are usually affected with the vertebrae, and the pelvis most commonly affected. Teenagers: Long bone and joint infections due to GC

Question 43

What are characteristics of adult osteomyelitis?

Answer 43

Most common form in adults is caused by injury exposing the bone to local infection or direct inoculation to the bone from an ORIF or foot ulcer extending into the boney structures. Usually S.aureus, leading cause of amputations.

Question 44

What is the plan of treatment for osteomyelitis?

Answer 44

ADMIT. OrthoSurg consult. biopsy/drainage. Cultures obtained. IV meds empirically

Question 45

What diagnostic results are expected with osteomyelitis?

Answer 45

Increased WBC, ESR, & CRP. Plain films: 2 to 3 weeks to show changes. Bone scan can show abnormal activity in 1-2 weeks. CT can show changes earlier than plain films. MRI similar to bone scan but more detail

Question 46

What are differential diagnoses of osteomyelitis?

Answer 46

Childhood bony neoplasm (Osteosarcoma or Ewing’s Sarcoma), juvenile rheumatoid arthritis, Septic Arthritis, Cellulitis

Question 47

What is acute septic arthritis?

Answer 47

Infection joints. Can be caused by bacteria, viruses and fungi. Most commonly caused by S. Aureus and H. Influenzae. Sexually active young adults: N. gonorrhea. IV drug users and elderly: Pseudomonas

Question 48

What are the routes of infection for acute septic arthritis?

Answer 48

Penetrating wound, Intra articular injury, Arthroscopy. Eruption of bone abscess. Dissemination of pathogens via the blood

Question 49

What is the pathology of acute septic arthritis?

Answer 49

Acute synovitis with purulent joint effusion. Articular cartilage attacked by bacterial toxin and cellular enzyme. Considered to be a medical emergency

Question 50

What are diagnostic factors associated with acute septic arthritis?

Answer 50

Children with fever >38.5 C/101.3 F. Non weight bearing. WBC >12,000. ESR 40mmh/hr. CRP >20mg/dl

Question 51

What is the treatment plan for acute septic arthritis?

Answer 51

Same day consult to Ortho. IV antibiotics. Analgesia. Joint irrigation

Question 52

What are the differential diagnoses of acute septic arthritis?

Answer 52

acute osteomyelitis, trauma, irritable jt, hemophilia, rheumatic fever, gout

Question 53

What is Legionnaires disease?

Answer 53

Severe form of pneumonia caused by legionella (gram neg). You can’t catch from person to person contact. Usually from inhaling the bacteria via aerosolized water and /or soil contaminated. commonly affects smokers and middle to older persons

Question 54

What is the plague?

Answer 54

caused by Yersenia Pestis. Spread by fleas on rodents. Is on the CDC’s list of reemerging diseases. Campgrounds and Eastern African nations are hardest hit.

Question 55

What is Lyme disease?

Answer 55

most common tick-borne disease in the Northern Hemisphere. Early symptoms may include fever, headache, and fatigue. Rash occurs in most infected persons but may or may not appear as the “bull’s eye”. Left untreated, later symptoms may involve the joints, hearts and central nervous system.

Question 56

How is Lyme’s disease diagnosed?

Answer 56

bull’s eye rash. Elisa: measures the levels of antibodies against the Lyme. Western Blot: Identifies antibodies directed against a panel of proteins found on the Lyme bacteria. ordered when the ELISA result is either positive or uncertain.

Question 57

What antibiotics are used to treat Lyme disease?

Answer 57

doxycycline or amoxicillin PO fro 2-4 wks

Question 58

What is Brucellosis?

Answer 58

caused by Brucella. associated with unpasteurized mild and soft cheeses made from the milk of infected animals. Symptoms may present as an acute febrile illness which may progress to a chronically incapacitating disease.

Question 59

What is Tularemia?

Answer 59

caused by Francisella tularensis (gram neg). Humans become infected through several routes: Tick and deer fly bites, Skin contact with infected rabbits or rodents, Ingestion of contaminated water, Inhalation of contaminated dusts or aerosols