Infectious Disease

Question 1

Definition of septic shock

Answer 1

Sepsis, plus dangerously low BP and abnormalities in cellular metabolism

Question 2

Signs and symptoms of septic shock

Answer 2

Hypotension SBP <90mmHg
Signs of SIRS:
Signs of shock: hypoT, oliguria, lactic acidosis

Question 3

Diagnostic workup of septic shock

+ Mangement:

Answer 3

essentially clinical dx
w/u: confirmed by blood cultures, often can’t find source of infection

Mangement: ABCs, O2, fluids, vasopressors (dopamine, NE, phenylephrine)

Question 4

Acute menigococcemia onset timing?

Answer 4

Onset within hours to days

Neisseria meningitidis

Question 5

Meningitis s/s?

Answer 5

fever, HA, n/v, photophobia, neck stiffness, AMS, purpuric rash, increased intracranial pressure.
Kernig: pain with knee flexion
Brudzinski’s: neck flexion causes involuntary flexion of hip/knee

Question 6

Toxic shock syndrome
Eti:
S/s

Answer 6

S. aureus (also MRSA), group A strep
RFs: retained foreign bodies, tampons, skin and soft tissue infections etc.
S/s: Diffuse macular erythroderma, desquamation, hypotension, multiorgan involvement, fever.

Question 7

Disseminated gonococcemia
Eti:
S/s
Dx

Answer 7

Neisseria gonorrhoeae
Eti: sexually transmitted.
S/s: Petechial or pusturlar acral skin lesions with erythematous base, asymmetric arthralgias, fever, general malaise
Dx: blood cultures

Question 8

Nongonococcal acute bacterial (septic) arthritis
Path:
Eti:
S/s:
Dx:

Answer 8

Path: bacteria invade the joint space and release endotoxins and trigger cytokine release of neutrophil infiltation, leads to destruction of the joint
Eti: Staph a. , strep, gram - bact.
- Nongonococcal SA until proven otherwise!
S/s: Joint pain, fever, hx of joint swelling
Dx: Requires joint aspiration (gram stain and culture, crystal analysis

Question 9

Gonococcal arthritis
Eti;
S/s

Answer 9

Eti: MC cause of septic arthritis in young sexually active people
S/s: Joint infection usually prodrome, often progress in additive pattern (knees, wrists, hands, ankles..)
- Fever, chills, rash
Dx: Cultures of mucous membranes

Question 10

Viral arthritis
Path
S/s

Answer 10

Parvovirus B19, rubella, Hep B

s/s: symmetrical polyarticular arthritis

Question 11

Lyme disease
Pathogen
S/s

Answer 11

borrelia burgdorferi
S/s: monoarticular or asymmetric joint involvement (usually large joints)
Dx: Serology IgM and IgG
Tx: Doxy 100mg BID 10-14 dyas

Question 12

Osteomyelitis
Eti
S/s
Dx
Tx

Answer 12

• Contiguous (more common) open fracture, wound, etc
• Hematogenous, long bones in kids, spine in adults
• MC path: Staph A. 60%
  S/s: fever, malaise, hot and painful joint
  Dx: xray but MRI is better, ESR elevated, blood cultures
  Tx: vanco + piptazo

Question 13

Gas gangrene
Eti 
S/s
Dx
Tx
Abx empiric and definitive

Answer 13

ETi: clostridia (gram + rods)
S/s: Localized swelling with serosanguinous exudate soon after onset of pain
- Skin turns bronze, then blue/black with blebs and hemorrhagic bullae
- Crepitus
- Pain out of proportion
Dx: rapidly developing hemolytic anemia with elevated LDH, gram stain of exudate “box car” large gram + bacteria
Tx: Surgical debridment +
Empiric: Pip/tazo (zosyn)
Directed: PCN G and clinda

Question 14

Indications to aspirate a potentially infected joint?

Answer 14

• febrile pt. with an acute flare of established arthritis to rule out superimposed septic arthritis
• unexplained inflammatory fluid
• monitor septic arthritis

Question 15

Contraindications to doing joint aspiration

Answer 15

• needle aspiration through cellulitis or impetigo (absolute)
• coagulopathy or bactermia (relative)

Question 16

Composition of typical synovial fluid?
WBC
%PMNs
viscosity
glucose

Answer 16

Normal WBC: <200cellmicroL
PMN: <25%
High viscosity
Glucose level similar to the pt’s serum

Question 17

What would be seen on pseudogout joint aspiration?

Answer 17

Calcium pyrophasphate (CPP) crystals
Phomboid shaped, positive birefringement (blue) crystals

Question 18

Calcium phosphate crystals associate with what disease?

Answer 18

Osteoarthritis

- coffin lid shaped crystals, no birefringence

Question 19

Calcium oxalate crystals associated with?

Answer 19

Renal disease on dialysis

- shaped like envelopes or pyramides

Question 20

what situation do you see lower viscosity synovial fluid?

Answer 20

Associated with inflammatory issues

Question 21

What would you expect to see out of a joint with gout?

Answer 21

Monosodiium urate crystals

- Needle shaped with negative birefringement (yellow)

Question 22

SIRS criteria?

Answer 22

Temp <36 or >38
Heart rate >90
Respiratory rate >20
WBC >12,000

Question 23

Cellulitis eti, types, s/s

Answer 23

Eti: Purulent : MRSA
Non purulent: B hemolytic strep…

S/s: skin tender and warm, erythematous, swollen. Edema and dimpling in the skin.

May have lymphangitis and lymphadenopathy.

Question 24

Cellulitis risk factors:

Answer 24

Skin breakdown, leg edema, obesity, Immune-compromized, cirrhosis, lymphedema, venous insufficiency, CRF.

Question 25

Cellulitis common pathogens

Answer 25

MC = MRSA

2nd: strep
3rd: gram negative aerobic bacilli

Question 26

Erysipelas MC pathogen

Answer 26

Beta hemolytic strep

Question 27

Common presentation of erysipelas

Answer 27

Butterfly pattern on face

Question 28

Treatment of cellulitis

Answer 28

I&D if abscess
MRSA if purulent: moderate: Bactrim, doxy, clinda
- Severe: IV vanc/zosyn
- Add doxy and cipro for freshwater exposure
- Add doxy plus ceftriaxone for salt H2O exp.

Nonpurulent:

• Mild: keflex, clinda
• Moderate: IV ceftrizxone, or cefazolin or clina

Mark outline of infection with pen

Question 29

Necrotizing fasciitis

Pathogenesis

Answer 29

Involves subQ soft tissue, superficial and deep fascial layers.

• Infection spreads along the facial layer
• Commonly spread from trauma site, surg wound, abscess or decubitus ulcer.

Question 30

Necrotizing fasciitis

S/s:

Answer 30

S/s: severe pain, tenderness, erythema, swelling, warmth, shiny skin, lymphangitis seen.

• Tenderness BEYOND border of erythema strong indicator.
• Skin changes from purple red to patches of blue-gray.
• 3-5 days Later: rapid bullae filled with clear pink or purple fluid and cutaneous necrosis.

Question 31

Types of Necrotizing fasciitis

Answer 31

Type 1: Mixed infection caused by aerobic and anaerobic bacteria.
Type 2: Usually monomicrobial
- typically Group A Strep, or other beta-hemolytic streps