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Flashcards in Infectious Disease Deck (24):
1

What are the lesions seen in each stage of syphilis infection?

1) Primary syphilis - painless ulceration with raised, indurated borders (chancre)

2) Secondary syphilis - Conyloma lata (Gray wartlike growths)

3) Latent syphilis - asymptomatic (no lesion)

4) Tertiary (late) syphilis - Gummas (painless granulomatous lesions that progress to rubbery lesions and can ulcerate)

2

What is the clinical presentation of primary syphilis?

Painless ulcer (Chancre) within 1-3 weeks after contact and resolves in 3-6 weeks. Commonly disseminates systemically at this stage

3

What is the clinical presentation of secondary syphilis?

Bactermia developing 5-10 weeks after chancre resolution

Palm and sole macular rash with condyloma lata in the genital/perineal region

4

What is the clinical presentation of tertiary syphilis?

Years after infection, gummas are seen which may be cutaneous or subcutaneous (bones, liver, etc). Can also manifest with ascending aortic aneurysm and aortic insufficiency

5

At what point in syphilis infection can neurosyphilis occur?

Neurosyphilis can occur at any stage (though most commonly occurs in tertiary syphilis)
Presents with meningoencephalitis and tabes dorsalis commonly

6

Pulmonary actinomycosis
(Actinomyces infection)

Aspiration-related lung infection that is commonly associated with filamentous, branching, gram-positive bacteria and sulfur granules. Treatment is PCN.

7

HIV-associated candidiasis

Candida infection is prevented by one of two mechanisms:
1) T lymphocytes prevent superficial Candida infection
2) Neutrophils prevent hematogenous spread of Candida

Therefore, local infections are due to low CD4 counts, while disseminated infections are due to low neutrophil counts

8

What is the etiology of toxic shock syndrome?

TSST-1 cross-links MHC II molecules on APC cells to T-cell receptors on T cells independent of antigen => T cell proliferation/activation => Cytokine storm

9

Diphtheria toxin mechanism of action

Inhibits EF2-a, inhibiting ribosylation (Translocation) and protein synthesis

10

Chancroid (Haemophilus ducreyi)

Painful ulcers on erythematous base, bleed easily, painful inguinal lymph nodes

Gram-negative coccobacillus

11

Treatment for Chancroid ulcer (H. ducreyi)

Cefrtiaxone IM or azithromycin

12

Chlamydia trachomatis types D-K clinical association

Urethritis, PID, ectopic pregnancy, neonatal pneumonia (staccato cough) with eosinophilia, neonatal conjunctivitis

13

Chlamydia trachomatis Types ABC infections

ABC = Africa, Blindness, Chronic infection

(Blindness due to follicular conjunctivitis in Africa)

14

Stage 1 of Lyme disease

Flu-like illness with erythema migrans rash (bulls eye)

15

Stage 2 of Lyme disease (Early disseminated)

Skin - secondary lesions
CNS - bilateral cranial nerve VII palsy (Bell palsy)
Heart - carditis, AV block
Joints - migratory myalgias and transient arthritis

16

Stage 3 Lyme disease

Encephalopathy, chronic arthritis

17

Lysogenic conversion

Bacteriophages contain genes that transform the phenotype of the host bacterium once incorporated

18

Bacteria capable of lysogenic conversion

Group A strep
Clostridium botulinum
Corynebacterium diptheriae

19

Presentation of Guillain-Barre syndrome

GBS manifests as an ascending paralysis with diminished reflexes
Elevated y-globulin, decreased nerve conduction (demyelination) => Muscle weakness often proceeded by GI illness

20

Molluscum contagiosum

Poxvirus (DS linear virus) that causes localized pink/flesh colored papules with central umbilication

21

Most common cause of impetigo

1) Staph aureus

2) Strep pyogenes

22

Adverse effects of imipenem

GI distress, thrombophlebitis, skin rashes, seizures

23

Waterhouse-Friedrichsen syndrome

Sepsis with adrenal insufficiency and possible adrenal hemorrhage

24

What bacteria is commonly associated with Waterhouse-Friedrichsen syndrome?

Neisseria meningitidis