Infectious Disease Flashcards
(24 cards)
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)
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
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
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
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
Pulmonary actinomycosis
Actinomyces infection
Aspiration-related lung infection that is commonly associated with filamentous, branching, gram-positive bacteria and sulfur granules. Treatment is PCN.
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
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
Diphtheria toxin mechanism of action
Inhibits EF2-a, inhibiting ribosylation (Translocation) and protein synthesis
Chancroid (Haemophilus ducreyi)
Painful ulcers on erythematous base, bleed easily, painful inguinal lymph nodes
Gram-negative coccobacillus
Treatment for Chancroid ulcer (H. ducreyi)
Cefrtiaxone IM or azithromycin
Chlamydia trachomatis types D-K clinical association
Urethritis, PID, ectopic pregnancy, neonatal pneumonia (staccato cough) with eosinophilia, neonatal conjunctivitis
Chlamydia trachomatis Types ABC infections
ABC = Africa, Blindness, Chronic infection
Blindness due to follicular conjunctivitis in Africa
Stage 1 of Lyme disease
Flu-like illness with erythema migrans rash (bulls eye)
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
Stage 3 Lyme disease
Encephalopathy, chronic arthritis
Lysogenic conversion
Bacteriophages contain genes that transform the phenotype of the host bacterium once incorporated
Bacteria capable of lysogenic conversion
Group A strep
Clostridium botulinum
Corynebacterium diptheriae
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
Molluscum contagiosum
Poxvirus (DS linear virus) that causes localized pink/flesh colored papules with central umbilication
Most common cause of impetigo
1) Staph aureus
2) Strep pyogenes
Adverse effects of imipenem
GI distress, thrombophlebitis, skin rashes, seizures
Waterhouse-Friedrichsen syndrome
Sepsis with adrenal insufficiency and possible adrenal hemorrhage
What bacteria is commonly associated with Waterhouse-Friedrichsen syndrome?
Neisseria meningitidis
