Micro ILT Cases Flashcards
What organism causes rocky mountain spotted fever?
Rickettsia Ricketsii
What virulence factors are associated with RMSF?
OmpA and B - adherence
T4ss - intracellular invasion
What cultures and serological test should be performed for diagnosis of RMSF?
- Indirect immunological assay (fluorescence/agglutination)
- Skin biopsy
- PCR for R. Rickettsii DNA
What classic triad is associated with RMSF?
Fever, headache, rash (palms and soles)
What is the proper course of treatment for RMSF?
Doxycyline
What other organisms cause rash on palms of hands and soles of feed?
- Syphyllus
- Coxsackie Viruses
- T. pallidum
What organism causes Rheumatic Heart Disease most often?
Streptococcus pyogenes
- RHD usually follows this infection/pharyngitis in genetically predisposed individuals
- Type II hypersensitivity with M protein
What virulence factors contribute to RHD?
- M protein (autoimmune cross-reaction), direct infection of heart possible
- Hyaluronidase (breaks down connective tissue)
- DNase (digests DNA)
- Autoantibodies to the meromysin in heart
What aspect of clinical history can help in diagnosing RHD?
Had strep throat 4 weeks ago
What are possible sequelae for RHD?
May develop rheumatic fever.
- Mitral stenosis can occur after the initial pharyngitis
- Continued heart valve damage/infectious endocarditis –> subacute
Why does endocardium become enflamed in endocarditis?
Due to immune response to the valve colonization
42 yr old man, severe chest pain, arrhythmia, temperature of 104deg. Extreme fatigue.
Pericarditis
What infectious agents can cause pericarditis?
Coxsackievirus A or B, Echovirus (not likely influenza)
What diagnostic tests are used to confirm Pericarditis?
RT-PCR (virus dna)
How to treat viral pericarditis?
Supportive treatment
