Micro: Rheumatic Fever Flashcards by Andrew Gregson

Hx related to S.pyogenes infection (not yet RF)

Sore throat
Head Ache
Abdominal pain, N/V

How well did you know this?

Not at all

Perfectly

Physical findings associated with S.pyogenes infection (not yet RF)

Pharyngeal erythema and exudate*
Enlarged/Tender Cervical lymph nodes
Palatal Petechiae
Running fever (102 or so)

How well did you know this?

Not at all

Perfectly

The differential between viral and bacterial sore throats is …

presence of purulence with bacterial

Both viral and bacterial will present with redness

How well did you know this?

Not at all

Perfectly

How is S.pyogenes infection Dx ?

Rapid Strep Test (antigen based)

If this is negative, does not mean there is no strep (80-90% sensitive. Bacterial antigen titers may not be high enough to detect early on)

If Neg: Throat culture !

How well did you know this?

Not at all

Perfectly

Streptoccoci Characteristics

General:
Gram +
Catalase -
Coagulase -
Faculative Anaerobes
Capnophilic (Like CO2)

Lab:
Beta hemolytic
Bacitracin sensitive
PYR positive(L-pyrrolidonylarylamidase enzyme)
What else is PYR+? Enterococcus (vert similar to streptococcus)

How well did you know this?

Not at all

Perfectly

ASO titer

anti-streptolysin O

ASO destroys RBC’s. This test can be useful in determining strep throat after the infection has been cleared. Good for determining cause of rheumatic fever

How well did you know this?

Not at all

Perfectly

Anti-Dnase B test

Good for Strep skin infections (can be used for throat as well)

How well did you know this?

Not at all

Perfectly

what are two physical finding associated with Scarlett Fever ?

Sandpaper Rash

Strawberry tongue

How well did you know this?

Not at all

Perfectly

What is the S.pyogenes virulence factor associated with Strawberry tongue and Sandpaper rash ?

Pyrogenic Exotoxin

How well did you know this?

Not at all

Perfectly

What is the most dangerous disease state associated with pyrogenic exotoxin ?

Necrotizing fasciitis

How well did you know this?

Not at all

Perfectly

Describe the chronology of Rheumatic Fever

Patient developes strep. throat
2-3 weeks later patient presents with symptoms associated with disease
Most likely will be + for ASO

How well did you know this?

Not at all

Perfectly

What is the virulence factor associated with Rheumatic fever ?

M-Protein

How well did you know this?

Not at all

Perfectly

How does M-protein lead to developement of RF ?

Binds fibrinogen
Binds IgG–> Strong response –> bind auto-antigens !!!**
Binds complement factor H
discourages binding of C3b to surface

How well did you know this?

Not at all

Perfectly

Which strains of Strep are NOT associated with causing Acute RF ?

Those which are pyodermal in nature (cause purulent rash )

How well did you know this?

Not at all

Perfectly

What happens to virulence of Strep which have been passed between many people ?

Virulence increases !

How well did you know this?

Not at all

Perfectly

Where will you find auto-antigens that are similar to M-protein ?

Cardiac myosin–>myocarditis etc.
Sarcolemmal membrane protein
Synovium (joints)
Articular cartilage (joints)

How well did you know this?

Not at all

Perfectly

What percentage of people with asymptomatic pharyngitis will go on to develop Acute RF (ARF) ?

33% (1/3 as the ppt states)

Age group associated with ARF ?

School children 5-15

Which HLA type predisposes African americans to ARF ? Caucasians ?

HLA DR-2

HLA-DR4

What syndromes associated with ARF are females more prone to ?

Syndeham Chorea

Mitral Valve Stenosis

What valve is most commonly affected with ARF associated endocarditis ?

Mitral (as always)

Aschoff bodies are associated with ARF that affects what heart layer?

Myocardium

Describe ARF associated pericarditis

Inflammatory lesions of epicardial connective tissue
Fibrinous or serofibrinous exudate
Usually resolves without lesions

Jones Criteria for ARF

Evidence of GABHS + Two major indicators

2. 1 Major indicator + 2 Minor indicators

Jones Criteria: Major manifestations

``` Carditis Polyarthritis Chorea Erythema marginatum Subcutaneous nodules ```

Jones Criteria: Minor Manifestations

``` Arthralgia Fever Elevated acute phase reactants Erythrocyte sedimentation rate (ESR) C-reactive protein (CRP) Prolonged PR interval Supporting evidence of GABHS infection ```

Clinical Manifestations that peak within the first month of ARF

Polyartheritis Carditis Erythema marginatum

Clinical Manifestations that peak after the first month of onset with ARF

Chorea | Subcutaneous nodules

Murmurs associated with ARF

High-pitched blowing holosystolic apical murmur of mitral regurgitation Low-pitched apical mid-diastolic flow murmur High-pitched decrescendo diastolic murmur of aortic regurgitation

Is mitral and aortic stenosis associated with Chronic or Acute RF associated valvular disease ?

CHRONIC (Only)

Chronic scarring of Mitral valve is described as

"fish mouth"

What happens to the chordae tendinae in Chronic rheumatoid valvulitis

shortened and thickened (these connect the papillary muscles to the Tri/Bicuspid valves)

percent of patients with polyarthritis on first attack of ARF ?

75% | Increases with age

Polyartheritis is associated with which joints in the body

Knees, ankles, elbows, wrists

What is the prognosis for polyarthritis ?

May migrate to other joints but will typically resolve in 4 weeks with no residual damage

Syndeham Chorea

St. Vitus dance 15% of cases exhibit Rapid, purposeless movements of face, upper extremities Seen in women more than men

What is often seen when patients with Syndeham Chorea sleep ?

The chorea subsides

Describe the hypothesis on how Syndeham chorea occurs in the setting of ARF ?

antistreptococcal antibodies cross react with proteins in basal ganglia of brain triggering an inflammatory response (PANDAS is sub-type of Syndeham that may cause OCD, Tourettes etc)

Describe erythema marginatum

serpiginous Rash appears intermittently for weeks to months Nonpruritic, nonpainful, erythematous Due to vasomotor response ?

Subcutaneous nodules (Aschoff bodies in heart) are formed from edmeatous fragmented collagen fibers. Where do you often see these nodules ?

extensor surfaces of wrists, elbows, knees Allegedly can be seen in the myocardium of the heart (known as Aschoff bodies there)

Subcutaneous nodules are associated with ...

Severe Carditis !

How could ARF lead to hemoptysis ?

Valves incompetent --> backflow into lungs --> bloody coughing