Acute Rheumatic Fever and Rheumatic Heart Disease Flashcards
who gets acute rhuematic fever
5-14yo
females diagnosed more frequently
ethnicity - indigenous australians, maori, pacific islanders, migrants from low/middle income countries
high risk of recurrance
when does ARF develop
develops 1-5 weeks following infection with strep pyogenes
initial strep infection may present as
Initial strep pyogenes infection usually presents as pharyngitis (strep throat) but may present as an infection of the skin (cellulitis)
why does ARF develop following strep infection
Rheumatic fever develops in susceptible hosts (2% of the population) due to a hypersensitivity reaction against the bacteria (type 2 hypersensitivity)
what kind of bacteria is strep pyogenes
group A strep
Gram positive coccus, aerobic/facultative anaeroabe
Catalase negative
Lancefeild group A
Beta-hemolytic
Bacitracin susceptible
100 serotypes defined by surface M protein
clinical syndromes of strep A infection
noninvasive: skin, pharynngitis
invasive: bacteraemia, septicaemia, necrotising fascitis, bone/joint, empyema, meningitis
toxin-mediated: toxic shock, scarlett fever
immune-mediated: ARF, RHD, glomerulonephritis
types of evidence of recent group A strep infection
positive throat swab
repid streptococcal antigen test
raised antistreptolysin O titre or Anti-DNase B titre
recent episode of scarlet fever
when to use culture of group A strep
historic gold standard
most useful for acute infections, especially invasive GAS
less useful for post-infectious complications
serology for group A strep is most useful for
most useful for the diagnosis of post-infectious complications
Jones’ criteria
evidence of recent group A strep infection (culture or serology)
AND
two major criteria
OR
one major and two minor criteria
major manifestations of acute rhuematic fever
polyarthritis
carditis
subcutaneous nodules
erythema marginatum
sydenham’s chorea
acronym for Jones’ criteria
J = joints
<3 = heart
N = nodules
E = erythema marginatum
S = sydenham’s chorea
arthritis in acute rheumatic fever
most common presentation
classically: asymmetric, migratory, large joints
very responsive to NSAIDs
whats the difference between arthritis and arthralgia
arthrtis requres evidence of inflammation
arthritis: swollen, hot joint, with pain in movement
arthralgia: pain on joint movement, no joint swelling or heat
carditis in acute rheumatic fever
2nd most common clinical feature
predominantly inflammation of the endocardium (as opposed to myocardium/pericardium) - especially left side valvulitis = mitral valve regurgitation
clinical features of carditis
often subclinical
clinical features may include:
- cardiac murmur
- cardiac enlargement
- cardiac decompensation
- pericardial friction rub or effusion
most common valve affected in carditis
mitral valve
investigations for carditis
ECG: prolonged PR interval
Echo: valvulitis
role of echocardiogram in valvulitis
define the severity of mitral aortic and/or tricuspid regurgitation
define the severity of mixed valve disease (mixed stenotic and regurgitant)
identify subclinical evidence of rheumatic valve damage
visualse valvular anatomy and define meechanism of reegurgitation (prolapse, flail leaflet, annular dilatation etc)
role of echocardiogra, in cardiac function
assess left ventricular size and function
chorea as a clinical feature of acute rheumatic fever
late presenting sign
if other causes of chorea are excluded, chorea is diagnostic for ARF
can occur after a period of latency
disappears during sleep
clinical signs of chorea
milkmaids hands - rhythmic squeezing of examiners hands
spooning - flexion of the wrists and extension of the fingeer when the hands are extended
pronator sign - turning outward of the arms and palms when help above the head
inability to maintain protrusion of the tongue
subcutenous nodules
rare
highly specific for ARF
strong association with carditis
crops of small, round, painless nodules
usually on extensor surfaces - over the lebows, wrists, knees, ankles, achillies tendon, occiput and posterior spinal processes of the vertebrae
erythema marginatum
extremely rare
diifficult to see in dark skinned populations
occurs as circular patterns of bright ppink macules or pappules on the trunk and proximal extremities, face usually spared
called geogrphical rash - looks like borders on a map with pale centre
is erythema marginatum painful
not pruritic or painful
time course of erythema marginatum
evanescent - waxes and wanes during the course of a day
can recur for weeks/months
are NSAIDs effective for erythema marginatum
NSAIDs and steroids not effective
minor JONES criteria
polyarthralgia
prolonged PR interval on ECG
Hx of rheumatic fever
fever
raised inflammatory markers
- CRP, ESR, leuks
investigations for acute rheumatic fever
bedside:
vitals and ECG- for prolonged PR interval
Labs:
FBC - raised WCC
ESR, CRP - raised
troponin - raised in carditis
strep serology (ASOT, antiDNaseB)
dependant on context: throat swab, skin sore swab, blood culture, synovial fluid aspirate
rheumatoid and anti-CCP to rule out other diagnoses
imaging:
Echo to aid carditis diagnosis
chest x-ray to rule out heart failure
ddx for joint symptoms
juvenile idiopathic arthritis
reactive arthritis
HSP- henoch-schonlein purpura
cardiac disease might otherwise be explained by
cardiomyopathy
kawasaki disease
infective endocarditis
chorea may be otherwise explained by
wilson’s disease
adverse drug reactions
huntington’s disease (very rare in children)
skin changes may be otherwise explained by
advserse drug reactions
Lyme disease/erythema migrans
erythema multiforme
treatment for strep throat infection in high risk groups
bed rest strongly recommended especilly if myocarditis is present
IM benzaathine benzylpenecillin G (BPG) is the antibiotic of choice, single dose
treatment for arthritis
paracetamol, tramadol if diagnosis unclear
NSAID if diagnosis confirmed
immobilise
carditis treatment
diuretics, ACEI
pericardiocentesis to remove fluid collections around the heart (in presence of pericardial effusions) may be needed
treat heart failure as required
chorea treatment
dizepam, haloperidol,
carbamazepine, valpproate
if functional impairment but this symptom is self limiting
complications of acute rheumatic fever
carditis
heart fialure
pericardial effusions
valvular disease (especially the mitral valve)
atrial fibrilltion
pulmonary hypertension
thromboembolic events
refractory chorea (plasmapheresis may be required
what causes rheumatic heart disease
similarities between the streptococcal bacteria and human heart valve tissue lead to autoimmune damage to the hert valves
prevelence of rheumatic heart disease
peak prevalence in thrid or forth deecades
more common in females
mitral valve most commonly affected
echo: gold standard for diagnosis
symptoms of rheumatic heart disease
may be asymtpomatic
dyspnoea: on exertion, orthopnoea, paroxysmal nocturnal dyspnoea
fatigue, weakness
angina
syncope
signs of rheumatic heart disease
heart murmur
heart failure
arrythmia
natural history of rheumatic heart disease
primordial prevention of rheumatic heart disease
disease of poverty
overcrowding
washing facilities for people, clothing, bedding
primary prevention of rheumatic heart disease
regognise strep throat and skin infections and treat with antibiotics
secondary prevention of rheumatic heart disease
consistent and regular administration of antibiotics to people who have had ARF or RHD, to prevent future GAS infections, ARF recurrence, and thus limit RHD development/progression
use long-acting intramuscular benzathine penicillin G (BPG)
duration depends on: ARF classification, presence of RHD (and its classification), age
