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ACUTE RHEUMATIC FEVER
    Is an acute immunologically mediated, multisystem inflammatory disease that
      occurs a few weeks following an episode of Group A strep pharyngits.
    Occurs at all age groups except infancy, but incidence peaks between 5-15yrs, a
      period when strep infections are most frequent.
    20% of all attacks in middle to later life

Pathogenesis
Exact pathogeneses remains unknown but probable one is:
    Initial trigger – Grp A strep pharyngitis
    Colonization of pharynx with the Grp A beta hemolytic strep
    Immune response triggered by this colonization – sensitization of B lymphocytes
       by strep antigen mainly M antigen/M protein
    B cells proliferate and differentiate into plasma effector cells – produce antibodies
       against the M protein
    These antibodies crossreact with the glycoprotein antigens present in human
       connective tissues which are similar to M protein.(antigen similarity)
    Connective tissues affected are in heart (cardiac sarcolemma), joints (synovial
       membrane), skin and basal ganglia
    Ab binds with the glycoprotein Ag and forms immune complexes
    Activates complement system
    Inflammation and damage in the connective tissue affected

Key pathologic features
1) Heart – pancarditis (all three layers of the heart involved)
     Pericardium – fibrinous or serofibrinous pericardial exudates which resolves
      without sequelae
     Myocardium – scattered aschoff bodies within interstitial connective tissue
     Endocardium – fibrinoid necrosis within cusps or along tendinous cords on which
      sit small 1-2mm vegetations known as verrucae along lines of closure

2) Joints – swelling of the articular and periarticular structures with infiltration of
synovial membrane by lymphocytes and plasma cells and serous effusion into the joint
space. However never erosion of joint surface.

3) Brain – cellular degeneration and hyalinization of small blood vessels scattered
throughout the cerebellum, cortex and basal ganglia. (no site consistently involved)

4) Skin – nodules form which contain a central area of fibrinoid necrotic material
surrounded by fibrolasts and occasional lymphocytes.
- rash occurs due to increase permeability of cutaneous blood vessels

Clinical Manifestations & Diagnostic criteria
ARF is characterized by a constellation of findings that includes as major manifestations
in Jones Criteria
JONES CRITERIA
MAJOR MANIFESTATIONS
1) Migratory polyarthritis
     75% of patients
     Affects several joints in quick succession, each for a short time. Knees, elbows,
       ankles and wrists are affected most commonly with leg joints typically being
       involved first
     Onset of arthritis in different joints usually overlap, giving appearance that
       disease migrates from joint to joint
     If left untreated, each joint is inflamed for only a few days and all joint symptoms
       usually disappear spontaneously in 3-4weeks, leaving no permanent deformities
2) Carditis
     40-50% of initial attacks
     Duration – 6wks-6mos
     Most serious manifestation since it can be fatal during acute stage
     Mild-moderate chest discomfort, pleuritic chest pain or pericardial friction rub are
       indications of pericarditis
     New or changing murmurs – apical high pitched blowing holosystolic murmur of
       at least grade 2 is indicative of mitral valvulitis (most common)
     Cardiomegaly maybe present on CXR at onset or during the course of acute attack
     There may be evidence of congestive cardiac failure
3) Subcutaneous nodules
     5% of patients
     Present for 1 or more weeks rarely >1mo
     Are 3 or 4 in number, when numerous then symmetric and vary from few mm to
       2cm in diameter
     Round hard freely movable painless swellings, usually overlying bone
       prominences or near tendons on joints, scalp and spinal column
4) Erythema marginatum
     5% of patients
     Characteristic skin rash of rheumatic fever – lesions begin as slightly red, barely
       raised nonpruritic macules that extend outward to form wavy lines or rings with
       sharp margins. Skin in centre becomes normal
     Occur mainly over trunk and inner surface of arms and legs
5) Chorea – Sydenham chorea
     10-15% of patients
     Neurologic disorder consisting of abrupt purposeless nonrhythmic involuntary
       movements, muscular weakness and emotional disturbances
     Individual attack is self limiting although it may last up to 3mos

MINOR MANIFESTATIONS
Clinical
   1) fever – usually low grade and present at onset of acute attack. It ranges from
       38.3-40C
   2) polyarthralgia – pain in 2 or more joints without heat, swelling and tenderness
   3) previous history of ARF or presence of inactive RHD
Laboratory
   1) Acute phase reactants – ESR and CRP – tests to measure the presence and degree
      of inflammatory process. Its not specific for ARF but useful for determining
      when the acute phase has terminated
   2) Leukocytosis
   3) Prolonged PR interval

DIAGNOSIS – presence of 2 major or
                  1 major + 2 minor manifestations
              + supporting evidence of preceding Group A strep infection
Exceptions
3 settings in which diagnosis of ARF could be made without strict adherence to Jones
Criteria:
1) chorea as only manifestation
2) indolent carditis as only manifestation in patients who come to medical attention
months after acute infection
3) recurrent RF in patients with history of RF or RHD

Evidence of recent strep infection
1) throat culture – should be +ve for group A beta hemolytic strep. Throat cultures are
-ve in 75% patients by the time RF appears but an attempt should be made to isolate the
organism

2) streptococcal antibodies – more useful since they reach a peak at about time of onset
of RF and indicate true infection rather than a transient carriage.
- antistreptolysin O – inc. ASO titre. After strep infection this antibody peaks at about 4-
5wks. 80% patients have increased titres.
- serum specimen taken at time of diagnosis of ARF first suspected and 1-2wks later for
comparison. The titer falls off rapidly after 2mos and reaches a slower decline after 6mos.
Thus if –ve titre – test for other strep antibodies – anti DNAse B, streptokinase and
antihyalurodinase. These are detectable 6-9mos following infection

TREATMENT
3 major goals:
1) Symptomatic relief of acute disease manifestation.
2) Eradication of group A beta hemolytic strep
3) Prophylaxis against future infection to prevent recurrent cardiac disease

      Symptomatic relief – anti inflammatory agents most commonly aspirin.
       Dramatic improvement is seen in relief of arthritis and fever after start of therapy.
          - children – 80-100mg/kg/day
          - adults – 4-8g/day
          - duration varies. It should be maintained until all symptoms are absent and
             ESR and CRP are normal
       patients with severe carditis are often treated with corticosteroids – usual dose is
2mg/kg/day of oral prednisone for 1st 1-2wks. Depending upon clinical and lab response,
dose then tapered over next 2wks.
    Signs of mild heart failure – complete bed rest, oxygen, fluid restriction and
       steroids
    Complete bed rest for 2weeks and examined daily to detect if carditis present or
       not

      Eradication of grp A strep – antibiotic therapy regardless of presence or absence
       of pharygitis at time of diagnosis
           - oral dose pen V – children: 250mg 2-3x daily; adults: 500mg 2-3x daily
           - if compliance an issue: benzathine penicillin G single IMI dose – 1.2mill
              units (chn >27kg and adults); 600,000units (chn < 28kg)
           - allergic to penicillin – erythromycin – 40mg/kg/day in 2-4doses

      Prophylaxis
           - Primary prevention – treating all sore throats by giving antibiotic –
               benzathine penicillin injection (drawback- 80% sore throat caused by
               virus)
           - Secondary prevention – to prevent recurrence of ARF which is most
               common within first 2 yrs of original attack but can happen anytime.
               - benzathine penicillin G 1.2mill units IMI every 3 wks
            - Tertiary prevention – is when RHD has developed and presence of a
                Valvular lesion – valve replacement
      Infective endocarditis prophylaxis – given if murmur or carditis is detected or
       when there is RHD – high dose amoxicillin 1 hr before surgical or dental
       procedures and 6hrs after.

Sequelae
Rheumatic heart disease – occurs usually 10-20yrs after original attach and major cause
of acquired valvular disease in the world.

Kaynaat shama ali
Mbbs 4 - 060208