Burden of ARF and RHD
- most commonly seen in 5-14 year olds - females are more likely to be diagnosed with ARF - 1 in 5 patients will have a recurrent episode of ARF within 10 years of their first episode - 50% of patients will progress to RHD within 10 years after their initial ARF (if severe or recurrent ARF)
What are the 2 main social determinants of ARF?
- Overcrowded conditions 2. Limited access to facilities to wash people, clothes and bedding Both increase the risk of strep A infections
Which bacterial causes ARF?
Group A streptococcus - human only infection, nil animal reservoirs
What are the 9 health living practices and their association with group A strep?
- Washing people (strong) 2. Washing clothes and bedding (medium) 3. Remove wastewater (weak) 4. Improve nutrition and ability to store and cook food (weak) 5. Reduce overcrowding (strong) 6. Reduce negative affects of animals i.e. cuts/skin damage and scabies (medium - indirect) 7. Reduce health impact of dust (weak) 8. Controlling temp of living environment (weak) 9. Reduce hazards that cause trauma (mediuM0 These were developed in 19080s by Nganampa Health Council in South Australia.
Describe primary prevention of ARF.
- aim is to interrupt link between strep A infection and abnormal immune response to strep A that causes ARF - this is done by early identification of strep A infections - treatment of strep A sore throat with Abx can reduce development of ARF by up to two-thirds
How common is strep A in relation to sore throats?
- associated in up to 37% of sore throats - present in 10-40% of children with sore throats - associated in up to 82% if impetigo episodes
Describe the high risk group for ARF.
- living in ARF endemic setting - Aboriginal and/or Torres Strait Islander people living in rural and remote settings - Aboriginal and/or Torres Strait Islander, Maori and/or Pacific Islander people living in metro households affected by overcrowing or lower SES - personal history of ARF/RHD and aged <40
Recommended Abx for strep throat/tonsillitis?
1) Benzathine benzylpenicillin (BPG) - deep IM, once off dosing 2) Phenoxymethylpenicillin - PO, for 10 days 3) Cefalexin –> if hypersensitive to penicillin (rash) - PO for 10 days 4) Azithromycin –> if anaphylactic to penicillin - PO for 5 days
Dosing for benzathine benzylpenicillin for strep throat.
<10kg: 450,000 units (0.9ml) 10-<20kg: 600,000 units (1.2ml) >20kgL 1,200,000 units (2.3ml)
Dosing for phenoxymethypenicillin for strep throat.
Child: 15mg/kg up to 500mg BD Adult: 500mg BD
Recommended antibiotic treatment for strep A skin sores in children with >1 purulent or crusted sores
1) Trimethoprim/sulfamethoxazol > 4mg/kg/dose of trimethoprim, BD for 3 days OR 2) benzathine benxylpenicillin (as per treatment for strep throat)
Signs suggestive for strep throat
Fever Swollen/enlarged tonsils Erythematous tonsils with exudate Enlarged and tender cervical lymphadenopathy Absence of cough (I.e. Centor Criteria)
What are the diagnostic classifications of ARF?
- definite ARF/definite recurrence - probable ARF/probable recurrence - possible ARF/possible recurrence
How soon should a patient with confirmed ARF be admitted/get a TTE?
Within 24-72 hours
ECG findings in ARF
- first degree heart block most common - second degree HB, complete HB and accelerated junctional rhythms occur in 8% of cases of ARF
Criteria for diagnosis of “definite initial episode” of ARF?
2 major manifestations + evidence of preceding strep A OR 1 major + 2 minor manifestation + evidence of preceding strep A
Criteria for diagnosis for recurrent episodes in ARF in patients with known ARF/RHD?
2 major manifestations + evidence of preceding strep A OR 1 major + 2 minor manifestation + evidence of preceding strep A OR 3 minor manifestations + evidence of preceding strep A
What are the major manifestations of ARF? (5)
- Carditis 2. Polyarthritis 3. Sydenham chorea 4. Erythema marginatum 5. Subcutaneous nodules ** note in high risk populations aseptic monoarthritis or polyarthralgia are classified as MAJOR manifestations
What are the minor manifestations of ARF? (4)
- Fever > 38.5 2. Monoarthralgia, polyarthralgia, aseptic monoarthritis 3. ESR > 30 OR CRP >30 4. Prolonged PR interval on ECG
Define evidence of preceding strep A infection serologically.
- elevated or rising antistreptolysin O or other strep antibody - positive throat culture - or positive rapid antigen/nucleic acid test for strep A infection
What are the upper limits of normal PR interval in a) 3-11 year olds b) 12-16 year olds c) >17 year olds
a) 0.16 b) 0.18 c) 0.2
Is ARF a notifiable disease?
Yes All causes should be notified to the local Disease Control Unit or Public Health Unit and registered with the RHD control program
What are the two most common clinical manifestations of ARF and their differences?
- Acute febrile illness: onset 2-4 weeks post GAS - Neurological illness: 25-30% of cases, later onset 2-6 mpst post GAS
Define primordial, primary, secondary and tertiary prevention of ARF/RHD.
- primordial: addessing social determinants of health
- primary: treatment of GAS infections with penicillin
- secondary: IM penicillin G to prevent recurrent ARF and RHD
- tertiary: treatment of established RHD
