Aboriginal Health Flashcards
In which population groups should Strongyloidiasis be considered
Residents of endemic areas (tropical and subtropical Aboriginal communities), immigrants, refugees, veterans of WWII and Vietnam War, workers and travelers returning from endemic areas
How is a strongyloides infection caught
Larvae penetrate skin -> bloodstream -> pulmonary capillaries -> alveolar space -> ascend bronchial tree -> swallowed by host -> small intestine
There mature into worms -> penetrate mucosa -> lay eggs which hatch into larvae -> penetrate colonic wall or perianal skin and re-enter body via autoinfective cycle
Pathognomic sign of strongyloidiasis
Larva currens
Erythematous wavy lesions that appear and move rapidly (2-10cm/h)
Usually on trunk or buttocks
Signs and symptoms of strongyloidiasis
Highly variable, depending on site and number of worms, Can include:
Dyspnoea/lung symptoms
Prutirtus, recurrent rash/urticaria
Diarrhoea, wasting, epigastric pain, melaena
Gram-negative sepsis
Eosinophilia
Diagnosing strongyloidiasis
Acute or dissmeinated disease: faecal OCP
Chronic infection: serology (strongyloides IgG ELISA)
Intermittent eosinophilia in 10-70% of chronic cases
Management of strongyloidiasis in immunocompetent patients
Ivermectin 200 microg/kg with fatty food stat on day 1 and repeated 7-14 days later
OR Albendazole 400mg with fatty food BD fo 3 days then repeat after 7-14 days (lower cure rate, only used if ivermectin unsuitable e.g. due to concurrent Loa loa infection)
Management of strongyloidiasis in immunocompromised patients
Ivermectin 200microg/kg orally with fatty food on days 1, 2, 15, 16
Seek ID advice as may required longer courses of therapy
Strongyloides prophylaxis prior to commencing immunosuppression for patients at risk
If serology positive: ivermectin 200microg/kg orally with fatty food once weekly for 2 doases
If serology negative (from remote ATSI communities): ivermectin 200 microg/kg orally with fatty food as single dose
Ongoing primary prophylacis every 3 months recommended for patients requiring significant immunosuppression and returning to endemic communities
Criteria for cure of chronic strongyloidiasis
Negative serology
Negative faeces OCP
No symptoms
Peak age for acute rheumatic fever
5-20y
High risk groups for acute rheumatic fever
Those living in RF-endemic setting
ATSI people living in rural or remote setting
ATSI, Maori and Pacific islander peoples living in overcrowded housing OR of low SE status
Personal history of ARF/RHD and aged <40y
Primordial prevention of ARF
- washing of hands and bodies with soap and water
- wash clothing and bedding in a manner that kills lice and scabies (>50deg or tumble dried >40 min)
- reduce overcrowding
- reduce hazards that cause skin trauma (i.e clean and tidy yards)
Primary prevention of ARF
Recognise strep A throat and skin infections early in high risk populations
Early treatment
- throat: IM BPG or PO PMP (inferior)
- skin: IM BPG or PO cotrimoxazole (non-inferior)
Presentation of ARF in Australia
High rate in Australia of arthritis being the only major manifestation
Major manifestations:
- ARTHRITIS:
- very responsive to NSAIDs
- large joints usually affected (esp knees and ankles)
- usually asymmetrical and migratory but can be additive - Sydenham Chorea:
- predominantly affects female teenagers
- jerky, uncoordinated movements of hands, feet, tongue and face
- disappear during sleep
- can occur after a prolonged latent period following GAS, therefore diagnosis does not require other manifestations or strep titres
- high association with carditis - CARDITIS
- predominantly endocardial involvement -> valvulitis
- may not appear until 6 weeks after presentation
- most common findings: significant murmur (MR or AS), cardiac enlargement (apex beat, echo or CXR), cardiac decompensation (<10% in initial episode but more common in recurrence), pericardial friction rub or effusion - SUBCUTANEOUS NODULES
- very rare (<2% of cases) but highly specific
- 0.5-2cm round, firm, freely mobile, painless
- occur in crops of up to 12 over elbows, wrists, knees, ankles, achilles, occiput and posterior spinous processes
- appear 1-2 weeks after onset of other symtpoms and only last 1-2 weeks
- strongly associated with carditis - ERYTHEMA MARGINATUM
- very rare (<2%) but highly specific
- bright pink macules or papules
- blanching
- wax and wane rapidly during the day
- not itchy or painful
- on trunk and proximal extremities
- more apparent after a shower
Diagnostic criteria for definite initial episode of acute rheumatic fever
2 major manifestations + evidence of preceding GAS infection
OR
1 major + 2 minor manifestations + evidence of preceding GAS infection
Diagnostic criteria for recurrent episode of ARF in a patient with documented history of ARF or RHD
Evidence of preceding GAS infection PLUS 1. 2 major manifestations OR 2. 1 major + 2 minor manifestations OR 3. 3 minor manifestations
Definition of probable or possible episode of acute rheumatic fever
Clinical presentation where ARF is considered likely but falls short in meeting diagnostic criteria by either:
- 1 major or 1 minor manifestation
OR
- No evidence of preceding GAS infection
Major manifestations of acute rheumatic fever
Subcutaneous nodules Pancarditis Poly ARTHRITIS (or in high risk groups aseptic monoarthritis or polyarthralgia) Chorea (Sydenham's) Erythema marginatum
Minor manifestations of acute rheumatic fever
CAFE:
CRP>30 or ESR>30 (or ESR>60 in low risk groups)
Arthralgia (monoarthralgia in high risk group, polyarthralgia or aseptic monoarthritis in low risk groups)
Fever >38 (of >38.5 in low risk groups)
ECG changes (prolonged PR interval)
Evidence of Group A Stretococcus required for diagnosis of ARF
EITHER
- Throat swab (poorly sensitive)
- Streptococcal antibody titres
- ASO titre (rises within 1-2 weeks, peaks 3-6 weeks, returns to pre-infection after 6-12 months)
- Anti-DNase B (takes 6-8 weeks to peak, can remain elevated indefinitely during childhood)
**take titre values in acute stage and repeat in convalescent phase 14-28 days later (positive = 2 fold increase or more)
Work up recommended for suspected acute rheumatic fever
Admission to hospital is recommended
- strep serology
- inflammatory markers (CRP and ESR>30)
- ECG
- Echocardiography - all patients with suspected ARF require within a maximum of 4 weeks
- blood cultures if documented fever
- joint aspirate if monoarthritis (and treat as per septic arthritis while awaiting results)
Short term management of suspected ARF
- notify public health unit (all suspected and confirmed new or recurrent)
- Eradication antibiotics: Give first dose of benzathine penicillin IM ASAP (1.2million units unless <20kg)
- Symptom management
- Pain: paracetamol +/- tramadol while awaiting diagnostic confirmation, NSAIDs following diagnosis
- Chorea: no txif mild, if mod-severe: CBZ or valproate, if very severe consider oral prednisolone 1-2mg/kg/day
- Carditis: if CCF, seek specialist advice. Bed rest, frusemide, fluid restriction, spironolactone, enalapril
Long term management following episode of ARF
Education: primordial and “primary” prevention strategies, education of disease and importance of adherence etc.
Immunisations up to date including annual fluvax
Antibiotic prophylaxis: Benzathine benzylpenicillin 1.2 million units (or 0.6million if<20kg) every 28 days OR every 21 days if breakthrough on 28 day regime or mod-severe carditis. (Oral BD erythromycin if penicillin allergy)
Duration to continue prophylactic antibiotics following acute rheumatic fever
- POSSIBLE ARF: 12 months if no signs or symptoms and normal echo at 12 months
- PROBABLE ARF: 5 years OR until 21yo (whichever is longer)
- Definite ARF without RHD: 10 years(min 5y) after most recent episode or until 21yo (whichever longer)
- ARF with mild RHD: minimum 10y or 21yo
- moderate RHD: until 35yo
- Severe RHD or post cardiac valve surgery for RHD: until 40y OR lifelong if very severe
Recurrent episodes of acute rheumatic fever - statistics
Most likely to occur in the first year after ARF diagnosis- then risk continues to decrease over next 5-10 years
Many cases will mimic the initial episode (but can also be non-mimetic, hence why prophylaxis is important even if no carditis in initial episode)
