Tropical medicine for you and your patients. Phil Blum Darwin 2018

Transcription

1 Tropical medicine for you and your patients Phil Blum Darwin 2018

2 What we are going to cover What disease risks you may face A brief discussion of the big 3 Dengue, Zika and others (time permitting)

3 Top global causes of death LIMC WHO 2016 Pneumonia Diarrhoea Ischaemic heart disease HIV/AIDS Stroke Malaria TB Perinatal death Road trauma

4 Changing burden of disease 2016: the number of overweight humans out -numbered the number of underweight

5 Low-middle SDI 1990

6 Low-Middle SDI 2016

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8 They die from: Pneumonia Diarrhoea Malaria Measles HIV Overview

9 Pneumonia Step pneumoniae most common cause Management includes reliable oxygen supply Empyema Bronchiectasis

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11 Prevention is better than cure Vaccinations Mosquito prevention Food and water hygiene Road trauma Malaria prophylaxis Don t pat puppies/monkeys/bats Condoms Post exposure prophylaxis

12 What might happen to you on a short service mission For every travellers to the real world for one month: 1000 will be incapacitated in their work either abroad or on their return 300 will be admitted to hospital 50 will have to be air evacuated (0.05% 1:2000) one will die

13 What you might catch 8% travelers to the real world will require medical care Acute and chronic diarrhoea Febrile illness - Dengue, Malaria Dermatological disorders Respiratory complaints STI s

14 Get expert ID advice Up to date with: DTP MMR Polio Influenza Hep B, Hep A Typhoid Cholera Vaccinations

15 Vaccinations If prolonged and/or rural travel to affected areas, consider vaccinations for: Rabies JE Meningococcus Yellow fever BCG And keep a record

16 Mosquitoes Clothing cover up with light coloured clothes DEET repellent 20% Pyrethroid-containing flying-insect spray in living and sleeping areas during evening and night-time hours Permethrin-impregnated bed nets Ensure no standing water about your house

17 Hygiene hand washing avoiding drinking untreated water avoid eating raw vegetables, seafood etc

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19 The big three HIV/AIDS TB Malaria

20 HIV/AIDS - your patient 33 million worldwide living with HIV HIV prevalence by area Implications for anaesthesia

21 HIV/AIDS - you Risk of transmission Personal protective clothing If needle-stick injury: Wash Post exposure prophylaxis Basic regime Expanded regime Seek expert advice from your friendly ID physician

22 HIV/AIDS If source patient is on ARV already, talk to expert about what to use for PEP If going to a high-prevalence country, bring a course of HIV PEP with you if possible

23 TB - your patient 1/3rd of the world infected Now often associated with HIV Multi-Drug Resistant: MDR TB Extensively Drug Resistant: XDR-TB First reported Now widespread drug susceptibility testing now rapid mortality if also con-infected with HIV improving

24 TB -transmission Airborne spread!

25 TB - you Make sure you know your status (mantoux) BEFORE travel Wearing of n95/p2 masks desirable but not always practical in high-prevalence areas BCG vaccination now recommended again

26 Malaria - your patient Presents as: Fever, rigor and chills Textbook periodic fever uncommon Flu-like In non-immune commonly mimics gastro Nausea, vomiting and abdo pain

27 Malaria Vector = Anopheles mosquito P.Falciparum P.Vivax P.Ovale P.Malariae P.Knowlsei Falciparum responsible for majority of deaths

28 Severe Malaria A parasitaemia of 5% Altered consciousness Oliguria Jaundice Severe normocytic anaemia Hypoglycaemia Organ failure

29 Malaria - you In travellers usually due to lack of or inappropriate chemoprophylaxis Doxycycline daily Reflux and indigestion Photosensitization Atovaquone and proguanil (Malarone) Mefloquine (Lariam) go crazy on holidays! oral artemether / lumefantrine (co-artemether) as standby treatment in low risk areas

30 Malaria Diagnosis of thick and thin films plus serology May need multiple slides

31 Malaria Artemisinin based combination therapies IV Artesunate for 3 days followed by oral agents - currently treatment of choice in Australia oral artemether / lumefantrine (co-artemether) IM Artemether Artemisinin suppositories Exchange transfusions

32 Dengue fever Mosquito borne virus (arbovirus) Flavivirus Multiple serotypes Urban

33 Dengue fever Clinical Haemorrhagic fever dengue haemorrhagic shock dengue shock syndrome Now Severe dengue Treatment - supportive

34 Dengue fever Dengue without warning signs Dengue with warning signs Abdo pain/persistent vomiting Ascites /pleural effusion Mucosal bleeding Increase in Hct concurrent with rapid fall platelets

35 Severe dengue fever One of the following: severe plasma leak shock/pulmonary oedema severe bleeding Severe organ involvement AST or ALT > 1000 impaired consciousness overt failure

36 Zika virus Initially isolated from monkeys in the Ugandan Zika forest in 1947 World-wide and spreading Asymptomatic in 80% cases up to 2/3rds of a population can become infected 20% have low grade fever, maculopapular pruritic rash, small joint arthralgia and nonpurulent conjunctivitis

37 Zika virus Onset 2-14/7 Symptoms are generally mild and last 2-7/7 Neurotropism so associated with congenital microcephaly, Guillain Barre syndrome, myelitis and meningoencephalitis Rates of microcephaly vary depending on population

38 Zika virus serology is tricky as tests can cross-react with other flaviviruses vaccine phase 1 trials treatment is supportive

39 Zika virus Can be spread sexually or by blood transfusion It is recommended that if you have visited an area with Zika present, don t engage in unprotected sex for 6 months

40 Yellow fever Flavivirus Urban - Aedes aegypti Jungle Forest species Most short viral illness with vomiting Initially indistinguishable from dengue

41 Encephalitis West Nile encephalitis Japanese encephalitis Murray Valley encephalitis Flavivirus Mainly asymptomatic High fatality rate if symptomatic

42 Chikungunya Aedes aegypti Alphavirus Ross River Fever and Barmah Forrest Fever are also caused by Alphaviruses acute febrile polyarthritis arthritis 2-5 days following onset of fever symmetrical polyarthritis includes hands, wrists and ankles

43 Chikungunya pain is intense and disabling associated with maculopapular rash in around 50% cases polyarthritis persists for 6 months in 50% cases diagnostic serology IgM and IgG anti- Chikungunya virus antibodies treatment is supportive only no vaccine is available.

44 Aedes aegypti management Endosymbiotic control with Wolbachia bacteria Shortens mozzie life, vertical transmission, reduces viral replication Possible game changer

45 Rabies Virtually uniformly fatal Rabies virus is shed in saliva. Thoroughly wash bites and scratches with soap and water

46 Rabies vaccine and immune globulin (passive immunisation) Rabies vaccination and passive immunisation is effective Rabies vaccine is used for preexposure prophylaxis given IM - 3 doses (Day 0,7,21) if a vaccinated person is bitten then urgent postexposure prophylaxis consists of: - 2 doses of IM rabies vaccine ASAP (Day 0 and 3)

47 Bitten and no vaccination? Urgent postexposure prophylaxis consists of: - 1 doses of IM human rabies immune globulin (HRIG) - 4 or 5 doses of IM rabies vaccine, which needs to be refrigerated (Day 0, 3, 7, 14, 28)

48 EVD Low infectious dose High virus titres in blood of ill patients Severity of disease It is not so much the fear and chaos of an EVD outbreak that should worry us but the more mundane policy decisions that occur behind closed doors

49 Asymptomatic individual in the incubation period are NOT considered infectious NOT AIRBOURNE spread Ebola virus destroyed by hypochlorite solution

50 The neglected tropical diseases The disease burden from these diseases, as measured by DALYs lost, equals that of HIV/AIDS, TB and Malaria combined. Inexpensive oral therapies exist to treat many of these conditions Currently 17 on WHO list plus 5 Other Neglect conditions

51 Others Scabies Melioidosis Leptospirosis Ciguatera poisoning Envenomation Typhus STI s

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53 Resources

54 Prevention is better than cure Vaccinations Mosquito prevention Food and water hygiene Wear a seat belt Malaria prophylaxis Avoid animals PEP Condoms