1. Fever of traveler return from tropical area (1) Author Dr. Poon Kin Ming Oct, 2013 HKCEM College Tutorial

2. A case ▪ 50/M, smoker, GPH ▪ C/O fever for 5 days ▪ Also has sore throat, cough, myalgia, poor appetite, chills, headache ▪ SOB, chest pain –ve ▪ Seen GP once and just partial improvement ▪ Recalled travel history to Thailand 10 days ago for a trip ▪ Vitals stable

3. ▪ What would you like to ask more in the history ?

4. History ▪ TOCC What does it stand for ? - Others symptoms ? -Chemoprophylaxis or vaccination before the trip -Mosquito bite / insect bite /animal contact -Onset of fever : Incubation period -Fever pattern

5. On further history ▪ Travel : Thailand for 4 days, noted fever 2 days after back to HK ▪ Occupation : teacher ▪ Contact / cluster –ve ▪ No chemoprophylaxis or vaccination before the trip ▪ Mosquito bite +

6. Physical exam: ▪ Alert, responsive ▪ Temp 38.1C, Jaundice & pallor –ve ▪ BP118/55mmHg, Pulse 88/min ▪ RR 16/min, SpO2 98% on RA ▪ Chest clear & no heart murmur ▪ Pharynx congested + ▪ A 1cm lymph node over L side of the neck ▪ Maculopapular skin rash over the body, petechiae –ve ▪ Neck stiffness –ve ▪ Liver & spleen not palpable ▪ Multiple joints pain but calf soft

7. Measles-like skin rash ▪ The rash consists of macular lesions that are red and usually 2–10 mm in diameter but may be confluent in places ▪ Morbilliform refers to a rash that looks like measles http://upload.wikimedia.org/wikipedia/commons/9/91/Denguerash.JPG

8. Patient with fever after return from tropical region ▪ What is your differential diagnosis in general ?

9. Diagnosis ▪ Infectious diseases esp. tropical illness ▪ Autoimmune diseases ▪ Malignancy

10. Infectious diseases that should not be missed Protozoal Malaria 瘧疾 Virus Dengue fever 登革熱 Rickettsial diseases 立克次氏體病 Chikungunya fever 基孔肯雅熱 Yellow fever 黃熱病 Bacterial Typhoid & Paratyphoid 傷寒及副傷寒 Leptospirosis 鈎端螺旋體病 Brucellosis 布魯氏桿菌病 Relapsing fever 回歸熱

11. What is tropical region?

12. Continent visited DestinationCommonOccasional Sub Saharan Africa Malaria, Rickettsial dis. Dengue, Enteric fever, brucellosis South East AsiaMalaria,Dengue, Enteric fever Leptospirosis, Chikungunya South & central Asia Malaria,Dengue, Enteric fever Chikungunya Latin American & Caribbean Malaria,Dengue, Enteric fever Leptospirosis, Histoplasmosis

13. Incubation periods Short (<10days) Acute gastroenteritis, Respiratory tract infection, Dengue, Chikungunya, Relapsing fever, Rickettsial infection Medium (10-21days) Malaria, Enteric fever, Brucellosis, Leptospirosis, Q fever, viral hemorrhagic fever Long (> 3 weeks) Malaria, Brucellosis, Schistosomiasis, Tuberculosis, amoebic liver abscess

14. Fever pattern PatternDescriptionDiseases Continuous Constant fever with variation <1 °C Typhoid fever, Rickettsial infection, encephalitis Intermittent Temperature returns to normal at least once during the day Malaria, Dengue fever, Leptospirosis, many viral illness, abscess Remittent Fever does not return to normal each day Typhoid fever, Tuberculosis, endocarditis Relapsing Recurrent over days & weeks Relapsing fever, brucellosis, malaria, lymphoma

15. Physical signs Maculopapular rash Dengue, rickettsial infection, leptospirosis (Rose spot in typhoid fever, Splinter hemorrhage in infective endocarditis, Eschar in scrub typhus) Lymphadenopathy Dengue fever, rickettsial infection, rubella infection Splenomegaly Malaria, dengue fever, typhoid fever, rickettsial infection, relapsing fever, brucellosis Hepatomegaly Viral hepatitis, malaria, typhoid fever, leptospirosis Haemorrhage Dengue fever, dengue hemorrhagic fever, meningococcal septicaemia

16. Clinical diagnosis ▪ Dengue fever, ▪ Infectious mononucleosis, ▪ Influenza, ▪ Rickettial infection, ▪ Malaria, ▪ Typhoid fever ▪ Other non-infectious causes e.g. malignancy, auto- immune

17. Patient’s progress – fever pattern

18. Investigation ▪ WCC : 3.9 (N : 4.5 -11x 10 9 /L) Differential count : neutropenia & lymphopenia ▪ HGB :14.9 (N : 14 – 17.5 x 10 9/ L ) ▪ Platelet : 100 (N: 150 – 450 x 10 9/ L) ▪ INR normal ▪ APTT prolonged to 42.1 sec ▪ R/LFT normal ▪ Malaria parasite –ve

19. Progress – lab. result Day 1248 WCC3.92.51.94.2 HGB14.915.116.813.8 Platelet1007849128 Haemat ocrit 43%46%49%41% APTT283342.126 ALT2013430542 BP115/50108/5295/45128/62

20. Day 1Admission to Medical D 2Remained fever. Clotting profile & LFT impaired. Influenza –ve D 3Monospot test –ve Doxycycline was added to cover rickettial infection D 4Fever down. Appetite improved Blood culture – ve D 5Dept of Health : PCR +ve for Dengue fever serotype 1. Doxcycline stopped D 8WCC, ALT & platelet returned to normal D 9Discharge

21. Dengue fever 登革熱 ▪ A viral disease transmitted by the infected mosquito, Aedes aegypti ( 埃及伊蚊 ) ▪ In HK, most abundant species is Aedes albopictus ( 白紋伊蚊 ) ▪ 4 dengue virus serotypes ▪ Most common serotype in HK is type 1 ▪ A statutory notifiable diseases in HK ▪ About 3-17 cases per year

22. Aedes Aegypti 埃及伊蚊 www.giron.co.cu/es/noticia/social/lucha-contra-el-aedes-aegypti-alertas-en-todo-momento

23. Dengue fever ▪ Incubation period of dengue infection is 4 to 7 days ▪ Fever usually lasts for 5 to 7 days ▪ Another name : break bone fever ▪ Clinical presentation ranges from non- specific febrile illness to severe life threatening conditions such as dengue hemorrhagic fever (DHF) & dengue shock syndrome (DSS)

24. http://www.niaid.nih.gov/SiteCollectionImages/http://www.niaid.nih.gov/SiteCollectionImages/topics/denguefever/michaelRossmannStory.JPG Dengue Hemorrhagic fever

26. Dengue fever 登革熱 ▪ Dengue hemorrhagic fever (DHF) : Dengue fever + Hemorrhagic tendency + Plasma leakage (>20%) -Dengue shock syndrome : (DSS) DHF + shock + rapid pulse with narrow pulse pressure < 20mmHg

27. Pathophysiology of DHF & DSS ▪ Rarely occurs in primary infection as host develops life long immunity only against specific serotype ▪ In secondary infection with another serotype, the a/b at primary infection cross reacts & forms complexes with viral antigen, which enhances the phagocytosis by mononuclear cells. ▪ The virus replicates inside the cells, which release the vasoactive immune mediators causing DHF & DSS

28. http://mednews.com/wp-content/uploads/dengue-virus-296x300.jpg

29. Treatment ▪ Mainly supportive ▪ Steroid & antiviral agents not effective ▪ Paracetamol as antipyretic agent ▪ Avoid aspirin as worry of Rye’s syndrome ▪ No vaccine available ▪ Vector (mosquito) control

30. Summary ▪ Tropical infection, especially the Dengue fever, Malaria, Rickettsial diseases & Typhoid & Paratyphoid ▪ Protection against the vector (mosquito) ▪ Chemoprophylaxis against malaria before the trip

31. Summary ▪ Exclusion of life threatening infection or diseases with public health risk (e.g. measles, rubella) is the priority ▪ Life threatening infections include Falciparum malaria, dengue haemorrhagic fever/ dengue shock syndrome, leptospirosis, infective endocarditis and meningoccocaemia.

32. ANY QUESTIONS ?