Fever of traveler return from tropical area (1)

Author

Dr. Poon Kin Ming

Oct, 2013

HKCEM College Tutorial

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

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

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

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 +

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

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

Patient with fever after return from tropical region

▪What is your differential diagnosis in general ?

Diagnosis

▪Infectious diseases esp. tropical illness

▪Autoimmune diseases▪Malignancy

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

What is tropical region?

Continent visited

Destination Common Occasional

Sub Saharan Africa

Malaria, Rickettsial dis.

Dengue, Enteric fever,

brucellosis

South East Asia Malaria,Dengue,

Enteric fever

Leptospirosis,

Chikungunya

South & central Asia

Malaria,Dengue,

Enteric fever

Chikungunya

Latin American & Caribbean

Malaria,Dengue,

Enteric fever

Leptospirosis, Histoplasmosis

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

Fever pattern

Pattern Description Diseases Continuous Constant fever with

variation <1 °CTyphoid 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

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

Clinical diagnosis

▪ Dengue fever,

▪ Infectious mononucleosis,

▪ Influenza,

▪ Rickettial infection,

▪ Malaria,

▪ Typhoid fever

▪ Other non-infectious causes e.g. malignancy, auto-immune

Patient’s progress – fever pattern

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

Progress – lab. result

Day 1 2 4 8

WCC 3.9 2.5 1.9 4.2

HGB 14.9 15.1 16.8 13.8

Platelet 100 78 49 128

Haematocrit

43% 46% 49% 41%

APTT 28 33 42.1 26

ALT 20 134 305 42

BP 115/50 108/52 95/45 128/62

Day 1 Admission to Medical

D 2 Remained fever. Clotting profile & LFT impaired.

Influenza –ve

D 3 Monospot test –ve

Doxycycline was added to cover rickettial infection

D 4 Fever down. Appetite improved

Blood culture – ve

D 5 Dept of Health : PCR +ve for Dengue fever serotype 1. Doxcycline stopped

D 8 WCC, ALT & platelet returned to normal

D 9 Discharge

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

Aedes Aegypti 埃及伊蚊

www.giron.co.cu/es/noticia/social/lucha-contra-el-aedes-aegypti-alertas-en-todo-momento

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)

http://www.niaid.nih.gov/SiteCollectionImages/topics/denguefever/michaelRossmannStory.JPG

Dengue Hemorrhagic fever

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

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

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

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

Summary

▪ Tropical infection, especially the Dengue fever, Malaria, Rickettsial diseases & Typhoid & Paratyphoid

▪ Protection against the vector (mosquito)

▪ Chemoprophylaxis against malaria before the trip

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.

ANY QUESTIONS ?