Travel Infections Flashcards
If a travel infection isn’t treated with antibiotics what kind of differential diagnosis are you thinking?
Parasite - maybe malaria
Why is travel history important?
Gives idea of imported diseases
Helps identify treatment
Different strains of pathogen antigenically different
Antibiotic resistance
What should you ask in the travel history?
When they went When they came back Have they been in contact with anyone unwell Pre travel vaccinations Preventative measures Recreational activities Healthcare exposure
What are symptoms/signs malaria?
Sometimes NONE
Othertimes - Fatigue, fever, malaise, hepatosplenomegaly, fever can be tertian
What are the three most common species of malaria?
Plasmodium falciparum
Plasmodium ovale
Plasmodium vivax
What is the method of transmission of malaria?
Vector - female mosquito
Can you have case to case spread?
No
If the person has travelled from Africa what is the most likely plasmodium?
Falciforum
If the person has travelled from India what are the two most likely plasmodiums?
Ovale
Vivax
What is the incubation period?
Min 6 days
P falciform up to 6/12
P vivax/ovale up to 1 year
Why such a long incubation period?
Due to dormant stage in liver
On examination what might you see indicating malaria?
Not much apart from increased temp and splenomegaly
Which is the most severe malaria? Why? How much burden do you need?
Falciparum - only need 2% burden
Can lead to microvasc occlusion which can lead to cardiac problems, acute respiratory distress syndrome DIC CNS problems, tachy, diarrhoea etc.
What is the lifecycle of malaria in an infected human?
Malaria infected mosquito bites Releases sporozoites Travel to liver and infect liver cells Mature into schizonts Form merozoites Lyse and release into blood stream Infect RBCs - form more merozoites and so on...lyse etc Some meozoites become gametocytes - female mosquito feeding can pick up these gametocytes and become infected
What blood tests would you do for malaria? Other tests?
3 x blood films - thick and thin (thick looks at parasites in general - thin looks more closely at malaria parasites)
Rapid antigen test
Blood cultures - to check for bacterial origin FBCs - platlets/WBC/RBC etc LFTs - deranged Albumin - indication of liver function Bilirubin- raised in haemolysis due to breakdown of haem Glucose - gives hypoglycaemia Clotting if platelets low CRP - inflammation U and Es - affects kidneys
Chest Xray
What blood results might you see for malaria?
Positive blood film for parasite Positive antigen test Raised bilirubin due to haemolysis Deranged LFTs due to liver dysfunction Low/normal WBC Low platelets Hypoglycaemic
What is the treatment for malaria?
Falciparum - artesunate. quinine + doxycycline
Viviax and ovale - chloroquine and primaquine
Which enzyme deficiency disorder are you concerned about in someone with malaria?
G6PDH - as get haemolytic anaemia. Will be even worse with malaria
Why can’t you give chloroquine and primaquine to falciparum malaria?
Resistant
What is the ABC of malaria prevention?
A - assess risk/knowledge of area
B - bite prevention - clothes, nets, repellant
C - chemoprophylaxis - start before and continue after return
What are differentials for malaria?
Typhoid
Dengue
Rickettsial infection
Meningococcal septicaemia
If Salmonella typhi is on blood culture what is the diagnosis? Where would you catch this most likely? What from? What is the method of transmission? What is the incubation period? Symptoms?
Typhoid/paratyphoid
Asia
Poor sanitation
Falco-Oral - cases or carriers only - human pathogen
7-10 days
Fever headache abdominal discomfort constipation dry cough
Relative bradycardia
What is a major complication of salmonella typhi?
Intestinal haemorrhage and perforation - 10% mortality if untreated
What is the difference between typhoid/paratyphoid?
Paratyphoid is generally milder
