Microbiology 24 - Fever in the Returning Traveller + PUO Flashcards
Recall some differentials for fever and rash in the returning traveller
Viral: dengue, chickungunya, measles
Bacterial: typhoid (look for rose spots)
Recall some differentials for fever and abdo pain in the returning traveller
Typhoid fever
Amoebic liver abscess
Recall some differentials for fever and cytopaenias in the returning traveller
Dengue, chickungunya, typhoid (anaemia), malaria
**the mosquito ones + typhoid
Recall some differentials for fever and haemorrhage in the returning traveller
Viral haemorrhagic fevers (dengue/ ebola)
Meningococcaemia
Recall a differential for fever and eosinophilia in the returning traveller
Schistosomiasis
Recall some differentials for fever > 6 weeks post-travel in the returning traveller
Vivax malaria
Acute hepatitis
TB
Amoebic liver abscess
What % of parasitaemia constitutes a severe malaria?
>2%
What type of mosquito carries malaria?
Female Anopheles
Recall the different types of malaria
Falciparum
Vivax
Ovale
Malariae
Knowelsi
What acid base abnormality may be seen in malaria?
Metabolic acidosis
Why is malaria sometimes known as ‘blackwater fever’?
Due to the haemaglobinuria
What is the gold standard test for malaria?
Thick and thin blood films
What type of mosquito is a vector for dengue virus?
Aedes
What are the symptoms of dengue?
Fever
Headache
Myalgia
BLANCHING RASH - this spares the hands and feet (unlike chickengunya)
What cytopaenias are expected in dengue infection?
Thrombocytopaenia
Neutropaenia
What are the possible causative organisms in typhoid (enteric) fever?
Salmonella typhi/ paratyphi
What is the phrase “himalaya peak fevers” pathognemonic for?
Typhoid fever
What is the treatment of typhoid fever?
Ceftriaxone then azithromycin
What is the definition of pyrexia of unknown origin?
>38.3 degrees on several occaisons persisiting >3/52 without diagnsois depsite 1/52 of intensive investigations
What are the 3 types of PUO?
- classical
- healthcare associated
- neurtopaenic PUO
- HIV associated PUO
What can cause PUO?
What are some common causes of fever in a returning traveller?
Causes: tropical diseases (especially malaria, typhoid, dengue, viral haemorrhagic fevers), bacterial diarrhoea (E. coli, cholera) - Don’t forget about common UK causes too, e.g. UTI, pneumonia, influenza - Beware of questions pointing you towards STIs (e.g. HIV seroconversion)
What causes typhoid?
salmonella typhi or parathyphi
anaerobic gram -ve bacilli
symptoms of typhoid fever
Travel to India, transmitted in food and water, incubation 1-2wks
• Causes enteric fever by infecting Peyers patches in intestines
o Fever, headache, constipation (not diarrhoea!) o Rose spots, relative bradycardia, hepatosplenomegaly
treatment of typhoid fever
IV ceftriaxone –> PO azithromycin
need to vaccinate them as well
**need to treat them as it can cause GI perforation**
What type of virus is dengue virus? what transmits it?
flavivirus
transmitted by ades mosquito
Where is dengue commonly spread from?
South-East Asia, urban environments, short incubation (days)
**think vietnam**
symptoms of dengue
myalgia, fever, rash. Reasonably mild + self-limiting
**not as bad as malaria (but bad if you get infected again with a different serotype**
what causes dengue haemorrhagic fever?
if you get re-infected with a different serotype
**rare in travellers - as uncommon to be re-infected
needs supportive management
what type of infection is malaria?
protozoal infection (Plasmodium spp.)
spread by female anopheles mosquito- bites at
night, attracted by heat + CO
Areas of the world: Asia/africa/south america
classification of malaria
falciparum and non-falciparum
**falciparum - most common and most severe
**non-falciparum: P. vivax, p ovale, p malariae, p knowlesi
Treatment of non-falciparum malaria
Chloroquine then primaquine
(c then p)
primaquine prevents relapse of symptoms as non falciparum malaria has a hypnoxzoite stage
Pattern of fever in non-falciparum malaria
All 48 hour (tertian fever) except for P. malariae - 72h fever
What do you see on blood film in non-flaciparum malaria?
schuffner’s dots
What pattern of fever do you get in falciparum malaria?
tertian fever (48 hourly)
investigations for falciparum malaria
thick and thin blood films - x 3
thick- shows malaria
thin - shows the species
treatment of falciparum malaria
Mild: artemesin combination therapy (Riamet – artemether + lumefantrine) § Severe: IV artesunate
Features of severe falciparum malaria
What infections are spread through mice?
Hantan viruses(fleas), Lyme borreliosis, Ehrlichia, Bartonella Lymphocytic choriomeningitis
What infections are spread by rats?
Rabies, Leptospirosis, Lassa fever, Hantan viruses, Plague, Pasteruellosis, Haverhill fever (Rat-bite)
what diseases can be spread by cats?
Bartonellosis (cat scratch), Leptospirosis, Q-Fever, Toxoplasmosis, Rabies,
Ringworm, Toxocariasis
what diseases are spread by dogs?
Hydatid disease, Leptospirosis, Brucellosis, Q-Fever, Rabies, (MRSA!!), Ringworm,
Toxocariasis
what diseases are spread by small ruminants
Anthrax, Leptospirosis, Brucella, Bovine TB, Anaplasmosis, Toxoplasmosis,
E. coli 0157, Rift Valley fever, Ringworm
what diseases are spread by swine?
Brucellosis, Leptospirosis, Erysipeloid, Cysticercosis, Trichinella, HEV, Influ A!, Swine Streptococcal sepsis
what diseases are spread by birds?
Psitticosis, Influenza, Cryptococcus, Influ A!!!, Poultry- salmonella, West-
Nile fever
what diseases are associated with water sports?
Leptospirosis, HAV, Giardia, Toxoplasmosis, Mycobacterium marinum/ulcerans, Burkholderia pseudomallei, E. coli
what diseases are water borne?
Campylobacter, Salmonella, VTEC O157, Cryptosporidium
what diseases are food-associated?
Listeria (cow cheese-human), Taenia, Cysticercosis, toxoplasmosis, trichinellosis, Food-associated
yersiniosis, Giardia
What type of bacteria is brucella?
gram negative
aerobic bacillus
**BRUtal - negative
**b for bacillus
How is brucellosis transmitted?
contaminated food (untreated milk / dairy products), direct animal contact (cows, goats, sheep, pigs)
presentation of brucellosis
undulant fever (peaks in evening), myalgia, arthritis, spinal tenderness, hepatosplenomegaly, epididymo-orchitis
MAIN THING- UNDULANT FEVER
(think brucella–>cow–>udder–>UNdulant fever)
diagnosis of brucellosis
Serology - anti-O-polysaccharide antibody. WCC usually normal / neutropenia
treatment of brucellosis
4-6wks doxycycline + streptomycin
what type of virus is rabies?
most common vectors?
rhabdovirus
most common vectors: dogs and bats
presentation of rabies
Prodrome – fever, headache, sore throat b. Acute encephalitis (hyperactive state) c. Migration to CNS (after months – yrs) à fatal encephalitis, hypersalivation,
hydrophobia
what are negri bodies indicative of?
rabies
treatment of rabies
IgG post exposure before the development of symptoms
what causes plague?
what type of bacteria ?
yersinia pestis
gram negative lactose fermenter
presentation of plague
Bubonic plague – flea bites human – Swollen LN (Bubo) – dry gangrene Pneumonic plague – Usually seen during epidemics, person-person spread
treatment of plague
Streptomycin, Doxycycline, Gentamicin, Chloramphenicol (in meningitis)
what bacteria causes leptospirosis?
L. interrogans
what type of bacteria is L. interrogans?
gram negative
obligate
aerobic
motile spirochaete
presentation of leptospirosis
high fever, conjunctival haemorrhages, jaundice, meningism, renal failure,
haemolytic anaemia
buzzword: swimming in tropical waters
treatment of leptospirosis?
amoxicillin, erythromycin, doxycycline or ampicillin
what causes anthrax?
bacillus anthracis
how does anthrax present?
cutaneous: painless round black lesions + rim of oedema
pulmonary: massive lymphadenopathy + mediastinal haemorrhage
**skin + lungs **
treatment of anthrax
doxycycline/ciprofloxacin
what causes lyme disease?
borrelia burgdoferi
what type of bacteria is borrelia bugdoferi?
spirochaete
what transmits lyme disease?
arthropods - ixodes
i.e. ticks
eg on deer during hike
presentation of lyme disease
Early: erythema chronicum migrans (bullseye rash), flu-like
Late persistent: focal neurology, neuropsychiatric, arthritis
treatment of lyme disease
Rx: Doxycycline 2-3wks, (also amoxicillin, cephalosporins)
o If CNS issues, IV ceftriaxone 2-4wks
what causes q fever?
coxiella burnetti
how is q fever transmitted?
via cattle/sheep
how does q fever present?
atypical pneumonia- dry cough, fever, no rash
treatment of q fever
doxycycline
what causes leishmania?
protozoa
L. major or L. tropica
what are the types of leishmania?
- cutaneous
- diffuse cutaneous
- muco-cutaneous
- visceral = kala azar
What causes cutaneous leishamniasis?
presentation?
L. major or L. tropica
Transmission: sandfly bite (South America, Middle East)
o Presentation: Skin ulcer at site of bite –> multiply in dermal macrophages –>heals after
1yr leaving depigmented scar
§ May be single or multiple painless nodules which grow + ulcerate
**key feature is ulceration**
what causes diffuse cutaneous lieshamnia and how does it present?
Pts with immunodeficiency –> nodular skin lesions but do NOT ulcerate
Muco-cutaneous leishamanisasis
Muco-cutaneous, eg: L. braziliensis
o Dermal ulcer (same as cutaneous leishmaniasis) o Months to yrs later à ulcers in mucous membranes of nose and mouth
visceral leishamanisis?
Usually young malnourished child o Abdo discomfort and distension, anorexia, weight loss o Leishmania donovani: invasion of reticuloendothelial system à hepato-splenomegaly,
BM invasion. Later, disfiguring dermal disease (PKDL)
Trypanosomiasis?
Transmitted by Tsetse fly
Causes sleeping disease
most common cause of fever in returning traveller?
malaria
what is torniquet test used for?
dengue fever
gram negatvie rod spread via unpasteurised dairy
brucellosis
presentation of schistosomiasis
Acute infections
Acute symptoms typically only develop in people who travel to endemic areas, as they don’t have any immunity to the worms.
Acute manifestations may include:
- swimmers’ itch
- acute schistosomiasis syndrome (Katayama fever)
fever
urticaria/angioedema
arthralgia/myalgia
cough
diarrhoea
eosinophilia
Chronic infections
Schistosoma haematobium
These worms deposit egg clusters (pseudopapillomas) in the bladder, causing inflammation. The calcification seen on x-ray is actually calcification of the egg clusters, not the bladder itself.
Depending on the site of these pseudopapillomas in the bladder, they can cause an obstructive uropathy and kidney damage.
This typically presents as a ‘swimmer’s itch’ in patients who have recently returned from Africa. Schistosoma haematobium is a risk factor for squamous cell bladder cancer.
Features
frequency
haematuria
bladder calcification
Investigation
for asymptomatic patients serum schistosome antibodies are generally preferred
for symptomatic patients the gold standard for diagnosis is urine or stool microscopy looking for eggs
Management
single oral dose of praziquantel
Schistosoma mansoni and Schistosoma japonicum
These worms mature in the liver and then travel through the portal system to inhabit the distal colon. Their presence in the portal system can lead to progressive hepatomegaly and splenomegaly due to portal vein congestion.
These species can also lead to complications of liver cirrhosis, variceal disease and cor pulmonale.
Schistosoma intercalatum and Schistosoma mekongi
These are less prevalent than the other three forms, but are both attributed to intestinal schistosomiasis.
describe the presentation of toxoplasmosis
immunocompteet
Most infections are asymptomatic. Symptomatic patients usually have a self-limiting infection, often having clinical features resembling infectious mononucleosis (fever, malaise, lymphadenopathy). Other less common manifestations include meningoencephalitis and myocarditis.
Serology is the investigation of choice.
No treatment is usually required unless the patient has a severe infection or is immunosuppressed.
HIV/immunosuppressed patients
Cerebral toxoplasmosis accounts for around 50% of cerebral lesions in patients with HIV
constitutional symptoms, headache, confusion, drowsiness
CT: usually _single or multiple ring-enhancing lesion_s, mass effect may be seen
management: pyrimethamine plus sulphadiazine for at least 6 weeks
Immunosuppressed patients may also develop a chorioretinitis secondary to toxoplasmosis.
