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PBL SEMINAR . FEVER IN A RETURNED TRAVELLER. OUR PATIENT CASE. Our patient is Jenny Randall , a 23 y.o. female student who presents to her local doctor with cough and fever having recently returned from a 3 week holiday. IMPORTANT. What’s common is common The diagnosis is

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pbl seminar

PBL SEMINAR

FEVER IN A RETURNED TRAVELLER

our patient case

OUR PATIENT CASE

Our patient is Jenny Randall, a 23 y.o. female student who presents to her local doctor with cough and fever having recently returned from a 3 week holiday

important
IMPORTANT
  • What’s common is common
  • The diagnosis is

MALARIA MALARIAMALARIA

until proven otherwise.

travel history chocolates
Travel History: CHOCOLATES
  • Country of birth
  • Housing
  • Occupation
  • Contacts
  • Other drugs
  • Leisure time
  • Animals
  • Travel
  • Eating and Drinking
  • Sexual history
slide7

HOPC

  • Travel History: CHOCOLATES
travel history chocolates1
Travel History: CHOCOLATES
  • Country of birth
  • Housing
  • Occupation
  • Contacts
  • Other drugs
  • Leisure time
  • Animals
  • Travel
  • Eating and Drinking
  • Sexual history
patient history
Patient History
  • Ms Jenny Randall, a previously well 23 year old medical student, presents to her local doctor with a cough and fever.
  • Jenny recently returned from a 3 week trip to Thailand, Cambodia and Vietnam.
  • In the 3 days leading up to her presentation at the clinic, Jenny experienced the following symptoms:
  • fevers
  • rigours (what makes them rigours?)
  • myalgia
  • mild non-productive cough
  • malaise
  • mild headache
  • No relevant past medical history
  • Family history of CVD- father died of AMI at 58
  • Medications
  • OCP
  • Paracetamol for fever
  • NKDA
  • Social History
  • Smokes 10-20 cigarettes/day,
  • no ETOH,
  • one regular and one new sexual partner in past 6 months, uses condoms 100 % of the time
travel specific questions
TRAVEL SPECIFIC QUESTIONS
  • Born in Australia
  • Travelled to Vietnam via Thailand and Cambodia for 3 weeks during the hot/rainy season
  • Returned for two weeks before becoming unwell
  • Stayed in budget, sometimes crowded accomodation throughout recent travel
  • Exposure to water, mosquitos, flies
  • Recent contact has a 'cold'
  • Took prophylactic Doxycycline for one week before discontinuing
  • Had pre-travel Typhoid and HepA immunisation and previous HepB immunisation
  • Often prepared own food, no GI symptoms
red flag
!~RED FLAG~!
  • What symptom stands out as a red flag?
  • RIGORS!
  • What are rigors?
  • Episodes of uncontrollable shakes with or without teeth chattering lasting 15 minutes or more.
  • What causes them?
  • Bacterial sepsis e.g. From biliary sepsis or pyelonephritis, visceral abscesses, pneumonia
  • Malaria
  • Influenza
  • Why can we not ignore rigors?
  • Causes can be immediately life threatening and are treatable!!
pyrexia of unknown origin puo
Pyrexia of Unknown Origin (PUO)

Definition: In adults: T>38.3 for>3 weeks with no known origin despite appropriate Ix.

  • Approach: - identify cause
    • Detailed history and regular examination
    • Confirm temperature objectively, ?admission, ?physiological with circadian pattern
    • Guide investigation based on initial test results
      • Blind investigation may be necessary
        • FBE, ESR, U+E, CRP, LFT, ANA, RhFx, TFT
        • Regular cultures (any fluid – blood, sputum, urine, stool, CSF)
        • CXR, CTA, echo
        • CT, IVP, MRI, PET
    • Treatment – ideally symptomatic prior to Dx
      • Empirical A/B therapy may mask infectious Dx
      • Empirical steroid therapy may mask inflammatory response w/o treating cause
    • Undiagnosable PUO – Sx usually spontaneously resolve, good prognosis
    • Excluded from case differential
special points for an id ex
Special points for an ID Ex
  • Gen Inspection
    • Room
      • Sputum cup
      • O2
      • IV – anything running
      • Drain tube
      • Catheter – check urine
      • Temp chart
    • Patient
      • Distress (RR, diaphoretic, conscious state)
      • Rash – blanching/non-
      • Track marks IVDU
      • Any lines – sepsis?
      • Weight loss – chronic illness
  • Hands
    • Janeway
    • Splinters
    • Osler’s nodes
    • Erythema
    • Track marks
    • Bruising, petechiae
    • Phlebitis
    • Arthropathy, raynauds - CTD
  • Face
    • Eyes – Roth spots (fundoscopy), pallor, jaundice (BW fever)
    • Mouth – hygeine, ginigivitis, abscess
    • Neck – lymphadenopathy
  • Chest
    • Crepitations, consolidation
  • Praecordium
    • New murmur
  • Abdomen
    • Tenderness? – localised?
    • Organomegaly
    • rashes
  • Genitourinary
    • Stool sample
    • Urinalysis
    • Discharge
    • orchitis
  • Legs
    • Rash
    • ulcers
on examination
On examination:
  • Chest clear. Full CVS, respiratory and abdominal examinations NAD
  • No rashes, joints appeared normal.
  • Vitals
  • HR 72
  • BP 120/60
  • RR 16
  • T 36.2

With these history and examination findings, Jenny was sent home with a suspected viral URTI.

The next day, Jenny re-presents with continuing fevers, having taken her own temperature measuring 36.9 that morning.

the pattern of fever
The Pattern of Fever

Typical malarial fever patterns

- not necessarily useful diagnostically

  • Timeline of Jenny’s ‘fever’
  • Day 1 – onset of disease – T?
  • Day 4 – visit doctor – 36.2
  • Day 5 – 10am – 36.9
  • Day 5 – afternoon – 36.9
  • Day 5 – night – 38.5
  • *NO FEVER RECORDED until day 5*
    • Doesn't always follow typical pattern in all patients
      • Typically – may be afebrile for days
      • Atypically (common) – may be febrile or afebrile the entire length of the disease
    • Accurate recording procedure
    • Hx of fever given by reliable witness should not be ignored even if it is recorded as afebrile.
slide19
DDx!!
  • Malaria (parasite)
  • Typhoid (bacteria)
  • Dengue fever (virus)
  • Hepatitis A
        • We want to rule these out before progressing to investigate for other conditions common in returned travellers.

THE BIG FOUR

other infections to be considered in returned travellers
Other Infections To Be Considered in Returned Travellers

Developing Countries

  • Bacterial sepsis other than typhoid (such as meningococcal sepsis, sepsis from abdominal organ perforation, pneumonia, urosepsis)
  • TB
  • Dysentry
  • Schistosomiasis
  • Amoebic liver abscess
  • Tick typhus
  • Viral haemorrhagic fevers other

than Dengue

World Wide

  • Influenza
  • Atypical pneumonia
  • URTI/viral infection
  • STI including acute HIV infection
  • UTI
  • Pyelonephritis
slide26

BASIC PATHOPHYS.

STRAINS OF MALARIA

the malarial cycle
THE MALARIAL CYCLE

1) MOSQUITO VECTOR

2) EXTRA-ERYTHROCYTIC

3) ERYTHROCYTIC PHASE

slide28

Malarial Immunology

  • Immunological evasion by Malaria –
    • Malaria avoids WBCs by invading the body’s own cells and using these “self” antigens as a mask for infection. The body only has a chance of reacting during a lysis cycle when the parasites are free in the blood, though time is limited.
    • Splenic removal is the only effective method of removal. Protozoalaggregation in small capillaries counters this – causes complications
jenny s ix findings
Jenny’s Ix Findings
  • FBE
    • HB 110, WCC 7.0, Plt 110
    • HB 100, WCC 7.3, Plt 90
    • HB 90, WCC 7.2, Plt 96
    • HB 95, WCC 7.2, Plt 115
  • UECs
    • Na 140, K 4.0, Ur 7.0, Cr 110
  • LFTs
    • Mildly elevated ALT and bilirubin,otherwise normal
  • Atypical pneumonia - Legionella, Chlamydia species, Mycoplasmapneumoniae, Pneumocystisjiroveci serology - pending
  • CXR - clear
  • Malarial Thick and Thin Film
    • Negative
    • Positive for plasmodium falciparum, parasite count 0.2%
    • parasite count 0.1%
    • parasite count 0%
  • Hep A serology - Total Ab positive, IgMnegative
  • Hep B serology - Surface Antibody positive, surface negative
  • Arbovirus (dengue) serology - negative
  • HIV serology - negative
  • Pregnancy Test - negative
malarial thick and thin blood films
Malarial Thick and Thin Blood Films
  • 3 thick and thin smears 12-24hrs apart should be obtained
  • Highest yield of peripheral parasites occurs during or soon after a fever spike; however smears should not be delayed to await a fever spike.
  • Thin Films - qualitative (speciation)
  • Thick Films - quantitative (parasite count)
slide33

Determining types of malaria

Histological Differences

slides
Slides
  • Plasmodium falciparum
  • P vivax
  • P ovale
  • P malariae
  • Normal
incidence
Incidence
  • 3 billion people (1/2 world’s population) living in areas at risk
  • 1-2 million deaths per year
  • 5th most common cause of death from infection worldwide
  • 2nd most common cause of death from infection in Africa
where malaria occurs
Where malaria occurs

Most countries in the tropics

107 countries

transmission patterns
Transmission patterns
  • Social and Economic Toll
  • Cost to individuals
  • Cost to government
risk factors for travellers
Risk factors for travellers
  • Destination
  • Season
  • Accommodation
  • Activities
  • Failure to carry out protective measures
  • Taking counterfeit or substandard anti-malarials

Who is the most vulnerable?

  • Young children
  • Pregnant women
  • Immunocompromised individuals
  • Immigrants from endemic areas living in non-endemic areas
treatment
Treatment
  • There are many different types of antimalarialdrugs
  • The decision of which to use is dependent on the setting of treatment:
      • ?Remote region - no infusion or injections available
      • The resistances of the parasite
      • Life-cycle of the parasite
traditional thinking
Traditional thinking
  • Traditionally it has been taught that if the parasite is sensitive to chloroquine, then this will be used
  • And if the parasite is resistant to chloroquine, a quinine salt is administered
  • However these therapies are largely outdated, and nearly all P. falciparum are resistant to chloroquine.
  • It is useful to know this however, as treatment of malaria is very dependant on the medical resources available, and as the newer, more effective drugs are also more expensive, in some areas of the world old therapies must still be relied upon.
current therapy in australia uncomplicated malaria
Current therapy in Australia- Uncomplicated Malaria
  • For uncomplicated Malarial infection, an artemesinin derivative, typically artemether, combined with lumefantrine (sold as Riamet®)
      • Administer 4 tablets/12 hours for 6 doses.
  • Uncomplicated malarial infection can progress to a more severe form, defined by:
  • •Altered conscious state
  • •Jaundice
  • •Oliguria
  • •Parasite count>2% of RBCs
  • •Acidotic
current therapy 2 severe malaria
Current Therapy (2) - Severe Malaria

Treatment alters slightly in severe malaria, and the primary treatment is a different artemesinin derivative

  • IV Artesunate, 2.4mg/kg on admission and given every 12 hours until oral therapy is possible
  • Use artemether+lumefantrine when infection is less severe
  • It is also essential to carefully monitor and correct if necessary the patient’s:
      • fluid levels,
      • blood glucose
      • urine output
  • •Daily parasite counts, platelets, U&E's and LFT's should also be taken
prophylaxis
Prophylaxis
  • Prophylactic therapy is typically chosen based on the area the individual may be travelling to.
  • •In general terms, due to the high levels of chloroquine resistance, Atovaquone+proguanil (Adult: 250+100mg PO) is used, 1-2 days before travel, and 7 days after.
  • •Doxycycline (100mg daily) is also used; 2 days before travel, contuining until 4 weeks after.
  • –SE: Oesophagitis, photosensitivity, vaginal thrush
  • •Mefloquine (250mg weekly) is not used in Australia, yet is used widely around the world.
slide53

Complications of Malaria

CNS: cerebral malaria

Renal: blackwater fever: haemoglobinuria + haemolysis + renal failure, uraemia (acute tubular necrosis)

Blood: severe anaemia (haemolysis, dyserythropoiesis, splenomegaly with sequestration and folate depletion)

Respiratory: acute respiratory distress syndrome (ARDS)

Metabolic: hyperglycaemia, metabolic acidosis

GI: diarrhoea, jaundice, splenic rupture  haemorrhage

Other: shock/hypotension (especially with secondary bacterial infection), hyperpyrexia

complications of malaria
Complications of Malaria
  • CNS: cerebral malaria
  • Renal: blackwater fever: haemoglobinuria + haemolysis + renal failure, uraemia (acute tubular necrosis)
  • Blood: severe anaemia (haemolysis, dyserythropoiesis, splenomegaly with sequestration and folate depletion)
  • Respiratory: non-cardiogenic pulmonary oedema/ acute respiratory distress syndrome (ARDS)
  • Metabolic: hyperglycaemia, metabolic acidosis
  • GI: diarrhoea, jaundice, splenic rupture  haemorrhage
  • Other: shock/hypotension (especially with secondary bacterial infection), hyperpyrexia
slide55
Cerebral Malaria

- recognised by a decreased conscious state not a headache

- causes 80% of deaths from Malaria and will kill 15- 20% of the people who have it even with treatment

Non-cardiogenic Pulmonary Oedema

- caused by overhydration, increased permeability of pulmonary vessels in response to the infection or by the clogging of pulmonary microcirculation by infected red cells

- 50% mortality

Renal Failure

- caused by dehydration, increased blood viscosity and the products of haemolysis

- adequate rehydration needed

prognosis
Prognosis

Criteria for a poor prognosis:

  • < 3 years old
  • Pregnancy
  • Fits
  • Comas
  • No corneal reflex
  • Papilloedema
  • Pulmonary oedema/ARDS
  • HCO3- <15mmol/L
  • Plasma or CSF lactate >5mmol/L
  • Hyperparasitaemia (>5%RBCs or 250,000/mL)
  • Hb <5g/L
  • Creatinine >265mmol/L
  • Malaria pigment >5% neutrophils
  • Complicating infection
  • DIC
  • >20% of parasites are mature trophozoites or shizonts
the main criteria for poor prognosis
The main criteria for poor prognosis:

The species of Malaria:

P. Falciparum

The number of parasites:

>5% of RBCs

traveller s advice
Traveller’s Advice
  • Risk assessment
  • Administer vaccinations
  • Malaria prevention
  • Essential preventive behaviours
slide60
Risk assessment:
    • Itinerary (country / regions / dates of travel)‏
    • Urban / rural
    • Age
    • Past vaccination Hx
    • Comorbidities
    • Current Medications
    • Pregnancy status
    • Allergies
    • Purpose of trip
    • Risk exposures (blood, body fluids, extreme sports, outdoors)‏
    • Types of accomodation
    • Travel insurance
    • Level of aversion to risk
slide61
Administer Immunisations
    • Routine vaccinations
    • Travel vaccinations
slide63
Essential preventive behaviours
    • Food and water safety
    • Protection against STDs (always use condom)
    • Motor vehicle safety
    • Personal safety (appropriate dress, crime, recreational activities, local customs, etc.)
    • Altitude / motion sickness / jet-lag
objectives
OBJECTIVES

RED FLAGS

  • Rigors = hospital admission

HOW TO TAKE A HISTORY IN A RETURNED TRAVELLER

  • How to take/interpret a fever

MALARIA

  • Diagnosis
  • Pathophysiology
  • Management

COUNSELLING A PROSPECTIVE TRAVELLER