MI: Fever in the Returning Traveller Flashcards

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1
Q

How to take a good travel history

A
  • Where did you go (exactly) + Stopovers
  • Rural vs Urban
  • When did you go + timing of symptoms
  • Why did you go = (VFR - visting friends and relatives, higher risk)
  • Pre-travel vaccines / prophylaxis (malaria)
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2
Q

List some diseases caused by mosquitoes.

A
  • Malaria
  • Elephantiasis
  • Dengue
  • Yellow fever
  • West Nile virus
  • Zika virus
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3
Q

What is the vector for malaria?

A

Anopheles mosquito (female)

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4
Q

What are the five species of Plasmodium.

A
  • Plasmodium falciparum (75%)
  • Plasmodium vivax (20%)
  • Plasmodium ovale
  • Plasmodium malariae
  • Plasmodium knowlesi
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5
Q

Outline the life cycle of Plasmodium within humans.

A
  • Mosiquito bite infects humans with sporozoites
  • Within humans there is an exoerythrocytic stage (liver) and an erythrocytic stage
  • It replicates within liver and can remain dormant for years (vivax and ovale [hypnozoites])
  • It then infects erythrocytes and asexually reproduces, the ruptures to release the parasite
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6
Q

Why does falciparum cause greatest mortality?

A
  • Invades RBCs of all stages
  • May be drug resistant
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7
Q

What is the incubation time for malaria

A

Up to 1 month for falciparum

Longer for others

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8
Q

Which malaria types is this?

A

Falciparum

  • Little headphones
  • More than one in each cell
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9
Q

List the components of malaria prevention.

A
  • Awareness of risk
  • Bite prevention - repellants / nets
  • Chemoprophylaxis eg. malarone
  • Diagnose promptly and treat without delay
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10
Q

Describe the clinical features of malaria.

A
  • Fevers - cyclical or continuous with spikes
  • Malaria paroxysms - chills, high fever, sweats

Malarae - 3 days
Others - 2 days

Usually 10-15 days after bite
Vivax - much longer - hypnozoite stage (liver)

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11
Q

What is this?

A

Schizont
A malaria parasite which has matured and contains mainy merozoites
Indicative of severe malaria

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12
Q

What is the definition of severe malaria?
List some clinical features.

A
  • High parasitaemia - >2% (low transmission areas) or >5% (high transmission areas)
  • OR visualised schizont

Organ failures

  • Altered consciousness
  • Respiratory distress or ARDS
  • Hypoglycaemia
  • Metabolic acidosis
  • Circulatory collapse
  • Renal failure, haemoglobinuria (blackwater fever)
  • Hepatic failure
  • Coagulopathy +/- DIC
  • Severe anaemia or massive intravascular haemolysis
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13
Q

What is the main investigation for malaria?

A

Perform 3 thick and thin blood films

  • Thick - screening for parasites (sensitive)
  • Thin - identifying the species and quantifying the parasite (proportion of red cells that have been parasitised)
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14
Q

Which stain would you use in malaria blood film?

A

Field’s or Giemsa stain

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15
Q

List two examples of malaria rapid antigen tests.

A

Paracheck-PF (plasmodial HRP-II)

OptiMAL-IT (parasite LDH)

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16
Q

Outline the treatment options for non-falciparum malaria.

A

Chloroquine + primaquine

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17
Q

What must you do before giving someone primaquine?

A

Screen for G6PD deficiency as primaquine can cause extensive haemolysis

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18
Q

What are the complications of non-falciparum malaria?

A

Very rare but there are reports of splenic rupture

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19
Q

What counts as ‘mild’ falciparum malaria?

A
  • Not vomiting
  • Parasitaemia < 2 %
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20
Q

Outline the treatment options for mild falciparum malaria.

A
  • First line - artemisinin-based combined therapy (ACT) e.g. Riamet (artemether-lumefantrine)
  • Malarone (atovaquone and proguanil)
  • Quinine and doxycycline
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21
Q

Outline the management of severe falciparum malaria.

A
  • ABCDEFG approch
  • Correct hypoglycaemia
  • Cautious hydration
  • Organ support if necessary
  • IV artesunate 1st line
    (SEAQUMAT trial)
  • Daily parasitaemia monitoring
  • Follow on with oral antimalarials
22
Q

Why is quinine not first-line in severe falciparum malaria?

A

Extensive side effects:

  • Cinchonism: tinnitus, dizziness, nausea and vomiting
  • Arrhythmias
  • Hyperinsulinaemia
23
Q

What is the vector for dengue?

A

Aedes mosquito

24
Q

What typs of virus is the dengue virus?

A

RNA virus with 4 main serotypes

25
Q

Outline the clinical features of dengue.

A

Febrile phase lasts for around 4 days

26
Q

What are the complications of dengue? In which circumstances does this tend to occur?

A

Dengue haemorrhagic fever and dengue shock - occurs in individuals who have previously been infected with a different dengue serotype and are then infected by another serotype

27
Q

List some diagnostic tests for dengue.

A
  • Blood/urine PCR
  • Serology (IgM 5-7 days)
  • RDT
28
Q

How is dengue treated?

A

Identify those at risk of severe disease

Supportive

29
Q

What is the term used to describe a high temperature with a relatively normal heart rate? List some causes.

A

Sphygmothermic dissociation

  • typhoid,
  • brucellosis,
  • yellow fever,
  • tularaemia
30
Q

What is typhoid fever caused by?

A

Salmonella typhi and paratyphi

31
Q

What type of organism is Salmonella typhi?

A

Gram-negative rod

32
Q

Outline the clinical features of typhoid fever.

A
  • High prolonged fever (no rigors)
  • Classical ‘pea green diarrhoea’
  • Headache
  • Relative bradycardia (sphygmothermic dissociation)
  • Rose spots (rare)
  • Constipation
  • Hepatosplenomegaly
  • Dry cough
33
Q

Describe the stages of typhoid?

A
  1. Constipation, gradual rise in body temperature, relative bradycardia
  2. Pesistant fever, hepatosplenomegaly, rose spots
  3. GI bleeding, sepsis
34
Q

What is the incubation period of typhoid?

A

1-2 weeks

35
Q

List some complications of untreated typhoid.

A
  • GI bleeding - congested Peyers patches
  • Perforation
  • Septicaemia
  • Encephalopathy
36
Q

How is typhoid diagnosed?

A
  • Cultures - stool, blood, bone marrow (rarely)
  • Serology

Widel (RDT) - cheap but false positives

37
Q

What is the treatment for Typhoid?

A

Oral rehydration solution

Antibiotics

  • Uncomplicated empirical - azithromycin
  • Complicated - IV ceftriaxone
38
Q

What is mononucleosis caused by?

A

EBV or CMV

39
Q

What is a characteristic clinical feature of mononucleosis?

A

Tonsillar enlargement with exudates

40
Q

List some investigations for mononucleosis.

A
  • Monospot
  • IgM EBV/CMV

NOTE: always consider HIV

41
Q

What is a characteristic microscopic feature of mononucleosis?

A

Atypical lymphocytes

42
Q

What is leptospirosis and how is it spread?

A

Infection caused by Leptospira (spirochetes)

Commonly spread by rodents - associated with sewers and dirty water contaminated by rodent urine

43
Q

Describe the clinical presentation of leptospirosis

A

Weil’s - jaundice, renal failure, haemorrhage

Causes positive agglutination test - vascular

44
Q

How is leptospirosis diagnosed and treated?

A

Diagnosis

  • PCR serum/urine/CSF
  • Serology - IgM ELISA

Treatment

  • Doxycycline
  • Ceftriaxone
  • Penicillin
45
Q

What is Lyme disease and how is it spread?

A

Infection by Borrelia
Spread by Ixodes ticks

46
Q

Describe the clinical presentation of lyme disease.

A
47
Q

How is Lyme disease diagnosed and treated?

A

Diagnosis

  • Clinical
  • ELISA
  • PCR blood/CSF (imperfect)

Treatment

  • Doxycyline
  • Amoxicillin
  • Ceftriaxone in neuroborreliosis
48
Q

What is lymphogranuloma venereum (LGV)?

A

STD caused by Chlamydia trachomatis (invasive serovars)

Sexual transmission then travels from innoculation site into lymphatic system

49
Q

Describe the clinical presenation of LGV

A
50
Q

How is LGV diagnosed and treated?

A

Diagnosis

  • Serology
  • Direct fluorscent antibody test
  • PCR infected area/pus

Treatment

  • Drainage of buboes/abscesses
  • Antibiotics - doxycycline (1st), azithromycin (2nd)

(Contact tracing)