Travel medicine + Diarrhoea Flashcards
(151 cards)
1
Q
How many kids <5 die from diarrhoea each year
A
500,000
Most in SSA and india
2
Q
How often do kids have diarrhoea each year
A
3 episodes per year
Peak at around 6-12 months (stop breast feeding and start crawling)
3
Q
Name 3 risk factors for diarrhoea in children
A
Lack of breastfeeding 10x higher risk of mortality in <6m- Most important (and very cheap to fix)
Age: < 5 years, especially 6 18 months
Malnutrition
Immunosuppression
Measles
No immunizations
Lack of safe drinking water, sanitation and hygiene
4
Q
3 categories of pathogens commonly causing diarrhoea in kids
A
Virus
rotavirus, norovirus - Top 2
[astrovirus , enteric adenovirus]
Bacteria
Shigella , Salmonella,
Campylobacter , diarrheagenic E. coli ,
Vibrio, Yersinia , Aeromonas ,
Plesiomonas
Parasites
Giardia , Crysptosporidum ,
Microsporidium , Cyclospora , Isospora ,
E. histolytica
5
Q
What test is sensitive for bacterial diarrhoea
A
> 50 fecal leucocytes
-This indicates inflammation = likely bacterial
Key test in resource-poor places
6
Q
Osmotic vs secretory
A
Secretory - has a toxin -> pulls water and electrolytes out
Osmostic - eg rotavirus
7
Q
The most common cause of diarrhoea in kids <1 and globally <5 cause of death
A
rotavirus - 30% of deaths from diarrhoea
8
Q
Types of E coli
A
ETEC - Enterotoxigenic E. coli
EPEC - Enteropathogenic E. coli
EIEC Enteroinvasive E. coli
STEC or EHEC Shigatoxin producing or EEnterohemorrhagic E. coli
EAEC - enteroaggregative E coli
9
Q
Which e coli common to present with prolonged / chronic diarrhoea in kids
A
EPEC - Enteropatogenic E. coli
[E Paediatric/Prolonged]
10
Q
Which e coli most common in travellers
A
ETEC - High volume watery diarrhoea
Entrotoxigenic E. coli (toxin similar to cholera toxin)
[E Traveller]
11
Q
Which E coli is common in HIV and causes a biofilm
A
EAEC - Enteroaggregative E. coli
-As adheres can have prolonged infection
[Aggregates on itself and makes biofilm]
12
Q
Which E coli produces shiga-like toxin -> bloody dysentery
A
EHEC (also called STEC - Shiga toxin-producing E Coli)
Especially 0157 strain
->HUS 10%
[oH HEC its the bad one]
13
Q
Which are key pathogens for acute watery vs prolonged vs bloody vs dehydrating diarrhoea
A
Acute watery diarrhea :
rotavirus, norovirus, Cryptosporidium , ETEC, EPEC, Shigella , Campylobacter , Salmonella
Prolonged or persistent diarrhea :
EAEC, EPEC, parasites (coccidia
Bloodydiarrhea :
Shigella , Salmonella,
Campylobacter , STEC
Dehydrating diarrhea : Most important
rotavirus, ETEC, Cholera
[REC]
14
Q
Good cheap test for shiga-like toxin
A
Latex agglutination test
15
Q
Lots of coloisation in stool samples. How do you differentiate between colonisation and infective cause
A
PCR quantification (number of copies of DNA)
16
Q
3 critical signs of dehydration
A
Thirst
Sensorium: irritable or comatose
Skin turgor: slow, very slow
-Best to do on abdo
[Sunken eyes, dry membranes, absent tears]
17
Q
Mild vs mod vs severe dehydration in kids? Rx
A
A - Education and ORS
B - needs 100ml/kg in 6 hours
C - IV 20ml/kg if shocked, or 100ml/kg Oral in 6hrs
18
Q
Key 3 measurements dehydration
A
Weight loss, blood pressure, urine output
19
Q
Why do you not bolus Ringers lactate / polyelectrolyte solutions
A
Cant bolus stuff with K+ in
20
Q
Key supplement for kids who have diarrhoea?
A
Zinc if >6m
- reduces symptoms and length
- prevents diarrhoea
21
Q
What would make you want to use Abx in childhood diarrhoea
A
Fecel leucocytes > 50
Fever + bloody diarrhoea
22
Q
Main causes of dehydrating diarrhoea
A
Rota, ETEC, Cholera
23
Q
Explosive, watery (5-10 episodes day ), dehydrating diarrhea
Vomiting
Fever
Most likely? Key age group?
A
Rotavirus at 3-24months
[almost 100% have antibodies by 5 years]
[Norovirus second]
24
Q
Rotavirus Dx?
A
Clinical usually
Rapid test Eg Latex agglutination / ICT
PCR
-Used if severe / outbreak / immunocompromised…
[Testing usually to prove its a viral illness -> avoid Abx]
25
Why rotavirus rare <3m
IgA from breast milk
26
rotavirus prevention
oral vaccine
Water and sanitation
27
Differentiate rota and noro in children clinically
Duration
Noro - <3 days
Rota - 5-8 days and slightly more severe
Both more in winter but:
-Rotavirus almost no cases in summer
-Noro all year round
28
How long excrete norovirus ? Issues with this?
several weeks
False positive tests down the line
Remain infectious
29
Most common cause of foodborne gastroenteritis outbreaks worldwide? - what is the classic foodstuff
Norovirus
Oysters
30
Why norovirus outbreaks in hospitals
Survive chlorhexidine / alcohol
31
Why norovirus outbreaks in hospitals
Survive chlorhexidine/alcohol
32
2 viruses which are similar to rotavirus but less severe? Diagnosis of these?
Adenovirus
astrovirus
Stool ELISA
33
What is genus shigella actually part of ?
E coli
34
Which shigella causes epidemics? Which common in India? Which in the industrialised world ? Which is most common? Which has most resistance? Most severe?
- S dysenteriae - epidemics and severe
- S boydii - india
- S sonnei - industrialised and most resistance
- S Flexneri - most common 70% of cases
35
What 2 dietary supplements are shown to reduce the incidence of dysentery
- Zinc
- Vit A
36
What produces shiga toxin? What complication may develop?
- Sh dysenteriae serotype 1
[Also produces a neuro toxin -> CNS]
HUS in around 15% of cases
37
Shigella incubation
1-5 days
[not less than 24hrs]
38
Shigella dx?
- Stool culture - need 2
- Fecal leukocytes helpful
39
Shigella rx? Second line?
- Most ok with ORS
- Ciprofloxacin (or another quinolone first line)
- Azithromycin
40
Shigella prevention
- Hygiene and sanitation
- Especially hand washing when preparing food
41
Only living reservoir for shigella and cholera?
Humans
[cholera - also water..copepods]
42
2 parts of cholera toxin and effect
- B - Binds to epithelial cells and allows entry of A
- A - increases cAMP and causes secretion of chloride by crypt cells -> diarrhoea
43
Cholera shape and stain
Gram -ve comma shaped bacilli with flagella
44
Which 2 cholera sero groups cause infection? Incubation?
- 01 and 0139
- Most outbreaks are 01 form
14hrs to 5 days
45
Rx of cholera ? Which abx can be used in severe cases?? What do Abx do?
- Fluid therapy
- Azithro / doxy
Don't improve mortality
-Reduce volume of stools and transmission
-> require less resource for management
46
Cholera control strategies
- Early detection and isolation
- Contact tracing of household
- Longer term - improve water supply
- Oral cholera vaccines - Variable protection (Shanchol)
47
How to make ORS if you dont have it
1/2 teaspoon of salt
6 tea spoons sugar
1L water
48
Which group have high rates of shigella
Men who have sex with men
49
When not cipro for shigella
Asia (commonly resistant)
-> ceftriaxone
50
Cholera key implicated foodstuff for infection
shellfish and crabs
51
Cholera key implicated foodstuff for infection
shellfish and crabs
52
Obvious risk factors for cholera such as age, malnutrition but what blood type and which infection also implicated ?
Blood group O
H pylori
reduced gastric acidity
53
What factors affect cholera in water ? Specifically where in water does cholera live?
Temp, pH, salinity, sunlight - eg el nino
Grows in alkaline conditions
Lives next to phytoplankton - uses this for nitrogen
54
Which medium required for isolation of cholera
TCBS
Thiosulphate-citrate bile salts-sugar agar
green coloured medium with shiny yellow cholera colonies
55
2 main serotypes of 01 cholera
El tor
-Survives better in environment and causes less severe disease
Classical biotypes
-Endemic in Bangladesh only
more severe
56
Most sensitive clinical finding correlating with severe dehydration eg cholera
Character of radial pulse
57
What extra findings in Kids with cholera
Fever seizures and coma more predominant
HypoK, HypoNa, HypoGly more common
58
When IV fluid choice in cholera? over how long should you initially give resus fluid
Severe dehydration
Not tolerating PO
Ringer's lactate
Rehydrate over 4 hours ~100ml/kg
59
Which country has 90% of cholera at the minute
yemen
60
What causes typhoid? what is it called when you develop septicaemia?
Salmonella enterica serovar typhi (salmonella typhi)
Gram negative bacilli
Enteric fever
61
Typhoid incubation? Common sx? Complications?
3 days - 2 weeks depending on inoculation load
High fever, variable systemic unwell, often consitpation
Rose spots
Paradoxical normal HR / brady despite the fever
GI bleeding, perf, pneumonitis, hepatitis - usually after 3 weeks
62
Typhoid dx? if poor facilities for this?
Blood culture
Widal agglutination test - measures antibodies to somatic (O) and flagellar (H) antigens
- not sensitive or specific
[Stool culture / bile/bone marrow aspirate]
63
Who gets big bilirubin rise in typhoid?
G6PD
64
Typhoid / paratyphoid rx? 2nd line?
-Cipro 1st line
[Azithro/Ceftriaxone - especially if high MDR area Eg India Pakistan]
Meropenem if really sick
65
Chronic typhoid carriers tend to have salmonella living where? Important long term risk?]Rx?
Gall bladder -may cause chronic cholecystitis/gallstone disease
-Risk of biliary Ca
Cipro - excreted in bile [+ high concentrations in the bowel]
66
Which salmonella has a vaccine? significance?
S typhi
Paratyphi causes 50% of infections in asia
67
Typhoid from where might end up with meningoencephalitis
Indonesia/India
68
Typhoid bloods
Leukopenia
Eosinopenia
Mild derranged LFTs
69
Typhoid resistance to what means you cant Rx with cipro
Nalidixic acid
70
Typhoid then 3 weeks later pain in RLQ what are you worried about
Ileal perf
71
Most effective typhoid vaccine
Conjugate vaccine
72
Shigella classic presentation
Classical presentation: watery diarrhoea for 1-2 days, then visible blood - but not massive volumes of stool
[In reality - only 40% are actually bloody]
73
Shigella transmission?
Direct contact faecal oral
-Often from mum
Very low infectious dose - 200 bacteria only
74
Key risk factors for severe shigella
Infants and adults > 50y
Children who are not breastfed
Children recovering from measles
Malnourished children and adults
History of seizures - 10% have seizures
75
Key complication of campylobacter
Guillain barre
76
2 main species of campylobacter
C Jejuni
C Coli
77
Campylobacter reservoir
Poultry
[Pig]
78
Campylobacter vs Shigella usual age in kids
Campy - first year of life
Shigella - Second year
79
Campylobacter Rx
Azithromycin
80
Campylobacter Dx
Stool cultures at 42 degrees
81
Diarrhoea then 4 days later reduced urine output and pale looking what are we worried about? key features ?
HUS
Thrombocytopenia
Anaemia
Renal failure
82
If the child presents with bloody diarrhea without fever key dx? what should you do?
STEC/EHEC (same thing)
NOT prescribe abx
If STEC/EHEC -> likely to augmented toxin production
83
Case 1: 10 month old girl with 1 day of diarrhea with blood, 3 stools/day and fever.
Case 2: 3 year old boy with 2 days of diarrhea with mucus and blood, 7 stools/day, abdominal pain and fever.
Case 3: 6 year old boy with 4 days of diarrhea with gross blood, 6 stools/day, intense abdominal pain and no fever.
1 - Campylobacter as <1year
2 - Shigella
3 - STEC (bloody diarrhoea and no fever)
84
Most common cause of fever in returned travller
Malaria - P falciparum most likely
85
Fresh water exposure risk of (2)?
Leptospirosis, Schistosomiasis
86
Exposure to rodents risk of? name 3
Hantavirus,
Lassa fever and other hemorrhagic fevers,
plague,
rat-bite-fever,
murine typhus
87
3 risks with unpasturised dairy products
Brucellosis, salmonellosis, tuberculosis, Q fever, listeriosis
88
Sea food and fish, raw or undercooked risk of?
Clonorchiasis, paragonimiasis, Vibrio, hepatitis A, gnathostomiasis, adenocephalus pacificus/dibothriocephalus latus
89
Raw meat risk of?
Trichinellosis, salmonellosis, E.coli O157, campylobacteriosis, toxoplasmosis, gnathostomiasis
90
Raw vegetables, aquatic plants (watercress), snails risk of?
Fasciolasis, fasciolepsiasis, angiostrongylosis
91
Classic examples of a biphasic (saddleback) fever?
Dengue, YF, leptospirosis
92
What do these signs mean? (rule in of)
Eschar:
* Chancre:
* Rose spot:
* Symmetrical arthritis of small joint:
* Conjunctival suffusion:
* Rash and conjonctivitis:
* Rash « White island on a red sea »:
* Anosmia:
Eschar: Rickettsiosis
* Chancre: syphilis, trypanosomiasis
* Rose spot: Enteric fever
* Symmetrical arthritis of small joint: Chikungunya
* Conjunctival suffusion: leptospirosis
* Rash and conjonctivitis: Zika
* Rash « White island on a red sea »: Dengue
* Anosmia: COVID-19
93
Trip in India, Nepal, Pakistan, Bengladesh
High fever, abdominal pain, relative bradycardia = ?
Enteric fever
94
Fresh water exposure in Malawi Lake
Fever, eosinophilia, hepatomegaly
Katayama fever
95
Mosquito bite in urban areas in tropical country
Fever, headache, myalgia, retroorbital pain, rash, thrombocytopenia
Dengue
96
Rafting, Thailand
Fever, myalgia, conjunctival suffusion icterus, rash
leptospira interrogans
97
Forest in central Europe
Fever, ALC, paralysis
Tic bite encephalitis
98
Back from a trip to subsaharian Africa Amazon, non vaccinated
Hemorragic fever, icterus, kidney failure, proteinuria
Yellow fever
99
Trip in south Africa, safari
Fever, eschars
African tick-bite fever (Rickettsia africae)
100
Name 3 risk factors for travellers diarrhoea
Daily use of a proton pump inhibitor
Low-budget or adventure travel
O blood type
Travel from an industrialized country to a developing/tropical
Age
* Being a toddler or adolescent
Lack of dietary discretion
No previous travel to a developing region
101
Localised infection with fever - which organ systems are usually bacterial
Gastrointestinal: 80% bacterial
Genitourinary : >90% bacterial
Cutaneous : >90% bacterial
102
Undifferentiated fever in Asia, Africa, and south America key causes?
103
In rural or urban areas where do kids have more fevers? What type of pathogen?
Rural especially if even younger
-Usually viruses (hard to diagnose without access to serology in rural settings too)
104
Key investigation in all with fever in Tropics
HIV test
105
3 Rs of vaccines
Routine - ?need updated
Required - Eg yellow fever regulations
Recommended - risk is behaviour related
106
Types of vaccine
Replicating virus vaccines
– Replicate in vaccines; longer-term immunity
Killed viruses/recombinant protein-often multi-dose
– T-cell memory; long-term immunity
Bacteria
– Always short-term protection
Polysaccharide
– Now conjugated to protein to induce T-cell
memory, booster effect, increased protection.
mRNA: naked encapsulate or viral vector
107
Routine vaccines- name 5
Tetanus/diphtheria/pertussis
* Measles
* Polio
* Pneumococcal
* Varicella
* Influenza (separate lecture)
* HPV, Zoster
108
what is the most common vaccine preventible disease in travellers
Influenza
109
How long does flu vaccine last?
6 months
(decreases by about 9% per month)
110
Diptheria vaccine also has? Primary series? when booster?
Tetanus/Diphtheria/Pertussis [Tdap vaccine]
Primary series: 0, 4 wk, 6 months
Booster after 10 years
111
Measles - who is immune? Doses for protection? given with?
Born before 1957 = immune
2 doses - usually 12-15 months & 4-6 yr
Measles Mumps Rubella
112
Varicella zoster, doses for protection? booster?
2 doses
No booster
113
Which vaccine for shingles which is given to people > 50? What is they've had shingles? What if immunocompromised?
Shingrix
Given 2 doses usually around 2 months apart
Wait 1 year then give the vaccine series anyway
CD4 >200, otherwise decision with a consultant (usually give)
114
Which polio is responsible for the ongoing infections
WPV1
115
Which is ideal pneumococcal vaccine
PVC 20
116
Immunocompromised how can you cover for hep A
Give HepA Ig - lasts 2 months
-If won't mount response to vaccine
117
How many doses for HepB
3 doses (0, 1, 6m unless using accelerated series)
[New expensive Heplisav-B is only 2 doses over 1 month]
118
Which HepE geneotype is bad?
GENOTYPE 1 and 2 - 20% mortality in pregnant women
119
Which vaccine still kills 1/250,000 people? Whos at risk?
Yellow fever
People with thymus disorders
120
Who needs yellow fever booster
HIV, travel to west Africa
121
Key meningitis geography risk ? What season?
Belt across Africa from Senegal/Gambia to Somalia
Dry season December-June (due to dry mucus membranes)
122
Which meningitis vaccine only once licenced for kids
Menveo
123
Important side effect of meningitis vaccine
Gillian barre
124
Key people requiring specific MenB vaccine
Asplenia / complement deficiency
125
Who gets cholera vaccine ?
Aid and refugee workers
Oral vaccine
126
Which bacteria does cholera vaccine also work against
ETEC - has b subunit as well
127
Who gets rabies PrEP ? What does it do? How many doses?
High-risk researchers.
long-stay travellers to high risk areas - eg rural adventure
Prevents need to get rabies Ig if exposed
2 doses day 0 and 7
They STILL NEED rabies vaccine
128
Who needs rabies Ig?
Non-primed - eg 2 doses and >3yrs later
[If you've had 3 doses - you are good for life]
Also get 4 doses of the vaccine [5th dose if immunocompromised AND titres degative after 4]
129
Japanese encephalitis reservoir? Breeding site? Number of vaccines?
Pigs
Mosquitos breed in rice paddy's
2 vaccines 28 days apart - last 1 year
Booster after 1 year - Lasts 10 years
130
Tick-borne encephalitis Vaccine number of doses
3 doses over 5-12 months
131
Which vaccines have egg
yellow fever, measles, mumps, flu
132
Which vaccines contain neomycin
measles, mumps, rubella,
varicella
133
Which vaccine contains streptomycin
Oral polio vaccine
134
which vaccines do you not give in pregnancy
Generally just the ones you don't give to immunocompromised
You Musn't Prescribe BCG Incase They RIP Stat
MMR, varicella, Ty21a, live influenza, HPV
Killed influenza wait till 2nd trimester in
many countries
135
Antimalarials contraindicated in pregnancy
Doxycycline, Malarone, Tafenoquine Primaquine
DMTPeople
[Artemisinins actually fine]
136
Acetazolamide in pregnancy
NOT Safe
137
Breast feeding which vaccine big big contraindicated
Yellow fever
138
Which ART class most interactive with antimalarials? Which antimalarial worst
protease inhibitors most problematic ART drug.
mefloquine is the most problematic;
139
3 vaccines recommended for all travellers
Typhoid
HepA
HepB
140
which meningococcal strain is not in the primary series vaccine
B
[Men ACYW]
141
2 complications of flu vaccine
Egg allergy
Gillian-barre
142
Name 3 complications of PID
Infertility
Chronic pelvic pain
Ectopic pregnancy
143
PID rx
Cef + doxy + metronidazole
144
Gonrrhorea / chlamydia rx
Gon - Ceftriaxone
Chlamid - Doxy
145
Mycoplasma genitalium rx
Doxy + azithro/moxifloxacin
146
Gonococcal vs reactive arthritis
Gonococcal
-Tendosynovitis
-Migratory polyarthritis
- Rash which may pustulate
Reactive
-Tendosynovitis rare
- Rash affects palms / soles
147
Difference between immigrant and refugee
Immigrants choose to move,
whereas refugees are forced to flee
148
Name 5 things you could screen for in a refugee
149
Which migrants should get varicella vaccine?
All kids <13
Screen if >13 and vaccinate if no antibodies
150
name 2 conditions VFRs have in particularly high rates when compared with other travellers
malaria, hepatitis A and typhoid
151
Most common deficiency worldwide
Iron
