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Tropical medicine - All clinical images copyright Gorgas course - : Instituto de Medicina Tropical Alexander von Humboldt > GI Nematodes > Flashcards

GI Nematodes Flashcards

(94 cards)

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1
Q

Nematodes also called?

A

Roundworms

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2
Q

Key soil-transmitted helminths? Spell them

A

Roundworm - As-caris lum-bri-colides
Whipworm - Trich-uris trich-iura
Hookworms - An-cylo-stoma duodenale and Necator americanus
Strongy-loides

They do NOT multiply in the host (bar strongy

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3
Q

Ascariasis lumbricoides most commonly affects? life cycle? appearance?

A

Children
Due to consumption of contaminated food. Pass through intestinal wall -> lungs [mature over 10-14 days]

Then migrate to the oesophagus and intestine where they mate and produce eggs after approx 10 weeks
200K eggs per day per worm
which become embryonated egg with larva in faeces
[Non fertilised eggs will not infect]

cream coloured worms 15-40cm (females are longer than males)
Produce 200k eggs/day which can survive in soil for years

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4
Q

Main clinical features of ascaris ? What is lofflers syndrome? Key complications that are rare in other soil helminths?

A

Pneumonitis While migrate through lungs - fever, cough, wheeze (occasionally haemoptysis)
-Lofflers is ascarisis pneumonitis + eosinophilia

Adult worms in GI
-Can cause malabsorbtion
-Intestinal obstruction +/- perf - common in kids
-Biliary obstruction - common in adults
-Pancreatic obstruction
Obstruction is due to bolus of worms in heavy infection

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5
Q

Ascaris dx?

A

Stool microscopy for eggs
Pneumonitis is dx on clinical grounds

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6
Q

Ascaris Rx?

A

Mebendazole 100mg BD for 3 days
Or Albendazole 400mg single dose (may need repeated if heavy infection

Can use Nitazoxanide

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7
Q

Ascaris prevention

A

Hygine and sanitation
Education - Ie not using human excrement for fertilizer
Mass chemo

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8
Q

Hookworm appearance and life cycle

A

1cm tubes which attach to intestinal mucosa via suction
-Fully grown after 2-3weeks
-Lay eggs which are passed in stool
-Hatch in soil and L3 form infect humans
-Goes through skin
-Migrates to lungs then get swallowed

Ancylostoma duodenale is larger than necator americanus

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9
Q

Why anaemia and hypoproteinaemia in hookworm

A

Woms consume approx 0.1ml (0.3 for necator) per day
Also get blood and plasma protein loss at site of attachment

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10
Q

Presentation hookworm

A

Iron deficiency anaemia - accounts for 40% in endemic regions
Vauge abdo sx
cutaneous lava migrans at site of entry (serpiginous rash) if not a. Duo or N. ame

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11
Q

Hookworm Dx

A

Eosinophilia
Stool microscopy for eggs

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12
Q

Rx hookworm

A

Albendazole 3 days

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13
Q

Whipworm name? size? features?

A

Trichuris trichiura
2-5cm
Often Asx, iron deficiency anaemia

Severe infection -> dysentery and rectal prolapse
Can also cause appendicitis

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14
Q

Trichuris trichiura dx ? rx?

A

Obvious if rectal prolapse and visible worms
Stool microscopy otherwise for eggs

Mebendazole best

nitrazoxanide also works

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15
Q

toxocariasis 2 main species?
Usually affects?

A

T canis and T cati (from dogs and cats)
Usually affects children - due to consumption of soil contaminated by dog/cat faeces

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16
Q

2 main syndromes of toxocariasis infection? Rx?

A

Visceral larva migrans
-Pneumonitis, fever, abdo pain, hepatosplenomegaly,… with anaemia eosinophilia and hypergamaglobulinaaemia
-Rx with Albendazole for 5 days

Ocular larva migrans
-granuloma in retina -> visual disturbance / blindness
-Rx with steroids and -azoles
-Often mistaken for retinoblastoma

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17
Q

Which helminths can multiply in host?

A

Aww SCHET they’re multiplying

Strongyloides stercolis
capillaria phillipinensis
hymenolepis nana
[enterobius vermicularis
trichuris trichiura]

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18
Q

Most common worm infection

A

Ascaris

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19
Q

Pin worm name? Lifecycle

A

Entero-bius vermicularis

Adult worms live in the distal small intestine
Male and female mate ->
At night female lays eggs on the perianal skin after 4 weeks
Eggs mature after only 6 hrs

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20
Q

Enterobius vermicularis DX

A

Peri-anal skin sticky spatula then microscopy

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21
Q

Pinworm (Enterobius vermicularis ) rx?

A

Mebendazole / albendazole
Then repeat dose after 2 weeks

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22
Q

Complications of Enterobius vermicularis

A

Female adult worm may enter vagina -> may lay eggs in cervix / fallopian tubes -> abscess

Cause granuloma

Appendicitis

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23
Q

Trichuris trichiura life cycle

A

whipworms in caecum and lay eggs which mature in soil over 2-4 weeks
Ingested
Then larvae invade intestinal mucosa crypts

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24
Q

Most common cause of lofflers syndrome

A

Ascaris

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25
Which worm causes obstruction ? why do kids have obstruction more commonly
Ascaris - Looks like a big tangle of worms They have smaller bowels
26
'my child passed a big brown worm'
Ascaris
27
Which worm causing biliary obstruction? Rx?
Ascaris ERCP If kill it with Mebe/albendazole the worm may just die there and obstruction persists
28
Bar through skin how else can you be infected by hookworm
Also can penetrate oesophagal mucosa -[ie Can be oral]
29
Anaemia in hookworm 2 causes
Parasites drink blood Has to detach from area as it gets necrotic and then will bleed a little
30
Main issue with many worm Rx in returning traveller eg schisto
Only kills adult worm - (doesn't affect larvae) -> should wait 8 weeks after exposure for Rx in returning traveller
31
Intestinal nematodes rx generally
Mebendazole or Albendazole
32
Which GI nematode is most sensitive to therapy
Ascaris
33
Which drug for biliary obstruction caused by asaris used sometiems
Piperazine - paralyses ascaris -> helps with removal attempt surgery / ERCP
34
Hookworm best choice of Rx for community mass chemo
Albendazole
35
Trichuris trichiura best single-agent
Mebendazole
36
Community worm reduction measured using
reduction in prevalence CR - cure rate reduction in eggs/gram ERR - egg reduction rate
37
When mass chemo for worms
Yearly if prevalence >20% 6m if >50%
38
Difference between mass chemo and individual patient rx of worms? Agent for ascaris vs hookworm vs trichuris ?
Mass - single dose Individual - 3 days Ascaris: Either MBZ/ABZ * Hookworm: albendazole better * Trichuris: Mebendazole
39
Who contraindicated for MBZ/ABZ/
1st trimester Pregnant [try and wait til 2nd trimester] <1yr 1-2 years can have a reduced dose
40
Main worms going through skin
Hookworm Stronglyotides
41
Strongyloides life cycle? Infectious stage?
Filariaform larvae L3 [not rhabditiform] -Rhabditiform may become filariaform and autoinfect Eggs laid in intestine and quickly hatch into L1 larvae
42
L1 rhabditiform strongy Oesophagal bulb diagnostic stage
43
L3 filariform strongy - infective
44
Why important to differentiate filariform and rhabditiform strongy in lab ?
Filiariaform means autoinfection is taking place
45
Risks for strongy hyperinfection ? which cytokines important?
corticosteroids, cancer, HTLV-1 TH-2 and IL-5 key
46
Strongy with this means?
Larva currens Autoinfection likely
47
Stongy with cough and wheeze syndrome
Löffler syndrome cough shortness of breath wheezing pulmonary interstitial infiltrates eosinophilia
48
Strongy hyperinfection key issues
GI - Obstruction, ulceration, enteritis, protein-loosing enteropathy, GI bleed. Lung involment more porminent CNS: sepsis + meningitis
49
Mechanism of corticosteroid therapy causing strongy
reduced eosinophil numbers (Th2 cell apoptosis, decreased IL-5) [early lymphocyte death (decreased IL-2) poor mast cell responses in small bowel]
50
Better method for strongy diagnosis than stool microscopy
Baermann method -Cheap and quick - Faeces are suspended in water. The larvae move into the water. They sink to the bottom and can be collected for identification. Agar plate culture -culture stools for 5-7 d -presence of larvae bacteria grows along larvae moving tracks -more sensitive (96%) than Baermann
51
Stongy serology issue for diagnosis
does not distinguish between current or previous infection
52
Strongy Rx
Ivermectin for 2 days, then repeat dose after 2 weeks
53
What infection is strongyloidiasis hyperinfection strongly assoc with?
HTLV-1
54
Papa new guinea - children with swollen belly have which particular sub group of strongyloidiasis
strongyloidiasis fulleborni [Fulle Belly in a recently Borni]
55
strongyloidiasis life cycle and appearance
2mm worms live in small intestine (females in mucosa) -Eggs hatch and release non-infective larvae which are released in faeces. - Develop into worms in soil which then produce a second round of larvae [This stage may be repeated many times] -Humans infected through penetration of skin of this second generation -Skin-> lungs where they are swallowed
56
Only soil-transmitted helminth that can multiply while living in soil?
strongyloidiasis
57
How can strongyloidiasis persist for decades?
Auto reinfection. Occationally the larvae turn into infective ones and penetrate mucosa / perianal skin to start cycle again.
58
Acute strongyloidiasis symptoms ?
-May have itchy site where enters skin -occational cough and wheeze -vauge abdo pain and diarrhoea
59
Why are eosinophils often normal in chronic strongyloidiasis
Become immune tolerant Also strongy inhibits IL5
60
(virtually) pathognomic feature of strongyloidiasis? explain it
larva currens - due to autoreinfection - raised line (serpiginous wheal) surrounded by a erythema (flare) -Moves quickly and comes and goes within hours -Very itchy and confined to trunk usually
61
What happens if you have strongyloidiasis and then become immunocompromised? Eg post transplant. Sx?
Get hyperinfection syndrome - due to rapid increase in worms which invade many other tissues -Bloody diarrhoea - abdo inflammation and micro perfs -peritonitis -Pulm eg haemoptysis -Meningioencepahlitis
62
strongyloidiasis control
footwear Screen those who may require immunosuppressive therapy
63
Enterobius vermicularis eggs
64
L-1 (rhabditoid) Strongy
64
L-1 (rhabditoid) Strongy
65
L-3 (filariform)) Strongy
66
Itchy bum at night what is a complication? Key Ix? Rx?
Vulvovaginitis. Paddle or tape test (AM) Treat all household members (-bendazoles)
67
rx?
Trichuris trichiura -Note key DDx of egg Mebendazole > Albendazole
68
Ascaris lumbricoides (unfertilised)
69
Ancylostoma duodenale / Necator americanus
70
Who am I
Ascaris
71
Ancyclostoma duodenale (sharp teeth)
72
Necator americanis (cutting plate)
73
Surface of nematodes called
Cuticle
74
Whats the red arrow pointing to?
Spicule (strongy)
75
Whats this showing?
Spicule - Trichuris Trichiura
76
Develops cough and wheeze. Blood film shows this - whats most likely?
Loeffler Syndrome - Eosinophilia Ascaris > hookworms > Strongyloides
77
Develops cough and wheeze. Blood film shows this - whats most likely?
Loeffler Syndrome - Eosinophilia Ascaris > hookworms > Strongyloides NASA mneumonic Necator, Ancylostoma, S rongyloides, Ascaris
78
Trichuris trichiura: barrel shaped , thick, shell, mucus plug at both poles. Bile stained
79
Trichuris trichiura
80
Ascaris lumbricoides Unfertilized egg
81
Ascaris lumbricoides Fertilized egg Mamillated
82
Ascaris lumbricoides Fertilized egg Decorticated
83
Enterobius vermicularis
84
Ancylostoma duodenale / Necator americanus Egg - : transparent thin shell , multicellular embryo (4 8/16 cells), blunt rounded ends. There is a clear space between the segmented ovum and the shell.
85
Hookworm egg
86
Ancylostoma duodenale
87
Necator americanus
88
Feal oral egg transmission helminths
EATT Enterobius vermicularis Ascaris lumbricoides Trichuris trichiura Toxocara canis/catis
89
Name 2 medications causing eosinophilia
antibiotics (e.g. beta l actams , quinolones , sulfas) NSAIDS, anti epileptic drugs H2 blockers
90
Name 3 infections other than helminths causing eosinophilia
Bronchopulmonary aspergillosis Coccidioidomycosis Scabies, Myiasis Cystoisospora Congenital toxoplasmosis HIV (allergies, eosinophilic folliculitis
91
Name 2 non infectious causes of eosinophilia
Contact dermatitis / psoriasis IBD Asthma Hypereosinophilic syndrome Malignancy Drug reaction
92
65F immigrant from Cambodia 20 y prior Notes mild abdominal pain Raised eosinophils. Stool O&P negative
Strongyloides stercoralis
93
Larva currens (Strongyloidies stercoralis)

Tropical medicine - All clinical images copyright Gorgas course - : Instituto de Medicina Tropical Alexander von Humboldt (26 decks)

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