(PM3A) Parasitic Infection + Anti-Parasitic Drugs Flashcards
1
Q
How does a parasite meet its nutritional needs?
A
Prolonged contact with another living organism
2
Q
What is an example of a unicellular parasite?
A
Protozoa
3
Q
What is an example of a multicellular parasite?
A
Helminths
4
Q
What are the two classes of parasites?
A
(1) Endoparasites
(2) Ectoparasites
5
Q
What are examples of endoparasites?
A
(1) Protozoa
(2) Helminths
6
Q
What are examples of ectoparasites?
A
(1) Lice
(2) Leeches
(3) Scabies
(4) Fleas
7
Q
What are the main anti-protozoal drugs?
A
(1) Anti-amoebics
(2) Anti-malarials
8
Q
(1) What is the mechanism of action for pyrimethamine?
(2) What is pyrimethamine?
A
(1) Inhibits DHFR
(2) Anti-protozoal drug
9
Q
(1) What is mechanism of action for sulphadiazine?
(2) What is sulphadiazine?
A
(1) Inhibits DHPS
(2) Anti-protozoal drug
10
Q
What is the mechanism of action of doxycycline?
A
Inhibits protein synthesis in 30S ribosomes
11
Q
What are the main anti-helminth drugs?
A
(1) Anti-nematodes
(2) Anti-cestodes
(3) Anti-trematodes
12
Q
What is mebendazole?
A
Common anti-helminth drug
13
Q
What is praziquantel?
A
Common anti-helminth drug
14
Q
What is niclosamine?
A
Common anti-helminth drug
15
Q
What is the mechanism of action of mebendazole?
A
(1) Binds to beta-tubulin in intestinal cells of nematodes
(2) Prevents microtubule synthesis
(3) Leads to block of glucose uptake
16
Q
What is the mechanism of action of praziquantel?
A
(1) Increases membrane permeability to Ca2+
(2) Leading to contraction of muscle and paralysis
17
Q
What is the mechanism of action of niclosamine?
A
(1) Uncouples oxidative phosphorylation
(2) Prevents ATP synthesis
18
Q
What are protozoa?
A
- Unicellular
- Eukaryotic organisms
- Can use insect/ water vectors
19
Q
Give examples of protozoal infections.
A
(1) Malaria
(2) Intestinal infections - amoebic dystentery/ toxoplasmosis
20
Q
What is toxoplasmosis?
A
Infection due to a single cellular parasite
21
Q
What is malaria?
A
Caused by parasitic protozoa
22
Q
How is a malaria infection diagnosed?
A
(1) Blood film microscopy
2) Antigen-based rapid diagnostic tests (RDT
23
Q
What infection is blood film microscopy often used for?
A
Diagnosing malaria
24
Q
What infection is antigen-based rapid diagnostic tests (RDT) commonly used for?
A
Diagnosing malaria
25
What are the stages of malaria transmission?
(1) Mosquito bites + injects sporozoites
(2) Infects liver cells
(3) Development of a schizont.
(4) Schizont ruptures
(5) Releases merozoites -> Infect erythrocytes -> Immature trophyzoites
(6) Some immature trophozoites mature to develop more schizonts
(7) Some generate gametocytes - which are ingested by mosquitos
26
What is a schizont?
A protozoan cell which divides to form daughter cells
27
What are the symptoms of malaria?
- Fever/ chills/ sweats
- Headaches
- Nausea + vomiting
- Aches
- Malaiase
28
What can severe malaria cause?
- Cerebral malaria
- Organ damage
- Metabolic damage
29
How can malaria be prevented?
(1) Anti-malarial drugs
(2) Covering
(3) Mosquito nets
(4) Permethrin - insecticide
(5) Vaccine
30
What are the main malaria prophylaxis medications in the UK?
(1) Doxycycline
(2) Mefloquine
(3) Proguanil + atovaquone (Malarone)
31
What is 1st choice treatment for P. falciparum malaria?
(1) Clindamycin
| 2) Proguanil + atovaquone (Malarone
32
What is the 1st line treatment for malaria in pregnancy?
Quinine + clindamycin
33
What does malaria have widespread resistance to?
(1) Chloroquinine
| (2) Anti-folates
34
What is the first line treatment for non-P. falciparum malaria?
Chloroquinine
35
What is amoebic dysentery?
Amoebiasis
Infection of amoeba
Causes diarrhoea
36
What is amoebiasis?
Amoebic dysentery
Infection of amoeba
Causes diarrhoea
37
How is amoebiasis transmitted? What else is it called?
Faecal-oral
Amoebic dysentery
38
How is amoebic dysentery transmitted? What else is it called?
Faecal-oral
Amoebiasis
39
What is the treatment for amoebic dystentery (amoebiasis)?
Often self-limiting
Metronidazole - for acute invasive amoebiasis
40
When can a toxoplasmosis infection be life-threatening?
If immunocompromised
41
What is the treatment for toxoplasmosis?
Often self-limiting
Pyrimethamine + sulphadiazine
42
What is cryptosporidiosis?
Parasitic infection
Causes diarrhoea
43
How is cryptosporidiosis transmitted?
(1) Swimming pools/ lakes
| (2) Contaminated foods + surfaces
44
What are the symptoms of cryptosporidiosis?
- Watery diarrhoea
- Dehydration
- Weight loss
- Stomach cramps/ pain
- Fever
- Nausea + vomiting
45
When is cryptosporidiosis life-threatening?
If immunocompromised
46
What is the treatment for cryptosporidiosis?
Usually self-limiting and not treated
Nitazoxanide if required
47
What is nitazoxanide?
Drug used to treat cryptosporidiosis when not self-limiting or SEVERE
48
What are helminths? How many types are there? What are they?
Parasitic worms
3 types
(1) Cestodes
(2) Nematodes
(3) Trematodes
49
What is a cestode?
Parasitic worm
Flatworm/ tapeworm
50
What is a nematode?
Parasitic worm
Roundworms
51
What is a trematode?
Parasitic worm
Flukes
52
What is/ are other name(s) for flatworms?
Tapeworms
Cestode
53
What is/ are other name(s) for tapeworms?
Flatworms
Cestode
54
What is/ are other name(s) for cestodes?
Tapeworms
Flatworms
55
How are helminths transmitted?
(1) Poorly cooked meat
(2) Contaminated water
(3) Faeces
(4) Insects - such as mosquito
56
Where are most species of helminth present?
Intestinal tract
57
What are subtypes of cestodes?
(1) Cestodaria - less common
| (2) Eucestoda - more common
58
What is the head of a cestode called?
Scolex
59
What is a scolex?
The head of a cestode
60
What are proglottids?
Body segment of a cestode
61
What are the common symptoms of a cestode infection?
(1) Upper abdominal discomfort
(2) Diarhhoea
(3) Loss of appetite
Often asymptomatic - Worm segments can sometimes be seen in stool
62
How is a cestode infection treated?
(1) Niclosamide
| (2) Praziquantel
63
What is a nematode?
Type of helminth
Can be a threadworm/ hookworm/ roundworm/ whipworm
64
What is the cause of a threadworm infection?
Usually transmission of eggs
Faecal-oral
Eggs in faeces
65
How is a threadworm infection diagnosed?
(1) Seeing worms in perianal region
(2) Scotch tape test
- Sellotape around anus in morning
- Attaches worms & eggs to tape
66
What is the ‘Scotch Tape Test’ used for?
Diagnosis of a nematode (helminth) infection
Tape around anus in morning to attach to eggs and worms
67
How is a threadworm treated?
Mebendazole
Good hygiene
68
What is a threadworm?
Type of nematode
Type of helminth
Parasite
69
What is a hookworm?
Type of nematode
Type of helminth
Parasite
70
What are the symptoms of a hookworm infection?
(1) Iron-deficient anaemia
(2) Diarrhoea
(3) Nausea & vomiting
(4) Severe local irritation - from larvae in skin
71
What is the treatment for a hookworm infection?
(1) Cryotherapy
| (2) Mebendazole - 100mg - BD - 3 days
72
How is a whipworm infection caused?
(1) Eggs hatch in the small intestine
| (2) Eggs develop in the wall of the intestine
73
How length can a whipworm grow to?
50mm
2 inches
74
What are the symptoms of a whipworm infection?
Light infestations - asymptomatic
Heavy infestations - bloody diarrhoea & iron-deficiency anaemia
75
How is a whipworm infection diagnosed?
Stool examination
Infestation is detectable in stool
76
What is the treatment for a whipworm infection?
Mebendazole - 100mg - BD - 3 days
77
What is another name for a roundworm?
Ascaricides
78
What is another name for ascaricides?
Roundworms
79
How many people worldwide are infected by roundworms?
1 billion
80
How long is a roundworm?
Up to 50cm long
81
What are the symptoms of a roundworm infection?
(1) Often asymptomatic
(2) Peritonitis/ Inflammation/ Visceral damage
(3) Enlargement of liver/ spleen
(4) Toxicity
(5) Pneumonia
(6) Nutritional deficiency
82
What are complications of a roundworm infection?
(1) Obstructed bowel - by a bolus of worms
(2) Obstruction of bile duct
(3) Obstruction of pancreatic duct
83
What is the treatment for a roundworm infection?
(1) Mebendazole - 100mg - BD - 3 days
| (2) Mebendazole - 500mg single dose
84
What are the general treatments for nematodes?
(1) Good hygiene
(2) Anti-helminthics
- Mebendazole 100mg
85
What can a 500mg single dose of mebendazole be used for?
Roundworm infection
86
What can a treatment of 100mg mebendazole BD for 3 days be used for?
(1) Hookworm infection
(2) Whipworm infection
(3) Roundworm infection
87
What is the treatment for a threadworm infection?
Mebendazole 100mg single dose
88
What is a single dose of 100mg mebendazole used for?
Threadworm infection
89
What treatment is recommended for nematodes in pregnancy?
None
90
What is a trematode?
Type of parasite
Type of helminth
91
What is a fluke?
Type of trematode
Type of helminth
Type of parasite
92
What is a blood fluke?
Type of trematode
Type of helminth
Type of parasite
93
What are the different types of fluke?
(1) Blood flukes
(2) Tissue flukes
- Liver fluke
- Lung fluke
94
What is the treatment for a blood fluke?
Praziquantel
95
What is the treatment for a lung fluke?
Praziquantel
96
What is the treatment for a tissue fluke?
Praziquantel
97
What is the treatment for a lung fluke?
Praziquantel
98
What is/ are another name(s) for a blood fluke infection?
(1) Schistosomiasis
| (2) Bilharziasis
99
What is bilharziasis?
A blood fluke infection
100
What is schistosomiasis?
A blood fluke infection
101
What is different about schistosomicides to other trematodes?
Male and female
Other trematodes are not
102
(1) What is a fluke?
| (2) How long is an adult fluke?
(1) Type of trematode -> Helminth -> Parasite
| (2) 10-20mm long
103
What are the symptoms of schistosomiasis (bilharziasis)?
(1) Transient dermatitis - swimmer's itch
| (2) Dermatitis - abdominal pain - bloody stool - periportal fibrosis - hepatosplenomegaly - CNS effects
104
What is peri-portal fibrosis?
(1) Chronic disease
(2) Late-stage complication of schistosomiasis
(3) Due to presence of eggs in portal venules
105
What is hepatosplenomegaly?
(1) Disorder of spleen and liver
| (2) Swelling of organ beyond normal size
106
What is a portal venule?
A division of the hepatic portal vein
107
What is the name of the condition where the spleen and liver enlarge?
Hepatosplenomegaly
108
What is hepatosplenomegaly a symptom of?
Schistosomiasis (bilharziasis)
Trematode infection
109
What is the treatment for schistosomiasis (bilharziasis)?
Praziquantel - 20mg/kg - BD/ TDS
110
What is scabies?
Contagious skin condition where mites burrow into the skin
111
What is/ are the treatment(s) for head lice? How does it/ they work?
Dimeticone lotion/ liquid
- Suffocates lice - physical treatment
Wet combing
- Mechanical removal
112
What is dimeticone lotion used for?
Suffocation of head lice on scalp
113
What is the treatment for scabies?
Permethrin 5% cream - (Topical)
Ivermectin (Oral)
114
(1) What is permethrin 5% cream used for?
| (2) What is its mechanism of action?
(1) Topical treatment of scabies
| (2) Disrupts sodium channels -> Leads to paralysis
115
(1) What is ivermectin used for?
| (2) What is its mechanism of action?
(1) Oral treatment of scabies
- When topical permethrin 5% is not effective
(2) Increases inhibitory neurotransmission -> Leads to paralysis
