(PM3A) Parasitic Infection + Anti-Parasitic Drugs Flashcards

1
Q

How does a parasite meet its nutritional needs?

A

Prolonged contact with another living organism

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2
Q

What is an example of a unicellular parasite?

A

Protozoa

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3
Q

What is an example of a multicellular parasite?

A

Helminths

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4
Q

What are the two classes of parasites?

A

(1) Endoparasites

(2) Ectoparasites

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5
Q

What are examples of endoparasites?

A

(1) Protozoa

(2) Helminths

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6
Q

What are examples of ectoparasites?

A

(1) Lice

(2) Leeches

(3) Scabies

(4) Fleas

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7
Q

What are the main anti-protozoal drugs?

A

(1) Anti-amoebics

(2) Anti-malarials

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8
Q

(1) What is the mechanism of action for pyrimethamine?

(2) What is pyrimethamine?

A

(1) Inhibits DHFR

(2) Anti-protozoal drug

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9
Q

(1) What is mechanism of action for sulphadiazine?

(2) What is sulphadiazine?

A

(1) Inhibits DHPS

(2) Anti-protozoal drug

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10
Q

What is the mechanism of action of doxycycline?

A

Inhibits protein synthesis in 30S ribosomes

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11
Q

What are the main anti-helminth drugs?

A

(1) Anti-nematodes

(2) Anti-cestodes

(3) Anti-trematodes

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12
Q

What is mebendazole?

A

Common anti-helminth drug

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13
Q

What is praziquantel?

A

Common anti-helminth drug

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14
Q

What is niclosamine?

A

Common anti-helminth drug

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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

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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

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17
Q

What is the mechanism of action of niclosamine?

A

(1) Uncouples oxidative phosphorylation

(2) Prevents ATP synthesis

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18
Q

What are protozoa?

A
  • Unicellular
  • Eukaryotic organisms
  • Can use insect/ water vectors
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19
Q

Give examples of protozoal infections.

A

(1) Malaria

(2) Intestinal infections - amoebic dystentery/ toxoplasmosis

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20
Q

What is toxoplasmosis?

A

Infection due to a single cellular parasite

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21
Q

What is malaria?

A

Caused by parasitic protozoa

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22
Q

How is a malaria infection diagnosed?

A

(1) Blood film microscopy

(2) Antigen-based rapid diagnostic tests (RDT)

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23
Q

What infection is blood film microscopy often used for?

A

Diagnosing malaria

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24
Q

What infection is antigen-based rapid diagnostic tests (RDT) commonly used for?

A

Diagnosing malaria

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25
Q

What are the stages of malaria transmission?

A

(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

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26
Q

What is a schizont?

A

A protozoan cell which divides to form daughter cells

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27
Q

What are the symptoms of malaria?

A
  • Fever/ chills/ sweats
  • Headaches
  • Nausea + vomiting
  • Aches
  • Malaiase
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28
Q

What can severe malaria cause?

A
  • Cerebral malaria
  • Organ damage
  • Metabolic damage
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29
Q

How can malaria be prevented?

A

(1) Anti-malarial drugs
(2) Covering
(3) Mosquito nets
(4) Permethrin - insecticide
(5) Vaccine

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30
Q

What are the main malaria prophylaxis medications in the UK?

A

(1) Doxycycline
(2) Mefloquine
(3) Proguanil + atovaquone (Malarone)

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31
Q

What is 1st choice treatment for P. falciparum malaria?

A

(1) Clindamycin
(2) Proguanil + atovaquone (Malarone)

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32
Q

What is the 1st line treatment for malaria in pregnancy?

A

Quinine + clindamycin

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33
Q

What does malaria have widespread resistance to?

A

(1) Chloroquinine

(2) Anti-folates

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34
Q

What is the first line treatment for non-P. falciparum malaria?

A

Chloroquinine

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35
Q

What is amoebic dysentery?

A

Amoebiasis

Infection of amoeba

Causes diarrhoea

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36
Q

What is amoebiasis?

A

Amoebic dysentery

Infection of amoeba

Causes diarrhoea

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37
Q

How is amoebiasis transmitted? What else is it called?

A

Faecal-oral

Amoebic dysentery

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38
Q

How is amoebic dysentery transmitted? What else is it called?

A

Faecal-oral

Amoebiasis

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39
Q

What is the treatment for amoebic dystentery (amoebiasis)?

A

Often self-limiting

Metronidazole - for acute invasive amoebiasis

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40
Q

When can a toxoplasmosis infection be life-threatening?

A

If immunocompromised

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41
Q

What is the treatment for toxoplasmosis?

A

Often self-limiting

Pyrimethamine + sulphadiazine

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42
Q

What is cryptosporidiosis?

A

Parasitic infection

Causes diarrhoea

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43
Q

How is cryptosporidiosis transmitted?

A

(1) Swimming pools/ lakes

(2) Contaminated foods + surfaces

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44
Q

What are the symptoms of cryptosporidiosis?

A
  • Watery diarrhoea
  • Dehydration
  • Weight loss
  • Stomach cramps/ pain
  • Fever
  • Nausea + vomiting
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45
Q

When is cryptosporidiosis life-threatening?

A

If immunocompromised

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46
Q

What is the treatment for cryptosporidiosis?

A

Usually self-limiting and not treated

Nitazoxanide if required

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47
Q

What is nitazoxanide?

A

Drug used to treat cryptosporidiosis when not self-limiting or SEVERE

48
Q

What are helminths? How many types are there? What are they?

A

Parasitic worms

3 types

(1) Cestodes
(2) Nematodes
(3) Trematodes

49
Q

What is a cestode?

A

Parasitic worm

Flatworm/ tapeworm

50
Q

What is a nematode?

A

Parasitic worm

Roundworms

51
Q

What is a trematode?

A

Parasitic worm

Flukes

52
Q

What is/ are other name(s) for flatworms?

A

Tapeworms

Cestode

53
Q

What is/ are other name(s) for tapeworms?

A

Flatworms

Cestode

54
Q

What is/ are other name(s) for cestodes?

A

Tapeworms

Flatworms

55
Q

How are helminths transmitted?

A

(1) Poorly cooked meat
(2) Contaminated water
(3) Faeces
(4) Insects - such as mosquito

56
Q

Where are most species of helminth present?

A

Intestinal tract

57
Q

What are subtypes of cestodes?

A

(1) Cestodaria - less common

(2) Eucestoda - more common

58
Q

What is the head of a cestode called?

A

Scolex

59
Q

What is a scolex?

A

The head of a cestode

60
Q

What are proglottids?

A

Body segment of a cestode

61
Q

What are the common symptoms of a cestode infection?

A

(1) Upper abdominal discomfort

(2) Diarhhoea

(3) Loss of appetite

Often asymptomatic - Worm segments can sometimes be seen in stool

62
Q

How is a cestode infection treated?

A

(1) Niclosamide

(2) Praziquantel

63
Q

What is a nematode?

A

Type of helminth

Can be a threadworm/ hookworm/ roundworm/ whipworm

64
Q

What is the cause of a threadworm infection?

A

Usually transmission of eggs

Faecal-oral

Eggs in faeces

65
Q

How is a threadworm infection diagnosed?

A

(1) Seeing worms in perianal region

(2) Scotch tape test
- Sellotape around anus in morning
- Attaches worms & eggs to tape

66
Q

What is the ‘Scotch Tape Test’ used for?

A

Diagnosis of a nematode (helminth) infection

Tape around anus in morning to attach to eggs and worms

67
Q

How is a threadworm treated?

A

Mebendazole

Good hygiene

68
Q

What is a threadworm?

A

Type of nematode

Type of helminth

Parasite

69
Q

What is a hookworm?

A

Type of nematode

Type of helminth

Parasite

70
Q

What are the symptoms of a hookworm infection?

A

(1) Iron-deficient anaemia

(2) Diarrhoea

(3) Nausea & vomiting

(4) Severe local irritation - from larvae in skin

71
Q

What is the treatment for a hookworm infection?

A

(1) Cryotherapy

(2) Mebendazole - 100mg - BD - 3 days

72
Q

How is a whipworm infection caused?

A

(1) Eggs hatch in the small intestine

(2) Eggs develop in the wall of the intestine

73
Q

How length can a whipworm grow to?

A

50mm

2 inches

74
Q

What are the symptoms of a whipworm infection?

A

Light infestations - asymptomatic

Heavy infestations - bloody diarrhoea & iron-deficiency anaemia

75
Q

How is a whipworm infection diagnosed?

A

Stool examination

Infestation is detectable in stool

76
Q

What is the treatment for a whipworm infection?

A

Mebendazole - 100mg - BD - 3 days

77
Q

What is another name for a roundworm?

A

Ascaricides

78
Q

What is another name for ascaricides?

A

Roundworms

79
Q

How many people worldwide are infected by roundworms?

A

1 billion

80
Q

How long is a roundworm?

A

Up to 50cm long

81
Q

What are the symptoms of a roundworm infection?

A

(1) Often asymptomatic
(2) Peritonitis/ Inflammation/ Visceral damage
(3) Enlargement of liver/ spleen
(4) Toxicity
(5) Pneumonia
(6) Nutritional deficiency

82
Q

What are complications of a roundworm infection?

A

(1) Obstructed bowel - by a bolus of worms

(2) Obstruction of bile duct

(3) Obstruction of pancreatic duct

83
Q

What is the treatment for a roundworm infection?

A

(1) Mebendazole - 100mg - BD - 3 days

(2) Mebendazole - 500mg single dose

84
Q

What are the general treatments for nematodes?

A

(1) Good hygiene

(2) Anti-helminthics
- Mebendazole 100mg

85
Q

What can a 500mg single dose of mebendazole be used for?

A

Roundworm infection

86
Q

What can a treatment of 100mg mebendazole BD for 3 days be used for?

A

(1) Hookworm infection
(2) Whipworm infection
(3) Roundworm infection

87
Q

What is the treatment for a threadworm infection?

A

Mebendazole 100mg single dose

88
Q

What is a single dose of 100mg mebendazole used for?

A

Threadworm infection

89
Q

What treatment is recommended for nematodes in pregnancy?

A

None

90
Q

What is a trematode?

A

Type of parasite

Type of helminth

91
Q

What is a fluke?

A

Type of trematode

Type of helminth

Type of parasite

92
Q

What is a blood fluke?

A

Type of trematode

Type of helminth

Type of parasite

93
Q

What are the different types of fluke?

A

(1) Blood flukes

(2) Tissue flukes
- Liver fluke
- Lung fluke

94
Q

What is the treatment for a blood fluke?

A

Praziquantel

95
Q

What is the treatment for a lung fluke?

A

Praziquantel

96
Q

What is the treatment for a tissue fluke?

A

Praziquantel

97
Q

What is the treatment for a lung fluke?

A

Praziquantel

98
Q

What is/ are another name(s) for a blood fluke infection?

A

(1) Schistosomiasis

(2) Bilharziasis

99
Q

What is bilharziasis?

A

A blood fluke infection

100
Q

What is schistosomiasis?

A

A blood fluke infection

101
Q

What is different about schistosomicides to other trematodes?

A

Male and female

Other trematodes are not

102
Q

(1) What is a fluke?

(2) How long is an adult fluke?

A

(1) Type of trematode -> Helminth -> Parasite

(2) 10-20mm long

103
Q

What are the symptoms of schistosomiasis (bilharziasis)?

A

(1) Transient dermatitis - swimmer’s itch

(2) Dermatitis - abdominal pain - bloody stool - periportal fibrosis - hepatosplenomegaly - CNS effects

104
Q

What is peri-portal fibrosis?

A

(1) Chronic disease

(2) Late-stage complication of schistosomiasis

(3) Due to presence of eggs in portal venules

105
Q

What is hepatosplenomegaly?

A

(1) Disorder of spleen and liver

(2) Swelling of organ beyond normal size

106
Q

What is a portal venule?

A

A division of the hepatic portal vein

107
Q

What is the name of the condition where the spleen and liver enlarge?

A

Hepatosplenomegaly

108
Q

What is hepatosplenomegaly a symptom of?

A

Schistosomiasis (bilharziasis)

Trematode infection

109
Q

What is the treatment for schistosomiasis (bilharziasis)?

A

Praziquantel - 20mg/kg - BD/ TDS

110
Q

What is scabies?

A

Contagious skin condition where mites burrow into the skin

111
Q

What is/ are the treatment(s) for head lice? How does it/ they work?

A

Dimeticone lotion/ liquid
- Suffocates lice - physical treatment

Wet combing
- Mechanical removal

112
Q

What is dimeticone lotion used for?

A

Suffocation of head lice on scalp

113
Q

What is the treatment for scabies?

A

Permethrin 5% cream - (Topical)

Ivermectin (Oral)

114
Q

(1) What is permethrin 5% cream used for?

(2) What is its mechanism of action?

A

(1) Topical treatment of scabies

(2) Disrupts sodium channels -> Leads to paralysis

115
Q

(1) What is ivermectin used for?

(2) What is its mechanism of action?

A

(1) Oral treatment of scabies
- When topical permethrin 5% is not effective

(2) Increases inhibitory neurotransmission -> Leads to paralysis