Larva Migrans + Filariasis Flashcards
Albendazole is used to treat…
Treatment of hydatid disease and cysticercosis. it is also used for the treatment of ascariasis ,tricurasis and strongyloidiasis, pinworm, hookworm.
MOA of albendazole
- Inhibits microtubule synthesis by binding to β –tubulin.
- Inhibits mitochondrial reductase causing reduced glucose transport. Intestinal parasites are immobilized and die slowly.
- Larvicidal in hydatid ,cysticercosis, ascariasis and hook worm infections.
- Ovicidal in ascariasis ,hookworm , trichuriasis
Albendazole is ovicidal in…
…ascariasis ,hookworm, trichuriasis
Albendazole RODA
Oral
Larger class of drugs of Albendazole
Benzimidazole carbamate
Absorption and metabolism of albendazole
- Absorption is increased with a fatty meal
- Metabolized in the liver to the active metabolite, albendazole sulfoxide
Caution for use of albendazole and food
Used on empty stomach when used against intraluminal parasites but with a fatty meal when used against tissue parasites.
Clinical use of albendazole
CLM
Hydatid disease
Neurocysticercosis:
Other infections: intestinal capillariasis, giardiasis & taeniasis.
How is albendazole used in neurocysticerosis?
Used with corticosteroid to decrease the inflammation caused by dying organism and it also reduces the duration of course for 21 days
Side effects of Abx (albendazole)
In short term(1-3 days): Mild epigastric pain,diarrhea, nausea, headache & insomnia.
In long term use: abdominal pain, headache, fever, fatigue, alopecia, increased liver enzymes, pancytopenia.
Abx contraindications
Not given during pregnancy, hypersensitive people to benzimidazole drugs & children under 2 years .
Thiabendazole pharmacological action
Chelating agent and form stable complexes with metals including iron, but does not bind with calcium.
Thialbebdazole PK
Should be given after meals and tablets should be chewed
Toxocariasis is an illness of humans caused by
larvae (immature worms) of either the
dog roundworm (Toxocara canis),
the cat roundworm (Toxocara cati)
or the fox roundworm (Toxocara canis).
Toxocaraiasis is a major cause of
blindness
may provoke rheumatic,
neurologic,
or asthmatic symptoms.
Toxocaraiasis can be asymptomatic. True or false?
True
The two main clinical presentations of toxocariasis are
visceral larva migrans (VLM) and ocular larva migrans (OLM).
VLM symptoms
The larvae invade multiple tissues (liver, heart, lungs, brain, muscle) and cause:
fever, anorexia, weight loss, cough, wheezing, rashes, hepatosplenomegaly, and hypereosinophilia.
Death can occur rarely, by severe cardiac, pulmonary or neurologic involvement.
OLM clinical features
The larvae produce various
ophthalmologic lesions, which in some cases
have been misdiagnosed as retinoblastoma,
resulting in surgical enucleation.
OLM often occurs in older children or young
adults, with only rare eosinophilia or visceral
manifestations.
Laboratory diagnosis of VLM includes
- Enzyme immunoassay (EIA) with larval stage antigens extracted from embryonated eggs or released in vitro by cultured infective larvae.
- Toxocara excretory-secretory (TES) antigens
Drugs used in treating Toxocaraiasis
Albendazole is the drug of choice with mebendazole* as an alternatives
CLM is caused by
the larvae of the non-human hookworms Ancylostoma braziliense and A. caninum.
Hookworms causing CLM
Ancylostoma braziliense (dog, cat) – most common
Ancylostoma caninum (dog)
Urcinaria stenocephala (European dogs)
Bunostoma phlebotomun (cattle)
Strongyloides species causing CLM
S pyoncyonis (racoon racoon)
S myoptami (nutrea nutrea)
Pelodera strongyloides
Other organisms causing CLM
Gnathostoma spinergium (dog, cat)
Loa Loa (Calabar swelling)
Fasciola hepatic ( ectopicectopic migration)
Vectors of Brugia malayi are
Mosquitoes of the genus Mansonia.
Elephantiasis is due to ____, lymphatic filariasis is characterized by _____
the engorgement and thickening of skin; lymphedema, or fluid collection due to improper functioning of the lymph system resulting in swelling.
DOC (drug of choice) in filariasis
DEC - diethyl carbamazine
DEC kills microfilariae only. True or false?
False. It kills adults too.
DEC PK
Rapidly absorbed from gut
Half- life is 2-3 hours
The drug should be given after meals.
It is excreted in urine as unchanged or metabolite.
DEC MOA
Immobilizes microfilariae and alters their surface structure, displacing them from tissues & making them susceptible to destruction by host defense mechanism. It has immunosuppressive effects.
Adverse effects of DEC
Fever, malaise, papular rash, headache, GI disturbance, cough. Chest, muscle, joint pain Leucocytosis, Retinal hemorrhage, Encephalopathy, Lymphangitis and lymphadenopathy.
It is not teratogenic.
DEC contraindications
Hypertension, Renal disease patient with lymphangitis.
Other drugs used in treating filariasis include;
Albendazole which kills adult worms.
Ivermectin which kills the microfilariae.
Examples of zoonotic nematodes
Toxocara canis
CLM is caused by
the larvae of the non-human hookworms Ancylostoma braziliense and A. caninum.
