Term
Symptoms can mimic UC, appendicitis
Incubation period: 1-3 weeks
Symptoms: may occur abruptly or come on gradually
-Cramps
-Diarrhea
-Vomiting
-Fever
-Pain
-Anemia
Pass 15-30 stools per day |
|
Definition
|
|
Term
| Extraintestinal amebiasis |
|
Definition
Amebae enter circulation and metastasize causing "sterile" abscess formation (anchovy paste)
Most often mets to liver, but can be any organ.
Only the trophozoite is involved in this process. |
|
|
Term
| Only amoebic species that can infect humans |
|
Definition
|
|
Term
| Best Dx for a patient suspected of having E. histolytica infection/exposure. |
|
Definition
| Amoebic serology by indirect hemagglutination. |
|
|
Term
| 6 high risk populations for amoebic dysentery |
|
Definition
1.) MSM (unsafe sex)
2.) mental patients
3.) travelers
4.) immigrants (latin america)
5.) migrant workers
6.) lower SES in southern US |
|
|
Term
| What group of people pose the greatest threat for the spread of E. histolytica? |
|
Definition
|
|
Term
| What is the most common intestinal parasite in N. america? |
|
Definition
| Giardia lamblia (G. duodenalis) |
|
|
Term
| How is G. duodenalis removed from water? |
|
Definition
| filtration or boiling for 1 min |
|
|
Term
| How many G. duodenalis cysts do you need for 100% infection rate? |
|
Definition
|
|
Term
| What are 4 risk factors for Giardia infection? |
|
Definition
1. living where there is a breakdown in water supply/sanitation
2. working in a day care
3. MSM
4. Drinking water out of lakes or streams |
|
|
Term
| Where do the trophozoites first form in Giardiasis infection? |
|
Definition
|
|
Term
| Where do G. duodenalis trophozoites attach in the digestive tract? |
|
Definition
| To the mucosa of the small bowel, but they DO NOT invade into the mucosa. |
|
|
Term
| Symptoms: Vitamin A deficiency, severe to mild protracted diarrhea; stools are full of mucus, fats, foul smelling (steatorrhea), can be explosive and water; cramps; severe flatulence; anorexia; dehydration and fatigue; stools do not contain pus or blood |
|
Definition
|
|
Term
| What is the best Dx test to do for a patient suspected of having Giardiasis? |
|
Definition
| Giardia antigen test on stool sample. |
|
|
Term
| What is the major non-viral cause of gastroenteritis? |
|
Definition
| Cryptosporidiosis (caused by Crytosporidium parvum) |
|
|
Term
| This GI infection has numerous mammalian reservoirs (including cows), is cosmopolitan and ubiquitous. |
|
Definition
|
|
Term
| You see small (4um) round oocysts in a patients stool when stained with a modified acid-fast stain. What does this patient have? |
|
Definition
| Cryptosporidium parvum infection |
|
|
Term
| 5 characteristics of the C. parvum oocyst |
|
Definition
1. infectious form of the bug
2. 4um in size
3. immediately infectious
4. highly resistant to environmental stress
5. highly resistant to disinfectants |
|
|
Term
| 4 ways of spreading C. parvum |
|
Definition
4 F's
fingers, feces, food, and flies |
|
|
Term
Patient presents with mild-moderate diarrhea (self-limiting); cramps, epigastric pain; nausea; flatulence; watery diarrhea (free of pus or blood); anorexia and fatigue.
The mean incubation of what he has is 7 days.
The illness is expected to last approx 12 days |
|
Definition
|
|
Term
What types (2) of patients have more severe infections with Cryptosporidium parvum?
How are their symptoms different from the other patients? |
|
Definition
AIDS patients, transplant patients (generally all immunocomp patients)
Have debilitating diarrhea, severe fluid loss, more malabsorption (brush border destroyed) |
|
|
Term
| What is the best Dx test for a patient suspected of having Cryptosporidum infection? |
|
Definition
| Cryptosporidium antigen test on stool sample |
|
|
Term
| Treatment for patients with Cryptosporidium infection? |
|
Definition
|
|
Term
| What is the only helminth to multiply in the body? |
|
Definition
|
|
Term
| This phase of helminth infection may trigger eosinophilia |
|
Definition
|
|
Term
| What is the most common roundworm in the US? |
|
Definition
| Pinworm (Enterobius vermicularis) |
|
|
Term
| What roundworm has no lung stage and cannot invade through the skin? |
|
Definition
| Pinworm (Enterobius vermicularis) |
|
|
Term
| Describe how E. vermicularis (pinworm) can increase in numbers without multiplying inside the body? |
|
Definition
| Autoinfection. The eggs are deposited on the perianum and can then be taken up by the fingers during itching. This can then lead to re-infection via the oral route. |
|
|
Term
| What is an effective Dx test for E. vermicularis (pinworm)? |
|
Definition
|
|
Term
| What is the largest human roundworm? |
|
Definition
|
|
Term
| Describe the life cycle of Ascaris lumbricoides |
|
Definition
| Eggs are ingested; larvae hatch in the small intestine and are carried to the liver via portal circulation; larvae are carried through the heart and into the lungs via circulation; larvae break through the alveolar spaces; larvae migrate up the trachea and into esophagus; the eggs are passed back out of the body via the feces. |
|
|
Term
| How do you Dx a patient suspected of having Ascaris lumbricoides infestation? |
|
Definition
| look for eggs in the feces |
|
|
Term
| What type of disease can you get via ingestion of dog/cat roundworm eggs? |
|
Definition
|
|
Term
| 4 features of visceral larva migrans |
|
Definition
1. from dog/cat roundworm eggs
2. intense immune response to migrating worms
3. worms do not complete their life cycle so you cannot use eggs in stools for Dx
4. Dx by history and serology |
|
|
Term
| What type of life cycle/infection mechanism does a whipworm have? |
|
Definition
simple-GI only
Fecal oral transmission |
|
|
Term
| Describe the morphology of whipworm eggs under light Mx |
|
Definition
resemble manicotti dish (oval with little handles on the end)
whip up some manicotti |
|
|
Term
| What serious GI abnormality can be caused by an untreated whipworm infection? |
|
Definition
|
|
Term
| What are the 2 infectious species of hookworm? |
|
Definition
Necator americanus (new world)
Ancyclostoma duodenale (old world) |
|
|
Term
| What helminthic parasite is least susceptible to the antiparasitic drug albendazole? |
|
Definition
|
|
Term
| Describe the hookworm lifecycle? |
|
Definition
| Larvae enters body by burrowing through the skin (usually skin that is in contact with moist soil); goes through circulation and into lungs where it breaks through the alveoli; goes up RB tree, up trachea and goes into the esophagus; goes into the small intestine where it latches onto the wall and feeds on blood; eggs are expelled in the feces and mature in the soil |
|
|
Term
| Describe the morphology of a hookworm egg |
|
Definition
| Smooth outer margin with one side flatter than the other |
|
|
Term
| What potentially severe disorder can hookworms cause? |
|
Definition
| iron-deficiency anemia (especially in women and small children) |
|
|
Term
| How do hookworms cause anemia? |
|
Definition
| When they latch on the SI mucosa they cause a lot of bleeding, some of which they ingest, but most gets lost in the feces. |
|
|
Term
Your patient comes in with red swirly lines all over their back. He has been complaining of some blood in his stool and also reports that last week he was in honduras on a surf trip. During the surf trip he spent some of his time on the beach sun bathing and feeding the feral dogs.
What is a likely Dx? |
|
Definition
| Cutaneous larva migrans caused by dog hookworm |
|
|
Term
| Describe the Strongyloides life cycle |
|
Definition
Rhabditiform larvae from an infected person's stool mature into adult worms and reproduce; rhabditiform larvae hatch from eggs and mature into infectious filariform larvae; filariform larvae penetrate through skin; go along the same circ to lung to GI tract path as hookworm; worms mature in intestine; eggs are deposited in intestinal mucosa and migrate to lumen; rhabditiform larve are expelled in the stool.
These worms can autoinfect when:
rhabditiform larve in colon mature into filariform larvae and burrow through the GI tract and back into the circulation (usually only occurs in immunocomprimised patients). |
|
|
Term
What test would you order if you suspected your patient of having a Strongyloides stercoralis infestation?
What about if they were suspected of having a strongyloides hyperinfection? |
|
Definition
Serology for Ab against Strongyloides
CXR for hyperinfection |
|
|
Term
| 4 features of visceral larvae migrans |
|
Definition
1. due to infection with the dog or cat roundworm equivalent of ascaris, usually through ingestion of larvae
2. wrong host triggers a vigorous immune response
3. usually seen in 2-3 year old chidren with puppies or kittens
4. Eosinophilia, skin rash, shortness of breath
*should order a CXR |
|
|
Term
| 2 features of cutaneous larvae migrans |
|
Definition
1. due to invasion of skin by larvae of dog or cat hookworm
2. creates itchy, serpintine tracks, on feet, butt, or skin that was in contact with moist soil |
|
|
Term
|
Definition
| A superficial fungal infection of the skin |
|
|
Term
| What 2 clinical features can Schistosome mansoni or S. haematobium present with? |
|
Definition
| hepatomegaly and splenomegaly |
|
|
Term
| Describe the life cycle of Schistosomes? |
|
Definition
| Eggs are expelled in feces or urine; eggs are taken up by a fresh water snail (the intermediate host); develop into sporocysts (in snail) which produce cercariae into the water; cercariae penetrate skin; larvae migrate to lungs, heart, and then liver; larvae mature in the liver; worms mature and pair off; worms migrate to mesenteric vessels of bowel or bladder where the female lays eggs; eggs can be excrete in feces or urine or can be retained in the liver to produce chronic schistosomiasis |
|
|
Term
| Where is Schistosome mansoni usually found? |
|
Definition
| Central africa and parts of S. america |
|
|
Term
| What causes urinary schistosomiasis? |
|
Definition
|
|
Term
| What makes Schistosome worms efficient at reproducing? |
|
Definition
| The males and females are physically paired |
|
|
Term
| Describe how Schistosomiasis is Dx |
|
Definition
| finding schistosome eggs in the stool or urine |
|
|
Term
| What is the morphology of a Schistosome mansoni egg? |
|
Definition
| oval in shape with a lateral spine |
|
|
Term
| What is the morphology of a Schistosome haematobium egg? |
|
Definition
| oval in shape with a terminal spine |
|
|
Term
| What is the only Schistosome-related illness found in N. America? |
|
Definition
| Swimmer's itch (caused by T. ocellata) |
|
|
Term
| What US bodies of water are people at risk for deveoping swimmer's itch? |
|
Definition
| Small ponds bordering great lakes; in NYS eastern shore of L. ontario; L. Michigan |
|
|
Term
| What are 2 animal reservoirs for the Schistosome causing swimmer's itch? |
|
Definition
|
|
Term
| This is an abortive infection that does not require treatment. It usually occurs in people who have been in water that was also inhabited by ducks or geese. |
|
Definition
| Swimmer's itch (caused by domestic species of Schistosome) |
|
|
Term
| What species of plasmodium (malaria) has been commonly misdiagnosed as P. malariae? |
|
Definition
|
|
Term
| Describe the malaria life cycle? |
|
Definition
| http://www.cdc.gov/malaria/about/biology/ |
|
|
Term
| What part of the malaria life cycle causes the cycling of fever? |
|
Definition
| When the schizont complete their intense phase of replication within the erythrocytes and lyse the RBC's you have a fever. |
|
|
Term
| What malaria life cycle stage is ingested by the mosquito in the bloodmeal? |
|
Definition
|
|
Term
| What is stage of the malaria life cycle where the parasite replicates in the hepatocytes? |
|
Definition
| exo-erythrocytic schizont |
|
|
Term
| What 2 species of malaria can potentially have dormant phase where they reside in the hepatocytes and can cause latent infection? |
|
Definition
|
|
Term
| All of the symptoms of malaria are caused by this stage of infection? |
|
Definition
|
|
Term
| What is a caveat in the use of chloroquine or mefloquine for malaria prophylaxis? |
|
Definition
| Both drugs prevent clinical expression of malaria while they are being taken. Furthermore, if one is infected by P. vivax or P. ovale, these organisms will enter their latent stage in the hepatocytes and could cause relapse once the drug is removed. |
|
|
Term
| What areas of the world have chloroquine resistance? |
|
Definition
| Most of Africa, India, some parts of South America, New Guinea, and some parts of S.E. Asia |
|
|
Term
| Chloroquine resistant P. falciparum stains independently emerged in the 1950's in what two regions of the world? |
|
Definition
| South America and S.E. Asia |
|
|
Term
| Where is chloroquine resistant P. vivax now found? |
|
Definition
|
|
Term
| Why is P. vivax uncommon in most parts of Africa? |
|
Definition
| Most parts of Africa have populations that over time have lost the Duffey antigen on their RBC's that allows P. vivax to infect these cells. |
|
|
Term
| What is the mechanism of action for chloroquine? |
|
Definition
| It inhibits the haem polymerase in their food vacuole and subsequently causes a build up of ferriprotoporphyrin IX that is toxic to the organism. |
|
|
Term
| What is the mechanism for chloroquine resistance? |
|
Definition
| Its caused by a mutation in PfCRT which is a transmembrane pump in the organisms food vacuole. This mutation causes an increase in the chloroquine efflux from the food vacuole and, thus, decreased time to remain active. |
|
|
Term
| These 3 antimalarial drugs have associated resistant malaria strains where the mechanism of resistance is essentially the same as chloroquine resistance |
|
Definition
| halofantrine, lumefantrine, artemesinins |
|
|
Term
| What are the side effects of chloroquine? |
|
Definition
| Retinal degeneration with long-term use (periodic eye exams should be given to people taking long regimens; these can usually catch degeneration before permanent damage is done); skin itching in west africa; Heart block, hypotension, and cardiac arrest in overdose |
|
|
Term
| What malaria drug is safe to give during the entire pregnancy? |
|
Definition
|
|
Term
| What eye disorder can people taking long regimens of chloroquine come down with? |
|
Definition
|
|
Term
| What are 2 features of mefloquine? |
|
Definition
1. active against most chloroquine-resistant strains of P. falciparum
2. toxic then chloroquine, but not as bad as it is reported in the lay press |
|
|
Term
| What 2 countries can you find chloroquine-mefloquine-resistant P. falciparum? |
|
Definition
|
|
Term
| What are the side effects of mefloquine? |
|
Definition
-vivid dreams/nightmares
-fine tremor or decreased coordination
- drowsiness or dizziness
-can exacerbate seizures (not for patients with epilepsy)
-can exacerbate depression/psych disorders
-can extend PR interval in heart (use with caution with patients on Beta-blockers) |
|
|
Term
| What drug can you take only during the 2nd half of pregnancy for malaria prophylaxis? |
|
Definition
|
|
Term
| What anti-malarial drug is from the cinchona tree? |
|
Definition
|
|
Term
| What are the side effects of quinine use? |
|
Definition
nausea,
vomiting, tinnitus,
disturbed vision, bizarreideation, nightmares
can also have a mild curare-like effect |
|
|
Term
| When would you give a patient quinidine? |
|
Definition
| When they are unable to take oral medication (potentially b/c of a severe case of cerebral malaria). Quinidine is the only anti-malarial drug that can be given IV. |
|
|
Term
| What is the problem with quinidine treatment? |
|
Definition
| most hospitals don't carry it. Have to call around to check for a supply. |
|
|
Term
1. When would you give a patient primaquine?
2. What patients cannot be given this drug? |
|
Definition
1. treatment of people infected by P. vivax or P. ovale
2. patients with G6-PD deficiency |
|
|
Term
| What is primaquine and clindamycin used together to treat? |
|
Definition
| Pneumocystis jeroveci (pneumonia) in AIDS patient |
|
|
Term
| How would you treat a patient with the liver form of P. vivax or P. ovale? |
|
Definition
| Give them a full course of chloroquine followed by primaquine oral daily. |
|
|
Term
| What is the only drug effective against the hypnozoite form of P. vivax or P. ovale infection? |
|
Definition
|
|
Term
1. What is malarone?
2. What is the mechanism of action?
3. Used for treatment, prophylaxis, or both? |
|
Definition
1. combination of atovaquone and proguanil (works well against chloroquine-resistant strains)
2. Atovaquone --> ECT inhibitor; Proguanil --> dihydrofolate reductase inhibitor
3. Both |
|
|
Term
| What is the problem with malarone prophylaxis for malaria? |
|
Definition
|
|
Term
1. What is fansidar?
2. Why is it not Rx more often in the US? |
|
Definition
1. Pyrimethamine/Sulfadoxine
2. Has many, long-lasting side effects |
|
|
Term
1. What is good about using tetracyclines like doxycycline for malaria prophylaxis?
2. What is the caveat? |
|
Definition
1. They are effective against all strains of P. falciparum (including chloroquine-resistant strains)
2. There is a phototoxicity associated with it and most people going into malaria endemic areas will be spending a lot of time in the sun |
|
|
Term
| What anti-malarial drug comes from the wormwood plant? |
|
Definition
|
|
Term
1. What is CoArtem?
2. What is it effective against?
3. How should it be given? |
|
Definition
1. Artemether and lumefantrine
2. More effective against P. falciparum than P. vivax
3. Given orally with high fat meals to improve absorption |
|
|
Term
1. What are the 3 long-lasting anti-malarial drugs?
2. How should they be dosed? |
|
Definition
1. Chloroquine, mefloquine, and fansidar
2. Should be given in a loading phase before travel to the malaria endemic area; Should be given once a week while there. |
|
|
Term
1. What are the 4 short acting anti-malarial drugs?
2. How should they be dosed? |
|
Definition
1. Primaquine, quinine, malarone, CoArtem/artesunate
2. No loading required; should be given once daily |
|
|
Term
| What would you give a patient presenting with malaria-type symptoms who has just come from an area that does not have cholorquine resistance strains? |
|
Definition
|
|
Term
| What would you give a patient presenting with malaria-type symptoms who has just come from an area with chloroquine-resistant strains? |
|
Definition
1. Quinine sulfate followed by doxycycline
or
2. Malarone |
|
|
Term
| Describe why anti-parasitic drugs, typically, have poor availability? |
|
Definition
| Poor availability is due to low profit margins/sole suppliers of some drugs |
|
|
Term
| What are 3 uses of pentamidine? |
|
Definition
1. prophylaxis/treatment of Pneumocystis carinii
2. Treatment of Trypanosoma infection
3. Treatment of leishmaniasis |
|
|
Term
| What is the hypothesized mechanism of pentamidine? |
|
Definition
| May interfere with DNA stabilizing polyamines |
|
|
Term
| What routes can you administer pentamidine (3)? |
|
Definition
|
|
Term
| What are the adverse effects of pentamidine (4)? |
|
Definition
1. Renal dysfunction - usually reversible
2. Hypotension on over-rapid IV infusion
3. Pancreatitis
4. Damage to pancreatic islet cells |
|
|
Term
| What are 4 regimens of choice for Pneumocystis jiroveci? |
|
Definition
1. trimethoprim/sulfamethoxazole
2. clindamycin/primaquine
3. IV pentamidine
4. oral atovaquone |
|
|
Term
| What is Metronidazole effective against (4)? |
|
Definition
| E. histolytica, Giardia lamblia, Trichomonas vaginalis, and C. difficule |
|
|
Term
What iodoquinol used to treat?
When is the best time to give it? |
|
Definition
Used to treat amoebic disease. It is the only anti-amoebic drug that is effective against intraluminal amoebic cysts.
It is recommended as a follow up therapy for patients treated with a course of metronidazole |
|
|
Term
| If you face a shortage of iodoquinol, what drug can you use as a substitute? |
|
Definition
|
|
Term
| What is Tinidazole used to treat? |
|
Definition
| Amoebic disease (dysentery or amoebic abscesses) |
|
|
Term
| What was Nitazoxanide (Alinia) just approved to treat? |
|
Definition
| First drug approved to treat Cryptosporidium parvum and the first to become available in liquid for the treatment of giardiasis. |
|
|
Term
| What other things can be treated by Nitazoxanide (Alinia)? |
|
Definition
Protozoa (E. histolytica and Balantidum coli)
Helminths (Ascaris lumbricoides, Ancylostoma duodenale, Trichuris trichiura, Taenia saginata and other)
Bacteria (H. pylori)
Virus (rotavirus and Hep C)
Its active against all of the big classes of infectious organisms!! |
|
|
Term
| What group of people is Nitazoxanide not approved to treat Cryptosporidium in? |
|
Definition
| AIDS and immunosuppressed |
|
|
Term
What type of antibiotic is Paromomycin (Humantin)?
What is it used as an alternative for in the treatment of lumenal amoebas? |
|
Definition
1. its an aminoglycoside
2. Iodoquinol
*it does not get absorbed in the GI tract |
|
|
Term
| What drug used to be the main drug of choice for most helminths and paralyzes these intestinal worms, allowing them to be expelled in the feces? |
|
Definition
|
|
Term
| What drug IS NOW the main drug of choice for most helminths and paralyzes these intestinal worms, allowing them to be expelled in the feces? |
|
Definition
Albendazole --> more effective than mebendazole
can be used to treat Echinococcus, tapeworm, microsporidia (a protozoan), and many other helminths.
Also can be used to treat Neurocysticercosis. This is basically when the tissue encysted larvae of the pork tapeworm (T. solium) goes to the brain and begins to live there. |
|
|
Term
| What is the drug of choice for microsporidia? |
|
Definition
|
|
Term
| What is the drug of choice for cysticercosis and echinococcal cysts? |
|
Definition
|
|
Term
| What would you give an inoperable partient with either hydatid cyst disease (Echinococcal cysts) or neurocysticercosis. |
|
Definition
|
|
Term
| What drug does the Kingsway charitable foundation of Bristol, VA sell at a reduced price for use in medical missions? |
|
Definition
|
|
Term
| What is ivermectin used to treat (6)? |
|
Definition
| Arthropods (ticks, mites, and insects), Strongyloides stercoalis, Onchocerca volvulus (river blindness); scabies, head lice, and body lice (that can't be treated with topical cream); Norwegian scabies (are not effected by topical cream) |
|
|
Term
If your patient, who was previously diagnosed with AIDS begins to form a crusty, brownish colored scab near his posterior axilla, what could potentially be a cause for this finding?
How would you determine if this was the case? |
|
Definition
Norwegian or crusted scabies
Do a skin scraping and look for scabies mites under the Mx |
|
|
Term
| How would you treat a patient Dx with Norwegian scabies? |
|
Definition
| Oral ivermectin as well as 5% permethrin cream |
|
|
Term
| What is Praziquantel used to treat (4)? |
|
Definition
1. intestinal flukes
2. blood flukes
3. tapeworms
4. all 5 species of Schistosomes |
|
|
Term
What is the mechanism of action of Praziquantel?
Why can't you take praziquantel prophylactically? |
|
Definition
Opens Ca2+ channels which results in vacuolization of worm integument. This sensitizes the flukes to neutrophil attack.
Cercariae and larval schistosomes can still invade skin and are not effected by praziquantel. |
|
|
Term
| What is the only intestinal roundworm not treatable with albendazole? |
|
Definition
|
|
Term
| What is the best choice for treatment of a person with tapeworms? |
|
Definition
Praziquantel
It also kills the tissue encysted larval form of some species |
|
|
