presentation parasites

FATIMA MAHDI6 T H YEAR PHARMACYPHARM-D OFFICINE

Intestinal Parasitic Infections

Outline

IntroductionHelminthes Worms

Enterobious Vermicularis Ascaris Lumbricoids Hookworms

Intestinal protozoa Giardia Intestinalis Entamoeba Histolytica

Diarrhea

References

Intestinal Parasites

Intestinal parasitic infections are among the most prevalent infections in humans in developing countries.

May lead to significant morbidity and mortality if not recognized and treated appropriately.

Intestinal Parasites

Caused by intestinal Helminths and Protozoan parasites Helminthes worms: multicellular organisms that

inhabit the human gut Nematodes (roundworms) cestodes (tapeworms) trematodes (flatworms)

Protozoan: unicellular, can multiply inside the human body Giardia intestinalis Entamoeba histolytica Cyclospora cayetanenensis Cryptosporidium spp.

HELMINTHES WORMS

Nematodes

Roundworms that include: ascariasis, hookworm, enterobiasis, strongylodiasis..

Helminthic parasites do not self-replicate, therefore clinical disease requires the acquisition of a heavy burden of adult worms through repeated exposure to the parasite in its infectious stage.

Humans do not develop significant protective immunity to intestinal nematodes.

NematodesEnterobius Vermicularis

Enterobius Vermicularis

Slender white worms, that are several millimeters long.

They cause pinworm infectionPresent in the cecum, appendix, and

ascending colon.Mostly a pediatric conditionTransmission from person to person

(children to parents..)

A small, white worms that can live in the intestines.



Female pinworm migrates to the anal area, lays eggs released to air, clothes, beddings, or hands swallowed by the mouth causing infection.

Symptoms: Itching and prickling in the anal area Restless sleep or difficulty sleeping In females, vaginal itching.

Most patients are asymptomatic

Diarrhea due to inflammation of the bowel wall can occur during acute infection.


Antihelmintics are effective (albendazole, mebendazole, pyrantel pamoate)

Reinfection immediately after the completion of therapy is common; young pinworms may be resistant to drugs.

Successful eradication requires at least 3 doses of medication, separated by 3 weeks.

Itching, irritation, and excoriation should be treated symptomatically.

Enterobius VermicularisAl

bend

azol

e

• Selectively, irreversibly blocks glucose and other nutrients uptake.

• 400 mg PO single dose; repeat in 2-3 weeks if needed.

• Can be mixed with food

Meb

enda

zole • Decrease ATP production in the worm.

• 100 mg PO x1, repeat in 2 weeks

• Take with food

Pyra

ntel

pam

oate • A

depolarizing neuromuscular blocking agent.

• 11 mg (base)/kg PO q2week x2 doses; not to exceed 1 g/dose

• Treatment of choice for pregnant women


Follow-up is recommended if symptoms persist > 2 weeks or if signs of bacterial super-infection occur.

If perianal itching or prickling pain persists perianal swab

Family members or classmates must be treated.

Pregnancy Treatment should be reserved for patients with

significant symptoms. Pyrantel Pamoate > Mebendazole or Albendazole


Advices for Prevention

Personal and group hygiene

Wash hands before eating

Children must stop finger-sucking.

Washing sheets, clothes, and towels in a washing machine, regular laundry soap can eliminate pinworm eggs.

NematodesAscaris lumbricoids

Ascaris lumbricoids (Roundworm)

Largest of the humans intestinal nematodes.Reach 15-35 cm in length in adulthood.Fertilized eggs cannot infect until they

embryonate outside the human body under proper conditions in the soil.

Infection by ingestion of embryonated eggs, reach the small intestine and hatch.

Larva released penetrates the intestinal wall, and migrate to the lungs

Ascaris lumbricoids (Roundworm)

Ascaris lumbricoids

Symptoms: usually asymptomatic

Respiratory symptoms: Fever Nonproductive cough Dyspnea Wheezing

Gastrointestinal (due to high parasite load) N, V Diffuse or epigastric abdominal pain, abdominal tenderness

Ascaris lumbricoids

Complications

Partial or complete bowel obstruction in large numbers

Migrate into the appendix, hepatobiliary system, or pancreatic ducts and rarely other organs such as kidneys or brain.

Appendectitis, pancreatitis. Malnutrition, iron deficiency anemia, and

impairments of growth and cognition. Urticaria early in disease due to allergic reaction

to Ascaris infection

Ascaris lumbricoids

Treatment

Benzimidazoles are effective (albendazole, mebendazole) are first line treatment.

Benzimidazoles are not recommended in pregnant women

Ivermectin and pyrantel pamoate are alternatives.

Ascaris lumbricoids

Albendazole

ATP production in worm energy depletion immobilization, and death.

Adults and children• 400 mg PO x1

day

Mebendazole

Selectively, irreversibly blocks glucose and other nutrients uptake Adults and children• 100 mg PO q12hr

for 3 days

Pyrantel PamoateNeuromuscular blocking agentAdults• 11 mg (base)/kg PO x1

dose; not to exceed 1 g/dose.

• Children • <2 years: Safety not

established• >2 years : 11 mg/kg PO

x1 dose; not to exceed 1 g/dose.

Ascaris lumbricoids

Ivermectin<15 kg: Safety and efficacy not established

15-24 kg: 3 mg PO; may repeat in 3 mo25-35 kg: 6 mg PO; may repeat in 3 mo36-50 kg: 9 mg PO; may repeat in 3 mo

51-65 kg: 12 mg PO; may repeat in 3 mo66-79 kg: 15 mg PO; may repeat in 3 mo

>80 kg: 200 mcg/kg PO onceTake on empty stomach

Piperazine citrateGI or biliary obstruction secondary to ascariasis; causes flaccid paralysis of the helminth by blocking response to worm muscle to acetylcholine.

Pregnant women

Pyrantel Pamoate should be used

Pyrantel pamoate (11 mg/kg up to a maximum of 1 g) is administered as a single dose.

Adverse effects include gastrointestinal disturbances, headaches, rash, and fever.

Ascaris lumbricoids

Ascaris lumbricoids

Prevention

Implementing sanitation and education systems which recommends

Discriminate defecation, educate aginst using human feces as fertilizers

Hand-washing Cleaning fruits and vegetables Avoiding soil consumption.

NematodesHookworms

Hookworms

Hookworms

Two main types Necator americanus Ancylostoma duodenale

Hookworm infection is acquired through skin exposure to larvae in soil contaminated by human feces.

Larva migrates to lungs (mild reactive cough, sore throat) coughed and swallowed to the small intestine adult with teeth attach to mucosa blood and serum protein ingestion.

Most individuals with hookworm infection are asymptomatic, diagnosis by stool examination.

Symptoms: Erythematous, pruritic rash at site of entry.

Cough, fever, wheezing, reactive bronchoconstriction (pulmonary manifestations).

Blood in stool.

Late signs: iron deficiency anemia, hypoproteinemia, and edema.

Hookworms

Complications: Childhood syndrome (iron deficiency anemia, protein

malnutrition, growth and mental retardation, lethargy) Severe anemia affects cardiovascular performance in

adults. Hypoproteinemia

Weight-loss Anasarca (fluid retention in skin) edema Protein-losing enteropathy, with immunoglobulins among the

proteins lost, increased susceptibility to infections .

In patients with high enough iron intake, enteropathy may occur independent of anemia.

Hookworms

Treatment Antihelmintic treatment Iron supplement Appropriate diet Wheezing and cough are managed with inhaled beta

agonists.

In case of malnutrition, support is needed (folic acid)

Severe anemia and patients with CV risks are hospitalized.

Blood transfusion in severe hemorrhage.

Hookworms

Albendazole A single 400-mg

dose (most effective)

Mebendazole100 mg twice daily for 3 days (more effective than a single 500-mg

dose)

Pyrantel pamoate 11 mg/kg doses,

usually over 3 days

Hookworms

Drug of choice in pregnant women

Hookworms

Prevention

Community-wide single-dose Albendazole at intervals of 18 months.

Improve sanitation and access to clean water.

In endemic areas warn against wearing open footwear or walking barefoot in such areas.

INTESTINAL PROTOZOA

Intestinal Protozoa

Invisible, one-celled microorganisms.

Reproduce rapidly takes over the intestine then goes to other organs and tissues.

Some feed on RBC.

They can destroy tissues.

Intestinal Protozoa Giardia Intestinalis

Giardia Intestinalis

Major causative agent of diarrhea

Children>adults

Can be asymptomatic, acute or chronic diarrhea

High infection rate

Transmission fecal-oral, and by ingestion of contaminated water.

Person-person and person-animal transmission


Symptoms Most common in acute phase:

Diarrhea (90%) N,V, AP and distention, flatulance (70%) Malodorous, greasy stools

Most common in chronic phase: Malaise, weakness Anorexia and weight loss

Extraintestinal manifestations: rare Neurologic symptoms (irritability, sleep disorder) Urticaria


Complications

Persistent gastrointestinal symptoms Chronic illness with weight loss Malabsorption syndrome in adults Failure to thrive in children Growth retardation Disaccharidase deficiency Zinc deficiency in schoolchildren Lactose intolerance


Treatment

ATB therapy Fluid and electrolyte management Several month of lactose-free diet for acquired

lactose intolerance

Metronidazole is first line treatment


Metronidazole

• Adults• 250mg PO TID for 5-7 days• 500 mg PO BID for 5-7 days

• Pediatrics 15 mg/kg/day IV/PO divided q8hr for 5 days

Tinidazole

• Adults: 2 g PO once • Pediatrics:

• < 3 years, safety and efficacy not established• >3 Years, 50 mg/kg PO once; 2 g maximum

Take with food.


Paromomycin •Poorly absorbed aminoglycoside, used in

pregnant women •Mostly GI side effects

•25-30 mg/kg/day divided TID PO x5-10 daysWhen the disease is mild and hydration and nutrition can be maintained, therapy can be delayed at least until after the first trimester .

Metronidazole or Tinidazole are alternative agents but should not be used during the first trimester.

Prevention:

Personal hygiene and hand washing , especially in daycare

Travelers to endemic areas not to eat uncooked food (grown, washed with contaminated water)

Water purification


Intestinal Protozoa Entamoeba histolytica

Entamoeba histolytica

Causes the infection “Amebiasis” Intestinal disease (eg, colitis) Extraintestinal manifestations

Liver abscess (most common) Pleuropulmonary, cardiac, and cerebral dissemination

Severe infection for Children (neonates) Pregnant and postpartum women Those using corticosteroids Those with malignancies Malnourished individuals

Transmitted via ingestion of cysts (feces infected soil, water, food handlers..)

Symptoms: can be asymptomaticIntestinal colitis (Amebic colitis)

Gradual onset, over 1-2weeks (different from bacterial dysentery)

Cramping abdominal pain, watery or bloody diarrhea, and weight loss or anorexia.

Fever (less common) Rectal bleeding w/o diarrhea (children)

Fulminant amebic colitis Rapid onset of severe bloody diarrhea Severe abdominal pain Fever Intestinal perforation is common


Extraintestinal symptoms

Amebic liver abscesses, most common extra-intestinal manifestation

Pleuropulmonary disease Peritonitis Pericarditis Brain abscess Genitourinary disease


Treatment Symptomatic, invasive Amebiasis, and amebic colitis

Metronidazole (can work on liver abscesses and can cross BBB)

Treatment with metronidazole is followed by a luminal agent

Symptomatic non-invasive amebiasis luminal agents (ex: Paromomycin)

Broad-spectrum ATB Bacterial superinfection in cases of fulminant amebic colitis and

suspected perforation. Bacterial co-infection of amebic liver abscess.


Metronidazole

•Invasive amebiasis•Kills trophozoites from

intestine and tissues but doesn’t eradicate from the intestine

•Can treat amebic liver abscess, if not successful surgical intervention needed

•Luminal agent should also follow

•Paromamycin not given at same time with metronidazole

•Adults: 500-750 mg PO q8hr for 5-10 days

•Pediatrics: 35-50 mg/kg PO divided q8hr for 10 day

•Pregnancy: B•Lactation not recommended


Tinidazole Intestinal amebiasis and amebic liver abscess in adults and children >=3 yrs

•Adults: 2g PO for 3 days (intestinal) for 5 days (liver)

•Pediatrics: >3yrs 30 mg/kg/day PO , 2 g maximum, for 3 days (intestinal), for 5 days (liver)

ParomamycinIntraluminal amebiasis. Effective in acute and chronic but not extraintestinal

•Adult: 25-35 mg/kg/day divided TID PO x5-10 days

•Pediatrics: 25-35 mg/kg/day divided q8hr PO x7 days

Iodoquinol Luminal amebicide, poorly absorbed, best tolerated when given with meals

•Adults: 650 mg PO PC TID for 20 days

•Pediatrics: 30-40 mg/kg/day divided PO PC TID PO for 20 days; not to exceed 1.95 g/day

Entamoeba histolytica All 3 are category C

for pregnancyCan be

used in pregnant women

ChloroquineExtraintestinal amebiasis

1 g (600 mg base) PO qDay for 2 days, THEN

500 mg (300 mg base) qDay for 14-21 days


Prevention: Education for more sanitation and hygiene Eradicating fecal contamination of water and food Early ttt of carriers in non endemic areas Boiling water before use Vegetables washed and soaked with vinegar

Diarrhea Etiology: viral>bacterial>protozoan

Viral: Watery diarrhea is the most common symptom; stools rarely contain mucus or blood, low grade fever, vomiting. Shorter in duration than bacterial

Bacterial: Result in fever, and bloody diarrhea, severe abdominal pain. (E.coli 1-2 days of watery diarrhea, then bloody). C. difficile infection ranges from mild abdominal cramps and mucus-filled diarrhea, can develop to hemorrhagic. Severe diarrhea (defined as ≥4 fluid stools per day for more than three days)

Parasitic infections typically cause subacute or chronic diarrhea. Most cause nonbloody diarrhea; an exception is E. histolytica, which causes amebic dysentery. Fatigue and weight loss are common when diarrhea is persistent.

Diarrhea

Ask about:

recent contact with someone with acute diarrhoea and/or vomiting

Exposure to a known source of enteric infection (possibly contaminated water or food)

Recent travel abroad.

Selected Oral Antibiotics for Infectious Gastroenteritis*

Organism Antibiotic Adult Dosage Pediatric DosageVibrio cholerae Ciprofloxacin 1 g once NA

Doxycycline†

300 mg single dose 6 mg/kg single dose

TMP/SMX 1 DS tablet bid for 3 days 4–6 mg‡/kg bid for 5 daysClostridium difficile Metronidazole 250 mg qid or 500 mg tid

for 10 days7.5 mg/kg qid for 10–14

daysVancomycin 125–250 mg qid for 10

days10 mg/kg qid for 10–14

daysFidaxomicin 200 mg bid for 10 days NA

Shigella Ciprofloxacin 500 mg bid for 5 days NA

TMP/SMX 1 DS tablet bid 4–6 mg‡/kg bid for 5 daysGiardia intestinalis

(lamblia)Metronidazole 250 mg tid for 5 days 10 mg/kg tid for 7–10

days (maximum 750 mg/day)

Nitazoxanide 500 mg bid for 3 days 1–3 yr: 100 mg bid for 3 days

4–11 yr: 200 mg bid for 3 days

≥ 12 yr: 500 mg bid for 3 days

Entamoeba histolytica Metronidazole§

750 mg tid for 5–10 days 12–16 mg/kg tid for 10 days (maximum 750

mg/day)Campylobacter jejuni Azithromycin 500 mg once/day for 3

days10 mg/kg once/day for 3

daysCiprofloxacin 500 mg once/day for 5

daysNA

References

www.Medscape.comwww.uptodate.comhttp://

www.merckmanuals.com/professional/gastrointestinal_disorders/gastroenteritis/overview_of_gastroenteritis.html

http://www.ncbi.nlm.nih.gov/books/NBK63841/

http://www.cdc.gov/parasites/ Pharmacotherapy Principles & Practice 2007

http://www.medscape.com/

http://www.uptodate.com/

http://www.merckmanuals.com/professional/gastrointestinal_disorders/gastroenteritis/overview_of_gastroenteritis.html








http://www.cdc.gov/parasites/

http://www.cdc.gov/parasites/

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