Parasites for the Primary Care Physician Stephen J. Gluckman, M.D., F.A.C.P.
Case 1 A 22 year old woman see you for several weeks of crampy abdominal pain and loose stools – Travel: Philadelphia – Diet: Unremarkable – Medications: Triphasil for 3 years – Physical Examination: Normal – Stool Culture: negative x 1 – Stool for O and P: loaded with Iodamoeba butschlii trophozoites and cysts WHAT IS YOUR NEXT STEP?
Case 2 A 45 year old man has a history of 4 days of watery diarrhea, abdominal cramps, bloating, and flatulence. His 46 year old wife was recently diagnosed with irritable bowel syndrome. One of their two children has been seeing a pediatrician because of failure to gain weight. The other child is well.
Case 2 (cont) Travel: nothing remarkable other than frequent trips to a vacation home in the mountains – Having been well trained you naturally think of giardia. However you are told that the drinking water comes from a public reservoir and is well chlorinated. NOW WHAT?
Giardiasis Epidemiology – Cysts live in cold water for months – Cysts are relatively resistant to chlorine – Associated with decreased IgG and secretory IgA Clinical – Asymptomatic – Acute diarrhea – Chronic malabsorption Treatment – Metronidazole: 250 TID x 5-7 days – paromomycin
Case 3 A student from the emergency room calls you on August 6th about a patient he has just evaluated for severe headache, fever, rigors, and diffuse myalgias. Examination is normal. WBC 4500 with normal differential. The student’s tentative diagnosis is “flu” and has called to ask your advice about treatment with amantidine v. oseltamivir. YOUR RESPONSE?
“Flu” in the Summer Rocky Mountain Spotted Fever Ehrlichiosis Anaplasmosis Malaria Babesiosis
Babesiosis (cont) Laboratory – Anemia, leucopenia, thrombocytopenia Diagnosis – Peripheral smear: looks like P. falciparum, tetrads – Serum antibody test Treatment – Quinine/Clindamycin – Atovaquone/Azithromycin
Case 4 You are referred a 26 year old woman who has had three episodes of trichomonas in the last 6 weeks. She is married and monogamous. They both have been treated on each occasion. All treatment was with metronidazole. The first course was with 2 grams as a single dose. The second was 250 mg TID for 7 days. The last was 250 mg TID for 21 days. On each occasion she responded, but then the symptoms recurred IS SOMEBODY CHEATING? NOT NECESSARILY
Relapsing Trichomoniasis Is the diagnosis correct? – Can not distinguish the etiology of vaginitis without laboratory testing. Have ALL of the partners been treated? – Need to explore this in a non-judgmental way Was the medication taken properly? – Adherence is always an issue with metronidazole Resistance occurs – Can culture and get MIC’s
Trichomonas (cont) Treating resistant strains – High dose metronidazole – Combine with intravaginal metronidazole – Tinidazole – Nonoxynol 9
Case 5 A 12 year old Nicaraguan girl, who recently immigrated to the U.S. was seen in a regional health center because of malaise and loose stools A stool smear revealed
NOW WHAT?MAKE SURE YOU ARE USING AN EXPERIENCED LABORATORY
Case 6 A 45 year old lawyer is generally healthy. He plays racquetball four times a week and sweats heavily. He has noticed some peri-anal discomfort, primarily itching, for the last several weeks. He called his physician who suggested that his discomfort was due to a combination of irritation from sweating and general anxiety related to an upcoming major trial. He prescribed Tucks and Ativan which gave the patient partial relief from his symptoms. The patient’s 8 year old daughter, who has previously slept well is now getting up in the middle of the night. Her school work is suffering. A 3 year old child, two older children, and his wife are fine. NOW WHAT?
Epidemiology – Widespread in the USA – Widespread in the house Diagnosis Scotch Tape Samples% Positive 1 50 2 90 3 99 Treatment: single dose of mebendazole – Be cool. Do not make a project out of hygiene – Treat the entire household – Treat the entire household again in two weeks
Case 7 A 28 year old woman who grew up in Puerto Rico but has been in this country for the past 8 years has difficult to control SLE. She has required high dose prednisone therapy for the past 4 months to control her SLE. She is now admitted with fevers and rigors. The only localizing symptom has been watery diarrhea for the past 2 weeks. Blood cultures: 2 sets growing E. coli Chest x-ray: normal Stool Culture: normal flora Urine Culture: no growth RUO and Pelvic ultrasound: negative She responds to treatment, but returns three weeks later with the same symptoms. This time her blood grows klebsiella. WHAT IS GOING ON HERE?
Strongyloidiasis If there is one intestinal nematode to learn about this is it? – Autoinfection Chronic infection Hyperinfection syndrome – Occurs in persons with defects in CMI Recurrent gram negative bacteremia
Strongyloidiasis Diagnosis – Larva in stool, duodenal aspirate, or sputum – May take many stool specimens Treatment – Ivermectin Confirm cure Consider asymptomatic infection before beginning immunosuppressive therapy in patients from endemic areas.
Case 8 A 5 year old child is sent home from school because the school nurse notices head lice. The child’s father calls in a panic with a number of questions. – What diseases do they carry? None – Should they shave the child’s head? No
Case 8 – What medication should they use to treat them? Pyrethrin (Several preparations, OTC) Permethrin (Nix) (OTC) Malathion (Ovide) Lindane (Kwell) Ivermectin (Stromectol) [not FDA approved for this] – What should they do with bedding and clothing? Wash in routine manner – How many courses of treatment? Retreat in 7-10 days – Should they treat the family dog? No
Case 9 24 year old college student with several weeks of intense pruritus on trunk and associated rash. Minimal response OTC hydrocortisone lotion Sex partner developed similar problem a few days ago
Case 9 Treatment is single dose Ivermectin Pruritus may last for many weeks – This does not require retreatment – Manage with topical steroids and antihistamines
Case 10 A 86 year old healthy man returns from his honeymoon in Egypt with new onset diarrhea. He has about 5 loose to watery stools/day. He is otherwise well. This persists for 2 weeks. Stool cultures and three stools for O & P were negative. NOW WHAT?
There are several reasons why parasites, though present, might not be identified in a stool Who was doing the looking? How many stools were collected? How well were the stools collected? Should one sample the duodenum?
Intestinal Spore-Forming Protozoa Cryptosporidia, Isospora, Microsporidia, Cyclospora All, but microsporidia are common causes of disease in normal hosts In normal hosts the disease is typically an acute diarrhea that lasts 3 - 25 days No leucocytes in the stool Modified acid fast stain can be routinely used to visualize all but microsporidia
Intestinal Spore-Forming Protozoa All are transmitted from human to human – cryptosporidia can also be acquired from animals – resistant to halides All cause disease in the enterocyte. – they do not invade below the epithelial surface All have a world-wide distribution All are frequently AIDS related pathogens All can produce asymptomatic infection
Cryptosporidia AIDS, infants, travelers, endemic, epidemic – Milwaukee, >400,000 cases Modified acid-fast positive Easily seen in small bowel biopsy - if looked for. No proven effective treatment – Paromomycin – Nitazoxanide
Isospora AIDS, infants, travelers Modified acid-fast positive Easily seen in small bowel biopsy Treatment with TMP/SXT
Cyclospora Infants, travelers, endemic, AIDS, Guatemalan raspberries Modified acid-fast positive Looks like cryptosporidia but twice the size – 8 - 10 microns v 4 - 6 microns Treatment with TMP/SXT
Microsporidia Many different species, infecting many different animals - fish, insects, etc. At least 6 genera associated with humans disease, but only two are common – Enterocytozoon bieneusi – Encephalitozoon (Septata) intestinalis Can cause disseminated disease Modified trichrome or florescent stain – hard to see Albendazole works for E. intestinalis
Case 11 A 24 year-old from Montana went on a three week Central American excursion by bicycle. Two days before he returned home he developed low-grade fevers. The next day he had rigors and myalgias. After returning home he was taken to a hospital emergency room by his mother. A blood smear revealed:
Malaria Made Simple Think of it Is it falciparum or not? If falciparum was the traveler in an area where there is chloroquine resistance?
Falciparum Features Where was the traveler? How long has the traveler been back? Smear – High likelihood Only rings High % parasitemia Banana shaped gametocyte Cells of all sizes – Suggestive Multiply infected cells Applique Double chromatin dots
ERYTHROCYTIC HYPNOZOITES S GAMETOCYTES EXO-ERYTHROCYTIC
CASE 12 A 45 year old municipal judge comes in with the compliant of parasites coming out of her skin. For the past 4 months she has noticed intense migratory but total body pruritus. When she scratches at her skin she pick off small black “parasites” that seem to emerge spontaneously. In addition she has been checking her stool and has noticed long mucinous worms.
CASE 12 (cont) She is otherwise well. This all started after a one week vacation in Jamaica She has been to two dermatologist and an infectious diseases physician who have told her she does not have parasites and that “it is in my head”. She has brought in 25 examples wrapped in tissue paper for you to see. Weight stable. Menses normal Physical Examination: well, anxious appearing. Scattered areas of excoriation Basic blood testing normal. Her “parasites” are a collection scabs, lint, dried mucous, and some plant material
CASE 12 Does she have “real” disease? – DELUSIONAL PARASITOSIS (MORGELLONS DISEASE) Can she be effectively treated? Yes Pimozide