Parasitic Infections Flashcards

1
Q

Ascariasis Etiology

A
  • Ingestion of eggs in contaminated food

- Ascaris lumbricoides nematode (roundworm)

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2
Q

Ascariasis S/S

A

Transient cough, urticaria, pulmonary infiltrates, nonspecific abd symptoms
-fever, nonproductive cough, chest pain

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3
Q

Ascariasis Lab

A
  • Adult worms may emerge from mouth, nose, or anus
  • ID eggs in feces
  • Eosiniphilia on CBC
  • Abd ultrasound will ID worms
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4
Q

Ascariasis Management

A

-Worms may migrate to common bile duct, pancreatic duct, appendix
-Heavy infestation may cause intestinal obstruction, vovulus, intussusception, death
Tx: albendazole, mebendazole, or pyrantel pamoate

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5
Q

Ascariasis Prev/Prog

A
  • Infections are high in areas of poor hygiene

- Reinfection is common in endemic areas

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6
Q

Enterobiasis Etiology

A

Enterobius vermicularis (pinworm)

  • ingest eggs from infected individual, contaminated food, infected clothing/bedding
  • Deposit eggs on perianal skin
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7
Q

Enterobiasis S/S

A

Nocturnal perianal pruritius

  • asymptomatic
  • insomnia, restlessness, enuresis
  • mild GI symptoms
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8
Q

Enterobiasis Lab

A

ID eggs or adult worms on perianal skin or in stool

-apply clear tape to perianal skin in early morning and examine under microscope

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9
Q

Enterobiasis Management

A

Tx: single dose of albendazole, mebendazole, or pyrantel pamoate

  • repeat in 2 wks due to frequent reinfection
  • Treat all close contacts
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10
Q

Enterobiasis Prev/Prog

A
  • hand washing
  • washing clothes/bedding will kill
  • easily cured but reinfection is common
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11
Q

Trichinosis Etiology

A

Trichinella spiralis and other Trichinella species

  • ingestion of inadequately cooked pork or game
  • larvae are freed from cyst from gastric acid and passes to small intestine
  • larvae invade intestinal epithelial cells and release larvae
  • invade skeletal muscle
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12
Q

Trichinosis S/S

A

Transient intestinal symptoms followed by fever, myalgias, and periorbital edema

  • asymptomatic
  • HA, cough, dyspnea, hoarseness, rash, subconjunctival and retinal hemorrhages
  • symptoms peak 2-3wks and lasts 2 months
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13
Q

Trichinosis Lab

A

Eosinophilia

-elevated serum muscle enzymes

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14
Q

Trichinosis Management

A
  • No specific therapy
  • Mebendazole or albendazole will limit tissue invasion
  • supportive therapy: analgesics, antipyretics, bed rest, steroids in severe illness
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15
Q

Trichinosis Prev/Prog

A

-Cook meat

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16
Q

Tapeworm Etiology

A
Infected by eating raw/undercooked meat/ freshwater fish
4 Sources
-Beef: Taenia saginata, largest
-Pork: Taenia solium
-Fish: Diphyllobothrium latum
-Dwarf: Hymenolepis nana
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17
Q

Tapeworm S/S

A

Generally asymptomatic

-can have abd pain or GI symptoms (N/D)

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18
Q

Tapeworm Lab

A

CBC: eosinophilia

-infection is discovered by finding proglottids or eggs in stool

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19
Q

Tapeworm Management

A

Tx: praziquantel

20
Q

Tapeworm Prev/Prog

A

-responds well to tx

21
Q

Cysticercosis Etiology

A

Taenia solium

  • fecal contamination of food
  • humans are intermediate host
22
Q

Cysticercosis S/S

A

Seizures, HA, focal CNS deficits

  • altered cognition, psychiatric disease
  • vomiting, papiledema, vision loss
  • intracerebral, subarachnoid, and spinal cord lesions and intraventricular cysts
  • lesions may persist for years before symptoms develop
23
Q

Cysticercosis Lab

A

Brain imaging shows cysts

  • positive serologic test
  • CSF shows lymphocytic or eosinophilic pleiocytosis, decreased glucose, elevated protein
  • ELISA
  • CT or MRI show cysts and perenchymal calcifications
24
Q

Cysticercosis Management

A

Tx: benefits must be weighed against inflammatory response risk

  • Albendazole is tx of choice and is coadministered with corticosteroids
  • Surgically remove cysts
25
Cysticercosis Prev/Prog
Endemic in Mexico, Central and S America, Philippines, SE Asia - High fatality rate if untreated - Sanitation, fully cook pork
26
Cutaneous larva Migrans Etiology
Caused by dog and cat hookworms (Ancylostoma braziliese and canium)
27
Cutaneous larva Migrans S/S
Intense pruitic erythematous papules, usually on feet or hands - serpiginous tracks mark the path of parasite - lesions become vesiculated, encrusted or secondarily infected
28
Cutaneous larva Migrans Lab
Dx based on characteristics of lesion | -no lab or bx is done
29
Cutaneous larva Migrans Management
Mild cases don’t require tx - Thiabendazole (topical) TID x 5 days or more - Systemic tx: albendazole or ivermectin
30
Cutaneous larva Migrans Prev/Prog
- infection common in SE US | - Most common in kids
31
Hookworm Etiology
Ancylostoma duodenale or Necator americanus - larvae penetrate skin and migrate to bloodstream to pulmonary capillaries - carried by ciliary action up bronchi to mouth and are swallowed - attach to mucosa of upper small bowel and mature - suck blood at attachment site
32
Hookworm S/S
Transient pruritic rash, dry cough, wheezing, low-grade fever, anorexia, diarrhea, abd discomfort - asymptomatic - epigastric pain - pallor, weakness, dyspnea, heart failure due to iron deficiency anemia
33
Hookworm Lab
Eggs and occult blood in stool - Dx is based on eggs in feces - eosinophilia is common
34
Hookworm Management
Tx: albendazole or mebendazole | -iron replacement to manage anemia
35
Hookworm Prev/Prog
- Very common in tropical and subtropical regions | - mass tx of children with single dose at regular intervals limits worm burden in endemic areas
36
Schistosomiasis Etiology
Caused by trematode blood flukes - 5 Schistosoma species | -Fresh water snails in endemic areas
37
Schistosomiasis S/S
Acute onset of fever, HA, cough, myalgia, urticaria, diarrhea (bloody) -’swimmer’s itch’ Intestinal: abd pain, hepatomegaly, anorexia, weight loss Urinary: hematuria, dysuria Chronic: may be light and asymptomatic
38
Schistosomiasis Lab
Dx: eggs in feces or urine, bx of rectal or bladder mucosa, positive serology - stool may be neg for eggs early on - CBC: eosinophilia
39
Schistosomiasis Management
Tx: praziquantel (1-2 doses, may repeat in 2 wks) - combine with corticosteroid in severe disease - alternative tx: oxamniquine, metrifonate, artemether
40
Schistosomiasis Prev/Prog
Resolves in 2-8 wks - high cure rates w/ tx - avoid fresh water in endemic areas
41
Scabies Etiology
Sarcoptes scabiei | -acquired through bedding or close contact with infested person
42
Scabies S/S
Severe itching, pruritic burrows, vesicles, and pustules (especially on finger webs and wrist creases, elbows, around axillae, and breasts) - nodular lesions on scrotum, penis, or posterior axillary line - pruritic papules on butt
43
Scabies Lab
Mites, ova, and brown dots of feces visible micoscopically | -scrape each lesion until it is flat
44
Scabies Management
Tx: permethrin cream - dermatitis can last months after eradication of mites - Tx dermatitis with corticosteroid cream - bedding and clothing should be cleaned or set aside in plastic bags for 2 wks - High heat is required to kill mites and ova
45
Scabies Prev/Prog
- crusted/hyperkeratotic lesions should be evaluated for immunosuppression - must tx all persons in household