infections of the skin, soft tissue, and muscle caused by parasites/arthropods Flashcards Preview

Micro last plus one anatomy 5 > infections of the skin, soft tissue, and muscle caused by parasites/arthropods > Flashcards

Flashcards in infections of the skin, soft tissue, and muscle caused by parasites/arthropods Deck (41)
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1
Q

Leishmaniasis
pathogenesis
population
reservoirs

A
  • opportunistic pathogen-female SAND FLY bites infected individual and gets the parasite in the macrophages it ingests
  • the parasite (leishamaniasis) reproduces in the gut of sand fly and then then sandfly bites someone else
  • infected new indiviual’s macrophages are infiltrated by leishamaniasis spp and are killed for further spread to other macrophages
  • usually in HIV pt primarily in Mediterranean
  • IMPORTANT re- dogs and rodents
2
Q

what are the three clinical presentations of leishmaniasis

A
  • visceral
  • cutaneous (L. major, tropica, mexicana)
  • mucocutaneous (L. braziliensis)
3
Q

what does cutaneous leishmaniasis cause

A
  • dry crusty lesions at site where parasite was inoculated- looks like a volcano- enlarges and ulcerates
    causing SCARRING AND IS DEBILITATING

-self limiting but immunity can help

4
Q

mucocutaneous leishamaniasis

A
  • caused by L. braziliensis
  • at first, it looks like a typical cutaneous lesion and months or years later, it will come back as ulcerative lesions at the septum or nasal mucosa
  • thought to be a result of parasite metastasis and an AGGRESSIVE IMMUNE RESPONSE
  • USUALLY THIS STRAIN IS IN SOUTH AMERICA AND CENTRAL AMERICA
  • NO RESOLUTION BESIDES CHEMO
5
Q

what type of immunity is best for leishamaniasis

A
  • cell mediated to kill macrophages

- anitbodies are useless because most are intracellular

6
Q

treatment for leishamaniasis

A
  • heavy metals that are toxic and control via eliminating vectors or reservoirs to interrupt transmission
7
Q

what is onchoceriasis

A
  • river blindness
  • caused by Onchocerca volvulus
  • causes nodules of nematodes in the skin and can cause itching and they can get to eyes where they cause blindness -10yrs
8
Q

pathogenesis of onchoceriasis

A
  • nematode in infected individual
  • BLACK FLY THAT LIVES NEAR WATER- bites infected individual and picks up larvae
  • larvae reproduces in black fly
  • black fly bites another individual and infects them
9
Q

where is onchocerciasis found?

A

Africa but sometimes in central and south America

10
Q

what is important to note about the onchoceriasis volvulus species that causes disease?

A
  • only the replicating or young ones cause pathology

- adult ones are knotted together in subcutaneous nodules

11
Q

diagnosis and treatment of ochocerciasis?

A
  • microfilariae in skin snips or eyes

- treat- IVERMECTIN -REPEATED DOSING

12
Q
mansonella spp
what is it?
how transmitted
reservoirs
symptoms
A
  • a filarial nematode
  • transmitted by a bite of infected MIDGE (Marilyn manson is NOT a midg-et)
  • non-human primates may be reservoirs
  • most infections are asymptomatic but can cause itching, edema, JOINT pain, NOT AS SEVERE AS OCNCHOCERIASIS
13
Q

diagnosis of mansonella

A
  • observing microfilaria on stained blood smears of skin snips
14
Q

dracunculus medinensis

A
  • guinea worm = LARGE
  • infected people get blister from females making toxin that causes lesion
  • infected person gets in the water causing the blister to rupture releasing the worm into the water
  • people drink contaminated water and the cycle begins again
15
Q

how is dracunculus medinensis almost irradicated?

A
  • ensured delivery of clean water

- when find, wind worm out on a stick and break it

16
Q

cutaneous larval migrans

A
  • caused by ancylostoma (hookworms) that normally infect cats and dogs- a. braziliense and a. canium
  • in dogs, dogs poop on soil, humans step on soil and larvae penetrate skin
  • larvae don’t know where to go as they fail to enter blood stream so instead burrow in deeper layers to the epidermis- larvae survive and migrate for 7-10 days
  • causes a HUGE inflammatory reaction called “CREEPING ERUPTION”- AND ALSO SERPENTINE TRACKS
17
Q

sarcoptes scabiei

A
  • scabies mite
  • small roundish, eight-legged arthropods
  • mites of birds and animals but can infect humans
  • homeless pop, overcrowding
18
Q

what does scabies present as?

A
  • itching and usually in the WEBBING and sides of fingers later spreading to wrists, elbows, and trunk
  • lesions appear short, SERPENTINE, slightly raised, cutaneous track along which the mites have burrowed
  • can spread to unrelated areas
19
Q

what does a progressed infection of scabies look like?

A
  • hyperinfection involves thousands of mites and is known as a Norwegian or crusted scabies
  • crusted lesions of hands feet and body
  • VERY contagious due to large amount of female mites
20
Q

scabies diagnosis and treatment

A
  • scrape infected skin and seeing under microscope

- treat- topical treatment and may have to treat family, clean all surfaces

21
Q

lice

A
  • pediculosis

- 3 species infect humans- p humanus (body louse), humanus capitis (head louse), phthirus pubis (crab louse)

22
Q

why is the crab louse called the crab louse

A
  • front legs are smaller than the second and third sets of legs which are clawed like crabs
23
Q

symptoms of lice infestations

A
  • itching
  • pruritic, reddened papules
  • can get secondary bacterial infections
24
Q

head lice

A
  • inhabit hair on head
  • combs, brushes, hats etc
  • FREQUENTLY CONCENTRATED ON THE BACK OF THE NECK AND EARS
25
Q

body lice

A
  • aka cooties
  • on clothing of infected individual
  • adult lice move to body of frequently to get a meal and then hop back onto clothing
26
Q

crab lice

A
  • tx thru sexual contact
  • inhabit hairs of the pubic and perianal region
  • can be found on axillary and facial hair
27
Q

what’s important about head and crab lice infection

A
  • they are mostly sedentary residing at the same hair shaft for days while feeding
28
Q

life cycle of head and pubic lice

A
  • females lay eggs called NITS and attach them to the hair shaft
  • eggs hatch in a week and mature over 3 wks
  • adults live less than one month and females lay 50-100 eggs in a lifetime
29
Q

life cycle of body lice

A
  • primarily clothing living- lay eggs there
  • eggs found in seams of infested garments
  • hatch in a week and mature in 3
  • adults last a month and lay 300 eggs in a lifetime
30
Q

Diagnosis of lice

treatment?

A
  • ID lice or eggs in the hair or in the seams of garments
  • use of microscope
  • treatment- shampoos etc with slow-dose insecticides, retreat 1-2 weeks post initial treatment to kill new eggs
  • clothing, beds etc washed
31
Q

myiasis

A
  • human botfly
  • caused by dermatobia hominis
  • lands on top of a mosquito, mosquito bites you, it enters thru the hole, and then you get infestation of larvae/maggots in subcutaneous tissue.
    -maintains air hole to break in skin
    -matures and then drop to the environment to live and fly off
    subcutaneous phase - can cause pain and foul smelling exudate from the opening in the skin
32
Q

treatment for myiasis

A
  • removed surgically
  • can be forced to surface by covering the lesion with petroleum jelly to block their air hole facilitating their removal
33
Q

chagas disease

A
  • trypoanosoma cruzi
  • transmission- bite and defecation of the infected bug on you and you either scratch it and inoculate yourself or it enters an eye somehow
    -first sign: get a chagoma = romana sign-periorbital swelling
    acute phase- fever malaise, myalgia and hepatosplenomegaly
    -indeterminate phase- asymptomatic- few parasites, hi antibody-most individuals stay here
    -chronic disease- infection of heart, GI and myenteric plexus- decades after
34
Q

diagnosis of chagas?

A
  • acutely- find it in peripheral blood
  • chronically- serology
  • travel hx
35
Q

trichinosis

A
  • caused by trichinella spiralis
  • bear, pig or other wild animal infected with larval form of trichinosis in muscles
  • we eat it-undercooked
  • release in stomach, mature in small intestines and mature into adult forms and larvae enter circulation to encyst into striated muscles -WITHIN MUSCLE CELLS AND MAY SURVIVE FOR YEARS
  • causes muscle pain, fever, periorbital edema, eosinophilia, infect diaphragm, occasional CNS or heart damage
36
Q

symptoms of trichinosis

A
  • depends on where they encyst
  • early infection- diarrhea, ab pain, vomit
  • during larval migration and muscle penetration: fever, chills, eosinophilia and muscle pain
  • pathology due to inflammation and mechanical damage
37
Q

diagnosis of trichinosis

A
  • depends on observation of encysted larvae in muscle tissue
  • aided by presence of eosinophilia, elevated muscle enzyme levels (CPK and LDH), dietary hx, and recognition of symptoms
38
Q

Loiasis- loa loa

A
  • central and west Africa
  • bite of MANGO FLIES
  • EYE WORM
  • little pathology besides “CALABAR SWELLING”
  • PASSAGE THRU CONJUNCTIVA
39
Q

diagnosis of loiasis?

A
  • eosinophilia and microfilariae in the blood
40
Q

lung flukes

A
  • paragonimus westermani
  • leaf like
  • infected person poops, releases eggs in water, gets to freshwater crustaceans (crabs and crayfish)
  • people eat crustaceans
  • go into small intestine and exit thru blood to lungs
  • makes it’s way to lungs and get BLOODY SPUTUM AND COUGH
  • eggs are coughed up and swallowed and reproduce in small intestine where they make eggs that are pooped out
41
Q

symptoms of lung flukes

A
  • blood tinged sputum
  • lung abscess
  • blood and dark eggs in sputum to give RUSTY SPUTUM