Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_182_библиотеки_им_акад_М_И_Перельмана.pdf
TUNGIASIS
Skin biopsy shows ulceration, acute and chronic
inflammation, and cross sections of an ectoparasite just
beneath the stratum corneum.
TERMINOLOGY
Synonyms
Tunga penetrans: Jigger, chigre, chigoe flea, sand flea
Tungiasis: Nigua, pico
Definitions
Cutaneous infestation by female sand flea, Tunga
penetrans
Origin of "tunga" is probably from Brazil, from a
local word for the infection, although there is a
word in almost every country where tungiasis exists
for the infection &/or flea
Infestations and Other Invertebrate-Related Maladies: Direct Evidence of Invertebrates in Tissue
ETIOLOGY/PATHOGENESIS
Infectious Agents
Main habitat for T. penetrans is warm, dry soil and
sand of beaches, stables, and stock farms
Sand fleas (length of 1 mm) penetrate epidermis then
burrow deep to epidermal-dermal junction
As parasite becomes engorged by host blood, it can
enlarge up to a diameter of 1 cm
Only female fleas can produce typical skin lesion of
tungiasis
In addition to humans, reservoir hosts include pigs,
dogs, cats, cattle, sheep, horses, mules, rats, mice, and
wild animals
CLINICAL ISSUES
Epidemiology
T. penetrans is distributed in tropical and subtropical
countries
No racial predisposition is apparent
VI
1
Outermost layer in a skin biopsy shows an eosinophilic
cuticle and hypodermal layer. The histologic findings
are most consistent with tungiasis.
Presentation
Itching and irritation usually start to develop as female
fleas become fully developed into engorged state
Inflammation and ulceration may become severe,
and multiple lesions in feet can lead to difficulty in
walking
Lesions appear usually on plantar, interdigital, or
periungual regions of the foot, but lesions in leg,
hand, elbow, and buttocks have also been reported
Treatment
Surgical extraction of flea and application of a topical
antibiotic if secondary infection is suspected
Tetanus prophylaxis
Prognosis
Excellent if proper sterile methods are followed for
extraction of fleas
MACROSCOPIC FEATURES
Fortaleza Classification System
Gross appearance of lesion varies according to
progression of infestation process
Stage 1: Penetration of epidermis by female flea’s
proboscis (moments)
Stage 2: Penetration is complete and female
flea is burrowed into host with only 4 air holes,
reproductive organs, and anus exposed, feeding on
blood and expanding her midsection (24-48 hours)
Stage 3a: Midsection has reached its maximum size
and skin of host is stretched thin over it (3 days after
penetration)
Stage 3b: Surface appearance resembles a caldera as
thickness of exoskeleton increases and eggs or feces
may be released (variable)
Stage 4a: Flea begins to die (or has died) and lesion
becomes smaller, darkened, and folded inward (2-3
weeks)
8
Terminology
Tungiasis is a cutaneous infestation by female sand
flea, Tunga penetrans
Clinical Issues
Itching and irritation usually start to develop as
female fleas become fully developed into engorged
state
Stage 4b: Resulting lesion is being expelled by host’s
body and inflammatory repair mechanisms are at
work (day 25 after penetration)
Stage 5: Flea is fully expelled with only keratinized
sloughing skin layers remaining (variable)
TUNGIASIS
Key Facts
Microscopic Pathology
In most cases, section contains portion of
exoskeleton, hypodermal layer, trachea, digestive
tracts, striated muscles, and developing eggs
Biopsy might not contain a perfectly transected flea
Top Differential Diagnoses
Scabies
Myiasis
DIAGNOSTIC CHECKLIST
Clinically Relevant Pathologic Features
Dermoscopy (direct skin microscopy) may be helpful
in identifying organism
Infestations and Other Invertebrate-Related Maladies: Direct Evidence of Invertebrates in Tissue
MICROSCOPIC PATHOLOGY
Histologic Features
In most cases, sections show portions of exoskeleton,
hypodermal layer, trachea, digestive tracts, striated
muscles, and developing eggs
Epidermis is usually hyperplastic and shows
papillomatosis, parakeratosis, and hyperkeratosis
Biopsy might not contain a perfectly transected flea or
macerated tunga
Inflammatory infiltrate may be variably present in
underlying dermis
DIFFERENTIAL DIAGNOSIS
Scabies
Presence of exoskeleton, hypodermal layer, and
developing egg support diagnosis of tungiasis
Myiasis
Hypodermal layer and developing eggs are not
typically seen in myiasis
IMAGE GALLERY
Pathologic Interpretation Pearls
Presence of large numbers of eggs should be a clue to
tungiasis with appropriate clinical history
SELECTED REFERENCES
1. Louis SJ et al: Tungiasis in Haiti: a case series of 383
patients. Int J Dermatol. 53(8):999-1004, 2014
2. Criado PR et al: Tungiasis under dermoscopy: in vivo and
ex vivo examination of the cutaneous infestation due to
Tunga penetrans. An Bras Dermatol. 88(4):649-51, 2013
3. Feldmeier H et al: Tungiasis (sand flea disease): a parasitic
disease with particular challenges for public health. Eur J
Clin Microbiol Infect Dis. 32(1):19-26, 2013
(Left) Cross section shows viable Tunga penetrans, typical subepidermal location, thick corneal layer , and central epidermal pit . Note the
egg-containing uterus underneath the plantar epidermis
reproductive organs of Tunga penetrans
. (Right) H&E section shows macerated tunga and empty organelles.
. No spines are noted. (Center) High-power cross section of a skin biopsy shows the
VI
1
9
This page intentionally left blank
SECTION 2
Invertebrates in Tissue
VI-2-2
TISSUE DAMAGE FROM ARACHNIDS AND INSECTS
Brown recluse spider bites elicit a strong reaction in 10%
of those bitten. Such bites produce red, white, and blue
lesions with tissue necrosis. (Courtesy A. Brooks, CDC/
PHIL.)
TERMINOLOGY
Definitions
Latin: "insectum" (cut into sections); pertains to
organisms of class Insecta (invertebrates)
Adults
Antennae
3 pairs of legs
Compound eyes
3-part body (head, thorax, and abdomen)
7-10 million species and half of known living
organisms on Earth
Beetles, flies, moths, and wasps
Greek: "arachne" (spider); pertains to organisms in
Infestations and Other Invertebrate-Related Maladies: Indirect Evidence of Invertebrates in Tissue
class Arachnida
8 jointed legs
100,000 species
All spiders, scorpions, solifuges, mites, harvestmen,
and ticks
ETIOLOGY/PATHOGENESIS
Environmental Exposure
Insects and arachnids are found worldwide in all
climates with seasonal variation in activity
Important common organisms
Mosquitoes and other biting flies
Deer flies, house flies, and cockroaches
Bees, wasps, hornets, and ants
Spiders, scorpions
Bedbugs, chiggers, and puss caterpillars
Ticks, mites, and lice
Probability of exposure increases in environments
where control of insects and arachnids is limited
Poverty, rural settings, occupation exposure, poor
VI
environmental hygiene
This skin shows a dermal perivascular infiltrate and
scattered eosinophils . Although possibly any insect
bite, the angiocentric pattern may suggest erythema
chronica migrans.
CLINICAL ISSUES
Presentation
Hallmark of most insect or spider bites is local
irritation of skin or mucosa
Erythema
Edema, swelling
Breaks in skin with bleeding, crusting
Pruritus (sometimes with secondary infection)
Pattern irritation (mirroring contact with organism)
Tissue necrosis/breakdown
Exposure zones and lesion number
Insects and spiders have access to human skin in
specific zones related to clothing, time of exposure,
and number of exposures
Bedbugs may produce row of bites on exposed
skin, but most bites are not linear
Mosquitoes often bite exposed skin (ankles, neck,
arms, face) but may bite through clothing and
produce multiple identical lesions, depending on
length and density of exposure
Ticks often feed beneath clothing but need
exposed areas to access skin
Spiders, irritating insects (puss caterpillars),
venomous organisms (centipedes), and painful
biting horse flies or tsetse flies, in general, produce
a single lesion
Although tissue biopsy is not necessary for diagnosis
or treatment, tissue samples may be taken as part of
debridement (e.g., spider bite necrosis) or in unclear
clinical scenarios (persistent nodules with remote
history of insect exposure)
Biopsy or scraping may reveal scabies mites
Bites or infestations are often accompanied by
infiltration of eosinophils &/or basophils
2
2
TISSUE DAMAGE FROM ARACHNIDS AND INSECTS
Clinical Issues
Hallmark of any insect or spider bite is local irritation
of skin or mucosa
Erythema
Edema, swelling
Breaks in skin with bleeding, crusting
Pattern irritation (mirroring contact with organism)
Tissue necrosis/breakdown
Exposure zones and lesion number
Insects and spiders have access to human skin in
specific zones related to clothing, time of exposure,
and number of exposures
In cases of exposure to organisms that carry disease, a
range of laboratory tests may be warranted specific to
symptomatology
Key Facts
Microscopic Pathology
Hypersensitivity reactions
Tissue necrosis
Chronic reactions
Scarring
Top Differential Diagnoses
Primary methicillin-resistant Staphylococcus aureus
skin infections
Secondary bacterial skin infections
Drug reaction
Factitious disorders
Infestations and Other Invertebrate-Related Maladies: Indirect Evidence of Invertebrates in Tissue
Toxic substances from insects or spiders may
destroy tissue and produce necrosis with minimal
inflammation or collaret of inflammation
(neutrophils)
Laboratory Tests
In cases of exposure to organisms that carry disease, a
range of laboratory tests specific to symptomatology
may be warranted
Mosquito exposure in malaria-endemic areas
Malaria testing, serology for arboviruses
Tsetse fly exposure
Screening for African sleeping sickness
Tick exposure
Screening for Lyme disease, babesiosis,
anaplasmosis, Rocky Mountain spotted fever
Treatment
For embedded organisms such as ticks, careful rapid
removal is key to prevent further reaction and reduce
risk of transmission
For organisms that cause tissue destruction as result
of venom, e.g., spiders, close attention to wound with
possible treatment for secondary bacterial infection
(rare) is necessary
For organisms that transmit infections, empiric
therapy for specific infections may be warranted if
symptoms begin
Presumptive/prophylactic treatment for tick that has
fed for > 2 days
Erythema migrans in tick bites (indicating Lyme
disease)
Fever in mosquito bites (indicating malaria or
arbovirus infection)
Prognosis
Although some spider bites may very rarely lead to
death, vast majority of insects cause self-limited local
irritation that may progress to fibrosis and scarring
Rare reported cases of severe systemic complications
(including death) have occurred related to bee
stings, wasp stings, and other insect bites
Some pathogens transmitted by interaction with
insects may lead to fatality without treatment (e.g.,
African sleeping sickness)
MACROSCOPIC FEATURES
Necrosis
Insect or arachnid lesions that produce tissue necrosis
(e.g., hypersensitivity to wasps stings, spider bites)
may show ulceration, secondary purulence formation,
or cavitation
Embedded Parts
Insect lesions that may contain physical structures
embedded in tissue (e.g., tick mouth parts, bot flies,
tunga fleas) may show swelling with obvious foreign
material
MICROSCOPIC PATHOLOGY
Histologic Features
Hypersensitivity reactions
Penetration of skin by insects or spiders may
introduce foreign substances
Elicit response of eosinophils, edema, extravasated
red blood cells, and hyperplastic changes of
overlying epithelium
Tissue necrosis
Toxic substances from insects or spiders may
destroy tissue and produce necrosis with minimal
inflammation or collaret of inflammation
(neutrophils)
Dense inflammation including numerous
neutrophils, abscess formation, and crust may
indicate secondary infection and should warrant
special stains for bacteria
Chronic reactions
Persistence of antigens or allergens may produce
lymphoid aggregates with plasma cells
Scarring
Chronic lesions that have resolved may leave
increased collagen or dense collagen within dermis
VI
2
3
TISSUE DAMAGE FROM ARACHNIDS AND INSECTS
DIFFERENTIAL DIAGNOSIS
Primary Methicillin-Resistant Staphylococcus
aureus Skin Infections
Produces local erythema, edema, tissue breakdown,
and purulence that may be confused with spider bites
Presence of gram-positive cocci, positive culture can
elucidate cause
Secondary Bacterial Skin Infections
Breaks in skin (often from excoriation) from any
cause (including insect/spider lesions) may become
secondarily infected
Presence of bacteria (most commonly gram-positive
cocci), positive culture can elucidate cause
Drug Reaction
May appear identical with eosinophils and edema
Clinical history of new drug treatment
Contact Dermatitis
Many irritants can lead to contact dermatitis, which
usually has distribution related to contact with irritant
but may mimic bites or insect/spider exposures
Factitious Disorders
Picking or other forms of chronic irritation of skin
may produce mimics of insect or spider bite lesions
Psychological evaluation for delusional parasitosis or
other mental conditions leading to picking should be
considered
More common when patients present with multiple
lesions in different exposure zones
"Junkie Itch"
Opiate addicts and users may suffer from delusions of
insects on skin, which leads to aggressive scratching
Infestations and Other Invertebrate-Related Maladies: Indirect Evidence of Invertebrates in Tissue
and excoriations
DIAGNOSTIC CHECKLIST
5. Dominguez-Amorocho O et al: Differences in systemic and
skin migrating-specific CD4 T cells in papular urticaria by
flea bite. Int Arch Allergy Immunol. 160(2):165-72, 2013
6. Fernando DM et al: Necrotizing fasciitis and death
following an insect bite. Am J Forensic Med Pathol.
34(3):234-6, 2013
7. Piccolo V et al: Superficial lymphangitis after insect bite. J
Pediatr. 163(1):299, 2013
8. Hemmige V et al: Trypanosoma cruzi infection: a review
with emphasis on cutaneous manifestations. Int J
Dermatol. 51(5):501-8, 2012
9. Kumar L et al: Autopsy diagnosis of a death due to
scorpion stinging--a case report. J Forensic Leg Med.
19(8):494-6, 2012
10. Oka K et al: Two cases of eruptive pseudoangiomatosis
induced by mosquito bites. J Dermatol. 39(3):301-5, 2012
11. Lavery MJ et al: Bed bugs revisited. Skinmed. 9(1):6-8, 2011
12. Lin CJ et al: Multiorgan failure following mass wasp stings.
South Med J. 104(5):378-9, 2011
13. Vidhate MR et al: Bilateral cavernous sinus syndrome and
bilateral cerebral infarcts: A rare combination after wasp
sting. J Neurol Sci. 301(1-2):104-6, 2011
14. Goddard J et al: Bed bugs (Cimex lectularius) and clinical
consequences of their bites. JAMA. 301(13):1358-66, 2009
15.
Ruff F et al: Stinging Hymenoptera and mastocytosis. Curr
Opin Allergy Clin Immunol. 9(4):338-42, 2009
16. Scherer K et al: Diagnosis of stinging insect allergy: utility
of cellular in-vitro tests. Curr Opin Allergy Clin Immunol.
9(4):343-50, 2009
17. Severino M et al: Large local reactions from stinging
insects: from epidemiology to management. Curr Opin
Allergy Clin Immunol. 9(4):334-7, 2009
18. Asada H: Hypersensitivity to mosquito bites: a unique
pathogenic mechanism linking Epstein-Barr virus
infection, allergy and oncogenesis. J Dermatol Sci.
45(3):153-60, 2007
19. Reisman RE: Unusual reactions to insect stings. Curr Opin
Allergy Clin Immunol. 5(4):355-8, 2005
20. Engler RJ: Mosquito bite pathogenesis in necrotic skin
reactors. Curr Opin Allergy Clin Immunol. 1(4):349-52,
2001
21. deShazo RD et al: Medical consequences of multiple fire
ant stings occurring indoors. J Allergy Clin Immunol.
93(5):847-50, 1994
VI
2
4
Clinically Relevant Pathologic Features
Clinical history that reveals exposure can provide
plausible list of potential offenders
If organism is brought in with patient, it should be
examined and identified by a specialist
Pathologic Interpretation Pearls
Histological differential diagnosis may include
entities more common than insect or spiders lesions,
depending on clinical history
SELECTED REFERENCES
1. An JY et al: Hemichorea after multiple bee stings. Am J
Emerg Med. 32(2):196, 2014
2. Dandoy C et al: Secondary hemophagocytic
lymphohistiocytosis (HLH) from a presumed brown recluse
spider bite. J Clin Immunol. 34(5):544-7, 2014
3. Goddard J: Cutaneous reactions to bed bug bites. Skinmed.
12(3):141-3, 2014
4. Suresh SS et al: Osteomyelitis calcaneum due to a scorpion
sting. J Foot Ankle Surg. 53(3):340-3, 2014
TISSUE DAMAGE FROM ARACHNIDS AND INSECTS
p
p
p
Clinical Lesions and Specimens
Infestations and Other Invertebrate-Related Maladies: Indirect Evidence of Invertebrates in Tissue
(Left) Clinical features
vary depending on the
arthropod species and their
venom. Most commonly,
lesions appear as excoriated
urpuric papules , but
vesicles, bullae, nodules,
erosions, and ulcers can
also occur. (From DP:
Nonneoplastic Derm.)
(Right) The "red, white,
and blue" sign is seen in a
brown recluse spider bite.
The sign is identified by dry
necrotic eschar or ulceration,
surrounded by pale then
erythematous patches. (From
DP: Nonneoplastic Derm.)
(Left) This lesion was
seen on the abdomen
of a patient who had an
adult tick attached, which
was removed forcefully
(leaving tick mouth parts
behind) and producing the
red erythematous lesion.
(Courtesy S. Granter, MD.)
(Right) 10 mm skin punch
biopsy with an embedded,
artially engorged female
lone star tick is shown. This
method is not recommended
and does not prevent tickborne infections, it but does
entirely remove the mouth
arts. (Courtesy R. Pollack,
PhD.)
(Left) An adult female deer
tick was dismembered in
the process of removal,
a common occurrence.
The engorgement suggests
feeding for ~ 2 days.
(Courtesy R. Pollack, PhD.)
(Right) An adult female
lone star tick that fed for ~
1 week demonstrates the
characteristic spot
scutal plate. (Courtesy R.
Pollack, PhD.)
on the
VI
2
5
(Left) The black widow spider
p
is easily recognized by the
dark black shiny body and
legs, and the characteristic
red mark on the abdomen.
(Courtesy P. Smith, CDC/
PHIL.) (Right) This adult
female deer tick had been
attached and feeding for more
than 3 days. (Courtesy R.
Pollack, PhD.)
(Left) An adult bedbug (Cimex
lectularius) is shown with 3
airs of legs, antennae, and
the typical head, thorax, and
abdomen of a bug. Although
they do not transmit disease,
infestations produce multiple
bites and skin lesions for
individuals exposed to them.
(Right) A whole mount of
a Dermacentor variabilis
(adult wood tick) is shown
unengorged, with 4 pairs of
legs and a scutum .
TISSUE DAMAGE FROM ARACHNIDS AND INSECTS
Organism Identification
Infestations and Other Invertebrate-Related Maladies: Indirect Evidence of Invertebrates in Tissue
(Left) Photo shows an adult
squirrel flea captured from a
dwelling suspected of bedbug
infestation. No bedbugs were
found, but there was a squirrel
nest near the window of the
dwelling. (Courtesy R. Pollack,
PhD.) (Right) A whole mount
of a common flea (Pulex
irritans) demonstrates the flat
body and 3 pairs of legs. In
addition to the bites that leave
skin lesions, transmission of cat
scratch disease and plague is
attributed to fleas.
VI
2
6
TISSUE DAMAGE FROM ARACHNIDS AND INSECTS
A
Clinical Specimens
Infestations and Other Invertebrate-Related Maladies: Indirect Evidence of Invertebrates in Tissue
(Left) An adult Pthirus pubis
(crab or pubic louse) is
shown attached to hairs,
which may be any hair on
the body (axilla, facial hair,
chest hair, or eyelashes,
commonly genital hairs).
(Courtesy R. Pollack, PhD.)
(Right) Whole mount
of an adult female crab
louse (Phthirus pubis)
demonstrates the 3 pairs
of "claws" from which
the creature gets its name.
lthough these lice do not
transmit any diseases, they
are commonly sexually
transmitted and difficult to
remove.
(Left) Body lice (Pediculus
species) show antennae
and 3 pairs of legs . They
transmit epidemic typhus,
trench fever, and louseborne relapsing fever caused
by Rickettsia prowazekii,
Bartonella quintana, and
Borrelia recurrentis. They
migrate to the scalp or
clothing, depending on
species. (Courtesy R. Pollack,
PhD.) (Right) Whole mounts
of preserved body lice
demonstrate the 3 pairs of
legs with clasping ends
and the wide, flat abdomen
.
(Left) This tropical bird
mite shows 4 front legs (the
4 back legs were lost in
capture and preparation).
Mites are ubiquitous, but
many species are associated
with several human diseases,
including scrub typhus
transmitted by trombiculid
mites (Leptotrombidium
species) and caused by
Orientia tsutsugamushi.
(Courtesy R. Pollack, PhD.)
(Right) Two mites are
shown in which the 8 legs
can be seen; 4 in the front
and 2 in the back .
VI
2
7