Stings, Bites, and Bugs

Question 1

causes american trypanosomiasias

Answer 1

T. cruzi (chagas disease)

Question 2

causes african trypanosmiasis

Answer 2

T. brucei

Question 3

where is american trypanosomiasias endemic?

Answer 3

central and south america

Question 4

How is T. cruzi transmitted?

Answer 4

infected reduviid bugs and occasionally infected blood

Question 5

Romnana sign

Answer 5

T. cruzi edema of the palpebral and periocular tissue due to entry through the conjunctiva

Question 6

describe the pathogenesis of american trypanosomiasias

Answer 6

reduviid bug bites you –> poops in the bite and deposits T. cruzi in skin –> T. cruzi infects cells and multiplies –> spreads locally or systemically if it gets into blood stream

Question 7

characteristic finding of Chagas dz

Answer 7

swollen eye

Question 8

Acute phase of chagas disease

Answer 8

local erythma and swelling of regional lymph nodes

Question 9

chronic phase of chagas dz

Answer 9

**can occur years to decades later** Cardiac and GI manifestations (heart failure, arrhythmias, megacolon)

Question 10

How is african trypanosomiassis transmitted?

Answer 10

tsetse fly

Question 11

Describe the clinical presentation of african trypanosomiasis

Answer 11

chancre at bite site LN enlargement day time somnolence or insomnia irritability or personality changes

Question 12

predominatly effects cutaneous and ocular tissue

Answer 12

onchocerciasis ( aka river blindness)

Question 13

How is onchocerciasis transmitted?

Answer 13

Simulum black fly (carry the bug onchocerca volvulus)

Question 14

Clinical presentation of acute onchocerciasis

Answer 14

intense puritic dermatitis with subcutaneous nodules over bony prominences

Question 15

Clinical presentation of chronic onchocerciasis

Answer 15

-thickened, wrinkled skin with hyperpigmentation (lizard or elephant skin) -conjunctivitis –> blindness in severe cases

Question 16

Mazzotti reaction:

Answer 16

assc with onchocerciasis treatemtn, severe chills, lymphadenopathy due to break down of organism and the large immune response that results

Question 17

Impregnated flea burrows into skin and causes a 1 cm nodule and erythema

Answer 17

Tungiasis *flea is called Tunga penetrans

Question 18

fly larvae inhabit skin sound or burrow into dermis and cause boil-like lesions, eventually a fly will emerge from the boil

Answer 18

Cutaneous Myiasis **fly is called Dermatobia hominis (aka Human Botfly

Question 19

describe the lesions assc with cutaneous myiasis

Answer 19

1-3 cm painful, tender lesions in which movement it felt

Question 20

How to avoid cutaneous myiasis

Answer 20

avoid belize! wear bug repellant, dry clothes, and do not sit in sandy areas

Question 21

Bites are often seen in a liner group of 3

Answer 21

bed bugs **breakfast, lunch, and dinner

Question 22

causitive agent of chagas disease

Answer 22

reduviid bug (aka kissing bug) carrying t. cruzi

Question 23

Assc with maculae cerulease

Answer 23

lice (body and pubic) = blue/brown hemosiderin laiden macrophages due to intradermal hemorrages at lice feeding site

Question 24

What disease are body lice a vector for?

Answer 24

typhus (rickettsia prowazekii) trench fever (bartonella quintana) relapsing fever (borrelia recurrentis)

Question 25

Where on the body is scabies most commonly found?

Answer 25

interdigital web wrist flexer surfaces of the elbow

Question 26

pathogenesis of scabies

Answer 26

mite burrows in epidermis and lays eggs –> eggs hatch –> continues over and over ==> causes purities

Question 27

How is scabies diagnosed

Answer 27

mites scybala (feces) eggs

Question 28

Describe the bite mark from a brown recluse

Answer 28

central mottling central blister–>eschar –> ulcerates blanched halo erythema surrounding

Question 29

What are the systemic reactions assc with brown recluse bite?

Answer 29

shock hemolysis renal insufficiency DIC

Question 30

What is the major toxin produced by brown recluse?

Answer 30

sphingomyelinase D hyaluronidase allows eschars to spread (in gravity dept reaction)

Question 31

bites are typically not painful and central necrosis can lead to amputation

Answer 31

hobo spider

Question 32

assc with hemolysis and thrombocytopenia

Answer 32

hobo spider bite

Question 33

most common complaint with black widow spider bite

Answer 33

abdominal pain

Question 34

What biochemical effect does the black widow spider have?

Answer 34

depletion of Ach and increased release if catecholamines **not depletion of Ach esterase… sorry….***

Question 35

Tx for black widow spider bite

Answer 35

IV calcium gluconate

Question 36

chancre at bite site LN enlargement day time somnolence or insomnia irritability or personality changes

Answer 36

african trypanosomiasis

Question 37

-thickened, wrinkled skin with hyperpigmentation (lizard or elephant skin) -conjunctivitis –> blindness in severe cases

Answer 37

chronic onchocerciasis

Question 38

intense puritic dermatitis with subcutaneous nodules over bony prominences

Answer 38

acute onchocerciasis

Question 39

1-3 cm painful, tender lesions in which movement it felt

Answer 39

cutaneous myiasis

Question 40

central mottling central blister–>eschar –> ulcerates blanched halo erythema surrounding

Answer 40

brown recluse bite

Question 41

Answer 41

brown recluse bite

“classic red, white, and blue sign”

Question 42

What is this?

Answer 42

scabies

Question 43

Answer 43

bed bugs

Answer 44

cutaneous myiasis