Pathophys-Day 3 Bugs, Bites, Stings Flashcards
Chagas disease acute presentation
Local erythema and LAD
Romana sign - painless edema of palpebrae
Fever, malaise, anorexia, edema extremity
Chagas disease chronic presentation
Years to decades later
Cardiac and GI manifestations:
Failure arrythmia, megacolon etc
Treatment for Chaas
Nifurtimox and benzimidazole
American trypanosomiasis (Chagas disease) is caused by?
Reduvid bug carrying T cruzi
African sleeping sickness caused by?
Tsetse flies carrying T brucei
African tryp infection compared to american?
Direct fly bite injects trypanosome into skin which migrates to blood stream
African trypanosomiasis presentation
Chancre
LAD
Neurologic manifestations - irritable, personality, daytime somnolence, insomnia
African tryp treatment
Suramin DOC for early
Pentamidine
Eflornithine - both hemolymph and CNS dz
Where is onchocerciasis endemic?
Sub-saharan Africa (part) and parts of South America
Onchocerciasis presentation?
Subq nodules located on top of bony prominences
Intermittent severe itching
Thickening of the skin
Conjunctivitis, glaucoma, and blindness
Onchocerciasis treatment
ivermectin
nodulectomy
What is the Mazzotti reaction?
Potentially severe reaction to DEC treatment for onchocerciasis. So common that it is diagnostic for onchocerciasis (skin patch test).
Help diff from syphillis?
What is tungiasis?
Burrowing flea infestation of skin that causes nodules and erythema
Tungiasis treatment
Early: remove flea with needle Late: curettage, excision Topical creams Niridazole Tetanus prophylaxis Prevention: shoes, don't sit on beach
Cutaneous myiasis what is it?
Botfly deposits Dermatobia hominis larvae in skin which inhabits wound causing dermis to boil
What is the best treatment for cutaneous myiasis?
BACON
Do not remove forcibly!
Botfly localized to
Belize etc
Cimicids are also known as
bed bugs
What is the characteristic bedbug bite pattern?
Breakfast, lunch, dinner linear 3
Bedbugs can spread/worsen these diseases
Hep B and Chagas (vector)
Asthma (feces)
Pediculosis capitis aka
head lice
pediculosis corporis
body lice
phthiriasis pubic
pubic lice
Lice facts
Live 2 days off of host
Live 1 month
Direct contact spread
Treat 1% permethrin 10 min
Body lice are vectors for:
Typhus (rickettsia prowazekii) Trench fever (Bartonella) Relapsing fever (Borrelia)
Maculae cerulae may be caused by:
body and pubic lice
Do scabies act as vectors?
No
Scabies is caused by
Sarcoptes Scabiei
Where are scabies most commonly found on the body in adults?
Interwebs
Wrist flexor surfaces
Elbows
Penis, scrotum, umbilicus
Where are scabies most commonly found on the body in infants?
Head and face
Scabies dx
Skin scrape showing either mites, feces, or eggs
Scabies treatment
Permethrin 5% to all skin 2x wk apart or sulfur 5-10% in petrolatum 3 nights
How long is the dormant period of a scabies infection?
1 month plus because you have to mount an immune response to it
Brown recluse pathogenesis
Sphingomyelinase D is the major toxin
Interacts with serum amyloid
Also hyaluronidase allows eschar to follow gravity
Brown recluse bite tx
None really, maybe prednisone
Ice
Hobo spider biet S/S
Headache, nausea, fatigue
Possibly necrosis and amputation
Hemolysis and thrombocytopenia possible
Black widow bite pres
Initial: erythema, sweating
Worst: abdominal pain Muscle spasms/paralysis HA Nausea Hypertension
Black widow bite treatment
IV Ca gluconate
Analgesics
Antivenin if severe
Black widow pathogenesis
depletion of acetylcholine at motor nerve endings and release of catecholamines at adrenergic endings
