Criado por Amaal Salhieh
mais de 8 anos atrás
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Questão | Responda |
Cellulitis predominant causes | Group A strep and S. aureus |
Cellulitis Treatment | If nonpurulent, Penicillinase-resistant PCN (naf and ox) If risks of MRSA, vanc, linezolid, ceftaroline Other options include clindamycin, TMP-SMX, doxycycline |
Erysipelas etiology | GAS |
Erysipelas Treatment | Penicillin Macrolide as an alternative |
Furuncles & Carbuncles etiology | S. aureus |
Furuncles & Carbuncles Treatment | Apply heat to facilitate drainage of pus Antistaph antibiotic (naf, oxa), unless MRSA risks |
Impetigo etiology | GAS & S. aureus |
Impetigo Treatment | Penicillinase-resistant PCNs (naf, oxa, amoxicillin-clavulanate) Add coverage if risks for MRSA |
Necrotizing Fasciitis Etiology | Type I: Polymicrobial (usually anaerobe & GAS) Type II: GAS |
Nec. Fasciitis Treatment | Debridement Broad spectrum antibiotics |
Lymphangitis acute | GAS, S. aureus, Pasteurella Use a GPS to track the cute lymph channels |
Lymphangitis Chronic | Fungal (sporothrix schenckil) Mycobacterial (M. marinum) |
What is lymphadenitis? | Acute or chronic inflammation of the lymph node |
What is lymphangitis? | Inflammation of lymphatic channels |
Infectious arthritis etiology | S. aureus most common Strep, gram neg possible N. gonorrhoeae (~3%) |
Osteomyelitis most common etiology | S. aureus |
Osteomyelitis If IVDU, think.. | S. aureus or Pseudomonas |
Osteomyelitis If sickle cell, think.. | Salmonella |
Osteomyelitis If jaw, think.. | Actinomyces |
Osteomyelitis Mechanism of Infection | _Hematogenous seeding _Contiguous spread from adjacent infection _Direct inoculation (trauma/surgery) |
S. aureus causes.. (under skin category) | COFS Cellulitis, Osteomyelitis, Furuncles, Septic arthritis Staph-enie always COFS |
SSSS caused by... | Exfoliative Toxin A & B from S. aureus You better exfoliate that skin or you'll be scalded |
SSSS Treatment | Nafcillin |
Nikolsky's sign | Light pressure to skin separates upper epidermis with wrinkling of skin SSSS |
Group A Strep causes... (skin related conditions) | LICE.N Lymphangitis, Impetigo, Cellulitis, Erysipelas, Necrotizing Fasciitis Strep(pers) have Nasty LICE |
M protein | GAS Binds and stabilizes factor H to prevent complement fixation |
Streptokinase | GAS Binds plasminogen to form plasmin GAS with plasmin allows GAS to spread through fibrin |
Streptolysins S & O | GAS Hemolysins contribue to soft tissue damage |
Spe | Streptococcal pyrogenic exotoxins Superantigens _Nec. Fasc, TSS, Scarlet Fever |
Scarlet Fever | GAS |
GAS Treatment | Penicillins usually adequate |
C. perfringens micro | Gram positive, spore-forming, obligatory anaerobic, bacilli "I'm so positively perfect. Don't breath on me" |
C. perfringens Path | Alpha toxin (lecithinase) _lyses RBCs, leukocytes, endothelial cells _tissue destruction, hemolysis, bleeding Beta, Epsilon, lota and an enterotoxin _Iota toxin has necrotic activity & increases vascular permeability |
Alpha toxin | C. perfringens aka lecithinase _lyses RBCs, leukocytes, endothelial cells _tissue destruction, hemolysis, bleeding |
Iota toxin | GAS _Iota toxin has necrotic activity & increases vascular permeability |
C. perf clinical manifestations (skin related) | GM Mega Car (GMMC) are perf(ect) Gas gangrene, Myositis, Myonecrosis, Celulitis |
C. perfringens Treatment | Surgical derbidement Penicillin Can try hyperbaric oxygen |
C. tetani micro | spore former, gram positive, anaerobic bacilli |
C. tetani Pathogenesis | Tetanospasmin - plasmid-encoded, heat-labile neurotoxin |
Tetanospasmin | B binds to lower Goes to CNS via retrograde axonal transport "A" subunit cleaves/inactivates ptns that regulate the release of GABA, so inc. in excitatory NT -Spastic paralysis |
Lockjaw (masseter muscles) tetanus | trismus |
Facial muscle contraction tetanus | Risus sardonicus My face looks like that because someone put Reeses on Sardines |
Back spasms tetanus | Opisthotonos "(O)h, my back. It feels like I (pis)sed tho ton(os)" |
C. tetani Treatment | Surgical debridement Penicillin or metronidazole Tetanus Ig Vaccination |
C. tetani vaccine | Toxoid |
P. aeruginosa Path | ETA Pyocyanin Pyoverdin LasA & LasB |
LasA and LasB | proteases degrade eLAStin |
Pyocyanin | production of superoxide and H2O2 |
Pyoverdin | siderophore |
Pseudomonas Clinical Manifestations | O PUBEES (PseudoMONA was naked and you could see her PUBEES) Osteochondritis, Pneumonia, UTI, Bacteremia, Ecthyma gangrenosum, Ear infections, Skin infections |
Pseudomonas Skin Infections | Burn wounds _vascular damage, tissue necrosis, bacteremia Folliculitis Ecthyma gangrenosum |
Vibrio micro | Comma-shaped gram negative rods Oxidase/catalase + Grow in salt & TCBS |
V. vulnificus | Liver disease patients in particular - Infections of wounds contaminated by salt water • Progressive & severe wound infections • Vesicles form followed by necrosis - Also gastroenteritis after shellfish |
V. parahemolyticus | - Primarily gastroenteritis after shellfish/oysters - Occasionally wound infections |
Pasteurella multocida micro | Gram neg. coccobacilli Grow on blood/choc, not MAC |
Pasteurella multocida Treatment | Penicillin |
Capnocytophaga micro | Filamentous, gram neg rods Grows on blood/choc, not MAC Requires higher CO2 |
Capnocytophaga Treatment | Amoxicillin-clavulanate |
M. marinum from... | wound suffered/contaminated in water |
M. marinum clinical manifestations | Papules on extremity Ulcerate and form scare "Fish tank granuloma" Can have nodular lymphangitis (Sporotrichoid spread) |
Mycobacterium leprae Good CMI | Tuberculoid leprosy (paucibacillary) |
Mycobacterium leprae Poor CMI | Lepromatous leprosy (multibacillary) |
Tuberculoid leprosy | - Localized hypopigmented or erythematous skin lesions - May have nerve involvement with palpable nerves • Sensory loss Low infectivity |
Lepromatous leprosy | - Numerous erythematous lesions of skin - Diffuse nerve involvement with patchy sensory loss - Tissue destruction (often of face/ears) - Leonine facies & saddle nose - Infectivity is high |
Tuberculoid leprosy Treatment | • Dapsone & Rifampin x6-12 months |
- Lepromatous leprosy Treatment | • Dapsone, Rifampin & Clofazimine x2 years |
- Dapsone | • Interferes with folic acid synthesis (PABA antagonist) |
- Clofazimine | • Binds to guanine bases in DNA • May cause hyperpigmentation & phototoxicity |
Malassezia furfur Micro | Requires olive oil (FAs) to grow Can grown on blood agar or fungal agars (potato dextrose agar) with olive oil |
Potato dextrose agar | Malassezia furfur |
Malassezia furfur | |
Malassezia furfur "Spaghetti and meatballs" | |
Malassezia furfur Clinical Man. | Tinea (Pityriasis) Versicolor _Hypo/Hyperpigmented macules on upper body usually Asymptomatic otherwise – rare pruritis Occasionally TPN (Total Parenteral Nutrition)-related sepsis _Lipids in TPN promote growth of yeast |
Malassezia furfur Treatment | Topical azoles Selenium sulfide |
Malassezia furfur | |
Malassezia furfur | |
Dermatophytes Treatment for localized and not affecting hair or nails | Topical (azoles, terbinafine) |
Dermatophytes Treatment affecting hng hair, nails, groin or diffuse | Oral agents (griseofulvin, terbinafine, azoles) Hair is full of grease (griseofulvin) |
Dermatophyte Tinea barbae | |
Dermatophyte onychomycosis (Tinea unguium) | |
Dermatophyte Tinea corporis | |
Dermatophytes invade.. | skin, hair & nails – keratinophilic & keratinolytic Primarily involve stratum corneum |
Dermatophytes H&E biopsy | |
Sporothrix schenckii | |
Sporothrix schenckii (Donald Trump size hands) | |
Sporothrix schenckii Micro | Dimorphic fungus Ubiquitous in soil & vegetation Daisy/floret-like conidia as mold in culture at 25ºC Cigar-shaped (and oval) yeasts in tissue |
Sporothrix schenckii Clinical Man. | “Rose-gardener’s disease” Nodule at site of inoculation (+/- ulceration) Nodules form along lymphatic channels ~2 weeks later |
If you see "Sporotrichoid spread", think... | S. schenckii, M. marinum, & Nocardia |
Sporothrix schenckii Treatment | Potassium iodide Itraconazole often used instead |
Ancylostoma braziliense | |
Ancylostoma braziliense | |
Ancylostoma braziliense Epidemiology | Widespread Often children in contact with feces-contaminated soil/sand Larvae penetrate intact skin |
Ancylostoma braziliense Clinical Man. | Pruritis Erythematous or vesicular reaction to serpentine tunnels |
Ancylostoma braziliense Treatment | Albendazole or Ivermactin |
Dracunculus medinensis Epidem. | Isolated areas in Africa |
Dracunculus medinensis Transmission & Life Cycle | *Larvae in water infect small crustaceans *Ingestion of unfiltered water may contain crustaceans *Larvae released in stomach & small bowel *Get into abdominal cavity & retroperitoneum where they mate *Males die, females move to subcutis & release larvae *Forms blister on skin which ruptures |
Dracunculus medinensis Clinical Man. | Painful ulcer with emergence of worm Gross... |
Dracunculus medinensis Treatment | Remove the worm. Duh. |
- Dracunculus medinensis | |
Trichinella spiralis Epidem. | Worldwide, including US Associated with pork consumption (haram!) |
Trichinella spiralis Life Cycle | *Pigs contain adult worms & encysted larvae *Humans ingest encysted larvae in undercooked meat *Larvae develop into adults in small intestine *After mating, females release larvae *The released larvae get into blood stream and lodge in muscle *Can get cardiac, CNS, lung involvement |
Trichinella spiralis Clinical Man. | Periorbital & facial edema, conjunctivitis Fevers, myalgias & weakness Rarely myocarditis, CNS involvement & pneumonitis Eosinophilia |
Trichinella spiralis Treatment | Albendazole |
Trichinella Spiralis |
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