Question | Answer |
Anesthetic MOA | small sensory fibers selectively blocked (shorter distance, longer action potl); mem-stabilizing drugs (dec rate of depolarization); block Na influx |
Order of loss of nerve fn with anesthetic | Loss of pain, temperature, touch, proprioception, and then skeletal muscle tone. |
Anesthetic: order of fibers blocked | small, slow, unmyelinated first; C-fibers (pain) before A fibers (motor); unprotonated molecule passes into nerve |
Esters = | Procaine (Novocaine) (dental); Benzocaine (Americaine) (topical); Cocaine; prone to cause “allergic” rxn; metabolized by pseudocolinesterases |
Amides = | Lidocaine (Xylocaine) (peripheral infiltration); Bupivacaine (Marcaine) (long acting peripheral infiltration); metabolized in liver |
Local anesthetic: tox: early neuro sx | lightheaded/dizzy, visual disturbance, tinnitus |
Local anesthetic: tox: late neuro sx | peri-oral numbness, mx twitches/ tremors, seizure |
Local anesthetic: tox: cardiac sx | Hypotension (vasodilation), cardiac arrhythmia |
Use punch biopsy for: | all pigmented lesions |
Excisional biopsy | Fusiform excision. Length to width ratio of 3:1 & angles in the corners should be ≤ 30 degrees |
Suture for soft tissue lesions | inverted mattress |
Most common, benign epithelial skin tumor = | Seborrheic keratosis |
Seborrheic keratosis: common locations | Predilection toward face, trunk, and extremities |
Single or multiple, discrete, dry, rough, adherent scaly lesions = | actinic keratosis |
Actinic keratosis: Tx | skin bx / excision; liquid N2; topical 5% 5-FU cream |
Skin ca | BCCA 90% of all skin ca; SCCA more aggressive |
Skin ca: Tx | excision w/ > 0.3cm radial margins; Mohs micrographic surgery; radiation therapy |
Melanoma Tx | punch/excision bx (NOT shave bx); wide local excision with 1-2 cm radial margins; specimen including all subQ tissue down to fascia; refer pt to surg oncologist? |
Do not close a wound that is: | >24 hrs old |
Absorbable suture (Vicryl) utilized where: | below the skin, inside mouth, or where suture removal is difficult |
Use non-absorbable suture where: | in most skin closures |
Staples may be used for: | scalp, trunk, some extremity wounds |
Suture size: | 5-0 or 6-0 face, 3-0 or 4-0 on trunk or extremity |
Pt w/tetanus-prone wounds (>6 hrs old, contaminated, devitalized) should receive: | tetanus toxoid if last booster was >5 yrs before injury; tetanus toxoid plus tetanus Ig if no prior vax |
Pts w/ non-tetanus-prone wounds should receive: | tetanus toxoid alone if last booster was >10 yrs ago |
Dirty wounds (or >8 hrs old) should be: | thoroughly debrided and allowed to heal by secondary intention |
Puncture wounds should be considered: | dirty (stab, bullet) |
Defn Abscess: | localized collections of pus; fluctuant (soft, fluid-like) or indurated (hard) (if cellulitis) |
Defn Boils | staph infections of follicular or sebaceous glands |
Defn Furuncles | acute, single-loculated abscesses; may suppurate & necrose or regress / be reabsorbed (warm, moist compresses may quicken localization of small abscesses) |
Defn Carbuncles | larger, often multi-loculated abscesses, which usually require I&D |
Paronychias: | occur at the nail base due to trauma |
Felons: | abscesses of the pulp of the finger |
Animal bites: tx | Wounds should be left open initially; broad-spectrum Abx; rabies watch |
Pigmented lesions: look for: | Asymmetry; Borders (irregular); Color (variegated); Diameter (increasing) |
Local anesthetic: | topical or intradermal/subcutaneous infiltration at the wound site |
Field block: | infiltration of local anesthetics circumferentially around the wound; for irregular wounds or in areas w/thin or difficult-to-handle skin |
Peripheral nerve block: | injection of local anesthetics adjacent to appropriate peripheral nerve (usually digital) |
tetanus prophalaxis for a tetanus prone wound, never immunized previously or unknown | tetanus toxoid plus tetanus immune globulin at separate site |
tetanus prophalaxis for a non-tetanus prone wound, last booster >10 years ago | tetanus toxoid alone |
infection of hair follicle cuased by obstruction | furuncle |
infection of the terminal phalanx or pulp of the finger | felon |
infection involving the subepithelial folds of tissue around the nailbed | paronychia |
technique for fusiform excision | length to width ratio of 3:1 with corner angles at approximately 30 degrees |
most common benign epithelial skin tumor | seborrheic keratosis |
most common type of skin cancer | basal cell carcinoma |
characteristic appearance of a basal cell carcinoma | pearly lesion |
treatment for all pigmented lesion | punch biopsy or excision biopsy |