ASDS Quest Questions Flashcards
Which branch of CN VII classically innervates the corrugator supercilii muscle?
Temporal branch
What is the recommended maximum dosage of lidocaine when used in tumescent anesthesia for liposuction?
55 mg/kg
What 3 proteins make up the SNARE complex?
SNAP-25, Synaptobrevin, and Syntaxin
What are the name of the small fibrous attachments between the periosteum and bone?
Sharpey’s fibers
Medium depth chemical peels traditionally cause injury to what level of the skin?
Papillary to upper reticular dermis (0.45 mm)
Which division of the ophthalmic branch (V1) of the trigeminal nerve is responsible for sensory innervation to the tip of the nose?
External nasal branch (of the Anterior Ethmoidal nerve)
Methemoglobinemia associated with use of prilocaine can be treated with what?
Methylene blue or ascorbic acid (Vitamin C)
What are the recommended lengths for contraception in both males and females after treatment with vismodegib?
2 months for males and 7 months for females
Mutations in which gene have been associated with aggressive, metastatic ocular melanomas?
BAP-1
Gold handles, like those seen in the image shown, indicate what about an instrument?
Tungsten carbide pads are used in the area which grasps the needle, improving grip on the needle and longevity of the instrument
Which sterilization method carries the lowest risk for corrosivity/dulling of sharp instruments?
Dry heat (oven)
Upon administration of anesthesia, loss of sensation or function occurs in what order?
Temperature, pain, touch, pressure, vibration, propioception, motor function
Which newer chemical sterilant sterilizes immersed instruments more quickly (10-15 minutes), shows increased activity against mycobacteria and spores, but can stain the skin gray with use?
Ortho-phthalaldehyde
All available botulinum toxins fall into what pregnancy category?
C
What does the nail bed dermis sit directly on top of?
Periosteum
What is the only anesthetic where addition of epinephrine has no effect on onset or duration?
Ropivicaine
The instrument shown is particularly useful in what scenario?
Allis hemostats, good for grasping wall of cysts without puncture
Name two preservatives in amide anesthetics that can cause local allergic reactions.
Sodium metabisulfite and Methyl-paraben
The instrument shown in an example of what type of scissor?
Metzenbaum scissor (handle longer than blade; contrast with Mayos which have 1:1 blade:handle ratio)
The instrument shown is?
Double-action nail cutter
Trigeminal Trophic Syndrome is often the result of damage to CN V at which particular site?
The Gasserian ganglion (may be due to encephalitis, leprosy, or some other form of nervous injury)
Which sterilization method is known to not always be effective against bacterial spores and Hepatitis B, and as such is not considered adequate for sterilizing surgical instruments?
Cold sterilization/chemical immersion
Which nerve branch is responsible for the clinical finding known as Hutchinson’s sign?
External nasal branch (of anterior ethmoidal nerve)
What are the ingredients of the Baker-Gordon phenol peel (include amounts of each ingredient)?
Phenol 88% (3mL), Distilled water (2mL), Septisol liquid soap (8 drops), Croton oil (3 drops)
All botulinum toxins are effectively proteases that cleave any of a collection of proteins in the presynaptic neuron. This collection of proteins is known as what?
The SNARE complex
Which division of cranial nerve V provides sensory innervation to the lower eyelid?
V2 (Maxillary division)
What are the symptoms of lidocaine toxicity, in order of increasing serum lidocaine levels?
Circumoral paresthesia, tinnitus, visual disturbances, seizures, coma, cardiopulmonary arrest.
Which currently FDA approved botulinum toxin has lactulose as an added ingredient?
Dysport® (but still safe to use in lactose intolerant patients)
The instrument shown is?
Hair transplant scalpel handle (meant to hold multiple blades)
What topical antibacterial agent inhibits bacterial protein synthesis by interacting with Protein L3 on the 50S subunit of the bacterial ribosome?
Retapamulin (Altabax)
Which form(s) of electrosurgery are examples of direct current?
Electrocautery, electrolysis
Which non-absorbable suture has the highest risk of infection?
Silk
Use of which topical antibacterial agent has been reported to cause neural deafness in neonates?
Neomycin
Which pharyngeal arch gives rise to the muscle of mastication?
The mesoderm of the first pharyngeal arch
The instrument shown in an example of what type of scissor?
Spencer suture scissor
What commonly prescribed medications can increase plasma lidocaine levels?
Beta-blockers
What is the mechanism of action of topical gentamycin?
Binds the 30S subunit of the bacterial ribosome, causing misreading of mRNA, inhibiting bacterial protein synthesis
Which nerve from the cervical plexus supplies sensory innervation to the anterior and posterior lobule of the ear as well as the skin overlying the mastoid process?
Great auricular nerve (of C2 and C3)
Needle drivers with a tip as shown are particularly useful in what scenario?
When operating alone (Olsen drivers combine needle driver and suture scissor, improving efficiency)
Compared to botulinum toxin serotype A, serotype B has a faster or slower onset of action?
Faster (but also wears off faster as well)
Serotype B → MyoBloc
CO2 “slush” is a physical superficial peeling agent that is formed by dipping the tip of a cone of dry ice into what solution and then applying to the skin?
A 3:1 mixture of alcohol:acetone
Which antiseptic agent has the broadest antimicrobial spectrum?
Povidone-iodine
The instrument shown is?
Nail-pulling forcep
Which muscles of the eye are not innervated by cranial nerve III?
Lateral rectus (CN VI) and superior oblique (CN IV)
LR6 and SO4
What substances, acting as stabilizers, can be added to mass-produced botulinum toxins?
Sucrose and lactulose
Smoothened (Smo) allows what signaling molecule to enter the nucleus and lead to proliferative effects?
Gli
A fingernail grows from the matrix to the distal free edge over what period of time?
4-6 months
Which three antiseptic agents exert their mechanism of action by disrupting microbial cell membranes?
Hexachlorophene, Chlorhexidine, and Triclosan
Which form(s) of electrosurgery are both low voltage and low amperage?
Electrolysis
Which, if any, of the neurotoxins currently FDA approved are free from complexing protein?
Incobotulinumtoxin A (Xeomin)
What is the most commonly used medication and dosing regimen for HSV prophylaxis when performing medium depth and deep chemical peels?
Valacyclovir 500mg PO BID beginning one day prior to the procedure, continuing for 10-14 days (valacyclovir 1g once daily can also be used)
What is the name of the perforating vessels that connect the great saphenous vein to the deep (posterial tibial) veins of the lower leg?
Cockett perforators
Botox® was first FDA approved for what indication?
Blepharospasm
What is the recommended maximum dosage of lidocaine in children, both with and without epinephrine?
- 1.5-2 mg/kg without epinephrine
- 3-4 mg/kg with epinephrine
What is the appropriate plane of undermining when performing dermatologic surgery or reconstruction in the area of the temple?
Superficial subcutaneous fat ABOVE the SMAS (the temporal branch of CN VII lies within or immediately deep to the SMAS in the superficial fascia in the area of the temple, making it particularly susceptible to injury, as this branch arches over the lateral brow it dives deep to the frontalis muscle, which protects it from injury)
Which 4 histologic characteristics have been established as “high-risk” features by the American Joint Committee on Cancer, and may upstage a cutaneous SCC from Stage I to Stage II?
Poor differentiation, perineural invasion, Clarks level IV, depth of invasion >2mm
Botulinum toxin serotype B (BTX-B) cleaves which protein within the SNARE complex?
Synaptobrevin (serotypes D, F, and G also cleave synaptobrevin)
Which nerve is particularly susceptible to injury with retroauricular surgery in pre-pubescent patients?
The facial nerve (CN VII), which exits the stylomastoid foramen. In adults, the nerve is protected by the mastoid and its air spaces, but these are not fully developed until puberty.
Nerve injury as a result of dermatologic surgery over the mid-mandible is a direct result of injury to which branch of the facial nerve? What clinical signs result from this injury?
Injury to the marginal mandibular branch of CN VII (not to be confused with the V3-Mandibular branch of CN V) as it passes over the mandible results in drooping of the corner of the mouth.
What nerve innervates this area of the foot?
Lateral plantar nerve (terminal branch of posterior tibial nerve)
When does fingernail development begin?
Embryologic week 10
Lidocaine is falls into what pregnancy category? What if you add epinephrine?
B (addition of epinephrine to lidocaine increases risk to category C)
The tip in the image shown is seen in what specific type of needle driver?
Olsen needle drivers (combines scissor just proximal to needle-grasping tip)
Hyaluronidase can be added to local anesthetics to increase diffusion. What contact allergen is contained within hyaluronidase such that a skin test is recommended prior to use?
Thimerosal
Keratoacanthomas in which two anatomic locations are known to be unlikely to regress spontenously?
Mucosal and subungual lesions
Which two genes are the most commonly mutated in malignant melanomas?
BRAF (60%) and NRAS (30%)
What temperature is required for destruction of a malignant lesion with LN2?
-50°C
What substance can be added to mass-produced botulinum toxins to prevent adhesion of the neurotoxin to the glass of the vial?
Human serum albumin
Which systemic treatments are most widely used for syndromic variants of keratoacanthoma?
Retinoids (MTX, 5-FU, and cyclophosphamide are also used, but retinoids are most common due to a better side effect profile)
Which keratoacanthoma variant is characterized by the sudden appearance of hundreds to thousands of small (2-3 mm) disseminated KAs which are distributed in both sun-exposed and sun-protected areas and is diagnosed during adulthood?
Gryzbowski variant
The needle curvature most commonly used in dermatologic surgery?
3/8 circle
What nerve innervates this area of the hand?
Radial nerve
What are the most commonly used gases for gas sterilization?
- Ethylene oxide → most common
- Formaldehyde
EMLA should not be used in children less than what age to prevent methemoglobinemia?
3 months
Due to prilocaine toxicity
Split nails that are visible usually occur due to biopsy of what portion of the nail?
Proximal nail matrix
A toenail grows from the matrix to the distal free edge over what period of time?
1-1.5 years
What is the name of the topical Smoothened inhibitor currently under investigation for treatment of BCC?
LDE 225
Which branch of CN VII supplies the occipitalis muscle?
Posterior auricular nerve
(Important to note that this branch is not classically included in the “To Zanzibar By Motor Car” pnemonic)
The property that quantifies how easily suture passes through tissue?
Coefficient of friction
Botulinum toxins are subdivided into how many different serotypes?
7 (A → G)
What are the ingredients of Jessner’s solution (include amounts of each ingredient)? (4)
Salicylic acid (14g), Lactic Acid (14g), Resorcinol (14g) all compounded in 95% Ethanol
With which superficial peeling agent is the expected post-peel response a slightly yellow discoloration?
Tretinoin 1%
Which division of the mandibular branch (V3) of the trigeminal nerve supplies sensory innervation to the tragus?
Auriculotemporal nerve
Which topical antibacterial agent can cause mast cell degranulation, and is therefore contraindicated in patients with mastocytosis?
Polymyxin B
An injury to which motor branches of cranial nerve VII can be temporary?
Zygomatic and Buccal since both nerves have extensive rami and cross innervation
Which of the ingredients of the Baker-Gordon phenol peel are most important for efficacy (i.e., depth) of the peel?
Croton oil → keratolytic component that leads to penetration of peel solution
Which muscle of facial expression is primarily responsible for smile formation?
Zygomaticus major (and to a lesser extent, the zygomaticus minor as well)
CN VII emerges from the skull base at which specific location?
Stylomastoid foramen
What is the boiling point of LN2?
-195.8°C
Superficial chemical peels traditionally cause injury to what level of the skin?
Epidermis to papillary dermis (0.06 mm)
Which form of electrosurgery works in a wet field?
Electrocautery
What are the two most commonly used agents for neutralizing a glycolic acid peel?
Saline or 5-10% sodium bicarbonate solution
The ability of a suture to regain its original form and length after deformation?
Elasticity
The instrument shown in an example of what type of scissor?
Gradle scissors
Which class of medications may diminish the effect of neurotoxins?
Cholinesterase inhibitors (e.g., certain Alzheimer medications like donepezil and rivastigmine, myasthenia gravis medications, and insecticides)
Which one of the components of the commonly used triple-antibiotic ointment (neomycin/bacitracin/polymyxin B) is most likely to cause allergic contact dermatitis in users?
Neomycin
Cyanoacrylate is also known as?
Dermabond
The instrument shown in an example of what type of scissor?
Mayo scissor (blade to handle ratio nearly 1:1; contrast with Metzenbaum scissor, which has much longer handle than blade)
Lid ptosis associated with botulinum toxin injection can be corrected with use of what?
Apraclonidine (Iopidine) drops can be used t.i.d., this α2 adrenergic agonist stimulates contraction of Muller’s muscle (phenylephrine also reported effective)
The instrument shown is?
Allis clamp/hemostat
The protease action of botulinum toxin is dependent upon what element?
Zinc
Which antiseptic agent has been shown to cause hypothyroidism in neonates with chronic maternal use?
Povidone-iodine (Iodoform)
Myobloc® is currently FDA approved for what indication?
Cervical dystonia (torticollis)
Which non-absorbable suture has the highest tensile strength?
Steel (if steel is not an option, look for polyester)
The type of blade handle shown is?
Bard-Parker #3
What symptom of lidocaine toxicity is first to appear?
Circumoral paresthesia
The instrument shown is?
Nail elevator
What type of coating is added to absorbable sutures with a “plus” connotation (e.g. Polyglactin 910 Plus)?
Triclosan (antibacterial agent)
The blade shown here, which is used most commonly for large excisions and on areas of thick skin, is sharpest at what portion of the blade?
The belly (blade shown is a 10-blade)
Which specific protein produced by HPV inhibits p53 function and has been linked to development of SCC?
HPV E6 protein
Which anesthetic has the shortest duration of action?
Prilocaine
Use of which topical antimicrobial agent can lead to SJS/TEN in sulfa-allergic patients?
Silver sulfadiazine
Which form of electrosurgery is least damaging to the affected tissue?
Electrofulguration
Which antiseptic agent is a known teratogen and is neurotoxic in infants?
Hexachlorophene (Phisohex)
Name 4 genes that have been shown to be important in susceptibility to basal cell carcinoma.
TP53, PTCH1, PTCH2, and SUFU
What is the boiling point of solid CO2/dry ice?
-78.5°C
Efficacy of photodynamic therapy is dependent upon intracellular accumulation of what porphyrin prior to UV exposure?
Protoporphyrin IX
Which nerve from the cervical plexus provides sensory innervation to the anterior portion of the neck?
Transverse cervical nerve (C2, C3)
Also known as superficial cervical nerve
Which antiseptic agent has been reported to cause neuropathic symptoms in the fingertips of surgeons with consistent use?
Hexachlorophene (Phisohex)
Use of which topical antibacterial agent over large areas of body surface, especially in burn patients, has been reported to lead to nephrotoxicity?
Mupirocin (Bactroban)
If Baker-Gordon phenol peel solution were to enter the eye, what should it be flushed with?
Mineral oil
You need to use a lipid solution, NOT water.
Nerve block of the median nerve at the dorsal wrist involves injection between which two tendons?
Palmaris longus (medially and flexor carpi radialis (laterally)
Which topical antibacterial agent interacts with phospholipids in bacterial cell membranes, increasing cellular permeability?
Polymyxin B
Cutaneous SCC developing in areas of chronic inflammation or scarring (e.g. discoid lupus, hypertrophic lichen planus) are associated with metastasis in approximately what percentage of cases?
30-40%
Which type of needle tip is least likely to cut through tissue?
Taper
What are the two most commonly reported side effects when botulinum toxin is injected for cosmetic indications?
Headache and ptosis (lid ptosis is correctable, brow ptosis one must wait for toxin effect to wear off)
True or false: the muscles of facial expression of the lower face have bony insertions
False
What nerve innervates this area of the foot?
Saphenous nerve
What is the mechanism of action of topical 5-fluorouracil in the treatment of cutaneous neoplasms?
It is a pyrimidine antagonist, which blocks conversion of dUMP to dTMP in the synthesis of DNA and RNA through inhibition of thymidylate synthetase.
What are the dermoscopic buzz words often associated with BCC?
“Spoke wheel pigmentation” and “maple leaf structures”
Which absorbable suture has the highest initial tensile strength?
Poliglecaprone 25 (Monocryl)
What is the one-year risk of progression to primary SCC of any individual actinic keratosis?
0.075-0.24%
Effectively, less than 0.1-0.2%
Mutations in which gene are commonly seen in Spitz nevi and not seen in malignant melanomas?
HRAS
Non-melanoma skin cancer has been shown to behave more aggressively in patients with what type of leukemia?
CLL
Which portion of the chemical structure of anesthetic molecules determines the onset of activity?
Aromatic end (lipophilic)
Greater lipid solubility enhances potency and onset of anesthesia through more rapid diffusion across cell membranes
The instrument shown is?
Crile-Wood needle driver
Useful for larger needles → notice longer handle and larger jaws than Webster needle driver (pictured)
What are the most commonly used settings for the dry heat/oven sterilizer?
60 minutes at 171°C or 6 hours at 121°C.
The type of blade (number) shown here is most commonly used in what body areas?
The 15c blade is most commonly used in confined areas/tight spaces with thin skin (e.g., periorbital, conchal bowl)
The instrument shown in the image is?
Lister bandage scissors
Of the two forms of arsenic commonly found in ground water (which has been shown to be associated with an increased risk of cutaneous SCC), which is more toxic?
Arsenite (it is 300x more toxic than the other form, arsenate)
Though very rare, metastases with BCC tend to occur in which two locations?
Lymph nodes and lungs
Ester anesthetics may cross react with which substances?
Sulfa, thiazides, parabens, paraphenylenediamines
(STPP)
Which two subtypes of HPV are most commonly associated with subsequent development of cutaneous SCC?
HPV 16 and 18
What is the name of the perforating vessels that connect the great saphenous vein to the deep (femoral) veins of the leg at the level of the knee?
Boyd perforators
The instrument shown is?
Kelly clamp
Note larger tip than what is seen with Halsted hemostats (pictured)
Why is prior radiation to the head and neck AN important piece of medical history to obtain prior to chemical peeling?
Radiation to the head and neck decreases the number of pilosebaceous units in treated areas (much like isotretinoin), this delays wound healing after peeling and increases the risk for abnormal scarring.
HSV reactivation has been shown to occur when performing which types of chemical peels?
Medium depth and Deep (because of this risk ALL patients regardless of HSV history are required to have HSV prophylaxis with medium and deep chemical peels)
Which component of Jessner’s solution has been shown to rarely cause exogenous ochronosis?
Resorcinol
(Remember Jessner’s solution → resorcinol, salicylic acid, lactic acid and fill to 100 mL with ethanol)
The three portions of a surgical needle are?
Tip, body, and shank (or swage)
Strongest part of needle is the body
The instrument shown is?
Nail splitter
A mutation in which gene has been associated with a predisposition to develop malignant melanoma?
CDKN2A
Which anesthetics are pregnancy category C, and what is the most feared complication in the fetus when these anesthetics are used?
Bupivicaine and Mepivicaine, fetal bradycardia is the feared side effect.
True or false: The nail matrix lacks a granular layer
True
What are the four chemicals required in the Chemiclave (chemical autoclave)?
Formaldehyde, methyl ethyl ketone, acetone, alcohols
What is the final concentrationof lidocaine and epinephrine in .05% solution for tumescent anesthesia?
0.05% lidocaine and 1:1,000,000 epinephrine
(Always has 1:1,000,000 epinephrine)
What is the most common anatomic location for arsenical melanosis?
Upper back and chest
NOT acral as is commonly thought
What vascular finding is classically found on dermoscopy of SCIS/Bowen’s disease?
Glomerular vessels
What vascular finding is classically found on dermoscopy of SCIS/Bowen’s disease?
Glomerular vessels
Which branch of CN VII classically innervates the procerus muscle?
Zygomatic branch
(Note the corrugator supercillii are innervated by temporal branch)
What oral medications have proven effective in the chemoprevention of cutaneous malignancies?
Vitamin A/Retinoids (e.g., isotretinoin in patients with xeroderma pigmentosum has been shown to decrease skin cancer incidence by up to 63%)
How much time must elapse after injection for maximal vasoconstriction due to epinephrine to occur?
7-15 minutes
The instruments shown is an example of what type of forcep?
Brown-Adson forceps (notice the peripheral row of teeth along the edges not seen in Adson forceps)
Silver sulfadiazine, when used over large areas of body surface, can lead to leukopenia. Concomitant use of what medication increases the risk for this complication?
Cimetidine
What are the most commonly used settings for the steam autoclave cycle?
20-30 minutes, 2 atm (or Pascals) of pressure, at 121°C
Which nerve is susceptible to injury in cutaneous surgeries involving the lateral upper leg?
Common peroneal nerve → as it wraps around head of fibula
Patients with basal cell nevus syndrome are known to be at increased risk to develop what two intracranial tumors?
Medulloblastoma and meningioma
What nerve innervates this area of the hand?
Radial nerve
Nerve block of the entire plantar surface of the foot includes blockade of which 3 nerves? At which 3 locations?
Posterior tibial nerve (immediately behind medial malleolus), sural nerve (immediately behind lateral malleolus), and the saphenous nerve (just above the medial malleolus)
Note the tibial nerve terminally divides into medial plantar and lateral plantar nerves
Which of the antiseptic agents must air dry in order to be bactericidal?
Povidone-iodine
The trigeminal nerve provides motor innervation to which group of muscles? (4)
Muscles of mastication
- Masseter
- Temporalis
- Medial and lateral pterygoids
Which absorbable suture has the highest knot security of all synthetic absorbable sutures?
Poliglecaprone 25 (Monocryl)
Which form of electrosurgery is the most dampened of the biterminal devices?
Electrocoagulation
What nerve innervates this area of the foot?
Calcaneal nerve (branch of posterior tibial nerve)
Which nerve providing sensory innervation to the sole of the foot is the only one to be derived from the femoral nerve more proximally in the lower extremity?
Saphenous nerve
All other sensory nerves to the sole are derived from the sciatic nerve
What gene is the most commonly mutated in BCC?
PTCH1 mutations are present in 2/3 of BCC (p53 mutations are 2nd most common, seen in approximately 50% of BCC)
The instrument shown is?
LaGrange scissors
LaGrange scissors are strange
Used for fine tissue trimming or suture cutting and HAIR TRANSPLANTATION to harvest donor site grafts
What is the only serotype of botulinum toxin to cleave Syntaxin?
Botulinumtoxin C
What are some medical co-morbidities that are contraindications to using epinephrine in local anesthetics?
Pheochromocytoma, uncontrolled hyperthyroidism, acute angle glaucoma, severe HTN or PVD
The propensity of suture to return to or to maintain its natural configuration?
Memory
Which nerve from the cervical plexus supplies sensory innervation to the upper posterior auricle and the scalp posterior to the upper ear?
Lesser occipital nerve (C2)
Which three nerves are known to exit at Erb’s point along the posterior sternocleidomastoid?
CN XI (spinal accessory), lesser occipital (C2), great auricular (C2, C3)
What nerve innervates this area of the hand?
Median nerve
Which division of the ophthalmic branch (V1) of the trigeminal nerve is responsible for sensory innervation to the conjunctiva?
Lacrimal nerve
Which antiseptic agent has been reported to cause keratitis?
Chlorhexidine gluconate
What is the purpose of povidone when added to iodine in antiseptic solutions?
It acts a solubilizing agent
What are the most commonly used solutions for cold sterilization/chemical immersion?
Glutaraldehyde or aqueous formaldehyde
When does toenail development begin?
Embryologic week 14
Note that fingernail development starts at embryologic week 10
Describe the clinical signs associated with each of the three level of frosting that can be seen with TCA peels.
- Level I → erythema with streaky white areas of frosting
- Level II → nearly uniform white enamel coloring but with visible erythematous background
- Level III → solid white enamel frosting with no visible erythema (this signifies penetration to the reticular dermis)
What is the first unit component of the nail unit to be recognized during the embryologic period?
Hyponychium
Which muscle, sometimes referred to as a muscle of mastication, is supplied by CN VII?
The buccinator muscle (this muscle is not classically referred to as one of the four muscles of mastication, which are actually all innervated by CN V, it “assists” in mastication by keeping food pushed toward the occlusal surface of the posterior teeth during the act of chewing).
What types of medications can affect lidocaine metabolism?
CYP450 3A4 inhibitors
E.g., macrolides (clarithromycin, erythromycin), -azoles, calcium channel blockers (verapamil, diltiazem)
Knot strength is directly proportional to which other suture property?
Coefficient of friction
Abobotulinumtoxin A is more commonly known by what name?
Dysport
Which preservative in anesthetics cannot be used in infants with hyperbilirubinemia?
Methyl paraben (methyl paraben displaces bilirubin from albumin, making hyperbilirubinemia worse)
Which antiseptic agent has the fastest onset of action?
Isopropyl alcohol
Mupirocin’s mechanism of action is tied to reversible binding to what bacterial protein?
Isoleucyl tRNA synthetase
What is the metabolite of Prilocaine that can lead to methemoglobinemia?
Orthotoluidine (metabolizes hemoglobin → methemoglobin)
The frosting seen with TCA peeling is due to what?
Keratocoagulation and precipitation of denatured proteins (this is in contrast to the “frosting” noted with salicylic acid peels, which is due to precipitation of salicylic acid crystals)
Which superficial peeling agent is safe for use in pregnancy and while breast feeding?
Glycolic acid (salicylic acid peels are not recommended in these patients due to risk of salicylism)
What sterilization method can lead to allergic contact dermatitis in practitioners?
Cold sterilization/chemical immersion (primarily due to glutaraldehyde sensitivity)
Which antiseptic agent is a biguanide?
Chlorhexidine gluconate
Where is the primary location for drainage of the facial veins?
Cavernous sinus (and less so, the internal jugular vein)
What nerve innervates this area of the foot?
Medial plantar nerve (a terminal branch of the posterior tibial nerve)
Frey’s syndrome (gustatory sweating) is classically associated with damage to which nerve?
Auriculotemporal nerve, a branch of CN V3
Can arise after parotid gland surgery due to attachment of auriculotemporal nerve endings to sweat glands in same region
If after a medium-depth peel, despite adequate prophlaxis with valacyclovir 500mg BID, HSV reactivation is suspected, the antiviral regimen should be changed to what?
Valacyclovir 1000 mg TID
Which division of the mandibular branch (V3) of the trigeminal nerve usually runs alongside the superficial temporal artery?
Auriculotemporal nerve
Remember the auriculotemporal nerve is a branch of CN V3!
Which topical anesthetic carries the highest risk of allergic contact dermatitis?
Benzocaine
Frey’s syndrome is classically associated with what 3 symptoms?
Pain, vasodilation, and diaphoresis of the lateral cheek (during or immediately prior to eating)
Which anesthetics have the longest duration of action?
Bupivicaine, Etidocaine, Ropivicaine, and Tetracaine (longest duration without epi is Ropivicaine, longest duration with epi is Bupivicaine)
What is the recommended maximum dosage of bupivicaine?
175 mg (NOT weight based)
What depth of invasion has been shown to be associated with an increased risk of metastases in cutaneous SCC?
4 mm or more
What nerve innervates this area of the hand?
Median nerve
Which portion of the chemical structure of anesthetic molecules binds to sodium channels on axons?
Amine end
This also determines duration of action
Remember the aromatic end determines onset of action and potency
Topical imiquimod modifies local immune response through which Toll-like receptors?
TLR-7 primarily (to a lesser extent, TLR-8)
Which nerve is thought to be responsible for the majority of the sensory fibers supplying the conchal bowl?
Auricular branch of vagus nerve (CN X)
Injury to the spinal accessory nerve (CN XI) at Erb’s point causes what classical clinical finding?
A winged scapula (CN XI provides motor innervation to both the trapezius and the sternocleidomastoid, as such inability to elevate the shoulder, inability to initiate shoulder abduction, and chronic shoulder pain can also be seen)
What skin disorder is characterized by pustules, erosions, and crusting in areas of alopecia which tend to be atrophic or actinically damaged, often after trauma or treatment of actinic keratoses (e.g. PDT, topical immunotherapy)?
Erosive pustular dermatosis of the scalp
Bacitracin impedes bacterial cell wall synthesis by forming a complex with what component of the bacterial cell wall?
C55 phenol pyrophosphate
The instrument shown is?
Westcott scissor (spring loaded, curved tips, useful for perioribital and conjunctival surgery)
What is the recommended maximum dosage of lidocaine in adults, both with and without epinephrine?
7.0 mg/kg with epinephrine, 4.5 mg/kg without epinephrine
See below sample calculation
Note: 1% lidocaine has 10 mg of lidocaine per 1 mL
What nerve innervates this area of the foot?
Deep peroneal (fibular) nerve
What is the mechanism of action of ingenol mebutate?
The exact mechanism is unknown, however it is known that the medication leads to immediate cell necrosis (not apoptosis) as well as increases inflammatory cell response at the site of application.
Used to treat actinic keratoses
Which anesthetic is most associated with cardiotoxicity?
Bupivicaine
If bupivicaine is not an option, look for ropivicaine, which is also cardiotoxic
Which common component of sunscreens is a metabolite of ester anesthetics?
PABA
Uveal melanomas and blue nevi have been associated with mutations in which gene?
GNAQ
Which portion of the chemical structure of anesthetic molecules allows for diffusion into axonal membranes?
Aromatic (also determines speed of onset)
Topical imiquimod has been rarely reported to cause eruptions of what benign cutaneous neoplasm?
Epidermal inclusion cysts (Cyclosporine can rarely lead to this effect as well)
Which of the named facial vessels are derived from the ICA?
The supratrochlear, supraorbital, palpebral, dorsal nasal, and lacrimal arteries (all are branches of the larger ophthalmic artery)
What is the antimicrobial mechanism of action of povidone iodine?
Oxidation and substitution of microbial cell components by free iodine…it directly halogenates microbial proteins to form salts.
Local anesthetics preferentially effect which types of nerve fibers?
C-fibers and A-delta fibers
Pain and temperature preferentially blocked
Topical retinoids have been shown to accelerate healing after chemical peels, but must be stopped how long prior to the peeling procedure to ensure an intact epidermal surface at the time of the peel?
Stop topical retinoids 2-3 days prior
Restart topical retinoids once erythema has subsided → usually 2-3 days for superficial peels and up to 4-6 weeks for medium depth peels
CN VII (The Facial nerve) is primarily a motor nerve, but does provide sensory fibers to which two anatomic locations?
Tongue and conchal bowl of ear
“Special” sensory fibers are carried to the anterior 2/3 of the tongue, supplying taste. Some sensory fibers are also carried within CN VII to the conchal bowl (the conchal bowl is also supplied by fibers from CN IX—the Glossopharyngeal nerve, and CN X—the Vagus nerve.
Mucosal and acral lentiginous melanomas have been associated with activating mutations in which gene?
KIT
The instrument shown is?
Halsted hemostat (mosquito clamp), note smaller tip than Kelly clamps
What mineral can be used to bind/chelate arsenic in exposed patients?
Selenium
A ring block around the ear will numb the entire ear except for which portions?
The conchal bowl and external auditory canal
Due to innervation by CNs VII, IX, and X
Isopropyl alcohol use in neonates has been reported to cause what rare complication?
Cutaneous hemorrhage and necrosis
What is the name of the specific test to determine the presence of V600E mutations in the BRAF gene?
The Cobas 4800 test
Patients with inflammatory bowel disease who are chronically treated with which drug show an increased risk of NMSC (especially SCC)?
Azathioprine
A similar increase in NMSC incidence is noted with use of 6-mercaptopurine
The instrument shown is?
Castroviejo needle holder (spring-loaded)
What nerve innervates this area of the foot?
Superficial peroneal (fibular) nerve
PTCH is a membrane receptor for what molecule?
Sonic hedgehog (SHH)
Botulinum toxins are contraindicated in patients with what 3 neurologic diseases?
- Amyotrophic lateral sclerosis (ALS)
- Lambert-Eaton syndrome
- Myasthenia gravis
Nephrotoxicity with use of mupirocin to large areas of body surface is due to absorption of what?
Polyethylene glycol
Same thing as the laxative MiraLax
Vismodegib’s mechanism of action is due to inhibition of what molecule?
Smoothened (Smo), a proto-oncogene
Smo activating mutations can lead to unregulated activation of the hedgehog pathway → BCC, pancreatic cancer, and prostate cancer
What is the name of the range within which protoporphyrin IX maximally absorbs UV light?
The Soret band (400-420nm)
Which commonly used superficial peeling agent is unique in that it requires neutralization?
Glycolic acid
Neutralize with saline or sodium bicarbonate
Ingenol mebutate is derived from what plant?
Euphorbia peplus (milkweed)
Ingenol mebutate is a treatment for actinic keratoses
What are the 3 classic symptoms noted in Trigeminal Trophic Syndrome?
Anesthesia, Paresthesia, and Erosion (APE), usually of the ala nasi
Classically due to injury to Gasserian ganglion
Which muscle supplied by CN VII is the only one known to classically be supplied on the superficial side of the muscle, as opposed to the deep?
Buccinator (a “forgotten” muscle of mastication → keeps food pressed against teeth)
What is the name given to the convergence of muscles of facial expression that occurs just lateral to the oral commissure?
Modiolus
What is the growth rate of the nail plate?
Fingernails → 3 mm per month
Toenails → 1 mm per month
Which topical antibacterial agent causes read-through of nonsense mutations and may therefore be particularly suited for use in superficial bacterial infections in patients with Hailey-Hailey disease?
Gentamicin
What can cause a pterygium after a nail matrix biopsy?
Allowing open nail matrix and proximal nail fold to fuse and form a scar
What subtype of BCC often presents as a pink, dome-shaped or pedunculated papule on the lumbosacral area?
Fibroepithelioma of Pinkus
Somatic mutations of which gene are noted in 40-85% of seborrheic keratosis?
FGFR3
“FuGgin-A! FRee me of these 3 SKs!” :P
Synaptobrevin is also known by what name?
Vesicle-associated membrane protein (VAMP)
Squamous cell carcinoma is the most common type of cutaneous malignancy in which two ethnic groups?
Asian-Indians and African Americans
The blade shown here is an example of what type (number) of blade?
15c
Notice notch immediately behind belly of blade → this is not seen with a regular #15 blade!
According to the most recent guidelines of the American Joint Committee on Cancer, what is the clinical size threshold that upstages a cutaneous SCC from Stage I to Stage II?
2 cm
What is the estimated percentage of patients with SCIS/Bowen’s disease that progress to develop invasive SCC?
3-5%
Effectively, less than 5%
True or false: facial veins lack valves.
True
The ability of suture to stretch and maintain its new length after deformation.
Plasticity
Elasticity is its ability to “snap” back to its initial length
Which specific branch of CN VII supplies the nerve fibers supplying taste to the anterior 2/3 of the tongue?
The chorda tympani branch
This is not to be confused with the somatic sensory fibers to the anterior two-thirds of the tongue, which are supplied by the lingual branch of V3
Which classes of medication can theoretically enhance the effect of neurotoxins? (3)
Aminoglycosides
Cyclosporine
Calcium channel blockers
Use of silver sulfadiazine in neonates has been associated with which two side effects?
Kernicterus and argyria
When the Sonic Hedgehog molecule is in the unbound state, the Patched receptor inhibits what intracellular signal?
Smoothened (Smo)
Which absorbable suture maintains its tensile strength the longest?
Polydioxanone (PDS)
What two subunits comprise the concha?
The superior cymba and the inferior cavum
Other than methemoglobinemia, what other complication has been seen in children (especially neonates) with EMLA use?
Purpura
Which antiseptic agent is a phenol?
Hexachlorophene
Neurotoxic, teratogenic, and highly absorbed → no longer used
What is the name of the duct which exits the parotid? And where does it enter the oral cavity?
Stenson’s duct exits the parotid gland and enters the oral cavity in the buccal mucosa adjacent the 2nd upper molar.
What is the overall one-year risk of actinic keratosis progression to primary SCC?
0.08%
Dermabond® should be used with caution in patients with a history of what contact allergy?
Acrylate allergy
Dermabond → 2-octyl cyanoacrylate
What is the most commonly used sterilization method in the office setting?
Steam autoclave
Which muscles are innervated by the temporal branch of cranial nerve VII? (3)
Frontalis, orbicularis oculi, corrugator supercilii (occasionally procerus as well, though this muscle is more traditionally innervated by the zygomatic branch)
Which topical antibacterial agent has the same mechanism of action as gentamycin (binds to 30S subunit of bacterial ribosome) but may also inhibit bacterial DNA polymerase?
Neomycin
The light-chain of the botulinum toxin A molecule is responsible for what portion of the neurotoxin’s mechanism of action?
Proteolytic cleavage of SNAP-25
The instrument shown in an example of what type of scissor?
O’Brien scissor (good for tight areas and for leveling beveled edges)
What site on the face receives the most cumulative UV exposure and is also the most common facial site for development of BCC?
The base of the nose (ala, lower nasal sidewall)
Which of the components of the commonly used triple-antibiotic ointment (neomycin/bacitracin/polymyxin B) is responsible for coverage of Pseudomonas?
Polymyxin B
The instrument shown in an example of what type of scissor?
Iris scissors
Which method of sterilization has the highest risk for corrosivity/dulling of sharp instruments?
Steam autoclave
Deep chemical peels traditionally cause injury to what level of the skin?
Mid-reticular dermis (0.6 mm)
Organ transplant patients are at how many times the increased risk for development of SCC than a non-transplanted patient?
65x increased risk of SCC
Of note, transplant patients are also at a 10x increased risk of BCC and a 3.4x increased risk of melanoma
What is the name of the perforating vessels that connect the great saphenous vein to the deep (femoral) veins of the leg at the level of the distal thigh?
Dodd perforators
What is the maximum recommended volume of anesthetic for a digital nerve block?
8 mL
Strive for < 4 mL total (e.g., 2 mL per side of finger)
Incobotulinumtoxin A is more commonly known by what name?
Xeomin®
The ability of suture to resist breakage or deformation?
Tensile strength
Which portion of the chemical structure of anesthetic molecules determines the duration of action?
Amine
Determines overall how lipid soluble the anesthetic agent is → more lipid soluble means longer duration of action
Where (between which two arteries) is the anastomosis between the ECA and ICA on the face?
Between the angular artery (from the ECA) and the dorsal nasal branch of the ophthalmic artery (off the ICA)
What is the preservative added to saline which, when used as the solvent for reconstitution, can decrease the pain associated with botulinum toxin injections?
Benzyl alcohol
Alcohol exerts its antimicrobial effects by what mechanism of action?
Microbial protein denaturation
Topical imiquimod has been rarely reported to cause what pigment abnormality?
Vitiligo-like eruption
Which sterilization method is most appropriate for heat-sensitive and moisture sensitive instruments?
Gas sterilization
Name the distinct subtype of seborrheic keratosis which is composed of small keratinocytes and dendritic melanocytes on microscopic examination.
Melanoacanthoma (do not confuse with oral melanoacanthoma, a rapidly growing reactive proliferation often seen in young African American Females).
What nerve innervates this area of the foot?
Sural nerve
Which topical antimicrobial agent, when used over a large amount of body surface area, has been shown to cause leukopenia?
Silver sulfadiazine
- Ulnar nerve block at the dorsal wrist involves injection just lateral (or radial) to which tendon?
- Between what two tendons should you inject for a median nerve block?
Flexor carpi ulnaris
Make sure to aspirate before injecting as the nerve lies close to the ulnar artery!
Inject between palmaris longus and flexor carpi ulnaris
For median nerve block, you inject between palmaris longus and flexor carpi radialis
The instrument shown is?
Webster needle driver (good for smaller needles, notice the shorter handle and smaller jaws than Crile-Wood → see photo)
