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USMLE
MSK Derm 3
Question | Answer |
---|---|
Cause of Green Nail Syndrome | P.aeurginosa usually acquired by prolonged exposure to water |
Superficial papules and pustules with erythematous halo on parts of body that are covered by shorts | Hot Tub Folliculitis |
Erythematous macule infarction bullae ulcer; a/w fever, chills, and tenderness in hospitalized/ immunocompromised patients | Ecthyma Gangrenosum |
Painless ulcer/chancre @ site of inoculation; Hard, clean edge with a yellowish base | Primary Syphilis |
Firm macules and papules that are pink, brownish-red; Scaly macules on palm; condyloma lata | Secondary Syphilis |
Plaques and nodules with scars healed in center with/without scales and with/without ulceration | Tertiary Syphilis |
Jarish-Herxheimer Syndrome | Flu-like symptoms within first 24 hours of treatment of syphillis; Normal process caused by lysing of spirochetes |
Condyloma acuminatum | Verrucae (warts) in genital region |
Flat to convex papules with rough, pebble-like surface | Verrucae (warts) |
Cause of Molluscum Contagiosum | poxvirus |
Firm, umbilicated (dent in the center), dome- shaped papules, shiny; Pruritic | Molluscum Contagiosum |
How is latency formed w/ Herpes simplex virus | Virus ascends in peripheral sensory nerves and enters dorsal root ganglia where latency is established |
Groups of small vesicles and shallow ulcers on erythematous base (pustules erosions crust) | Typical herpes lesions |
Patches of erythema, small erosions, fissures, or subclinical lesions | Atypical herpes lesions |
"Dewdrops on a rose petal" | Herpes Zoster |
Erythematous/Edematous base with superimposed clear vesicles w/ unilateral dermatome distribution | Herpes Zoster |
Most common dermatophyte infection | Trichophyton rubrum |
MCC of Tinea Capitas | Trichophyton tonsurans |
Athlete's foot | Tinea Pedis |
Dermatophyte infection on scalp | Tinea Capitas |
Dermatophyte infection on face | Tinea Facialis |
Dermatophyte infection in inguinal region | Tinea Cruris |
Dermatophyte infection on trunk/extremities | Tinea Corporis |
Dermatophyte infection on hand | Tinea Manuum |
Dermatophyte infection from pets | Microsporum canis |
sharply demarcated, polycyclic, erythematous, eroded patches with small pustular lesions; base can be scraped away w/ gauze | Candidiasis |
Cause of Pityriasis (tinea) versicolor | Malassezia furfur |
Well-demarcated scaling patches with variable pigmentation; Macules that are sharply marginated, round/oval in shape, with varying size | Pityriasis (tinea) versicolor |
"Spaghetti and meatballs" appearance on KOH stain | Pityriasis (tinea) versicolor |
Cause of scabies | Sarcoptes scabiei mite |
Gray/skin-colored ridges from 5mm to 10cm in length | Scabies |
Cause of Pediculosis | The arthropod Phthirus |
Hair lice | Pediculosis caused by Phthirus Humanus capitas |
Genital crabs | Pediculosis caused by Phthirus pubis |
Tx of Acne vulgarus | Tretinoin/Adapalene(retenoids) & Tetracyclines |
Tx for Gadolinium induced systemic sclerosis | Phototherapy |
Topical agent used to treat S. aureus and most Strep except group D | Mupirocin |
Topical agent used to treat dermatophyte infections | Griseofulvin |
Topical/oral agent used to treat dermatophyte infections | Terbinafine (an allylamine) |
Topical agent that is very effective on yeasts | Nystatin |
Tx of ectoparasites | Permethrin (preferred tx) & Lindane (not used as much due to neurotoxicity) |
Tx of psoriasis | Methotrexate(antimetabolite) & Cyclosporin (Calcineurin inhibitor) |
Topical Tx of actinic keratosis, Bowens disease and superficial basal cell carcinoma | 5-fluorouracil |
Tx of atopic dermatitis | Tacrolimus & Pimecrolimus(mild to moderate cases) Both are calcineurin inhibitors |
Patients on Calcineurin inhibitors must do what? | Wear sunscreen when outside due to cutaneous immunosuppresion that could lead to skin cancer |
Biological agent that binds 2 molecules of TNF | Etanercept |
Biological agent that binds to the TNF receptor | Infliximab |
MCC of dwarfism | Achondroplasia |
Cause of Achondroplasia | defect in a fibroblast growth factor receptor protein (FGFR3) Found on chrom 4 |
MCC of osteomyelitis | S. aureus |
MCC of osteomyelitis a/w GU infections | E. Coli, Pseudomonas, Klebsiella |
MCC of osteomyelitis a/w drug abuse | E. Coli, Pseudomonas, Klebsiella |
MCC of osteomyelitis in neonates | H. Influenzae and Group B Strep |
MCC of osteomyelitis in pt's w/ sickle cell disease | Salmonella |
Pott's disease | Tuberculosis osteomyelitis involving the spine |
Muscle disease w/ LMN signs | Poliomyelitis |
Muscle disease w/ both UMN & LMN signs | Amyotrophic lateral Sclerosis |
Muscle disease seen in infants ("floppy baby") | Werdnig-Hoffmann disease |
Symmetric ascending muscle weakness beginning in distal and lower extremities | Guillain-Barre Disease |
Genetics of Duchenne Muscular Dystrophy | X-linked recessive Complete absence of dystrophin gene |
Genetics of Becker’s Muscular Dystrophy | X-linked recessive Mutation causing production of truncated dystrophin |
Defect in Oculopharyngeal dystrophy | PABPN1(Poly-A binding protein, nuclear 1) gene on chrom 14 GCG trinucleotide expansion |
Defect in limb-girdle dystrophy | Mutation of laminin |
Defect in Emery-dreifuss dystrophy | Mutation of emerin(X-linked) Less commonly, mutation of laminin |
Defect in myotonic dystrophy | DMPK (dystrophila myotonia-protein kinase) gene on chrom 19 CTG trinucleotide expansion |
Defect in Nemaline myopathy | ACTA 1 gene on chrom 1; threadlike; dark inclusions of Z-band material in type I fibers |
Defect in Central Core Disease | RYR 1 gene on chrom 19; codes for a calcium release channel; a/w malignant hyperthermia |
Kearns-Sayre Syndrome | Ophthalmoplegia plus retinal pigmentary degeneration and complete heart block Caused by large deletion of mitochondrial DNA |
Dermatomyositis | Heliotrope rash with periorbital edema; Muscle weakness; myocarditis; interstitial lung dx, 40% have cancer too |