Ortho + Path (skin & bone)

Question 0

Lichenoid reaction (skin)

Answer 0

inflammation along dermal-epidermal junction.

• -> vacuolar change & cell death.
  (4) : Lichen planus, Erythema Multiforme, Lupus, Graft vs. Host

Question 1

3 factors that affect peak bone mass

Answer 1

1. genetics
2. physical activity
3. nutrition

Question 2

Lichen Planus (skin) pathology

Answer 2

Gross: - Koebner phenomena - “P’s” = pruritic, plateaued papules
- Wickham stria (reticular, lacy patterns on mucosal surface),
Histo: compact hyperkeratosis, hypergranulosis, & liquefactive degeneration (w/ colloid bodies)

Question 3

Erythema Multiforme pathology

Answer 3

Gross: target lesions = minor, skin sloughing = severe.
Histo: necrotic keratinocytes, spongiosis, dermal edema, lymphocytic infiltration, (normal basket-weave corneum)

Question 4

Graft vs. Host skin pathology

Answer 4

Gross: erythematous, BLANCHABLE macules (severe = bullae), ~4 wks after transplant.
Histo: necrotic keratinocytes & liquefactive necrosis at basal layer.

Question 5

Lupus skin pathology

Answer 5

Gross: “butterfly rash” on face, w/ spared labial folds.
Histo: follicular plug, liquefactive necrosis w/ lymphocytes @ DEJ (“bubbly, vacuolar basal cells)

Question 6

Psoriasiform skin reaction

Answer 6

epidermal hyperplasia w/ regular, elongated Rete Ridges;

3): Psoriasis, lichen simplex chronicus, pellagra (*collar rash!

Question 7

Psoriasis pathology

Answer 7

Gross: salmon colored plaque w/ silvery scale, Koebner phenom., & Auspitz sign (appears in areas of minor trauma)

Histo: Dilated papillary dermal vessels (Auspitz) & confluent parakeratosis.

Question 8

Lichen Simplex Chronicus (skin) Pathology

Answer 8

= from chronic/excessive rubbing & scratching
Gross: leathery appearance (esp. hands, elbows)
Histo: Jagged Rete Ridges & vertical streaked collagen

Question 9

Spongiotic skin reaction pattern

Answer 9

= intraepidermal intracellular edema,
*chronic => Lichenification
(4): eczema (atopic dermatitis), contact (irritant or allergic) dermatitis, sebhorreic dermatitis
Path: edema fluid btwn keratinocytes –> accentuate desmosomes.

Question 10

“epidermotropism”

Answer 10

refers to directed emigration of lymphocytes into lower epidermis;
= malignant process.
*ie: mycosis fungoides!

Question 11

Vesiculobullous (skin) reaction pattern

Answer 11

= vesicles or bullae (blistering) anywhere in epidermis;

(6): herpes, dermatitis herpetiformis, Scalded skin syndrome, impetigo, bullous pemphigoid, pemphigus vulgaris.

Question 12

Scalded Skin Syndrome

Answer 12

(from staphylococcal exotoxin)
*vesicular fluid = sterile!
Histo: sloughed stratum corneum, rest of epidermis = intact.

Question 13

Impetigo

Answer 13

Gross: honey-colored crust/eschar, (from staph aureus)
* CAN culture bacteria directly from bullous fluid
Histo: Crust & bacteria @ corneum, w/ perivascular lymphocytes.

Question 14

bullous pemphigoid

Answer 14

autoimmune disorder esp. in elderly,
Gross: tense, pruritic blisters
Histo: subepidermal blisters w/ intact acanthocytes.

Question 15

Pemphigus vulgaris

Answer 15

= autoimmune destruction of desmoglein III, @ mucus membranes!
Gross: Nikolsky’s sign (loose blister, shifts w/ pressure)
Histo: intraepidermal splitting, suprabasilar vesicle; w/ Acantholysis & “tombstone” row.

Question 16

dermatitis herpetiformis

Answer 16

cutaneous blistering associated w/ gluten sensitivity (IgE!);
Gross: symmetrical eruptions (esp. hands, forearms)
Histo: subepidermal blister, many Eosinophils & neutrophils!!!
(also: IgA deposited @ tips of dermal papillae)

Question 17

Leukocytoclastic vasculitis

Answer 17

= non-blanching erythema –> purpura;

Histo: vascular & fibrinoid necrosis (of vessel wall), + extravasated RBCs

Question 18

Acanthosis nigrans pathology

Answer 18

= thick, hyperpigmented skin.
80% benign (childhood/puberty/youth onset DM2)
20% malignant (occult adenocarcinoma).
Histo: Basal cell layer hyperpigmentation, + hyperkeratosis

Question 19

Verruca vulgaris pathology (skin)

Answer 19

Rete ridges slope inward!

also: supraepidermal hemorrhage, hyperkeratosis & hypergranulosis…

Question 22

Dysplastic nevus pathology

Answer 22

• more likely to become malignant (skin neoplasm).
• melanocyte bridging btwn Rete Ridges
• melanocyte nesting = poorly organized

Question 23

Spitz nevus pathology

Answer 23

LESS concerning skin neoplasm,

• well-circumscribed
• no (abnormal) mitotic activity

Question 24

junctional vs. compound vs. intradermal nevus pathology

Answer 24

= hyperpigmented macules; = nest of melanocytes…
Junctional: @ DEJ only
Compound: @ DEJ & within dermis
Intradermal: within dermis only

Question 25

Lentigo pathology

Answer 25

= skin neoplasm,

increased pigment WITHIN keratinocytes @ DEJ

Question 26

Dermatofibroma pathology

Answer 26

Gross: benign, hyperpigmented plaque. + pinch test Histo: Tabled Rete ridges & whorling spindle cells

Question 27

dermatofibrosarcoma protruberans pathology

Answer 27

well-differentiated primary fibrosarcoma, @trauma/scar site; locally aggressive, does NOT spread to lymph nodes, recurs. Histo: storiform pattern (whorling spindle cells), spindle cells infiltrate adipose tissue.

Question 28

Mycoides fungoides/Cutaneous T cell Lymphoma pathology

Answer 28

Gross: scaly brown plaques/patches w/ diffuse erythema; Histo: cerebric, lymphocytic epidermotrophism ("Pautrier microabscess") + perakeratosis. *"Sezary Syndrome" = in blood

Question 29

Merkel Cell carcinoma pathology

Answer 29

(neural crest derived) Gross: dark, round, nodular Histo: small, round, blue cells infiltrating dermis

Question 30

Basal Cell Carcinoma pathology

Answer 30

Nodular: clustered basal cell proliferation, w/ peripheral palisading edges Sclerosing: basaloid strands & fibrosis

Question 31

Actinic keratosis pathology

Answer 31

Gross: premalignant plaque --> freeze off Histo: parakeratosis & atypical keratosis w/ lymphocytic infiltration

Question 32

Keratoacanthoma pathology

Answer 32

Gross: rapid growing, skin colored nodule w/ keratotic plug Histo: localized, well-differentiated carcinoma (similar to SCC)

Question 33

Melanoma pathology (general)

Answer 33

Histo: pagetoid melanocytes, atypical melanocytes, hemorrhage

Question 34

layers of cartilage & their function

Answer 34

1. Tangential - resist shear forces, high amt collagen type IX & H2O 2. Transitional - resist compression 3. Radial - distribute load, vertical organization 4. calcified - hyaline cartilage, next to bone; CAN scar/heal in this layer only.

Question 35

5 things to check for in emergency setting

Answer 35

``` ABCDE: Airway Breathing Circulation Disability/deformity Environment/exposure (ie: infection) ```

Question 36

Signs of acute compartment syndrome

Answer 36

Pain out of proportion to injury & w/ passive stretch, tense mm compartment, paresthesia, paralysis and progression. Treat with fasciotomy. (Do NOT Tx w/ fasciotomy IF late (>8hrs) --> irreversible injury, limb = nonfunctional or avascular, or if coagulopathy)

Question 37

True orthopedic emergencies | Fatal if no intervention within minutes - hours

Answer 37

1. Vascular injury 2. Acute compartment syndrome 3. Intra capsular hip fracture (--> hemodynamic instability) 4. Spinal cord injury 5. Rapidly expanding infection (ie: necrotizing fasciitis)

Question 38

Consequences of missed acute compartment syndrome

Answer 38

1. Ischemic contractures 2. Renal failure 3. Amputation 4. Death

Question 39

Intramembranous bone formation

Answer 39

Direct bone formation of flat bones from mesenchymal condensation. (Only early in dvpt) --> skull, spine & pelvis

Question 40

Endochondral bone formation

Answer 40

Formation of long bones by deposition of osteoid into cartilage framework. * occurs at growth plates - -> bones of limbs

Question 41

Parts of bone

Answer 41

Diaphysis: shaft of bone, = thick, cortical (= lamellar) Metaphysis: small area of trabecular bone btwn diaphysis & epiphysis Epiphysis: articular surface (end), separated from metaphysis by growth plate

Question 42

Components of bone extracellular matrix (4)

Answer 42

1. Mineral matrix (esp. hydroxyapetite/Ca) 2. Organic matrix (type I collagen) 3. Water 4. Cells (ostoblasts, osteoclasts, osteocytes)

Question 43

Types of bone cells

Answer 43

Osteoblasts: make bone, = mesenchymal Osteoclasts: break down bone, = multi-nucleated giant cells Osteocytes: regulate mineral homeostasis

Question 44

Primary bone healing

Answer 44

With surgery & hard cast, => rigid immobilization and precise approximation, Osteoblasts deposit bones on cones along fracture

Question 45

Secondary bone healing

Answer 45

``` Self-healing fracture, => cartilage laid to form scar, then osteoblasts remodel into bone. Stages: 1. Hematoma/inflammation 2. Callus (scar) 3. Remodeling (self-healing) ```

Question 46

Normal blood flow direction in bone vs abnormal (with fracture)

Answer 46

Normal BF: outward from center of bone to edges | W/ fracture: BF toward center of bone (bc change in P)

Question 47

Positive Galeazzi sign

Answer 47

In infants to Dx developmental dysplasia of the hip; w/ baby supine, flex knees so ankles touch butt. +: knees not even/level (May have increased, asymmetrical skin crease on leg)

Question 48

Barlow maneuver

Answer 48

Tests for developmental hip dysplasia in infant, Adduct hips w/ light force on knees posteriorly. +: feel hip dislocate when adducted

Question 49

Ortolani maneuver

Answer 49

Test for developmental dysplasia of the hip in infants, Used with Barlow maneuver, here abduct hips from tucked position (start with knees and hips flexed, legs together) +: feel hip relocate when abducted (bc dislocated w/adduction)

Question 50

Risk factors for developmental dysplasia of the hip

Answer 50

1. Breech position for birth 2. Female > male 3. First born child 4. Family history of DDH * most commonly on left side

Question 51

Major Infectious causes of joint pain in children

Answer 51

- Septic arthritis (bacterial infection of joint, *elevated CRP) - toxic synovitis (post-viral hip inflammation; afebrile, normal labs) - Lyme infection (joint swelling, test with Lyme titer) - osteomyelitis (bacterial infection of bone) * juvenile RA (autoimmune, not infectious)*

Question 52

Main findings in osteoarthritis (4)

Answer 52

1. Joint space narrowing 2. Osteophytes/bone spurs 3. Sclerosis 4. Cyst formation

Question 53

Greatest predictor of fracture

Answer 53

#1: Previous fracture. *also age: compression fractures VERY common in elderly.