Ortho + Path (skin & bone) Flashcards
Lichenoid reaction (skin)
inflammation along dermal-epidermal junction.
- -> vacuolar change & cell death.
(4) : Lichen planus, Erythema Multiforme, Lupus, Graft vs. Host
3 factors that affect peak bone mass
- genetics
- physical activity
- nutrition
Lichen Planus (skin) pathology
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)
Erythema Multiforme pathology
Gross: target lesions = minor, skin sloughing = severe.
Histo: necrotic keratinocytes, spongiosis, dermal edema, lymphocytic infiltration, (normal basket-weave corneum)
Graft vs. Host skin pathology
Gross: erythematous, BLANCHABLE macules (severe = bullae), ~4 wks after transplant.
Histo: necrotic keratinocytes & liquefactive necrosis at basal layer.
Lupus skin pathology
Gross: “butterfly rash” on face, w/ spared labial folds.
Histo: follicular plug, liquefactive necrosis w/ lymphocytes @ DEJ (“bubbly, vacuolar basal cells)
Psoriasiform skin reaction
epidermal hyperplasia w/ regular, elongated Rete Ridges;
3): Psoriasis, lichen simplex chronicus, pellagra (*collar rash!
Psoriasis pathology
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.
Lichen Simplex Chronicus (skin) Pathology
= from chronic/excessive rubbing & scratching
Gross: leathery appearance (esp. hands, elbows)
Histo: Jagged Rete Ridges & vertical streaked collagen
Spongiotic skin reaction pattern
= intraepidermal intracellular edema,
*chronic => Lichenification
(4): eczema (atopic dermatitis), contact (irritant or allergic) dermatitis, sebhorreic dermatitis
Path: edema fluid btwn keratinocytes –> accentuate desmosomes.
“epidermotropism”
refers to directed emigration of lymphocytes into lower epidermis;
= malignant process.
*ie: mycosis fungoides!
Vesiculobullous (skin) reaction pattern
= vesicles or bullae (blistering) anywhere in epidermis;
(6): herpes, dermatitis herpetiformis, Scalded skin syndrome, impetigo, bullous pemphigoid, pemphigus vulgaris.
Scalded Skin Syndrome
(from staphylococcal exotoxin)
*vesicular fluid = sterile!
Histo: sloughed stratum corneum, rest of epidermis = intact.
Impetigo
Gross: honey-colored crust/eschar, (from staph aureus)
* CAN culture bacteria directly from bullous fluid
Histo: Crust & bacteria @ corneum, w/ perivascular lymphocytes.
bullous pemphigoid
autoimmune disorder esp. in elderly,
Gross: tense, pruritic blisters
Histo: subepidermal blisters w/ intact acanthocytes.
Pemphigus vulgaris
= 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.
dermatitis herpetiformis
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)
Leukocytoclastic vasculitis
= non-blanching erythema –> purpura;
Histo: vascular & fibrinoid necrosis (of vessel wall), + extravasated RBCs
Acanthosis nigrans pathology
= thick, hyperpigmented skin.
80% benign (childhood/puberty/youth onset DM2)
20% malignant (occult adenocarcinoma).
Histo: Basal cell layer hyperpigmentation, + hyperkeratosis
Verruca vulgaris pathology (skin)
Rete ridges slope inward!
also: supraepidermal hemorrhage, hyperkeratosis & hypergranulosis…
Dysplastic nevus pathology
- more likely to become malignant (skin neoplasm).
- melanocyte bridging btwn Rete Ridges
- melanocyte nesting = poorly organized
Spitz nevus pathology
LESS concerning skin neoplasm,
- well-circumscribed
- no (abnormal) mitotic activity
junctional vs. compound vs. intradermal nevus pathology
= hyperpigmented macules; = nest of melanocytes…
Junctional: @ DEJ only
Compound: @ DEJ & within dermis
Intradermal: within dermis only
Lentigo pathology
= skin neoplasm,
increased pigment WITHIN keratinocytes @ DEJ
Dermatofibroma pathology
Gross: benign, hyperpigmented plaque. + pinch test
Histo: Tabled Rete ridges & whorling spindle cells
dermatofibrosarcoma protruberans pathology
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.
Mycoides fungoides/Cutaneous T cell Lymphoma pathology
Gross: scaly brown plaques/patches w/ diffuse erythema;
Histo: cerebric, lymphocytic epidermotrophism (“Pautrier microabscess”) + perakeratosis.
*“Sezary Syndrome” = in blood
Merkel Cell carcinoma pathology
(neural crest derived)
Gross: dark, round, nodular
Histo: small, round, blue cells infiltrating dermis
Basal Cell Carcinoma pathology
Nodular: clustered basal cell proliferation, w/ peripheral palisading edges
Sclerosing: basaloid strands & fibrosis
Actinic keratosis pathology
Gross: premalignant plaque –> freeze off
Histo: parakeratosis & atypical keratosis w/ lymphocytic infiltration
Keratoacanthoma pathology
Gross: rapid growing, skin colored nodule w/ keratotic plug
Histo: localized, well-differentiated carcinoma (similar to SCC)
Melanoma pathology (general)
Histo: pagetoid melanocytes, atypical melanocytes, hemorrhage
layers of cartilage & their function
- Tangential - resist shear forces, high amt collagen type IX & H2O
- Transitional - resist compression
- Radial - distribute load, vertical organization
- calcified - hyaline cartilage, next to bone; CAN scar/heal in this layer only.
5 things to check for in emergency setting
ABCDE: Airway Breathing Circulation Disability/deformity Environment/exposure (ie: infection)
Signs of acute compartment syndrome
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)
True orthopedic emergencies
Fatal if no intervention within minutes - hours
- Vascular injury
- Acute compartment syndrome
- Intra capsular hip fracture (–> hemodynamic instability)
- Spinal cord injury
- Rapidly expanding infection (ie: necrotizing fasciitis)
Consequences of missed acute compartment syndrome
- Ischemic contractures
- Renal failure
- Amputation
- Death
Intramembranous bone formation
Direct bone formation of flat bones from mesenchymal condensation.
(Only early in dvpt)
–> skull, spine & pelvis
Endochondral bone formation
Formation of long bones by deposition of osteoid into cartilage framework.
- occurs at growth plates
- -> bones of limbs
Parts of bone
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
Components of bone extracellular matrix (4)
- Mineral matrix (esp. hydroxyapetite/Ca)
- Organic matrix (type I collagen)
- Water
- Cells (ostoblasts, osteoclasts, osteocytes)
Types of bone cells
Osteoblasts: make bone, = mesenchymal
Osteoclasts: break down bone, = multi-nucleated giant cells
Osteocytes: regulate mineral homeostasis
Primary bone healing
With surgery & hard cast,
=> rigid immobilization and precise approximation,
Osteoblasts deposit bones on cones along fracture
Secondary bone healing
Self-healing fracture, => cartilage laid to form scar, then osteoblasts remodel into bone. Stages: 1. Hematoma/inflammation 2. Callus (scar) 3. Remodeling (self-healing)
Normal blood flow direction in bone vs abnormal (with fracture)
Normal BF: outward from center of bone to edges
W/ fracture: BF toward center of bone (bc change in P)
Positive Galeazzi sign
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)
Barlow maneuver
Tests for developmental hip dysplasia in infant,
Adduct hips w/ light force on knees posteriorly.
+: feel hip dislocate when adducted
Ortolani maneuver
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)
Risk factors for developmental dysplasia of the hip
- Breech position for birth
- Female > male
- First born child
- Family history of DDH
* most commonly on left side
Major Infectious causes of joint pain in children
- 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)*
Main findings in osteoarthritis (4)
- Joint space narrowing
- Osteophytes/bone spurs
- Sclerosis
- Cyst formation
Greatest predictor of fracture
1: Previous fracture.
*also age: compression fractures VERY common in elderly.
