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180 Cards in this Set

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What ar ethe compensatory mechanisms in anemia?
increased cardiac output: palpitaitons, dizziness, syncope
redistribution of blood: pallor
Right shift in Hb-O2 curve due to increased 2,3-BPG
What are the causes of micrcytic anemia?
iron deficiency, ACD, thalassemia, sideroblastic anemia, hemoglobin E
What anemia have a dificiency in heme synthesis?
iron deficiency, ACD, sideroblastic anemia
What anemias have a deficiency in globin synthesis?
thalassemia and HB E
What are the pts at risk for iron deficiency?
Infants (breast milk), women of reproductive age (menses), disease w/ chronic blood loss (GI CA)
What is the presentation of Fe deficiency?
Plummer Vinson syndrome: esophageal web, koilonychias, glossitis,

What are the 2 products released in ACD?
hepcidin: prevents lease of iron from macrophages
lactoferin: sequesters iron from bacteria
What pts get ACD?
chronic inflammatory disease: RA, TB
alcoholics, cancer
What makes up HbA2, HbF?
alpha w/ either delta, gamma
What is does beta thalassemia major looks like?
no HbA, increased HbF & HbA2
sever anemia, splenomegaly, expanded marrow (distorted bones)
requires frequent RBC transfusions
overtransfusion --> hemosiderosis
Which thalassemia has normal Hb electrophoresis?
alpha thalassemia trait
What thalassemia results in hydrops fetalis? What virus?
Hb Bart
Parvovirus B19
What 2 enzymes are damaged by Pb in anemia?
ferrochelatase: addes Fe to protoporphyrin
ribonuclease: degrades RNA of ribosomes --> basophilic stippling
What causes basophilic stippling in Pb poisoning?
Pb denatures ribonuclease whihc normally degrades RNa of ribosomes
What is the presentation of Pb poisoning?
GiL colic w/ diarrhea, Franconi's proximal RTA, loss of GAP in urine (glucose, amino acids, phosphate)
CNS: encephalopathy, PNS (wrist and foot drop)
sideroblastic anemia w/ basophilic stippling
How does Pyridoxine cause anemia? Presentation? Causes?
B6 is a cofeacter for delta-aminolevulinic acid synthase
seizures, irritability, cheilitis, anemia
diet, INH
What chemical is found in both folic acid and B12 deficiency? What chemical is only found in B12 and leads to demyelination?
methylmalonyl CoA
What are causes of B12 deficiency?
malnutrition, gastric bypass, pernicious anemi, chronic pancreatitits, ileal diseases, bacterial overgrowth or diphyllobothrium latum
What are causes of folate defiicency?
malnutrition, pregnancy, drug induced (5-Fu, methotrexate, trimethoprim-sulfa
What is the clinical precentation of megaloblastic anemia?
macrocytic anemia, jaundice secondary to RBC lysis, pancytopenia, HYPERSEGMENTED PMNS, prothrombotic effect form elevated homocysteine

Neurological effect (B12 only)- subacute combined degeneration of posterior columns and lateral STT --> decrease in vibratory and proprioception and umn lesions w/ hyperrreflexia
What are other cuase of megaloblastic anemia?
liver disease, myelodysplasia,
What are causes of reticulocytosis?
hemolysis, hemorrhage, hematinic

What are causes of normocytic anemia with low retic count?
aplastic anemia, chronic renal failure, acute blood loss, early ACD
What worsens HbS sickling?
low O2 tension: acidosis, volume depletion, hypoxemia
What is the presentation of sickle cell anemia?
hemolytic crisis
aplastic crisis, thrombosis, sequestration
How do you diagnose sickle cell?
sickle cell solubility screen, electrophoresis (HbAS), peripheral blood smear has target cells, sickled cells, Howell-Jolly bodies
What is the defect in hereditary spherocytosis? How do you diagnose?
autosomal dominant defect in ankyrin and spectrin
Blood smear (spherocytes-round w/o central pallor) and osmotic fragility test
What is the mutation in hereditary elliptoctosis?
spectrin or band 4.1
oval shaped
What is the pathogenesis of paroxysmal nocturnal hemoglobinuria? Presentation? dx?
Loss of anchoring protein for decay accelerating factor and CD59 --> susceptilibty to destruction by complement
episodic hemoglobinuria (night time acidosis -->complement binding due) risk for AML, increased thrombosis, especially hepatic vein (Budd-Chiari syndrome)

Dx: Sugar water test, Ham test
What is the pathogenesis, causes, and dx of G6PD deficiency?
X linked deficiency
cannot maintain glutathione which protects RBCs form oxidative damage
oxidized Hb precipitates as Heinz bodies and which are removed by splenic macrophages to form bite cells

Causes: infection, oxidizing drugs, malaria drugs
ingestion of fava beans

Heinz bodies, bite cells
PK deficiency pathogenesis? Dx?
Autosomal recessive defect in PK, normally converts PEP to pyruvate with gain of ATP
low ATP causes hemolytic anemia

Dx: Echinocytes, RBC enzymes
What are the alloimmune hemolytic anemias?
hemolytic transfusion reactions, hemolytic disease of the newborn
what are the 2 types of autoimmune hemolytic anemias?
Warm AIHA- IgG at body temp. Viral, SLE, CLL, drug, penicillin, alpha-methyldopa

Cld- IgM. infection, drug induced. Complement
What are the causes of microangiopathic hemolytic anemias? what is seen on blood smear?

schistocytes and helmet cells
What is a left shift?
increase i number of bands (immature PMNs)
What are reactive changes in PMNs associated w/ infection?
toxic granulation, vacuolization, Dohle bodies
What are the age groups form leukemia?
ALL 0-14, AML 15-60, CML 40- 60, CLL 60+
What is myelodysplasia? Peripheral blood/bone marrow presentation?
Ineffective hematopoeiesis and dyspoiesis of other cell lines.
Cells stuck in marrow --> thick marrow and thin blood

pancytopenia with macrocytic anemia non-responsive to B12/folate
circulating blasts or nucleated RBCs
abnormal blood cell morphology (dyspoiesis): erythrocytes: megaloblastic, oval, weird nuclei, ring sideroblasts
leukocytes: hypogranular, abnormal segmentation (Pelger-huet), basophilia, megakaryocytes w/ unusual lobulation and hypogranular platelets

Hypercellular bone marrow and less than 20% of marrow are blasts
What is ALL?
MC leukemia in 0-14, association w/ Down's syndrome
Sx of bone marrow suppression (pancytopenia), FUO, bone pain. Mets to various organs- MC CNS, mediastinum, testicles, renal, bone/joint.

Prognosis: Hyperdiploidy has better prognosis. Age 1-10 is better. t(12;21) is better. WBC > 100k has poorer prognosis. T-cell and Burkitt's have poorer prognosis.
What is AML?
adults>children 15-60
M2/M3 have Auer rods
Staining: myeloperoxidase and sudan black (M3), alpha naphthyl esterase (M4/5)

Bone marrpow suppression
What are the significant AMLs?
M3- promyelocytic: multiple Auer rods, DIC, translocation t(15;17), all-trans retinoic acid (vit A) tx

M5 (monocytic): gingival hyperplasia
What is CML?
hypercellular bone marrow and increased peripheral cells --> thick blood, thick marrow
Splenic enlargement as spleen tries to clear malignant cells
Progressive marrow fibrosis

transform into AML aka blast crisis
translocation t(9;22) w/ bcr-abl fusion gene on Philadelphia chromosome 22. Gleevec or Imatinib is a tyrosine kinase inhibitor used to treat.
Decreased LAP score
What is associated with Pelger-Huet segmentation?
What is CLL?
old patients,
dusfunctional B cells results in hypgammaglobulinemia
Smudge cells on peripheral blood smear.
CD5 B cells are present
What is hairy cell leukemia?
hair cells are cells with porjection of cytoplasms. Peripherla blood: pancytopenia. Splenomegaly.
Resistance to TRAP stain.
Polycythemia Vera?
proliferation of erythroid cell line --> increased Hb and Hct, increased plasma volume, decreased EPO

Presentation: hyperviscosity --> thrombotic events (Budd-Chiari) and HF
hyperuricemia --> gout (breakdown of cells --> purine release
Histamine release --> flushing, red/congested skin

Tx: phlebotomy

differential: hypoxic states have elevated EPO and decrease SaO2
Ectopic EPO has increased EPO
Polycythemia vera has decreased EPO
Myelofibrosis with myeloid metaplasia?
fibrotic bone marrow form inappropriate growth factors form neoplastic megakaryocytes

splenomegaly as cells move to spleen and cause extramedullary hematopoiesis

teardrops RBCs due to fibrosis of bone marrow
immarture RBCs and myeloid cell in periphery
variable platelet count
WBCs eleavted, but immature
Essential thrombocytopenia?
proliferaiton of megakaryocytes --> overproduction of useless platelets --> high count, but bleeding
What is the presentation of multiple myeloma?
hypercalcemia, renal failure, anemia (Rouleaux formation), bone lesion
painless LAD
fever, wt loss, night sweats
What characterizes Hodgkin's versus Non-Hodgkin's?
Hodgkin's: axial, contiguous, polyclonal lymphoid cells

Non-Hodgkin's: Peripheral, non-contigous, common mesenteric and extranodal sites
What are low-grade Non-Hodgkin's lymphomas?
Small lymphocytic lymphoma- oslid counterpart to CLL. CD5 on B cells

Follicular lymphoma- BCL-2 oncogene expression, t(14;18) translocation
What are high-grade B-cell lymphonmas?
Diffuse large B cells

Burkitt's lymphoma- starry sky macrophagges. C-myc onocogene w/ t(8;14) translocation
What are the T-cell lymphomas?
Mycosis fungoides- psoriatic rash unresponsive to steroids

Sezary syndrome- T cells enter blood and circulate- Buttock cells
Hodgkin's lympa?
Ree-Sternberg Cells
contigous spread, rearely extranodal

nodular sclerosing MC type with bands of fibrosis transecting the node with lacunar cells
Why do platelets release serotonin?
What are the reactions of platelets?
adhesion-interaction between specific platelet surface glycoprotein receptors and subendothelial collagen
activation of coagulation cascade- contributes platelet phospholipids- makes activation of thrombin possible
arachadonic acid metabolism- leads to formation of thromboxane A2- vasoconstrictor and platelet aggregant
platelet aggregation
stabilization of platelet plug- by fibrin
What makes factor XIII and factor VIII?
endothelial cells
What are the Vitamin K dependant factors?
II, VII, IX, X require gamma-carboxylation in the LIVER
protein C, S
What is the common pathway?
X--> Xa
Xa complexes with factor Va, Ca2+ and phospholipids
Xa-Va-Ca2+-PL complex (prothimbinase) converts prothrombin to thrombin
What is the extrinsic pathway?
Tissue factor (thromboplastin) is released upon tissue injury and activates factor VII.
TF-VII complex and active IX, X
Measured by PT which measures II, V, VII, X, and fibrinogen
What is the intrinsic pathjway?
High molecular weight kininogen and kallikrein activate factor XII
Factor XIIa activate factor XI which activate factor IX.
Factor IXa + factor VIIIa and vWF activate factor X
Measured by PTT
Measures everything except 7 and 13. 2, 5, 8-12, fibrinogen
What is the process of fibrinolysis?
tPA converts plasminogen to plasmin. Plasmin splits fibrin --> fibrin degradation productions (FDPs) and d-dimer

d-dimer eleated in PE, DVT, DIC
What are inhibitors of the coagulation factors?
Antithrombin III- Proteinase inhibitor- enhanced by heparin

Protein c cleaves factor Va into its inactive form, inactivates VIIIa and requires Protein S as cofactor and thrombomodulin on endothelium.

Tissue factor pathway inhbittor binds TF-VIIa-Xa comple to inactivate extrinisc pathway
What are Virchow's triad?
endothelial injury
What are Pts w/ antithrombin III deficiency resistant to?
What is Factoir V Leiden
Factor V mutation prevents activated protein C from binding and inactivating factor Va.
What is the 20210A transition in Prothrombin?
eleavted prothrombin levels and increase in venous thrombosis
What is MTHFR C677T mutation adn tx?
increased homocystein --> thrombosis

Tx: folic acid, B12, and B6 to counteract methionine loading
What are examples of antiphospholipid antidbodies? What do they do?
Lupus anticoagulant, anti-cardiolipin Abs

they prevent clotting cascade --> recurrent thromboembolism, fetal loss, thrombocytopenia
What nerves are used for nerve biopsy?
sural nerve (sensory), peroneal nerve (motor)
What are used for muscle biopsy?
vastus lateralis, deltoid, biceps brachii, tibialis anterior
What are the nerve layers from in to out?
endoneurium, perineurium, epineurium
What are the muscle fiber types?
Type I- slow twitch. Many mitochondira, lipid rich. Red appearance. Light on ATYPase pH 9.4 stain.

Type II "fast twitch" few mitochondria, glycogen rich. White appearance. Dark on ATPase 9.4 stain.
What is a motor unit?
1 lower motor neuron and the muscle fibers it innervates
What is segmental demyelination?
Dmage to Schwann cells w/o dmage to axon
Axon sends out message for differentiation of neraby regenerative cells into new Schwann cells
Schwann cells cells phagocytose dead myelin and undergo mitois
New myelin sheath is thinner and has increased Nodes of Ranvier --> slow conduction time

Onion bulbs

Teased nerve fibers w/ lipid stain --> thining due to lack of myelin
What are onion bulbs in the context of neuronal injury?
Seen w/ repeititive cycles of demyleination.remyleination
concentric layers of Schwann cell projections surrounding the axon
What is axonal degeneration? When is regeneration possible?
Primary destruction of the axon w/ secondary degeneraiton of the myelin sheath
nerve body is intact
What is Wallerian degeneration?
distal degeneration after axonal damage
swelling and vacuolization of nerve fibers
enlarged nerve cells, lots o dark cytoplasm w/ abundant lipid
What is a traumatic neuroma?
nodular mass of nerve fibers and Schwann cells
occurs when scarring obstructs new growth cone fro it endpoint
What is muscle denervation?
loss of LMN results in muscle fiber atrophy
Muscle can survive until reinnervationed, but willl be angulated and shrunken

may be reinnervated by a nearby neuron, can result in a switch of fiber type or grouping
What are 4 muscle pathological reactions?
fiber necrosis: segmental, macrophage infiltration and dead myofibrils on H&E
Fiber regeneraiton: can occur if endomysial tube remains intact [basophilic cytoplasm and regenerative nuclei]
internal nuclei: very non-specific change
Ringed fibers: fibers run perpendicular to normal orientation
What are the Sx of UMN and LMN lesions?
UMN- hyper-reflexia, spasticity, + Babinski
LMN- muscular atrophy, weakness, fasiculations
What is spinal muscular atrophy?
autosomal recessive disase with progressive loss of LMNs
SMN1- responsible for disease
SMN2- extra copy --> less severe disease

As Type's increase in number, severity decreases

Macroscopic: Anterior roots are grey and atrophic
Microscopic: nerve biopsy --> overall loss of neurons, w/ few swollen residual neurons
muscle biopsy --> atrophic cell sheets with some hypoertorphic cells
What is poliomyelitis?
polio virus invades the nervous system and damages motor neurons

Respiratory and GI Sx
LMN --> flaccid paralysis
respiratory failure
atrophic muscle replaced w/ fat

Post-Polio syndrome- progressive weakness associated w/ decreased muscle bulk and pain
What is the presentation of diabetic neuropathy?
symmetrical, decreased sensation andparesthesia in distal extremities
autonomic: gastroparesis, impotence, neurogenic bladder, orthostasis
thinkly myelinated fibers and vascular thickening
What characterizes sarcoidosis neuropathy?
granulomas in perineurium w/ atrophic nerve fibers
What characterizes amyloidosis neuropathy?
Sensory or sensorimotor neuropathy
pink, hyaline material in nerve cells
What is the pathology of ischemic neuropathy?
widespread axonal loss w/ fascicles on EM
What is Charcot-Marie-Tooth
mutations in neural proteins affecting the myelin sheath and axon. Autosomal dominant

presents in childhood w/ atrophy of lower leg muscles
peroneal nerve atrophy
legs have inverted bottle appearance
onion bulb changes
What is GBS?
autoimmune inflammation w/ demyleinatoin of peripheral motor fibers
ascending muscle weakness, starting with LE --> neurological deficits
T cells infilitration and attacking myelin sheaths
autoimmune response to infection or vaccines
What is myasthenia gravis?
autoantibodies against ACH receptors
ptosis, double vision, worsens w/ use muscle weakness.
thymic hyperplasia > thymoma
prolong survival w/ tx
What is Lambert-Eaton syndrome?
auto-antibody against pre-synaptic Ca channel
similar to M, proximal muscle weakness
praneoplastic syndrome associated with small cell CA
What helps with dx of polymyositis and dermatomyosistis?
anti-Jo-1 Abs, 50% ANA
lymphoid inflammation and atrophy/necrosis of muscle
What is inclusion boy myositis?
distal muscle weakness
rimmed vacuoles on trichome stain
EM of vacuoles just shows membraneous debris in cytoplasm
What are mitochondrial myopathies?
mutaitons in mitochondrial DNA or DNA coding leads to deficient ATP production
presents in young adulthood with proximal and ocular muscle weakness
neurological Sx, lactic acidosis, cardiomyopathy

ragged red fibers characteristic on trichome (aggregates of abnormal mitochondria)
parking lot inclusion on EM (abnormally stacked cristae)
What is nemaline rod myopathy?
non-progressive, proximal muscle weakness
nemaline rods within fibers on trichome staine
Z-band like material in clumps on EM
What causes toxic necrotizing myopathies? Vacuolar myopathy?
alcohol, stains, snake venoms

colchicine, chloroquine
Wha tis the inheritance of Becker's muscular dystrophy?
X-linked recessive
What is myotonic dystrophy?
CTG repeat tha taffects the mRNA for a muscle protein kinase

grip and percussion myotinia
distal muscle and facial weakness (ptosis)
frontal cataracts, balding

internal nuceli, variation in fiber size, ringed fibers
thickening of stratum corneum --> scaly appearance (psoriasis)
persistence of nuclei in cornified layer (normal on mucous membranes)
thickening of basal and spinosum layers (psoriasis)
intercellular edema in the epidermis (eczema)
inflammatory cels entering the epidermis
loss of connections between keratinocytes
premature keratin in lower layers
Seborrheic keratosis
round/elevated/pigments, raisin-like, stuck on
may resemble melanomas
hyperkeratosis and acanthosis w/ pseudohorn cysts (islands of keratin within epidermis)
What is Leser Trelat sign?
multiple seborrheic keratoses in a short time due to paraneoplastic syndrome of GI CA
What is a fibrous dermal core surrounded by normal epidermis?
What is an epidermal cyst (sebaceous cyst)?
pea-like nodul under the skin surface
cyst wall w/ keratin debris, surrounded by normal epidermis
spontaneous inflammation, rupture
What is a dermatofibroma?
firm, tan/brown papules on leg (dermal tumro = under epidermis)
Histology: spindel cell proliferation w/ hyperpasia of overlying layer
What is a freckle? What are liver spots? what causes them?
Sun/increase in melanocytes
What are actinic keratosis (Bowen's disease)?
red/raised plaque w/ scale in sun exposed regions; scale returns if scraped
dysplasia of keratinocytes
Pre-malignant- basal or squamous cell
What are keratoacanthoma?
resemble squamous cell carcinoma
volcano-like crater filled w/ keratin
may progress in to SCC
regresses due to immune reaction
What are nevocellular nevus?
proliferation of nevus cells (modified melanocytes)
juncitonal, compound, inttradermal
clustersof typical looking melanocytes
What is a dysplastic nevus?
pre-malignant version of nevocellular nevus, irregularly pigmented/bordered
Histo: atypia of melanocytes, dermal fibrosis, inflammation, melanocytes migrating to surface
Risk of melanoma
dysplatic nevus syndrom- hundred of nevi
Solar elastosis?
actinic damage
severely wrinkled skin secondary to chronic sun exposure
UV light activates proteases
degernation of dermal collagen
Basal cell carcinoma
papule, pearly borders; teleanectasia
sun exposed areas above the mouth
MC skin cancer in US
blue staining cells, bud off the basal alyer
does not metastasize --> local excision is curative
Squamous Cell Carcinoma
nolduar/scaly lesion, may be ulcerated/crusted
sun exposed areas below the mouth
MC skin cancer associate w/ immunosuppression
pink stainig atypical squamous cells w/ keratin perals
low risk of metastasis if neglected
Malignant melanoma
melanocyte cancer, lower legs & back
majority de novo, some pre-existing nevi
MC fatal skin cancer
Risk: ligh complexion, freckles, sun exposure, peeling sunburns, dysplastic nevus syndrome or increased number of nevi, Xeroderma pigmentosum

Radial and vertical growth phases

Superficial spreading: radial growth
Lentigo malgina: occurs on face, least metatastic
Nodular: aggressive, starts in vertical phase
Acral lentiginous: palms, soles, under nails; dark skinned

Prognosis: depth of invasion
Verruca vulgaris
Moluscan contagiosum
firm papules w/ central umbilication (dimpling)
molluscum bodies- viral inclusion within epidermal cells
staph aureus- persistent bullae
honey-colored crust of dried pus - Group A Strep
painful yellow pustules within surrounding erythema around hair follicleStaph/Strep or pseudomonas

topical corticosteroid use- staph/strep
hot tub- pseudomonas
infection of top half of dermis; edematous/warm/erythematous
associated fevers, rigors, vomitting, fatigue
deeper infection of skin spreading through dermis or subQ
lymphatic streaks signifies a severe case of spread
may resulting in necrotizing fasciitis
caused by staph/strep or H. flu
What are the stages of eczema?
acute eczema- weeping papules, vesicles, bullae
histo: spongiotic edema secondary to congestion, vascular dilation

subacture eczema- red/scale/crusting lesion form reactive hyperplasia
Histology: hyperkeratosis

chronic eczema- dry, red/scaly, fissuring
Histo: hyperkeratoris and acanthosis, relongation of rete ridges
What are the subtypes of eczema?
atopic eczema- flexural areas, children, asthma

Seborrheic dermatitis (cradle cap)- yellow sclaes on infant scalp

discoid eczema- discrete erythematous coin-shaped lesions

lichen simplex- respnse to chronic rubbing/scratching

Contact dermatitis- irritant vs allergic
symmetrical salmon-pink patchesw/ silvery scale on extensor surfaces
due to increased epithelial turnover, leading to epidermal hyperplasia
associated w/ rheumatoid-like psoriatic arhtritis
PMN infiltrate, hyperkeratosis/acanthosis, dilated dermal papillae
pityriasis rosea
herald patch- initial oval-shaped scaly plaque on trunk --> followed by pink patches w/ ring of scale (target) spreading in a Christmas tree distribution
Lichen planus
pataches of purple, pruritic, polygonal papules; slow epithelial turnover
Koebner phenomenon, also seen in psoriasis
lymphocyte infilitrate at basal layer, Civate bodies (destroyed basal cells), sawtooth appearance at dermis-epidermis junction
Acne vulgaris
androgen- driven overactivity of sebaceous glands w/ ductal obstruction
bacteria convert sebum to inflammatory fatty acids

comedones, papule, pustule, cysts, scars
papules/pustules w/ flushing and erythema of cheeks, forehead, nose, chin
Histology: vascular dilation (leads to flushing) and sebaceous hyperplasia
Bullous pemphigoid
abs to basement membrane at dermal-epidermal junction (hemidesmosomes)
epidermis separating from dermis in an intact later
tense, itchy bullae vesicle that don't pop easily due to intact laters
biopsy w/ immunofluorescence, Ab-Ag complex at junction
Abs to intraepidermal junction (desmisomes)
results in epidermal cellsseparating from each other, thus skin easy to break
Easily broken bliders, painful erosing, espec mucous membranes
immunofluorescence shows IgG, C3 between epidermal cells
Toxic erythema
ithcy, red maculopapular
Erythema multiforme
symmetrical target lesion, may have blisters
lymphoid dermail inflammation
infeciton, drugs, SLE, vasculitis
Stevens-Johnson is related wot which erythema?
erythema multiforme majorum
What cause urticaria?
type 1 hypersensitivity
transient red swelling w/ central pallor
What are diaphysis- metaphysis, and epiphysis?
long shaft, middle area, rounded edges
What are 2 gross bone types?
cortical and trabecular
What are the molecular bone types?
lamellar, woven bone
What are the fractures types?
simple vs complex
complete vs incomplete
comminuted fracture
pathologica fracture
stress fracture
What are the steps of fracture healing?
osteoblasts/osteoclasts at ends of fracture die due to ischemia
collagen is laid down
vascularity increases
osteoprogenitor cells stimulated --> callus formation
endochondrial bone formation may occur
woven bone remodeled to stronger lamellar bone
Factors that poorly affect healing
poor alignment
failure to immobilize --> delay healing, pseudoarthrosis- fibrosis rather than bony bridge
infection, low blood supply, nutrition, foreign bodies, corticosteroid use
avascular necrosis of the femoral head

artery of ligamentum teres closes before medial circumflex femoral artery can supply blood to the femur
What are causes of osteonecrosis?
fracture/trauma, corticosteroid use, vascular insufficiency
What are the causes of osteomyelitis?
hematogenous, post-traumatic w/ direct implantation, overlying ulcers
What are the patheogens of osteomyelitis?
Staph aureus- MC overall
TB- Pott's disease (spine) w/ spread to soft tissue (Psoas abscess)
Salmonella- Sickle cell
Pseudomonas- puncture through rubber shoes
What are the complications of osteomyelitis?
sequestrum-dead bone surrounded by infeciton
involucrum: bone beneath periosteum, surrounding sequestrum
bone abscess
periosteal inflammation w/ spread to soft tissue
septic arthritis
pathological fractures
How does estrogen protect bone in premenopausal women?
estrogen modulates IL-1 (osteoclast activating factor) activit, inhibiting production of osteoclasts and enhancing osteoblasts
What are the complications of osteoporosis?
vertebral body compression fracture
femoral neck fracture
Colles' fracture of dital radiu
What is osteopetrosis?
increased densirty of bone due to genetic defect of osteoclasts
unable to break down bone and unable to remodel weak woven bone

fractures, cranial nerve compression (visual/hearing loss)
pancytopenia due to loss of bone marrow space
Marble bone- weaken woven bone visualized on polarized microscopy

Sclerotic changes on radiograph, ehrlenmeyer flask deformities of long bones, lack of cortical-medullary differentiation
What is Paget's disease of bone?
increased osteoblast and clast activity
targets pelvis, skull, femur
may be viral (paramyxovirus)

osteolysis --> osteoblastic --> sclerotic

enlarged forehead, CNS findings (stenosis of foramen), elevated alk phos

chalk stick fractur
secondary osteoarthritits, increased osteosarcoma
What are secondary causes of osteoarthritis?
jount deformity, systemic disease (hemochromatosis), alkaptonuria, repetitive trauma)
What are the pathological findings with OA?
loss of intra-articular cartilage (Eburnation, sclerosing bone plates)
Osteophytes, subchondral custs, mild lymphoid inflammation in synovium
What is the presentation of OA?
Nodal OA- Heberden-DIP, Bouchard-PIP, Hallux valgus

Axial OA- spinal stenosis and spondylosis

Weight bearing joints- hips and knees
What is the genetic component of RA?
What is the pathogenesis of RA?
RF- IgM aginst Fc receptor of IgG
RF complexes --> complement activation --> destruction of tissue by PMNs

Pannus: hyperplastic synovium secondary to chronic inflammation
--> joint fusion, fibrosis (ankylosis)

Results in joint deformity
What is the presentation of RA?
morning stiffness that improves as day goes on
PIP an dMCP--> ulnar deviation

RA nodules
arterititis, neuropathy, pericarditits, pleuritis, LAD --> lymphoma risk
What are the disease association with RA?
Felty- splenomegaly + neutropenia
Caplain- pneumoconiosis
Sjorgen's RA + Sicca
What is juvenile idopathic arthritis
tends to hit larger joints, less destructive, more liekly to have systemic findings
often RF negative
Systemic JIA (Still's disease): fever, rash, polyarthritis
What is ankylosing spondylitis?
HLA B27 spondylarthropathy
destruction of articular cartilage of the spine --> fusion (bamboo spine)

Lower back pain and stiffness in males 20-30
associated with UC, uveitis, and restrictive lung disease
What is the presentation of gout?
first MTP (podagra)
chronic --> tophio
joint aspirate - yellow, needle shaped, negative birefringence
What are the disease associations of gout?
kidney failure
What is pseudogout?
deposition of Ca pyrophosphate
knee is most common
rhomboid, positive birefringence, blue
What are the MCC of septic arthritis?
staph aureus- children
N. gornorrhea- urban esp C5-C9
Lyme diease-BAKE
Pasturella multocide- cat bite
What is a disk herniation?
nucleus pulposus through annulus fibrosus
posterior herniation will compress nerve fibers
What is osteoid osteoma?
MC benign bone tumor;late peds and young adult
long bones (femur)
night pain from prostaglandins
central area (nidus) of woven bone surrounded by sclerotic bone
What is osteochondroma?
outgrowth of bone off the shaft of a long bone, capped by articular cartilage
What is aneurysmal bone cyst?
tumor full of multinodular cysts and vascular tissue (hemosiderin staining)
What is a giant cell tumor of bone?
histiocyte sand giant cells around KNEE, may become malignant
What is a osteoma?
cortical bone mass found on facial bones, projects in sinus of head
lump of cartilage within shaft of long bone, usually phalanges
What is a osteosarcoma?
MC primary malignant bone tumor
long bones near knee
association w/ Paget's
Codman's triangle
Sunburst appearance
tumor cells making osteoid
Ewing sarcoma?
onion skin aronud bone
small blue cell tumor of undifferentiated cells
What is a fibromatosis?
fibrosis rxn at tendons --> thick tendons become scarred and contract
Palmar- Dupuytren's contracture
Penile- Peyronie's disease
What is a Morton's neuroma?
reactive fibrosis of entrapped nerve
women in high heels
painful bump between metatarsals
What characterizes the myxoid liposarcoma?
younger pt, chicken wire pattern