Musculo/Derm 3 Flashcards

1
Q

What is Parathyroid hormone (PTH)?

A

A hormone that increases blood calcium levels by promoting phosphate excretion and stimulating osteoblast activity.

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2
Q

What is the treatment for Rickets and Osteomalacia?

A

Vitamin D and Ca supplementation.

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3
Q

What is the best indicator for Vitamin D status? Why?

A

Serum 25-OH Vit D

It has a long half-life and liver production is not regulated by PTH.

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4
Q

What is the storage form for Vitamin D?

A

25-OH Vitamin D.

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5
Q

What is Paget’s Disease also called?

A

Osteitis Deformans.

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6
Q

Is Paget’s disease a focal or widespread disorder?

A

Focal.

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7
Q

Paget’s Disease is common in what age group?

A

Older patients.

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8
Q

What is the mechanism of Paget’s Disease of the bone?

A

Excessive bone remodeling, believed to be due to abnormal osteoclasts.

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9
Q

What are the 3 phases of Paget’s disease?

A

Initial (Osteolytic), Mixed (Osteolytic-osteoblastic), Final (Osteosclerotic).

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10
Q

What occurs in the Osteosclerotic phase of Paget’s disease?

A

Bone formation dominates and hypervascularity of bone occurs.

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11
Q

What is the hallmark of Bone morphology in Paget’s disease?

A

Mosaic pattern of lamellar bone.

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12
Q

What is the most common complication of Paget’s disease?

A

Chalkstick fracture.

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13
Q

What are 7 clinical features of Paget’s disease?

A

Chalkstick fracture, Bone pain, Bowing of legs, Enlarged skull (increased hat size), Cranial nerve compression, Radiculopathy at spine, Erythema over affected bone area due to hypervascularity.

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14
Q

What is a lab finding in Paget’s disease?

A

Increased bone alkaline phosphatase.

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15
Q

Paget’s disease leads to an increased risk for?

A

Osteosarcoma.

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16
Q

What are 2 treatments for Paget’s disease?

A

Calcitonin, Bisphosphonates.

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17
Q

Osteitis Fibrosa Cystica is a classic bone disease of?

A

Hyperparathyroidism.

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18
Q

Parathyroid adenoma leads to what 3 lab findings?

A

↑ PTH, Hypercalcemia, ↓ Phosphate.

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19
Q

What are 2 X-ray findings in Osteitis Fibrosa Cystica?

A

-Subperiosteal bone resorption: irregular or indented edges to bone
-Brown tumors: collection of giant osteoclasts in bone, appears as black spaces.

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20
Q

What is Renal Osteodystrophy? What does this include?

A

Bone abnormalities seen in renal failure: Osteitis Fibrosa Cystica, Rickets/osteomalacia, Osteopenia/osteoporosis, Growth retardation, Bone pain, Fractures.

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21
Q

What are 4 lab findings in Renal Osteodystrophy?

A

↓ Calcium, ↓ Vitamin D (active form), ↑ PTH, ↑ Phosphate.

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22
Q

What are 4 bone disorders that will have normal Ca2+ and PTH?

A

Osteoporosis, Osteopetrosis, Paget Disease, Bone Tumors.

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23
Q

Does Osteoporosis affect Trabecular or Cortical bone more?

A

Trabecular (high surface area).

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24
Q

What are 3 areas with high trabecular bone content?

A

Spine, Head of femur (hip), Wrist (distal radius).

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25
Q

Osteoporosis is common in what demographic?

A

Elderly white women.

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26
Q

When does peak bone mass occur?

A

Young adulthood.

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27
Q

Why are men less likely to have osteoporosis?

A

They achieve higher peak bone mass.

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28
Q

What is a standard recommendation to prevent Osteoporosis?

A

Weight bearing activity → ↑ bone mass.

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29
Q

What are Calcium, PTH, Alkaline phosphatase findings in Osteoporosis?

A

All normal.

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30
Q

What are Secondary Causes of Osteoporosis?

A

-Glucocorticoids: increase bone resorption, decrease bone formation
-Alcohol
-Smoking: accelerates bone loss
-Phenobarbital, Phenytoin, Carbamazepine
-Unfractionated Heparin (long term)
-Thyroid hormone Replacement: Too high dose → iatrogenic hyperthyroidism
-Hyperthyroidism
-Hyperparathyroidism
-Multiple myeloma
-Malabsorption syndromes (poor absorption of Ca2+/Vit D deficiency).

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31
Q

What is the underlying mechanism of Phenobarbital/Phenytoin causing Osteoporosis?

A

P450 enzymes inducer → Increases breakdown of vitamin D → Less calcium → increased PTH → bone loss.

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32
Q

What test should be performed for a patient on thyroid replacement therapy to minimize progression of bone loss?

A

TSH (if TSH is low then need to lower dose).

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33
Q

What are 2 ways to diagnose Osteoporosis?

A

-Fragility fracture
-T-score of 2.5 or lower on DXA.

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34
Q

What screening test is used for Osteoporosis? Who is this recommended for?

A

-Dual-energy X-ray absorptiometry (DXA) → T score
-Women >65 y/o.

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35
Q

How is a T score obtained in Dual-energy X-ray absorptiometry (DXA)?

A

Compare patient BMD vs. healthy 30 year old BMD (-1.0 or higher is normal).

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36
Q

What are 2 classic areas for fractures in a patient with Osteoporosis?

A

-Hip
-Spine: often occur slowly over time → loss of height, kyphosis.

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37
Q

What are 4 lifestyle modifications for Osteoporosis Therapy?

A

Smoking cessation, Avoid heavy alcohol use, Weight bearing exercise, Ca2+ and vitamin D supplementation.

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38
Q

What is the mechanism of Bisphosphonates?

A

Pyrophosphate analog → binds calcium, accumulate in bone → taken up by osteoclasts → inhibits osteoclasts.

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39
Q

What are adverse effects of Oral Bisphosphonates?

A

Upper GI upset: Reflux, esophagitis, esophageal ulcers.

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40
Q

How should Oral Bisphosphonates be taken? How often are they usually taken?

A

-Take with water on empty stomach
-Remain upright for 30 minutes
-Often taken weekly.

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41
Q

What are adverse effects of IV Bisphosphonates? This can be treated with?

A

Flu-like symptoms (low grade fever, myalgias) → ibuprofen, acetaminophen.

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42
Q

How often is IV Bisphosphonates administered?

A

3-months to annually (Long dosing intervals).

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43
Q

What are 2 uncommon Adverse effects of Bisphosphonates?

A

Atypical femur fractures, Osteonecrosis of the jaw (avascular necrosis).

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44
Q

What are Atypical femur fractures?

A

-Below less trochanter
-Diaphyseal
-No or minimal trauma.

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45
Q

What is Teriparatide? How is it used?

A

Recombinant human PTH, increases osteoblast bone formation

Low dose daily SQ injection.

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46
Q

What are 2 adverse effects of Teriparatide?

A

Brief rise in serum calcium, Theoretical risk of osteosarcoma.

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47
Q

What form of Calcitonin is used in humans?

A

Salmon calcitonin.

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48
Q

What is the mechanism of Denosumab?

A

Monoclonal RANK-L antibody → block osteoclast activation.

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49
Q

Which is more common: Bone metastasis or Primary bone tumor?

A

Bone metastasis.

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50
Q

Where in the bone are Bone metastasis most common?

A

Diaphysis.

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51
Q

What are the 2 types of Metastatic bone lesion? What cancer are they associated with?

A

Osteoclastic lesion: multiple myeloma, Osteoblastic lesion: Prostate carcinoma.

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52
Q

Primary Bone Tumors often occur in?

A

Children/young adults.

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53
Q

Primary Bone Tumors are more common in [M/W]?

A

Men.

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54
Q

Primary Bone Tumors usually involve what bones?

A

Long bones, especially at knees.

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55
Q

Primary Bone Tumors may cause what 2 symptoms?

A

Bone pain, Pathologic fractures (proximal femur and humerus are most frequent sites).

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56
Q

What is Osteoid Osteoma? Where do they commonly occur?

A

Benign small (<2cm) tumor of bone of young men (tumor of osteoblasts)

Occur in appendicular skeleton.

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57
Q

Is Osteoid Osteoma responsive to NSAIDs or aspirin?

A

Yes.

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58
Q

Osteoid Osteoma presents as?

A

Bone pain at night.

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59
Q

Where in the bone does Osteoid Osteoma occur? How does it appear histologically?

A

Surface of cortex of diaphysis

Osteoid core with rim of woven bone.

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60
Q

How does Osteoid Osteoma appear on X-ray?

A

Bump on the edge of the bone with central osteoid core.

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61
Q

Osteoblastoma often involves what bone?

A

Spine.

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62
Q

Is pain from Osteoblastoma responsive to NSAIDs or aspirin?

A

No.

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63
Q

What is the gene mutation in Gardner’s Syndrome?

A

APC gene mutation.

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64
Q

Gardner’s Syndrome is a variant of?

A

Familial Adenomatous Polyposis.

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65
Q

What bone manifestation often occurs in Gardner’s syndrome? Where do they usually occur?

A

Osteomas, usually in skull or mandible.

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66
Q

What is the most common primary bone tumor?

A

Osteosarcoma.

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67
Q

Osteosarcoma is a malignant bone tumor of?

A

Osteoblasts.

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68
Q

What is the age distribution of Osteosarcoma?

A

Bimodal: 75% young adults, 25% older adults (i.e. Paget’s).

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69
Q

Histopathology of Osteosarcoma?

A

Pleomorphic cells with irregular osteoid formation (pink).

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70
Q

What is the clinical presentation of Osteosarcoma? Where do they commonly occur?

A

Painful, enlarging mass on bone usually in metaphysis of long bones

50% occur at knee (distal femur, proximal tibia).

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71
Q

What are 2 classic X-ray findings in Osteosarcoma?

A

Codman triangle: Tumor breaks through cortex and lifts periosteum, Sunburst sign.

72
Q

Osteosarcoma is associated with what conditions?

A

Pagets, Prior radiation, Familial retinoblastoma (Rb gene mutation), Li Fraumeni syndrome (p53 tumor suppressor gene).

73
Q

What is the treatment for Osteosarcoma?

A

Always treated with chemotherapy prior to surgery (poor prognosis with surgery alone)

“En bloc” resection: Removal of entire tumor in one piece with a layer of healthy tissue.

74
Q

What is Ewing Sarcoma?

A

Malignant bone tumor of undifferentiated neuroectoderm cells.

75
Q

Ewing Sarcoma usually presents during?

A

Childhood (80% <20 y/o).

76
Q

Ewing Sarcoma occurs in what part of the bone? Most commonly which bone?

A

Diaphysis of long bones, most commonly femur.

77
Q

Is Ewing Sarcoma aggressive?

A

Yes.

78
Q

What is the clinical presentation of Ewing Sarcoma? It can be confused with?

A

Fever, leukocytosis, painful growing mass over bone

Osteomyelitis.

79
Q

How to differentiate Ewing Sarcoma and Osteomyelitis?

A

Blood cultures and tumor aspiration: sterile.

80
Q

What is a classic x-ray finding of Ewing Sarcoma?

A

Onion skin (splitting/thickening of cortex).

81
Q

Histopathology of Ewing Sarcoma?

A

Sheets of small round blue cells.

82
Q

Ewing Sarcoma is associated with what genetic mutation?

A

Genetic translocation: Fusion of EWSR1 gene(22) to FLI1 gene (11).

83
Q

Giant Cell tumor is also called?

A

Osteoclastoma.

84
Q

Is Giant Cell tumor malignant?

A

No, but locally aggressive.

85
Q

Giant Cell tumor usually occurs in what part of the bone? Where is it most common?

A

Epiphysis, most commonly at knee.

86
Q

The stromal tumor cells in Osteoclastoma express high levels of?

A

RANK-L → drives osteoclast activity.

87
Q

Giant Cell tumor Histopathology?

A

Multi-nucleated giant osteoclasts.

88
Q

What is Osteochondroma?

A

Benign cartilage forming tumor.

89
Q

When do Osteochondroma occur? Are they more common in M/W?

A

Early adulthood, men.

90
Q

Osteochondroma on X-ray will present as?

A

Cartilage-capped bone spur.

91
Q

Osteochondroma arise from the?

A

Growth plate (metaphysis).

92
Q

Osteochondroma stop growing with?

A

Growth plate closure.

93
Q

Osteochondroma is treated with?

A

Simple excision.

94
Q

What is Fibrous Dysplasia? Where does it occur in the bone?

A

Benign tumor, fibrous tissue replaces bone

Occurs in medulla/diaphysis.

95
Q

What is a histopathologic finding of Fibrous Dysplasia?

A

“Chinese character” Trabeculae of woven bone.

96
Q

What is an X-ray finding of Fibrous Dysplasia?

A

Lytic lesion in diaphysis.

97
Q

What are Simple bone cysts? Where are they common?

A

Fluid-filled spaces with fibrous lining

Proximal humerus and femur.

98
Q

What is the treatment for Simple bone cysts?

A

Observation with serial X-rays, often spontaneously improves.

99
Q

Where in the bone are Simple bone cysts found?

A

In metaphysis.

100
Q

Chondroma occurs in what bone?

A

Small bones of hands and feet.

101
Q

Chondromas in the medullary cavity are called?

A

Endochondromas.

102
Q

Chondromas on the surface of bone are called?

A

Juxtacortical chondromas.

103
Q

Where does Chondrosarcoma often occur? Where in the bone?

A

Occur centrally (pelvis, shoulder, ribs)

Medulla.

104
Q

Calcium and PTH levels in bone tumor?

A

Normal.

105
Q

Bone mass in the skull with Eosinophils present suggests?

A

Langerhans Cell Histiocytosis- Eosinophilic granuloma.

106
Q

Cell within Eosinophilic granuloma express what 3 markers?

A

CD1a, S100, CD207.

107
Q

What is the most common type of arthritis?

A

Osteoarthritis.

108
Q

Articular cartilage is composed of what type of collagen?

A

Type II.

109
Q

What is a major component of synovial fluid?

A

Hyaluronic acid.

110
Q

What leads to the development of Osteoarthritis?

A

Hyaline cartilage breakdown, Abnormal chondrocytes: proliferate in OA but inadequate repair → eventually die and expose bone.

111
Q

Osteoarthritis present with [low/high] WBC in synovial fluid?

A

Low (non-inflammatory arthritis).

112
Q

What are 4 X-ray findings seen in Osteoarthritis?

A

Joint space narrowing, Subchondral sclerosis, Osteophytes (bone spurs), Subchondral cyst.

113
Q

What is the main component of synovial fluid?

A

Hyaluronic acid

114
Q

What leads to the development of Osteoarthritis?

A

Hyaline cartilage breakdown
Abnormal chondrocytes: proliferate in OA but inadequate repair → eventually die and expose bone

115
Q

Osteoarthritis presents with [low/high] WBC in synovial fluid.

A

low (“non inflammatory arthritis”)

116
Q

What are 4 X-ray findings seen in Osteoarthritis?

A

Joint space narrowing
Subchondral sclerosis
Osteophytes (bone spurs)
Subchondral cyst

117
Q

What are Osteophytes?

A

Bone spurs, thickening of subchondral bone at joint margins

118
Q

How are Subchondral cysts formed?

A

Bone cracks → synovial fluid accumulation

119
Q

Osteoarthritis often involves what joints?

A

Both knees: medial knee affected more
DIP and PIP joints, 1st Carpometacarpal joint
Facet joints in lower cervical and lumbar spine
Hip

120
Q

Where do Heberden’s and Bouchard’s nodes occur?

A

Heberden’s: DIP
Bouchard’s: PIP

121
Q

Nodal osteoarthritis is believed to be caused by?

A

osteophytes

122
Q

What are 3 symptoms of Osteoarthritis?

A

Joint pain
Stiffness
Restricted motion

123
Q

Joint pain in Osteoarthritis improves with [rest/activity].

A

rest

124
Q

Joint pain in Osteoarthritis is usually worst at?

A

end of day for weight bearing joint

125
Q

What are 4 risk factors for Osteoarthritis? Which is modifiable?

A

Old age
Female
Obesity: modifiable
Joint injuries

126
Q

What is the treatment for Osteoarthritis?

A

Exercise
Weight loss
Pain control: Acetaminophen, NSAIDs
Intraarticular glucocorticoid injection: controversial
Surgery

127
Q

What are 5 differences between Rheumatoid arthritis and Osteoarthritis?

A

RA:
Women 40-50
High synovial WBC
Joint pain improves with activity
Morning stiffness
Systemic complications: uveitis, serositis, Baker’s cyst

128
Q

What is the clinical presentation of Septic Arthritis?

A

Acute onset
Swelling and pain usually of single joint
Fever, chills, sweats

129
Q

What are 3 pathogens commonly responsible for Septic arthritis?

A

S. aureus
S. pneumoniae
Neisseria gonorrhoeae

130
Q

Patient with Acute monoarthritis must consider what 3 conditions?

A

Septic arthritis, gout, pseudogout

131
Q

Arthritis in Hemochromatosis commonly affects what joint?

A

MCP joint

132
Q

What is a key lab finding of Hemochromatosis?

A

high serum ferritin (iron overload disorder)

133
Q

What is gout? What are the symptoms and what is the mechanism?

A

Monosodium uric acid deposition in joints
Crystals phagocytosed → trigger inflammatory response → severe joint pain, swelling warmth

134
Q

Gout most commonly involves what joint? It can also occur in?

A

1st MTP joint
Knee

135
Q

What are 3 factors required for gout development?

A

Hyperuricemia + cool temperatures + genes

136
Q

What is a Tophi?

A

uric acid collections in connective tissue (ears, tendons, bursa), not painful

137
Q

Chronic Tophaceous Gout is seen with?

A

long standing gout

138
Q

Chronic gout can lead to what renal condition? What does this lead to?

A

Urate nephropathy: Uric acid crystals in urine → uric acid stones → chronic renal failure

139
Q

What is primary gout? What is it associated with?

A

Gout not due to any other disease or medication
Associated with under excretion of uric acid

140
Q

Uric Acid Excretion is mostly through?

A

the kidneys

141
Q

What leads to a decrease in uric acid excretion? What are 3 examples?

A

Reduction in GFR: renal failures, volume depletion, diuretics

142
Q

What are 2 common purine sources that can cause gout attack?

A

Red meat/Seafood
Trauma/surgery (tissue breakdown)

143
Q

What are the 2 mechanisms by which Alcohol can trigger gout?

A

Metabolism consumes ATP → uric acid
Lactic acid from alcohol metabolism increases Urate transporter-1 (URAT1) activity → Increased reabsorption of uric acid

144
Q

Gout attacks are more common among what type of patients?

A

Obese males

145
Q

Classic case of gout presents as?

A

an obese male after steak dinner with heavy alcohol consumption

146
Q

What enzyme is defective in Lesch Nyhan Syndrome? What is the inheritance pattern?

A

HGPRT, X-linked

147
Q

HGPRT is an enzyme involved in?

A

purine salvage pathway

148
Q

Clinical presentation of Lesch-Nyhan syndrome?

A

Excess uric acid production (“juvenile gout”)
Neurologic impairment
Hypotonia, chorea
Self mutilating behavior

149
Q

What enzyme deficiency is seen in Von Gierke’s Disease?

A

Glucose-6-phosphatase deficiency (Glycogen Storage Disease Type I)

150
Q

What is the clinical presentation of Von Gierke’s Disease?

A

Severe hypoglycemia between meals → Seizures, Lactic acidosis
Lactic acidosis increases URAT1 activity → increased reabsorption

151
Q

How to diagnose gout?

A

Arthrocentesis → polarized light microscopy, high WBC count

152
Q

How do gout crystals appear under polarized light microscopy?

A

“Negatively birefringent”
Yellow when parallel to axis of the polarization
Blue when perpendicular to polarization axis

153
Q

What are 3 drugs used for acute Gout attacks?

A

NSAIDs
Glucocorticoids
Colchicine

154
Q

What are 3 drugs used for Gout prevention?

A

Xanthine oxidase inhibitors (allopurinol, febuxostat)
Pegloticase
Probenecid

155
Q

What is the mechanism of Colchicine?

A

Binds to tubulin → prevents polymerization of microtubules (microtubule inhibitor)
Inhibits WBC migration and phagocytosis

156
Q

What is the mechanisms of Allopurinol and Febuxostat?

A

Xanthine Oxidase inhibitor:
Allopurinol: competitive
Febuxostat: non-competitive

157
Q

What are 2 clinical uses for Xanthine Oxidase inhibitors?

A

Gout
Prevent Tumor lysis syndrome

158
Q

For gout treatment, Xanthine Oxidase Inhibitors are initiated together with what drug? Why?

A

NSAIDs/Colchicine
Abrupt change in serum uric acid levels may precipitate a gout attack

159
Q

Allopurinol and Febuxostat can increase toxicity of what 2 drugs?

A

Azathioprine and 6-MP

160
Q

What is the mechanism of Pegloticase? What is the route of administration?

A

Recombinant uric acid oxidase (degrades uric acid) attached to polyethylene glycol which prolongs half-life
IV

161
Q

Pegloticase converts uric acid into?

A

allantoin (excreted by kidneys)

162
Q

What is the mechanism of Rasburicase?

A

Recombinant uricase (converts uric acid to allantoin)

163
Q

What is the clinical use for Rasburicase?

A

Tumor lysis syndrome

164
Q

What are 4 lab findings seen in Tumor Lysis Syndrome?

A

Hyperkalemia → arrhythmias
Hyperphosphatemia → hypocalcemia
Hyperuricemia → uric acid nephropathy/acute renal failure

165
Q

What are 2 effects of Probenecid? What is an Adverse effect?

A

Blocks proximal tubules reabsorption of uric acid (uricosuric)
Blocks secretion of penicillin

A/E: uric acid kidney stones

166
Q

What is the effect of high dose vs low dose aspirin in gout?

A

High dose: inhibits secretion and reabsorption of uric acid (uricosuric)
Low dose: inhibits secretion of uric acid → hyperuricemia

167
Q

Is Low dose aspirin use for pain control in gout?

A

No

168
Q

What is the cause of Calcium Pyrophosphate Deposition Disease?

A

unknown

169
Q

Calcium Pyrophosphate Deposition Disease occurs in [younger/older] patients.

A

older (average 72 y/o)

170
Q

What are 3 clinical patterns of Calcium Pyrophosphate Deposition Disease?

A

Asymptomatic (discovered on imaging)
Acute arthritis (similar to gout)
Chronic joint disease (similar to OA)

171
Q

What is a X-ray finding seen in Asymptomatic Calcium Pyrophosphate Deposition Disease?

A

Chondrocalcinosis: calcification of hyaline cartilage

172
Q

What is pseudogout? What joint is commonly involved?

A

Acute attack of arthritis seen in Calcium Pyrophosphate Deposition Disease
50% of cases involved knees

173
Q

Pseudogout is provoked by [3]. May flares are reported after?

A

Trauma, surgery, medical illness
Parathyroidectomy

174
Q

Pseudogout visualized under Polarized Light Microscopy will appear as?

A

Rhomboid crystals, positively birefringent
Blue when parallel to light (yellow for gout)

175
Q

What is the treatment for acute pseudogout attack?

A

NSAIDs, colchicine, or glucocorticoids