MSK FIRST AID REVIEW_QUESTIONS MISSED

Question 1

Most common form of Osteogenesis Imperfecta - transmission? Genes?

Answer 1

Autosomal Dominant: Mutation in 2 collagen A genes: COLA-1 and COLA-2 genes

Question 2

Defect that causes Osteogenesis Imperfecta?

Answer 2

Caused by a faulty substitution of glycine by a bulky acid in Type I Collagen

Question 3

Clinical Findings that lead to Osteogenesis Imperfecta? Give a possible clinical scenario for each if possible.

Answer 3

1. Pathologic features at birth: “normal healthy baby, but fractures in large bones without a prior history of trauma”
2. Blue sclera: reflection of the underlying choroidal veins through the thin sclera
3. Deafness in some patients: Deformity of middle ear bones
4. Dental imperfections –> lack of dentin

Question 4

Treatment of Osteogenesis Imperfecta?

Answer 4

Bisphosphonates to increase bone mineralization

Question 5

In Osteogenesis Imperfecta, _______ is defective. Describe what changes to the macromolecular structure of _________.

Answer 5

with the bulky acidic a.a. group substituting glycine in Collagen Type I –> can’t form a triple helix

Question 6

In 3 descriptors, Describe Osteogenesis Imperfecta?

Answer 6

Multiple fractures w/o prior trauma (may occur during birth process for Fx in infants)
Blue sclera
Hearing Loss

Question 7

Incidence of Osteogenesis Imperfecta

Answer 7

1/10,000

Question 8

A 6 y/o boy is brought into the ED with a femoral fracture. when you send him for an X-ray, you note multiple healed fractures in multiple bones. What two states/conditions can be attributed?

Answer 8

1. Osteogenesis imperfecta

2. Child abuse

Question 9

Ehrlos-Danlos is a disorder characterized by what Signs/Symptoms?

Answer 9

• Increased range of Motion (Joint hyper-mobility)
• Highly stretchable skin (Cutaneous Fragility and hyper extensibility)
• Dark Pigmentation over bony prominences

Question 10

What is the classic sign of Ehrlos-Danlos Syndrome (EDS)?

Answer 10

Hyperextension fo the fingers so they are parallel to the extensor surface of the forearm.

Question 11

What is the major fibrous component of Connective Tissue?

Answer 11

collagen

Question 12

What is the structural unit of collagen? what is its structure?

Answer 12

Tropocollagen, triple helix of alpha-chains (Path, pg. 48)

Question 13

what is the inheritance pattern of Ehrlos-Danlos Syndrome?

Answer 13

Mendelian

Question 14

EDS is characterized by a defect in what macromolecule? Types, if any?

Answer 14

Collagen I and III

Question 15

T/F: EDS is a homogeneous Ds. Explain your choice.

Answer 15

FALSE - EDS is a HETEROGENEOUS disorder, that has a wide range of severity, with EDS Type I < < < EDS Type IV

Question 16

What is the most severe type of EDS?

Answer 16

Type IV EDS is the most severe

characterized by a decreased amount of Type III Collagen –> structural protein in blood vessels.

Question 17

A 4-month pregnant woman arrives in the ER due to a uterine rupture. You also see that she is very flexible, showing you that she can even bend her fingers back towards her wrist. She is worried about the laxity of her hips, as she dislocated it easily before arriving at the ER (scaring the EMTs!). You suspect that she has a collagen Disorder - which one?

Answer 17

Ehrlos Danlos type IV - the most severe type

patients typically have a shortened life span because of spontaneous rupture of large arteries

Question 18

In a person with Ehrlos-Danlos type IV, why is a headache very concerning?

Answer 18

Because of the Collagen III being in such low [ ] in the vessels - the probability of rupture is very high. In the setting of headache and this (+) PMH - a headache is concerning because we would suspect a possible arterial rupture or aneurysm.

Question 19

Which bones are commonly involved in Osteogenesis Imperfecta?

Answer 19

Long bones
Arms
Ribs
Small bones of hands and feet

Question 20

Osteogenesis Imperfecta: Ranking of Severity?

Answer 20

Type I < Type II < Type III

Type III are the most severely affected
Bad Type II may die in utero or during parturition

Question 21

When should Osteogenesis Imperfecta be suspected? (8)

Answer 21

OI should be on the DDx in the presence of any combination of the following:

• bone fragility
• scoliosis
• short stature
• basilar skull fractures (think Battle Sign!)
• Blue Sclerae
• Hearing loss
• Dental Abnormalities
• Easy bruising

Question 22

What is the inheritance pattern of Duchenne Muscular Dystrophy (DMD)?

Answer 22

X-linked recessive (XR)

Question 23

What is the incidence of Duchenne Muscular Dystrophy?

Answer 23

1/35,00 MALE births

Question 24

What type of mutation causes Duchenne MD?

Answer 24

frameshift mutation of the dystrophin gene on the X-chromosome

Question 25

What is the normal action of dystrophin in the muscles?

Answer 25

Dystrophin anchors actin to the membrane glycoprotein

Question 26

Duchenne vs. Becker Muscular dystrophy: What is the difference in terms of the dystrophin protein?

Answer 26

Duchenne is a complete absence of the protein Becker is either a partial deficiency or a defective version of the protein

Question 27

What causes the S/Sx seen with Duchenne MD?

Answer 27

Absence of dystrophin protein --> progressive degeneration of type I and type II fibers

Question 28

Describe the evolution of "champagne bottle calves" seen in Duchenne MD patients?

Answer 28

this findings if caused by the fibrosis and fatty infiltrate into the gastrocnemius muscle tissue, thus producing the pseudohypertrophy of the calf muscles. this will produce the classic sign of "champagne bottle calves" of Duchenne children.

Question 29

When do symptoms normally present in children affected by Duchenne MD?

Answer 29

Between the ages of 2-5 years

Question 30

What are the S/Sx typically associated with Duchenne MD?

Answer 30

- Weakness and wasting of pelvic muscles - Gower Maneuver - Waddling (duck-like) gait - Cardiac involvement: Cardiomyopathy --> heart failure and arrythmias Respiratory muscle weakness eventually leads to respiratory failure

Question 31

When do patients with Duchenne MD typically expire? What is usually the cause?

Answer 31

Typically patients w/ Duchenne will have a progressive weakness of their respiratory muscles, leading to respiratory failure. the average age of death is 20 y/o

Question 32

Clinical S/Sx of Sjogren's Syndrome?

Answer 32

Dry Eyes: "Sand in my Eyes" Dry mouth: "Doctor, I can't swallow dry crackers" Dental Caries One other connective tissue / AIDx: typically Rheumatoid Arthritis

Question 33

The eye and mouth dryness seen with Sjogren's Syndrome is due to ______?

Answer 33

Autoimmune destruction of the salivary and lacrimal glands

Question 34

Sjogren's Syndrome is a symptom of what two underlying neoplastic diseases?

Answer 34

Non-Hodgkin Lymphoma | Salivary Gland and GI Lymphomas

Question 35

Classic patient profile in Sjogren's Syndrome?

Answer 35

Female dominant AIDx that commonly presents with rheumatoid arthritis

Question 36

Why are dental caries a finding in Sjogren's Syndrome?

Answer 36

Sjogren's Syndrome presents with auto-immune destruction of the salivary glands. Saliva, however, is essential at maintaining the oral pH ~7.0. If this doesn't happen, then bacterial acids will start leaching Ca2+ from enamel, thus leading to caries.

Question 37

In serological studies, what tests indicate Sjogren's Syndrome?

Answer 37

Positive ANA --> tells you there is an AIDx Positive serum RF [90%] - this is a non-specific test that tells you there is a connective tissue inflammation disorder afoot Anti-SS-A antibodies (Anti-Ro; 70%-95%) Anti-SS-B antibodies (Anti-La; 60-90%)

Question 38

How do you confirm the DDx of Sjogren's Syndrome? What histological pattern do you see?

Answer 38

Lip biopsy --> Lymphoid structures of the minor salivary glands

Question 39

Treatment of Sjogren's Syndrome?

Answer 39

Artificial tears Pilocarpine or cyclosporine eye drops Cevimeline (MxR agonist) --> Dry mouth

Question 40

(+) VDRL test in SLE - Why?

Answer 40

They have so many auto-antibodies that they come up positive

Question 41

Most specific autoantibodies in SLE?

Answer 41

Anti-Smith | Anti-dsDNA

Question 42

Most common population for SLE?

Answer 42

women of childbearing age, blacks, asians, hispanics > whites

Question 43

Environmental triggers for SLE

Answer 43

EBV, UV light, Estrogen, Meds

Question 44

Skin findings in SLE

Answer 44

Malar "butterfly" rash over cheeks with UV light exacerbation IF studies = IC deposition along BM in both involved and uninvolved areas

Question 45

Musculoskeletal findings in SLE

Answer 45

Arthralgia -most common complaint morning stiffness in hands - very common Arthritis - most common in PIP and MCP joints of hands and wrists Typically symmetric and non-erosive and non-deforiming (unlike Rheumatoid Arthritis = deforming)