Flashcards in MSK FIRST AID REVIEW_QUESTIONS MISSED Deck (45):
Most common form of Osteogenesis Imperfecta - transmission? Genes?
Autosomal Dominant: Mutation in 2 collagen A genes: COLA-1 and COLA-2 genes
Defect that causes Osteogenesis Imperfecta?
Caused by a faulty substitution of glycine by a bulky acid in Type I Collagen
Clinical Findings that lead to Osteogenesis Imperfecta? Give a possible clinical scenario for each if possible.
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
Treatment of Osteogenesis Imperfecta?
Bisphosphonates to increase bone mineralization
In Osteogenesis Imperfecta, _______ is defective. Describe what changes to the macromolecular structure of _________.
with the bulky acidic a.a. group substituting glycine in Collagen Type I --> can't form a triple helix
In 3 descriptors, Describe Osteogenesis Imperfecta?
Multiple fractures w/o prior trauma (may occur during birth process for Fx in infants)
Incidence of Osteogenesis Imperfecta
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?
1. Osteogenesis imperfecta
2. Child abuse
Ehrlos-Danlos is a disorder characterized by what Signs/Symptoms?
- Increased range of Motion (Joint hyper-mobility)
- Highly stretchable skin (Cutaneous Fragility and hyper extensibility)
- Dark Pigmentation over bony prominences
What is the classic sign of Ehrlos-Danlos Syndrome (EDS)?
Hyperextension fo the fingers so they are parallel to the extensor surface of the forearm.
What is the major fibrous component of Connective Tissue?
What is the structural unit of collagen? what is its structure?
Tropocollagen, triple helix of alpha-chains (Path, pg. 48)
what is the inheritance pattern of Ehrlos-Danlos Syndrome?
EDS is characterized by a defect in what macromolecule? Types, if any?
Collagen I and III
T/F: EDS is a homogeneous Ds. Explain your choice.
FALSE - EDS is a HETEROGENEOUS disorder, that has a wide range of severity, with EDS Type I < < < EDS Type IV
What is the most severe type of EDS?
Type IV EDS is the most severe
characterized by a decreased amount of Type III Collagen --> structural protein in blood vessels.
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?
Ehrlos Danlos type IV - the most severe type
patients typically have a shortened life span because of spontaneous rupture of large arteries
In a person with Ehrlos-Danlos type IV, why is a headache very concerning?
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.
Which bones are commonly involved in Osteogenesis Imperfecta?
Small bones of hands and feet
Osteogenesis Imperfecta: Ranking of Severity?
Type I < Type II < Type III
Type III are the most severely affected
Bad Type II may die in utero or during parturition
When should Osteogenesis Imperfecta be suspected? (8)
OI should be on the DDx in the presence of any combination of the following:
- bone fragility
- short stature
- basilar skull fractures (think Battle Sign!)
- Blue Sclerae
- Hearing loss
- Dental Abnormalities
- Easy bruising
What is the inheritance pattern of Duchenne Muscular Dystrophy (DMD)?
X-linked recessive (XR)
What is the incidence of Duchenne Muscular Dystrophy?
1/35,00 MALE births
What type of mutation causes Duchenne MD?
frameshift mutation of the dystrophin gene on the X-chromosome
What is the normal action of dystrophin in the muscles?
Dystrophin anchors actin to the membrane glycoprotein
Duchenne vs. Becker Muscular dystrophy: What is the difference in terms of the dystrophin protein?
Duchenne is a complete absence of the protein
Becker is either a partial deficiency or a defective version of the protein
What causes the S/Sx seen with Duchenne MD?
Absence of dystrophin protein --> progressive degeneration of type I and type II fibers
Describe the evolution of "champagne bottle calves" seen in Duchenne MD patients?
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.
When do symptoms normally present in children affected by Duchenne MD?
Between the ages of 2-5 years
What are the S/Sx typically associated with Duchenne MD?
- 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
When do patients with Duchenne MD typically expire? What is usually the cause?
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
Clinical S/Sx of Sjogren's Syndrome?
Dry Eyes: "Sand in my Eyes"
Dry mouth: "Doctor, I can't swallow dry crackers"
One other connective tissue / AIDx: typically Rheumatoid Arthritis
The eye and mouth dryness seen with Sjogren's Syndrome is due to ______?
Autoimmune destruction of the salivary and lacrimal glands
Sjogren's Syndrome is a symptom of what two underlying neoplastic diseases?
Salivary Gland and GI Lymphomas
Classic patient profile in Sjogren's Syndrome?
Female dominant AIDx that commonly presents with rheumatoid arthritis
Why are dental caries a finding in Sjogren's Syndrome?
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.
In serological studies, what tests indicate Sjogren's Syndrome?
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%)
How do you confirm the DDx of Sjogren's Syndrome? What histological pattern do you see?
Lip biopsy --> Lymphoid structures of the minor salivary glands
Treatment of Sjogren's Syndrome?
Pilocarpine or cyclosporine eye drops
Cevimeline (MxR agonist) --> Dry mouth
(+) VDRL test in SLE - Why?
They have so many auto-antibodies that they come up positive
Most specific autoantibodies in SLE?
Most common population for SLE?
women of childbearing age, blacks, asians, hispanics > whites
Environmental triggers for SLE
EBV, UV light, Estrogen, Meds
Skin findings in SLE
Malar "butterfly" rash over cheeks with UV light exacerbation
IF studies = IC deposition along BM in both involved and uninvolved areas