Thursday night highlights - high yield Flashcards
mechanism of Guillan Barre
destroys myelin in patchy manner
Most common etiology of a mononeuropathy
compression of nerve –> demyelination at the site of compression (think carpal tunnel syndrome)
fasciculations are a ___sign (LMN/UMN)
LMN
which is more common - axonal neuropathies or demyelinating myopathies?
axonal, by a long shot.
Case: decreased sensation on right thumb, right index finnger, right middle finger, and part of ring finger. Worsened by typing / holding the steering wheel. Normal reflexes. Which nerve?
Median nerve - carpal tunnel.
Remember - median is mixed - sensory and motor sx
Radial mononeuropathy - symptoms and common cause
wrist drop - saturday night palsy (pass out with humerus impacted)
Peroneal mononeuropathy - symptoms and common cause
foot drop - sitting with legs crossed.
3 viruses that cause guillan barre
campylobacter, CMV, EBV
mechanism of guillan barre -
cross reaction of ab’s with gangliosides in myelin/schwann cells.
can improved glucose control reverse diabetic neuropathy?
nope. but but can prevent progress.
What are fasciculations?
visible mm twitching
LMN sign
cramps - LMN or UMN?
LMN
Muscle spasticity - UMN or LMN?
UMN
Atrophied tongue with fasciculations - which disease
hallmark of ALS
T/F - in diabetic neuropathy myelin is affected. In guillan barre, axons are affected.
False. Reverse
clinical characteristics of mm disorders
diffuse/proximal weakness - usually symmetric!!
normal sensation
normal reflexes (if mm strong enough)
characteristics of congenital myopathies - 3
inherited
- NON-progressive/slowly progressive
- disorders of the contractile mechanism of skeletal mm
What is the example disease for a muscular dystrophy caused by nuclear transcription abnormalities>
Fascioscapulohumeral muscular dystrophy (FSHD)
What is the example disease for a disorder of mm contraction?
Congenital fiber type disproportion.
Limb girdle muscle dystrophies are separated into 1s and 2s. Which one is dominant?
1 = dominant
2- recessive,
x linked = duchenne becker.
what does the dystrophin glycoprotein complex do?
It connects the contractile elements of the mm cell to the extracellular matrix
when does duchenne MD present?
3-5yo. wheelchair by 12
duchenne becker MD is x linked _____
recessive
how do people with duchenne MD typically present?
3-5 years old
gross motor delay
trouble walking / running
which type of muscle dystrophy can present in adulthood?
becker
t/f - 95% of duchenne/becker muscular dystrophy pt’s can be diagnosed by genetic testing, without mm biopsy
True
calf hypertrophy - which disease?
Duchenne MD
Mechanism of Fascioscapulohumeral muscular dystrophy (FSHD)
deletion within a repetitive sequence on chromosome 4 –> DUX4
clinical presentaiton of Fascioscapulohumeral muscular dystrophy (FSHD)
young - 8 years old -chicken wings -trouble lifting things -sleep w/ whites of eyes showing -bilateral facial weakness. "refuses to smile for family photos" -CK normal
Which gene mutation is the most common culprit in congenital myopathies like nemaline, etc?
RYR1 (ryanodine receptor).
plays a role in excitation / contraction coupling
categories of congenital myopathies with characteristic path
Core - mitochondria extruded
nemaline - blue dots in cells
Lack of eye mvmts in early child - probably?
congenital myopathy - other diseases rarely affect eyes. - Congenial fiber disproportion!
What is a chronic soft tissue injury in youth?
osgood schlatters
Presentation of osgood schlatters
10-15 years old.
palpable bump on front of knee.
caused by overuse - jumping too much, kiddo?
Mechanism of osgood schlatters
Repeated microfractures on tibia not given a chance to heal. Tears where the patellar tendon meets the bone.
What does a stress fracture look like on X ray?
fuzzy stuff around the bone (bone attempting to reheal)
Imaging for proximal thigh stress fracture
x ray
bone scan if x ray negative.
definition of a sprain
injury to ligament
definition of a strain
injury to a tendon (sprain a joint, strain a muscle/tendon)
how do you classify sprains?
by ligament laxity.
mild- pain but no laxity
moderate - lax with an end-point (partial tear)
severe= gross laxity (feels like you could dislocate it if you want) = complete tear
what is the most common ankle sprain? It is due to which motion?
anterior talofibular ligament.
due to infersion
In an anterior talofibular ligament sprain tenderness will be in which area?
laterally, near the distal fibula and talar neck
what test should be done for inversion ankle sprains?
Anterior drawer test. If it is positive talofibular ligament broken
If you suspect calcaneofibular ligament injury - what test do you do?
Talar tilt
severe inversion ankle sprain - which ligaments affected?
anterior talofibular
calcaneofibular
How many ankle sprains need x rays?
10% if trainer present.
15-30% in Emergency room.
what are the indications for an x ray of an ankle? (These are the Ottowa rules)- 4
gross swelling
point tender over posterior or distal fibula
-crepitus
-can’t bear weight
Tib-fib sprain - exam findings
ankle external rotation painful (eversion)
- tender above the ankle on the tibia
- can’t walk/push off.
most common knee sprain
MCL
characteristics of MCL knee sprain
- no joint swelling (MCL is outside the joint)
- sensitive to valgus force
Woman playing soccer. When she planted her foot, she heard a painful pop and then her knee shifted. Likely diagnosis?
ACL. Check for hemarthrosis (knee swelling)
A patient has hemarthrosis of the knee.(Swelling) what is the most likely injury? + 2 other less common
70% chance of ACL tear.
Meniscus #2
Articular surface fracture #3
Exam test for ACL tear?
Lachman (anterior drawer at 30 degrees bent.
What is the key physical exam finding for a meniscus tear? How sensitive / specific?
McMurray’s - rotate the leg around, hear a pop. Least sensitive most specific.
Which is worse - dislocation or subluxation?
Dislocation.
Subluxation is pathologic movement of the joint, short of dislocation.
Which upper extremity injury is associated with the positive apprehension test?
Shoulder dislocation (glenohumeral separation)
lachman’s test?
for ACL - similar to anterior drawer
Which lower extremity injury associated with apprehension sign?
patellar dislocation
In adolescent idiopathis sccoliosis (AIS), which Cobb angles should be treated with braces? What about surgery?
25-40 degrees = brace.
>50 degrees = surgery
lumbar radiculopathy at the L5 level will cause weakness where?
ankle/toe
What explains why structure does not equal function in regards to back pain?
Biopsychosocial model
Mechanism for Marfan
mutation in fibrillin 1 gene (auto dominant) - cannot form microfibrils - defective elastic fibers lead to more TGF-beta accessible - increased growth!!