Muscle / Skin Flashcards
Where do ACL and PCL attach?
ACL: anterior tibia
PCL: posterior tibia
What is anterior drawer?
If ACL is busted, tibia moves freely anteriorly if you pull on it
What are varus and valgus force testing?
Varus: medially directed force on tibia, Testing LCL
Valgus: laterally directed force on tibia, testing MCL, if torn, will ABduct
- Think if the ligaments as a hinge, if one is broken it allows it to swing open like a door in direction of pressure away from tear
What is meniscus?
Cartilage between tibia and femur: medially it is attached to MCL making it less mobile
How to test for meniscal tear?
Mcmurray test: rotation of tibia when knee at 90
- Pain on internal rotation (toes to midline): lateral meniscal tear
- Pain in external rotation: medial meniscal tear
What is the unhappy triad?
Traumatic injury to lateral knee causing:
- MCL
- ACL
- Lateral meniscus “LAME” LAteral MEniscus
What is housemaid’s knee?
“Prepatellar bursitis”
- Too much kneeling = swollen / painful bursa of patella
What is a baker’s cyst?
- Cystic lesion in knee pit area
- Can cause DVT if large enough
Muscles in the rotator cuff? Functions?
“SITS”
Supraspinatus: First 15 ABduction (deltoid after)
Infraspinatus: Lateral rotation of arm
Teres minor: ADduction / lateral rotation
Subscapularis: Medial rotation / ADduction
What is injury if cant abduct arm, but if you place on cheir or give it a boost then you can?
Tear in supraspinatus as this is responsible for first 15 degrees of lifting then the deltoid takes over
What muscle provides the following arm motion:
First 15 ABduction (deltoid after)
Supraspinatus
What muscle provides the following arm motion:
Lateral rotation of arm
Infraspinatus
What muscle provides the following arm motion:
ADduction / lateral rotation
Teres minor
What muscle provides the following arm motion:
Medial rotation / ADduction
Subscapularis
Cause of medial epicondylitis?
- Golf
2. Pitching
What causes lateral epicondylitis?
- Tennis elbow: from backhand motion
Bone injured when pain on snuffbox pressure?
Scaffoid
Dislocation of what bone can cause carpal tunnel?
Lunate can lead to median nerve compression
What happened if ulnar injury after fall on outstretched hand?
Hamate bone injury: think, you fell on your outstretched arm because you were trying to “Ham it up”
Where is carpal tunnel numbness experienced?
- Thumb
- First finger
- Middle finger
- half of ring finer
3 associations of carpal tunnel?
- Pregnancy
- RA
- HYPOthyroid
What is guyon canal syndrome and what causes?
- Injury to ulnar nerve from leaning on palm
Nerve roots of brachial plexus?
C5 - T1
Where does C8 nerve come out?
Below C7, all other cervical nerves come out above their respective vertebrae
What does posterior cord lesion cause?
Problem with extension as it splits into axial and radial nerve
Dermatomes of hand?
C6 - 8 as you move from thumb to pinky
- Middle finger is C7 only
Sensory innervation of palm?
Ulnar: pinky and half of third finger
Median nerve: thumb and 2.5 fingers
Sensory innervation of dorsal hand?
Ulnar: pinky / half of third finger (same as palmar surface)
Median: tips of thumb and 2.5 fingers
Radial: lower portion thumb and 2.5 fingers down to wrist
What is saturday night palsy?
- Fall asleep with arm over chair compressing radial nerve leading to wrist drop and numbness
Another name for radial never?
Great extensor
Where is radial nerve often compressed?
Spiral groove of humerus in the axilla
- Can be caused with arm over chair or use of crutches
What would direct trauma to tip of shoulder cause?
Upper trunk injury: “Herbs / waiter’s palsy”
- Deltoids, biceps, brachialis paralyzed
- Arm hangs down and medially rotated
- No elbow flexion / supination
Cause of lower trunk injury?
- Grabbing branch on fall
- Pulling babies arm in labor
- Pancoast tumor of lung
- Additional cervical rib
* Leads to monkeys grip
Where is proximal radial nerve located?
Axilla
When does radially nerve move radially?
Just past elbow
Injury in elbow dislocation?
Deep branch radial nerve: loss of innervation of extensor wrist muscles: wrist drop
Route of axillary nerve?
Hugs surgical neck of humerus?
What nerve hugs surgical neck of humerus?
Axillary
Nerve in spiral groove of humerus?
Radial
Nerve injured in fracture of humeral head?
Axillary
Nerve injury in anterior dislocation of humerus?
Axillary as wraps around humeral head
Injury if can abduct arm after 15 degrees?
Deltoid from anterior dislocation of shoulder injuring axially nerve
Nerve that innervates deltoid?
Axillary nerve
How would musculocutaneous nerve injured and what would signs be?
- Carrying heavy backpack: innervates brachioradialis so you can flex arm and will have numb patch of skin on forearm
What compressed if supracondylar fracture of humerus?
Median nerve
What does long thoracic innervated?
Serratus anterior: leads to winged scapula
Function of lumbricals?
- Flex MCP joint
2. Extend DIP / PIP
What does distal lesion to median or ulnar nerve cause?
“Clawhand” flexion at DIP / PIP
- Lumbrical extension of DIP / PIP is loss so flexors are exaggerated
What is ulnar claw?
- Distal ulnar injury = loss of function to medial lumbricals
= claw of 3/4th fingers
aka “pope’s blessing sign “
Injury if try to make fist and thumb, 1/2 second fingers wont close?
Proximal medial nerve lesion
Injury if you can’t extend first second fingers?
- Distal median nerve lesion
Injury if can’t close pinky and 4th finger?
Proximal ulnar nerve
Injury if you can’t move thumb away from hand?
Opponens pollicis injury innervated by proximal medial nerve
Lesion causing total claw?
Lower trunk lesions C8 - T1 of brachial plexus
What is thenar eminence and muscles found in it?
Area of palm by thumb: “OAF”
- Opponens pollicis
- Abductor pollicis
- Flexor pollicis brevis
* **All innervated by medial “million dollar” nerve
Nerve to hypothenar eminence?
Ulnar
- OAF as in thenar eminence but this is digiti minimi instead of pollicis
What do dorsal / palmar interossei do?
“DAB / PAD”
Dorsal: ABduct
Palmar: ADduct
What gives rise to tibial and common peroneal nerves?
Tibial: Sciatic
Peroneal: Sciatic
What does obturator innervated?
- Medial thigh muscles: adduct thigh
- Sensory innervation of medial thigh
What injury causes sensory loss of medial thigh and inability to ADduct thighs?
Obturator
Injury causing obturator injury?
Anterior hip dislocation
Injury caused by anterior hip dislocation?
Obturator injury causing medial thought sensory loss and inability to ADduct thighs
What does femoral nerve innervate?
Leg extensors of quad
- Quads
- Sartorius
- Pectineus
How does femoral nerve injury present?
- Difficulty flexing and extending leg
- Sensory deficit on anterior thigh / medial leg
Which nerve injured:
- Difficulty flexing and extending leg
- Sensory deficit on anterior thigh / medial leg
Femoral
How is femoral nerve injured?
Trauma / pelvic fracture
Nerve injury in pelvic fracture?
Femoral
Another name for common peroneal nerve?
Fibular (lateral bone)
Peroneal innervation?
- Lateral leg muscles: foot eversion
- Dorsal flexion
Tibial innervation?
“TIP”
- Medial muscles: inversion of foot
- Plantar flexion
Cause of foot drop?
Common peroneal injury
Autoimmune disease that can cause foot drop?
MS
What would happen in constantly compression fibule by sleeping on park benches and such?
Fibular nerve injury
Function of superior gluteal nerve?
ABduction of thigh / stabilization of hip
- Trendelenburg sign seen if injured: opposite hip drops when standing on on leg as ipsilateral hip isn’t strong enough to hold steady
When is trendelenburg sign seen?
- Injury to superior gluteal nerve
Where is lesion in hip drop?
Contralateral superior gluteal nerve
Injury in posterior hip dislocation?
Superior gluteal nerve: contralateral hip drop
Inferior gluteal nerve:
Appearance of inferior gluteal nerve injury?
Gluteus maximus innervation: extensor of hip
- Trouble extending hip (pushing it downward), trouble:
1. Jumping
2. Climbing stairs
3. Rising from seated position
Function of glut max?
Hip extension: innervated by inf glut
Injury if having trouble:
- Jumping
- Climbing stairs
- Rising from seated position
Inferior gluteal nerve supplying glut max
Root and innervation of pudendal?
S2 - 4 innervating perineum
How to find pudendal nerve?
Find ischial spine to inject anesthetic in childbirth
Symptoms if compression at L3 - 4?
- Weak knee extension
2. Decrease patellar relfex
Where is lesion if:
- Weak knee extension
- Decrease patellar reflex
L3 - 4
Symptoms if compression at L4 - 5?
- Week dorsiflexion / can’t heel walk
Where is lesion if:
1. Week dorsiflexion / can’t heel walk
L4 - 5
Symptoms if compression at L5 - S1?
- Weak plantar flexion
- Cant toe walk
- Decrease achilles reflex
Where is lesion if:
- Weak plantar flexion
- Cant toe walk
- Decrease achilles reflex
L5 - S1
Nerve and artery along axilla on thorax?
Nerve: long thoracic
Artery: Lateral thoracic artery
Nerve and artery in surgical head of humerus?
Nerve: Axillary
Artery: Posterior circumflex humeral
Nerve and artery in radial groove at midshaft of humerus?
Nerve: radial
Artery: deep brachial
Nerve and artery in cubital fossa?
Nerve: medial
Artery brachial artery
What nerve runs with popliteal artery?
Tibial nerve
Artery with tibial nerve as wraps front of ankle?
Posterior tibial
What are DHP receptors?
“Dihydropyridine receptors”
- Voltage gated Ca channels on surface of myocytes
What are ryanodine receptors?
Ca induced Ca channels on surface of SR in myocyte
What are myofibrils composed of?
Sarcomeres: smallest functional unit of muscle cells
Extent of sarcomere?
Sarcomeres extend from Z line to Z line
“Z is end of sarcomere and the alphabet”
What comes off the Z lines?
Thin Actin molecules projecting in towards the M line
What are the lines coming off the M lines?
Thick Myosin molecules extending out to Z line
What is the H zone?
Stretch of myosin heavy chains not overlapping with actin light chain
What is the I band?
Part of actin light chains not overlapping my myosin heavy chains
When is H zone longest?
Relaxation
What is the A band?
Entire length of myosin heavy chain from end to end
- **Length DOES NOT change with contraction
- The light and heavy chain are simply sliding along each other
Which areas get smaller in contraction?
I band and H zone
Which areas elongate in relaxation?
I band and H zone
How do Z lines appear on EM?
Dark banks
What happens at motor end plate?
Depolarization via Na channels spreading down to T tubules causing DHP-r depolarization allowing Ca to flow in
- Ryanodine receptor on SR changes conformationally allowing Ca release into cytoplasm
Where does Ca bind once release from SR?
Troponin C: cause tropomyosin to move out of myosin binding groove on actin filament
What does myosin do when tropomyosin moves?
Releases ATP it was bound to allowing it to power stroke along actin
What is ATP necessary for?
Detachment of myosin head from actin filament
- This is why you get rigormortis when dead: you can no longer make ATP so can no longer release myosin from actin
Which fibers stain dark and light?
Dark: Type I, sustained contraction
Light: type II, fast twitch, thing “2 fibers = 2x as fast”
What do type I fibers do?
"One Slow Red Ox" Type I Slow Twitch Red Fibers Need Oxidative phosphorylation
Which muscles tend to be slow twitch?
Postural
What type of muscle hypertrophies in weight training?
Type II: white, slow, glycolysis
What does Ca do when enters smooth muscle cell?
- Binds calmodulin instead of RYR or troponin C
- Calmodulin activates Myosin light chain kinase which phosphorylates myosin chains
- Phosphorylated myosin cross bridges along actin
- Myosin light chain phosphatase takes of P causing relaxation
What can cause relaxation in smooth muscle?
- Myosin light chain phosphatase
2. NO from endothelial cells
How does NO cause SM relaxation?
- NO activates guanylyl cyclase increasing cGMP
2. cGMP inhibits myosin light chain kinase
What bones are formed by endochondral ossification?
All the long bones in body
- Cartilage remodeling is first step on which woven and lamellar bone is formed
What is membranous ossification?
- Woven bone directly formed with no cartilage base
* *Occurs in skull and facial bones
What are osteocytes?
- Derived from osteoblasts
- Regulate bone repair and remodeling
Progenitor of Osteoclasts?
Monocytes
What is histologic marker of osteoclasts?
TRAP stain - same stain used in hair cell leukemia
What is TRAP marker for?
Osteoclasts
Impact of estrogen on bone?
- Prevents apoptosis of osteoblasts and osteocytes
- Promotes osteoclast death
* Promotes bone formation
What is achondroplasia? Cause?
- Impaired cartilage proliferation in growth plate
- Impacts longs bones that grow via endochondral ossification
- Caused by activating mutation of FGFR3
What does activation mutation in FGFR3 cause?
Achondroplasia
Presentation of achondroplasia?
- Short extremities with normal head / chest
- Cartilage needed in long bones but not in bones that grow via membranous ossification such as face and chest
What is osteogenesis imperfecta? Cause?
- Congenital defect in bone formation = weak bones
- AD defect in type I collagen
What type of collagen is present in bone?
Type ONE
- Think ONE as in “bONE”
Presentation of osteogenesis imperfecta?
- Bone fractures
- Blue sclera: exposure of choroidal veins
- Hearing loss
* **Type I collagen is found in sclera and ears also
What is the following presentation indicative of:
- Bone fractures
- Blue sclera: exposure of choroidal veins
- Hearing loss
Osteogenica imperfect
What is osteopetrosis?
“Petros” = “rock like”
- Inherited defect in resorptive osteoclast activity = thick, heavy bone that fractures easily
Common cause of osteopetrosis?
Carbonic anhydrase deficiency
- Acid necessary to remove Ca and resorb bone
- Osteoclasts usually use CA to create this
Presentation of osteopetrosis?
- Easy fractures in abnormally thick bone
- Pancytopenia: marrow pushed out by bone
- Vision / hearing impairment: skull compressing CN
- Hydrocephalus: blocks foramen magnum
- RTA: can’t excrete acid / make bicarb in kidney
Treatment of osteopetrosis?
Bone marrow transplant: allows to you make normal monocytes which are progenitors of osteoclasts
Whats is rickets?
- Defective osteoid mineralization due to low Vitamin D `
What is osteomalacia?
Rickets in adults
What is osteoid?
Osteoblasts make osteoid which must be mineralized with Ca and P to make final bone
Rickets presentation?
- Pigeon breast
- Bow legs
- Frontal bossing: osteoid deposition in skull
- Rachitic rosary: osteoid deposition at CV junction
Lab values in osteomalacia?
- Low Ca
- Low P
- Increased PTH
- Increased Alk phos
What does alk phos do?
Released by osteoblasts to create alkaline environment that is necessary for Ca deposition
What is osteoporosis?
- Loss of trabecular bone mass = porous bone that easily fractures
What is risk of osteoporosis based on?
- Peak bone mass
2. Rate of decline after peak
What determines peak bone mass?
- Diet
- Exercise
- Vitamin D receptor you inherit
Osteoporosis presentation?
- Pain in fractures in weight bearing areas
How is bone density measured?
Dexa scan
Serum levels in osteoporosis?
Everything is normal
Osteoporosis therapy?
- Exercise
- Vitamin D / Ca
- Bisphosphonates
How do bisphosphonates work?
- Attaches to bone and osteoclasts eat it leading to their death
What is paget’s disease of bone?
- Imbalance between osteoclasts and blasts
- Normally PTH signals blasts which activate clasts
- In paget’s, this signalling goes awry = increase resorb
- Blasts try to catch up but lay down weak bone
- Result is thick sclerotic bone that easily fractures
Whaten is mosaic pattern of lamellar bone seen?
Paget’s
Paget’s presentation?
- Increasing hat size
- Bone pain
- Hearing loss
- Lion faces
- Elevated alk phos
What is following indicative of:
- Increasing hat size
- Bone pain
- Hearing loss
- Lion faces
- Elevated alk phos
Paget’s
Paget’s treatment?
- Calcitonin
2. Bisphosphonates
Paget’s complications?
- High output cardiac failure
2. Osteosarcoma: malignant blast tumor
How does osteomyelitis occur?
Hematogenous bacterial spread
Kids: seeds metaphysis
Adults: seeds epiphysis
What are the epiphysis, metaphysis, and diaphysis?
From the “EMD” of the bone
- different parts of bone from its end moving down bone
What is avascular necrosis?
- Ischemic, aseptic necrosis of bone / marrow
- Leads to Osteoarthritis and fracture
Causes of avascular necrosis?
- Trauma / fracture
- Steroids
- Sickle cell: dactylitis
- Caisson disease: gas emboli
What is a osteoma?
- Benign bone tumor
- Normally on surface of facial bones
- Seen in Gardner syndrome
What is Gardner syndrome?
- Osteoma
- Familial adenomatous polyposis
- Fibromatosis of retroperitoneum
What is osteoid osteoma?
- Benign tumor of osteoblasts with rim of reactive bone
- Seen in
Tumor with rim of reactive bone in long bone of 20 yo?
Osteoid osteoma
What tumor has bone pain that resolves with aspirin?
Osteoid osteoma
What tumor is bony mass with radiolucent core?
Osteoid osteoma
Characteristics of osteoblastoma?
- Benign tumor of osteoblasts
- > 2cm
- Found in vertebrae
- Bone pain that does not respond to ASA
What is the following:
- Benign tumor of osteoblasts
- > 2cm
- Found in vertebrae
- Bone pain that does not respond to ASA
Osteoblastoma
What is osteochondroma?
- Benign tumor of bone with cartilage cap
- “chondro” = cartilage
- Arises as lateral projection of growth plate
What is the following:
- Benign tumor of bone with cartilage cap
- “chondro” = cartilage
- Arises as lateral projection of growth plate
Osteochondroma
What is chondrosarcoma?
- Malignant transformation of cartilage camp on osteochondroma
What is osteosarcoma?
- Malignant osteoblastic tumor
- Peak incidence in teenagers
- In metaphysis of long bone: distal femur, proximal tibia
Osteosarcoma risks?
- Familial retinoblastoma
- Pagets
- Radiation
What is the following:
- Malignant osteoblastic tumor
- Peak incidence in teenagers
Osteosarcoma
What is familial retinoblastoma?
- Bilateral retinoblastoma
2. Osteosarcoma
Presentation of osteosarcoma?
- Pathologic fracture
- Bone pain with swelling
- Drags periosteum off bone: layer of connective tissue “Codman’s angle”
Tumor in metaphysis of long bone?
Osteosarcoma
Which tumor pulls periosteum off bone: “Codman’s angel”?
Osteosarcoma
“Pleomorphic cells producing osteoid?”
Osteosarcoma
What is giant cell tumor?
- Tumor of giant / stromal cells in young adults
- Arises in epiphysis
- Locally aggressive with recurrence
“Soap bubble sign”
Only tumor in epiphysis?
Giant cell tumor
“Soap bubble sign?”
Giant cell tumor
What is ewing sarcoma?
- Malignant growth of poorly differentiated cells of neuroectodermal origin
- Male kids
- Diaphysis of long bones
- Onion skin on Xray
What is following:
- Malignant growth of poorly differentiated cells of neuroectodermal origin
- Male kids
- Diaphysis of long bones
- Onion skin on Xray
Ewings
Translocation in ewings?
11:22
What is 11:22 translocation seen in?
Ewing’s sarcoma: 33 is his jersey number
What is chondroma?
- Benign tumor of cartilage
- Medulla of hands and feet
Location of benign and malignant cartilage tumors?
Malignant: Pelvis / central skeleton
Benign: small bones of hands and feet
When are punched out osteolytic lesions seen?
Metastasis to bones
Presentation of prostate in bones?
Osteoblastic lesions
Type of cartilage at joints?
Type II: think, this is where TWO bones come together
What is synovium?
Lining that surrounds a joint making a capsule
- Secretes fluid of Hyaluronic acid to lubricate joint
What is degenerative joint disease?
- Degeneration of articular cartilage from wear and tear
- Seen with age, obesity, and trauma
- *Joint stiffness in morning that worsens throughout day
When is stiffness worsening through day seen?
Degenerative joint disease
What hand joins is degenerative joint disease in?
DIP
PIP
What is eburnation?
- Rubbing / polishing of bone seen in degenerative joint disease from lack of cartilage
- Bone rubbing against bone will the to reactive osteocytes
When are osteocytes seen in DIP and PIP?
Degenerative joint disease
What are heberden and bouchard nodes?
- Osteocytes seen in DIP and PIP in degenerative joint disease
Genetic association of RA?
HLA-DR4
What is HLA DR4 implicated in?
RA
Hallmark of RA?
Synovitis leading for formation of pannus: inflamed granulation tissue
When is this seen:
Synovitis leading for formation of pannus
RA
Pannus = inflamed granulation tissue
What is occurring in the synovitis in RA?
- Myofibroblasts in granulation tissue of pannus cause:
1. Ankylosis: fusion of joint
2. Movement of joint in different directions
3. Destruction of articular cartilage
What is ankylosis?
Fusing of joint that can be seen in RA from myofibroblast contraction
When is morning stiffness improving during day seen?
RA
- Compare it to inflammation of your throat when you wake up in morning it is worse then improves during day
Joints in RA?`
Symmetrical involvement of:
- PIP
- Wrists
- Elbows
- Ankles
- Knees
* **Sparing DIP
When is symmetric` joint involvement sparing DIP seen?
RA
Joint disease with systemic signs?
RA
What are rheumatoid nodules?
- Central area of necrosis surrounded by epithelioid histiocytes
Associated features of RA?
- Vasculitis
- Rheumatoid nodules
- Baker Cysts: seen in leg pit
Lab findings in RA?
- IgM antibody against FC portion of IgG
When is the following seen:
- IgM antibody against FC portion of IgG
RA
Sequelae of RA?
- Anemia of chronic disease
2. Secondary amyloidosis: deposition of AA
What is deposited in secondary amyloidosis?
- SAA made in liver converted to AA which is deposited in tissues
Characteristics of seronegative spondyloarthropathies?
- Lack rheumatoid factor
- Axial skeleton
- HLA B27 association
Joint involvement in ankylosing spondyloarthritis?
- Spine
2. SI joint
Presentation of ankylosing spondyloarthritis?
Young male with:
- Low back pain
- Fusion of vertebrae: bamboo spine
- Uveitis
- Aortitis
When is bamboo spine seen?
Ankylosing spondylitis
Characteristics of psoriatic arthritis?
- Psoriasis
- Axial and distal skeleton
- “Sausage fingers of DIP”
When are sausage fingers seen?
Psoriatic arthritis
Presentation of infectious arthritis?
N. gonorrhoeae or S aureus infx causing:
- Warm, red joint with limited motion
- Fever
- Increased WBC
- Increased ESR
* **Single joint, usually knee
What is happening in gout?
Monosodium urate deposition in tissues due to increased uric acid
How do we arrive at uric acid?
- Purine degradation products AMP / GMP taken into enterocyte
- GMP broken to guanine, AMP to HYPOxanthine
- Both products broken to xanthine
- Xanthine oxidase converted to uric acid
- Uric acid filtered by kidney unless too much
What is xanthine oxidase?
- In breakdown of purines, converts xanthine to uric acid
Causes of secondary gout?
- Leukemia and myeloproliferative: high cell turnover - increased purines
- Lesch nyhan
- Kidney failure
What is lesch nyhan?
HGPRT deficiency in purine salvage pathway leading to increased uric acid causing:
- Gout
- Mental retardation
- Self mutilation
What is HGPRT?
Salvages Hypoxanthine and guanine from purine degradation pathway
- Leads to decreased uric acid
What is the following:
- Gout
- Mental retardation
- Self mutilation
Lesch Nyhan
What causes inflammation in acute gout?
MSU crystals in joints are activating neuts
What is podagra?
- Painful arthritis of great toe seen in gout
Why does booze cause gout?
Byproducts of alcohol compete with uric acid for excretion
What are tophi?
- Uric acid crystals in tissues and joints that is hallmark of chronic gout
- Which chalky deposits on histo
Lab in gout?
- Needled shaped crystals with NEGATIVE birefringence under polarized light
- When flat = yellow “When lay low, yellow”
What does negative birefringence mean?
- When flat = yellow “When lay low, yellow”
Seen in gout UA crystals
What is pseudogout?
- Ca pyrophosphate crystals in joints
- Rhomboid crystals with weak positive birefringence
What is following:
- Needled shaped crystals with NEGATIVE birefringence under polarized light
Gout
What is following:
- Rhomboid crystals with weak positive birefringence
Pseudogout
- Think pseu, positive, pyrophosphate, all begin with Ps
What is dermatomyositis?
- Inflammatory disease of skin and muscle often associated with gastric carcinoma
Presentation of dermatomyositis?
- Proximal, bilateral muscle weakness: cant raise arms of climb stairs
- Rash of upper lids
- Malar rash
- Red papules on knees, knucles, elbows
What is following:
- Proximal, bilateral muscle weakness: cant raise arms of climb stairs
- Rash of upper lids
- Malar rash
- Red papules on knees, knucles, elbows
Dermatomyositis
Labs in dermatomyositis?
- Increased creatine kinase
- Positive ANA
- Anti JO-1 Ig
- Perimysial inflammation with perifascicular atrophy
When is DSDNA Ig seen?
Lupus
When is following seen:
Perimysial inflammation with perifascicular atrophy
Dermatomyositis
What is perimysium? When is it inflamed?
Connective tissue surrounding muscle fascicles: inflamed in dermatomyositis
***Think, the perimysium is on outside of fiber close to skin so it must be inflamed in dermatomyositis
What is endomysium? When is it inflamed?
Connective tissue between fibers
- Inflamed in polymyositis
What is polymyositis?
- Inflammatory condition of skeletal endomysium
- No skin involvement
- CD8 and necrotic fibers seen
What is X linked muscular dystrophy? Caused?
- Degenerative muscles wasting in which muscle is replaced by adipose tissue
- Caused by DELETIONS of dystrophin
What is following:
- Degenerative muscles wasting in which muscle is replaced by adipose tissue
Muscular dystrophy
What is dystrophin?
- Largest gene in humans:
- DELETED in DMD
- Anchors muscle cytoskeleton to ECM
DMD presentation?
- Proximal muscle weakness at 1 yo
- Calf pseudohypertrophy
- Elevated CK
Death in DMD?
Cardiac or respiratory failure once they become involved
What is becker muscular dystrophy?
- Mutations in dystrophin
- Similar to DMD but milder as DMD is deletion
Transmission at NMF?
- Ca channel opening allows for AcH release
- AcH binds nicotinic receptors on endplate
What happens in myasthenia gravis?
- Ig binds nicotinic receptor at NMJ endplate
- Receptor is not destroyed, Ig just creates competition
- With rapid firing, not enough Ach Can be released to fire muscle
- *Classically seen in eyes = ptosis and double vision
When is muscle weakness worse with use and better with rest seen?
MG
Association of MG?
- Thymoma - improved if removed
2. Thymic hyperplasia
What happens in eaton lambert?
Ig vs presynaptic Ca channel
- Seen in small cell carcinoma of lung
- Proximal muscles involved sparing eyes
- Improves with use
Muscles in MG and eatons?
MG: eye with ptosis is first
Eaton: eye spared, proximal muscles infected
MG eaton improve or worsen with use?
MG: worsen
Eaton: improve
When is lipoblast seen?
Liposarcoma
When is cardiac rhabdomyoma seen?
Tuberous sclerosis
Which tumor is desmin +?
Rhabdomyosarcoma
- Often seen in vagina of young girl
What does basement membrane separate?
Epidermis from underlying dermis
Layers and functions of epidermis?
Moving up from basement:
- Basalis: stem cell layer
- Spinosum: connected by desmosomes
- Granulosus: granules in cells
- S. corneum: keratin in cells
What are desmosomes?
Connect the keratinocytes in S. basalis
What is in dermis?
- Connective tissues
- Blood vessels moving up to dermis
- Hair cells
- Sebaceous glands (sweat)
Are there blood vessels in epidermis?
No
Another name for eczema?
“Atopic dermatitis”
What is atopic dermatitis?
“Eczema”
- Itchy, red, oozing rashing with vesicles and edema
- Face and flexor surfaces
- Type I HSR associated with asthma and rhinitis
What is following:
- Itchy, red, oozing rashing with vesicles and edema on face and flexor surfaces
Atopic or contact
Atopic dermatitis associations?
Type I HSR associated with:
- Asthma
- Allergies
What is contact dermatitis?
- Same appearance of atopic dermatitis but due to exposure to allergen: Itchy, red, oozing rashing with vesicles and edema
- **Not a type I HSR: could be IV
What type of HSR are nickel and IVY?
Type IV
Drug causing contact dermatitis?
Penicillin
Lesions seen in acne vulgaris?
- Comedones: white and black heads
- Nodules
- Pustules: pimples
Cause and pathology of acne?
- Chronic inflammation of hair follicles and sebaceous glands
- Hormone induced increased sebum and excess keratin production in epithelial cells of follicle = blockage: comedones
- Propionibacterium acnes = inflammation
How does P. Acnes cause acne?
- Keratin blocks follicle and excess sebum fills it = comedone
- P. Acnes infects and releases lipases breaking down sebum releasing inflammatory FFAs = inflammation = pimple
Acne treatment?
- Benzoyl peroxide: antibiotic
2. Isotretinoin: vitamin a derivatives block keratin production
What is psoriasis?
- Well circumscribed salmon plaques with silver scale
- Usually on extensors and scalp
- Pitting of nails can be seen
- Hyperplasia and epidermal thickening: acanthosis
- Parakeratosis
What is following:
- Well circumscribed salmon plaques with silver scale
Psoriasis
Cause of psoriasis?
- Excessive keratinocyte proliferation
- Possibly autoimmune and associated with HLA c
- Can arise in areas of trauma
Genetics of psoriasis?
HLA C: say “"”CCCCCC-riassis”
What is hyperplasia with increased thickening of epidermis seen in?
Acanthosis: characteristic of pWsoriais
When are parakeratosis and acanthosis seen?
Psoriasis
When / what are munro microabscesses?
- Seen in psoriasis
- Neuts deposited in excess parakeratosis
When is elongation of dermal papillae seen?
Psoriasis: allows vessels to protrude into epidermal areas where not normally found which is why plaques bleed when come off
What is auspitz sign?
- Bleeding when plaques picked off in psoriais
Psoriasis Rx?
- Steroids
- UVA light with psoralen: damages keratinocytes - “PUVA”
- Immune madulators
What is lichen planus?
- Pruritic, polygonal, planar, purple patches
- Often have white lines on surface: Wickham striae
- Can be seen in mouth
What is inflammation of dermal epidermal junction with sawtooth appearance?
Lichen planus
Histo of lichen planus?
Inflammation of dermal epidermal junction with sawtooth appearance
Association of lichen planus?
Chronic HCV
How does a blister arise?
- Separation of layers of skin = bubble
- Can happen between various layers
What is pemphigus vulgaris?
- Autoimmune destruction of desmosomes: connect keratinocytes in spinosum
- IgG vs. desmoglein
- Fishnet on IF of IgG around keratinocytes
- Blister is between intact basal and rest of epidermis
- Thin epidermal wall on top of blister that easily ruptures
What is blister on top of intact basal layer?
Pemphigus vulgaris: IgG against desmoglein of desmosomes
What is acantholysis?
Separation of keratinocytes
What does hemidesmosome do?
Attach basal cell to basement layer: attacked in bullous pemphigoid
Where does pemphigus vulgaris present?
Skin AND oral mucosa
What is bullous pemphigoid?
- Autoimmune destruction of hemidesmosomes by IgG against basement membrane
- Subepidermal blisters with oral sparing
Which blister is on mouth?
Pemphigus vulgaris: think it would be “vulgar” looking to have blister on mouth
Which Blister is thicker?
Bullous pemphigoid: think, it is thicker because the entire epidermal layer is on top and BM is on bottom and “Bullous” starts with B
What is dermatitis herpetiformis?
- IgA deposition at tips of dermal papillae
- Itchy grouping of bullae and vesicles
- Seen in celiacs
What is erythema multiforme?
- HSR withtargetoid rash and bullae
- Often seen in HSV
What is SJS?
- Erythema multiforme with oral involvement
2. Fever
What is TEN?
“Toxic epidermal necrolysis” severe SJS
- Sloughing of skin
- From drug rxn
What causes impetigo?
Staph or pyogenes
What causes cellulitis?
Staph or pyogenes
What can cellulitis progress to?
Necrotizing fasciitis
What is necrotizing fasciitis?
- Necrosis of sub q tissue from infx
2. CO2 production = crepitus
Layer separated in scalded skin?
S. Granulosus
Where does TEN occur?
Dermal / epidermal junction
What is verruca?
AKA wart
What is molluscum contagiosum?
Firm, pink umbilicated papule from POX virus
What is seborrheic keratosis?
Benign proliferation of squamous cells common in elderly
- Raised grey plaque with stuck on appearance
What are circular spaces with abundant pink keratin / pseudo cysts indicative of on histo?
Seborrheic keratosis
What is Leser trelat sign?
- Sudden onset of multiple Seborrheic keratosis
2. Usually with GI carcinoma
When is epidermal hyperplasia with darkening of skin seen?
- Insulin resistance
2. Malignancy
What is xeroderma pigmentosum? What does it put you at risk for?
AR defect in nucleotide excision repair enzymes
- At risk for BCC
What does UVB do to skin?
- Forms pyrimidine dimers that need to be repaired by nucleotide excision repair
- Enzyme is deficient in xeroderma pigmentosum putting you at risk for BCC
What is following:
- Elevated nodule, central necrosis, dilated vessels surrounding
BCC
Which skin cancer shows peripheral palisading?
BCC
BCC prognosis?
Rarely metastasizes
Risks for SCC?
- Immunosuppression
- Arsenic
- Chronic inflammation: scar from burn / draining sinus tract
- Actinic keratosis
Skin cancer often appearing on scars?
SCC
Which cancers present on upper and lower lip?
“Bull shit”
Upper: BCC
Lower: SCC
What is actinic keratosis?
- SCC precursor
- HYPERkeratotic scaly plaque
What is a hyperkeratotic scaly plaque?
Actinic keratosis - risk for SCC
What is keratoacanthoma?
- Well differentiated SCC that rapidly progresses, then rapidly regresses
- Cup shaped tumor with keratin debris in center
What is following:
- Well differentiated SCC that rapidly progresses, then rapidly regresses
- Cup shaped tumor with keratin debris in center
Keratoacanthoma
How do melanocytes work? Where are they found?
- Found in basal layer of epidermis
- Take tyrosine to make melanin in melanosomes
- Melanin is passed to keratinocytes causing pigmentation
Origin of melanocytes?
Neural crest in nature - S100 +
What is vitiligo?
Localized autoimmune destruction of melanocytes = loss of pigmentation
What is local autoimmune destruction of melanocytes?
Vitiligo
What is albinism?
- Congenital lack of pigmentation from defect in tyrosinase enzymes impairing melanin production
- Can only involved eyes or eyes and skin
Why do freckles darken relative to neighboring cells?
Increased numbers of melanosomes
What is melasma?
Mask like hyperpigmentation of cheeks associated with OCPs and pregnancy
What a nevus?
“mole”
- Benign neoplasm of melanocytes
Is hair growing from mole a good sign?
Yes, this is not seen in melanoma as they would destroy the follicles
Are nevis precursors to melanoma?
They can be if they develop dysplasia
ABCs of melanoma?
Asymmetry
Border irregularity
Color changes throughout
Diameter > 6 mm
Key feature for risk of metastasis in melanoma?
Depth of invasion
4 Types of melanoma?
- Lentigo maligna
- Superficial spreading
- 4.
What is lentigo maligna melanoma?
Lentiginous proliferation (along dermal line) of melanocytes - Good prognosis as not much depth of invasion
What is the following:
Melanocyte proliferation along dermal line
Lentigo melanoma
What is superficial spreading melanoma?
Dominant early radially phase:
- Good prognosis as not going deep
Which melanoma has dominant early radial phase?
Superficial spreading
What is nodular melanoma
- Early vertical phase: poor prognosis
- Pushes skin up as it goes deep which is why it is called nodular
Which melanoma has early vertical phase?
Nodular
What is acral lentiginous melanoma?
- Palms and soles of dark skinned folks
- Not relation to UV light
What is melanoma of palms and soles?
Acral lentiginous
Risk for having a child with achondroplasia?
Advanced paternal age
What is decrease in trabecular mass despite normal mineralization and lab values?
Osteoporosis
Diagnostics of osteoporosis?
Osteoporotic: > 2.5 SDs from mean
Osteopenic: 1 SD from mean
When are chalk stick fractures in long bones seen?
Pagets
How will paget’s of bone kill you?
- AV shunts through bone: high output HF
2. Osteogenic sarcoma
Increasing hat size and elevated alk phos?
Pagets
2 bone diseases with normal labs?
- Osteoporosis
2. Osteopetrosis
Labs in rickets?
- Low Ca
- Low P
- Increased Alk phos
- Increased PTH
Bone tumor with homer wright rosettes?
Ewing sarcoma
Characteristics of type III HSR?
Ig / complex mediation
When is DIP spared?
RA
What does probenecid do?
Cause increased uric acid excretion
Where does pseudogout present?
Usually larger joints
Presentation of sjogren’s?
- Xerophthalmia: Dry eyes / “sand in eyes”
- Xerostomia: dry mouth / dysphagia as makes it hard to swallow
- Enlarged parotids
- RA
* **caused by exocrine destruction of salivary and lacrimal glands
What is the following?
- Xerophthalmia
- Xerostomia
- Enlarged parotids
- RA
Sjogren
Antibodies in sjogren’s?
- Anit RNP
- Anti Ro / SSA
- Anti La / SSB
When is following seen:
- Anit RNP
- Anti Ro / SSA
- Anti La / SSB
Sjogrens
Diagnosis in teenager with red hot joint?
Gonorrhea
Bone disease with HLA B27?
Seronegative spondalropathies
Pencil / cup deformity?
Psoriatic arthritis
Joint disease caused by IBD?
Sacroiliitis
What does lupus cause in heart?
- Libman sachs endocarditis
2. Pericarditis
What is chest pain relieved by leaning forward and worse on lying down and deep breaths?
Pericarditis
SLE on kidney?
- Diffuse proliferative glomerulonephritis
- Membranous glomerulonephritis
* *Type III HSRs
4 serum markers for lupus?
- Anti DSDNA
- Antismith
- ANA
- Antihistone: drug induced lupus
Drugs causing drug induced lupus?
- Hydralazine
- Procainamide
- Isoniazid
Characteristics of antiphospholipid syndrome?
- 1st semester clot or abortion
- False positive VDRL
- Falsely prolonged PTT
- Lupus anticoag / anticardiolipin / Anti B2
What is following:
- ANA
- anti-U1-RNP
Mixed connective tissue disease
Schaumann and asteroid bodies?
Sarcoid
Sarcoid presentation?
- Restrictive lung disease
- Bell palsy
- Erythema nodosum
- Uveoparotitis
Labs in sarcoid?
- Increased ACE
- Increased Ca: macs in granulomas activate vitamin D
- Increased CD4:8 ratio
What is polymyalgia rheumatic?
- Pain and stiffness in hips and shoulders
Women > 50 with muscle pain and no weakness?
Polymyalgia rheumatica
Association of Polymyalgia rheumatica?
Giant cell arteritis
What is polymyositis?
- Progressive, symmetric, proximal muscle weakness
What is myositis ossificans?
Ca deposits in muscles
What is scleroderma?
- Widespread collagen deposition in body = fibrosis
- Tight, puffy skin
When is SCL 70 seen?
Diffuses scleroderma
Lab in Diffuses scleroderma?
SCL 70
What is CREST? Lab
*Anticentromere Ig Calcinosis Raynaud's Esophageal dysmotility Sclerodactyly Telangiectasia
When is anticentromere Ig seen?
CREST
Cause of Raynaud’s?
Excess Alpha receptors on vessels of hands = constriction