Musculoskeletal Flashcards
What nerve is affected by this injury?
Fibular neck fracture
Trauma to the lateral leg can cause common peroneal damage. Sensory deficit would be anterolateral leg & dorsum of foot.
TIPPED:
Tibial inverts & plantar flexes, Peroneal everts & dorsiflexes
What are the muscles of the thenar & hypothenar eminences?
Both are OAF Thenar: Opponens pollicis Adbuctor pollicis brevis/Adductor pollicis Flexor policis brevis
Hypothenar:
Opponens digiti minimi
Abductor digiti minimi brevis
Flexor digiti minimi brevis
What nerve is affected by this injury?
Knee trauma
Tibial nerve can be injured in knee trauma. Sensory deficit would be the sole of the foot. The most important thing to assess with knee dislocation or trauma is the popliteal artery. It is easily injured & can lead to amputation.
TIPPED:
Tibial inverts & plantar flexes
What nerves could be affected by this injury?
Posterior hip dislocation
Superior gluteal –> Trendelenberg sign
Inferior gluteal –> Can’t rise from a seat or climb stairs.
What nerve is affected by this injury?
Anterior hip dislocation
Obturator nerve
Motor: Thigh adduction deficit
Sensory: Medial thigh deficit
What nerve is affected by this injury?
Pelvic fracture
Femoral n. is common
Motor defcicit: Thigh flexion & leg extension
Sensory deficit: Anterior thigh & medial leg
What are the types of fibers in skeletal muscle?
Type I & Type II
“1 slow red ox”
Type 1 are slow twitch
Red due to myoglobin & mitochondria
Oxidative phosphorylation
How does NO cause smooth muscle relaxation?
NO –> ^Guanylate cyclase activity –> ^cGMP –> myosin light chain phosphatase (MLCP) –> relaxation
What are the two types of bone formation & where do they occur?
Endochondral ossification:
Bones of axial & appendicular skeleton
Cartilaginous model made first by chondrocytes. Then osteoblasts/clasts –> woven bone –> lamellar bone
Membranous ossification:
Skullcap & facial bones
Woven bone –> lamellar bone (no cartilage)
How does estrogen affect bone metabolism?
Inhibits apoptosis in osteoblasts
Induces apoptosis in osteoclasts
What causes achondroplasia?
Autosomal dominant activating mutation in FGFR3 –> inhibits chondrocyte proliferation –> impaired endochondral ossification
*** >80% of mutations are spontaneous
What is seen in osteoporosis?
Trabecular (spongy) bone loses mass & interconnections
Normal lab values
Abnormal DEXA scan
Pathologic fractures
What type of fractures are seen in Osteoporosis?
Femoral neck fracture
Vertebral crush fracture
Distal radius fracture
What are the types of osteoporosis?
Type I = postmenopausal
Type II = senile (men & women >70y)
What causes osteopetrosis?
What is seen?
Mutations impair osteoclasts’ ability to form acidic environment required for resorption. Common cause is mutated carbonic anhydrase type 2.
Symptoms:
Pancytopenia
Extramedullary hematopoiesis
Dense bones on X-ray with no medulla
Cranial nerve impingement –> focal deficits
Type II renal tubular acidosis (if carbonic anhydrase def.)
What is seen histologically with osteomalacia/rickets?
Vit. D deficiency –> impaired mineralization of osteoid
What is seen with osteomalacia & rickets?
^PTH, ^Alk Phos, decreased Ca2+ & Phosphate
Osteomalacia - pathologic fractures
Rickets: Pigeon-breast deformity Rachitic rosary Frontal bossing Bowing of legs (if ambulatory)
What is seen with Osteitis fibrosa cystica?
^Alkaline phosphatase (the only abnormal lab) Hearing loss Lion face Mosaic/woven pattern of bone Fractures ^ Hat size
Increased risk for osteosarcoma & high output CHF.
What is seen in McCune-Albright Syndrome?
Polyostotic fibrous dysplasia (bone replaced with fibrous tissue)
Precocious puberty
Cafe-au-lait spots
Where on the bone are the various primary cancers typically found?
Giant cell tumor (osteoclastoma) - Epiphysis
Osteosarcoma & Osteochondroma - Metaphysis
Ewing’s & Chondrosarcoma - Diaphysis
Chondrosarcoma is typically intramedullary.
How does a giant cell tumor (osteoclastoma) present?
Soap bubble appearance on x-ray
Located at the epiphysis (knee)
Spindle cells with multinucleate giant cells
20-40y
How does an Osteochondroma present?
Mature bone with cartilaginous cap (looks like little bone)
Found on metaphysis
Males under 25y
^Risk of chondrosarcoma
What risk factors are associated with osteosarcoma?
Familial retinoblastoma
Paget’s disease of the bone
Radiation
Bone infarcts
What is seen with osteosarcoma?
Codman’s triangle (elevation of periosteum)
Sunburst x-ray
Found at metaphysis of long bones (knee)
Male teenagers
What mutation is seen in Ewing’s Sarcoma?
t(11;22)
11+22 = 33 (Patrick Ewing’s number)
What is seen with Ewing’s sarcoma?
Seen in males <15y
Anaplastic small blue cell tumor (from neuroectoderm)
Onion skin appearance
Aggressive with early mets but responds well to chemo.
What is seen with chondrosarcoma?
Found in axial or proximal skeleton
Men 30-60y
Mass within the medullary cavity (diaphysis)
With bone tumors, what does the response to aspirin mean?
Responds to aspirin —> osteoid osteoma
Does not respond –> osteoblastoma
What metastases are osteolytic?
Osteoblastic?
Osteoblastic = Prostate cancer
Osteolytic = BLT w/ Ketchup & Mustard
Breast (lytic/blastic) Lung Thyroid Kidney Multiple myeloma
What joint findings are seen in osteoarthritis?
Subchondral cysts
Osteophytes (bone spurs)
Eburnation (polished bone)
Heberden’s nodes (DIP); Bouchard’s nodes (PIP)
What intra-articular findings are seen in RA?
Pannus formation (granulation tissue) Rheumatoid nodules Ulnar deviation Fusion Baker's cyst (in popliteal fossa)
What Ig’s are seen in RA?
Anti-cyclic citrullinated peptide Ab Rheumatoid factor (IgM against Fc portion of IgG)
What is seen in Sjögren’s syndrome?
Dry eyes (Xerophthalmia) Dry mouth (Xerostomia) Arthritis Parotid enlargement (if occurring quickly or asymmetrically --> B cell lymphoma!!)
What Ab’s are present in Sjögren’s syndrome?
RoLa = AB
Anti-Ro = SS-A Anti-La = SS-B
What are risk factors for gout?
Thiazide diuretics von Gierke's disease ^ cell turnover (malignancy) Lesch-Nyhan Renal insufficiency
Vast majority is primary goud (idiopathic)
What type of crystals might be seen on a joint tap?
Needle shaped & negatively birefringent –> gout
(Monosodium urate)
Rhomboid & positively birefringent –> pseudogout
(Calcium pyrophosphate)
What is the treatment for gout?
Acute = NSAID's; Steroids Chronic = Xanthine oxidase inhibitors (Allopurinol, Febuxostat)
What are the common bugs in septic arthritis?
S. aureus
Streptococcus
Gonorrhea
What are the risk factors for Osteonecrosis (avascular necrosis)?
Trauma High-dose corticosteroids Alcoholism Sickle cell anemia SLE
*Seen most commonly in the femoral head
What are the seronegative spondylarthropathies?
Who are they seen in?
PAIR: Psoriatic arthritis Ankylosing spondylitis Inflammatory bowel disease Reiter's syndrome (reactive arthritis)
They are more common in males & those with HLA-B27
What is seen with psoriatic arthritis?
Psoriasis
Asymmetric joint pain
Dactylitis –> “pencil in cup” deformity on x-ray
What is seen with ankylosing spondylitis?
Chronic inflammation of spine & sacroiliac joints Ankylosis = fusion of spine "bamboo spine" on x-ray Uveitis Aortitis --> aortic regurgitation
What is seen in Reiter’s syndrome?
Reactive arthritis triad:
Conjunctivitis
Urethritis
Arthritis
“Can’t see, can’t pee, can’t climb a tree”
What population gets SLE?
Females between 14-45
Most common & most severe in black women
What are the features of SLE?
I’M DAMN SHARP
Immunoglobulins (autoAb's) Malar rash Discoid rash Antinuclear Ab Mucositis (oropharyngeal ulcers) Neurologic psychosis Serositis (pleuritis, pericarditis) Hematologic disorders Arthritis Renal disorders (DPGN = most common cause of death) Photosensitivity
Also Libman-Sacks endocarditis, Raynaud’s, hilar LAD, fever, fatigue, weight loss.
What cardiac manifestations can be seen with SLE?
Libman-Sacks endocarditis:
Sterile wart-like vegetations on both sides of the valve
Myocarditis, pericarditis
What hematologic manifestations are seen in SLE?
Lupus anticoagulant –> hypercoagulable but ^PTT
Any combination of anemia, thrombocytopenia, neutropenia
Immunoglobulins against everything ever
What is seen with antiphospholipid antibody syndrome?
Lupus anticoagulant:
- -Paradoxical ^PTT
- -DVT’s
- -Bud-Chiari
- -Placental thrombosis (recurrent pregnancy loss)
- -Stroke
Anticardiolipin –> false-positive VDRL
What diagnostic antibodies are seen in SLE?
Antinuclear Ab’s (ANA) - sensitive, not specific for SLE
Anti-dsDNA - Specific; poor prognosis
Anti-Smith - Very specific
Antihistone - Drug induced lupus
What drugs are associated with drug-induced lupus?
HIP:
Hydralazine
INH
Procainamide
What is seen in diffuse systemic scleroderma?
Excessive fibrosis & collagen deposition of any organ (pulmonary, renal, CV, GI)
Esophageal dysmotility
Tight skin, especially hands & face
Anti-DNA Topoisomerase I Ab (Anti-Scl-70)
ANA’s
What is seen in CREST syndrome?
Calcinosis cutis Raynaud's Esophageal dysmotility Sclerodactyly Telangiectasia
Anti-centromere Ab’s
What is seen with sarcoidosis?
HULA BABIES Hypercalcemia (epithelioid macs express 1-alpha-hydroxylase) Uveitis Lymphadenopathy (bilateral hilar) ^ACE levels Black females Asteroid bodies Bell's palsy Interstitial lung fibrosis Erythema nodosum Schaumann bodies
What is seen histologically in polymyositis & dermatomyositis?
Polymyositis - Endomysial inflammation with CD8+ infiltration & necrotic muscle fibers.
Dermatomyositis - Perimysial inflammation with CD4+ infiltration & perimysial atrophy.
**The one that has skin manifestations is closer to the skin (perimysial)
What is seen clinically with dermatomyositis?
Proximal muscle weakness (like polymyositis)
Malar rash
Gottron’s papules (knuckles, elbows, knees)
Heliotrope rash (upper eyelids)
^risk of occult (often gastric) malignancy
What labs are abnormal in dermatomyositis/polymyositis?
^CK
ANA’s
Anti-Jo-1 Ab’s
Tx = steroids
What is seen with Mysthenia gravis?
Ptosis, diplopia Weakness Worsens with muscle use (ACh gets depleted) AChE inhibitors reverse symptoms Thymic hyperplasia/Thymoma
What is seen with LEMS?
Proximal muscle weakness & autonomic symptoms
Improves with muscle use
Underlying small cell lung carcinoma
AChE inhibitors have no effect
What causes MG and LEMS?
Myasthenia Gravis - AutoAb’s against postsynaptic ACh receptor compete with ACh for it.
LEMS - AutoAb’s against presynaptic Ca2+ channel decrease ACh release
What causes myositis ossificans?
Muscular trauma –> metaplasia of muscle to bone at site
Usually seen in arm or leg muscles. Can present as a mass following trauma or finding on radiography.
Define these terms: Hyperkeratosis Parakeratosis Orthokeratosis Acanthosis Acantholysis
Hyperkeratosis - ^stratum corneum (consists of para & ortho)
Parakeratosis - ^stratum corneum with retention of nuclei
Orthokeratosis - ^stratum corneum with no nuclei
Acanthosis - ^stratum spinosum (epidermal hyperplasia)
Acantholysis - separation of erpidermal cells
What causes melasma?
Melasma = blotchy hyperpigmentation of the face from pregnancy or OCP use
What causes vitiligo?
Autoimmune destruction of melanocytes
What are the two types of nevi?
Junctional - found in children; flat
Intradermal - found in adults; raised
What are the medical terms for the following? Wart Freckle Mole Hive
Wart - Verruca
Freckle - Ephelis
Mole - Melanocytic nevus
Hive - Urticaria (presents as a wheal)
What type of hypersensitivity is eczema & contact dermatitis?
Atopic dermatitis (eczema) - Type I hypersensitivity
Allergic contact dermatitis - Type IV hypersensitivity
What is seen clinically with psoriasis?
Histologically?
Scaling plaques on extensor surfaces
Auspitz sign
Histo - ^spinosum, thin granulosum, parakeratosis, long papillae
Can see nail pitting (little dents in nails) or psoriatic arthritis
What causes Leser-Trelat sign?
Leser-Trelat sign = sudden appearance of dozens of seborrheic keratoses. Indicates underlying malignancy (often GI).
What causes pemphigus vulgaris?
What is seen?
AutoAb against Desmoglein 1 and/or 3
Flaccid blisters & crusts involving skin AND ORAL MUCOSA
Reticular (fishnet) immunofluorescence
Acantholysis with tombstoning
Positive Nikolski’s sign (separation upon stroking of skin)
What causes Bullous pemphigoid?
What is seen?
AutoAb’s against Hemidesmosomes
Tense blisters with eosinophils on skin (spares oral mucosa)
Linear immunofluorescence along DEJ
What causes Dermatitis herpetiformis?
Anti-gliadin IgA Ab’s cross react with Reticulin in skin
Tiny blisters at the tips of papillae (elbows)
What can cause erythema multiforme?
What is seen?
HSV & other infections
Drugs
Cancers
Autoimmune disease
Targets with a red outside & dusky grey inside
What is seen with SJS/TEN?
Fever, bullae, sloughing of skin
Mucous membranes involved
If > 30% TBSA –> TEN
Usually caused by adverse drug reaction.
What is seen with acanthosis nigricans?
What causes it?
Hyperpigmented, velvety thick skin
Seen in neck, axilla, groin
Associated with:
Hyperinsulinemia
Visceral malignancy
What is seen with erythema nodosum?
What is it associated with?
Inflammatory red lesions of subcutaneous fat. Usually seen on anterior shins.
Associated with: Sarcoidosis Histoplasmosis & Coccidiomycosis TB & Leprosy Crohn's disease Streptococcal infections
What is seen with lichen planus?
What is it associated with?
6 P’s: Pruritic, purple, polygonal, planar papules & plaques
Seen on wrists, elbows, oral mucosa
Sawtooth infiltrate of lymphocytes at DEJ
Associated with HepC
What causes Pityriasis rosea?
What is seen?
Viral illness causes it somehow
Herald patch followed by Christmas tree distribution on torso
Resolves on its own in 6-8 weeks
Where are lower extremity venous & arterial ulcers seen?
Venous ulcers - Medial malleolus. Venous stasis dermatitis seen.
Arterial ulcers - Lateral malleolus
What is seen in Staphylococcal scalded skin syndrome?
Exfoliative toxins destroy keratinocyte attachments in the STRATUM GRANULOSUM (vs. SJS/TEN which is DEJ)
Fever
Rash with slouging
Heals completely
What are the relative incidences of skin cancers?
BCC > SCC > Melanoma
This also corresponds to their prognosis.
What are the risk factors for SCC of the skin?
Immunosuppression (most common malignancy) Arsenic exposure (think of the women who wanted light skin)
Common to all skin cancers:
Sun exposure
Albinism
Xeroderma pigmentosum
What is Keratoacanthoma?
A variant of skin SCC that grows rapidly & regresses spontaneously. It is cup shaped with keratin debris in the center.
What is the tumor marker for melanoma?
What mutation is commonly seen?
S-100 is the tumor marker (neural crest origin)
BRAF kinase activating mutation is common. If BRAF V600E –> treat with vemurafenib (BRAF kinase inhibitor).
What is the most important prognostic indicator of melanoma?
Depth of invasion
What are the subtypes of melanoma?
1) Superficial spreading (good prognosis)
2) Nodular (poor prognosis)
3) Lentigo maligna
4) Acrolentiginous (not related to UV; seen on palms & soles; seen in dark-skinned people)
What does the Lipoxygenase pathway produce?
What are their roles?
Lipoxygenase –> Leukotrienes (both start with L)
LTB4 - Neutrophil chemotaxis (they get there B4 everyone else)
LTC4,D4,E4 - vascular & bronchial SM contraction & vascular permeability
What is formed by the Cyclooxygenase pathway?
What are their functions?
TXA2 - platelet aggregation; constricts vascular & bronchial SM
Prostaglandins (PGE2, PGF):
^Uterine tone
Relaxes vascular & bronchial SM
Prostacyclin (PGI2):
Inhibits platelet aggregation
Relaxes vascular & bronchial SM
Relaxes uterine tone
What is used to close a PDA?
Indomethacin
It is an NSAID
What is Celecoxib used for?
What are its toxicities?
It is a reversible COX-2 inhibitor (NSAID). Spares the gastric mucosa & platelet function. It is used for RA.
Toxicities:
Thrombosis
Sulfa reaction
What is the mechanism of Acetaminophen?
It is a reversible COX inhibitor. It is inactivater peripherally & thus exerts its effects largely in the CNS –> analgesic, antipyretic, but not anti-inflammatory.
What is the mechanism of bisphosphonates?
What are they used for?
What are their toxicities?
Bisphosphonates (end in -dronate) bind hydroxyapatite in bone
–> inhibition of osteoclasts
Used for osteoporosis, Paget’s disease, hypercalcemia
Toxicities:
Pill esophagitis
Osteonecrosis of the jaw
What are the drugs for chronic gout management?
What are their unique characteristics?
Febuxostat - XO inhibitor; less drug interactions & less renal toxicity than allopurinol
Allopurinol - XO inhibitor; ^concentrations of azathioprine & 6-MP
Probenecid - inhibits PCT reabsorption of urate; ^penicillin levels; avoid if Hx of kidney stones
What are the TNF inhibitors?
All TNF inhibitors ^risk of reactivation TB & Hepatitis
Etanercept - fusion protein decoy receptor (fused w/ IgG Fc)
Infliximab/Adalimumab - mAb against TNF
Used for PAIR diseases & RA
What structures do these fetal structures give rise to? Truncus arteriosus Bulbus cordis Sinus venosus Right anterior & common cardinal veins
Truncus arteriosus –> ascending aorta & pulmonary trunk
Bulbus cordis –> outflow tract of LV & RV
Sinus venosus:
-Left horn –> coronary sinus
-Right horn –> smooth part of RA
Right anterior & right common cardinal vein –> SVC
From where is the aorticopulmonary derived?
Neural crest migration
What muscles are involved in abduction of the arm?
1) Supraspinatus (0-15 degrees)
2) Deltoid (15-90 degrees)
3) Trapezius & Serratus anterior (90-180 degrees)
What is tennis elbow?
Golfers elbow?
Tennis elbow = lateral epicondylitis (common extensor tendon)
Golfer’s elbow = medial epicondylitis (common flexor tendon)
What roots are injured in Erb-Duchenne palsy?
What nerves?
C5 & C6
Axillary, suprascapular, musculocutaneous
What can be injured with a posterior hip dislocation?
What is seen?
Superior gluteal –> trendelenberg sign
Inferior gluteal –> can’t get up from chair/climb stairs
What ligament is injured in an ankle sprain?
Anterior talofibular (lateral) ligament
What is seen with forced eversion of the ankle joint?
Pott’s fracture
Medial malleolus avulsed (deltoid ligament)
Fibula is fractured higher up
Where does the pain of costochondritis occur?
The left parasternal border
Usually affects >1 rib
Worsens with deep breathing
