March 13 - Rheumatology Flashcards
TNF-alpha inhibitors: MOA, use, ADRs
MOA: etanercept acts as TNF-alpha decoy receptor, infliximab works as monoclonal anti-TNF antibody
Use: moderate to severe rheumatoid arthritis, especially for those that have failed methotrexate
ADRs: impaired cell mediated immunity. Especially important for maintenance of granulomas - should screen for TB prior to starting therapy
Biosphosphanates: MOA
inhibit mature osteoclast-mediated bone resorption by binding to hydroxyapatite binding sites
Treatment of acute gout
First line: NSAIDs
Second line: colchicine (inhibits MT polymerization, disrupting chemotaxis, phgocytosis, degranulation)
Contracture formation
Results from excess MPP activity. MPPs ecourage myofibroblast accumulation and scar tissue remodeling, leading to contracture
Bones of wrist
From lateral to medial and proximal to distal:
- scaphoid
- lunate
- triquetrum
- pisiform
- trapezium
- trapezoid
- capitate
- hamate
Osgood-Schlatter disease
Overuse injury of secondary ossification center of tibial tubercle. Seen in adolescent athletes following growth spurt. Presents with pain and swelling at tibial tubercle where the patellar ligament inserts.
Tibial nerve: course and what it innervates
Goes through popliteal fossa and into posterior compartment of leg
Motor innervation to posterior compartment muscles and intrinsic foot muscles. Responsible for inversion, plantarflexion, toe flexion.
Sensory innervation to sole of foot
Superficial peroneal nerve and deep peroneal nerve: sensory innervation
Superficial: lateral legg, dorsal foot, medial foot
Deep: Skin between 1st and 2nd toes
Pharyngeal pouches 1-4
1 - middle ear and auditory tube
2 - palatine tonsil crypts
3 - thymus, inferior parathyroids
4 - superior parathyroids, ultimobranchial bodies
CREST syndrome: symptoms and autoantibody
Symptoms
- calcinosis
- raynaud’s
- esophageal dysmotility
- sclerodactyly
- telangiectasias
Anti-centromere antibodies
Succinylcholine: MOA and side effect
Depolarizing NMJ blocker. Attaches to nAChR but isn’t degraded by AChE resulting in continued stimulation and inactivation of sodium channels. Because nAChR is a non-selective cation channel, prolonged opening can lead to excess K+ release and hyperkalemia. This isn’t seen with non-depolarizing NMJ blockers which don’t open the channe.
Giant cell arteritis: symptoms, diagnosis, treatment, and histology, patient population
Symptoms: headache, jaw claudication, visual disturbances (ischemic optic neuropathy), polymyalgia rheumatica (achy pain in shoulders and hip girdles)
Diagnosis: temporal artery biopsy
Treatment: glucocorticoids
Histology: granulomatous inflammation of media with giant cells (same as Takayasu) in branches of carotid artery. segmental lesions.
Patient population: women over 50
Takayasu arteritis: histology, population, presentation
Histology: granulomatous inflammation in aortic arch branches
Population: young Asian females
Presentation: pulseless disease
Polyarteritis nodosa: population, pathology, arteries affected
Population: Young adults, associated with hep B (pos surface antigen)
Pathology: early lesions: transmural inflammation with fibrinoid necrosis; late lesions: massive fibrosis resulting in nodes
Arteries affect: all organs but lung is spared
Kawasaki disease: population, presentation, arteries involved, treatment
Population: Kids less than 4
Presentation: Rash on palms and soles, conjunctivitis, fever, enlarged cervical nodes
Arteires: coronary a
Treatment: aspirin and IVIG to protect against thrombus in coronary artery
Buerger disease: presentation, population
Presentation: affects digits, associated with Raynaud phenomenon
Population: Smokers
Wegener’s disease: pathology, presentation, diagnosis, treatment
Pathology: necrotizing granulomatous inflammation
Presentation: affects nasopharynx, lungs, kidney
Diagnosis: pos c-ANCA
Treatment: cyclophosphamide
Microscopic polyangiitis: presentation
Affects lung and kidney but no nasopharyngeal involvement. No granulomas. Pos p-ANCA
Churg-Strauss disease: presentation, pathology
Presentation: Affects lungs and heart. Associated with asthma. Peripheral eosinophilia. Positive p-ANCA
Pathology: granulomas
HSP: presentation, treatment
Presentation: palpable purpora in butt and legs of a kid due to IgA deposition, IgA nephropathy, occurs following UTI
Treatment: steroids if severe
Muscles of rotator cuff: function and innervation
Supraspinatus: abduction, suprascapular n
Infraspinatus: external rotation, suprascapular n
Teres minor: adduction and ext rotation, axillary n
Subscapularis: adduction and int rotation, upper and lower subscapular n
Joint disease and myeloproliferative disorders
Associated with acute gout– increased cell turnober results in increased urate production
Radial head subluxation (nursemaid’s elbow)
Caused by pull on the arm while extended and pronated. Traction causes annular ligament to tear and slip over the head of the radius and get trapped. Seen in kids as the annular ligament is weak.
Classic bone findings: rickets
Increase in unmineralized osteoid, widening between osteoid seams
Classic bone findings: osteoporosis
Decrease in total bone mass, trabecular thinning
Classic bone findings: hyperparathyroidism
Subperiosteal thinning
Classic bone findings: paget’s disease
Mosaic lamellar bone
Classic bone findings: osteopetrosis
Persistence of primary unmineralized lamellar bone in the medullary canals which is normally replaced by bone marrow
Trendelenberg sign
Contralateral hip drop. Seen in superior gluteal nerve injury – damage can occur with injection into the superomedial quadrant of the buttock
Pathophysiology of osteopetrosis
Inherited defect in bone resorption resulting in thick heavy bone. One cause is carbonic anhydrase 2 mutation: acidic environment needed to remove Ca++ from bone.
Osteoclast: cell charactersitics, changes in Paget’s disease
Phagocytic lineage. Precursors fuse to form multinucleated mature cell. In Paget’s disease, can get very large containing over 100 nuclei as oppsed to 2-5.
Osteoclast differentiation
Driven by M-CSF and RANK-L (receptor for activated nuclear factor kappa B). RANK-L produced by osteoblasts and marrow stroma and interacts with RANK.
Osteoprotegerin (OPG) is a RANK-L decoy receptor that inhibits the interaction between RNAK-L and RANK, decreasing the differentiation and survival of osteoclasts
Reactive arthritis presentation
Arthritis, conjunctivitis, and urethritis following GI or GU infection
Lymphatic drainage of leg
Medial tracts: follow long saphenous vein to superficial inguinal nodes, bypassing popliteal nodes
Lateral tracts: communicate with both popliteal and inguinal nodes
Hematogenous osteomyelitits: population, pathophys
Population: young boys
Pathophysiology: Affects metaphysis of long bones which contains slow flowing vasculature conducive to bacterial growth. Bone marrow is seeded leading to inflammation and necrosis and spread of infection along hte periosteum
Drugs that can increase risk of osteoporotic fracture (other than the obvious)
- CYP450 inducing anticonvulsants (increase vit D catabolism)
- PPIs: decreased Ca++ absorption (acidic environment needed for Ca++ absorption)
- Unfractionated heparin: decrease bone formation
- Thiazolinediones: decrease bone formation
SERMs: tamoxifen vs raloxifene
Tamoxifen: used to treat breast cancer, agonist on endometrium
Raloxifene: used for postmenopasual osteoporosis, netural at endometrium
Golgi tendon organ
Sensory receptor at junction of muscle and tendon. Innervated by 1b sensory axons. Connected in series with extrafusal fibers. Detects increase in tenstion that occurs when contract against resistance. Acts to provide negative feedback to muscle so that if exert too much force, there is sudden muscle relaxation to prevent MSK damage,
Muscle spindle
Intrafusal muscle fibers organized in parallel with extrafusal fibers. Innervated by Ia and II sensory fibers. Sensitive to changes in muscle length, mediating stretch reflex by activating alpha motor neuron of same muscle in response to stretch
Four types of sensory receptors in skin
Pacinian corpuscles: rapidly adapting, deep
Ruffini endings: slow adapting, deep
Meissner corpuscles: rapidly adapting, shallow
Merkel discs: slowly adapting, shallow
Spinal involvement in RA and OA
RA: cervical spine
OA: lumbar spine
Femoral nerve: course and neuropathy
Descends through the psoas, emerges laterally, and then goes under the inguinal ligament into the thigh.
Damage results in weak quads, decreased patellar reflex, sensory loss over anterior and medial thigh and medial leg
Differentiating between polyarteritis nodosa and churg-strauss
Both cause transmural inflammation but polyarteritis nodosa affects mid sized vessels which churg strauss affects small vessels
Valsalva maneuver
forcibly exhale against closed glottis. Recruits rectus abdominus, resulting in increased intraabdominal and intrathoracic pressure
Azathioprine and allopurinol
Azathioprine is immunosuppressive agent used to prevent organ rejection and in autoimmune disorders. Purine analogue. Can be converted to active metabolites by HGPRT or inactive metabolites by xanthine oxidase. Allopurinol, which inhibits xanthine oxidase, blocks converstion to inactive metabolites therefore increasing conversion to active metabolites
Parvovirus B19 infection in adult
Causes acute arthritis that mimics RA. Immune complex mediated.
Hypercalcemia of sarcoidosis
Activated macropahges increase production of active vitamin D, increasing Ca++ absorption.
Latissimus dorsi: function
Extension, adduction, and internal rotation of arm
