MSK/rheum Flashcards
1
Q
Elderly pt with bullae. Histopathology with linear immunofluorescence at the dermal-epidermal junction
A
Bullous pemphigoid (BP) Autoimmune attack against hemidesmosomes
2
Q
Pathophysiology of Guillain-Barre (even if it follows gastroenteritis)
A
Autoimmune disorder against peripheral nerves and Schwann cells.
Histology = perivenular and endoneurial infiltration with lymphocytes, Macrophages, and plasma cells
Symmetrical ascension
3
Q
Pt unable to raise left arm. Leaves arm hanging at his side with forearm pronated
A
Erb palsy “waiters tip”
Upper trunk lesion
Affected muscles: abductors (deltoid, supraspinatus), lateral rotators (infraspinatus), and biceps
4
Q
Pt with dysphagia, claw like hand due to tightened skin, small flat red skin marks, Subq nodules, with significant cold sensitivity in her hands
A
CREST Syndrome, varient of scleroderma Calcinosis (skin nodules) Raynaud phenomenon Esophageal dysfunction Sclerodactyly (skin thickening) Telangiectasis (small red marks from dilated vessels Anticentromere antibodies
5
Q
Pt falling on outstretched hand, anterior shoulder dislocation likely
A
Axillary n. injury, inn deltoid. thus unable to abduct the shoulder
6
Q
Pt that can’t lift arm the first 15 degrees of abduction
A
Supraspinatus injury
Pt may comment that they can lift arm after passing the 15 degree point
7
Q
infant with lethargy, FTT, fever, increased head circumference, prominent hepatosplenomegaly with profound anemia and leukopenia. Autopsy shows infiltration of the medullary canal space by bony spongiose tissue
A
osteopetrosis
failure in bone remodeling due to osteoclast malfunction. medullary canal is replaced by bony matrix (loss of hemopoeitic material) and pts rely on extramedullary hematopoeisis. bone becomes brittle. AD version is more benign
8
Q
function of isoniazid
A
prophylactic TB med following +PPD but - CXR. decreases synthesis of mycolic acids.
can cause drug induced SLE (anti histone Ab)
9
Q
HLA type associated with RA and DM
A
HLA-DR4
10
Q
HLA associated with akylosing spondylitis, post gonococcal arthritis, acute anterior uveitis
A
HLA-B27
11
Q
HLA associated with Graves dz
A
HLA-B8
12
Q
HLA associated with kawasaki dz
A
HLA-BW22
13
Q
HLA associated with chronic active hepatitis, sjogren syndrom and T1DM
A
HLA-DR3
14
Q
appearance of gout aspirate
A
negatively birefringent crystals
15
Q
ca, phosphate, and alk phos in a pt with paget bone dz
A
nl ca, phos
high alk phos
16
Q
which muscle opens the jaw?
A
lateral pterygoid. inn by V3
17
Q
in a region of high prevalence what happens to PPV and NPV
A
PPV increases
NPV decreases
18
Q
pt with fatigue, headache, and blurry vision. can also have fever and jaw pain
A
temporal (giant cell) arthritis
tx with corticosteroids
19
Q
40-60yo pt with flaccid blisters that rupture leaving painful raw spots.
A
pemphigus vulgaris
autoimmune against desmoglein 3 in the desmosome and macula adherins (attaches epithelial cells together)
can be lethal
tx - corticosteroids
20
Q
if a kid punches a wall and fractures his hand he probably broke which bone?
A
metacarpals “boxers fracture”
21
Q
Mechanism of action of Tacrolimus
A
post transplant immunosuppresant
Inhibits calcineurin - inhibits T lymphocyte signaline
22
Q
Test used to dx myasthenia gravis? Potential complication?
A
Test - ACh receptor Ab
Complication - thymomas (widened mediastinum)
tx - AChEI (pyridostigmine)
23
Q
In long bone ossification
A
endochondral ossification = osteoblasts secrete osteoid over a hyaline cartilage model (woven bone)
24
Q
Pt with fractures with a CBC showing:
elevated Calcium
Low Phosphate
High Alk phos
A
osteitis fibrosa cystica, a complication of untreated hyperPTH (too much reasorption, brown tumor in bone)
25
Pt with bone dz and:
NL calcium
NL Phosphate
High Alk Phos
Paget dz
| Overactivity of clasts and blasts with sclerotic and lytic lesions on CXR
26
Desmosomes are joined by
Tight junctions
27
Lab finding in a patient with sausage like fingers and a scaly rash
Psoriatic arthritis
| Elevated ESR
28
Underlying genetic cause of achondroplasia
Defect in Fibroblast growth factor receptor 3 (FGFR3)
| AD
29
Polymyalgia rheumatica is closely associated with?
Giant cell Arthritis (Temporal Arthritis)
30
common complications of ankylosing apondylitis
uveitis
| aortic regurgitation
31
pt that has difficulty standing, walking up stairs, or jumping following a posterior hip location damaged which nerve?
inferior gluteal n.
| inn gluteus maximus
32
pt falling on outstretched hand with pain in snuff box but negative XR likely has?
scaphoid fx
pain on lateral wrist on dorsiflexion and abduction
bone will undergo avasculaf necrosis and will be hypodensd on depeat XR
33
if a pt leaves a mid shaft humoral fracture that is displaced go untreated they risk losing function of?
muscles inn by the radial n.: brachioradialis
34
if a pt has hoarsness following a thyroidectomy which branchial sturctures may have been damaged?
branchial arch 4 - laryngeal n.
| branchial arch 6 - recurrent laryngeal n.
35
what type of tissue arises from branchial:
groove
arch
pouch
```
groove = ectoderm
arch = mesoderm
pouch = endoderm
```
36
in erb-duchenne which muscles are affected?
biceps, deltoid, infraspinatus, supraspinatous
| c5-c6
37
kid with leg pain and intermittent fevers. bx shows uniform cells with scant clear cytoplasm and no evidence of normal bony matrix
ewing sarcoma
anaplastic small blue cells
onion skin lesion on XR
t11;12 translocation
38
pt rolls ankle inward and presents with forward displacement of talus likely injured which ligament?
anterior talofibular ligament
| most common lateral ligament injury of the foot because it is the weakest
39
muscles that elevate the pharynx are derived from which embryological structure?
branchial arch 3 - stylopharyngeus m. (CN IX)
| branchial arch 4 - levator veli palatini m. (CN X)
40
following statin initiation, pt presents with increased BUN, creatanine, and tea colored urine due to?
acute tubular necrosis secondary to myoglobin release from rhabdomyolysis.
41
young male pt presents with leg pain and a fhx of sister with eye cancer. bx receals malignant bone dz
osteosarcoma
metaphyseal region of long bone
XR = sunburst pattern
associated with Rb mutation
42
30-60 yesr old male with cancer in the pelvis, spine, scapula, humerus, tibia, or femur
chondrosarcoma
43
older male pt with pelvic pain and XR demonstrating blastic lesions
metastatic cancer secondary to prostate cancer
| osteolytic lesions = colorectal
44
direct inguinal hernias pass through x and are bordered by
protrude through hasselbach triangle (which can include through the external inguinal ring)
border = inguinal ligament (inferior), rectus abdominous medially, and inferior epigastric vessels laterally
45
indirect inguinal hernias pass through x and are bordered by
pass through internal inguinal ring (patent processus vaginalis) and enter scrotum
46
pt with recent allergies, asthma, uveitis, mild hearing loss, parathesia, diffuse joint pain, weak DTR, and eosinophilia
churg-strauss
| check p-anca
47
slashing the medial aspect of the wrist may damage the?
ulnar n.
adductor pollicis m.
may have a claw hand
48
man lifts a box over his head and tears a muscle. has weakness on medial rotation of the arm. pt likely injured his
subscapularis m.
49
sle patient that also has a positive VDRL likely has?
anti-smith ab
this is an autophospholipid ab that reacts to cardiolipin
ana = sensitive to sle
anti-smith and anti-dsdna ab = specific for sle
50
pt with muscle weakness and heliotrope rash
defmatomyositis
| anti-jo1 ab
51
a pt with gastritis that is requesting a medication to control his pain secondary to osteoarthritis should receive
celecoxib
| cox 2 inhibitor Vijds exacerbation of gastritis
52
what are the steps in smooth muscle contraction
AP activates voltage gated calcium channels
calcium binds calmodulin and activates myosin light chain kinase
mlck phosphorylates myosin allowing it to crossbridge with actin
53
what nerve and muscle can be injured following a mastectomy causing winging of the scapula?
serratus anterior m.
| long thoracic n. (c5, c6, c7)
54
which drugs are used in chronic gout by competing with uric acid for resorption in the kidney
probenecid, sulfinpyrazone
55
what drug is used in acute gout by limiting the inflammatory response to urate crystals
colchicine
56
in ortner syndrome, the left atrium produces hoarseness by compressing?
the left recurrent layngeal n. a branch of the vagus n.
57
following a humoral fracture a pt may have difficulty with which motion?
extending the wrist, forearm supination
decreased brachilradials reflex
radial n. damage
58
in carpal tunnel syndrome
which nerve is compressed ?
which fingers become weak?
sensation can be list where?
median n. compression
thumb weakness
loss of sensation over palmar aspect of second digit
59
in complete thrombosis of the radial a., which vessels can provide collateral flow in the hand?
arteries of the deep and superficial palmar arch
60
a baseball pitcher is unable to laterally rotate his arm most likely injured his?
infraspinatus m.
61
in the second phase of pager dz, how does the pts levels of ca, alk phos, and phos change?
stage 2= mixed period of bone formation
nl phos
nl to slightly elevated ca
alk phos high (400ish)
62
following treatment for a fungal skin infection a pt has hyperpigmentation. which drug was used?
ketoconazole
occurs due to desmolase inhibition causes decreased levels of cortisol and melanocyte stimulating hormone loses its feedback inhibition
63
an epileptic pt receives treatment and weeks later presents with stevens-johnson syndrome. what is the drug?
lamotrigine
| alsophenytoin, ethosuximide, carbamazapine
64
appendicitis symptoms will follow which dermatomal distribution?
T10, T12
| T10 controls the belly button (but ten)
65
a pt undergoing a muscle stimulation test that improves after repeat stimulation
Lambert eaton syndrome
| ab against presynaptic ca channels
66
the cremaster m. is formed from the?
internal oblique m.
67
in a pt with OA what structural changes might you expect on histology of the joint space?
dislodged pieces of cartilage and subchondral bone
68
what mutation is found in becker muscular dystrophy
in frame deletion
| these guys have the weakness symptoms, but do not have intellectual disabilities
69
what mutation is found in duchenne muscular dystrophy?
out of frame deletion. truncated protein
70
inheritance pattern through maternal mitochondria
heteroplasmy
71
hx of seizures and ragged muscle fibers on bx
mitochondrial encephalomyopathy
| heteroplasmy
72
pt presenting with squamous cell lung cancer and hypercalcemia but no focal lytic bone lesions
humoral hypercalcemua of malignancy
caused by over secretion of parathyroid hormone related protein (causes increased resorption of bone but no increase in renal excretion)
73
mechanism of Clostridium perfingens toxin
gas gangrene
| toxin = lecithinase, AKA phospholipase C. splits phospholipid molecules
74
40ish woman with multimonth history of fatigue and widespread MSK pain and decreased attention. soft tissue tenderness at multiple locations bilaterally
fibromyalgia
chronic pain and fatigue for 3+ months in the absence of other syndromes/causes
tx - incremental aerobic exercise
75
50+ hear old woman with pain and stiffness in shoulders and hips, weight loss. fever, malaise
polymyalgia rheumatica
76
which muscle plays the largest role in the valsava maneuver?
rectus abdominus muscles
77
which circuit provides a negative feedback system to regulate and maintain muscle tension?
golgi tendon organs
| can inhibit contraction of a muscle that is exerting too much force (ie weightlifting) to avoid damage
78
which feedback system monitors muscle length and prevents over stretching?
muscle spindle system
79
mechanism of action for first line treatment in an acute gout attack?
colchicine
inhibits tubulin polymerization and disrupts PMN chemotaxis and phago
side effects =nausea, abdominal pain, diarrhea
80
What two factors determine bone mass?
Peak bone mass (largely genetic)
| Rate of bone loss
81
Infant presenting with floppiness (hypotonia) and poor feeding. Stools are every other day and pellet-like. On PE large anterior fontanelle, large tongue, reducible umbilical hernia, low muscle tone.
Congenital Hypothyroidism
Caused by throid dysgenesis and iodine deficiency (european family). No symptoms initially since maternal T4 crosses placenta
T4 is involved in mylination in early life and infant is at risk of irreversible intellectual disability
Tx with levothyroxin in first 2 weeks of life to protect brain function
82
Pt with progressive weakness and difficulty combing his hair. No history of injuries. Bx shows MHC I overexpression on the sarcolemma with CD8+ lymphocyte infiltration
Polymyositis
| Note: no heliotrope rash (dermatomyositis)
83
Kid with recurrent skin and mucosal infections, no pus, poor wound healing.
Leukocyte adhesion deficiency
Can have delayed cord seperation at birth
At risk for peripheral leukocytosis with neutrophilia
84
Leukocyte adhesion deficiency is characterized by the absence of?
CD18 - necessary for integrin formation which is essential for adhesion
85
Pt with a thoracic compression fracture
Osteoperosis
86
Initiating allopurinol treatment increases activity of which medication?
Azathioprine
Inhibition of XO results in increased conversion of azatioprine to 6-thioguanine which incorporates into DNA and suppresses bone marrow leukocyte production.
87
A humoral fracture puts which vessel at risk?
Deep brachial a.
88
Staph aureus has the virulence factor Protein A. What does it do?
Part of the outter PPG layer
Protein A binds the Fc portion of IgG Abs at the complement binding site to prevent complement activation. Causes decreased C3b production and impaired opsonization and phagocytosis
89
In a patient with giant cell arteritis, what is the most important mediator of this dz?
Interleukin-6
| Tocilizumab is an mAb against IL6 and is effective in treating GCA
90
On PE of an injured knee, there is widening of the medial joint line when valgum force is applied on the lateral knee with the lower leg fixed. What is injured?
Medial collateral ligament
Attaches medial epicondyle of femus
Typically occurs after a twisting injury
91
A pt periodically has involuntary deviation of the head to the right with shoulder/neck pain lasting 30-40 minutes. It can be suppressed by placing a hand on the chin. This is?
Dystonia (spasmodic toricollis is cervical dystonia)
| Sustained, involuntary muscle contraction
92
What is blepharospasm?
A focal dystonia involving involuntary forceful closure of the eyelids.
93
Sudden, brief, severe muscle contraction
myoclonus
94
Intermittent resistance in extension/flexion of a limb
Cogwheel rigidity
| Parkinsons
95
Slow movement
Bradykinesia
| Parkinson
96
Involuntary muscle activity that flows from on muscle group to another. Can be fragmented or jerky
Chorea
| Huntington
97
Flinging of the limbs on one side of the body
Hemiballism
| Contralateral injury to the subthalamic nucleus
98
child fell on outstretched hand and now holds his right arm at this side with elbow extended and forearm pronated. He injured the?
Annular ligamnet displacement
Radial head subluxation (nursemaid elbow)
Generally only occurs in kids under the age of 5
99
Multinucleated cell in Paget dz
osteoclast
| Accumulation of monocytes
100
2 factors imporant in osteoclast differentiation
Macrophage colony-stimulating factor (M-CSF)
| Receptor for activated nuclear factor kappa-B ligand (RANK-L)
101
What is the physiologic decoy receptor that decreases binding of RANKL to RANK?
osteoprotegrin (OPG)
This reduces differentiation and survival of osteoclasts
Loss of function mutation = juvenile Paget's dz
102
Late onset asthma, rhinosinusitis, eosinophilia that potentially has kidney, GI, or CV sysmptoms. Can have carpal tunnel like symptoms
Eosinophilic granulomatososis with polyangiitis (Churg-Strauss)
Mononeuritis multiples = vasculitis affecting epineural vessels (carpal tunnel symptoms)
Lab finding = Ab against PMN myeloperoxidase and perinuclear p-ANCA
103
Asymptomatic chronic smoker with digital clubbing, thickening of distal phalanges. Fingers have drumstick appearance, flat nail folds, and shiny distal fingers. Spongy nail beds. Causes?
Lung dz - TB, CF, bronchiectasis, pulm HTN etc
Heart dz - Cyanotic congenital heart dz, bacterial endocarditis
IBD
hyperthyroidism
malabsorption
104
First line therapy for a newly diagnosed RA pt?
Prednisone
Inhibits phospholipase A2
Methotrexate, sulfasalazine require weeks before providing symptom relief
105
Pt with acute knee pain with 3 similar episodes that resolved with OTCH analgesic. History of polycythemia and non compliant with phlebotomy. What is found on needle aspiration?
Needle shaped, negatively birefringent crystals
| Myeloproliferative disorders increase urate production
106
Can osteoarthritis pts have morning stiffness?
Yes but brief
107
Pt has a puncture injury on right leg. Right foot is dorsiflexed and everted. Cannot stand on toes. Knee and hip muscle strength are intact. Pedal and tibial pulses are +2 and symmetric. XR negative for fracture. Pt will have sensory loss where?
Tibial n. injury at the popliteal fossa, causes foot plantarflexion
Plantar foot
108
In a clavicle fracture, what muscle will displace the medial fragment superiorly?
SCD m.
109
In a clavicle fracture, which muscle will displace the lateral fragment superiorly?
Trapezius m.
110
Pt with fever, flank pain, difficulty walking x 3 days. Pt lies supine with R knee flexed and externally rotated. Resists extension of the leg, thigh and hip
Psoas major abscess
111
Pt with Black stools, fever, weight loss, muscle pain. Smoker and IVDU. Muscle bx shows transmural inflammation of the mid-sized arteries with areas of homogenous, eosinophilic arterial wall necrosis. Areas of internal lamina disruption
Polyarteritis nodosa secondary to Hep B
112
Pt with claudication, ulceration, and gangrene. Bx shows inflammatory thrombosis and ischemia involving small and medium arteries of the extrremities
Thromboangiitis obliterans (Buerger dz) secondary to smoking
113
In acute gout, and medication is given that selectively binds IL1
Celecoxib
| IL1 is only expressed in sites of inflammation
114
A pt was given a muscle relaxant prior to intubation. He develops vfib and his potassium climbs to 19. Which agent caused this?
Succinylcholine
Depolarizing neuromusclular blocking agent that is not broken down by AChesterase
Does cause significant K+ release and arrhythmias
115
A pt with a laceration is presenting 3 weeks later with high levels of actin-containing fibroblasts and increased metalloproteinase activity
Contracture - when excessive MMP activity causes excessive wound contraction (deformities)
MMPs degrade collagen and ECM proteins. Important in would healing
116
If giant cell arthritis is suspected, what should be ordered before performing a biopsy?
CRP or ESR
Sensitive but not specific
bx = specific
117
A kid with a recent illness is now limping and refusing to put weight on his leg. Likely has osteomyolitis. Where is the infection?
Long bone metaphysis - slow flow makes the microbe happy
| Adults are less likely to develop hematogenous osteomyelitis due to closure of the epiphysial plate
118
A pt has difficulty climbing stairs and getting up from a chair, diplopia, dry mouth. Previous SHx of nailing his right tibia. 45 ppd smoking history, Erectile dysfunction. Decreased DTR's, CXR shows irregular round mass in the Right upper lobe
Lambert-Eaton myasthenic syndrome
Proximal muscle weakness, cranial n. involvement, autonomic syx (dry mouth, ED)
Approx half of LEMS pts have an associated malignancy (usually small cell lung cancer)
NOTE: LEMs have hyporeflexia, autonomic syx, and respond to repeat stimulation but MG does not
119
Scaphoid fx are at risk for which two complications?
Avascular necrosis
| Nonunion
120
Post oophrectomy research animals have overexpression of RANK on the surface of bone cells. What is the effect of this?
Increased bone resorption
RANK-L is not able to interact with rank with RANK when osteoprotegrin is present because it is a decoy receptor. When OPG binds RANK-L it reduces the survival of osteoclasts
Bone turnover is regulated by OPG:RANK-L
High RANK-L - resorption, high osteoclast activity
High OPG - high formation, osteoblasts
121
A resting membrane potential is -70mV, which ion will flow out of the cell?
Potassium (-90)
| Cl is also an anion but it has a low intracellular concentration
122
Follow a patellar fx, a pt has parathesia and numbness at the dorsum of the right foot and weak dorsiflexion. Where is the nerve compression?
Fibular neck
Common peroneal n.
Causes weak dorsiflexion and impaired senstation over the dorsal foot and lateral shin
123
Aside from elevated auto Ab what other lab abnormalities will SLE pts have?
decreased C3 and C4
124
Anti mitochondrial ab are found in pts with?
Primary biliary cirrhosis. Presents with pruritus, jaundice, malabsorption
125
A pt presenting with fatigue, dyspnea, and noncaseating granulomas most likely will have elevated calcium due to?
Activated Macrophages produce 1-a-hydroxylase which activates PTH-independent production of 1,25-dihydroxyvitamin D. This causes increased intestinal reabsorption of calcium
Sarcoidosis pt
126
A pt with RA is likely to see the dz spread to?
The cervical spine (sublaxtion, cord compression)
127
A pt is presenting with M. leprae (skin discoloration, epistaxis, loss of eyebrows/eyelashes). What should be given to alleviate his symptoms
Interferon gamma
M. leprae is controlled by Th1. Th1 secretes IFN gamma which activates macrophages. So, supplementing some IFN gamma helps the pt get ahead of the curve.
128
A neonate presents with FTT, lethargy, increased head circumference, hepatosplenomegaly, anemia, leukopenia. Bone marrow space revels infiltration of the medullary canal with primary bony spongiose tissue. Dx and pathology
Osteopetrosis
Malfunction of osteoclasts - failure of resorption and remodeling of bone. pts compensate with extramedullary hematopoiesis (large head, hepatosplenomegaly)
129
High alk phos, high calcium, low phos. Multiple fx in a low speed MVA
Osteitis fibrosa cystica
Consequence of untreated hyperPTH leading to over active osteoclasts.
Lesions on XR
130
An older adult with elevated elk phos should be evaluated for?
Suggestive of metastatic dz
lytic lesions = multiple myeloma, thyroid, kidney
Sclerotic lesions = prostate
Mixed lesions = breast and lung
131
Abx prescribed for acne that increases photosensitivity
Tetracyclines
| Bind 30S
132
The palatoglossus m. is inn by the?
Recurrent laryngeal n.
| Compression of this n. = hoarseness (Ortner syndrome)
133
Cellular structure at the dermal epidermal junction?
Hemidesmosome
| Targer in bullous phemgoid
134
A pt has a non erythematous peraly dome shaped papule that is not pruritic
Molluscum contagiosum
Poxvirus
Spontaneous resolution after a few months
135
After lifting a heavy object a pt has weakness when medially rotating his arm. Which muscle is injured?
Subscapularis m.
| medial rotation and adduction
136
What is Behcet dz?
Autoimmune vasculitis characterized by oral and genital aphthous uclers
HLA - B51
137
HLA B27 is associated with
Psoriasis
Ankylosing spondylitis
IBD (UC and Chron's)
Reactive arthritis
138
Pt presents with multiple fx after falling downstairs. On Xray, some of the fx are new and some are old. Labs: low vit D and phos, low-to-nL Ca2+, high alk phos. Dx?
Osteomalacia
Areas of unmineralized osteoid adjacent to normal trabeculae
Caused by vit D deficiency (with secondary low phos) due to malnourishment
139
The only rotator cuff muscle that can medially rotate the arm?
Subscapularis m.
140
An immigrant presents with multiple numb cutaneous and erythematous skin plaques and nodules, especially over the extremities and butt. Recent loss of eyebrows and eyelashes and several episodes of epistaxis. PMH includes childhood asthma and atopy. Which cytokine would improve his condition?
IFN gamma
Pt has Mycobacterium leprae. It is controlled by Th1 cells which secrete IFN gamma.
Severe lepromatous dz occurs with CD4+ cells differentiate into Th2 instead of Th1. Giving IFN gamma would activate the macrophages which recruite Th1 to the sites of infection.
IL-10 would be a terrible idea because it would further down regulate the Th1 immune response
141
After falling off of his horse a pt is unable to raise his left arm and lets it hang by his side pronated. Which nerves and muscles are involved?
Erb palsy, waiter's tip
Upper trunk of brachial plexus(C5-C6)
affects the deltoid, supraspinatus, infraspinatus, and biceps
142
Inheritance pattern for Duchenne Muscular Dystrophy?
X - linked, Xp21 - dystrophin which is a myocyte anchoring protein
By age 5 - delayed walking, clumsy, weak, enlarged calf muscles (pseudohypertrophy)
Elevated creatine kinase
143
If PIP and DIP are involved think?
OA
| If just PIP and metacarpal think RA
144
What step in muscle excitation is unique to smooth muscle?
Phosphorylation of myosin
AP depolarizes myocyte mumbrane -> opens VGCC -> Ca 2+ binds and activates calmodulin -> activates myosin light-chain kinase -> phosphorylates myosin allowing for cross bridging (NOTE - phosphorylates for contraction, not relaxation)
145
Steps in contraction of skeletal m.
AP terminates on muscle fibers and release ACh -> binds sarcolemma -> signal moves to T-tubules -> Ca2+ release from sarcoplasm reticulum via ryanodine receptors -> Ca2+ binds troponin C -> conformation change in tropomysin allows actin to interact with myosin (note in Smooth m. actin phosphorylates myosin but does NOT bind) -> crossbridge = contraction
146
Which muscle pulls the testicles into the abdominal cavity to maintain temperature?
Cremaster m.
| Derived from Internal oblique m.
147
RA is associated with which HLA?
HLA-DR4
| Also DM
148
HLA-DR3 is associated with?
Chronic acitve hepatitis
Sjogren syndrome
T1DM
149
Spinal stenosis is caused by thickening of which ligament?
Ligamentum flavum
Common in lumbar regions and presents with posture dependent lower extremity pain, numbness/parethesia, and weakness.
Most common cause is degenerative arthritis of the spine which results in narrowing of the spinal canal due to intervetebral disc herniation, ligamentum flavum hypertrophy, and osteophyte formation affecting the facet joints
150
What type of inhibitor allows the enzyme to reach the same Vmax but additional substrate is required to reach the max velocity (increases Km).
Competitive inhibitor
151
What would be a good tx for a 40ish female pt with a vertebral fx and fam hx of breast cancer?
Raloxifene - SERM. Estrogen agonist in bone to prevent osteoporosis but antagonist in breast tissue
Tamoxifen would not be a good fit because although it is an antagonist in breast tissue and an agonist on bone (to reduce Osteoperosis) it is also an agonist on the uterus and limits its osteoperosis efficacy
152
Embryonic origin of the thymus and inferior parathyroids?
```
3rd pouch
Superior parathyroids (4th)
```
153
What type of junctions are found between osteocytes?
Gap junctions
Long intracanalicular processes that extend through the bone matrix.
Allow for transmission of signals and nutrient exchange
Help regulate bone remodeling by communicating with surface osteoblasts
154
Ab against snRNPs?
Anti-Smith
| Specific for SLE
155
Pt with lung cancer plus proximal muscle weakness (difficulty getting out of a chair) and diplopia?
Lambert-Eaton syndrome
| Usually small cell lung cancer
156
A pt on TB regimen presents with Anti-histone Ab and ANA. Dx?
Drug induced SLE
Linked to drugs that are metabolized by N-acetylation in the liver (procainamide, hydralazine, isoniazid)
Slow acetylators are at greater risk of drug induced SLE
157
A myasthinia pt is started on tx and presents with abd cramping, nausea, sweating diarrhea. Tx?
Scopalamine
Tx - MG with a cholinesterase inhibitor (pyridostimine) and has excessive muscarinic GI syx due to excessive cholinergic stimulation
Scopalamine is a selective muscarinic ACh receptor antagonist
158
Tx for Lyme dz?
Doxycline
Penicillin type abx (ceftriaxone)
Early lyme - rash
Early disseminated - facial palsy, AV node block
Late lyme - asymmetric arthritis, encephalopathy
159
adult Sickle cell Pt presents with hip and pelvic pain due to?
Avascular necrosis
| Pain + restricted movement
160
Decreased levels of complement C3 and C4
SLE
| ANA, anti-dsDNA, Anti-Smith
161
Gottron papules, heliotrope rash, muscle weakness
```
Dermatomyositis
Gottron papules = red or violaceous, flat-topped papules over joints and bony prominences
ANA, anti-Jo1
perimysial inflammatory infiltrate
Can be part of a paraneoplastic syndrome
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162
Infant with constipation, lethargy, hypotonia, macroglossia, umbilical hernia, large anterior fontanelle?
hypothyroidism
Start on levothyroxine by 2 weeks
Protected in utero due to maternal T4
163
Man presents with pain in multiple joints. Blue-black spots on sclerae and darkening of the auricular helices. Dx?
Alkaptonuria
Deficiency in Homogentisic acid dioxygenase deficiency
ar, defect in tyrosine metabolism
Black deposits due to excess homogentisic acid
164
Anti-Jo 1 is directed against?
anti-histidyl-tRNA synthetase
| Polymyositis - endomysial mononuclear inflammatory infiltrate and patchy necrosis of muscle fibers
165
What do all seronegative spondylarthropathies have in common?
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HLA-B27
Human Leukocyte antigen class I serotype
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166
Calcium pyrophosphate deposition in the synovial fluid is diagnositc of?
Pseudogout
| Positively birefringent under polarized light (blue)
167
Which HTN med can increase Ca2+ reabsorption and be protective in osteoperosis?
Thiazides
Recommended for HTN tx in pts at risk of osteoperosis
Loops diurectics shed calcium
168
In paget's dz of the bone, the initial phase is dominated by which cell type?
Osteoclasts - increased activity
Bone pain + elevated alk phos in an elderly pt = Paget dz of the bone
Bx of mosaic pattern of lamellar bone is diagnostic
169
Phases of pagets dz of the bone?
osteolytic
Mixed
Osteosclerotic
170
Muscle bx that is myoglobin-rich, glycogen poor with many mitochondria is characteristic of?
Postural skeletal muscles (soleus, paraspinal)
Type I slow twitch
ATP from aerobic metabolism
171
Pt is put on a muscle relaxant and repeat muscle stimulation is decreased but equal initially but 30 min later a similar pattern to what would be seen in myasthenia gravis. What is the drug?
Succinylcholine
Fast acting depolarizing agent. Short administration (phase I blockade) has equal reduction but prolonged administration causes non depolarizing block (think MG pattern)
172
12 y/o girl has arthralgias and a + ASO titer. What is she at risk of developing?
Pancarditis (primary cause of morbidity in acute rheumatic fever)
173
Pathologic process of giant cell arteritis?
Granulomatous inflammation of the media
Usually involves branches of the carotid (esp temporal)
Tx - glucocorticoids
