Musculoskeletal + Skin Flashcards
Osteomyelitis in kids usually seeds where?
Metaphysis of long bones
Dystonia - definition and cause
Prolonged repetitive muscle contractions.
Occurs as a result of impaired basal ganglia function.
Safest location for a intragluteal injection?
Superolateral region - avoids the sciatic nerve and the superior gluteal nerve
Complications of ankylosing spondylitis (3)
- Limited chest expansion
- Ascending aortitis
- Uveitis
Compliment deficiency in SLE
Decrease in C3, C4, CH50
Mechanism of C. perfringens necrosis
Lecithiniase/alpha-toxin/Phospholipase C
splits phospholipid molecules resulting in membrane destruction, cell death, hemolysis and necrosis
HLA-B27 is what class of HLA (I vs II)?
Class I serotype - present on all nucleated cells
DDx: back pain + elevated alkaline phosphatase = (2)
- Osteoblast metastasis
- Paget’s disease of bone
anti-histidyl-tRNA transferase autoantibody =
Anti-Jo-1 antibody
polymyositis/dermatomyositis
bony deformities + hyperthyroidism + unilateral, large, irregular pigmented macules =
McClune Albright Syndrome
Definition - heteroplasmy
Coexistence of both mutated and wild type versions of mitochondrial genomes in one cell
Lactic acidosis + Histological ragged red fibers =
Mitochondrial myopathy
Bugs that cause necrotizing fascitis (3)
- Strep pyogenes (Group A Strep)
- Staph aureus
- Clostridium perfringens
What is a “contracture” of a wound?
excessive metalloprotease (MMP) activity that results in excessive wound contraction
Muscle involved in the valsalva maneuver that develops the elevated intra-abdominal and intra-thoracic pressure =
Rectus muscle
Differences in stature in achondroplasia vs GH/IGF-1 deficiency
Achondroplasia = short, thick appendicular skeleton with a normal axial skeleton - disproportional short stature
GH/IGF-1 deficiency = proportional short stature
Tendons that line the anatomical snuff box (3)
- Tendon of the extensor pollicis longus - medial border
- Tendon of the abductor pollicis longus - lateral border
- Tendon of the extensor pollicis brevis - lateral border
What kind of damage does UV light do to DNA?
pyrimidine dimers
What childhood exanthem has a maculopapular rash that begins on the face and quickly spreads down to extremities and trunk with co-presenting post-auricular and occipital lymphadenopathy
Rubella (part of the Togavirus family)
Intellectual disability + Gait/Posture disturbances + Eczema + Musty body odor =
Phenylketonuria (autosomal recessive)
What hormone is responsible for male pattern baldness?
DHT
“androgenic allopecia”
What causes the skin retraction seen in invasive breast cancer?
Infiltration of the suspensory Cooper ligament
What causes the peau d’orange appearance in invasive breast cancer?
Blockage of lymphatic drainage
Chronic glucocorticoid use to treat atopic dermatitis results in what (negative) side effect?
atrophy of the dermis caused by decreased ECM collagen and GAG production
First line treatment for someone having a gouty arthritis attack?
NSAIDs
Artery damaged during displacement of the femoral neck?
medial circumflex artery
How do you measure potency of an inhaled anesthetic?
MAC = minimal alveolar concentration
Inversely proportional to potency:
- low MAC
- increased potency
elderly patient + pulmonary TB + isoniazid treatment = peripheral neuropathy
Why?
Vitamin B6 deficiency caused by isoniazid use.
Requires pyridoxine supplementation.
Older patient + new back pain + recent/treated Staph bacteremia infection + fever + fatigue + malaise =
How to dx?
Vertebral osteomyelitis - probably from the Staph infection
to dx = MRI of the spine
Child with sickle cell disease + fever + pain in foot + leukocytosis =
Osteomyelitis (Salmonella typhi)
Avascular necrosis would present as bone pain only
40 year old African American woman, fever, malaise, bilateral hilar adenopathy, erythema nodosum, elevated serum Ca =
Sarcoidosis (African american woman + hilar adenopathy)
Elevated level of 1,25 dihydroxycholecalciferol (active vitamin D due to the presence of alpha1 hydroxylase in the epithelioid macrophages)
7 causes of erythema nodosum
- Sarcoidosis
- Coccidiomycoses
- Histoplasmosis
- TB
- Leprosy
- Strep infections
- Inflammatory Bowel Disease
Male newborn with macrocephaly + poor skull mineralization + misshapen long bones + fractures that occurred during birth =
Osteogenesis imperfecta - decreased collagen type I production
Hyperreflexia is seen in a lesion of the UMN or LMN?
UMN lesion leads to hyperreflexia
What childhood exanthem has a rash that begins at the head and travels downward but is preceded by cough + conjunctivitis + spots in the mouth?
Measles (part of the Paramyxovirus family)
“trabecular thinning of bone”
Osteoporosis
“persistence of primary unmineralized spongiosa in the medullary canals”
Osteopetrosis
6 P’s of lichen planus =
Purple Puritic Polygonal Planar Papules Pustules
3 arm nerves that are flexors =
Musculocutaneous (C5-C7)
Median (C5-T1)
Ulnar (C8-T1)
2 arm nerves that are extensors =
Axillary (C5-C6)
Radial (C5-T1)
Lab values (serum Ca, PTH, PO4)
Osteoporosis =
Paget’s disease of the bone =
Osteopetrosis =
All normal!
Paget’s disease will have increased ALP due to last stage being osteoblast-heavy
Weakness in hands and heaviness in eyelids by the end of the day + anterior mediastinal mass
Myasthania gravis + associated thymoma or thymic hyperplasia
Diseases caused by defective DNA break repair mechanisms (6)
- Xeroderma pigmentosum
- Carcinogenesis
- Hereditary nonpolyposis colorectal cancer (HNPCC)
- Ataxia telagiectasia
- Fanconi anemia (-> aplastic anemia)
- Bloom syndrome
Recurrent sinopulmonary infections + superficial blanching nests of distended capillaries + atrophied cerebellum + child =
Ataxia telagiectasias
superficial blanching nests of distended capillaries = telagiectasias
Rash on palms and soles and body = (4)
- N. meningitidis
- Coxsackie A
- Rocky mountain spotted fever
- Syphilis (secondary)
You drive Nice CARS with your hands and feet.
Man with an inflamed, red knee. Aspirate has crystals and increased WBC with neutrophilic predominance.
Pseudogout with Calcium pyrophosphate crystals
Cytokines important in granuloma formation = (3)
- IL-12
- IFN-gamma
- TNF-alpha
Sensory innervation of the musculocutaneous nerve
Musculocutaneous nerve (C5-C7) -> lateral cutaneous nerve of the forearm -> lateral forearm sensation
Posterior arm + Posterior forearm + Dorsal hand sensory
Posterior cutaneous branches of the radial nerve
Anterior forearm, medial forearm, and anterior arm sensation
Medial antebrachial cutaneous nerve - branch off the median cord of the brachial plexus
Trendelenburg gait - damage to inferior or superior gluteal n?
Superior gluteal nerve - gluteus minimus, medius and tensor fascia latae muscle
Difficulty rising from seated and difficulty climbing stairs - damage to inferior or superior gluteal n?
Inferior gluteal nerve - gluteus maximus muscle
Asteroid body is found in
Sarcoidosis
Main cell type in the pathology of polymyositis.
Where is the inflammation located?
CD4 T cells -> endomyseal inflammation
Main cell type in the pathology of dermatomyositis.
Where is the inflammation located?
CD8 T cells -> perimyseal inflammation
2 mechanisms of albinism:
- Decreased tyrosinase activity
- Defective tyrosine transport
Overall, decreased melanin synthesis
Autoimmune destruction of melanocytes
Vitligo
Type of gland: Salivary = Sweat glands = Mammary gland = Sebaceous gland = Meibomian gland (eyelid) =
- Salivary = merocrine
- Sweat glands = merocrine
- Mammary gland = apocrine
- Sebaceous gland = holocrine
- Meibomian gland (eyelid) = holocrine
Mutation in xeroderma pigmentosum
Defective UV-specific endonuclease
Twisted ankle inwards + pain and ecchymoses on anterolateral ankle + can still walk unassisted =
Tear of the anterior talofibular ligament
two locations of collagen synthesis
- RER of fibroblasts
- ECM
Serum _ measures osteoblast activity
ALP
Urinary _ measures osteoclast activity
Deoxypyridinoline
Family history of hypermobile joints + susceptible to easy bruising + hyperelastic skin
Ehlers-Danlos Syndrome
Cytokine responsible for keloid production/growth
TGF-beta
Hartnup disease treatment
Niacin
Most of the symptoms are due to tryptophan deficiency (-> niacin deficiency)
Positive lepromin skin test indicates a cell response with b (3) cytokines and a c bacterial load.
a=Th1
b=IL-2, IFN-gamma, IL-12
c=low
Negative lepromin skin test indicates a cell response with b (3) cytokines and a c bacterial load.
a=Th2
b=IL-4, IL-5, IL-10
c=high
Latissimus dorsi does medial/lateral rotation of the humerus. Innervated by _.
Medial rotation of the humerus
Innervated by thoracodorsal nerve (T7-T12)
Metastases to bone - osteoblastic/sclerotic (3)
- Prostate
- Small cell lung
- Hodgkin lymphoma
Metastases to bone - osteolytic (5)
- Multiple myeloma
- Non-small cell lung
- Non-hodgkin lymphoma
- Melanoma
- Renal cell carcinoma
Metastases to bone - both osteoblastic and osteolytic (2)
- GI
- Breast
What bone tumor:
- elevation of the periosteium
- may be associated with other familial cancers
- bimodal age distribution
Osteosarcoma
- Codman’s triangle - elevation of the periosteium due to the tumor being located on the edge
- Sunburst pattern on xray
- Associated with Rb/Li Fraumeni
- Occurs in young and elderly
What bone tumor is associated with t(11;22)
Ewing Sarcoma
- occurs in boys less than 15 yo
- diaphysis of bone
- onion skin periosteal reaction
- small blue cell malignant tumor
What bone tumor has bone pain that resolves with aspirin use and is found on the diaphysis?
Osteoid osteoma
What bone tumor has pain that does not resolve with aspirin use and is found in the vertebrae.
Osteoblastoma
Young boy with frequent fractures from minimal trauma + anemia + target RBCs
Osteopetrosis - defective osteoclasts
Mutation may be in carbonic anhydrase II therefore impairing the ability of osteoclasts to generate the acidic environment needed
Sawtooth infiltrate of lymphocytes at the dermal-epidermal junction
Lichen planus
Associated with HepC
54 year old woman with a past history of radical mastectomy and chronic lymphedema. Presents with multiple violaceous nodules on her arm.
Cutaneous angiosarcoma
- CD31+
- infiltration of the dermis with slit-like abnormal vascular spaces
- vascular tumor that commonly arises post-chronic lymphedema
Procollagen peptidase action in collagen synthesis
Cleavage of disulfide-rich terminal regions of procollagen
Occurs in the ECM
This is inhibited in EDS
Irritant found in poison ivy, poison oak, poison sumac
Urushiol
Cell type responsible for linear growth
Chondrocytes - produces the cartilaginous matrix in the physis/growth plate
“Endochondrial ossification”
-controlled by FGF3
Urticaria on light microscopy
Dermal edema caused by increased vascular permeability
RA can involve what part of the vertebral column?
Cervical spine
Reactive arthritis follows what 2 types of infections?
- Genitourinary or Enteritis (GI)
- Clinical manifestations are due to immune complexes that form involving bacterial antigens (even though the joint aspirates are sterile)
Genetics of achondroplasia
AD
Gain of function mutation in FGF Receptor 3
Associated with advanced paternal age
What substance is responsible for increasing the reaction rate in skeletal muscle contraction?
Calcium
Stimulates phosphorylase kinase -> activates glycogen phosphorylase-a by phosphorylating it -> turns glycogen into G1P -> ATP!
Causes of bilateral carpal tunnel syndrome (5)
- Pregnancy - fluid accumulation
- Hypothyroidism - glycosaminoglycan build up
- Diabetes Mellitus - connective tissue thickening
- Rheumatoid Arthritis - tendon inflammation
- Chronic hemodialysis - beta-2 microglobulin deposition
These are types of _
- superficial spreading
- nodular
- lentigo maligna
- acral lentiginous
melanoma
Rheumatoid factor is _
IgM autoantibody that targets the Fc portion of IgG
what effect does osteoporosis have on osteoclast activity, RANK L concentration and osteoblast concentration?
Low estrogen -> osteoporosis
low estrogen ->
- increases osteoclast activity
- increases RANK-L concentration
- decreases osteoblast concentration due to increasing turn over
Osteomalacia cause?
Caused by decreased vitamin D
diabetic neuropathy pain?
burning pain
What tumor is often associated with Paget’s disease of the bone?
Osteosarcoma
Globus sensation/hystericus/pharyngeus
Abnormal sensation of a foreign body/tightness in the throat
Worse when swallowing saliva, alleviated when swallowing food or liquid
Functional disorder
Removing _ from ECF will cause cadherins to dissociate
Calcium
Cadherins are calcium-dependent
(cell)-cadherin-cadherin-(transmembrane protein-filament)
Posteriorly dislocated tibia most commonly injures the _
Popliteal artery
-It is located deep within the popliteal fossa and is susceptible to tearing by traction (anterior or posterior dislocation)
(anterior)-bones-popliteal artery-popliteal vein-tibial nerve-(posterior)
Patient had a chest tube put in and now she cannot raise her R arm above her head and when pushing against a wall, the R scapula protrudes. What nerve and muscle?
Long thoracic nerve is damaged resulting in damage to serratus anterior
Articular cartilage is made of
Type II collagen
Also made of type II collagen = all other cartilage, vitreous body, nucleus pulposus
Red safranin O stain, stains what 3 things red
- Cartilage
- Mast cell granules
- Mucin
What is the lens made out of?
Type IV collagen
Also made of type IV collagen = basement membrane, basal lamina
What is the only unmyelinated efferent nerve?
Autonomic postganglionic nerve
Other group C nerves:
- Afferent neurons that conduct heat, slow onset dull burning/visceral pain
- Primary bipolar sensory neurons
