Rheumatology, Dermatology, MSK Flashcards Preview

USMLE World Missed Questions > Rheumatology, Dermatology, MSK > Flashcards

Flashcards in Rheumatology, Dermatology, MSK Deck (269):

What is essential for the formation and differentiation of osteoclasts?

The RANK receptor/ RANK ligand interaction


What results from overexpression of RANK receptors in hypoestrogenic states?

Increased bone resorption due to increased osteoclastic activity.


What is heteroplasmy?

The condition of having different mitochondrial organellar genomes (mutated and wild type) within a single cell.


Name the three classes of drugs used to treat acute gouty arthritis and which of these treatments is first line.

Colchicine, NSAIDs, glucocorticoids. NSAIDs are first line.


What is the mechanism of action of colchicine?

Treats acute gouty arthritis by binding the intracellular protein tubulin and inhibiting its polymerization into microtubules (cytoskeletal elements).


What toxicites are associated with colchicine use?

GI toxicity (diarrhea), nausea, abdominal pain. Should be avoided in patients who are elderly or who have renal dysfunction.


What is the function of MMP (matrix metalloproteinases) in wound healing?

Encourages myofibroblast accumulation at the wound edges and scar tissue remodelling. Myofibroblasts then initiate wound contraction during healing by second intention.


When do contractures occur in wound healing?

When unusually pronounced MMP activity results in excessive wound contraction. Contractures cause wound deformities.


What type of bone is most commonly affected in postmenopausal osteoperosis and where is this bone present?

Cancellous bone; predominantely present in the vertebral column, distal radius, hip, and neck of the femur.


What effect does primary osteoperosis have on serum calcium, phosphorous, and PTH levels?

Normal calcium, phosphorus, and PTH


What is the first line treatment for disease modification in patients with moderate to severe RA?

Methotrexate (can be combined with Leflunomide and TNF1 inhibitors if no response with MTX alone)


What are the side effects of methotrexate?

Stomatitis (mouth ulcers), hepatotoxicity (abnormal LFTs), myelosuppression. Folic acid supplementation reduces stomatitis.


What is hydroxychloroquine used to treat?

SLE or early mild seronegative rheumatoid arthritis.


What is a potentially serious effect of hydroxychloroquine use?

Permanent retinal damage.


Where does the Posterior Cruciate ligamant originate and insert?

Originates from the anterolateral surface of the medial femoral condyle and inserts into the posterior intercondylar area of the tibia.


How are osteocytes connected to each other?

By gap junctions.


How do osteocytes exchange nutrients/ waste products and send signals to each other?

Through gap junctions.


What is the function of osteocytes?

To maintain the structure of mineralized matrix and to control the short term release and deposition of calcium (calcium homeostasis).


What osteocyte cell structures are used to send signals/ exchange information between osteocytes?

Long intracanalicular processes that extend through the ossified bone matrix.


What comorbid condition is present in the majority of patients with myasthenia gravis?

Thymoma or thymic hyperplasia


From what embryologic structure is the thymus derived?

Third pharyngeal pouch


From what embryologic structure are the inferior parathyroid glands derived?

Third pharyngeal pouch.


What is derived from the first pharyngeal pouch?

Epithelium of middle ear and auditory tube


What is derived from the second pharyngeal pouch?

The epithelium of the palatine tonsil crypts


What is derived from the third pharyngeal pouch?

Thymus, inferior parathyroid glands.


What is derived from the fourth pharyngeal pouch?

Superior parathyroid glands, ultimobranchial body.


What is derived from the first pharyngeal membrane?

Tympanic membrane


What is derived from the first pharyngeal groove?

Epithelium of the external ear canal.


What symptoms are associated with damage to the musculocutaneous nerve?

Loss of innervation of the upper arm flexors (biceps brachii, coracobrachialis, brachialis) and lack of sensory information to the skin of the lateral forearm


From what nerve roots does the musculocutaneous nerve arise?

C5-C7 rami; upper trunk of the brachial plexus.


What types of injuries may cause musculocutaneous nerve damage?

Forceful injuries that cause separation of the neck and shoulder.


What is the most common presentation of tinea corporis?

An annular scaling plaque with well demarcated, raised erythematous borders and central clearing.


What drug is commonly used to treat dermatophytosis and what drug class is it in?

Terbinafine, allylamines class


What is the mechanism of action of Terbinafine?

Inhibition of synthesis of ergosterol of the fungal membrane by inhibiting the enzyme squalene epoxidase.


What are bacterioid species?

Gram negative anaerobic rods that produce beta lactamase


What is Piperacillin-tazobactam used to treat?

Combination of extended spectrum penicillin with a beta lactamase inhibitor. Effective against gram negative enteric rods including Pseudomonas a. and Bacteroides fragilis.


Pending lab results for septic arthritis, what drug should be prophylactically given and what condition is it used to treat?

Ceftriaxone to treat gonococcal arthritis.


What symptoms are characterized by the term Eczematous dermatitis?

Erythematous, papulovesicular, weeping, encrusted lesions that may evolve into thickened scaly plaques.


What five conditions are characterized by the term Eczematous dermatits?

Allergic contact dermatitis, atopic dermatitis, drug related eczematous dermatitis, photo eczematous dermatitis, primary irritant dermatitis.


Describe the immunologic process associated with allergic contact dermatitis.

Antigens at the epidermal surface are selected by Langerhans cells and carried to draining lymph nodes where they are presented by Langerhans cells to CD4 T cells. The T cells migrate to the skin and incite an inflammatory response within 24 hours of antigen re-exposure.


What is spongiosis histologically?

Epidermal accumulation of edematous fluid in the intercellular spaces.


What condition is characterized by spongiosis?

Acute eczematous dermatitis (contact dermatitis).


What factor is responsible for up to 80% of the variation in peak bone mass among individuals?

Genetic factors.


Name five side effects of thiazide diuretics.

Increased urinary excretion of K+ and H+ (hypokalemia and metabolic alkalosis), hyponatremia, hyperuricemia (uric acid reabsorption), hyperlipidemia, decreased insulin secretion and glucose uptake- hyperglycemia


What findings are characteristic of hypokalemia?

Muscle weakness/ paralysis, Prominent U waves on EKG


Name a drug that both decreases bone fracture and breast cancer risk.



What type of drug is Raloxifene?

Selective estrogen receptor modulator (SERM); binds to estrogen receptors and exhibits tissue specific behaviour that either imitates or antagonizes the natural effects of estrogen.


How does Raloxifene act on bone?

As an estrogen agonist to inhibit osteoperosis


How does Raloxifene act on mammary tissue?

As an estrogen receptor antagonist to provide protection against estrogen receptor positive breast cancer.


What type of injury typically characterizes a lunate dislocation?

Fall on an outstretched, dorsiflexed hand.


What is the relationship of the lunate bone to the scaphoid bone?

Lunate bone is directly medial (i.e. towards the pinky) to the scaphoid bone.


What three structures pass through the popliteal fossa?

Tibial nerve, popliteal vein, popliteal artery.


What muscles are innervated by the tibial nerve?

Gastrocnemius, soleus, plantaris muscles; all responsible for plantar flexion of the foot; flexor digitorum and hallucis longus- responsible for toe flexion, and tibialias posterior muscle responsible for inversion of foot.


In a patient with a tibial nerve injury, what is the position of their lower extremity?

Dorsiflexed and everted foot.


What sensory innervation is lost in tibial nerve injury?

Sensory loss to the distal plantar surface of the foot (skin of the sole of the foot).


What histologically characterizes urticaria?

Superficial dermal edema and lymphatic channel dilation. No epidermal changes are present.


Describe Lichen planus.

Polygonal, planar, pruritic, purplish plaques on the wrists, hands, trunk, and legs.


Describe the muscular changes occuring in the eye during acommodation.

When the eye focuses on a near object, contraction of the cilliary muscles causes relaxation of the zonular fibers allowing the lens to relax and assume a more convex shape.


What happens to the ciliary muscle when looking at a distant object?

It relaxes and the lens flattens due to outward radial tension exerted by the zonular fibers.


What physiological changes cause presbyopia?

Decreased lens elasticity, changes in lens curvature, diminished strength of the ciliary muscle.


What characterizes aging of the skin?

Thinning of the dermis and epidermis with flattening of the dermoepidermal junction, decreased numbers of fibroblasts, reduced synthesis and breakdown of collagen and elastin fibers.


What type of crystals are diagnostic for acute gouty arthritis?

Negatively bifringent crystals.


What is the mechanism of action of colchicine?

An anti-inflammatory drug that acts by binding to the intracellular protein tubulin and preventing tubulin polymerization into microtubules. This leads to impaired leukocyte migration and phagocytosis.


What is the most common defect associated with achondroplasia?

Activating mutation of the fibroblast growth factor receptor-3 at the epiphyseal growth plate which inhibits growth of the plate.


What is characteristic of bone length in patients with achondroplasia?

Short, thick tubular long bones in the appendicular skeleton and normal axial (spine length)


What are the layers in order from middle to end of young long bones?

Diaphysis, metaphysis, epiphyseal cartilage, epiphysis.


What is the typical presentation of a patient with Paget's disease of the bone?

An older patient with increased alkaline phosphatase levels


Describe the disease process of Paget's disease of the bone.

Marked osteoclastic activation is followed by an increase in osteoblasts. This causes increased bone resorption and formation of abnormal bone. New collagen is laid down haphazardly causing a mosaic pattern of lamellar bone with irregular sections linked by cement lines (representing previous areas of bone resorption).


What symptoms are consistent with congenital hypothyroidism?

Neonates that appear lethargic, that feed poorly, that exhibit prolonged jaundice, and that demonstrate constipation, muscle hypotonia, and a hoarse cry. Patient has pale, cole, dry skin, mysedema, and macroglossia. Coarse facial features and umbillical hernia are also commonly present.


What comorbid conditions do infants with congenital hypothyroidism have increased risk for?

Congenital heart defects such as ASDs and VSDs.


How does Malassezia furfur appear on light microscopy?

Spaghetti and meatballs appearance with spores and hyphae (with short cigar butt appearance)


What inflammatory mediators are produced in psoriasis?

Th1 and Th17 cytokines, TNFa, IFNy, IL-23, IL-17 and keratinocyte growth factors leading to keratinocyte proliferation, inflammation, and angiogenesis.


How do topical vitamin D analogs work in the treatment of psoriasis?

By binding to and activating the vitamin D receptor, a nuclear transcription factor that causes inhibition of keratinocyte proliferation and stimulation of keratinocyte differentiation. It also inhibits T cell proliferation and other inflammatory mediators.


Name three topical vitamin D analogs used in the treatment of psoriasis.

Calcipotriene, calcitrol, tacalcitol.


What is the mechanism of action of etanercept?

Recombinant form of the TNF receptor that binds TNFa; it is used to treat moderate to severe plaque type psoriasis.


What organism causes over 95% of gas gangrene?

Clostridum perfringens.


What conditions are caused by clostridum perfringens?

Gas gangrene and toxin mediated, late onset food posioning characterized by transient watery diarrhea


During what type of surgical procedure is the long thoracic nerve often injured?

During axillary lymph node dissections as may occur during radical mastectomy.


To what drug class does nafcillin belong?

Penicillinase-resistant penicillins


What is nafcillin most commonly used to treat?

Empirical treatment of skin and soft tissue infections due to S. aureus


What is caudal regression syndrome?

A rare condition where patients are born with agenesis of the sacrum and occasionally the lumbar spine. They experience flaccid paralysis of the legs, dorsiflexed contractures of the feet, and urinary incontinence.


What condition is related to caudal regression syndrome?

Poorly controlled maternal diabetes.


What is necessary for nucleoside analog antiviral drugs to function?

They must be phosphorylated into nucleotides to function and require viral phosphorylating enzymes.


Name four nucleoside analog drugs.

Acyclovir, valacyclovir, famciclovir, ganciclovir.


The absence of viral thymidine kinase in a herpesvirus strain confers resistance to what class of drugs?

Nucleoside analog antiviral drugs.


Thymidine kinase deficient (and acyclovir-resistant) varicella zoster virus isolates are obtained from what type of patient?

AIDS patients exclusively.


In an AIDS patient with herpes zoster, what drugs are used to treat the condition?

Foscarnet or cidofovir


How is cidofovir activated?

It is a nucleoside monophosphate (nucleotide) that requires only cellular kinases for activation


What part of the sarcomere is composed exclusively of myosin thick filaments?

The H band (part of the A band on either side of the M line)


What happens when a tRNA is mischarged with the incorrect amino acid (and is not corrected by proofreading)?

It will be incorporated into the growing polypeptide chain.


Chronic corticosteroid therapy for atopic eczematous dermatitis causes what condition?

Decreased production of extracellular matrix collagen and glycosaminoglycans causing atrophy of the dermis with loss of dermal collagen, cracking, drying, and or tightening of the skin. Telangiectasias, ecchymoses, and atrophic striae may also be found.


What is the most common complication associated with a varicella zoster virus infection?

Post herpetic neuralgia lasting for more than one month after an erruption.


What conditions may be caused by Bartonella henselae?

Cat scratch disease, bacillary angiomatosis in immunocompromised patients, culture negative endocarditis.


How does bacillary angiomatosis present?

As red-purple papular skin lesions


What is the virulence factor of staph a.?

Protein A; it forms part of the outer peptidoglycan layer of S. aureus and binds with the Fc portion of IgG antibodies at the complement binding site, preventing complement activation. This causes decreased production of C3b, leading to impaired opsonization and phagocytosis.


What causes gout?

Deposition of monosodium urate crystals


What is the function of Phosphoribosyl pyrophosphate (PRPP) synthetase?

Enzyme responsible for production of the activated ribose necessary for de novo synthesis of purine and pyrimidine nucleotides.


Describe the inflammatory process associated with gout.

Phagocytosis of urate crystals by neutrophils causes release of cytokines and inflammatory mediators which leads to further neutrophil activation and chemotaxis. This causes a positive feedback loop which amplifies the inflammatory response.


Where is procollagen synthesized?

Within the endoplasmic reticulum


Where is procollagen converted to tropocollagen?

The extracellular space.


What is the typical presentation of a patient with Lambert-Eaton myasthenic syndrome?

Proximal muscle weakness, gait alteration, difficulty arising from a chair, difficulty climbing stairs. Often patients have cranial nerve involvement (diplopia, ptosis, dysarthria, dysphagia, etc)


What is the pathophysiology of Lambert Eaton myasthenic syndrome?

Antibodies directed against voltage gated calcium channels that participate in Ach release. Half of all patients with this condition also have a malignancy (small cell lung cancer classically).


Children with what condition benefit from administration of vitamin A?

Children with measles


What symptoms are associated with CREST syndrome?

Calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, teleangiectasias


What antibodies are specific for CREST syndrome?

Anti-centromere antibodies.


What antibodies are specific for systemic sclerosis (diffuse scleroderma)?

Anti-DNA topoisomerase I (Scl-70) antibodies.


In what condition are anti-histone antibodies found?

Drug induced SLE.


In what conditions are anti-phospholipid antibodies found?

In patients with SLE and in antiphospholipid antibody syndrome.


What is innervated by the deep peroneal nerve?

The extensor and great dorsiflexors.


What nerve is most susceptible to damage due to compression or leg fracture?

Common peroneal


What symptoms result from injury to the common peroneal nerve?

Foot drop


Damage to the tibial nerve would cause what motor symptoms?

Difficulty with plantar flexion.


Sunlight exposure catalyzes what reaction in vitamin D synthesis?

7-dehydrocholesterol --> cholecalciferol (Vitamin D3)


What is the pathophysiology associated with Myasthenia gravis?

Autoantibodies against postsynaptic nicotinic acetylcholine receptors. This causes decreased ability of Ach to bind and open postsynaptic cation channels, decreasing end plate potential and preventing formation of muscular action potentials.


What class of drugs are used to treat myasthenia gravis?

Cholinesterase inhibitors


What is the mechanism of action of Scopolamine?

Selective muscarninc Ach receptor antagonist that will reduce the effects of cholinesterase inhibitors in sites where Ach action is mediated by muscarinic receptors. It does not affect nicotinic receptors in skeletal muscle


What is the mechanism of action of Pilocarpine?

Nonselective muscarinic receptor agonist.


What are the two subtypes of anorexia nervosa?

Restricting and binge eating// purging


What is the key clinical difference between diagnosis of bulemia vs anorexia nervosa?

Bulimic patients maintain their body weight at or above a minimally normal level.


What is needed for diagnosis of major depressive disorder?

5 of the following symptoms for at least 2 weeks (which must include depressed mood or anhedonia): Sleep disorder, Interest deficit, Guilt, Energy deficit, Concentration deficit, Appetite disorder, Psychomotor retardation or agitation, Suicidality (SIGECAPS)


What is dysthymic disorder?

A chronic, low intensity mood disorder that responds well to antidepressant medications. Its symptoms are less severe than major depressive disorder but they must be present for at least two years for diagnosis to be made.


What is needed for diagnosis of dysthymic disorder?

Depressed mood occurring most days for at least two years and presence of at least two of the following: poor appetite or overeating, insomnia or hypersomnia, low energy/ fatigue, low self esteem, poor concentration/ difficulty making decisions, feelings of hopelessness.


What is the most commonly dislocated joint in the body?

The glenohumeral joint; anterior dislocations are most common


What type of injury causes anterior dislocation of the humerus?

Injuries involving forceful external rotation and abduction of the arm at the shoulder.


What physical symptoms are present with anterior dislocation of the humerus?

Flattening of the deltoid muscle, axillary nerve damage (deltoid and teres minor muscle weakness), decreased sensory innervation to the lateral arm and skin over the deltoid.


What is the mechanism of inheritance of androgenetic alopecia?

Polygenetic inheritance with variable penetrance.


How does a benign glomus tumor (glomangioma) present?

As a very tender, small red-blue lesion under the nail bed.


From what cell origin do glomus tumor cells arise?

Modified smooth muscle cells that control thermoregulation of the dermal glomus bodies.


What is the differential diagnosis for a bluish neoplasm occuring beneath the nail bed?

Glomus tumor (glomangioma)- benign or subungual melanoma.


What are glomus bodies?

Small encapsulated neovascular organs found in the dermis of the nail bed, the pads of the fingers and toes, and the ears. They are composed of a rich blood supply and their role is to shunt blood away from the skin surface in cold temperatures to prevent heat loss and to direct blood flow to the skin surface in hot environments to facilitate heat dissipation.


Spontaneous, episodic deviations of the head to the right side accompanied by muscle pain in the neck which can be suppressed manually is characterized as what condition?



What is dystonia?

Sustained, involuntary muscle contractions which force parts of the body into sustained, abnormal and sometimes painful positions. They may be idiopathic or due to impaired function of the basal ganglia.


What are the most common types of dystonia?

Cervical dystonia or spasmodic torticollis- It is a focal dystonia is the most common. Also common are blepharospasm (closing of the eyelids) and writer's cramp.


What is myoclonus?

A sudden brief shock like contraction (ex. hypnic jerks when falling asleep, hiccups, etc.).


Injury to the lower trunk of the brachial plexus causes what symptoms?

Hand weakness, clumsiness, paralysis due to damage to all intrinsic muscles of the hand.


What nerves and nerve roots contribute to the lower trunk of the brachial plexus?

C8 and T1; median and ulnar nerves.


What are the adverse effects associated with succinylcholine?

Malignant hyperthermia (especially with halothane), severe hyperkalemia in patients with burns, myopathies, crush injuries, and denervation, and bradycardia from parasympathetic stimulation of tachycardia from sympathetic ganglionic effects.


What is the mechanism of action of succinylcholine?

Depolarizing NMJ blocking agent that attaches to the nicotinic acetylcholine receptor and depolarizes the neuromuscular end plate. It is not degraded by acetylcholinesterases causing continuous stimulation of the endplate (transient fasciculations)


What type of paralysis is caused by succinylcholine?

Flaccid paralysis due to desensitized nicotinic acetylcholine receptors. This is a phase II block.


What ions does succinylcholine mediate?

Sodium influx and potassium release which may cause hyperkalemia and arrythmias


In patients with crush/ burn injuries, denervating fiseases, and myopathies, what agents are preferred over administration of succinylcholine?

Vecuronium or rocuronium; They are non-depolarizing agents.


What four elements underly the pathophysiology of acne?

1. Follicular epidermal hyperproliferation; 2. Excess sebum production; 3. inflammation; 4. propionibacterium acnes


What drugs are known to cause acneiform eruptions?

Anabolic steroids (eg methyltestosterone), epidermal growth factor receptor inhibitors, lithium.


Clinical manifestations of leprosy vary widely based upon what factor?

The strength of the Th1 cell mediated immune response to the organism.


What are the symptoms of tuberculoid leprosy?

Localized inflammation which damages the skin and cutaneous nerves and that causes small hypopigmented, well demarcated plaques with decreased sensation. They have a milder response due to high Th1 mediated response which activates macrophages to kill M leprae organisms.


What is lepromatous leprosy?

Disseminated disease characterized by an innate inability to mount a cellular response against M leprae. Patients develop numerous poorly demarcated plaques that are widespread. Over time leonine facies and degeneration and loss of the nose and digits occurs.


What is seen in infected tissues of a patient with lepromatous leprosy?

Extensive accumulation of acid fast bacilli within macrophages and a Th2 cytokine profile (IL-4, IL-5, IL-10)


What can distinguish between tuberculoid and lepromatous leprosy?

Lepromin skin test (tuberculoid patients develop an indurated nodule much like a positive PPD due to a strong CD4+ Th1 cell mediated response). It is nonreactive in lepromatous cases.


Where are COX-2 levels detected?

Normally undetectable but can be seen where inflammatory cells are activated


What drug is ideal for treatment of CHF/ hypertension in a patient at risk for osteoporosis?



From where does the femoral head and neck derive their blood supply?

Superior and inferior gluteal arteries and medial and lateral femoral circumflex arteries. Together they form the trochanteric anastomosis.


What artery makes the greatest contribution to the blood supply of the femoral neck and is vulnerable to damage from femoral neck fractures?

Medial femoral circumflex artery. May cause avascular necrosis of the femoral head.


Drugs with what type of metabolism are linked to drug induced lupus?

Drugs metabolized by N-acetylation in the liver.


Name two drugs that cause drug induced SLE.

Hydralazine, procainamide.


What is the function of dystrophin?

Allows interaction between extracellular connective tissue and the intracellular connection apparatus. Deletion of this gene causes DMD.


What findings are characteristic of shaken baby syndrome?

Subdural hematoma with bilateral retinal hemorrhages in an infant.


Colchicine binding to microtubules to prevent their aggregation results in what therepeutic effect?

Disrupts membrane dependent functions such as chemotaxis and phagocytosis. It also reduces formation of leukotriene B4


When are glucocorticoids used in the treatment of RA?

To produce quick symptomatic relief; used in short term therapy only.


On electron micrograph of striated muscle sarcomeres, where can actin filaments be found?

In the Z line, in the center of the lucent region (I band)


In a muscle sarcomere, to what do actin and myosin bind respectively?

Actin in the I band attaches at the Z-line; Myosin in the H band attaches to the M line.


In what conditions can lipid accumulation in the muscle fibers be seen?

Lipid myopathies such as carnitine palmitoyltransferase deficiency


Describe the muscle findings in a patient with DMD.

Muscle fibers are replaced by fat and connective tissue, causing pseudohypertrophy.


What is one of the primary functions of type I collagen?

Bone matrix formation; it gives bones flexibility


How is osteogenesis imperfecta most commonly transmitted?

Autosomal dominant inheritance.


What organ systems may be affected by ankylosing spondylitis?

MSK- peripheral enthesitis (inflammation at the site of tendon insertion into the bone); Respiratory- enthesopathies of the costovertebral/ costosternal junctions may limit chest wall and expansion causing hypoventillation; CV- ascending aortitis and aortic insufficiency; Eyes- anterior uveitis (pain, blurred vision, photophobia, conjunctival erythema)


What is haptoglobin?

A plasma protein that binds free hemoglobin to prevent its renal excretion.


What is characteristic of haptoglobin levels in patients with hemolytic anemias?

Levels are decreased as haptoglobin-hemoglobin complexes have a half life of 90 minutes. In hemolysis, haptoglobin binds to free hemoglobin and the complex is hepatically cleared.


What are the most common benign vascular tumors in adults?

Cherry hemangiomas (or cherry angiomas) . They are always cutaneous and are not found in the mucosa or deep tissues.


What is a strawberry hemangioma?

Infantile/capillary hemangiomas that appear during the first weeks of life and grow rapidly. They frequently regress spontaneously by 5-8 years of age.


Describe the presentation of Paget's disease of the bone.

Older men with pain and deformity in a bony area and hearing loss


What is the pathology associated with Paget's disease of the bone?

Excessive osteoClastic bone resorption. Markedly increased bone turnover causes chaotic bone formation.


What regulates the function of osteoclasts?

Systemic hormones, locally acting cytokines


What are the factors that contribute to osteoclastic differentiation?

Produced by the osteoblast; they are M-CSF (macrophage colony stimulating factor) and RANK-L


What class of drugs can be used to treat male pattern baldness? Give the most commonly prescribed drug.

Androgen antagonists- 5a reductase inhibitors. Finasteride is most prescribed.


What is Terbinafine used to treat?

Squalene epoxidase inhibitor (oral anti fungal) used to treat tinea capitis.


From what nerve roots does the obturator nerve arise?

Nerve roots L2-L4.


From what nerve roots does the femoral nerve arise?



From what nerve roots does the common peroneal nerve arise?



From what nerve roots does the tibial nerve arise?



From what nerve roots does the superior gluteal nerve arise?



From what nerve roots does the inferior gluteal nerve arise?



How is the obturator nerve most often injured?

Anterior hip dislocation, iatrogenic


What motor deficit is associated with obturator nerve injury?

Thigh adduction


How is the femoral nerve most often injured?

Pelvic fracture or mass involving iliopsoas/ iliacus muscle (hematoma, abcess, etc)


What motor deficit is associated with femoral nerve injury?

Flexion of thigh, extension of leg


What motor deficit is associated with common peroneal nerve injury?

Foot eversion, dorsiflexion, toe extension


How is the common peroneal nerve most commonly injured?

Fibula neck fracture of nerve compression at fibular neck


How is the tibial nerve most commonly injured?

Trauma to the knee


What motor deficits are seen with tibial nerve damage?

Foot inversion, plantar flexion, and toe flexion


How are the superior and inferior gluteal nerves most commonly injured?

Iatrogenic (posterior hip dislocation or buttocks injection)


What motor deficits are seen with superior gluteal injury?

Thigh abduction


What motor deficits are seen with inferior gluteal injury?

Thigh extension


Describe the course of the femoral nerve

It descends through the fibers of the psoas major muscle, emerges laterally between the psoas and iliacus muscle, and runs beneath the inguinal ligament into the thigh.


Patients with femoral nerve injury complain of what types of symptoms?

Difficulty with stairs and knee buckling/ falling. Diminished patellar reflex is seen as is sensory loss over the anterior and medial thigh and medial leg


What is it called when new bullae form in a patient with PV due to gentle traction?

Nikolsky sign


Pemphigus vulgaris is an autoimmune bullous disease characterized by autoantibodies to what proteins?

Desmosomal proteins 3 and 1 (desmogliens 3 and 1)


PABA ester sunscreens absorb what type of radiation?

UVB radiation only. They do not significantly absorb or block UVA


Name two places where the ulnar nerve is most frequently injured.

Near the medial epicondyle of the humerus or in Guyon's canal near the hook of the hamate and pisiform bone in the wrist.


What are the most important functions of vitamin D?

Calcium and phosphorus absorption in the GI tract; osteoid mineralization.


Histologically, what characterizes a Vitamin D deficiency?

An increase in unmineralized osteoid matrix and widening between osteoid seams


Histologically, what characterizes osteoperosis?

Trabecular thinning with fewer interconnections.


Histologically, what characterizes osteopetrosis?

Persistence of primary, unmineralized spongiosa in the medullary canals.


What symptoms accompany parvovirus infection in adults?

Arthritis involving the proximal interphalangeal, metacarpal, knee and ankle joints. Joint involvement is usually symmetric and sx resolve spontaneously.


Foreign bodies elicit a granulomatous response. What is the clinical manifestation of this?

Tender erythematous brown or purple papule, nodule, or plaque


Microscopically, what characterizes granulomas?

Aggregates of activated macrophages forming an epithelioid appearance.


Which two muscles act as the major flexors of the hip?

Iliacus and psoas muscles


Describe the location of the psoas muscle.

It arises from the transverse processes and lateral aspects of the 12th thoracic through 5th vertebrae. It courses down across the pelvic brim anterior to the hip joint capsule and deep to the inguinal ligament. It inserts into the lesser trochanter of the femur via a tendon shared with the iliacus muscle.


What signs and symptoms accompany psoas abscess?

Fever, back/ flank pain, inguinal mass, difficulty walking Patients typically position themselves with hip flexion and lumbar lordosis to decrease discomfort.


What five classes of drugs are used to treat osteoperosis?

Estrogen, estrogen selective receptor modulators (SERMs), bisphosphonates, calcitonin, parathyroid hormone. Bisphosphonates are used most commonly.


What substances are bisphosphonates structurally similar to?

Analogues of pyrophosphate, a component of hydroxyapatite.


Name three bisphosphonates.

aledronate, risedronate, ibandronate.


What major muscles are used when sitting up?

External abdominal obliques, rectus abdominus, hip flexors (the psoas major and iliacus contribute to hip flexion)


Where does the illiopsoas insert?

Via the common iliopsoas tendon into the lesser trochanter of the femur.


What is characteristic of dermatitis herptiformis histologically?

Characterized by formation of microabcesses containing fibrin and neutrophils at the dermal papillae tips. The overlying basal cells become vacuolated and blisters form at the tips of involved papillae. Older lesions may demonstrate eosinophilic infiltration.


What is characteristic of labs in a patient with atopic dermatitis (eczema)?

High serum levels of IgE, peripheral eosinophilia, high levels of cAMP phosphodiesterase in leukocytes


What is a characteristic physical finding associated with fibromyalgia?

Multiple symmetrically distributed tender spots over the patients' muscles, joints, and tendons such as over the spine of the scapula, the lateral epicondyle, and the medial fat pad of the knee. Tenderness in eleven of eighteen predetermined painful points are required for diagnosis.


Describe the presentation of actinic keratoses.

Erythematous papules with an overlying whitish scale. They are often felt more than seen with a rough sandpaper like texture. They develop due to sun exposure and are pre-malignant lesions which rarely progress to squamous cell carcinoma.


What is pityriasis rosea?

Solitary pink or brown plaque with central clearing on the trunk, neck, or extremities followed by the development of an ovoid maculopapular rash with lesions oriented in an oblique direction along skin tensin lines on the back (xmas tree pattern)


What drugs are used to treat lyme disease?

Doxycycline or penicillin type antibiotics.


What types of bacteria is metronidazole used to treat?

Anaerobic bacteria and parasites.


What is the pathophysiology associated with vitiligo?

Complete loss of epidermal melanocytes.


In breast cancers, what causes nipple inversion and skin retraction?

Nipple inversion is caused by tumor invasion of the central region of the breast; skin retraction is caused by cancer infiltration of the suspensory Cooper ligaments.


What are the major indications for long term uric acid therapy?

Macroscopic tophaceous deposits, more than 3 episodes of gouty arthritis per year, uric acid stones, gross elevation of serum uric acid levels.


What is the best long term treatment choice for chronic tophaceous gout?



For whom are uricosuric agents helpful in the treatment of gout and for whom should they be avoided?

Helpful in patients with good renal function and who can maintain good renal flow; contraindicated in patients excreting excessive amounts of uric acid in their urine to prevent uric acid nephrolithiasis.


What are train of four responses?

Used during anesthesia to assess the degree of muscle relaxation induced by NMJ blocking agents.


During train of four responses, what is shown by depolarizing blockers?

Sustained and equal reduction of all four twitches during phase I with eventual transition to phase II with continued administration of succinylcholine.


What can reverse the paralytic action of nondepolarizing NMJ blocking drugs?

Anticholinesterase agents such as neostigmine.


How is succinylcholine affected by neostigmine?

Succinylcholine is augmented by neostigmine during phase I block but reversed by neostigmine during phase II block


Chronic lymphedema is a risk factor for the development of what condition?

Cutaneous angiosarcoma (Stewart-Treves syndrome)


What is the appearance of angiosarcoma histopathologically?

Infiltration of the dermis with slit-like abnormal vascular spaces.


What cutaneous manifestations are associated with dermatomyositis?

Grotton papules, heliotrope rash


What lab results are abnormal in patients with dermatomyositis?

Elevated CK, positive Anti-nuclear antibodies, anti-Jo1 antibodies.


What are TNF-alpha drugs used to treat?

Powerful anti-inflammatory agents with ability to improve synovitis, reduce joint erosion, and slow disease progression in patients with RA


Name three TNF-alpha inhibitors.

Infliximab, etanercept, adalimumab


What adverse effects are associated with TNF-alpha inhibitor treatment?

Infection due to inhibited macrophage functioning; reactivation of latent TB


Acid fast bacilli on sputum stain coupled with cough and hemoptysis are characteristic of what condition?



Synovial crystals that deposit in the synovium and cartilage in gout have what characteristics?

Monosodium urate crystals which appear needle shaped and negatively birefringent under polarized light.


Synovial fluid analysis of a gouty joint will show what?

Increased WBCs with a neutrophilic predominance, monosodium urate crystals under polarized light microscopy.


What does negative birefringence mean?

When crystals are aligned parallel to the slow ray of the compensator, they appear yellow; when aligned perpendicular, they are blue.


What is diagnostic of pseudogout?

Rhomboid shaped calcium pyrophosphate crystals with positive birefringence under polarized light (i.e. blue when aligned parallel; yellow when perpendicular).


What is pseudogout?

Accumulation of calcium pyrophosphate crystals in the synovial fluid. The knee is involved in more than 50% of cases of pseudogout.


Rank ecchymoses, purpurae, and petechiae in order of increasing size.

Petechiae, purpurae, ecchymoses.


From which spinal nerves does the median nerve receive its contributions?

From C6-T1 spinal nerves


Describe the path of the median nerve.

It courses with the brachial artery in the groove between the biceps brachii and the brachialis muscles and gains access to the forearm in the medial aspect of the antecubital fossa and immediately courses between the humeral and ulnar heads of the pronator teres muscle. It courses between the flexor digitorium superficialis and profundus muscles before entering the wrist.


Name the five muscles that insert on the clavicle.

Pectoralis major, deltoid, subclavius, trapezius, STM.


What mutation is seen in 40-60% of patients with melanoma?

BRAF mutation V600E (valine replaced by glutamate)


What is BRAF?

A protein kinase involved in activation of signalling pathways for melanocyte proliferation. It is seen in 40-60% of patients with melanoma.


What is Xanthelasma?

A cutaneous lesion commonly found on the eyelid that contains lipid-laden macrophages histologically. These papules are typically yellow due to location of foam cells in the superficial dermis.


In what conditions do xanthelasmas occur?

In association with primary or secondary hyperlipidemia- cholestatic conditions such as PBS are a potential cause.


Acanthosis nigricans are associated with what two conditions?

Insulin resistance and GI malignancies.


Where does osteomyelitis most commonly occur?

In the metaphysis of long bones. It occurs mostly in young boys. It occurs in the metaphysis due to slower blood flow and capillary fenestrae in this region.


Why are adults less likely to get osteomyelitis?

Due to changes within the epiphysial closure.


Describe the pathophysiology of hematogenous osteomyelitis.

It begins with a seeding event that causes acute cellulitis of the bone marrow resulting in inflammation confined within the boney space. This causes increased intramedullary pressure which compromises blood flow and forces infectious exudate through vascular channels into the cortex and periosteal region. This can cause ischemia and necrosis.


What does hematogenous osteomyelitis progress to if untreated?

Chronic suppurative osteomyelitis.


What are two other names for trabecullar bone?

Spongy or cancellous bones.


Most of the appendicular skeleton is composed of what type of bone?

Cortical bone.


Vitamin D deficiency causes what pathology in bones?

Excessive unmineralized osteoid with low mineral density.


After chickenpox, where does VZV lie dormant?

In the sensory fibers of the dorsal root ganglia of the spinal cord.


What findings are present on light microscopy of VSV?

Vesicle bases reveal intranuclear inclusions of keratinocytes and multinucleated giant cells (positive Tzanck smear).


What findings are present on skin biopsy of VSV?

Acantholysis (loss of intracellular connections) of keratinocytes and intraepidermical vessicles.


What are koliocytes?

Cytoplasmic vacuoles in keratinocytes.


In RA, bony swelling in what joints of the hands is present?

PIP joints (Bouchard's nodes); also metacarpophalangeal joints.


In Osteoarthritis, bony swelling in what joints of the hands may be present?

Can be in both PIP (Bouchard's) and DIP (Heberden's)


What type of tissue is present in keloid and hypertrophic scars?

Connective tissue rich in fibroblasts, myofibroblasts, and bundles of collagen fibers that lie in parallel arrangement in hypertrophic scars and in a disorganized fashion in keloids.


What is the mechanism of action and classification of Etanercept?

TNF-a inhibitor added to methotrexate to treat moderate to severe RA. It is a fusion protein linking a soluble TNF-a receptor to the Fc component of human immunoglobulin G1. It reduces the biological activity of TNF-a by acting as a decoy receptor.


The suffixes -mab, -cept, and -nib refer to what drug classes respectively?

-mab= monoclonal antibody; -cept= receptor molecule; nib= kinase inhibitor.


Reactive arthritis is associated with what serotype?



What is reactive arthritis?

A spondyloarthropathy that tends to affect HLA-B27 positive individuals following infections with Campylobacter, Shigella, Salmonella, Yersinia, Chlamydia, or Bartonella. It presents as asymmetric arthritis of the large joints and joint aspirates are always sterile (it is reactive, not infectious).