Uworld2

Question 1

How does carotid sinus hypersensititivity result in syncope?

Answer 1

Carotid sinus hypersensitivity is a common cause of syncope associated with tactile stimulation of the carotid sinus (eg, shaving).

The syncope results from an exaggerated vagal response stimulated by the carotid baroreceptors, which leads to slowed heart rate and marked peripheral vasodilation with a resulting transient loss of cerebral perfusion.

Question 2

What is congenital toxoplasmosis treated with?

Answer 2

Sulfadiazine plus pyrimethamine.

These medications work synergistically to inhibit formation of tetrahydrofolate, a necessary cofactor for purine nucleotide synthesis

Question 3

Prerenal acute kidney injury results from what? What are the lab findings?

Answer 3

Results from renal hypoperfusion (eg, dehydration due to poor oral intake).

Labs: elevated blood urea nitrogen/creatinine ratio (>20:1), low urine sodium (<20 mEq/L), low fractional excretion of sodium (<1%), high urine osmolality and specific gravity, and unremarkable urinalysis.

Question 4

Vitamin D def in children causes what?

Answer 4

This causes rickets characterized by excessive unmineralized osteoid matrix at the epiphyseal cartilage.

Question 5

What happens with vitamin D deficiency?

Answer 5

Vitamin D deficiency decreases intestinal absorption of calcium.

Parathyroid hormone secretion increases to maintain plasma calcium, which causes renal phosphate wasting and impaired bone mineralization.

Question 6

What is the most effective agents for the treatment of hypertriglyceridemia?

Answer 6

Fibrates (eg, fenofibrate)

In patients with severe hypertriglyceridemia, pancreatic lipases can cause toxic levels of free fatty acids to be released within the pancreatic tissue, leading to acute pancreatitis.

Question 7

What is the MOA of bisacodyl?

Answer 7

Bisacodyl is a commonly used stimulant laxative that stimulates the enteric neurons within the colonic myenteric plexus, thereby increasing peristaltic activity and enhancing colonic motility.

Question 8

What is focal dystonia?

Answer 8

Focal dystonia is a neurologic movement disorder characterized by sustained, involuntary muscle contraction.

Question 9

What is seen on muscle biopsy with focal dystonia?

Answer 9

Because these contractions are neurologically mediated, muscle biopsy may not show significant histologic changes, although muscle fiber hypertrophy is often present due to repetitive contractions.

Question 10

What is the criteria for hospice?

Answer 10

Patients with advanced metastatic cancers or other terminal illnesses and a life expectancy of less than or equal to 6 months should be evaluated for hospice care.

Question 11

What is leukocyte adhesion deficiency is due to what?

Answer 11

It due to the absence of CD18 antigens, which are necessary for the formation of integrins.

Failure of leukocyte adhesion and migration results in recurrent skin and mucosal infections without purulence, delayed umbilical cord separation, and peripheral leukocytosis.

Question 12

What does Vitamin A def cause?

Answer 12

It causes night blindness and hyperkeratosis.

Deficiency of this lipid-soluble vitamin can develop in patients with fat malabsorption due to chronic biliary obstruction, exocrine pancreatic insufficiency, or small-bowel resection.

Question 13

What can cause a traumatic pneumothorax?

Answer 13

Traumatic pneumothorax can involve puncture of either the chest wall (eg, penetrating chest trauma) or the lung (eg, by fractured ribs), allowing air to enter the pleural space.

Question 14

What are the symptoms from traumatic pneumothorax?

Answer 14

Patients usually experience chest pain and diffuculty breathing. Crepitus, caused by air in the subcutaneous tissues of the chest wall, is often present on PE.

Question 15

Where is the esophagus located on a CT?

Answer 15

The esophagus is located between the trachea and the vertebral bodies in the superior thorax.

It is typically collapsed with no visible lumen on CT images of the chest.

Question 16

What is the leading cause of acute exacerbations of chronic obstructive pulmonary disease?

Answer 16

Viral and bacterial respiratory infections. The most common viral pathogens are: rhinovirus, influenza, and respirartory syncytial virus.

Question 17

An aneurysm of the internal carotid artery can laterally impinge on the optic chiasm. This can cause what?

Answer 17

This can cause ipsilateral nasal hemianopia by damaging uncrossed optic nerve fibers from the temporal portion of the retina.

Question 18

Hyper-IgM syndrome is usually caused by?

Answer 18

It is usually caused by a defect in CD40 ligand, which prevents B cells from undergoing class-switch recombination.

Question 19

What are the clinical features of hyper-IgM syndrome?

Answer 19

Clinical features include recurrent sinopulmonary, gastrointestinal (eg, Giardia), and opportunistic infections,

Lab findings include elevated IgM and low/absent IgG, IgA, and IgE.

Question 20

What is indicative of extramedullary hematopoiesis?

Answer 20

The presence of erythroid precursors in the liver and spleen.

Question 21

What is extramedullary hematpoiesis?

Answer 21

A condition characterized by erythropoietin-stimulated formation and maturation of blood cells outside of the bone marrow.

It occurs in response to severe chronic hemolytic anemia (eg, beta thalassemia).

Question 22

Patients with T1DM are increased risk of hypoglycemia because?

Answer 22

Because exogenous insulin will continue to be absorbed from the injection site despite falling glucose levels.

Those with long-standing diabetes may also have decreased glucagon secretion and therefore have an even greater risk of rapid hypoglycemia.

Question 23

Infective endocarditis in IV drug users commonly affects what heart valve?

Answer 23

Commonly affects the tricuspid valve, often leading to septic pulmonary emboli.

Patietns can have an early- or holo-systolic murmur or tricupsid regurgitation, which is best ausculated in the 4th or 5th intercostal space at the left lower sternal border.

Question 24

What is the MOA of nitroglycerin?

Answer 24

A venodilator that increases venous capacitance to reduce venous return and shift the vascular function curve to the left.

Question 25

Alcoholic hepatitis presents how on histo?

Answer 25

Histopathology is characterized by marked intrahepatic neutrophil infilration, hepatocellular ballooning, Mallory bodies, and steatosis.

Question 26

Typical labs of alcoholic hepatitis?

Answer 26

Elevated aminotransferases with an AST/ALT ratio >2:1

Question 27

What is the presentation of congenital toxoplasmosis?

Answer 27

It is an infection acquired in utero that can present with hydrocephalus, intracranial calcifications, and chorioretinitis due to prolonged CNS inflammation.

Question 28

What is the main pacemaker of the heart?

Answer 28

The sinoatrial node is the main pacemaker of the cardiac conduction system, typically initiating electrical impulses at a rate of 60-100/min.

Question 29

What are the other pacemakers in the heart?

Answer 29

Other parts of the conduction system (eg, atriventricular node, His bundle) have their own intrinsic pacemakers, and they initiate impulses at a slower rate when impulses from the sinoatrial node are blocked.

Question 30

What is MOA abciximab?

Answer 30

Abciximab is a blocker of glycoprotein (GP) IIb/IIIa receptor, which normally promotes platelet binding to fibrinogen.

Question 31

What is defective in Glanzmann thrombasthemia?

Answer 31

GP IIb/IIIa.

Question 32

What is hand-foot-and-mouth disease?

Answer 32

Hand-foot-and-mouth disease is a common childhood illness characterized by painful, vesicular mouth lesions; ulcers on the extremities; and low-grade fever. It is caused by the ingestion and subsequent dissemination of an enterovirus (eg, Coxsackievirus)

Question 33

Antidepressants monotherapy should be avoided in what patients?

Answer 33

Patients with bipolar disorder due to the risk precipitating mania.

Question 34

Supine patients aspirate into which lung lobes?

Answer 34

Due to gravity, supine patients typically aspirate into the posterior segments of the upper lobes and superior segments of the lower lobes.

Question 35

Patients who are upright will aspirate into what lung lobes?

Answer 35

Patients who are upright tend to aspirate into the basilar segments of the lower lobes.

Question 36

Aspirated material will travel down which bronchus?

Answer 36

Aspirated material is more likely to travel down the right main bronchus.

Question 37

Biliary atresia (obstruction of extrahepatic bile ducts) presents with what and on biopsy?

Answer 37

Presents with jaundice, dark urine, and acholic stools in the first 2 months of life due to conjugated hyperbilirubinemia. Biopsy reveals intrahepatic bile duct proliferation, portal tract edema, and fibrosis.

Question 38

Traits of enterococcus

Answer 38

Gram+, cocci in pairs and chains and when grown on blood agar, they do not cause hemolysis (gamma-hemolytic) It is an important cause urinary tract infections.

Question 39

Patients with cirrhosis complicated by abdominal ascites may develop what?

Answer 39

Hepatic hydrothorax, which is a transudative, usually right-sided pleural effusion that results from passage of intraabdominal fluid into chest cavity through small fenestrations in the diaphragm.

Question 40

First generations antihistamines will have what kind of effects?

Answer 40

First generation antihistamines are nonspecific and interact with multiple receptors, including the muscarinic receptor. This leads to anticholinergic effects (eg, fever, flushing, mydriasis, urinary retention, tachycardia, altered mental status)

Question 41

Antibiotics disrupt the normal intestinal flora and can allow for overgrowth of what?

Answer 41

Clostridioides difficile, an anaerobic, gram+, spore forming bacillus. C. difficile produces 2 toxins that penetrate colonic epithelial cells leading to watery diarrhea, abdominal cramping, and colitis.

Question 42

What is highly suggestive of a C difficile infection?

Answer 42

The presence of a pseudomembrane (exudate on colonic mucosa consisting of fibrin and inflammatory cells).

Question 43

Listeria monocytogenes traits

Answer 43

Gram+ rod associated with outbreaks of gastroenteritis via ingestion of contaminated foods (eg, unpasteurized milk, deli meats). It can cause sepsis in susceptible patients, including neonates, older adults, pregnant women, and immunocompromised individuals.

Question 44

A drug that binds to and activates GABA-A receptors (or enhances their activity) will do what?

Answer 44

It will increase the conductance of chloride ions, leading to increased passive transport of chloride into the cell interior. This causes the membrane potential to become hyperpolarized (more negative than the resting membrane potential) by approaching or reaching the equilibrium potential for chloride.

Question 45

Presentation of tension headache

Answer 45

They are characterized by an achy or pressure-like pain that is often bilateral and associated with pericranial muscle tenderness.

Question 46

How is leuprolide used to treat prostate cancer?

Answer 46

It is a GnRH agonist. It initially stimulates pituitary LH secretion, which leads to a rise in androgen levels. However, the GnRH receptor is subsequently down-regulated, which dramatically drops LH release and leads to a long-term decrease in androgen production.

Question 47

What is naloxone?

Answer 47

Naloxone is a short-acting opiod antagonist used for the treatment of opioid overdose (eg, respiratory depression, decreased level of consciousness, miosis, decreased bowel sounds.) Naloxone frequently requires redosing to prevent recurrent overdose symptoms due to its short half life (<1 hr).

Question 48

What is the most common place for an anal fissure?

Answer 48

Anal fissures are longitudinal tears in the mucosa. They are usually due to passage of hard stool in patients with chronic constipation. Most fissures occur at the posterior midline, likely due to decreased blood flow in this area.

Question 49

How does primary varicella zoster virus infection present?

Answer 49

Primary varicella zoster virus infection presents with a prodromal illness (eg, fever, malaise) followed by pruritic, vesicular lesions that appear in successive crops in different stages.

Question 50

When is ADHD diagnosed?

Answer 50

Not until age >4

Question 51

What is the first line treatment for localized psoriasis?

Answer 51

First-line treatment options for localized psoriasis include high-potency topical corticosteroids and vitamin D analogs. Vitamin D analogs inhibit T-cell and keratinocyte proliferation and stimulate keratinocyte differentiation. Corticosteriods also have anti-inflammatory and antiproliferative properties; their MOA is complementary to the vitamin D analogs.

Question 52

What are the derivatives of the endoderm?

Answer 52

GI tract, liver, and pancreas.

Question 53

What are nicotinic receptors?

Answer 53

Nicotinic receptors are ligand-gated ion channels that open after binding acetylcholine. This results in an immediate influx of Na+ and Ca2+ into the cell and an outflux of K+ from the cell.

Question 54

Membranoproliferative glomerulonephritis typically caused by?

Answer 54

Immune complex deposition within the glomerular capillary walls and mesangium and can be associated with chronic infections (eg. hep B) Characterized by large, hypercellular glomeruli with thickened capillary walls.

Question 55

What is on EM and IF for membranoproliferative glomerulonephritis?

Answer 55

IF: granular pattern of IgG and C3 EM: subendothelial and mesangial deposits

Question 56

What is a branchial cleft cyst? location and result

Answer 56

Branchial cleft cyst are most often located anterior to the sternocleidomastoid muscle and result from incomplete obliteration of a pharyngeal cleft (or groove). Patients typically have a tender, fluctuant mass (due to secondary infection) with or without purulent drainage.

Question 57

What are the features of chronic bronchitis?

Answer 57

Thickened bronchial walls, lymphocytic infiltration, mucous gland enlargement, and patchy squamous metaplasia of the bronchial mucosa. Tobacco smoking is the leading cause.

Question 58

What is severe combined immunodeficiency?

Answer 58

Caused by a genetic defect in T cell development, leading to loss of both cellular and humoral immunity. Patients present in infancy with recurrent bacterial, viral, fungal, and opportunisitic infections as well as failure to thrive and chronic diarrhea.

Question 59

What does the candida antigen skin test assess?

Answer 59

The Candida antigen skin test assesses the activity of cell-mediated immunity because it requires an intact CD4 cell response. Failure to respond to candida antigen testing is typical in patients with severe combined immunodeficiency.

Question 60

DNA-binding proteins include what?

Answer 60

-transcription factors (Myc, CREB) -steroid receptors (cortisol, aldosterone, progesterone) -Thyroid hormone receptor -fat soluble vitamin receptors (vit D, retinoid acid) -DNA transcription and replication proteins

Question 61

What are gap junctions?

Answer 61

Gap junctions facilitate communication and coordination between cells and play an important role in labor contractions. Gap junctions are composed of connexin proteins, which are upregulated in the uterus in response to rising estrogen levels.

Question 62

Ulnar nerve injury most commonly occurs where and presents how?

Answer 62

Ulnar nerve injury most commonly occurs at the elbow (eg, compression due to resting arm on a hard surface for prolonged periods) and usually presents with discomfort and sensory loss and/or paresthesia in the 5th digit, medial half of the 4th, and the hypothenar eminence. In severe injury, patients can also have impaired wrist flexion and adduction along with finger weakness or clumsiness.

Question 63

Atopic dermatitis is caused by what?

Answer 63

Atopic dermatitis presents with dry, erythematous patches or papules that are caused in part of a Th2-skewed immune response. Th2 cytokines (eg IL-4, IL-13) stimulate IgE prodution, suppress epidermal barrier component expression, and impair host immune responses against secondary microbial infections.

Question 64

What is the Km and Vmax for competitive inhibitors?

Answer 64

Competitive inhibitors compete with substrate for active binding sites on enzymes. Additional substrate is required to achieve the same rate of reaction, increasing the measured value of the Michaelis constant (Km). Competitive inhibitors do not affect enzyme function; therefore, maximal velocity (Vmax) is unchanged in their presence.

Question 65

Herpes zoster ophthalmicus is caused by viral reactivation within what nucleus?

Answer 65

The trigeminal nucleus. It affects the ophthalmic branch of the trigeminal nerve (CNV1) and can lead to blindness due to acute keratitis because V1 conveys sensory information from the cornea.

Question 66

MOA of fenoldopam

Answer 66

Selective peripheral dopamine-1 receptor agonist. It causes vasodilation of systemic and renal arterioles to lower blood pressure while also increasing renal perfusion, urine output, and natriuresis, making it useful in the treatment of hypertensive emergency patients with renal insufficiency.

Question 67

What is myopia (nearsightedness)?

Answer 67

A refractive error in which the focal point of an image falls anterior to the retina due to an increased anterior-posterior diameter of the eyes. Patients have difficulty seeing objects at a distance and have normal near vision.

Question 68

Arginase deficiency results in what?

Answer 68

Arginase is a urea cycle enzyme that produces urea and ornithine from arginine. Arginase deficiency results in progressive spastic diplegia, growth delay, and abnormal movements. Treatment: arginine-free, low protein diet

Question 69

What is neonatal abstinence syndrome?

Answer 69

Caused by infant withdrawal to opiates (eg, heroin) and usually presents in the first few days of life. Characterized by irritability, a high pitched cry, poor sleeping, tremors, seizures, sweating, sneezing, tachypnea, poor feeding, vomitting, and diarrhea.

Question 70

What are beta-lactamase inhibitors? Concurrent administration does what?

Answer 70

Clavulanic acid, sulbactam and tazobactam. Concurrent administration of clavulanate with amoxicillin expands amoxicillin's spectrum of activity to include strains of B-lactamase synthesizing bacteria that are resistant to amoxicillin alone.

Question 71

In the HIV replication cycle, polyprotein precursors are encoded by the structural genes gag, pol, and env. Which one is glycosylated?

Answer 71

Only the env gene polyprotein product (gp160) is glycosylated. This polyprotein is subsequently cleaved in the Golgi apparatus to form the envelope glycoproteins gp120 and gp41

Question 72

Paramesonephric (Mullerian) ducts form what in females?

Answer 72

In females, the paramesonephric (Mullerian) ducts fuse to form the fallopian tubes, uterus, cervix, and upper vagina. Disruptions in this process can lead to various Mullerian duct anomaloes (eg bicornuate uterus, uterine didelphys). Renal anomalies are a common comorbidity.

Question 73

What are the types of strep pneumo vaccines?

Answer 73

Strep pneumo vaccination reduces the risk of invasive disease and is recommended for young patients and the elderly. The pneumococcal polysaccharide vaccine is an unconjugated vaccine that induces a T-cell independent humoral immune response The pneumococcal conjugate vaccine contains polysaccharide material attached to a protein antigen, which creates a robust T cell mediated humoral immune response.

Question 74

Congenital goiter in the setting of hypothyroidism (ie, increase TSH, low thyroxine) is caused by?

Answer 74

Caused by transplacental passage of maternal antithryoid medications (eg, propylthiouracil), which inhibit thyroid peroxidase and are used to treat maternal hyperthroidism.

Question 75

Renal artery stenosis causing significant renal hypoperfusion will result in what?

Answer 75

A decreased glomerular filtration rate and activation of the renin-angiotensin-aldosterone system. This leads to increased renin release by modified smooth muscle (juxtaglomerular) cells in the walls of afferent glomerular arterioles. Chronic renal hypoperfusion can cause hyperplasia of the juxtaglomerular appartus.

Question 76

Biopsy of polymyositis shows what?

Answer 76

Patchy endomysial inflammatory infiltrate (ie, direct invasion of individual muscle fibers) -symmetrical proximal muscle weakness and associated with antinuclear and anti-tRNA synthetase (anti-Jo-1) autoantibodies

Question 77

Biopsy of dermatomyositis shows what?

Answer 77

Perifascicular inflammation (ie, localized around blood vessels and the septa between muscle fascicles) -symmetrical proximal muscle weakness and associated with antinuclear and anti-tRNA synthetase (anti-Jo-1) autoantibodies

Question 78

What is used to treat prolactinomas?

Answer 78

Dopamine agonists (eg, cabergoline) are used in patients with prolactin-secreting pituitary adenomas (prolactinomas) to suppress prolactin production and reduce tumor size. Prolactin is under negative regulation by dopaminergic neurons via the pituitary stalk.

Question 79

Gross pathology of Crohn disease

Answer 79

Skip lesions, cobblestoning of mucosa, bowel wall thickening and creeping fat.

Question 80

Type IV hypersensitivity reactions are mediated by what?

Answer 80

T lymphocytes mediate the inflammation in these reactions through cytokine release, CD8+ cytotoxicity, and macrophage recruitment.

Question 81

How does testicular germ cell tumors cause gynecomastia?

Answer 81

Secretion of hCG by testicular germ cell tumors impairs testosterone production in Leydig cells while increasing aromatase activity and conversion of androgens to estrogens. The resulting increase in the estrogen/androgen ratio can cause gynecomastia.

Question 82

What is Jervell and Lange-Nielsen syndrome?

Answer 82

AR disorder; profound bilateral sensorineural hearing loss and congenital long QT syndrome, which predisposes to ventricular arrhythmias and sudden cardiac death. This condition occurs secondary to mutations in genes that encode voltage-gated potassium channels

Question 83

What are the pulmonary volumes for COPD?

Answer 83

COPD causes air trapping and hyperinflation; these patients breathe at higher baseline lung volumes (higher functional residual capacity). The absolute volume of air in the lungs that is not respired (residual volume) increases substantially, as does the fraction of air in the lungs that is not involved in respiration (residual volume/total lung capacity ratio)

Question 84

Where does Herpes lie latent?

Answer 84

Primary genital herpes (herpes simplex virus type 1 or 2 infx) presents as multiple, grouped vesicles on the genitals that progress to ulcers. Primary infections can cause systemic symptoms (eg, fever, malaise) and painful inguinal lymphadenopathy. Because HSV can invade and lie latent in the sacral dorsal root ganglia, patients are at risk for viral reactivation and recurrent genital lesions.

Question 85

What is progressive multifocal leukoencephalopathy?

Answer 85

Patients with advances AIDS can have reactivation of JC virus, which causes progressive multifocal leukoencephalopathy. This condition usually presents with progressive confusion, ataxia, and motor deficits. Brain MRI reveals multifocal areas of white matter demyelination with no mass effect or enhancement.

Question 86

What are some comorbitites of prolactinomas?

Answer 86

In patients with prolactinoma, high levels of circulating prolatin suppress GnRH secretion from the hypothalamus, leading to reduced secretion of LH and subsequent hypogonadism, anovulation, and amenorrhea. The resulting estrogen def can cause osteoporosis with an increased risk for fragility fractures, and lead to vaginal dryness and atrophy.

Question 87

MOA of colchicine and AE

Answer 87

Colchicine inhibits tubulin polymerization into microtubules and can be used for acute treatment and prophylaxis of gout. Important side effects: nausea, abdominal pain, and diarrhea.

Question 88

What is adrenal crisis? And the treatment

Answer 88

Patients with adrenal insufficiency are not able to increase glucocorticoid productin in response to acute stress (eg, illness, surgery). Adrenal crisis: severe hypotension, abdominal pain, vomitting, weakness, and fever. In addition to aggressive fluid resuscitation, treatment requires immediate glucocorticord supplementation.

Question 89

What is adenomyosis?

Answer 89

Adenomyosis typically presents with regular (ie, cyclic), heavy, painful menses. Gross path: uniformly enlarged, globular uterus with the abnormal presence of endometrial glands and stroma in the myometrium.

Question 90

What is the MOA of budesonide?

Answer 90

Budesonida, like other glucocorticords, reduces inflammation by binding to a cytosolic receptor, translocating into the nucleus, and inhibiting proinflammatory transcription factors such as nuclear factor kappa-B (NF-kB). It is especially useful in reducting transmural bowel inflammation in patients with Crohn disease because it has high topical potency and limited systemic adverse effects due to its high first pass metabolism.

Question 91

What is atrial fibrillation? ECG?

Answer 91

Most common cause of an irregulary irregular rhythm. It often presents with palpitations and is confirmed by ECG showing an absence of organized P waves and irregulary irregular R-R intervals.

Question 92

What are the changes of pulmonary vascular resistance and systemic vascular resistance after birth?

Answer 92

After birth, pulmonary vascular resistance progressively decreases as systemic vascular resistance progressively increases. As the relative pressures in the pulmonary artery and aorta change, the murmur associated with ductus arterioles evolves from systolic only to continous before the duct closes, at which time the murmur disappears.

Question 93

Traits of Actinomyces and treatment

Answer 93

Actinomyces: anaerobic, G+ bacillus with acute angle branching. It can colonize intrauterine devices (IUDs) and may cause pelvic inflammatory disease (eg, fever, abdominal pain, mucopurulent cervical discharge) Treatment: IUD removal and Penicillin

Question 94

What is Neurofibromatosis type 1 due to?

Answer 94

Neurofibromatosis type 1 is a single-gene AD disorder that occurs due to mutation of the NF1 gene located on chromosome 17.

Question 95

What are the most common manifestations of neurofibromatosis type 1?

Answer 95

Cutaneous neurofibromas, cafe au lait spots, skinfold freckling, and Lisch nodules

Question 96

What is the most common pineal gland tumor?

Answer 96

Germinomas

Question 97

How do germinomas present?

Answer 97

Germinomas present with obstructive hydrocephalus and dorsal midbrain (Parinaud) syndrome. If in the suprasellar region: causes endocrinopathies due to pituitary/hypothalamic dysfunction.

Question 98

Dactylitis (painful swelling of the hands and feet) is a common presentation of what disease?

Answer 98

Sickle cell disease in young children. Sickling episodes result in hemolysis, which leads to increased indirect bilirubin and lactate dehydrogenase and decreased levels of haptoglobin.

Question 99

What antibodies are found in rheumatoid arthritis?

Answer 99

Rheumatoid arthritis results from an immune response directed against autoantigens in the joints. Infiltrating CD4+T cells secrete cytokines that promote inflammatory synovitis. They also stimulate B cells to produce rheumatoid factor (IgM antibody specific for Fc component of IgG) and anti-citrullinated protein antibodies that contribute to chronic inflammation and joint destruction.

Question 100

Graves ophthalmopathy is caused by?

Answer 100

Graves ophthalmopathy is caused by stimulation of orbital fibroblasts by thyrotropin receptor antibodies and cytokines released by activated T cells. Excess deposition of extracellular glycosaminoglycans and inflammatory infiltration lead to expansion of extraocular muscles and retro-orbital tissues.