Kaplan Flashcards

Question

What does Ixodes tick transmit

Answer 1

implicated in transmission of Babesia microti as well as Borrelia burgdorferi and Anaplasma (formerly Ehrlichia) phagocytophila.

Answer 2

Intraerythrocytic protozoan parasites and causes the clinical disease babesiosis. The most common appearance in blood smears is ring forms inside RBC, typically in combination with one or two chromatic dots. Geography includes East coast (e.g. MA) and Midwest (co-exists with Lyme disease and ehrlichiosis). Most patients are asymptomatic; symptomatic cases in reasonably healthy individuals develop fever, HA, chills and fatigue. Causes hemolytic anemia that is severe in splenectomized or severely debilitated patients; rarely can be fatal.

Answer 3

(1) bilirubin production in increased because of hemolysis of fetal RBCs as they are replaced with newly formed hemoglobin A-containing RBCs; the porphyrin of heme liberated by hemolysis is converted to bilirubin (2) hepatic excretory capacity of bilirubin is low at birth, in part because of low UDP-glucuronyl transferase in the perinatal period.

Answer 4

Neonatal hyperbilirubienmia occurs more frequently in boys and those of East Asian descent Treatment is with phototherapy because light decomposes bilirubin into water-soluble substances that are excreted in the urine. Another molecule that absorbs light is riboflavin (vitamin B2), which also degrades with phototherapy and thus must be supplemented to prevent deficiency.

Answer 5

If serum bilirubin levels increase too much, the unconjugated bilirubin can cause kernicterus (deposition of unconjugated bilirubin in basal ganglia), which can produce lifelong neurologic complications in surviving infants.

Answer 6

Increased total WBC count with a granulocytosis (including both the mature neutrophils and the immature band form neutrophils) with a left shift (meaning disproportionately large numbers of the immature neutrophil forms compared to the mature neutrophil forms). Persistence of neutrophils at high levels is almost always indicative of an infection with an extracellular bacterium because the primary mechanism of immune defense against extracellular bacteria is the production of antibodies and complement activation to cause opsonization, or enhancement of phagocytosis and killing by phagocytic cells such as neutrophils. Anemia is likely to be observed since most bacteria have extremely high nutritional requirements of iron, which they must scavenge from the host.

Answer 7

seen in immunocompromised; mononuclear response

Answer 8

monocytosis; principal immune response to intracellular organisms is TH1 cell, which secretes cytokines to stimulate the effector cells of cell-mediated immunity

Answer 9

eosinophilia; eosinophils act in concert with antiparasitic antibodies to promote antibody-dependent cell-mediated cytotoxicity (ADCC) against parasites.

Answer 10

intracellular parasites that would elicit a TH1 response and a monocytosis (granulocytes are increased in response to extracellular organisms)

Answer 11

Features include palpable tender LAD, preserved lymph node architecture, multiple large germinal centers, recognizable light and dark zones, frequent mitoses, tingible body macrophages (macrophage containing debris from ingested lymphocytes)

Answer 12

Occur when there is bony weakening due to another disease processes. Lytic bone lesions - multiple myeloma, lung carcinoma, or breast carcinoma Blastic bone lesions - prostate carcinoma or breast carcinoma

Answer 13

Causes thromobolysis through formation of an activator complex with plasminogen to cleave the arginine-valine bond of plasminogen, resulting in the formation of plasmin. Plasmin degrades fibrin and fibrinogen as well as the procoagulant factors V and VIII. The activator complex also diffuses into the thrombus, thereby activating preplasmin-2, which lyses fibrin, thus breaking up thrombi and potentially restoring blood flow to ischemic cardiac muscle.

Answer 14

analgesic and antipyretic indicated for the treatment of mild pain associated with muscle pain associated with arthritis, HA, and menstrual cramps as well as the treatment of fever; ineffective at reducing inflammation. Not associated with gastric distress and does not have the CV risk warning associated with NSAIDs and COX-2 inhibitors (also note that the COX-2 inhibitor celecoxib is contraindicated in patients with sulfonamide allergies)

Answer 15

metabolized by hepatic CYP450. Ketoconazole is an azole antifungal drug and a potent inhibitor of P450 enzymes, which will cause an increased warfarin effect and thus increased INR. Other antimicrobials that are P50 inhibitors are erythromycin, clarithromycin, ciprofloxacin, and the protease inhibitors used in treating HIV. Additional potent hepatic enzyme inhibitors include amiodarone, diltiazem, isoniazid, and fluoxetine. Conversely, potent hepatic enzyme inducers are carbamazepine, phenytoin, phenobarbital, rifampin, and St. John's wart.

Answer 16

Patients with leukemia are prone to develop uric acid kidney stones due to increased uric acid production due to increased purine breakdown, particularly during chemotherapy. Prevention of hyperuricemia and/or uric acid stone development in ALL patients is typically instituted with a xanthine oxidase inhibitor, such as febuxostat or allopurinol

Answer 17

urokinase-like PA (uPA), such as urokinase and streptokinase, and tissue PA (tPA), such as alteplase, reteplase, and tenecteplase

Answer 18

Native tPA is produced by endothelial cells and recombinant forms have been used extensively in the early treatment of MI to promote lysis of newly formed thrombi. Specifically, these agents bind to fibrin in a thrombus and convert the entrapped plasminogen to plasmin, resulting in fibrinolysis. Since thrombolytics like tPA, when given in pharmacologic doses, lead to the direct degradation of some fibrinogen as well as fibrin, the available fibrinogen for the common part of the pathway will be decreased, and both the intrinsic and extrinsic pathways will be partially blocked, leading to prolongation of both PT and PTT.

Answer 19

blood flow above and below the coarctation is normal despite a large difference in BP because the resistance above the coarctation has increased sufficiently to maintain the flow of blood at a normal level required to satisfy the metabolic requirements of the tissues. The pressure and resistance below the coarctation are normal

Answer 20

* >95% of coarctation occurs just distal to the left subclavian artery in the region of the ductus arteriosus. The descending thoracic aorta is supplied via reverse collateral flow in the intercostal arteries. These arteries, the major branch of which runs in the costal groove on the underside of the rib, expand and cause erosion of the inferior aspect of the rib (rib notching). * Disparity in pressure between upper and lower extremities

Answer 21

Failure of truncoconal septum to spiral. This is fatal if a shunt (e.g., PDA, VSD, ASD, PFO) is not present to mix the venous and systemic blood. Indomethacin closes PDA and Prostaglandin E1 (e.g. alprostadil or misoprostol) keeps PDA open

Answer 22

caused by failure of neural crest cells to migrate and are commonly seen in Down Syndrome (can present with characteristic physical findings including flat facial profile, prominent epicanthal folds, and a simian crease and duodenal atresia with the characteristic “double bubble” sign on x-ray.

Answer 23

potential space between the two layers of pericardium, the epicardium (also known as the visceral pericardium) and the parietal pericardium. Accumulation of blood in the pericardial space causes increased pressure on the heart, which restricts filling of the heart during diastole (cardiac tamponade). This reduced filling results in reduced CO and reduced BP.

Answer 24

the most common underlying cause is ischemic heart disease (IHD), which is most frequently related to atherosclerosis of the coronary arteries. Occlusion of a coronary artery can cause electrical instability, and can thereby cause an arrhythmia, leading to sudden cardiac death.

Answer 25

AD disease caused by defective or absent LDL receptors on liver cells. As a result, patients develop high levels of LDL cholesterol, leading to the early formation of atherosclerotic plaques, coronary artery disease, and MI and the appearance of xanthomas on the skin.

Answer 26

These patients often die in their twenties or thirties because of myocardial or cerebral infarction

Answer 27

Normally, the LDL-R is a cell surface receptor that recognizes apoprotein B 100 that is present in the cholesterol-rich LDL. The LDL-R is present in clathrin-coated pits, and when activated, leads to invagination and formation of clarithrin-coated vesicles intracellularly. This process is called receptor-mediated endocytosis. Once internalized, the vesicle will shed its clathrin coat and fuse with an endosome, where the low pH cause release of the LDL particles from the receptors. The LDL particles are delivered to a lysosome, where they are degraded, releasing free cholesterol within hepatocytes.

Answer 28

Most disease processes that affect BUN and creatinine cause both to rise together. An exception to this rule is early CHF (low BP, cardiac enlargement, and perihilar infiltrates seen on CXR), in which the BUN can rise selectively.

Answer 29

provided by R/L coronary arteries, which are branches of the ascending aorta

Answer 30

* Right Coronary Artery - supplies the RA, RB, the SA and AV nodes, and parts of the LA and LV. The distal branch of the right coronary arterial (in 70% of subjects) is the posterior interventricular artery that supplies, in part, the posterior aspect of the interventricular septum. * Left Coronary Artery - supplies most of the LV, LA, and the anterior part of the interventricular septum., The two main branches are the anterior interventricular artery (LAD, and circumflex artery.

Answer 31

In MI, the LAD is obstructed in 50% of cases, the right coronary in 30%, and the circumflex in 20% of cases.

Answer 32

When the left ventricular wall moves paradoxically (i.e. bulges outward during systole and inward during diastole), think of MI secondary to occlusion of the LAD.

Answer 33

irregularly irregular ventricular rhythm without discrete P waves. The QRS complex is often narrow, but may be widened if aberrant conduction or bundle branch block is present. Medications that slow ventricular rate include digoxin, CCBs, and BBs.

Answer 34

Beta-blockers such as esmolol and metoprolol, and CCBs such as verapamil and diltiazem, are generally considered to be the treatment of choice for atrial fibrillation in patients without evidence of heart failure. Digoxin can also be used; it decreases conduction through the AV node and can be used for AFib with rapid ventricular rate.

Answer 35

Beta 1 selective blockers include "A-BEAM" = acebutalol, betaxolol, esmolol, atenolol, metoprolol; can also remember that A-M are cardioselective (beta 1) vs. N-Z are non-selective (beta 1 and 2) and the exceptions include carvedilol and labetalol (block both alpha 1 and beta receptors) - Remember that B1 receptors predominate in the heart, while B2 receptors predominate in the lungs - Beta-adrenergic blockers prevent angina by decreasing myocardial oxygen requirements during exertion and distress through the reduction of HR, myocardial contractility and BP. Beta-blockers are considered first-line agents in the treatment of chronic angina. - The beta-1 selective agents are most commonly used in the treatment of stable angina. However, beta-blockers with intrinsic sympathomimetic activity (e.g. acebutolol and pindolol) are not recommended for patients with angina because they may exacerbate the angina in some patients. - In addition to BBs, exertional angina can be treated with CCBs (amlodipine, felodipine, nifedipine) and/or isosorbide mononitrate or transdermal nitroglycerine.

Answer 36

Common cause of thrombus formation (mainly when it has not been appropriately treated). Premortem thrombi are characterized by thin, white laminations (lines of Zahn) composed mostly of platelets, whereas postmortem clots do not show lines of Zahn but instead resemble chicken fat.

Answer 37

no correlation of P waves and QRS complexes. The combination of increased pulse pressure (systolic - diastolic; normally is 40mmHg) and a decreased HR (30-45/min) should suggest this diagnosis.

Answer 38

Most commonly caused by coronary artery disease or degeneration of the cardiac conduction system with agents known to cause AV block (i.e. atenolol at high doses may cause different degrees of heart block). The initial management can be with atropine, isoproterenol, and dopamine.

Answer 39

sharp, stabbing pain that worsens with inspiration and is improved when sitting up and leaning forward. Diffuse ST elevations are a characteristic finding early in acute pericarditis. Generally is preceded by a viral upper respiratory illness, although patients often cannot recall any preceding illness.

Answer 40

Some patients can have palpitations or even syncopal episodes, while others may be completely asymptomatic Can present after MI in which tissue damage in ventricular tissue produces ectopic (non-SA node) sites of electrical activation. When these sites depolarize, the ventricles contract independently of the SA node and the atypical activation patterns generate the premature and abnormal QRS patterns seen on ECG. Typically, p waves do NOT precede a PVC since the electrical impulse originates in the ventricles, rather than the atria.

Answer 41

Do not allow sufficient time for normal ventricular filling to take place. As a result, preload (left ventricular end-diastolic volume) is reduced. Occurs independently of atrial contraction. Reduced filling time generates reduced SV during this contraction. The ventricular contraction closes the AV valves, so the atria eventually contract against closed AV valves, producing an abnormally high atrial pressure and "cannon a waves" on jugular vein pressure tracing.

Answer 42

indicates elevated jugular venous pressure, a classic sign of venous HTN, which can be caused by right-sided HF. JVD is a reflection of RA pressure adn can be used to estimate central venous pressure, which is normally less than 8.

Answer 43

In CHF there is activation of the RAAS, casuing salt and water retention. If the heart is not damaged too badly, the increase in blood volume caused by the fluid retention can increase venous return sufficiently to totally compsenate for the diminished pumping capacity of te heart. The increase in venous return causes the right atrial pressure to rise, which elevates venous pressure throughout the body. This increase in venous pressure can cause both excessive fluid loss from microcirculation and the development of peripheral edema. o This excess fluid, combined with decreased cardiac contractility, causes an increase in hydrostatic pressure. o Consequently, there is passage of fluid from the microcirculation to the interstitialspace, leading to edema. o The presence of S3, heard best over the apex, is evidence of CHF.

Answer 44

The body tries to maintain mean systemic filling pressure (MSFP) after a major hemorrhage by constricting veins and venules

Answer 45

accumulation fo fluid in the pleural cavity; may be a transudate or exudate

Answer 46

Exudative effusions with high lipid content, thus giving it a milky-white appearance, and originate from the lymphatic channels. They are most commonly related to disruption or obstruction by trauma or malignancy (lymphoma, knife stabbing near lymphatic channels) Exudative effusions have a pleural fluid to serum protein ratio of >0.5 and a pleural fluid to serum LDH ratio of >0.6, or pleural fluid LDH > 2/3 the upper limit of normal serum value. Lymphoma or a large tumor in the chest can damage the thoracic duct, allowing the chylomicron-rich lymphatic fluid to drain into the pleural cavity (chylothorax).

Answer 47

Bacterial pneumonia can lead to empyema and cause an exudative effusion and purulent pleural fluid with a yellow-green appearance (pus) on throacentesis. CHF (back-up of blood flow within lung capillaries and increased hydrostatic pressure) and neprhortic syndrome (loss of albumin and decreased oncotic pressure) contribute to transudative pleural effusions. Fluid will be clear yellow, ressembling serum.

Answer 48

severe cases are associated with increased LV pressure and increased LV work, increased LV oxygen consumption and decreased cardiac tissue oxygen concentration, and increased adenosine in cardiac tissue.

Answer 49

Blood flow through the coronary circulation is regulated almost entirely by the metabolic requirements of the cardiac muscle. When oxygen consumption of the heart increases, a larger-than-normal proportion of the ATP in the heart-muscle cells degrades to adenosine. The adenosine then dilates the coronary blood vessels, increased O2 delivery to an adequate level. In this way, the coronary blood flow increases in direct proportion to the oxygen consumption of the heart.

Answer 50

Staph aureus – gram+ coagulase + cocci in clusters; classically results from IV drug abuse, and since the pathogen is mostly introduced via venous access, bacterial vegetations most commonly form on the right side of the heart, especially the tricuspid valve.

Answer 51

Septic emboli thrown off from the tricuspid valve will mostly affect the pulmonary circulation rather than the systemic circulation. As a result, a pulmonary abscess can occur. Prerenal azotemia, splenic abscess and stroke are typically produced with left-sided involvement of endocarditis. They occur as a result of septic emboli released into the systemic circulation that can lodge in renal vasculature (renal infarcts), in the spleen (abscess), or in the cerebral vessels (stroke).

Answer 52

Oxygen Consumption Equation = CO (arterial O2 content - venous O2 content)

Answer 53

MAP = CO * TPR. However, if venous pressure (or right atrial pressure) is severely increased, it must be taken into account when estimating TPR such that the equation becomes MAP - RA pressure = CO * TPR

Answer 54

Cause of Chagas disease (endemic in vast areas of South America), spread by triatomids called reduviid bugs ("kissing bugs"). Intracellular protozoan that localizes mainly in the heart and nerve cells of the myenteric plexus, leading to myocarditis and dismotility of hollow organs, such as the esophagus (producing achalasia), colon and ureter.

Answer 55

ARDS results from alveolar injury, which causes the release of pro-inflammatory cytokines (TNF, IL-1, IL-6). Neutrophils are recruited to the lungs by these cytokines, where they become activated and release toxic mediators that damage alveolar epithelium and capillary endothelium (increasing microvascular permeability). This then allows protein to escape from the vascular space, producing an oncotic gradient, and fluid enters the interstitium, overwhelming the lymphatics. Alveolar spaces become filled with bloody, proteinaceous edema fluid and cellular debris from cells undergoing necrosis. Functional surfactant is lost causing alveolar collapse. These processes cause impaired gas exchange, decreased lung compliance, and pulmonary HTN.

Answer 56

Qf = k [(HPc + OPi) - (HPi + OPc)]. A positive Qf (net fluid movement between compartments) indicates net filtration and a negative value indicates net reabsorption. Sepsis can cause a generalized increase in vascular permeability, which can in turn lead to increased interstitial colloid osmotic pressure, increased interstitial fluid hydrostatic pressure, and increased lymph flow

Answer 57

* A decrease in systemic arterial pressure leads to a compensatory increase in BP and CO (secondary to an increase in sympathetic outflow and decrease in parasympathetic outflow). * Increased sympathetic activity at arterioles causes greater NE release, leading to enhanced alpha-1-adrenergic receptor stimulation, which are linked to Gq causing PIP2 hydrolysis forming IP3 and DAG. DAG travels to the membrane to activate PKC. IP3 is water-soluble and diffuses in the cytoplasm to internal storage vesicles to release calcium. Calcium then binds calmodulin to form a complex that activates MLCK which phosphorylates myosin light chains, leading to the interaction of myosin with actin to cause smooth muscle contraction, increasing BP. Vasopressin and ATII would also increase IP3. * An increase in systemic arterial pressure leads to a compensatory dilation of the arterioles and decreases CO (secondary to a decrease in sympathetic outflow and increase in parasympathetic outflow)

Answer 58

Arterial barorecerptors located in the carotid sinus (innervated by CN IX) and aortic arch (innervated by CN X) respond to stretching of the arterial wall. Information is sent to the nucleus tractus solitarius (NTS) in the medulla Trigger of the baroreceptor reflex, which increases sympathetic activity and decreases parasympathetic (vagal) activity causing an increase in HR and TPR (via stimulation of alpha-1 adrenergic receptors with NE from sympathetic outflow. Decreased blood flow to the kidney activates the RAAS.

Answer 59

Severe cell damage can release K+ into the bloodstream, producing hyperkalemia. On EKG, hyperkalemia is associated with abnormally tall, tented T waves because K+ is responsible for repolarization of cardiac cells

Answer 60

decreased SV, decreased CO, increased SVR, increased preload

Answer 61

decreased SV, unchanged CO, increased SVR; similar to cardiogenic shock, but with decreased cardiac preload instead of increased preload.

Answer 62

increased SV, increased CO, decreased PVR

Answer 63

increased SV, increased CO, unchanged SVR

Answer 64

During each cardiac cycle, the walls of the ventricle undergo both isometric (muscle length does not change) and isotonic (muscle length does change with a constant tension on the muscle) contraction and relaxation Phase 3 corresponds to a period of isometric contraction, referred to as the period of isovolumetric/isovolumic/isometric contraction. The ventricle is contracting and the pressure is rising rapidly, but the volume of the ventricle remains constant; thus, muscle length is relatively constant. During this phase, the rate of rise of the LV pressure reaches its maximum value, the +dP/dt max.

Answer 65

An AV fistula can shift the venous return curve to the right and rotate it upward with no change in the CO curve

Answer 66

Exercise can shift the venous return curve right and the CO curve upward

Answer 67

HF due to impaired contractility and narcotic overdose can shift the CO curve downward without directly affecting the venous return curve.

Answer 68

• Hemorrhage shifts the venous return curve left and shifts the cardiac output curve downward

Answer 69

antibiotic antineoplastic agent commonly used in the treatment of Hodgkin lymphoma, breast, endometerial, lung, and ovarian cancers. It intercalates DNA, forms free radicals, and inhibits topoisomerase

Answer 70

Both doxorubicin and daunomycin are associated with the development of congestive cardiomyopathy/CHF (classic S/Sx including orthopenia, paroxysmal nocturnal dyspnea, nocturia, tachycardia, pitting edema, pulmonary rales, S3 sound). Doxorubicin cardiotoxicity can be acute, occurring during and within 2-3 days of administration. Dexrazoxane is an iron-chelating agent that is used to prevent cardiotoxicity.

Answer 71

Afferent CN II, efferent CN III Light shined in eye → impulses carried in CN II to pretectal nuclei which innervate the Edinger-Westphal nulcei (preganglionic parasympathetic CN III neurons) bilaterally → innervate ciliary ganglia (postganglionic parasympathetic neurons) → sphincter pupillae muscle of iris → pupillary constriction Because shinning light in one eye causes bilateral stimulation of EW nuclei, it leads to constriction of the ipsilateral pupil (direct light reflex) and contralateral eye (consensual light reflex)

Answer 72

If you have lesion right CN II, right eye will not transmit light information to elicit either a direct or consensual response. However, when light is shined in healthy left eye, light information is transmitted fine and constriction occurs in both eyes

Answer 73

Relative afferent pupillary defect; decreased sensitivity of the affected eye to light, which results from lesions of the retina, optic nerve, or eye. Swinging flashlight test – shine light in Marcus Gunn pupil (pupils do not constrict fully), shine light in normal eye (pupils constrict fully), shine light in affected pupil again (apparent dilation of both pupils because the stimulus carried by the optic nerve [CN II] of the affected eye is weaker than the normal eye)

Answer 74

slow or sudden loss of central visual fields; peripheral fields are preserved, as is some useful color vision.

Answer 75

Dry (atrophic) macular degeneration (80%) – alterations in the retinal epithelium are seen, as are drusen deposits in the maculae Wet (exudative) macular degeneration – network of new vessel formation behind the retina that can be a source of intraretinal hemorrhage and subretinal fluid. This type can eventually contract with scar formation. Accounts for >80% of patients with AMD who have severe visual loss or legal blindness.

Answer 76

Innervates the levator palpebrae superiorsis, which elevates the eyelid. Also contains preganglionic parasympathetic fibers that synapse in the ciliary ganglion on postganglionic parasympathetic nerve fibers that innervate the sphincter papillae muscle, which constrict the pupil. Constricts pupil (sphincter pupillae) Accommodates (focus for near vision; ciliary muscle) Innervates extraocular muscles (MR, SR, IR, IO). Adduction (looking toward the nose, MR) is the most important function Raises eyelid (levator palpebrae)

Answer 77

* Dropping of eyelid (ptosis), dilation of pupil (mydriasis), and loss of pupillary constriction producing a loss of pupillary direct and consensual light reflex, and loss of pupillary constriction in response to accommodation in that eye * Inability to adduct the affected eye, leading to diplopia (double vision) on horizontal gaze, and the inability to focus for near vision

Answer 78

normal perception but perception is devoid of meaning; i..e loss of the ability to recognize objects, persons, sounds, shapes, or smells even when the specific sense and memory are intact.

Answer 79

inability to recognize familiar objects despite the ability to see them; produced by lesions in the temporo-ocipital association cortex (the “what” pathway)

Answer 80

special type of visual agnosia characterized by inability to recognize faces; seen with infarcts of the non-dominant (usually right) occipital cortex (PCA) or from bilateral lesions of the fusiform gyri.

Answer 81

Relapsing neurologic deficits with periods of remission Clinical Features – optic neuritis, internuclear opthalmoplegia (MLF), motor and sensory deficits, vertigo, Plaques (demyelination), increased IgG (oligoclonal bands) in CSF from lumbar puncture, and is associated with HLA-DR2. Treatmetn with high-dose steroids and IFNB

Answer 82

Lessens severe chronic pain by overly stimulating the involved neurons. This is thought to trigger inhibitory interneurons in lamina II of the spinal cord, thereby partially blocking the transmission of pain impulses; these interneurons are considered “gate-keepers” (gate theory of pain) that to some degree can isolate the peripherally generated signals from the brain.

Answer 83

seperates caudate and thalamus from lenticular nucleus. Recieves blood supply from the middle cerebral artery (lenticulostriate arteries), which are prone to rupture in unctolloed HTN (lacunar infarcts)

Answer 84

Anterior limb – conveys frontopontine fibers Genu – conducts corticobular fibers Posterior limb – conveys corticospinal fibers to contralateral arm and leg. Thus, hemorrhage of the left internal capsule can result in right-sided dense hemiplegia in which paralysis of the arm and leg are of the same intensity. Lower facial paralysis is the result of an UMN which is also consistent with a stroke of the left internal capsule (this is because the facial nucleus for the upper part of the face receives bilateral UMN innervation, wheras the facial nucleus fow lower part only receives contralateral UMN innervation).

Answer 85

lies in the tonsillar fossa

Answer 86

triangular area formed by cerebellum, upper medulla, and middle cerebellar peduncle. The facial nerve and the vestibulocochlear nerve emerge from the brain stem at the cerebellopontine angle and thus will be affected by a tumor in this region; most commonly an acoustic neuroma (80%) or meningioma (20%).

Answer 87

give rise to pseudounipolar cells of spinal and cranial nerve ganglia, Schwann cells, multipolar ganglion cells of autonomic ganglia, chromaffin cells of the adrenal medulla, odontoblasts, melanocytes, and cells that make the leptomeninges (pia and arachnoid).

Answer 88

gives rise to astrocytes, ependymal cells and oligodendrocytes

Answer 89

due to the teratogenic effects of mumps; can result in proximal ventricular enlargement and a noncommunicating hydrocephalus (i.e. enlarged lateral and third ventricles and a normal sized forth ventricle). The cerebral acqeduct connects 3rd to 4th ventricle and is in the midbrain (mesencephalon).

Answer 90

* Pharyngeal arch 3 gives rise to internal carotid artiers, which form the anterior circulation (middle and anterior cerebral arteries) of the circle of Willis * Pharyngeal arch 4 gives rise to the subclavian arteries, which form the posterior circulation (vertebral arteries) of the circle of Willis * NOTE – pharyngeal arch 1 gives rise to maxillary artery, 2 to stapedial artery, 5 degenerates early in fetal development, 6 gives rise to pulmonary arteries and to ductus arteriosus.

Answer 91

Olfactory nerves are the neurons on the mucosal side of the cribriform plate that send processes through the plate to synapse in the olfactory bulb, which in turn sends axons to the piriform cortex (primary olfactory cortex), that overlies the uncus of the temporal lobe. Smell is the only sensation that does not require thalamic relay for sensation.

Answer 92

* Damage to the olfactory nerve or bulbs (head injury, severe infection, meningiomas) causes anosomia (i.e. loss of sense of smell) * Uncus – seizures often originate here and have auras consisting of disagreeable odors. When the intracranial pressure increases, the uncus can press against the brainstem and CN (oculomotor nerve → blow pupil) during an uncal herniation.

Answer 93

innervates the perineum and originates from S2-S4 and leaves the pelvis through the greater sciatic foramen, then wraps around the ischial spine (seperates the greater sciatic foramen from lesser sciatic foramen) and sacrospinous ligament to enter lesser sciatic foramen and eventually reach the perineum.

Answer 94

Palpation of the ischial spine allows the physician to locate the pudendal nerve in order to perform a pudendal nerve block through the transvaginal approach

Answer 95

The three most common neonatal pathogens associated with meningitis include Group B Streptococcus (e.g., Streptococcus agalactiae), E. coli (K1), and Listeria monocytogenes.

Answer 96

MacConkey agar differentiates pathogens that can ferment lactose and colonies capable of this metabolism will grow as pink colonies. E. coli and Klebsiella both grow as pink colonies on MacConkey agar, whereas other gram-negatives grow as clear or whitish colonies.

Answer 97

The most important pathogenic attribute of the strains of E. coli that cause neonatal disease is the capsule. Most of the strains that cuase this have the K1 serotype.

Answer 98

Presentation – child with glucosuria, polyuria, polydipsia, and weight loss despite increased appetite

Answer 99

Pathophysiology – autoimmune destruction of the pancreatic islet β cells and, in many patients, an autoantibody is directed against glutamic acid decarboxylase (GAD65) which is an enzyme that is present in β cells. GAD65 is the largest component tested in the islet cell antibody test and a positive test is useful to distinguish between type 1 and 2 diabetes. Other features of type I diabetes mellitus include insulin deficiency, hyperglycemia, increased hemoglobin A1c, increased serum osmolarity and decreased C-peptide.

Answer 100

ECG usually first shows tall, peaked T waves, then prolongation of the PR interval, then absent P waves with widened QRS complexes and finally ventricular tachycardia/ventricular fibrillation.

Answer 101

Hyperkalemia Succinylcholine is a depolarizing skeletal muscle relaxant. It acts by binding to and stimulating nicotinic ACh receptors (Nm) at skeletal muscle motor end plates. Nm receptors are voltage-gated cation channels that allow Na+ in and K+ out of the cell. The constant depolarization produced by succinylcholine innitaly cases fascicultations, but then leads to mucle relaxation. In addition to hyperkalemia, this gagent is associate dwith malignant hyperthermia, prolonged paralysis, respiratory depression, cardiac arrhythmias, rhabdomyolysis and myoglobinemia.

Answer 102

increased serum calcium (hypercalcemia), relatively decreased urine calcium for the degree of hypercalcemia (relative hypocalciuria), slight hypermagnesemia, and normal/high levels of PTH (which are inappropriate for the degree of hypercalcemia.

Answer 103

* Decreases in sensitivity of calcium-sensing receptor (CaSR) have been implicated in several diseases including FHH, neonatal severe hyperparathyroididsm, and AD hypoparathyroidism. * CaSR is found in the parathyroid glands and plays a major role in calclium metabolism my mediated feedback inhibition of the secretion of PTH based on blood calcium concentration. It is also found in the kidney, where it mediates the feedback inhibition of PTH-indepednent calcium reabsorption in response to blood calcium concentration.

Answer 104

In ESRD, impaired phosphate secretion leads to hypocalcemia causing secondary hyperparathyroidism.

Answer 105

calcimimetic agent that incrases the sensitivity of the parathyroid calcium-sensing receptor (CaSR) on chief cells of the parathyroid gland to extracellular calcium, which causes a reduction in PTH. Indicated for management of secdonary hyperparathyroidism in patients with CKD and the treatment of hypercalcemia in patients with parathyroid carcinoma.

Answer 106

cinacalcet should not be administerd if calcium levels are below normal; this is the rationale for the administration phosphate binders (e.g., sevelamer, aluminum hydroxide, calcium slats) and vitamin D.

Answer 107

bisphosphonate that inhibits osteoclast activity, reducing bone resorption and turnover. Asosciated with the development of hypocalcemia. Indicated for treatment of malignant hypercalcemia and Paget disease.

Answer 108

most common form is caused by a deficiency of copper-dependent tyrosinase (tyrosine hydroxylase), blocking the procution of melanin from the aromatic amino acid tyrosine. Inherited in AR manner. Affected individuals lack melanin pigment in skin, hair, and eyes, and are prone to develop sun-induced skin cancers, including both SCC and melanomas.

Answer 109

Renal plasma flow (RPF) = RBF X (1 – HCT)

Answer 110

Glomerular oncotic pressure increases along the length of the glomerular capillary. The filtrate is normally protein free and the filtration process removes water, leaving behind the protein, which increases in concentration. This increases glomerular oncotic pressure and tends to lower the average net filtration pressure and hence GFR. When renal plasma flow is reduced, water is being removed from a smaller volue, resulting in a steep rise in onctic pressure along the glomerular capillary.

Answer 111

Vulnerable to the pickwickian syndrome in which the pressure from a fatty neck causes intermittent airway obstruction resulting in hypoxemia and respiratory acidosis. Acute respiratory acidosis is characterized by signficiant increases in PaCO2, reduced pH, and modestly increased bicarbonate. An increase of PaCO2, will, by the carbonic anhydrase-mediated reaction, cause an increase of the strong acid H+ and the weak base, bicarbonate. Thus, the acidity of the solution greatly increases even though the quanitity of base slightly increases.

Answer 112

Think Staph aureus (gram-positve, catalase-positive, coagulase-postive coccus). Treatmetn is with nafcillin or oxacillin. Other bacteria that commonly produce pneumonia in context of influenza include H. influenzae and Strep pneumoniae.

Answer 113

Whether ductal or lobular, it is associated with a significantly increased risk of breast carcinoma (5X). Sclerosing adenosis (increase in number of acini in background of fibrosis; distinguished from invasive carcinoma d/t presence of myoepithelial layer) and hyperplasia without atypia are associated with a slightly increased risk (2X).

Answer 114

NSAIDs are first-line unless previous HSR to NSAIDs → use colchicine Colchicine – inhibits leukocyte migration and phagocytosis secondary to an effect on MT assembly. AE include severe diarrhea, abdominal cramping, leukopenia, myelosuprresion and hepatotoxicity.

Answer 115

Managed by lowering uric acid levels. NOTE that the use of uric acid lowering agents in an acute setting may initially precipitate an acute attack! Probenecid and sulfinpyrazone – uricosuric agents that increase urinary excretion of uric acid; initiated 1-2 weeks after the acute attack has subsided if uric acid levels are elevated Allopurinol and febuxostat – xanthine oxidase inhibitors (i.e. inhibit enzyme that forms uric acid from hypoxanthine); initiated within 1 week of the acute attack if pt has elevated uric acid levels.

Answer 116

Balloon deflated – pulmonary artery pressure (pulsatile with systolic/diastolic values of 25/8) Baloon inflated – cathether is “wedged” in a small branch of pulmonary artery (pulmonary wedge pressure provides an indirect estimate of the left atrial pressure)

Answer 117

* Chylomicrons – lipoproteins that carry dietary TGs and cholesterol from intestine to the tissues * Produced by enterocytes (intestinal epithelial cells * Secreted into gut lymphatic system and drain eventually into systemic venous system from thoracic duct * Initially they are large, but with time LPL releases TGs from chylomicron core by hydrolyzing them to more easily absorbed FAs. LPL is found on the luminal surface of endothelial cells lining the capillaries.

Answer 118

Zones are based on blood flow Zone 1 = Periportal Zone; closest to the blood supply. Most susceptible to direct toxic injury (receives highest concentration from blood). Shows infiltration with hepatitis. Zone 2 = Intermediate Zone Zone 3 = Pericentral Vein Zone due to association with the terminal hepatic vein. Contains P450 oxidase enzyme system. Most susceptible to ischemic injury (furthest from blood supply) and injury by metabolites of drugs or other exogenous substances that might be acted on by the P450 system.

Answer 119

Rifampin = inhibits DNA-dependent RNA polymerase (nucleic acid synthesis inhibitor) Isoniazid = inhibits mycolic acid synthesis; prodrug requiring conversion by catalase. High level resistance deletions in katG gene (encodes catalase needed) for INH bioactivation Pyrazinamide Ethambutol = inhibits synthesis of arabinogalactan (cell-wall component); added if isoniazid resistance is suspected. Streptomycin = aminoglycoside; inhibits bacterial protein synthesis through irreversible binding to 30S RSU

Answer 120

Rifampin = hepatitis, induction of P450 (increased concomitant drug metabolism), red-orange metabolites Isoniazid = hepatitis (age-dependent), peripheral neuritis (use vitamin B6), sideroblastic anemia (use B6), SLE in slow acetylators (rare). Note that Vitamin B6 (pyridoxine) causes urine color to become a bright yellow. Pyrazinamide = hepatitis, hyperuricemia Ethambutol = dose-dependent retrobulbar neuritis causing decreased visual acuity and red-green discrimination Streptomycin = deafness, vestibular dysfunction, nephrotoxicity

Answer 121

Aspirated oral secretions in patients with compromised neuro status (e.g., anesthesia, coma, intoxication), or in individuals with a depressed cough reflex. Most common organisms isolated from lung abscesses include Bacteroides, Fusobacterium and Peptostreptococcus (all oral flora). CXR shows cavitary lesion with air-fluid level.

Answer 122

Babesia microti (causing a hemolytic anemia), or with Ehrlichia phagocytophilia (causing a febrile disease with leukopenia and thrombocytopenia), since these agents are transmitted by the same Ixodes tick vector.

Answer 123

Ductus arteriosus connects the left pulmonary artery to the aortic arch. During prenatal life, the pressure gradient causes blood to flow from the left pulmonary artery to the aorta. However, after birth, the pressure gradient reverses, and if the ductus arteriosus remains patent, the flow is from aorta to the left pulmonary artery --> pulmonary HTN

Answer 124

Severe, X-linked, abnormal dystrophin protein, loss of muscle cell membrane stability (some mutations result in complete absence of dystrophin expression, leading to DMD whereas other mutations may lead to partial expression of dystrophin, resulting in a less severe clinical form Becker muscular dystrophy) Falling and difficulty walking Pseudohypertrophy of calf muscles Gower's sign Increased risk of cardiomyopathy and arrhythmias

Answer 125

Pneumocystis jiroveci - exudate with foamy or honeycomb appearance - patchy infiltrative (ground glass appearance) on XR - surfactant-rich exudate (due to replication of type 2 pneumocytes) and silver-staining cysts in bronchial alveolar lavage fluids or biopsy - treatment is TMP/SMX

Answer 126

Characterized by ophthalmoplegia, pseudobulbar palsy, axial dystonia, and bradykinesia Widespread neuronal loss and gliosis in subcortical areas Sparing of the cerebral and cerebellar cortices

Answer 127

Because the airways are tethered to lung parenchyma, radial traction of the airways decreases when lung volume decreases, causing the airway diameter to decrease with each decrease in lung volume. The airways are tethered more strongly to the lung parenchyma in intersitital fibrosis, which causes the airways to be held open to a greater extent at each lung volume (i.e., radial traction is greater). This increase in radial traction and subsequent increase in airway diameter causes the maximum expiratory flow rate to be higher at any given lung volume

Answer 128

The increase in fibrous material in the lung causes the pulmonary compliance to decrease (increase elasticity) and inspiration is impaired. FEV1 decreases less than FVC, so the FEV1/FVC ratio is increased or normal.

Answer 129

Lower trunk of branchial plexus (C8-T1), which contributes to the formation of the ulnar and median nerves, leading to loss of function of all the intrinsic muscles of the hand supplied by these nerves. These include the interosseous muscles (abduction + adduction of digits) and opponens muscle (opposition of thumb).

Answer 130

Drugs = clomipramine, amitriptyline, imipramine, nortriptyline (TCA for elderly), desipramine MOA = block reuptake of NE and 5-HT AE = anticholinergic (muscarinic receptor blockade causes tachycardia, dry mouth, visual distrubances, mydriasis, urinary retention and constipation), alpha blockade, sedation, decreased seizure threshold, overdose (triad of 3 C's of coma, convulsions and cardiotoxicity; primary arrhythmias treated with sodium bicarbonate) and DDIs with MAOIs (fatal)

Answer 131

TCA used for OCD. Inhibits NE and seratonin reuptake, but also blocks muscarinic, histmaine H1 and alpha-1 adrenergic receptors.

Answer 132

Most aggressive tumor of astrocytic line (grade IV astrocytoma) Location: brain stem (children); cerebral cortex (adults). Often spread along white-matter tracts, especially the corpus callosum ("butterfly glioma") Pathology: tumor cells are pleomorphic, and frequently are bizarre in appearance with enlarged, abnormal nuclei. Show area of necrosis surrounded by rows of neoplastic cells (PSEUDOPALISADING NECROSIS)

Answer 133

Produce a fluent, receptive, or Wernicke's aphasia where patients cannot comprehend spoken language and have a fluent verbalization that lacks meaning ("word salad"), and reading and writing are similarly affected. Since this region of the temporal lobe also contains fibers of the visual radiations traveling to the primary visual cortex, can also present with right upper quadrantanopia ("pie in the sky"). REMEMBER - it would be a right visual field defect because Wernicke's is located in the left (dominant) hemisphere

Answer 134

Typically a late manifestation of AIDS (median CD4 count = 40) Usually an intermediate to high-grade B-cell lymphoma that typically involves the leptomeninges (often multicentric; "ring-enhancing mass lesions") Associated with EBV infections Sx: seizures, HA, CN deficits

Answer 135

Adamantinomatous CRANIOPHARYNGIOMA - these cells look very similar to cells that produce tooth enamel. This type commonly calcifies, which is visible on CT (cystic calcified parasellar lesion is likely to be a craniopharyngioma)

Answer 136

Remnants of Rathke's pouch - embryologic development of the pituitary involves both downward growth from the brain, forming the posterior lobe of the pituitary; and upward growth from the mouth (from remnants of Rathke's pouch) forming the anterior lobe of pituitary

Answer 137

Type of NTD where the brain herniates through a defect in the skull. The occipital bone is most common site.

Answer 138

MCC of dementia in elderly (memory loss, apraxia, confusion) Gross: cortical atrophy, widening of cerebral sulci, ventricular enlargement (hydrocephalus ex vacuo, due to loss of brain tissue), and atrophy of the medial temporal lobe (hippocampus, entorhinal cortex, amygdala). Microscopic: neurofibrillary tangles (NFTs), which are intracellular and neuritic (senile) plaques, which are extracellular plaques of amyloid

Answer 139

Microtubule-associated protein, tau. Normally tau binds to and stabilizes microtubules, thus aiding in the neuronal transport system. In AD, tau becomes hyperphosphorylated, cannot bind microtubles, and instead forms insoluble paired helical filaments, which are the primary components of the NFTs, leading to collapse of the neuron's transport system.

Answer 140

Medulloblastoma - primitive neuroectodermal tumor that is highly undifferentiated and originates from a primordial neuroglial precursor. Arise in cerebellar vermis which can cause truncal ataxia (vs. adult medulloblastomas more likely in cerebellar hemisphers). Can be positive for glial marker glial fibrillary acidic protein (GFAP)

Answer 141

Cause: Naegleria fowleri Sx: severe prefrontal HA, nausea, high fever, often an altered sense of smell; often fatal Transmission: free-living amebae picked up while swimming or diving in very warm or fresh water; penetrates cribriform plate and enters brain via olfactory nerves Dx: motile trophozoites in CSF; culture on plates seeded with gram negative bacteria (amebae will leave trails) Rx: Amphotericin B (rarely successful)

Answer 142

Site of Entry: Cavernous sinus Epidemiology: Affects DKA and cancer patients Sx: prefrontal headache, fever, sinusitis Path: hyphae branch at 90 degree angles and have irregular width Rx: debridement and amphotericin B; frequently fatal

Answer 143

HSV-1 which is specific to the temporal lobes of the brain. Can see Cowdry type A inclusions in neurons and glia. Diagnosis of viral encephalitis - elevated lymphocytes

Answer 144

Late complication of measles acquired when the patient is <2 y/o. Sx include changes in personality, behavior, and memory, myoclonic jerks, blindness, and spasticity. These may appear 6-7 years after clinical measles infection.

Answer 145

Ingestion of eggs of Taenia solium Swine serve as the intermediate host for the tapeworm; humans acquire the infection from the swine and become the definitive host. Once humans become infected, autoinfection with the larval cyst is possible. Epidemiology: Mexico, South Central America, Phillipines, Southeast Asia. Path: in the CNS, the cysts act as space-occupying lesions and cause hydrocephalus and/or seizures (focal or generalized). Signs of increased ICP such as HA, n/v, or visual changes may also be present.

Answer 146

Primary Brain Lymphoma or Cerebral Toxoplasmosis

Answer 147

Protozoan that infects humans who ingest the oocytes from cat feces or incompletely cooked lamb or pork. Only immunocompromised patients and fetuses are vulnerable to infection. Infections after birth are most commonly asymptomatic or mild; may mimic mononucleosis. In AIDS - ring-enhancing lesions in brain Fetus - severe congenital infections (intracerebral calcifications, chorioretinitis, hydro- or microcephaly, seizures).. Later term congenital infection may produce progressive blindness.

Answer 148

Late complication that affects the CNS, heart and skin. This stage of syphilis is characterized by formation of gummas (granulomas). Can be asymptomatic or can present as syphilitic meningitis (HA, meningeal irritation, CN abnormalities) mengiovascular syphilis (unilteral numbness, paresthesias, vertgio, weakness, personality changes), tabes dorsalis, or general paresis. Diagnosis - FTA-ABS and microhemagglutination

Answer 149

``` Mnemonic "paresis" Personality Affect hyperreactive Reflexes argyll-robertson pupils in the Eyes defects in the Sensorium Intellectual decline deficient Speech ```

Answer 150

Produced by the ciliary body and secreted into the posterior chamber of the eye --> flows through the pupil into the anterior chamber --> drains out of the eye via a trabecular meshwork and into the canal of Schlemm. If this angle is too narrow, as occurs with angle-closure (narrow angle) glaucoma, this circulation is obstructed and IP builds in eye, triggering glaucoma

Answer 151

Cause: closure of the preexisting narrow anterior chamber angle, as is commonly found in elderly, hyperopes, and Asians. Trigger: pupils dilate (e.g. when entering a dark room) or if taking an anticholinergic drug (e.g. scopolamine) Sx: intense pain and blurred vision (characteristically associated with halos around lights) S: eye is very red and steamy, and the pupil is dilated and nonreactive to light; tonometry reveals elevated IOP Tx: acetazolamide is first-line and should be used systemically immediately. It reduces bicarbonate production in the ciliary epithelium, thus decreasing aqueous humor production. Mannitol is another agent used systemically to decrease IOP. Topical timolol (beta-blocker), apraclonidine (alpha-2 agonist) and pilocarpine (muscarinic agonist) can also be used.

Answer 152

"Halothane Hepatitis" - known to cause hepatic failure as well as malignant hyperthermia, cardiac arrhythmias and BP changes. The severity of the hepatic dysfunction can vary from an asymptomatic elevation in serum transaminases to fulminant hepatic necrosis.

Answer 153

Sumatriptan - 5-HT1B/D agonist. Can cause significant elevations in BP including hypertensive crises (contraindicated in patients with HTN) Ergotamine - partial agonist/antagonist activity at the tryptaminergic, dopaminergic, and alpha-adrenergic receptors. Toxic effects include cyanosis, absence of peripheral pulse, cold extremities, and potentially gangrene. Contraindicated in patients with Prinzmetal angina. Can produce mild hypo- or hypertension but is not associated with hypertensive crisis.

Answer 154

Compliance = Change in Volume / Change in Pressure. OR otherwise stated, the pulse pressure (ΔP) is predicted by the compliance equation where ΔP = ΔV/C, where ΔV is the stroke volume.

Answer 155

Either an increase in SV or a decrease in compliance. In older adults, the pulse pressure sometimes increases as much as 2X normal because the arteries become hardened by arteriosclerosis and compliance thus decreases.

Answer 156

High compliance means the blood vessels are more easily distended by blood. A decrease in arterial compliance, such as that caused by arteriosclerosis, indicates that the arterial wall is stiffer (i.e., less distensible). Will cause an increase in systolic pressure and a decrease in diastolic pressure, leading to a widened (i.e. increased) pulse pressure (SP-DP=PP).

Answer 157

BMD - X-linked recessive inheritance or spontaneous. Milder; patients may walk until age 20-25. DMD - severe X-linked, abnormal dystrophin protein, loss of muscle cell membrane stability. Elevation of CK and histologic degeneration precedes clinical features. * pelvic girdle weakness and ataxia * course is progressive, children unable to walk by age 10 * pseudohypertrophy of calves is characteristic * myocardial muscle involvement accompanies other muscle degeneration; may cause death * heterozygous female carriers have subclinical degeneration of muscle fibers

Answer 158

MG - autoimmune disease with antibodies against NMJ AChR. Typically affects young women with fluctuating weakness but no sensory abnormalities; worsens with increased use of muscles. Diagnosis via decremental response on EMG or improvement with edrophonium. May have thymic abnormalities including thymoma (10-20%) or thymic hyperplasia (70-89%). LE - closely linked to MG with similar symptoms. Autoantibodies are directed against NMJ Ca2+ channels. May occur in a paraneoplastic setting.

Answer 159

Acetylcysteine - replenishes the glutathione needed to enhance the metabolism of this drug to a non-hepatotoxic metabolite. Acetaminophen toxicity causes nausea, vomiting and abdominal pain.

Answer 160

Atropine + pralidoxine (for irreversible AChE inhibitors)

Answer 161

Deferoxamine

Answer 162

Digoxin immune F (ab)

Answer 163

Dimercaprol (BAL). Can use oral succimer for milder lead and mercury toxicity. EDTA can be used as a backup in lead poisoning.

Answer 164

Ethanol or Fomepizole

Answer 165

Flumazenil S/Sx of BZD toxicity include confusion, dizziness, blurred vision, drowsiness, unresponsiveness, anxiety, nystagmus, ataxia, slurred speech, hypotonia and amnesia. The majority of BZDs end in "lam" or "pam" except chlordiazepoxide

Answer 166

Penicillamine

Answer 167

Physostigmine

Answer 168

Bicarbonate - used to alkaline the urine and enhance the excretion of acidic drugs (e.g., aspirin). Overdose of aspirin will usually cause hyperventilation and tinnitus. Bicarbonate is also used for arrhythmias and hypotension in TCA overdose (characterized by the 3 C's = convulsions, coma, cardiotoxicity)

Answer 169

Caused by the introduction of bacteria into the bloodstream. Can be produced either by LPS, which is present in the cell wall of all gram-negative bacteria, or by certain toxins released by gram-positive bacteria and fungi. LPS binds to a serum protein and stimulates CD14 receptors on endothelial cells and circulating inflammatory cells, eliciting a broad range of end-organ responses. Manifests as decreased BP, tachycardia and skin that is warm and flushed. Often associated with DIC and usually leads to multiple organ failure.

Answer 170

Severe CNS malformations (arhinencephaly and holoprosencephaly), growth retardation, severe mental retardation, sloping forehead, microphthalmia, cleft lip and palate, and polydactyly. Death within 1 year of birth. Least common form of viable autosomal tirsomy.

Answer 171

Passes around the neck of the fibula, where it is susceptible to injury. Just distal to the neck of the fibula, the common fibular nerve divides into 2 main branches, the superficial fibular nerve (supplies most of the skin of the dorsum of foot; in addition to the lateral muscles that evert the foot) and the deep fibular nerve (supplies muscles that dorsiflex the foot, extend toes, and assist in foot inversion; also supplies patch of skin in first web space).

Answer 172

Acute generalized infarction of cortices of both kidneys with relative sparing of the medulla. Likely due to a combination of hypotension, vasoconstriction and microthrombi from DIC. Associated with septic shock and obstetric catastrophes (e.g., abruptio placentae, amniotic fluid embolism, retained placenta). Clinically presents with acute renal failure: acute onset of oliguria, anuria, and uremia.

Answer 173

The middle meningeal artery is a branch of the maxillary artery. It enters the cranial cavity through the foramen spinosum and is located in the floor of the middle cranial fossa. Tear of the middle meningeal artery results in accumulation of blood between the inner table of the skull and dura mater (EPIDURAL HEMATOMA) where pt presents with a lucent interval (i.e. after the inital concussion causes unconscioussness, the patient regains consciousness and appears lucid). Because the dura is firmly attached ot the skull at the suture lines, an epidural hematoma will not spread past a suture line, resultign in the biconvex accumulation of blood. May lead to herniation of the uncus of the temporal lobes around the edge of the tentorium. The uncus will then compress the midbrain in teh region of hte oculomotor nerve reuslting in a dilated pupil and loss of consciousness.

Answer 174

The superior ophthalmic vein, which communicates between the cavernous sinus and veins of the orbit and face. In addition, all of the cranial nerves that innervate the extraocular muscles (CN III, IV, and VI) pass through this fissure along with the ophthalmic division of the trigeminal nerve (CN V1)

Answer 175

Radial Nerve - provides innervation to muscles in the posterior compartment of forearm, as well as the triceps muscle. These muscles play a critical role in extension of the digits and of the wrist, thus injury produces WRIST DROP. The supinator muscle also receives input from the radial nerve, thus patients may also have WEAKNESS WITH SUPINATION. Provides sensation to the proximal dorsal aspect of the thumb and lateral 3.5 digits.

Answer 176

Needle is inserted at L4-L5 interspace (cord ends at L1 or L2) where the subarachnoid space contains the nerve roots of the cauda equina floating freely in CSF. Epidural Anesthesia - anesthetic in epidural space Spinal Anesthesia - anesthetic into CSF in subarachnoid space Skin --> Superficial Fascia --> Deep Fascia --> Supraspinous Ligament --> Interspinous Ligament --> Flavum Ligamentum ---> Epidural Space --> Dura --> Arachnoid --> Subarachnoid Space

Answer 177

Paralysis of the entire side of the face indicates an ipsilateral LMN lesion of CN 7. Paralysis limited to the lower half of the face indicates a contralateral UMN lesion. The reason for this is that the corticobulbar innervation to muscles of the upper face is bilateral; the corticobulbar innervation of facial nucleus motorneruons innervating the lower face is only contralateral.

Answer 178

The chorda tympani branch of CN 7 passes through the middle ear cavity and can be injured during surgery. It contains preganglionic parasympathetic fibers that synapse in the submandibular ganglion. Postganglionic fibers innervate the submandibular and sublingual glands. The chorda tympani also carries special sensory fibers for taste from the anterior 2/3 of tongue. Parotid gland is innervated by the postganglionic parasympathetic nerve fibers from the otic ganglion which receives its preganglionic parasympathetic nerve fibers from the lesser petrosal branch of CN 9.

Answer 179

Need to avoid tyramine-containing foods (e.g., cheese, wine and beer) to prevent a sympathetic (or hypertensive) crisis. Mechanism: When a patient is on an MAOI, GI and hepatic MAO is inhibited, thus allowing large quantities of ingested tyramine to reach the systemic circulation where it enters synaptic terminals of postganglionic sympathetic neurons and displaces massive amounts of NE. Neuronal MAO is also inhibited, so that the released NE cannot be metabolized. Other RXNs: MAOIs can interact with SSRIs, TCAs, meperidine, St. John's wart, and dextromethorphan to produce a serotonin syndrome. MAOIs: phenelzine, tranylcypromine, isocarboxazid

Answer 180

Dopamine is preferentially metabolized by MAO-B, therefore dopamine levels will rise if MAO-B is inhibited. MAO-B inhibitors include selegiline and rasagiline. In contrast, MAO-A preferentially metabolizes NE and 5-HT. Parkinson disease is caused by DA depletion resulting from degeneration of nigrostriatal neurons. MAO-B inhibitors are often used as monotherapy for early symptomatic treatment of PD d/t their better AE profiles and ability to improve long-term outcomes.

Answer 181

Delirium is a common complication. It is characterized by acute changes (days to weeks) in mental status with fluctuating level of consciousness, agitation, irritability and psychosis. Patients usually respond to low-dose neuroleptics (e.g. risperidone) to achieve sedation. Contrast to Dementia, which would be characterized as chronic over months to years, disorientation to person, remote memories seen as recent, less common hallucinations, less sleep disruption, mostly irreversible, attention span not reduced)

Answer 182

GAD - characterized by excessive anxiety and worry. Anxiety and worry are associated with at least 3 of the following Sx: irritability, muscle tension, sleep disturbances, restlessness, difficulty concentration, and easy fatiguability. Treatment - Buspirone is a nonbenzodiazepine anxiolytic agent that is nonsedating, is not associated with tolerance or dependence, does not interact with benzo receptors or alcohol, has no abuse potential, and does not cause sexual dysfunction. Other FDA approved drugs include venlafaxine, escitalopram, paroxetine, and fluvoxamine.

Answer 183

Blockade of dopamine 2 (DA2) receptors are largely responsible for both the antipsychotic effects (via mesolimbic/mesocortical pathways) and EPS (via nigrostriatal pathways) of typical antipsychotic drugs. DA2 receptors are coupled to Gi proteins, which inhibit AC and decrease cAMP production when stimulated. Thus blockade of receptors will produce increase in cAMP production.

Answer 184

Gq = activates PLC (increases IP3 and Ca2+, DAG); alpha1, M1, M3 Gi = inhibition of AC (decrease cAMP); alpha 2, M2, D2 Gs = stimulation of AC (increase cAMP); B1, B2, D1

Answer 185

Bupropion - indicated for treatment of major depressive disorder as well as smoking cessation. Should not be prescribed to patients with bulimia or anorexia because of the increased risk of seizures secondary to metabolic disturbances. Fluoxetine is the only antidepressant currently approved for the treatment of bulimia.

Answer 186

Methysergide - can cause n/v; BBW for retroperitoneal fibrosis, pleuropulmonary fibrosis, and fibrotic thickening of cardiac valves

Answer 187

In chronic CHF, stagnation of blood in the venous system (backward failure) leads to chronic passive congestion and results in centrilobular necrosis of the liver. This can cause sinusoidal rupture with central hemorrhagic necrosis. Appearance = "Nutmeg Liver" Remember - centrilobular zones (aka pericentral zones or zone III) are located closest to the central veins of the liver, which drains into the hepatic veins and ultimately into systemic circulation. They also contain P450 metabolism system. Most vulnerable to necrosis from venous stasis, ischemic damage, toxic injury (acetaminophen, alcohol, etc), and acute cellular rejection during liver transplant. In contrast, periportal zones (zone I) are closest to the portal triads that are most likely to be the first necrotic regions in viral hepatitis.

Answer 188

Addison Disease (adrenal insufficiency; AI destruction of adrenal cortex with decreased secretion of cortisol, aldosterone, and adrenal androgens): 1) hypotension and weakness, 2) increased skin pigmentation (d/t increased ACTH secondary to loss of negative feedback inhibition by cortisol), 3) hyperkalemia Conn Syndrome (hyperaldosteronism): 1) HTN, 2) hypernatremia, 3) hypokalemia

Answer 189

The genioglossus muscle is responsible for protrusion of the tongue. It is supplied by the hypoglossal nerve. Paralysis results in deviation toward the side of the lesion. NOTE - Hypoglossus muscles (innervated by hypoglossal nerves) function to retract the tongue. Palatoglossus muscles (innervated by vagus) function to pull tongue back (retract) and upward toward the palate.

Answer 190

Tyrosine kinase activity. Insulin binding to its receptor activates the cytoplasmic tyrosine kinase domain, causing autophosphorylation of the receptor. These phosphotyrosine residues initiate the signal transduction pathways associated with insulin. PTP1B (protein tyrosine phosphatase) opposes insulin signaling by dephopshorylating the phosphotyrosine residues of the insulin receptor, blocking further signal tranduction. A mouse lacking PTP1B activity would show an increased hepatic response to insulin. If tyrosine kinase activity is increased (e.g., by knocking out PTP B1), several rate-limiting enzymes in anabolic pathways will have increased activity. Rate-limiting enzymes in catabolic pathways will have decreased activity.

Answer 191

Acetyl-CoA carboxylase, which catalyzes the rate-limting step in fatty acid biosynthesis.

Answer 192

Acute salicylate poisoning stimulates the respiratory centers and causes acute respiratory alkalosis. This initial response is often followed by metabolic acidosis, potentially with respiratory failure. Davenport Diagram: pure respiratory alkalosis moves the point downward and to the right along the constant metabolic acid/base buffer line that goes through the normal point.

Answer 193

CAUSE - vitamin D def due to chronic renal insufficiency, intestinal malabsorption, or dietary deficiency; osteoid produced in normal amounts but not calcified properly (diffuse radiolucency on bone films); low calcium and phosphorus and high alkaline phosphatase. Rickets - children, prior to closure of the epiphyses. Bone deformities, "rachitic rosary" (deformity of the chest wall), bowing of legs, and fractures. The hallmark is widened osteoid due to poor mineralization of bone. There are increased number of osteoblasts, which lay down increased quantities of osteoid in an effort to strengthen the bone. Unfortunately, the increased osteoid is not mineralized and bone remains soft and weak. Osteomalacia - impaired mineralization of normal osteoid matrix, fractures, deformities

Answer 194

``` Immediate Antibody: IgE Complement: No Effector Cells: Basophil, mast cell Examples: Hay fever, atopic dermatitis, insect venom sensitivity, anaphylaxis to drugs, some food allergies, allergy to animals and animal products, asthma ```

Answer 195

Cytotoxic Antibody: IgG and IgM Complement: Yes Effector Cells: PMN, macrophages, NK cells Examples: autoimmune or drug-induced hemolytic anemia, transfusion reactions, Hemolytic Disease of Newborn, hyperacute graft rejection, Goodpasture disease, rheumatic fever, Bullous pemphigoid

Answer 196

``` Noncytotoxic Antibody: IgG Complement: No Effector Cells: None Examples: Myasthenia gravis, Graves disease, Type 2 DM ```

Answer 197

``` Immune Complex Antibody: IgG, IgM Complement: Yes Effector Cells: PMN, macrophages Examples: SLE, RA, polyarteritis nodosa, poststreptococcal glomerulonephritis, Arthus reaction, serum sickness ```

Answer 198

Delayed HSR: develops in response to viral, fungal, and intracellular bacterial antigens. It involves CD4 T-helper lymphocytes, but not antibody! Antibody: None Complement: No Effector Cells: CTL, TH1, macrophages Examples: Tuberculin test, tuberculosis, leprosy, Hashimoto thyroiditis, poison ivy (contact dermatitis), acute graft rejection, GVHD, Insulin-dependent Diabetes Mellitus

Answer 199

Type II HSR in which antibody is produced against cells or receptors in the body. In this type of cytotoxic disease, the mother produced antibody against Rh+ cells to which she was exposed upon delivery of first child. There is no problems during the first pregnancy because the mother's immune system will not usually encounter fetal blood cell antigens until placental seperation at time of birth. However at that time, Rh+ fetal RBC enter maternal circulation and stimulate T-dependent immune response, generating memory B cells capable of producing IgG antibody against RhD. In subsequent pregnancy with another Rh+ fetus, this maternal IgG can be transported across placenta, react with fetal Rh+ red cells, and activate complement, producing hemolytic disease in the newborn (jaundice and HSM)

Answer 200

Treat Rh- mother with RhoGAM, a preparation of human anti-RhD IgG antibody at 28 weeks and within 72 hours after birth. This antibody effectively eliminates the fetal Rh+ cells before they can generate RhD-specific memory B cells in the mother. Anti-RhD antibody should be given to an Rh- individual following any termination of pregnancy.

Answer 201

Type I immediate HSR that occurs in minutes following exposure to the offending allergen. Initial Exposure to Antigen: B cell-mediated reaction that causes the proliferation of IgE. The IgE links to the Fc portion of mast cells and basophils. Re-Exposure to Antigen: IgE cross links and causes degranulation of mediators such as histamine, leading to an immediate HSR. Antigen: ragweed, tree pollen, grass pollen, animal fur, or food products.

Answer 202

Produces a chronic granulomatous disease with caseating granulomas. Most cases occur in 4 states (Texas, Cali, Virginia, Florida) and are associated with cattle, in which it produces spontaneous abortions. Most cases produce mild disease or fevers of unknown origin. However, can infect cardio system and cause endocarditis (aortic > mitral valve).

Answer 203

Dimoprhic fungal disease that produces a granulomatous pulmonary syndrome that is more severe in dark-skinned. Disseminated disease occurs most often in Filipinos, Mexicans, and Africans. The infective form is the athrospore; the diagnostic form in tissue is the spherule containing endospores. The disease is endemic in San Joaquin River Valley. At risk groups include military personnel, agricultural/construction/oil-filed workers, archaeology students, participants in outdoor sports, and sightseers. Remote infections from fomites (i.e., cotton harvested in the Southwestern US) have been reported.

Answer 204

More common in women (20-60 y/o) d/t AI rxn with formation of circulating antibodies (rheumatoid factor). Starts in small joints in hands and feet but may involve any joint; usually symmetric involvement. Sx - low grade fever, malaise, fatigue, and morning stiffness Physical - joint swelling, redness, and warmth Synovial fluid - increased cells (usually neutrophils) and poor mucin Elevated ESR and hypergammaglobulinemia XR - erosions and osteoporosis Swan-neck deformity (PIP joints hyperextended and DIP joints flexed), enlarged knuckles, and subcutaneous nodules. The subcutaneous nodules are composed of areas of fibrinoid necrosis surrounded by palisading epithelioid cells. Fibrinoid necrosis is commonly associated with vasculitis, AI disease, malignant HTN, and preeclampsia. It reflects deposition of immune complexes in the vessel walls, causing swelling of the media and intensely eosinophilic staining of material resembling fibrin.

Answer 205

Superantigens (e.g. exotoxin TSST-1 of staph aureus) - viral or bacterial proteins that crosslink the T-cell receptor to an MHC II molecule. Crosslinking induces T-cell activation and proliferation without specific antigen recognition of peptide in the MHC II groove. Result in polyclonal activation and production of dangerous amounts of cytokines including IL-1, IL-6, and TNF-alpha from macrophages, and IL-2 and IFN-gamma (from TH1 lymphocytes).

Answer 206

Median nerve is comprssed as it passes underneath teh flexor retinaculum of the wrist. Many conditions predispose including hypothyroidism, pregnancy, amyloidosis, acromegaly, obesity, diabetes, and work with vibrating tools. Thenar wasting is suggestive of median nerve lesion due to loss of innervation to the thenar muscles: abductor pollicis brevis, opponens pollicis, and flexor pollicis brevis. Median nerve supplies sensation to lateral two-thirds of palm, from the thumb to the lateral half of the fourth (ring) finger. Also supplies distal dorsal surface of these fingers. NOTE: palm sensation is not affected by carpal tunnel syndrome; the superficial palmar cutaneous branch of median nerve passes superficial to the carpal tunnel.

Answer 207

Mesoderm of the dorsal mesentery of the stomach (dorsal mesogastrium). It is not a foregut structure, nor is it derived from endodermal epithelium. The celiac artery supplies all the foregut organs (part of the gut tube from the respiratory diverticulum, which marks the end of the pharynx, to the hepatic diverticulum, which marks the end of the foregut) and the spleen. The celiac artery arises from the abdominal aorta immediately below the aortic hiatus of the diaphragm, which is at the T12 vertebral level.

Answer 208

The inferior and superior pancreaticoduodenal arteries freely anastomose (within the head of the pancreas), effectively connecting the SMA withe celiac trunk. The superior pancreaticoduodenal artery is a branch of the gastroduodenal artery, which is a branch of the common hepatic artery, itself a branch of the celiac trunk. The inferior pancreaticoduodenal artery is a branch of the SMA.

Answer 209

Works primarily by inhibiting the enzyme peroxidase, which is located in the apical border of the follicle cell, and catalyzing oxidation of iodide to iodine. This is the first step in thyroid hormone biosynthesis after iodide uptake. Peroxidase also catalyzes iodination of tyrosyl residues (organification) on thyroglobulin to from MIT and DIT, and coupling of MIT and DIT to form T3 and T4, which are also inhibited by PTU. NOTE - PTU cannot be used as an acute symptomatic treatment measure for hyperthyroidism. BBs (propranolol and atenolol) are drugs of choice for this.

Answer 210

PTU is associated with the development of agranulocytosis. PTU also has a low incidence of causing severe hepatic dysfunction, including the development of encephalopathy and fulminant hepatic necrosis. When patients are unable to tolerate antithyroid medications, radioactive iodine (I-131) therapy and/or surgical resection is indicated.

Answer 211

Propranolol is a nonselective beta-adrenergic receptor antagonist that may also mildly block conversion of T4 to T3. BBs can be used before, during, and after RAI therapy without interfering with radioiodine uptake into the thyroid gland. BBs such as propranolol and atenolol are the drugs of choice for symptomatic therapy to improve adrenergic symptoms (tachycardia, tremor, and anxiety). If BBs are contraindicated, diltiazem or verapamil can be used.

Answer 212

Muscles tested are the gluteus medius and gluteus minimus, whose abductor actions allows them to hold the pelvis over the leg planted on the ground while raising the other leg. The sign is present if the pelvis drops on the side OPPOSITE to the stance leg, while the opposite limb is off the ground. The muscles being tested are on the side of the stance limb while the side of the pelvis that is observed is on the opposite side.

Answer 213

The gluteus medius and minimus are innervated by the superior gluteal nerve, which contains nerve fibers from spinal levels L4, L5, and S1. Positive signs can be seen in some polio victims who have had destruction to anterior horn cells at these levels. Other causes of positive signs include disc herniations at low lumbar levels and intragluteal injections that cause injury to the superior gluteal nerve.

Answer 214

Lower PO2, Higher PCO2, Lower pH (tissues produce CO2, which makes carbonic acid, and thus causes the venous blood to be slightly more acidic than arterial blood).

Answer 215

Both are examples of the effects of a deletion in an area affected by imprinting. A minority of cases are caused by uniparental disomy. Angelman - deletion of 15q11-q13 in mother. "Happy Puppet Syndrome," always smiling but lacks speech, hyperactive and hypotonic, mental retardation, seizures, dysmoprhic facial features, ataxic/puppet-like gait Prader-Willi - deletion of 15q11-q13 in father. Short stature and obese with small hands and feet, hyperphagia, dysmoprhic facial features, mental retardation, delayed psychomotor development (late walking), hypogonadism

Answer 216

Longest when left ventricular volume is maximal (end diastolic volume). This occurs just before left ventricular contraction. Conversely, sarcomere length is shortest at the end of systole when the volume of the left ventricle is lowest (end systolic volume). When the venous return to the heart increases, the end diastolic volume increases (increased preload), and thus sarcomere length increases.

Answer 217

K-complex (high-amplitude single spike followed by a trough) as well as sleep spindles (very high-frequency burst). Stage 2 sleep has more theta waves than stage 1.

Answer 218

In PTSD there is re-experiencing of the event (in the form of recurrent, intrusive recollections, flashbacks, and nightmares) and avoidance of associated stimuli. The symptoms last for >1 month, but after symptoms abate, they are usually followed by complete recovery. Note that if symptoms last <1 month it is diagnosed as acute stress disorder.

Answer 219

"DIG FAST" Distractibility (inability to concentrate) Indiscretion/irresponsibility (pleasure seeking without regard to consequences) Grandiosity (inflated self-esteem) Flight of ideas (racing thoughts) Activity increase (increase in goal-direct activity)/Agitation Sleep (decreased need) Talkativeness (pressured speech)

Answer 220

Typically a middle-aged, obese male who snores loudly during sleep. The problem stems from obstruction by tissues of the nasopharynx and hypopharynx. The obstruction results in significant periods of apnea associated with arterial hypoxemia and bradycardia. The patient may develop both systemic and pulmonary HTN, and is at high risk of sudden death during sleep due to severe hypoxemia and arrythmias. Often the patient with have a long apneic period followed by gasping respirations and awakening. Patient gets little sleep and results in daytime somnolence. Polysomnogram reveals decrease in stage 3 and REM sleep.

Answer 221

Initial treatment is weight loss, with a trial of nasal-prong or face-mask continuous positive airway pressure (CPAP).