Uworld30 Flashcards
1
Q
What is xeroderma pigmentosum?
A
develops due to a defect in nucleotide excision repair. This disease is characterized by increased sensitivity to ultraviolet radiation and a high incidence of cutaneous malignancy
2
Q
What is the Romberg test?
A
a test of proprioception in which patients are observed for unsteadiness as they stand with their feet close together, arms to the sides, and eyes closed.
Failure to maintain this posture indicates sensory ataxia, which may be caused by defects in the posterior column or peripheral nerves (eg, tabes dorsalis, vitamin B12 def)
3
Q
What is a bicuspid aortic valve?
A
a common cause of aortic stenosis in the US.
The classic auscultation of aortic stenosis is a harsh, crescendo-decrescendo systolic ejection murmur best heard at the right upper sternal border with radiation to the carotids.
4
Q
What is cerebral palsy?
A
a non progressive neurologic injury that most commonly presents with delayed gross motor milestones, spasticity, and hyperreflexia. Premature infants are particularly susceptible due to periventricular leukomalacia (white matter necrosis)
5
Q
In chronic obstructive pulmonary disease, air trapping leads to?
A
an increase in residual volume and total lung capacity, and increase in RV/TLC ratio.
Airway obstruction causes a decrease in forced vital capacity, forced expiratory volume in 1 second, and the FEV1/FVC ratio.
6
Q
What is IgA nephropathy (Berger disease)
A
frequently presents as recurrent, self limited, painless hematuria; episodes often occur concurrently with an upper respiratory tract infection.
Kidney biopsy will show mesangial IgA deposits on immunofluorescence.
In contrast, poststreptococcal glomerulonephritis is seen 1-3 weeks after streptococcal pharyngitis and is usually not recurrent.
7
Q
Pancreatic zymogens are normally converted into their active for by?
A
trypsin in the duodenal lumen.
Premature cleavage of trypsinogen to trypsin within the pancreas leads to uncontrolled activation of these zymogens, causing pancreatic autodigestion and acute pancreatitis.
8
Q
MOA of 5-alpha reductase inhibitors (eg, finasteride, dutasteride)
A
block the conversion of testosterone to dihydrotestosterone in the prostate. These drugs reduce prostate volume in patients with benign prostatic hyperplasia and relieve the fixed component of bladder outlet obstruction.
9
Q
Warfarin inhibits?
A
proteins C and S (natural anticoagulant present in blood), which can lead to skin necrosis, particularly in patients with protein C or S deficiency. This complication is usually seen in the first few days of warfarin therapy.
10
Q
What is ductal carcinoma in situ?
A
The terminal duct lobular unit is the functional unit of the breast and the site of origin for most breast carcinomas.
Ductal carcinoma in situ is characterized by neoplastic epithelial cells (sometimes with pleomorphism and central necrosis) that fill the ducts/lobules.
11
Q
What is trazodone?
A
a highly sedating antidepressant commonly used to treat insomnia.
Priapism is a rare but serious adverse effect.
12
Q
What is responsible for biliary stones in patients with somatostatinoma?
A
Reduced gallbladder contractility, due to decreased cholecystokinin secretion, is responsible for biliary stones in patients with somatostatinoma.
13
Q
What is colonic diverticula?
A
often involve the sigmoid colon and develop due to exaggerated contractions of colonic smooth muscle segments.
This results in increased intraluminal pressure, causing outpouching of the mucosa and submucosa through the muscularis (false diverticula).
Individuals (typically age>60) may be asymptomatic or have hematochezia or diverticulitis.
14
Q
What is the difference between duodenal ulcers and ones in the stomach?
A
Duodenal ulcers are not associated with an increased risk of carcinoma in the same location.
In contrast, ulcers located in the esophagus, stomach (gastric), and colon may be malignant, and biopsy is required.
15
Q
Where does the testes and scrotum drain?
A
Due to its intra-abdominal origin, lymphatic drainage of the testis is to the para-aortic lymph nodes.
Lymph drainage from the scrotum goes into the superficial inguinal lymph nodes.
16
Q
Drug induced parkinsonism is an extrapyramidal side effect caused by meds that?
A
block D2 receptors (eg, antipsychotics).
Management strategies include decreasing or discontinuing the offending medication and treatment with an anticholinergic medication.
17
Q
What is correlation analysis?
A
a statistical technique used to describe the strength and direction of a linear relationship between 2 quantitative variables.
18
Q
What is diverticulitis?
A
characterized by inflammation of colonic diverticula. Patients have abdominal pain, nausea, vomiting, and changes in bowel habits. Low grade fever and leukocytosis are common, and physical examination may demonstrate a tender mass in the left lower quadrant.
19
Q
What is xeroderma pigmentosum?
A
an autosomal recessive disorder characterized by defective nucleotide excision repair often caused by a deficiency in UV-specific endonuclease.
Affected children usually have severe photosensitivity, hyperpigmentation in sun-exposed areas, and a greatly increased risk for skin cancer.
20
Q
What alzheimer disease?
A
a progressive dementia featuring diffuse cortical atrophy involving loss of cholinergic neurons.
Memory, cognitive, and functional impairments of AD are partially mediated by insufficient cholinergic output.
Cholinesterase inhibitors (eg, donepezil) enhance cholinergic neurotransmission to compensate for this defect.
21
Q
The rubber-like properties of elastin are due to?
A
high content of nonpolar (hydrophobic) amino acids and extensive cross-linking between elastin monomers facilitated by lysyl oxidase.
Patients with alpha-1 antitrypsin deficiency can develop early onset, lower lobe predominant emphysema due to excessive alveolar elastin degradation.
22
Q
What is central hypothyroidism?
A
low serum TSH and thyroxine (T4) levels and is due to hypothalamic-pituitary dysfunction.
23
Q
What is Sheehan syndrome?
A
ischemic necrosis of the pituitary gland and is typically caused by systemic hypotension during delivery.
In addition to central hypothyroidism, patients may also develop deficiencies of other pituitary hormones (eg, ACTH, prolactin, gonadotropins).
24
Q
What is the paired t-test?
A
compares with mean of 2 related groups. The test requires that a quantitative dependent variable (ie, outcome) be evaluated in 2 related (ie, matched, paired) groups.
25
What is refeeding syndrome?
occurs after the reintroduction of carbohydrates in patients with chronic malnourishment, which stimulates insulin secretion and drives phosphorus intracellularly in an effort to maintain cellular energy metabolism (eg, ATP production); this redistribution of phosphorus can result in severe hypophosphatemia.
26
Acute cardiogenic pulmonary edema results from?
increased pulmonary venous pressure. The alveolar capillaries become engorged with blood and there is a transudation of fluid plasma across the alveolar-capillary membrane, appearing pink, acellular material within the alveoli.
27
What is oral (PO) bioavailability?
is calculated by dividing the area under the PO curve by the area under the IV curve.
Bioavailability refers to the fraction of administered drug that reaches the systemic circulation. For a drug administered by any route other than IV, bioavailability is usually less than 100%.
28
What is the second most common cause of severe combined immunodeficiency?
autosomal recessive deficiency of adenosine deaminase, an enzyme necessary for the elimination of excess adenosine within cells.
Toxic levels of adenosine accumulate within lymphocytes in this condition, leading to lymphocyte cell death and resultant cellular and humoral immunodeficiency. Patients with this condition can be treated with hematopoietic cell transplantation or gene therapy.
29
What is bronchopulmonary dysplasia?
common in premature infants due to arrest of fetal lung development in the saccular stage.
histo: impaired alveolarization (ie, dilated alveoli with decreased septation) and abnormal vasculogenesis (ie, dysmorphic alveolar capillaries)
30
What is multiple sclerosis?
an autoimmune disorder of the central nervous system characterized by recurrent episodes of demyelination, leading to reduced saltatory conduction.
Internuclear ophthalmoplegia and optic neuritis are common manifestations.
31
What is the function of LH and FSH in men?
LH stimulates the release of testosterone from the Leydig cells of the testes; FSH stimulates the release of inhibin B from the Sertoli cells in the seminiferous tubules.
Testosterone and inhibin B induce negative feedback on LH and FSH production, respectively.
32
The release of prolactin is under inhibitory control by?
dopamine secretion from the hypothalamus. Disruption of dopaminergic pathways or blockade of dopamine D2 receptors can cause hyperprolactinemia.
33
What is antiphospholipid antibody syndrome?
Many patients with systemic lupus erythematosus have antiphospholipid antibodies, which can cause paradoxical PTT prolongation and false-positive RPR/VDRL results; antiphospholipid antibody syndrome is characterized by arterial or venous thrombosis and increased obstetric morbidity (eg, recurrent pregnancy loss)
34
What is Osler-Weber-Rendu syndrome (hereditary hemorrhagic telangiectasia)?
an autosomal dominant condition marked by the presence of telangiectasias in the skin as well as the mucous membranes of the lips, oronasopharynx, respiratory tract, gastrointestinal tract, and urinary tract.
Rupture of these telangiectasias may cause epistaxis, gastrointestinal bleeding, or hematuria.
35
MOA of ipratropium
Ipratropium, an anticholinergic agent and derivative of atropine, treats obstructive lung disease by blocking acetylcholine at muscarinic receptors, which prevents bronchoconstriction and reduces mucus secretion from tracheobronchial submucosal glands.
36
What is depersonalization/derealization disorder?
a dissociative disorder involving recurrent episodes of feeling detached from one's body or surroundings and/or feelings of unreality.
37
What is the treatment of organophosphate poisoning?
Organophosphates inhibit acetylcholinesterase, leading to symptoms of muscarinic and nicotinic (neuromuscular dysfunction) cholinergic hyperstimulation.
Management includes atropine, a competitive inhibitor of acetylcholine at the muscarinic receptor (reverses muscarinic symptoms), followed by pralidoxime, a cholinesterase-reactivating agent that treats both nicotinic and muscarinic symptoms.
38
What is spasticity?
Spasticity can be caused by the loss of descending inhibitory signals from upper motor neurons, leading to a hyperactive stretch reflex that results in increased muscle tone.
Disruption of the afferent (sensory) arm of the stretch reflex through a selective dorsal rhizotomy can improve spasticity without causing paralysis.
39
What is liquefactive necrosis?
characterized by complete digestion and removal of necrotic tissue with formation of a cystic cavity.
Irreversible ischemic CNS injury is typically followed by liquefactive necrosis due to the release of lysosomal enzymes from inflammatory cells and damaged neurons.
40
What is tubal factor infertility?
Tubal factor infertility, which occurs due to tubal scarring and obstruction, is a complication of pelvic inflammatory disease.
The risk for permanent tubal scarring increases with inadequate antibiotic treatment due to persisting or prolonged infection of the upper genital tract.
41
Adverse effect of cyclosporine
Calcineurin inhibitor nephrotoxicity with resultant impariement of renal function is the most significant adverse effect of cyclosporine.
Cytochrome P450 (CYP3A) is responsible for cyclosporine metabolism in the small intestine and liver. Grapefruit juice inhibits this enzyme and increases the nephrotoxicity of cyclosporine by raising circulating drug levels (pharmacokinetic interaction)
42
What is an arteriovenous fistula?
An arteriovenous fistula allows blood to shunt from the arterial circulation to the venous circulation, bypassing the high resistance of the systemic arterioles.
This leads to reduced systemic vascular resistance (ie, reduced afterload), increased venous return (ie, increased preload), and increased stroke volume. Left ventricular contractility is unchanged.
43
What is transient global amnesia?
a self-limited syndrome characterized by the sudden onset the prominent anterograde amnesia accompanied by repetitive questioning.
Symptoms correlate with transient dysfunction of the hippocampus, the brain area responsible for the formation of new memories.
44
What is Lyme carditis?
Early disseminated Lyme disease can have cardiac involvment (Lyme carditis) that most commonly manifests with varying degrees of atrioventricular (AV) conduction block.
Patients may be asymptomatic, but those with complete AV conduction block are likely to have dyspnea, lightheadedness, or syncope.
45
What is the pathogenesis of listeria monocytogenes?
Listeria monocytogenes is a facultative intracellular, gram+ rod that most often causes febrile gastroenteritis.
Pathogenesis is mediated largely by listeriolysin O, an enzyme that creates pores in phagosomes, which allows the bacteria to escape lysosomal destruction.
Pregnant women in the third trimester are at greatest risk; infection increases the risk of fetal demise, early labor, and neonatal infection.
46
What is cutaneous squamous cell carcinoma?
classically presents as a rough or scaly (keratinized) nodule.
Diagnosis is made with biopsy, which typically reveals nests of dysplastic keratinocytes with eosinophilic cytoplasm (due to keratin filaments). Dermal involvement signifies invasive SCC.
47
What is mercury toxicity?
Mercury impairs the breakdown of catecholamines, and toxicity can lead to excessive stimulation of the sympathetic nervous system (eg, tachycardia, hypertension, diaphoresis).
A desquamating hypersensitivity rash can also occur, and deposition in the CNS can result in personality changes, insomnia, and tremor.
48
Coronary dominance is determined by?
the coronary artery supplying the posterior descending artery.
The posterior descending artery originates from the right coronary artery in the approximately 70-80% of patients (right dominant), both the right coronary and left circumflex artery in 10-20% (codominant), and the left circumflex artery in 5-10% (left dominant).
The dominant coronary artery supplies blood to the atrioventricular (AV) node via the AV nodal artery.
49
What is the pathogenesis of alcohol-induced hepatic steatosis?
involves excess NADH production (via ethanol metabolism), which inhibits free fatty acid oxidation and promotes lipogenesis. Steatosis is microscopically characterized by clear cytoplasmic vacuoles within hepatoctyes.
50
Difference between short acting beta-2 agonists and long-acting beta-2 agonists?
Short-acting beta-2 agonists (eg, albuterol, levalbuterol) are hydrophilic and are rapidly metabolized, explaining their rapid onset and short duration of action.
Long acting beta-2 agonists (eg, salmeterol, formoterol) have a prolonged duration of action due to their lipophilic side chain, which allows them to attach to the cell plasma membrane. Salmeterol also binds to a secondary exosite within the beta-2 receptor, anchoring the molecule and further prolonging its action.
51
What is mycobacterium tuberculosis infection is controlled by?
controlled by coordination between macrophages and T lymphocytes. Conditions that impair immune function increase the risk of active tuberculosis; this includes chronic kidney disease, diabetes mellitus, HIV, substance abuse, malnutrition, and advanced age.
52
What are the renal effects of preeclampsia?
Preeclampsia is new onset hypertension after 20 weeks gestation with signs of end-organ damage (eg, headache).
Renal effects of preeclampsia include oliguria with increased specific gravity, proteinuria, and serum creatinine levels.
53
What is lecithinase (alpha toxin)?
the main toxin produced by Clostridium perfringens. It degrades lecithin, a component of cellular phospholipid membranes, which leads to membrane destruction, cell death, and widespread necrosis and hemolysis.
54
What are the morphologic findings in hypertensive (malignant) nephrosclerosis?
Hyperplastic arteriosclerosis (onion skinning) and fibrinoid necrosis of the renal arterioles are typical.
End organ damage can be prevented by treatment of high blood pressure with antihypertensives.
55
What can trigger the classical complement cascade?
The binding of autoantibodies to host antigens can trigger the classical complement cascade, leading to low C4 and C3 levels. Because autoantibodies do not activate the alternative complement cascade, factor B levels remain normal. This pattern is frequently seen in rheumatologic disease such as systemic lupus erythematosus.
56
What is nodular glomerulosclerosis?
characterized by increased mesangial matrix deposition, forming Kimmelstiel-Wilson nodules. It is most commonly caused by diabetic nephropathy and indicates irreversible glomerular damage with a rapid decline in kidney function.
57
What is the most common type of bladder cancer?
Urothelial (transitional cell) carcinoma.
Tumor stage is the most important factor for determining prognosis and is based on the depth of invasion into the bladder wall and the degree of regional (eg, lymph nodes) and metastatic spread. Tumor invasion into the muscularis propria layer of the bladder wall carries an unfavorable prognosis.
58
What is the TATA box?
a promoter region that binds transcription factors and RNA polymerase II during the initiation of transcription.
It is located approximately 25 bases upstream from the beginning of the coding region.
59
CD14 is a marker for?
The caseating granulomas of tuberculosis are surrounded by large epitheliod macrophages with pale pink granular cytoplasm.
CD14 is a surface marker most specific to the monocyte-macrophage cell lineage.
60
Where is the atrioventricular node located?
located on the endocardial surface of the right atrium, near the insertion of the septal leaflet of the tricuspid valve and the orifice of the coronary sinus
61
What is transference?
the unconscious recreation of patterns from past relationships in the present treatment relationship with related emotions, thoughts, and behaviors.
It can be negative or positive and influences physician-patient interactions.
Transference is the unconscious shifting of emotions associated with a significant person from one's past to a person in the present.
62
What is mitral stenosis?
usually occurs due to underlying rheumatic heart disease and initially presents with exertional dyspnea.
Orthopnea, paroxysmal nocturnal dyspnea, productive cough, and hempotysis can develop as the disease becomes more advanced.
At rest, left ventricular diastolic pressure, afterload, and contractility remain normal until the mitral stenosis is severe.
63
How is strep agalactiae (group B strep) identified?
Strep agalactiase (group B strep), one of the most common causes of early neonatal sepsis, is typically identified by the presence of a narrow zone of beta-hemolysis when plated on blood agar.
It is also identified by the production of CAMP factor, which enhances beta-hemolysis by particular strains of staph aureus
64
In patients with mitral regurgitation, left ventricular afterload is determined by?
the balance of resistance between forward flow (aortic pressure) and regurgitant flow (left atrial pressure).
A reduction in systemic vascular resistance increases the ratio of forward to regurgitant blood flow and improves cardiac output.
65
Diabetic peripheral neuropathy results from?
Diabetic peripheral neuropathy is characterized by numbness and paresthesia in a stocking and glove distribution. It results from nonenzymatic glycosylation of proteins, leading to hyalinization of endoneurial arteries and ischemic nerve damage.
In addition, accumulation of toxic substances within neurons results in deranged metabolism and increased oxidative stress.
66
MOA of imiquimod
a widely used topical immunomodulatory agent that stimulates a potent cellular and cytokine based immune response to aberrant cells (eg, human papillomavirus-infected cells in anogenital warts) by activating toll like receptors and upregulating NF-kB.
Other antiproliferative effects of imiquimod include inhibition of angiogenesis and induction of apoptosis.
67
In patients with Tetralogy of Fallot, squatting during a Tet spell does what?
increases systemic vascular resistance and decreases right to left shunting, thereby increasing pulmonary blood flow and improving oxygenation status.
68
Histopath for Crohn disease
Noncaseating granulomas are a hallmark of Crohn disease and can help distinguish it from ulcerative colitis, which does not form granulomas.
Histopath in Crohn disease also demonstrates transmural inflammation, distortion of the normal architecture, and Paneth cell metaplasia.
69
What is malabsorption?
a syndrome of impaired intestinal digestion and absorption. Fats are typically the most severely affected macronutrient in generalized malabsorption, and testing the stool for fat (eg, with Sudan III stain) is the most sensitive strategy for screening for malabsorptive disorders.
70
What is Von Hippel-Lindau disease?
an autosomal dominant condition caused by a mutation in a tumor suppressor gene, which is associated with the development of pheochromocytomas, retinal and cerebellar hemangioblastomas, and renal cell carcinomas.
Because of the potential for serious complications from these tumors, patients with VHL should receive annual surveillance, including plasma metanephrines, abdominal imaging, ophthalmologic examination, and MRI of the brain and spine.
71
What is seen on CT for a subarachnoid hemorrhage?
Sudden onset, severe headache with signs of meningeal irritation (eg, neck pain, stiffness) should raise suspicion for subarachnoid hemorrhage.
SAH usually results from rupture of a saccular berry aneurysms, and it is recognized on CT scan by blood pooling in the cerebral sulci and basal cisterns.
72
Prolactin secretion is stimulated by?
Prolactin production is regulated primarily by inhibitory effects of hypothalamic dopaminergic pathways.
However, prolactin secretion is stimulated by thyrotropin-releasing hormone.
In patients with primary hypothyroidism, the increased production of TRH by the hypothalamus can lead to hyperprolactinemia.
73
Beta-2 agonists (albuterol, dobutamine) can cause transient hypokalemia due to?
Potassium is primarily stored intracellularly (~98% of total body stores) through the action of Na-K-ATPase pump. Beta-adrenergic activity increases the activity of Na-K-ATPase pump, therefore both endogenous catecholamines and therapeutic beta 2 agonists can cause transient hypokalemia due to increased transport of potassium intracellularly.
74
MOA of warfarin
blocks epoxide reductase, which lowers the reduced form of vitamin K in the liver; this prevents gamma carboxylation of vitamin K dependent clotting factors (II, VII, IX, and X). Because warfarin only blocks the generation of new clotting factors, therapeutic effect is delated 3-5 days until preexisting clotting factors are consumed.
75
What occurs in the development of atherosclerotic plaque (atheroma)?
During the development of atherosclerotic plaque (atheroma), activated macrophages, platelets, and endothelial cells release growth factors (eg, platelet-derived growth factor) that stimulate recruitment of smooth muscle cells from the arterial wall media and their subsequent proliferation in the intima.
76
What is cryptococcus neoformans?
causes meningoencephalitis in patients with untreated AIDS.
Diagnosis can be made by detecting the polysaccharide capsule in cerebrospinal fluid using the latex agglutination test.
India ink staining of cerebrospinal fluid is also used for diagnosis and can demonstrate round or oval budding yeast.
77
What is foscarnet?
an analog of pyrophosphate that can chelate calcium and promote nephrotoxic renal magnesium wasting.
These toxicities can result in hypocalcemia and hypomagnesemia, which can cause seizures.
78
What is seen in ST-elevation myocardial infarction?
involves transmural (full thickness) infarction of the myocardial wall, and usually results from acute atherosclerotic plaque rupture with the development of overlying thrombus that fully occludes the coronary artery lumen.
It classically presents with sudden-onset substernal chest pain that is not relieved by rest or short-acting nitrates.
ECG: ST elevation in the affected leads with subsequent development of Q waves.
79
Chronic kidney disease can cause hyperphosphatemia due to?
decreased renal excretion of phosphorus.
Dietary phosphorus restriction is recommended, but oral phosphate binders are often needed.
Sevelamer is a nonabsorbable anion-exchange resin that binds intestinal phosphate to reduce absorption
80
Thioamines (eg, methimazole, propylthiouracil) decrease the formation of thyroid hormones via?
inhibition of thyroid peroxidase, the enzyme responsible for both iodine organification and coupling of iodotyrosines.
Propythiouracil also decreases the peripheral conversion of T4 to T3.
81
What is scarlet fever?
fever, pharyngitis, sandpaper like rash, circumoral pallor, and strawberry tongue.
It is caused by strains of Group A strep that produce pyrogenic exotoxins. Scarlet fever can predispose to acute rheumatic fever and glomerulonephritis.
82
What is bullous impetigo?
a superficial infection by Staph aureus that is most common in young children.
It is characterized by a blistering skin rash with tan to honey colored crusts. The blistering in bullous impetigo is caused by exfoliative toxin A, which targets desmoglein 1 in epidermal cellular junctions and causes a loss of cell adhesion.
83
What is silicosis?
characterized by dyspnea and productive cough occuring years after inhalational exposure to crystalline silica.
Histo: birefringent silicate particles within dense, whorled collagenous nodules surrounded by dust-laden macrophages.
Radiography: numerous small, rounded nodules predominant in the upper lobes; calcification of the rum of hilar nodes (eggshell calcification) may also be seen.
84
What is at risk of injury during thyroidectomy?
The external branch of the superior laryngeal nerve is at risk of injury during thyroidectomy due to its proximity to the superior thyroid artery and vein.
This nerve innervates the cricothyroid muscle.
85
What is septic shock?
Septic shock can present with either hyper or hypothermia. The initial disturbance is peripheral vasodilation leading to decreased systemic vascular resistance, decreased central venous pressure, and decreased pulmonary capillary wedge pressure.
A compensatory increase in sympathetic drive causes an increase in cardiac output; the resulting high flow rates lead to incomplete oxygen extraction in the tissues, resulting in high mixed venous oxygen saturation.
86
What is seen in emphysema?
Emphysema involves inflammatory and proteolytic destruction of the alveolar septa.
In severe disease, dilated alveolar pockets progressively merge into subpleural blebs. These are prone to rupture, leading to pneumothorax.
87
Why does angina occur in aortic stenosis?
Angina often occurs in aortic stenosis even in the absence of obstructive coronary artery disease. It results from increased myocardial oxygen demand due to an increase in left ventricular mass (ie, concentric hypertrophy) and ventricular wall stress.
88
What is uterine sarcoma?
a rare but aggressive malignant tumor of the uterine myometrium and/or endometrial stromal tissue.
Patients typically have clinical features similar to those with uterine leiomyomas (eg, abnormal uterine bleeding, immobile pelvic mass), but uterine sarcoma can be distinguished by microscopy, which typically shows malignant features such as nuclear atypia, abundant mitoses, and tumor necrosis.
89
What are the labs in folate deficiency?
Reduced forms of folate serve as methyl group donors in the synthesis of methionine.
Folate def leads to impaired methionine synthesis with accumulation of homocysteine, a precursor to methionine.
Methylmalonic acid metabolism is unaffected by folate deficiency.
90
Ventromedial nucleus mediates what?
mediates satiety; lesions of this area of the hypothalamus can result in hyperphagia and obesity.
91
What is functional hypothalamic amenorrhea?
results from loss of pulsatile gonadotropin-releasing hormone release from the hypothalamus and is caused by weight loss, strenuous exercise, systemic illness, or abnormal eating habits.
Loss of cyclic gonadotropin release leads to a decrease in LH and FSH secretion from the pituitary, which in turn causes low circulating estrogen levels.
92
What is hypertrophic cardiomyopathy?
an autosomal dominant genetic disorder caused by mutation in one of several genes encoding the myocardial contractile proteins of the cardiac sarcomere.
Mutations that affect cardiac myosin binding protein C or cardiac beta-myosin heavy chain are responsible for the majority of identifiable mutations in patients with HCM.
93
Patients with cystic fibrosis are at risk for fat-soluble vitamin (DEAK) deficiency due to?
fat malabsorption from pancreatic insufficiency.
Vitamin K is an important cofactor in the activation of coagulation factors II, VII, IX, and X.
Vitamin K deficiency leads to easy bruising, mucosal bleeding, and prolonged PT.
94
Untreated phenylketonuria leads to?
irreverisble neurologic abnormalities (eg, intellectual disability, seizures), as well as reduced melanin production and a musty odor.
Pathophysiology involves impaired metabolism of phenylalanine to tyrosine, and treatment includes a phenylalanine-restricted diet that may require supplemental tyrosine.
95
A large, acute pulmonary embolism causes what to the right side of the heart?
causes a rapid increase in right ventricular pressure that leads to RV cavity enlargement and RV dysfunction.
Thickening of the RV wall is not seen in acute pulmonary embolism, as there is no time for compensatory hypertrophy to occur in response to the increased pressure load.
96
What is atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP)?
are secreted by atrial and ventricular cardiomyocytes in response to myocardial stretching induced by hypervolemia.
These natriuretic peptides inhibit the renin-angiotensin-aldosterone system and stimulate peripheral vasodilation and increased urinary excretion of sodium and water.
Neprilysin inhibitors (eg, sacubitril) prevent the degradation of ANP and BNP, enhancing their beneficial effects in heart failure.
97
Stress urinary incontinence is common in pregnancy due to?
Stress urinary incontinence, the leakage of urine with increased intraabdominal pressure (eg, coughing), is common in pregnancy due to decreased external urethral sphincter tone and increased pelvic floor muscle laxity.
98
What is cyanotic congenital heart disease?
characterized by hypoxemia that does not improve with oxygen administration.
In transposition of the great arteries, deoxygenated blood from the right ventricle is delivered to the systemic circulation while oxygenated blood cycles through the pulmonary circulation (ie, parallel circuits)
99
Vitamin B12 (cobalamin) deficiency can cause subacute combined degeneration due to?
impaired myelination in the ascending dorsal columns and spinocerebellar tracts (diminished position/vibration sense, ataxia), as well as the descending lateral corticospinal tracts (eg, muscle weakness, spastic paresis)
100
What is chiari malformations?
congenital disorders that result from underdevelopment of the posterior fossa, causing parts of the cerebellum and medulla to herniate through the foramen magnum.
Chiari type I is relatively benign and presents during adulthood with occipital headache and cerebellar dysfunction.
Chiari type II is a more severe form that affects neonates and is often associated with lumbar myelomeningocele and hydrocephalus.
