Uworld 6 Flashcards
cumulative incidence calculation
total number of new cases of a disease over a specific period divided by the number of people at risk at the beginning of the period
histologic findings of basal zone hyperplasia, elongation of the lamina propria papillae, and scattered eosinophils and neutrophils
GERD
gastroesophageal junction incompetence is primary mechanism
How does ionizing radiation do its thing?
What tissue does it most affect?
DNA double strand breakage or free radical formation
affects rapidly dividing tissues because they cannot repair fast enough - so the malignancy, but also epithelial surfaces
Lithium taken during pregnancy is associated with…
Ebstein’s anomaly
characterized by apical displacement of the tricuspid valve leaflets, decreased RV volume, and atrialization of the RV
What is the non-glucose monosaccarhide that is able to bypass phosphofructokinase?
because of this, what happens?
fructose
metabolized by the liver faster than the other monosaccharides and is rapidly cleared from the bloodstream following dietary absorption
activation of the carotid sinus baroreceptor sends afferents through what pathway?
efferents then come via…
afferent limb goes to medullary centers via the Hering nerve, a branch of the Glossopharyngeal nerve
the efferent limb of the carotid sinus carries parasympathetic impulses via the vagus nerve
You are suspiscious of CF in a pt, but the Cl- sweat test came back normal. What is another useful diagnostic adjunct?
measure the nasal transepithelial protential difference
- saline solution applied to nose
- CF pts will have increased Na absorption
- CFTR channel secretes Cl- into lumen and has a tonic inhibitory effect on the opening of the epithelial Na channel (ENaC) which decreases Na reabsorption into the cell
- high luminal salt content helps retain water in the lumen, forming well-hydrated mucus
- so Na is absorbed intracellularly but Cl- in the saline solution is retained in the lumen
- the higher relative amounts of negatively charged Cl- on the epithelial surface results in a more negative transepithelial voltage difference
cyclic breathing in which apnea is followed by gradually increasing then decreasing tidal volumes until the next apneic period
what is this called?
When is it seen?
Cheyne-Stokes breathing
often seen in advanced CHF
Rb protein regulates what part of the cell cycle?
G1 to S
Mycoplasma pneumoniae attaches to the respiratory epithelium using…
they are also present where?
surface antigens - I-antigen
also present on the plasma membrane of erythrocytes
hydralazine and minoxidil are…
selective arteriolar vasodilators to lower BP by reducing systemic vascular resistance
taking too many NSAIDs in a kid - what kidney injury?
minimal change disease
What is the earliest sign of diabetic nephropathy?
moderately increased albuminuria
screening is best achieved using an albumin-specific urine assay (regular dipstick UA has low sensitivity)
Milrinone MOA
PDE-3 enzyme inhibitor that can be used in pts with refractory heart failure due to LV systolic dysfunction
positive inotrope and vasodilator
the fact that a researcher’s beliefs in the efficacy of treatment can potentially affect the outcome is known as
Pygmalion effect
the paracortex of the lymph node is populated by…
when would this area become enlarged?
T lymphocytes and dendritic cells
becomes enlarged by the proliferation of T lymphocytes during adaptive cellular immune responses (eg viral infections)
Where in the lymph nodes are B cells localized and proliferate?
follicles in the outer cortex
primary follicles are dense and dormant; secondary follicles have a pale germinal center containing proliferating B cells and follicular dendritic cells
What does the medulla of the lymph node hold?
consists of medullary cords and sinuses
medullary cords contain B cells, plasma cells, and macrophages;
medullary sinuses contain reticular cells and macrophages
intracellular protozoa with rod-shaped kinetoplasts
dx?
how does this spread?
cutaneous leishmaniasis
bites from infected sand flies
How long do depression symptoms have to be going on to count as MDD?
greater than or equal to 2 weeks
What are the time frames and ddx leading up to schizophrenia?
- brief psychotic disorder (1 day to 1 month)
- sudden onset, full return to function
- schizophreniform disorder (1 month to 6 months)
- same ssx as schizophrenia, functional decline not required
- schizophrenia (greater than 6 mo)
- includes at least 1 mo of active ssx, can include prodromal and residual periods
- requires functional decline
pts with prolactinoma and high levels of circulating prolactin, what will happen hormonally?
suppress GnRH secretion from HT, leading to reduced secretion of LH and subsequent hypogonadism, anovulation, and amenorrhea
estrogen deficiency
If a mutation affects an exon, the mutation will be detectable in the….
deletion or addition of a number of bases that is not divisible by 3 in the coding region of a gene will cause…
mRNA sequence
frameshift mutation
excessive raw egg white consumption can lead to
biotin deficiency
due to high levels of biotin-binding avidin in egg whites
biotin/B7 is an important cofactor for what kind of enzymes? what does it do?
carboxylase enzymes
functions as a CO2 carrier and plays an essential role in carbohydrate, lipid, and amino acid metabolism;
in liver, the conversion of pyruvate to oxaloacetate for gluconeogenesis requires pyruvate carboxylase and biotin
extensive hepatocellular damage causing the liver to rapidly atrophy and appear shrunken on autopsy; s/p surgery (any surgery)
what is this likely due to?
fulminant hepatitis likely due to halogenated anesthetics (halothane in particular)
What will be lab findings from inhaled-anesthetic hepatotoxicity?
markedly elevated serum aminotransferase levels
prolonged PT (due to fialed hepatic synthetic function and deficiency of factor VII- shortest half life)
leukocytosis
eosinophilia
What are two important congenital syndromes that can cause QT prolongation?
- Jervell and Lange-Neilsen syndrome
- AR with neurosensory deafness
- Romano-Ward Syndrome (more common)
- AD no deafness
both can predispose to Torsades at a young age, causing syncopal episodes and SCD
AT II will stimulate the release of what two things, leading to what?
aldosterone and endothelin 1
increase Na+ and water reabsorption and systemic vascular resistance to help maintain BP
What is the most common mechanism of aminoglycoside (genatmicin) resistance?
antibiotic-modifying enzymes adding chemical groups (acetyl, adenyl, and phosphate)
Chronic use of opioids generally cause development of tolerance to analgesic effects and most AEs, except for
constipation and miosis
What are the MCC of acute pancreatitis?
gallstones and alcoholism
First symptom of this disease is usually severe pruritis (especially at night)
primary biliary cirrhosis
AI destruction of the intrahepatic bile ducts and cholestasis (elevated alkaline phosphatase)
fatty streaks are composed of what?
collection of lipid laden macrophages (foam cells) in the intima that can eventually progress to atherosclerotic plaques
AE of spironolactone (not the K+ sparing part)
antiandrogenic effects, can cause gynecomastia, decreased libido, and impotence
What are the two main virulence factors of Bacillus anthracis?
- polypeptide capsule
- composed of poly-gamma-D-gltuamic acid
- inhibits phagocytosis
- trimeric exotoxin
- composed of protective ag, edema factor, lethal factor
calmodulin-dependent adenylate cyclase that increases cyclic AMP concentration, leading to accumulation of fluid within/between cells and suppression of neutrophil and macrophage function
edema toxin in bacillus anthracis
Bacillus anthracis edema factor functions similarly to what other toxin/pathogen?
similar to adenylate cyclase toxin, produced by Bordetella pertussis
end-organ hypoperfusion in septic shock impairs tissue oxygenation and decreases oxidative phosphorylation, leading to a buildup of NADH and….
shunting pyruvate to lactate following glycolysis
lactic acidosis
What are the physiologic end effects of lactose intolerance?
- increased breath hydrogen content
- decreased stool pH
both from the fermentation of undigested lactose by gut bacteria leading to increased production of short chain FA that acidify the stool and create excess H+ to be exhaled
- elevated stool osmolality
- from high amounts of undigested lactose, which attracts excess water in the bowel lumen
ptosis, downward and laterally deviated eye, impaired pupillary constriction and accomodation, and diagonal diplopia
dx?
why does this eye position occur?
oculomotor nerve palsy
unopposed action of the superior oblique (CN IV) and lateral rectus (CN VI) muscles
more than 2 layers of proliferating cells within the Bowman space would be considered…
these form in response to…
glomerular crescents
immune or inflammatory-mediated injury to golmerular capillaries
What do crescents in rapidly progressive gomerularnephritis consist of?
consist of golmerular parietal cells, lymphocytes, and macrophages, along with abundant fibrin deposits
crescents eventually become fibrotic, disrupting glomerular function and causing renal injury
low systemic vascular resistance and decreased preload is consistent with what kind of shock?
what is the MCC?
distributive shock
MCC due to bacterial infection
under hypoxic conditions, intracellular accumulation of NADH inhibits ….
as a result…
pyruvate dehydrogenase
increased amounts of pyruvate are converted to lactate by lactate dehydrogenase, which regenerates NAD+ from NADH
pyruvate is converted to oxaloacetate by
pyruvate carboxylase
2-phosphoglycerate is converted to phosphoenolpyruvate by…
then PEP is metabolized by … to pyruvate
enolase
pyruvate kinase
MOA of spironolactone and eplerenone?
aldosterone receptor antagonists, inhibit the effects of aldosterone and reduce secretion of K+ and H+ by the collecting tubule
What is the mechanism of glucose being transported into cells?
What is unique about them?
facilitated diffusion
move high concentration to low concentration with the help of transmembrane glucose transporter proteins (GLUT)
carrier proteins are stereoselective and have preference for D-glucose
Where does lymph drainage go from the testes, glans penis, scrotum, and cutaneous posterior calf?
testes - directly to para-aortic (retroperitoneal) LN
glans penis and cutaneous portion of posterior calf - deep inguinal LN
scrotum - superficial inguinal nodes
What drugs increase the frequency of chloride channels opening?
What drugs increase the duration of chloride channels opening?
increased frequency - benzodiazepines
increased duration - barbituates
What are the MCC of metabolic alkalosis?
How does each of these causes occur?
- vomiting or nasogastric suctioning
- loss of H+ and Cl- ions in gastric secretions causes a net gain of alkali
- loss of Cl- also impaire HCO3- excretion
- present with hypotension and low urine Cl-
- saline responsive
- thiazide or loop diuretic use
- block absorption of Na+ and Cl- ions at the DCT and LOH, respectively
- distal delivery NaCl increases while the volume depletion stimulates aldosterone
- increase Na+ reabsorption at the expense of K+ and H+ urinary loss
- present with high urine Cl- when diuretic use is ongoing, and low urine Cl- after it is stopped
- saline responsive
- mineralocorticoid excess state
- hyperaldosteronism (Conn Syndrome) or primary hypercortisolism (Cushing Syndrome)
- increases Na+ reabsorption and urinary K+ and H+ losses, leading to a relative increase in serum HCO3-
- present with HTN and high urine Cl- due to expanded ECF vol causing pressure natriuresis
- saline unresponsive
blowing, holosystolic murmur heard best over teh cardiac apex with radiation to the axilla
mitral regurg
engorged alveolar capillaries with pink, acellular material within the alveoli is characteristic of…
this is consistent with…
increased pulmonary venous pressure amd transudation of fluid plasma across the alveolar-capillary membrane
acute pulmonary edema caused by increased alveolar capillary hydrostatic pressure from L-sided heart failure
What is happening in third degree AV block?
conduction between the SA node and AV node is impaired, so AV node has taken over, complete dissociation between the atria and ventricle contraction
CFTR gene mutation with deltaF508 causes what?
deletion causes abnormal protein folding and failure of glycosylation
acute morbidity of acute rheumatic fever is likely due to
pancarditis
DNA binding proteins include what?
- transcription factors
- myc, CREB
- steroid receptors
- cortisol, aldosterone, progesterone
- thyroid hormone receptor
- fat soluble vitamin receptors
- vit D, retinoic acid
- DNA transcription and replication proteins
How does the Hep B vaccine work?
- recombinant HBsAg to generate protective immunity against the virus
- HBsAg is collection of envelope glycoproteins found on the surface of HBV
- they mediate attachment of virus to hepatocytes and subsequent viral entry
- pts who adequately respond generate anti-HBs antibodies
- bind to circulating viral particles and prevent attachment to and penetration of hepatocytes
How can noninfectious viruses become infectious?
tissue tropism of viruses is primarily mediated by viral surface glycoproteins that bind to specific host cell receptors
mutations to viral surface glycoproteins can alter tissue tropism
What is hemagglutinin?
viral surface glycoprotein, binds the sialic acid receptor on human respiratory epithelial cells
antigenic changes to this can alter the tissue tropism of the virus and allow it to infect more species/humans
histology and symptoms of Neimann-Pick disease
- cells that appear enlarged, foamy, and vacuolated on EM
- lipid laden foam cells accumulate in liver and spleen and CNS
- hepatosplenomegaly, hypotonia, and neurodegeneration
- period of normal development, then infants fail to attain new skills and lose previously acquired milestones
- retinal accumulation leads to cherry-red macular spot
- death by 3 yo
What elements are required for PCR?
- source DNA template that includes target region to be amplified along with flanking sequences adjacent to the target region
- oligonucleotide sequence of these flanking regions must be known in order to make the primers necessary to start PCR
- thermostable DNA polymerase used to replicate the DNA template from a pool of supplied deoxynucleotide triphosphates using 3 steps:
- denaturing
- annealing
- elongation
Most of the K+ filtered by the glomeruli is reabsorbed in the…
the late distal and cortical collecting tubules are the primary sites for ….
K+ depletion stimulates…. to reabsorb extra K+
….. secrete K+ under conditions of normal or increased K+ load
PCT and LOH
regulation of K+ in the urine
alpha-intercalated cells
principal cells
drug associated with violent behavior, dissociation, hallucinations, amnesia, nystagmus, and ataxia
PCP - phencyclidine
PCP MOA
NMDA gluatamate receptor antagonist and monoamine reuptake inhibitor
markedly elevated blood pressure, HA/vomiting suggesting increased ICP, in conjunction with bilateral abdominal bruits would suggest…
renovascular hypertension from bilateral renal artery stenosis (RAS)
What hormones change in response to increased renal artery stenosis and what happens to K+?
decreased renal artery perfusion activates RAS
- increase renin
- increase AT II
- increase aldosterone
- increases renal Na+ reabsorption and K+ and H+ excretion
- hypokalemia and metabolic alkalosis
Tx for neuroleptic malignant syndrome and MOA
discontinue cuasative agent and supportive care
dantrolene can be used - antagonizes ryanodine receptors and inhibits calcium release from the SR
bromocriptine, a dopamine agonist has also shown clinical benefit
What is the MC CNS tumor in I/C pts?
how does it appear microscopically?
primary CNS lymphoma
dense, cellular aggregates of uniform, atypical lymphoid cells
most arise from B-cells
DLBCL is MC subtype
commonly positive for CD20 and CD79a
universally associated with EBV
Asian kid with fever for past 5 days; more irritable than usual and had 2 or 3 episodes of vomiting
PE: bilateral conjunctival injection with no exudates, tongue bright red and cracked lips, nonpitting edema on hands and feet
dx?
at risk for developing?
Kawasaki disease
risk cornary artery aneurysm
during wound healing, excessive matrix metalloproteinase activity and myelofibroblast accumulation int he wound margins can result in…
contractures
contractures produce deformities of the wound and surrounding tissues, most often on palms, soles, anterior thorax, or at serious burn sites
a poorly soluble gas will have what kind of blood/gas coeffecient?
poorly soluble gas has decreased blood/gas coefficient
blood saturates quickly, leading to a fast rise in partial pressure
increased pressure speeds brain saturation, decreasing onset time
….. soluble anesthetics dissolve easily in the blood, and thus …. amounts must be absorbed before the blood becomes saturated
highly
larger
blood solubility of an anesthetic is indicated by its…
blood/gas coefficient
anesthetics with higher blood solubility have larger blood/gas coefficients
What is an example of a poorly soluble gas and a highly soluble gas?
- poorly soluble gas - Nitrous oxide
- small amount needed to saturate the blood
- rapid rise in partial pressure in the blood
- rapid equilibration with the brain
- rapid onset of action
- highly soluble gas - halothane
- large amount needed to saturate the blood
- slow rise in partial pressure in blood
- slow equilibration with the brain
- slow onset of action
colonoscopy showing flask shaped ulcers
entamoeba histolytica
younger pt with abdominal pain, heme-positive stool, and noncaseating granulomas on microscopy
dx?
how do you describe these noncaseating granulomas?
Crohn disease
accumulation of epithelioid macrophages that frequently form multinucleated giant cells without central necrosis, surrounded by a cuff of lymphocytes
What does the obturator nerve innervate?
obturator externus, then divides into anterior and posterior branches that supply the rest of the thigh adductor muscles (adductor longus, brevis, magnus)
anterior division of the nerve gives off a terminal cutaneous branch that provides sensation over the distal medial thigh
contact dermatitis, granulomatous inflammation, and reactive skin testing are all what types of hypersensitivity reactions?
type IV HS rxn (T cell mediated) delayed type hypersensitivity
ANP and BNP are broken down and inactivated by the …
metalloprotease neprilysin
A neprilysin inhibitor like sacubitril will…
enhance activity of ANP and BNP
adrenal crisis is characterized by…
severe hypotension, abdominal pain, vomiting, weakness, and fever
AR disorder with bilateral sensorineural hearing loss and congenital long QT syndrome, predisposing to sudden cardiac death
dx?
why does this happen?
Jervell and Lange-Nielsen syndrome
occurs secondary to mutations in genes (eg KCNQ1, KCNE1) that encode the alpha and beta subunits of voltage-gated potassium channels
AD condition that can be associated with mutations in cardiac sodium or L-type calcium channels, leading to characteristic EKG changes and an increased risk of ventricular tachyarrhythmias and SCD
dx?
what are the EKG changes?
Brugada syndrome
pseudo RBBB, ST segment elevation in V1-V3
what are treatments for hepatic encephalopathy?
lactulose (increase conversion of amonia to ammonium) and rifaximin (decreases intraluminal ammonia production)
What are common triggers for hepatic encephalopathy?
GI bleeding can precipitate HE as hemoglobin breakdown leads to increased nitrogen products in the gut
excess dietary protein intake
infection
sedatives
metabolic derangements (eg hypokalemia)
How do you dx cholecystitis?
dx made by identifying signs of GB inflammation on US
if inconclusive, nuclear medicine hepatobiliary scanning can be used to assess cystic duct patentcy
digital clubbing, a thickening of the distal phalanges associated with…
what pt dx would you see?
a number of chronic diseases causing hypoxia
large cell lung cancer, tuberculosis, cystic fibrosis, and suppurative lung diseases like empyema, bronchiectasis, and chronic lung abscesses
chest XR in acute decompensated heart failure shows
prominent pulmonary vessels, patchy bilateral airspace opacification, and blunting of the costophrenic angles due to pleural effusions
Why do pregnant women get GERD?
elevated levels of progesterone and estrogen cause relaxation of the smooth muscle of the lower esophageal sphincter
later in prego, it can be from the gravid uterus pressing up on the stomach leading to an altered LES angle or increased gastric pressure
alkaptonuria is a relatively benign childhood disorder marked by what in adult life?
what causes this disorder?
severe arthritis
AR disorder caused by deficiency of homogentisic acid dioxygenase, which normally metabolizes homogentisic acid into maleylacetoacetate
accumulated homogentisic acid like in alkaptonuria, causes
pigment deposits in CT throughout the body
during adulthood, these black-blue deposits become apparent in the sclerae and ear cartilage; deposits also occur in the large joints and spine, causing ankylosis, motion restriction, an significant pain
In response to LV pressure overload, there will be …. of genes encoding for contractile proteins of the cardiac sarcomere, including….
upregulation
beta-myosin heavy chain
What kind of mutation causes Hemoglobin C?
missense mutation that results in a glutamate residue being substituted by lysine in the beta globin chain
Why does isoniazid cause neuropathy?
is chemically similar to B6/pyridoxine; bc of the similarity, isoniazid can compete with vit B6 in the synthesis of mutliple neurotransmitters (including GABA), resulting in defective end products
What is the major trophic hormone of the zona fasciculata and reticularis? whereas the zona glomerulosa is regulated by…
ACTH
angiotensin II
What is your concern if you are intubating a pt with RA?
long-standing RA frequently involves the cervical spine and causes joint destruction with vertebral malalignment (subluxation); C1-C2 joint is most often involved
endotracheal intubation can acutely worsen the subluxation and cause compression of the spinal cord and/or vertebral arteries
What can happen with anterior dislocation of the head of the humerus?
- flattening of the deltoid
- protrusion of the acromion
- anterior axillary fullness
- axillary nerve is nerve MC injured
- innervates the deltoid and teres minor
- gives sensation to skin overlying lateral shoulder
How can tumor cells gain resistance to chemo?
MDR1 gene - prototype product of this gene is P-glycoprotein, a transmembrane protein that functions as an ATP-dependent efflux pump
has a broad specificity for hydrophobic compounds; can both reduce the influx of drugs into the cytosol and can icnrease efflux from the cytosol, thereby preventing the action of chemo agents
What are common triggers for erythema multiforme and why does it happen?
acute, inflammatory skin disorder usually develops during an ongoing infection; triggered by HSV or resp. inf like mycoplasma pna
caused by the deposition of infectious antigens in keratinocytes, leading to a strong cell-mediated (eg cytotoxic T cell) immune response
What is the first line treatment for essential tremor?
propanolol
non-specific beta-adrenergic antagonist
insurance plan with low monthly premiums, low copayments and deductibles, and low total cost for the pt;
reduce utilization by confining the pt to a limited panel of providers, requiring referrals from a PCP prior to seeing specialists, and denying payment for services that do not meet established EBM
HMO - health maintenance organization
What is a qualitative screening test that detects the presence of urinary cysteine?
sodium cyanide-nitroprusside test
fever, decreased urine output, and renal failure within the first several weeks of a renal transplant is suspiscious for…
which can be classified as…
How is this mediated?
acute rejection
cellular or antibody mediated rejection
mediated by host T lymphocytes sensitization against graft (foreign) MHC antigens, and is characterized by a dense infiltrate of mononuclear cells (eg lymphocytes) affecting the renal interstitium, tubules, and arterial intima
When does Graft v Host occur?
eg, s/p BMT, in which host lacks competent T lymphocytes
transplanted T lymphocytes attack host antigens that are recognized as foreign
How can you prevent acute rejection?
using calcineurin inhibitors such as cyclosporine or tacrolimus
What kind of cholesterol drug will cause hypertriglyceridemia?
bile acid-binding resins (cholestyramine, colestipol, colesevelam)
How does vitamin C play a role in collagen synthesis?
Within the RER, specific proline and lysine residues are post-translationally hydroxylated to hydroxyproline and hydroxylysine by prolyl hydroxylase and lysyl hydroxylase
vitamin C is a required cofactor for this post-translational modification
holosystolic murmurs are associated with…
tricuspid regurg, mitral regurg, and VSDs
a holosystolic murmur that increases in intensity on inspiration most likely represents…
tricuspid regurg
acne vulgaris is an inflammatory disorder of …
pilosebaceous follicles
New onset odynophagia in the setting of chronic GERD should raise suspiscion for..
erosive esophagitis with esophageal ulcers
What happens to the spleen with portal hypertension?
splenomegaly with congestive hypersplenism; venous congestion causes apparent expansion of teh red pulp of the spleen, which is composed of blood-filled sinuses and cords lined by reticuloendothelial-type cells
what hormones/drugs can reduce portal blood flow?
somatostatin and octreotide inhibit the release of endogenous hormones like glucagon and VIP that would induce splanchnic vasodilation, thereby indirectly reducing portal blood flow
What type of nephropathy is normally associtated with normal serum complement levels?
IgA nephropathy
recurrent hematuria that occurs spontaneously or within 5-7 days of an upper respiratory or pharyngeal infection (synpharyngitic hematuria)
IgA nephropathy
what type of cancer arises from parafollicular calcitonin-secreting C cells?
what does it look like on histology?
medullary thyroid cancer
nests or sheets of polygonal or spindle-shaped cells with extracellular amyloid deposits derived from calcitonin
How do you treat drug induced parkinsonism?
decrease or discontinue offending agent and treat with anticholinergic like benztropine
Where do loop diuretics work?
thick ascending limb of Henle’s loop
inhibit Na-K-2Cl symporter
brown v black pigment stones v sludge
gallbladder hypomotility results in excessive dehydration of bile; promotes biliary sludge - precursor to stones
brown stones are a/w biliary tract infections (microbes producing beta-glucruonidases)
black stones occur with chronic hemolytic anemias (SCD) and increased enterohepatic cycling of bilirubin
needle shaped intravascular cholesterol clefts, a characteristic finding in atheroembolic disease is likely to develop
acute kidney injury due to partial or complete occlusion of the arcuate or interlobular arteries
other organ systems commonly involved include skin, GI, and CNS
What do thiazide diuretics do to different substances?
- raise levels of
- calcium
- uric acid
- glucose
- cholesterol
- triglyceride levels
- lower serum levels of
- sodium
- potassium
- magnesium
What disease state comes with hypertriglyceridemia and what is the best method of treatment for this?
severe hypertriglyceridemia, pancreatic lipases can cause toxic levels of FFAs to be released within the pancreatic tissue, leading to acute pancreatitis
fibrates (eg fenofibrate) are the most effective tx
What part of the nephron is impermeable to water?
the ascending limb of the loop of Henle is impermeable to water regardless of serum vasopressin levels
absence of CD18 antigens
dx?
why is CD18 necessary?
Leukocyte adhesion deficiency (LAD)
necessary for the formation of integrins, which are essential for leukocyte adhesion to endothelial surfaces and migration to peripheral tissues in response to infection or inflammation
LAD related infections are notable for…
- lack of purulence due to absence of leukocytes in peripheral tissues
- impaired wound healing, including late separation (>21 days) of the umbilical cord
- persistent leukocytosis is common finding due to leukocytes not being able to migrate out of blood vessels
If 3 leads are used in a biventricular pacemaker, where are the leads placed within the heart?
- first 2 are placed in the RA and RV
- easy to place, need to traverse the L subclavian vein and SVC
- third lead is used to pace the LV
- more difficult to position, passes the L ventricular pacing lead from the RA into the coronary sinus, which resides in the atrioventricular goove on the posterior aspect of the heart
intraoperative finding of a green inspissated mass in the distal ileum points to the dx of…
meconium ileus
what would cause a decrease in airflow resistance, leading to supernormal expiratory flow rate?
ILD progressing to pulmonary fibrosis with thickening and stiffening of the pulmonary interstitium.
this causes increased lung elastic recoil, as well as airway widening due to increased outward pulling (radial traction) by the surrounding fibrotic tissue
Where does Fe absorption occur?
predominantly in doudenum and proximal jejunum
Where is vitamin C absorbed?
Where is pyridoxine absorbed?
distal small bowel through an active transport process
jejunum and ileum by passive diffusion
How are biotin and pantothenic acid adsorbed?
in small and large intestine via the Na-dependent multivitamin transporter; deficiency of either of these vitamins is rare
disease of young children that results in isolated idiopathic osteonecrosis of the hip
Legg-Calves-Perthes disease
What gene mutation is a/w McCune-Albright syndrome?
mosiac somatic mutation during embryogenesis in the GNAS gene encoding the stimulatory alpha subunit of G protein
mutation causes constitutive activation of the Gprotein/cAMP/adenylate cyclase signaling cascade
What are the abnormal symptoms associated with Legionella pneumonia?
- contaminated water source
- high fever
- relative bradycardia
- neuro ssx (HA and confusion)
- GI ssx
What is the MC lab abnormality a/w Legionella?
hyponatremia
may be related to inappropriate ADH secretion and/or renal tubulointerstitial disease
Pt presents with peripheral vision loss causing ‘near miss’ car accidents from both the L and R; all other testing is normal on exam
dx?
what would be other ssx commonly missed?
bitemporal hemianopsia
consider pituitary tumor
prolactinomas can cause galactorrhea and amenorrhea in women while in males they present with hypogonadism
consider what when a pt under the age of 50 presents with hypercoagulability who present with thromboses in the absence of any obvious explanations
inherited causes
Factor V Leiden mutation and mutations in the prothrombin gene are the MC inherited causes of hypercoagulability
pts plasma is resistant to the normally antithrombotic effects of activated protein C
dx?
mutation in Factor V gene, which renders factor Va resistant to inactivation by activated protein C
What is the MCC of aPTT prolongation?
Lupus anticoagulants
(seen in antiphospholipid antibody syndrome)
cells that are large with overlapping nuclei containing finely dispersed chromatin, giving them an empty or ground-glass appearance; numerous intranuclear inclusions and grooves can be seen; psammoma bodies can also be present
papillary carcinoma
partial opioid receptor agonist that binds with high affinity but has low intrinsic activity
in pts on long-term opioid tx, what can happen if they take this drug?
buprenorphine
displaces other opioids and precipitates withdrawal
….. uses CCR5 for viral entry and is considered ….. because CCR5 is expressed in high concentrations on both …. and lymphocytes
…. is the predominant HIV type
R5 virus
macrophage-tropic
macrophages
R5
….. uses CXCR4 for viral entry and is considered ….. because CxCR4 is expressed primarily on T lymphocytes but only …..
X4 virus
T lymphotropic
minimally on macrophages
HIV tropism is determined by a gene sequence in the variable (V3) region of the …
which encodes for the HIV surface ….
what does that do?
env gene
glycoprotein 120 - mediates viral attachment to the CD4 receptor and chemokine coreceptor
where do the majority of anal fissures occur?
why there?
posterior midline of the anal verge
likely due to the relatively poor perfusion of the posterior anal canal, which makes its mucosa sensitive to trauma and slows healing times
acute ischemic stroke affecting the angular gyrus of the dominant parietal lobe, a brain region supplied by the middle cerebral artery
dx?
what are presenting ssx?
Gerstmann syndrome
agraphia, acalculia, finger agnosia, L-R disorientation
can also be a/w alexia and aphasia
referred pain to the shoulder due to peritoneal irritation is called
Kehr sign
Niacin can be synthesized endogenously by…
This vitamin is an essential component of what?
tryptophan
NAD and NADP
What are these precursors for?
arginine
carotene
cholesterol
orotic acid
phenylalanine
- arginine
- nitric oxide, urea, ornithine, and agmatine
- also needed for formation of creatine
- carotene
- Vitamin A
- cholesterol
- steroid hormones
- orotic acid
- pyrimidine
- phenylalanine
- tyrosine, needed for catecholamines
What happens to PTH, active vitamin D, and urinary calcium levels in multiple myeloma?
low PTH and active vit D
elevated urinary calcium
young obese women with daily headache, bilaterally symmetric papilledema, and transient visual disturbances related to impaired cerebral venous outflow and elevated ICP
idiopathic intracranial hypertension (pseudotumor cerebri)
How does increased ICP affect the optic nerves?
increased ICP compresses the optic nerves, resulting in impaired axoplasmic flow and optic disc edema
What drugs would imitate physiologic insulin release?
combo long acting and rapid acting insulin
glargine - replicate basal insulin
lispro - given with meals to control postprandial glucose elevations
surface marker characteristically expressed on monocytes and macrophages, serves as a receptor for LPS (binding of LPS to this receptor results in activation of macrophage)
CD14
Rhabdomyolysis labs
elevated CK, and myoglobinuria (positive urine dipstick for blood without RBCs on microscopy)
Warfarin induced skin necrosis occurs how?
Warfarin inhibits proteins C and S (natural anticoagulants), which can lead to skin necrosis, particularly in patients with protein C or S deficiency
Where does colchicine inhibit part of the arachidonic acid pathway?
reduces formation of leukotriene B4/ leukocyte attraction
risk factors for diverticulosis include
diet high in red meat and fat and low in fiber, as well as obesity, physical inactivity, and smoking
amorphous extracellular matrix with scattered stellate or globular myxoma cells within abundant mucopolysaccharide ground substance would be seen in what type of tumor?
myxoma, most common primary cardiac neoplasm
physical exam of a pt with an atrial myxoma would often have
mid-diastolic murmur (tumor plop) that results from the motion of the tumor mass obstructing the mitral valve orifice
A left shift of the oxygen-hemoglobin dissociation curve will cause what?
affinity of hemoglobin for oxygen is increased - this will reduce the ability of hemoglobin to release oxygen within the peripheral tissues; low O2 levels stimulate compensatory erythrocytosis
pts are typically asymptomatic at that point
What are the disease states that are results of mutations that can cuase the production of hemoglobin with high oxygen affinity?
hemoglobins Chesapeake and Kempsey
age related change compensating for myopia (increased eye axial length, image focused in front of retina), allowing vision to improve
presbyopia - inability to focus on near objects - progressive denaturation of lens proteins and changes in lens curvature cause the lens to become less elastic and lose its accomodating power (image will focus behind the retina)
causes of restrictive cardiomyopathy
idiopathic or caused by infiltrative diseases (amyloidosis, sarcoidosis, hemochromatosis), radiation fibrosis, or endomyocardial fibrosis
endomyocardial biopsy typically revealing cross-striations of normal myocardial cells with other areas of myocardium infiltrated by an amorphous and acellular pink material
senile systemic amyloidosis
What is the best indicator for severity of mitral regurg?
S3
the absence of S3 can exclude severe chronic MR
pts with severe MR develop left-sided volume overload with an S3 gallop due to the large volume of regurgitant flow reentering the ventricle during mid-diastole
What things do you need for production of cholesterol gallstones?
increased cholesterol
decreased bile acids
decreased phosphatidylcholine
What drugs have the highest likelihood of causing drug-induced lupus erythematosus?
procainamide and hydralazine
anemia in lead poisoning is due to…
inhibition of ferrochelatase and delta-aminolevulinic acid (ALA) dehydratase in the heme biosynthesis pathway
because protoporphyrin IX cannot combine with Fe2+ to form heme due to ferrochelatase inhibition, it instead incorporates a zinc ion, leading to elevated zinc protoporphyrin levels
in addition, ALA levels are increased
Why does AKI occur in rhabdomyolysis?
What appears in the urine?
due to myoglobin degradation and heme pigment release; heme pigment causes ATN through direct cytotoxicity and renal vasoconstriction (ie ischemia)
injured tubular epithelial cells, with their deeply pigmented, randular contents, slough off into the tubular lumen, forming granular muddy brown casts
heme pigment in myoglobin cross-reacts with the urine dipstick reagent that detects hemoglobin, leading to a false-positive result for blood in the urine; however, micro shows no RBCs
prophylaxis for HIV pt from MAC
weekly azithromycin
recommended for HIV pts with CD4 ct less than 50
physical findings of azoospermia, small/firm testes, absent secondary male characteristics (including deep voice, beard, and male-pattern pubic hair), and tall stature; gynecomastia is also common
dx?
what does gynecomastia cause an increased risk for?
primary hypogonadism
increased risk of malignant transformation
What are the hormone levels in Klinefelter syndrome?
atrophied, hyalinized seminiferous tubules (resulting in low inhibin levels) and damged leydig cells (resulting in low testosterone); lack of FB inhibition results in excess gonadotropins (increased FSH and LH), which in turn will increase estrogen levels
intense lymphocytic infiltrate, often with germinal centers; residual follicles may be surrounded by Hurthle cells (large oxyphilic cells filled with granular cytoplasm
this is the histology seen with what disease?
chronic lymphocytic (hashimoto) thyroiditis
high levels of dietary alfatoxin exposure is associated with what?
G:C to T:A transversion in codon 249 of the p53 gene, which greatly increases risk of hepatocellular carcinoma
actions of the rotator cuff muscles
infraspinatus - external ro
supraspinatus -abduction
teres minor - adduction and external ro
subscapularis - adduction and internal ro
What happens to PaCO2 in a panic attack?
hyperventilation results in decreased PaCO2
hypocapnia can cause decreased cerebral perfusion with neuro sequelae
Drug to give pt with post-surgery urinary retention?
What should you not give?
bethanechol - muscarinic agonist to contract detrusor muscle
oxybutynin - antimuscarinic agent used for urge incontinence
duration of action of common benzos
- short
- triazolam, midazolam
- intermediate
- oxazepam, alprazolam, lorazepam, clonazepam
- long
- diazepam, chlordiazepoxide, flurazepam
assuming a normal rate of metabolic CO2 production, hypocapnia implies
alveolar hyperventilation
First line tx for psoriasis plaques
topical corticosteroids and vitamin D analogs (calcipotriene, calcitriol)
How do you identify PCP pna?
cannot be cultured, so dx requires ID in resp. secretions; methanamine silver stain is frequently used to identify the cell wall - crescent, crushed ping pong ball, or circular ring around clear center
histo of small intestine mucosa contain enlarged, foamy macrophages packed with both rod-shaped bacilli and PAS positive, diastase-resistant granules (which consist of lysosomes and partially digested bacteria)
Tropheryma whippelii
cardiovascular and renal presentations of SLE
- CV - accelerated atherosclerosis, small-vessel necrotizing vaculitis, pericarditis, and Libman-Sacks endocarditis (small sterile vegetations on both sides of the valve)
- renal - diffuse proliferative glomerulonephritis (diffuse thickening of the glomerular capillary walls with “wire loop” structures on light microscopy
fever, maculopapular rash, and acute renal failure occuring within a few weeks of starting a beta-lactam abx are highly suggestive of…
drug-induced acute interstitial nephritis
Acute interstitial nephritis is mediated by what? what does this involve?
mediated either by IgE or cell-mediated (IV HS rxn)
invovles renal interstitium, causing interstitial edema and leukocyte infiltration, granuloma formation can be observed
How are GFR and Cr related?
when GFR is normal, relatively large decreases in GFR result in only small increases in serum Cr.
when GFR is significantly decreased, small decrements in GFR produce relatively large changes in serum concentration
—- every time GFR halves, serum Cr doubles
