Last gasp Flashcards
(276 cards)
1
Q
GU infection with penile discharge, but without lymphadenopathy, shows neutrophils but no organisms on gram stain? Treatment?
A
Nongonococcal urethritis, likely Chladymia trachomatis; treat with bacterial protein synthesis inhibitor like azithromycin. If complicated (i.e., epididymitis), use two weeks doxyxycline
2
Q
Probenecid inhibits? (2) Uses?
A
Organic anion transporter - block penicillin excretion in the renal proximal tubule
Urate transporter - block uric acid reabsorption in the renal proximal tubule
3
Q
Smoker faints during coughing fit?
A
Decreased cerebral perfusion due to decreased venous return to the heart (cough-induced syncopy); caused by increased intrathoracic pressure –> transient decrease in cardiac output
4
Q
Patient has numerous fleshy skin nodules for years and years, as well as axillary freckling. What are they and what are they made of?
A
Neurofibromas - loose, disorganized proliferations of Schwann cells, fibroblasts, and neurites
5
Q
Dysmenorrhea, dyspareunia, pelvic pain, and infertility in a womon of reproductive age suggest?
A
Endometriosis - ectopic growth of endometrial glands and stroma in the peritoneum and pelvic organs.
6
Q
Cramping, bloody diarrhea, friable, inflamed mucosa in the rectum and sigmoid colon?
A
Ulcerative colitis - also going to find neutrophils in the crypt lumina
7
Q
Patient with depression tries a new medication. What is it, what to watch out for?
A
SSRIs are first line treatment for depression. If those don’t work, try TCAs like amitriptyline. SE include anticholinergic, antihistaminic, and alpha-adrenergic antagonist effects. Can also affect cardiac conduction.
8
Q
Most common cause of Restriction Fragment Length Polymorphism (RFLP)?
A
Single nucleotide polymorphisms (SNPs)
9
Q
PCI intervention to place a drug-eluting stent - what two drugs might be used? Purpose?
A
Paclitaxel and sirolimus - antineoplastic agents to inhibit intimal hyperplasia.
10
Q
Only RNA virus to replicate in the nucleus (other than retroviruses)?
A
Influenza - orthomyxovirus, 8 segments
11
Q
Most common urea cycle disorder? Enzyme deficiency? Accumulated intermediate?
A
Ornithine transcarbamoylase deficiency (OTC, congenital hyperammonemia) - carbamoyl phosphate piles up, gets converted to orotic acid
12
Q
Polypeptide triple helix? Structure?
A
Collagen - 3 pro-alpha chains held together by hydrogen bonds. Each chain has repetitive amino acid sequence represented as Gly-X-Y.
13
Q
Function of glysine in collagen sequence?
A
compact coiling of the helix
14
Q
Describe transduction?
A
process by which bacterial DNA is transported from one bacterium to another by a virus (bacteriophage).
15
Q
What happens if a bacteriophage accidentally grabs some bacterial DNA and packs it in the viral capsid?
A
Virus will still be infective, so the phage transports host bacterial DNA to the newly infected bacterium. However, the bacterial DNA likely displaced viral genome , so new progeny virions will be synthesized. The bacteria will just degrade the virus and new DNA, or perhaps incorporate the new DNA into its own (transduction).
16
Q
What type of herniation leads to fixed, dilated pupil? Also will see?
A
Uncal herniation - compression of the oculomotor nerve causing ipsilateral sign. Can also see contralateral muscle paresis due to direct compression of the ipsilateral cerebral peduncle by the herniated temporal lobe.
17
Q
Hereditary diseases showing anticipation?
A
Trinucleotide repeat disorders - Huntington, myotonic dystrophy, fragile X, spinocerebellar ataxia
18
Q
Endocrine organ contributing most to bone injury via osteoporosis?
A
Ovary - estrogen. Not parathyroid - primary hypoparathyroidism leads to low serum calcium, but it does not have a dramatic net effect on mineral density, as low PTH causes decreased bone resorption.
19
Q
Microsatellites are? Are not?
A
Microsatellites are repeating sequences of DNA of set length (i.e., CACACACA) normally found in the human genome. These microsatellites vary from person to person, but are faithfully conserved during DNA replication.
Microsatellite repeats are NOT trinucleotide repeats - no relation to Huntingtons, despite question direction.
20
Q
What is microsatellite instability? Associated conditions?
A
Instability is defined as abnormal lengthening or shortening of microsatellite repeats – Various syndromes such as hereditary nonpolyposis colorectal cancer.
21
Q
Someone has a rash that looks like Shingles, but it’s not the first time? Different locations?
A
Immunocompromised, HIV or whatever - the Varicella Zoster virus keeps reemerging on different dermatomes. There’s also a disseminated varicella zoster disease!
22
Q
Enzyme activity contributing to osteoarthritis?
A
Relative overactivity of metalloproteases in the joint space.
23
Q
Most common opportunistic viral infection affecting the gi tract of HIV patients?
A
Cytomegalovirus (a herpes virus) - CMV colitis is second most common reactivation syndrome after CMV retinitis.
24
Q
HIV patient presents with fever, anorexia, weight loss (low BMI), and abdominal pain, viral etiology suspected? Biopsy findings?
A
CMV colitis - Histology shows acute and chronic inflammatory changes, vasculitis, and giant cells with large ovoid nuclie containing centralized intranuclear inclusions - the image will show a cell that looks like a bull’s eye or may be described as a (very dilated) owl’s eye.
25
Candida or histo causing colitis?
Not likely, try again.
26
A treatment that mucks around with gp41 or gp120 in an HIV patient inhibits what?
Membrane fusion - those are the proteins HIV uses to gain entry, binding happens via CCR5 or CXCR4 receptors binding CD4 on the T cell.
27
No chest pain, dyspnea, or suggestion of heart failure, but lots of pitting edema bilaterally and maybe a mass in the abdomen? Slow development means?
Inferior vena cava obstruction, the mass is probably a renal tumor that has spread and caused a thrombus (the obstruction is not related to mass effect of the tumor, oddly enough). In a slowly developing obstruction, collateral veins will become prominent in the abdominal wall.
28
Patient with renal cell carcinoma, endocrine finding?
Excess erythropoietin production by the tumor --> erythrocytosis
29
NRTI MoA? Name them (7)?
Competitive nucleoside/tide reverse transcriptase inhibitor: abacavir and tenofovir plus emtricitabine, didanosine, stavudine, lamivudine, zidovudine
30
NNRTI MoA? Name them (2)?
Allosteric reverse transcriptase inhibitor: efavirenz, nevirapine ("-vir-"
31
Protease inhibitor MoA? Name them (4)?
Inhibit HIV polyprotein cleavage: Atazanavir, darunavir, indinavir, ritonavir ("-navir")
32
Integrase inhibitor MoA? Name them (2)?
Inhibits HIV DNA integration into host genome: Dolutegravir, raltegravir ("-gravir")
33
Fusion inhibitor MoA? Name one?
Inhibitis HIV fusion with target cell membrane by binding to HIV gp41: Enfuvirtide ("-fu-")
34
CCR5 antagonist MoA? Name one?
Inhibits HIV entry by allosteric blocking of HIV gp120 interaction with CCr5 (tropism testing required)
35
HIV pol gene encodes for?
HIV viral protease, integrase, and reverse transcriptase
36
How does HIV gain resistance to the protease inhibitors?
Point mutations in the viral protease region of the HIV pol gene
37
Cerebellar mass turns out to be hemangioblastoma. Likely diagnosis? Inheritance pattern? Associated conditions?
This is Von Hippel-Lindau (VHL), an autosomal dominant disease - mutation in tumor suppressor on chromosome 3 - characterized by hemangioblastomas in the cerebellum and retina, cysts in the kidneys and pancreas, pheochromocytoma, and renal cell carcinoma
38
2,3-BPG effect on hemoglobin? Low amounts?
binds deoxygenated hemoglobin in the taut conformation - tends to push oxygen into peripheral tissue, shifting O2 dissociation curve to the right when present. If 2,3-BPG is low, this promotes holding oxygen on the hemoglobin, a left-shifted dissociation curve
39
In what part of the eye does copper accumulate in Wilson's Disease? Other organs involved?
Cornea - liver, brain, kidney (and eye)
40
Cause of hemolytic anemia in a patient with CF?
Vitamin E deficiency - high O2 content of RBCs contributes to membrane oxidation
41
Breast biopsy describes an encapsulated proliferation of stromal and ductal elements. Corresponding clinical findings?
This is a fibroadenoma - presents in adolescent girls and young women. Typically a solitary, nontender, firm, well-demarcated, spherical, mobile nodule that changes in size in response to estrogen stimulation.
42
Flumazenil does what? But doesn't do what?
Competitive inhibitor of benzodiazepines at the GABA receptor. Does not inhibit barbiturates.
43
Two major drugs that potentiate GABA channel-mediated chloride conductance?
Benzodiazepines and barbiturates
44
Rhombencephalon becomes?
metencephalon --> pons, cerebellum, upper 4th ventricle
| myelencephalon --> medulla and lower 4th ventricle
45
Mesencephalon becomes?
midbrain and aqueduct
46
Prosencephalon becomes?
Telencephalon --> Cerebral hemispheres and lateral ventricles
Diencephalon --> Thalamus and 3rd ventricle
47
Alcoholic can do finger-to-nose but not heel-to-shin?
Cerebellar ataxia - remember the body maps onto the brain somatotopically - the lower body is in the middle (vermis) and the upper body is in the cerebellar hemispheres
48
What's a leucine zipper?
Class of eukaryotic transcription factors composed of 2 alpha-helical proteins tha combine to form a diner, binds to negatively-charged DNA in the major groove
49
Describe a Reed-Sternberg cell?
This is the prototypical "two fried eggs" appearance or "owl eyes" that is indicative of Hodgkin Lymphoma. Be careful! Sometimes the bilobed nucleus can look like two entire cells, rather than two nuclei in the same cell! They'll show you a crappy staining job where the cell outline is indistinct to trick you.
50
Role of phospholipase C in Gq (phosphatidylinositol) system?
Cleaves PIP2 to DAG and IP3. IP3 triggers calcium release from the ER, which is largely responsible for activating protein kinase C --> physiologic effect
51
Do novo synthesis of purines and pyrimidines occurs where?
Cytosol
52
Psoas sign?
Psoas is a hip flexor muscle - flex hip against resistance applied at knee. Positive sign (pain) indicates inflammation (abscess, appendicitis) of the psoas muscle or the overlying parietal peritoneum.
53
Question asks about amphotericin B? Where exactly does it work, and how? Maybe mentions use in cryptococcus infection?
Amphotericin B binds ergosterol, which results in forming pores in the cell membrane. Trick - this isn't the outer layer of the organism, as there is a cell wall outside of the membrane, and then a capsule! - so the site of action is not on the surface, but two layers deep, where the membrane is.
54
Fungal drug that targets the cell wall? Where is this located?
Echinocandin agents (caspofungin) inhibit cell wall synthesis - the cell wall is outside the membrane, under the capsule (if there is one).
55
What distinguishes nephritic from nephrotic syndrome?
Presence of hematuria - you'll still see at least mild proteinuria in nephritic syndrome, but no RBCs in nephrotic syndrome
56
Chromosomal makeup of a complete mole? Pathology shows? Which stain? Proliferative tissue?
46,XX or 46,XY - both sex chromosomes from paternal donor (partial mole is 69,XXX or 69,XXY). On pathology with p57 stain, see edematous chorionic villi due to proliferation of cytotrophoblasts.
57
topical retinoid indication and mechanism of action?
Treatment of comedonal acne - structural analogs of vitamin A, act to decrease sebum production and normalize epidermal differentiation via increased cellular turnover and shedding of cells from the stratum corneum --> opens blocked pores, prevents formation of microcomedones
58
Three apertures in the diaphragm?
Vena caval foramen - IVC at T8
Aortic hiatus - aorta, thoracic duct, and azygos vein at T10
Esophageal hiatus - esophagus and the anterior/posterior trungs of the vagus nerve at T12
59
Only lysosomal storage disease that presents with cardiomegaly in infancy? Deficiency?
Pompe disease - deficiency of alpha-glucosidase.
60
Gynecoid body habitus?
gynecomastia, adiposity at hips and thighs --> think Klinefelter syndrome (47, XXY) --> primary hypogonadism
61
Characteristics of a pontine hemorrhage?
comatose patient with pinpoint pupils and rigid, extended upper and lower extremeties (decerebrate posturing) - death within hours
62
Tumor raises ICP how?
Two mechanisms - disruption of the BBB (vasogenic edema) or obstruction of CSF flow (hydrocephalus)
63
Describe cytotoxic edema in the brain?
Increase of intracellular fluid within neurons, glia, and endothelial cells that happens when cellular injury impairs membrane Na+/K+-ATPase typically following ischemic insult
64
What predisposes the cervix to oncogenic effects of HPV?
The transition zone is an area of metaplasia where both types of cervical epithelia are present and undergo transformation from one type to the other over time. Lots of active division taking place.
65
First sign of tetanus poisoning?
Patient has difficulty opening and closing jaw - leads to "lock jaw" --> eventual risus sardonicus, etc.
66
How does hypercalcemia cause dehydration?
Down-regulation of the expresion of water channels in the collecting tubules (not osmotic diuresis)
67
Class III antiarrythmic with class I-IV properties?
Amiodarone
68
Class III antiarrythmic with beta blocker properies?
Sotalol
69
General action of Class III antiarrythmics?
K+ channel blockers - prolong plateau (phase 2)
70
Someone with heart condition now has trouble seeing? Halos?
Gray corneal microdeposits due to amiodarone
71
Amiodarone effect on thyroid?
Variable, due to iodine
72
Worst amiodarone SE?
Pulmonary fibrosis
73
Test to monitor during treatment with amiodarone?
LFTs
74
Torsades with Class III?
sotalol, dofetilide, and ibutilide induce torsades via wide QT. Amiodarone also widens QT, but no torsades, prolly due to blocking more than just K+ channels.
75
Name 4 Class III agents?
Amiodarone, sotalol, dofetilide, ibutilide
76
Which are the Class IV antiarrythmic agents?
Non-dihydropyridine calcium channel blockers diltiazem and verapamil
77
Cardiac arrythmia treated by Class IV agents?
Atrial afibrillation
78
Don't use Class IV agents with? Why?
Beta blockers, other SA/AV node depressants, someone with history of conduction defect (i.e. Wenkebach or similar) - can induce heart block
79
Quick treatment for torsades de pointe?
Magnesium infusion, even if Mg++ serum levels are normal
80
Adenosine MoA treating arrythmia?
Activates inhibitory A1 receptors on the myocardium and at the SA and AV nodes --> increased outward K+ current and suppression of inward Ca++ current --> hyperpolarization
81
Calcium-dependent action potentials?
AV node - inhibited by adenosine - increased refractory condition --> very short-lived heartblock (10 second half-life of adenosine)
82
Transposition of the great vessels - embryonic failure?
Failure of the aorticopulmonary septum to spiral normally - not related to apoptosis or obliteration
83
Fundoscopic exam reveals bright red spot in the macula? (2)
Worry about:
1) Tay-Sachs - beta-hexosaminidase A deficiency with GM2 accumulation
2) Niemann-Pick - Sphingomyelinase deficiency with accumulation of sphingomyelin
84
Neurological syndrome associated with B12 deficiency?
Abnormal myelin synthesis:
1) Dorsal columns lost bilaterally --> position and vibration gone
2) Lateral corticospinal tracts --> upper motor neuron signs
3) Axonal degeneration of peripheral nerves --> numbness/paresthesias
85
lymph node waxes and wanes, no other particular complaints?
Follicular lymphoma - most common indolent non-Hodgkin Lymphoma.
86
Histology of lymph node reveals a blue blob that is split kind of like the grand canyon?
This is a cleaved follicle center -- highly suggestive of follicular lymphoma with t(14;18)
87
visual field has a small black spot on one side?
Monocular scotoma, due to a partial retinal lesion
88
Homonymous hemianopia, no macular sparing?
Lesion downstream of the optic chiasm prior to spread of the optic transmission (optic tract)
89
Homonymous hemianopia, macular sparing?
Posterior cerebral artery lesion. Macula is spared because of collateral blood supply by the middle cerebral artery to the occipital pole
90
What do you need to know to make a PCR primer? What is irrelevant?
Need to know the oligonucleotide sequence of the flanking regions of the DNA of interest - that way you amplify only the target DNA, not everything else. You don't need to know that actual DNA sequence you are replicating, the polymerase takes care of that with the substrates.
91
Best way to start discussion about non-adherence to medication schedule?
Normalize the feeling of difficulty - "Many patients find it difficult to take medication every day; tell me more about what makes it hard for you."
92
Dobutamine MoA? Indication?
Beta adrenergic agonist, predominantly beta 1. In cardiac myocytes, increased cAMP causes calcium channel activation and increased cytosolic Ca++ concentration --> positive inotrope.
93
Discuss alpha-1 versus beta-2 action in the vasculature
alpha-1 is Gq --> agonism results in increased intracellular Ca++ in smooth muscle --> vasoconstriction
beta-2 is Gs --> agonism results in activation of Protein kinase A, which facilitates uptake of Ca++ by sarcoplasmic reticulum of smooth muscle --> vasodilation
94
Beta receptor effect in cardiac versus smooth muscle?
Both targets see increased cAMP via activation of adenyl cyclase
Cardiac muscle: Ca++ channel activation leads to increased cytosolic [Ca++] --> positive inotrope
Smooth muscle: cAMP-dependent protein kinase leads to augmented Ca++ uptake by SR --> relaxation
95
Patient has something with CMV involvement and now there is talk of resistance. What's going on? If a new medication is tried, SE?
CMV can become resistant to gancyclovir due to mutation in viral thymidine kinase. Alternate therapy is Foscarnet, but foscarnet can chelate calcium and induce renal wasting of magnesium --> seizures
96
Immune system component missing from the CNS?
No complement components of the alternative pathway --> impaired phagocytosis of invasive organisms.
97
What is the target of antibodies in Goodpasture Syndrome? Useful conclusion?
alpha3-chain of collagen type IV (found in the glomerular basement membrane, of course). Can do a serum antibody test with patient serum and synthetic alpha3-chain to test for Goodpasture
98
Airflow shows periodic breathing spells separated by no breathing?
Cheyne-Stokes breathing - periods of apnea followed by gradually increasing then decreasing tidal volumes until recurrence of apnea - commonly seen in patients with advanced congestive heart failure.
99
Study of a patient with obstructive sleep apnea shows what on airflow pattern?
Constant airflow pulsations separated by periods of apnea - however, thoracic and abdominal movement does not stop, as in Cheyne-Stokes breathing
100
Clinical presentation suggest renal dysfunction (high creatinine, oliguria or similar) plus an intranasal ulcer that won't heal? Lab finding?
Granulomatosis with polyangiitis (Wegener's) - find c-ANCA, 90+% specific. The intranasal ulcer counts as "upper respiratory tract" or "nasopharynx" involvement
101
Describe the bit of the optic nerve path that fans out? Associated visual defects?
After the optic chiasm, the dual optic nerves travel to the Lateral geniculate nucleus of the thalamus. From here, the efferent fibers spread out into an "upper, outer" section (when viewed on cross section) called the Meyer's loop and an inner section called the Dorsal optic radiation.
Meyer's Loop affected --> homonymous superior quadrantanopia ("pie in the sky" defect)
Dorsal optic radiation affected --> homonymous inferior quadrantanopia ("pie on the floor" defect)
102
Th2 cells secrete? Results in?
IL-4, 5, 10, and 13 --> activate B cells (humoral immunity), promote class-switching, secretion of antibodies
103
Th1 cells secrete? Results in?
IL-2, IFN-gamma, lymphotoxin beta --> activate macrophages and cytotoxic T-cells (cell-mediated immunity) --> cytotoxicity, delayed hypersensitivity
104
What's a Th0 cell? Receptors present?
"Naive" T-cells -- hasn't yet contacted antigen. Possess T-cell receptor, CD3, CD4 proteins on cell surface. Activation results in differentiation into Th1 or Th2
105
Role of CD3 on Th0?
When activated, transmits signal to cell's interior
106
What pushes a Th0 cell to be a Th1 cell?
IL-12 produced by macrophage
107
What pushes a Th0 cell to be a Th2 cell?
IL-4 released by non-macrophage APCs
108
Someone with a dog now has diarrhea but Y. enterecolyticas isn't a choice?
Campylobacter can be transmitted from domestic animals to humans. Diarrhea will become bloody, possible Guillane-Barre.
109
Back pain worse at night suggests? Anelgesics?
Metastatic process - analgesics and rest not effective to reduce pain, so not degenerative disease. They might or might not mention systemic symptoms.
110
Patient with CF shows decreased proprioception and hyporeflexia? Related finding?
Vitamin E deficiency - Neurons with long axons (i.e. dorsal columns) are susceptible to oxidative stress damage to membrane due to massive surface area. Vitamin E is anti-oxidant. See hemolytic anemia due to erythrocyte membrane stress from high O2 concentration
111
Percentage of occlusion necessary to precipitate stable angina?
> 75% (apparently, even 50% occlusion will not result in clinical symptoms of angina, on exertion or otherwise)
112
What are the frozen stages in oocyte development?
Childhood to puberty: oocytes arrested in prophase of meiosis I.
Ovulation: LH surge triggers completion of meiosis I of several primary oocytes with first polar body ejection and degeneration. Only one oocyte should be released (but we do see non-identical twins, triplets, etc.) now arrested in metaphase of meiosis II.
Fertilization: completion of meiosis II and generation of polar body
113
Large vessel vasculidities (2)?
Takeyasu and Temporal (extension of same disease, though presentation is different)
114
Medium vessel vasculidities (2)?
Polyarteritis nodosa and Kawasaki
115
Small vessel vasculidities (3)?
Churg-Strauss
Wegener's (Granulomatosis with polyangiitis)
Henoch-Schonlein Purpura
116
Patient has a recurrence of an illness, but this time it's worse, with fever, rash, hepatomegaly? Organism? Vector?
Consider Dengue Fever - four serotypes, first time around isn't too bad, next infection with different serotype can be much worse. Single-stranded RNA Flavivirus transmitted by Aedes mosquito
117
Bone type involved in osteoporosis? Specific finding?
Osteoporosis primarily involves trabecular (spongy) bone - trabecular thinning due to imbalance between osteoclast and osteoblast activity characterized by the persistence of primary, unmineralized spongiosa in the medullary canals.
118
What type of signalling system does Ca++ stimulate to regulate secretion of PTH? Congenital disorder?
G-protein-coupled (metabotropic) receptor; Familial hypocalciuric hypercalcemia is a benign autosomal dominant disorder caused by defective CaSR in the parathyroid gland and kidneys --> mild, asymptomatic hypercalcemia, reduced urinary excretion of calcium, high normal or mildly elevated PTH
119
Where is copper level low in Wilson's disease?
Decreased secretion of copper into the biliary system
120
Copper mechanism of injury in Wilson Disease?
Pro-oxidant, causes production of free radicals that damage membranes, etc.
121
Site of copper deposition in Wilson Disease?
liver, basal ganglia, cornea
122
Ulcers in someone taking methotrexate? Parallel conditions?
MTX functions as a chemotherapeutic agent through inhibition of DNA synthesis and as an enti-psoriasis agent through immunomodulatory effects on activated T cells. However, MTX causes death of all rapidly dividing cells, particularly those of the GI mucosa (-> apthous ulcers) and bone marrow (-> pancytopenia)
123
Patient took to much MTX. What to do?
Give folinic acid - serves as a reduced form of folic acid that bypasses DHFR in conversion to THF, so no MTX effect to stop production of THF as MTX does to normal folate.
124
Diabetes patient has lens opacity. Pathway?
Hyperglycemia --> Polyol pathway in lenses (cataracts), retina (retinopathy), renal papilla (nephropathy), and Schwann cells (neuropathy)
Glucose is converted to Sorbitol by Aldose reductase
Sorbitol is converted to Fructose by Sorbitol dehydrogenase
Paucity of sorbitol dehydrogenase dehydrogenase leads to sorbitol accumulation. Sorbitol is osmotically active --> water influx --> damage
125
Normal site where polyol pathway is used?
Seminal vesicles - sperm use fructose as their primary energy source
126
Relevant enzyme in xeroderma pegmentosum? Does what, exactly? Follow-up?
UV-specific endonuclease; Recognizes distortions in the structure of DNA caused by thymine dimers, subsequently excises stretches of single-straned DNA with the defects. DNA polymerase uses the opposite (remaining) strand as a template to fill the gap. DNA ligase seals the new strand.
127
Function of 3' -> 5' exonuclease activity?
This is the "proofreading" ability of DNA polymerase - allows for the recognition and repair of mismatched bases during DNA replication
128
Mechanism for synchronizing activity of multiple enzymes?
All are activated by Ca++, so influx of calcium activates them at the same time.
129
Skeletal muscle needs energy to contract. Mechanism to get glycohenolysis?
Increased intracellular calcium (i.e., as part of contraction) activates phosphorylase kinase, stimulating glycogen phosphorylase to increase glycogenolysis.
130
Patient is undergoing aggressive diuresis due to elevated ICP after trauma. Now they have trouble breathing? Other SE to watch?
Diuresis likely performed with mannitol, which acts to pull water into the vasculature from tissue, and then trigger osmotic diuresis in the proximal tubule and loop of Henle. Rapid volume increase in the vasculature increased hydrostatic pressure sufficiently to cause pulmonary edema.
May also see dilutional hyponatremia and metabolic acidosis, and hyperkalemia due to high volume diuresis.
131
Direct mechanism of narcolepsy? Associated phenomena?
Depletion of hypocretin-secreting neurons in the lateral hypothalamus that are involved in maintaining wakefulness; Individuals commonly experience intrusions of REM sleep phenomena during sleep-wake transitions, including hypnagogic (upon falling asleep) and hypnopompic (upon awakening) hallucinations and sleep paralysis (inability to move immediately after awakening).
132
Confirmation test for narcolepsy?
Low CSF levels of hypocretin-1 or shortened REM sleep latency on polysomnography.
133
Most common cause of death in TCA overdose?
TCAs such as amitriptyline inhibit the reuptake of norepinephrine and serotonin, making them useful for the treatment of depression. They inhibit fast sodium channel conduction in cardiac myocytes (and the His-Purkinje system), slowing down myocardial depolarization and leading to cardiac arrhythmias, the most common cause of death in patients with TCA overdose. Secondarily, can experience refractory hypotension resulting from decreased cardiac contractilty and direct peripheral vasodilation due to peripheral alpha-1 adrenergic receptor antagonism.
134
Distinguish myoclonus and dystonia?
Myoclonus is a sudden, brief, shock-like muscle contraction. Dystonia is a neurological movement disorder characterized by sustained, involuntary muscle contractions - distortion of the body into abnormal and even painful postures.
135
Most common focal dystonia?
Cervical dystonia - also called spasmodic torticollis.
136
Excessive shoulder exercise (like pitching extra innings) may cause injury to what nerve? Nerve roots?
Musculocutaneous nerve, arises from C5-C7
137
Nerve that pierces a muscle in the upper arm? Nerve function?
Musculocutaneous nerve, pierces the coracobrachialis. Motor function for flex arm at elbow, supinate forearm; sensory innervation of the lateral forearm via the lateral cutaneous nerve of the forearm
138
Problem flexing the arm - which muscles?
biceps brachii, brachialis, and coracobrachialis
139
Sensory innervation of the medial forearm?
medial cutaneous nerve of the forearm, a branch of the medial cord of the brachial plexus
140
First area of brain damaged during global cerebral ischemia?
Hippocampus - most vulnerable cells cells are the pyramidal cells of the hippocampus and neocortex, followed by the Purkinje cells of the cerebellum
141
Describe visual field mapping to the retina?
The temporal hemiretina "sees" the nasal visual field, while the nasal hemiretina "sees" the temporal field. For example, a lesion in the right temporal hemiretina will result in a visual field deficit in the right nasal visual field.
142
Difference between the hemiretinas in downstream signal conduction?
The temporal and nasal hemiretinas of the same eye go to opposite lateral geniculate body in the thalamus. The temporal hemiretina goes to the lateral geniculate body ipsilaterally, while the nasal hemiretina crosses to the contralateral lateral geniculate body via the optic chiasma
143
Inferior colliculus handles information for which sensory system?
Inferior colliculi and medial geniculate bodies are part of the auditory pathway.
144
True versus false diverticulum, examples of each?
True diverticulum possesses all three layers of intestinal wall (mucosa, submucosa, and muscularis) - i.e., Meckel's diverticulum and the appendix. False diverticulum possesses only two layers (mucosa and submucosa), as in Zenker's esophageal and common colon ticks.
145
Describe Meckel's diverticulum?
True diverticulum that is an embryonic remnant due to failure of obliteration of the omphalomesenteric (vitelline) duct).
Rule of 2s: 2% of population, 2 feet from the ileocecal valve (in the ileum), 2 inches in length, 2% are symptomatic, males 2 times more likely to be affected
146
Describe the proximate vascular structures to the ureters in female anatomy.
Arise retroperitoneally from the kidneys, pass just anterior to psoas muscle. Pass posterior to the gonadal arteries, then anterior to the internal and external iliac arteries.
147
"Water under the bridge"?
The uterine artery crosses over the anterior surface of the ureter.
148
Tamoxifen treatment details and likely SE? Alternative without this effect?
Selective estrogen receptor modulator. Down-regulates estrogen receptor on the breast, but upregulates ER in endometrial tissue, leading to development of endometrial hyperplasia and possibly endometrial cancer. Raloxifene is a SERM that does not agonize endometrial ER, so no hyperplasia/cancer effect.
149
HIV patient has diarrhea, colonoscopy shows multiple hemorrhagic polypoidal lesions? What shows up on biopsy of the lesions? Diagnosis?
Consider Kaposi's sarcoma (they won't mention the skin findings for some reason...). On biopsy, the lesions reveal spindle cells with surrounding blood vessel proliferation, which you would also see on biopsy of cutaneous kaposi sarcoma lesions.
150
Homebirth CF baby has intracranial bleed?
No vitamin K (not found in breast milk, poorly absorbed in gut since fat-soluble), decreased coagulation factor activity --> life-threatening bleeding diathesis
151
Parvovirus infection during pregnancy? Maternal symptoms?
High risk groups involve teachers and such - ssRNA, non-enveloped virus can cause interruption of erythopoiesis in fetus, leading to stillbirth. Maternal symptoms likely include arthralgias (joint pain).
152
Mitochondrial change seen in irreversible cellular injury? Reversible?
Appearance of vacuoles and phospholipid-containing amorphous densities --> no longer able to generate ATP via oxidative phosphorylation. Simple swelling is reversible.
153
Dibasic amino acid transporter defect?
The dibasic amino acids are cysteine, ornithine, lysine, and arginine (cola), and share the common transporter. Deficiency is not a problem (they can be absorbed as oligopeptides), but kidney stones are. If the transporter is defective, then these AA are not reabsorbed in the prosimal tubule, leading to formation of cystine kidney stones.
154
In a patient with hypertrophic cardiomyopathy, what physiologic effect increases murmur intensity?
Decreased preload - achieved by:
1) Valsalva maneuver (straining phase)
2) Abrupt standing (from supine or sitting)
3) Nitroglycerin administration
155
Mechanisms to increase afterload in a patient?
Sustained hand grip and squatting (from standing position)
156
Treatment for unconscious patient with severe hypoglycemia in a non-medical setting?
1) Glucagon shot --> increases hepatic glycogenolysis and gluconeogenesis
2) buccal or sublingual glucose/sucrose --> slow absorption, erratic, may not be effective
157
Actual mechanism to get beta cells to release insulin?
Glucose enters beta cells by facilitated diffusion via GLUT2 transporter. Oxidative metabolism --> generate ATP. ATP binds to the regulatory subunit of the ATP-sensitive K+ channel, which closes the channel (normally open) --> decreased K+ efflux leads to membrane depoloarization --> open the voltage-dependent calcium channels --> increased intracellular Ca++ --> insulin release!
158
liver mass biopsy shows big open spaces with RBCs?
Cavernous hemangioma - most common benign liver tumor
159
positive likelihood ratio?
Sensitivity/(1 - specificity) --> ratio of positive test result in people with disease to positive test result in people without disease (higher ratio is better)
- nicely independent of disease prevalence
160
lead time bias?
Earlier detection of a condition gives the illusion of improved long-term outcomes, but the course of disease and long-term outcome is actually unchanged
161
length-time bias?
Screening test preferentially under-diagnoses more aggressive disease forms (or over-diagnoses less aggressive forms) such that a study population appears to have a higher survival rate. In reality, there is no change in disease course or prognosis, just a type of sampling error.
162
What's a z score?
The z score is the ratio of a value in a data set to the standard deviation of the data set, i.e., the number of standard deviations away from the mean that a given value lies. Outlying values have high z scores in a tight data set.
163
Trick when asked "number of people or values outside 2 standard deviations?"
95% of values are inside 2 sigma, 5% are outside. This means that 2.5% are larger, 2.5% are smaller. Don't think of the 95% value and fall into the trap of thinking that 5% of values are above the 2 sigma cut-off.
164
What is type 1 error in a study? Type 2?
Type 1 --> wrongfully concluding the existence of an association where there is none
Type 2 --> Wrongfully concluding no association exists where an associate actually does exist
165
What is study alpha?
Probability of committing type 1 error, expressed as a p value -- alpha usually set to 0.05; p association exists!
166
histamine receptor in the nose?
H1 --> increased nasal/bronchial mucus production
167
receptor/molecule responsible for urticaria and hives?
H1, histamine
168
histamine function in the brain?
neurotransmitter associated with sleep and arousal, not mediated by mast cell release
169
diphenhydramine and dimenhydrenate MoA?
1st generation H1 blockers
170
antihistamine to treat motion sickness? SE?
1st generation antihistamines --> lipophilic --> enter CNS --> act on vestibular system
side effect of drowsiness
171
psych use for 1st generation antihistamines?
Treat EPS caused by antipsychotics
172
long-acting beta-2 agonist for moderate to severe persistent asthma? Why are they long-acting?
LABAs - salmeterol and formoterol; long-acting due to high lipid solubility
173
leukotriene blockers? Use?
montelukast and zafirlukast - LTD4 receptor antagonist - asthma treatment
174
theophylline? SE?
Alternative asthma therapy that has mostly fallen out of use. Methylxanthine (caffeine-like drug) works as a phosphodiesterase inhibitor (PDEI, like sildenafyl) to maintain increased cAMP --> bronchodilation; Narrow therapeutic window, CYP450 metabolized --> leads to tremor, racing heart, caffeine-overdose symptoms if some other drug trashes CYP450
175
monoclonal antibody against mast cells? Alternative against mast cells?
Omalizumab - actually binds Fc region of IgE
| Cromolyn sodium inhibits mast cell degranulation
176
Immediate bronchodilation in emergent situation?
Albuterol, escalated to nebulized ipratropium if necessary along with IV corticosteroids
177
Severe asthma attack in a child, treatment option?
Epinephrine (large dose) - also can use in refractory cases in non-children
178
most common type of bladder cancer worldwide? cause? what do you see?
squamous cell carcinoma - rare in US, but most common worldwide due to chronic irritation by eggs of helminth Schistosoma haemotobium
- see keratin pearls, meaning these are not transition cells
179
Transition cell carcinoma of the bladder caused by?
cigarette smoke, aniline dyes - TCC is most common bladder cancer in US
180
microglia embryologic origin? function?
arise from monocytes of mesodermal origin - phagocytes of CNS
181
papillary carcinoma histology and prognosis?
cold mass on scintiscan; psamoma body on histology, orphan annie eye nucleus; 10 year survival is 98%
182
multiple fractures, blue sclera dx? Inheritance? pathophysiology?
osteogenesis imperfecta; autosomal dominant; defect in Type 1 collagen, procollagen does not assemble
183
Subcutaneous anticoagulent? MoA?
Low Molecular Weight Heparin --> works by potentiating antithrombin III, which inactivates Factor Xa and throming; can be administerd outpatient
184
cystic ovarian mass and hyperthyroid?
Struma ovarii --> thyroid-hormone secreting ovarian teratoma
185
artery supplying Wernicke's area?
middle cerebral (not ACA)
186
most common primary cardiac neoplasm? histology?
atrial myxoma - amorphous extracellular matrix
187
male straddle injury with fluid in the scrotum? fluid in the retropubic space?
rupture of urethra below urogenital diaphragm versus above urogenital diaphragm
188
mechanism of kidney injury in SLE?
Type III hypersensitivity - accumulation of immune complexes in subendothelium activates complement, which is chemoattractive for neutrophils
189
Treatment for SLE in patients with organ involvement?
Cyclophosphamide --> often with glucocorticoids
190
weight gain, dyspnea, and edema signal? Virus tie-in?
CHF; after URI with coxsackie, HIV, influenza, adeno-, echo-, cyto-, etc; Can have dilated cardiomyopathy via direct cytotoxicity from receptor-mediated entry to myocytes
191
Non-viral mechanism of DCM?
sarcoid --> granulomatous inflammation --> DCM
doxorubicin (chemo) --> DCM
idiopathic, iatrogenic, alcohol
192
stones that show up on X-ray? Don't show up? Both will show up on?
-Calcium based show up on X-ray --> suggest increased PTH/hyperparathyroidism
-Increased uric acid, crystallization, not X-ray opaque --> hyperuricemia
Both kinds will show up on non-contract CT
193
Patient has managed hypertension means?
Patient is taking diuretics, beta blockers, ACE inhibitors, etc.
194
Protein-secreting cells of kidney? Where located?
alpha-intercolated cells of the distal nephron
195
genetic disease (rare) with defect in glycosyl phosphatydylinositol and/or protein? Sx? Signs?
"paroxysmal nocturnal hemoglobinuria
- cola colred urine in morning due to intravascular hemolysis
- take iron and folate supplements for anemia
- might see episodic DVT --> Warfarin
196
horseshoe kidney increases risk of? Trapped on? Cancer association?
Increased risk of obstruction, infection, stones - otherwise asymptomatic
Trapped by the inferior mesenteric artery
No cancer association unless patient has Turner's Syndrome, then there may be associated with Wilms Tumor
197
Mechanism of lithium toxicity in nephrogenic DI?
Acts as an ADH antagonist in collecting tubule
198
Haloperidol MoA?
Blocks dopamine at D2 receptors
199
Name 4 typical antipsychotics?
haloperidol, thioridazine, chlorpromazine, fluphenazine
200
Name an agent and MoA to relieve EPS? Unlikely alternative?
Benztropine --> blocks ACh receptors
| Can also use 1st gen antihistamine, it's antimuscarinic
201
Atypical antipsychotic lab values for hormones? Why?
Increased prolactin
Decreased GnRH, LH, and FSH
Meds block serotonin and dopamine; dopamine is the tonic inhibitor of prolactin --> block dopamine means increased prolactin, which inhibits the others
202
Medication and MoA in breast cancer tx?
Paclitaxel (taxanes); inhibit mitosis via microtubule stabilization
203
Most common location for diverticulosis?
Sigmoid colon -- painless rectal bleeding
204
Smell of bitter almonds on breath?
Cyanide poisoning, intentional or smoke inhalation; Disrupts cellular respiration
205
Common delusion in psych?
persecution; marriage to celebrity
206
Triceps innervation?
Radial nerve from C7-C8
207
C5-C6 damage?
Erb-Duchenne Palsy (waiter's tip) --> teres minor not working
208
mechanism of renal failure in HUS? Two other sx of HUS?
formation of microthrombi --> ischemia
| Also see anemia, thrombocytopenia
209
lab test to distinguish E. coli O157:H7?
Does not ferment sorbitol, only lactose (MacConkey agar)
210
Three vibrio species? Source of contamination?
Cholera, parahaemolyticus, vulniticus;
| From contaminated drinking water, seafood
211
Rapid onset illness, rapid off in food poisoning? Why?
B. cereus and S. aureus - both have preformed toxins
212
Competitive antagonist of the benzo binding site on gamma-amino butyric acid receptor? Use? Not effective for?
Flumazenil - reverse benzo overdose (not useful against barbiturates)
213
pharmacologic agent to treat carcinoid tumor? Symptoms? Also treats? Pathphys of carcinoid tumor? Diagnostic marker?
Octreotide. Symptoms are recurrent diarrhea, cutaneous flushing ,asthmatic wheezing, right-sided valvular disorder.
Also treats acromegaly, insulinoma, diarrhea from VIPomas
Pathophys is oversecretion of serotonin, will see increased 5-hydroxyindoleacetic acid (5-HIAA) in urine
214
symptoms of amiodarone toxicity?
weight loss, hyperreflexia, chest palpitation (eventually see cloudy vision, pulmonary fibrosis)
215
actute migraine relief medication? MoA?
sumatriptan - serotonin analog at 5-HT1b and 5-HT1d receptors on cranial arteries and veins and cranial/basilar artery --> vasoconstricution, relief; also treats trigeminal neuralgia
216
Effective medication for cluster HA?
subcutaneous sumatriptan, 96% effective in 15 minutes
217
organophosphate poisoning MoA? Treatment? MoA of treatment?
Organophosphates are cholinesterase inhibitors via covalent binding --> increased ACh in synapse, permanently on parasympathetic nervous stimulation (causes sx)
Reverse with atropine --> muscarinc receptor antagonist
Reverse with pralidoxime --> reverse nicotinic effects at skeletal muscle
218
Normal WBC numbers?
4,500 - 10,000 cells/uL
219
normal neutrophil numbers?
220
normal platelet numbers?
150,000 - 450,000 per dL
221
male RBC count? female RBC count?
4.7-6.1 x 10^6/uL; 4.2-5.4 x 10^6/uL
222
IV drug abuse and decreased WBC?
suspect HIV/AIDS and associated illnesses
223
Depression treatment with "safe" cardiac profile? MoA?
Phenelzine - monoamine oxidase inhibitor
224
Digoxin used in cardiac condition?
Positive inotrope treating CHF
225
What are the 3 G proteins? What does each do?
Gs, Gi, Gq;
Gs --> stimulate adenylyl cyclase --> increased cAMP --> increase Protein Kinase A activity
Gi -->L inhibit adenylyl cyclase --> decreased cAMP --> decrease Protein Kinase A activity
Gq --> activate phospholipase C --> PIP2 to IP3 and DAG --> release Ca++ --> activate Protein Kinase C
226
G-protein linked receptors?
alpha 1, alpha 2, beta 1, beta 2, M1, M2, M3, D1, D2, H1, H2, V1, V2, and then more that show up on board exams
227
pain in large joints with use, or as the day progresses? Small joint manifestation?
Osteoarthritis; See Heberden's nodes due to osteophytes
228
Horse shoe kidney implies increased risk of?
Wilms Tumor (may follow Turner Syndrome 45, XO
229
What does a Zenker diverticulum look like on barium swallow? Pathophysiology?
The barium shows up black - the esophagus will be a shorter or longer worm running down the neck, while the diverticulum will look like a big tongue (both are black due to the barium opacity); Abnormal spasm or diminished relaxation of the cricopharyngeal muscles during swallowing (cricopharyngeal motor dysfunction) is thought to be the underlying mechanism of Zenker diverticulum formation
230
Clinical manisfestation of Zenker diverticulum? Sequelae?
Trouble swallowing, foul breath due to retained food and bacteria in the diverticulum; Pulmonary aspiration of diverticular contents may lead to recurrent pneumonia
231
Distinguish when to use the two-sample z test or two-sample t test from chi-square analysis?
The two sample tests are used to compare 2 group means, not categorical variables. The chi-square test for independence is used to test the association between 2 categorical variables (not mean values of a single variable).
232
Major immune mechanism against Giardia? Deficiency causing recurrent infection?
CD4+ T helper cells and secretory IgA production mediate immune response to G. lamblia. Secretory IgA helps prevent and clear infection by binding to trophozoites and impairing their adherence to the upper small-bowel mucosa. Children with IgA deficiency, X-linked agammaglobulinemia and CVID have a predisposition to developing chronic giardiasis
233
Where do you find eosinophils fighting infection?
Important for combating intestinal helminths
234
Patient expresses worries about multiple daily issues, interferes with function? Treatment? Don't use?
Generalized Anxiety Disorder - treat with psychotherapy and SSRI like citalopram or SNRI. These meds also treat depression, a co-morbid condition. Benzodiazepines are second line therapy due to risk of tolerance and dependence, potential for rebound and withdrawal syndromes with abrupt discontinuation, should only be used acutely while other meds kick in.
235
Blood smear shows lots of unimpressive RBCs and maybe a funny shaped WBC? Typical condition? Associated malignant conditions?
That's a reactive lymphocyte - typical in mononucleosis. EBV associated with Burkitt Lymphoma, nasopharyngeal carcinoma, oral hairy leukoplakia (immunocompromised individual)
236
Organism that can produce insoluble dextrans from sucrose?
Strep viridans
237
Name some P450 inhibitors?
```
VICK's FACE All Over GQ STOPS ladies in their tracks:
Valproate
Isoniazid
Cimetidine
Ketoconazole
Sulfonamides
Fluconazole
Alcohol (acute)
Chloramphenicol
Erythromycin (macrolides EXCEPT acithromycin)
Amiodarone
Omeprazole
Grapefruit juice
Quinidine
```
238
Name some P450 inducers?
```
Bull Shit CRAP GPS INDUCES my rage:
Barbiturates
St. John's Wort
Carbamazepine
Rifampin
Alcohol (chronic)
Phenytoin
Griseofulvin
Phenobarbital
Sulfonylureas
```
239
GI bleed/hepatic encephalopathy connection? Treatment?
Yes, alcoholic with cirrhosis, but also the GI bleeding causes increased nitrogen delivery to the gut in the form of hemoglobin, which is then converted into ammonia and absorbed into the bloodstream. Yes, go for lactulose, acidify colon, etc.
240
Localized deposition of amyloid in the cardiac atria? Incidence? May lead to?
This is misfolded natriuretic peptide (beta-pleated sheet formation). Incidence increases with age, > 90% prevalence by ninth decade. Senile cardiac amyloidosis increases risk of atrial fibrillation
241
Misfolded protein responsible for primary systemic amyloidosis? Lab finding?
Immune globulin light chains, especially gamma-light chains and their fragments. Seen in monoclonal B-cell proliferations, deposition seen in heart, skin, tongue, gi tract, kidney, peripheral nerves. Bence Jones proteins found in serum and urine.
242
Fenaldopam indication and MoA?
Fenaldopam is a short-acting, selective, peripheral dpoamine-1 receptor agonist with little to no effect on alpha- or beta-adrenergic receptors --> Renal vasodilation leads to increased renal perfusion, diuresis, and natriuresis, great for patients with acute kidney injury due to severe hypertension or hypertensive emergency
243
One weird trick for treating cyanide poisoning?
Nitrites induce F++ to Fe+++, which has a very high affinity for cyanide. This sequesters cyanide in the blood (at the expense of O2 delivery) so that it can't damage mitochondria by inhibiting cytochrome c oxidase.
244
Peripheral smear shows cross-shaped intraerythrocytic inclusions? Transmission? Common coinfection?
Babesiosis caused by babesia, transmitted by Ixodes tick. Coinfection with Berrelia burgdorferi (Lyme disease) is common due to vector and geographic overlap.
245
Mechanism of autoregulation in coronary arteries?
Adenosine and nitric oxide. Adenosine, a product of ATP metabolism, acts as a vasodilatory element in the small coronary arterioles (so increased ATP use --> higher adenosine concentration --> autoregulatory vasodilation). Nitric oxide is released in reponse to pulsatile stretch and flow shear stress in the coronary arteries (more work, more NO --> vasodilation). NO is the major regulator of low-mediated vasodilation in large arteries and pre-arteriolar vessels.
246
Patient says face feels "funny", examination shows asymmetry of smile, effacement of the nasolabial fold. If not a stroke, what's going on? What else might be found on exam?
Presentation consistent with Bell's Palsy, an idiopathic paresis of the facial nerve. Facial nerve powers:
1) motor output to the facial muscles (obvious signs)
2) Parasympathetic innervation to lacrimal, submandibular, and sublingual salivary glands (decreased tears unilaterally, might be harder to see the saliva effect)
3) Afferent fibers for taste from anterior 2/3 of tongue
4) Somatic afferents from pinna and external auditory canal
247
Pressure tracing of the aorta lacks a little uptick hump? Auscultation finding?
Aortic regurgitation, the little uptick (dicrotic notch) in pressure occurs when the valve closes. Ineffective closure means the pressure falls evenly. Flow murmur will be greatest at the point where the aortic valve closes, as this represents the greatest pressure gradient across the valve.
248
Difference in lining of a true cyst versus a pseudocyst?
True cysts are lined by epithelial cells, pseudocysts are lined by fibrous and granulation tissue.
249
Common complication of pancreatitis that shows up as a big black space inside the pancreas on CT?
Pseudocyst - collection of fluid rich in enzymes and inflammatory debris.
250
Patient on statin not tolerating medication well. Alternative is started that inhibits cholesterol absorption at the brush border. What is it? SE?
Ezetimibe - inhibition of cholesterol transporter on intestinal enterocytes, decreased cholesterol uptake leads to liver compensation of increased LDL receptor expression, pulls cholesterol out of circulation. SE include increased LFT, diarrhea
251
Treatment of choice for organisms espressing extended-spectrum beta-lactamse? Where did they get the EBSL gene?
Go for carbapenems (imipenem) to treat EBSL-producing organisms. The genetic information for encoding EBSL is shared among bacteria via conjugation-shared plasmids.
252
Chloride content of erythrocytes in venous versus arterial blood? Enzyme associated with this shift?
Low in arterial blood, high in venous blood. Carbonic anhydrase, the chloride is balancing bicarbonate produced from CO2. Carbonic anhydrase converts CO2 to carbonic acid (H2CO3), which equilibrates with bicarb (HCO3-). The bicarb diffuses out of the RBC, Cl- diffuses in to maintain charge balance. This is the chloride shift.
253
Topical vitamin D analogs treat? How? Name one?
Can treat psoriasis - medication binds to and activates the vitamin D receptor, a nuclear transcription factor that causes inhibition of keratinocyte proliferation and stimulation of keratinocyte differentiation. Also inhibits T cell proliferation and other inflammatory mediators. Calcipotriene (and prolly others with some relationship to "calcium" in the name)
254
monoclonal antibody that can be used to treat psoriasis?
Ustekinumab is a human monoclonal antibody used in psoriasis that targets IL-12 and IL-23, inhibiting differentation and activation of CD4+ T helper cells.
255
Rectal administration of a drug?
Bypasses hepatic metabolism, as 2/3 of rectal drainage (middle and inferior rectal veins) go to systemic circulation via internal iliac.
256
Cervical and/or axillary lymphadenopathy, fever/sore throat, and peripheral blood smear shows irregularly shaped WBC?
The irregular WBC is a reactive lymphocyte (a CD8+ T cell, also called Downey Cells, though not very often), characteristic of infection with EBV.
257
Patient with sore throat and exudate is treated with amoxicillin. Returns with rash, what's going on? Really important distinction?
The patient probably has mono, not strep, the amoxicillin causes a maculopapular rash (and the doesn't treat EBV). This reaction is not an allergic reaction to a penicillin-type drug, mechanism of rash not well-understood.
258
Currant jelly stool?
Meckel diverticulum, painless bleed, Rule of 2s. Doubt this code word will be on step exam
259
Side effects of statin therapy? Must pre-test?
SE include myopathy and hepatitis. LFT recommended before starting therapy
260
What amino acid becomes essential in a patient with phenylketonuria (PKU)? If not supplemented?
Tyrosine - PKU patients follow diet without phenylalanine, a precursor for tyrosine. Without tyrosine supplementation, see drop in DOPA and other catecholamines.
261
Early virilization in a male (i.e., 4 year-old needs deodorant, is hangin'). Serum test?
21-hydroxylase deficiency - may or may not be salt wasting, if older presentation, then not salt-wasting (tricky!). Should see congenital adrenal hyperplasia, increased androgens (source of virility in males, ambiguous genitalia in females). Check for elevated levels of 17-hydroxyprogesterone levels (and androgens).
262
In someone with virilization, how do you know it's 21-hydroxylase deficiency and not androgen overproduction due to pituitary adenoma pumping out ACTH?
Excess ACTH would indeed result in excessive adrenal androgen production, but the symptoms of excess cortisol production (i.e., Cushing's syndrome) would dominate.
263
What is the missing feedback mechanism in 21-hydroxylase deficiency that triggers excess ACTH secretion? Treatment?
No cortisol - cortisol feeds back to the hypothalamus to suppress ACTH release. Treat by supplementing with low-dose exogenous corticosteroids to suppress ACTH secretion --> decrease excess androgen production by adrenal cortex.
264
Adverse effect of O2 therapy in a neonate with RDS?
Retinal damage - temporary local hyperoxia in the retina is thought to induce changes that cause up-regulation of proangiogenic factors such as VEGF upon return to room air, leading to neovascularization and possible retinal detachment or blindness.
265
Recombination versus reassortment in a virus?
Recombination means exchange of genetic material through crossing-over event. Reassortment means exchanging genetic material by swapping units, such as the segments in different strains of influenza or rotavirus
266
Animal host implicated in reassortment of influenza viral strains?
Pig
267
Downstream effect of phenotypic mixing of viruses?
In phenotypic mixing, virus coinfection in the same cell can lead to packaging a new virus with intact genome from one virus and nucleocapsid or envelope material of the other. The new virus is infective, and maybe has novel properties, but the genome is unchanged - subsequent progeny revert to the normal phenotype.
268
Aneurysm of this artery laterally impinges on the optic chiasm? Visual field defect?
Internal carotid - causes ipsilateral nasal hemianopia by damaging uncrossed optic erve fibers from the temporal portion of the retina.
269
You have some measurement for renal blood flow. What's the renal plasma flow? What's the next calculation you might want?
Multiply by 1 minus the hematocrit, i.e., RPF = RBF x (1 - hematocrit). Once you have RPF, this can be combined with GFR and FF via relationship FF = GFR/RPF, useful when looking at urine and serum values of some freely-filtered blood component.
270
Serum marker for hepatocellular carcinoma? Also a marker for?
Alpha fetoprotein - also germ cell tumors
271
Serum marker for pancreatic tumor?
CA 19-9
272
Elevated 5-hydroxyindoleacetic acid in the serum or urine?
Major breakdown product of serotonin, elevated levels in urine indicate carcinoid and certain neuroendocrine tumors
273
Craniopharyngeoma embryology tie in? Tricky distinction?
Tumor of a remnant of Rathke's pouch. The anterior pituitary is formed from an out-pouching of the pharyngeal roof and is called Rathke's pouch. The posterior pituitary gland arises from an extension of the hypothalamic neurons, not embryologically related.
274
Red-flags for drug-seeking behavior (3)? Early step in management?
1) Asking for medication by name
2) running out of medication (maybe even "lost" or "stolen")
3) pain out of proportion to physical exam
After making sure patient is stable and not about to keel over in the ER, obtain confirmation of prescription history through prescription drug monitoring program or similar.
275
lipoxogenase inhibitor? Indication?
zileuton - direct inhibition of LOX --> decreased leukotrienes, treat asthma
276
Leukotriene that calls in inflammatory cells for asthma attack
LTB4 - chemoattractant for neutrophils, etc.
