USMLE Rx: Week 06/13/16 Flashcards
By which route is cyclosporine metabolized?
Hepatic
Review the mechanism of cyclosporine.
Cyclosporine binds to cyclophilin and they together inhibit calcineurin. Calcineurin is a phosphatase that removes phosphate groups from NF-AT, thus activating it.
Clostridium difficile risk increases with __________.
antibiotic use
What two antibiotics kill Clostridium difficile?
Metronidazole and vancomycin
Cyclosporine can cause ________-toxicity.
nephro
Rheumatic fever can be caused by Streptococcus pyogenes (group A Strep.). What are the JoNES criteria that signify rheumatic fever?
Joint pain Nodules (collagenous deposits on the wrists) Erythema marginatum (rash that starts on the trunk and moves outward) Syndenham chorea (sudden jerky movements)
Treat symptomatic atrial fibrillation with _________.
Beta-blockers
Sarcoidosis, multiple myeloma, hemochromatosis, and radiation therapy all lead to what kind of cardiac complication?
Restrictive heart failure
Epstein-Barr virus is a ______-virus.
herpes
Tamponade leads to what ECG finding?
Alteration of QRS height with each beat
Sarcoidosis can lead to what elevated lab finding?
Hypercalcemia
Other than macrophages, what type of leukocytes are involved in the granulomas of sarcoidosis?
CD4
Sarcoidosis can cause hypercalcemia without high levels of ______________.
parathyroid hormone, because the extra macrophages in those with sarcoidosis convert vitamin D to its active form, thus increasing calcium absorption
Under normal circumstances, oxygen is a _______-limited gas. Exercising increases this, thus making oxygen more like carbon monoxide.
perfusion (thus, upon exercising oxygen becomes more like CO)
G-CSF binds to which cell receptor?
CD34
An opening snap, followed by a late rumbling diastolic murmur is characteristic of ___________.
mitral stenosis
Which type of anemia can present with neurologic symptoms?
B12 deficiency (not folate deficiency)
What inheritance pattern does hereditary spherocytosis display?
Autosomal dominant
Increased mean corpuscular hemoglobin concentration indicates which type of hematologic abnormality?
Hereditary spherocytosis
Where in the vascular circuit will the concentration of T hemoglobin be highest?
The peripheral capillaries, because the T form is the deoxy state
Which will patients with renal-artery stenosis have, hypernatremia or hypokalemia?
Hypokalemia, because hypernatremia usually results from decreased water intake, whereas hypokalemia results from high-aldosterone states
What do anti-Smith antibodies target?
snRNA
The presence of anti-nuclear antibodies is highly ________ for SLE.
sensitive, but not specific; almost 100% of people with lupus have this, but some have it and do not have SLE
How do beta-blockers affect stroke volume and mean arterial pressure?
They decrease both; although beta-blockers allow for more filling time, the negative inotropic effects overall decrease stroke volume.
CYP interactions typically only present while the drug is ____________.
in the system; as such, if a patient stops taking a CYP-affecting drug, then the interactions should stop
When do children usually potty train?
Age 3
What is the presentation of Plummer-Vinson syndrome?
Glossitis
Dysphagia
Iron-deficiency anemia
Esophageal web
Microcytic, hypochromic anemia is usually ___________.
iron-deficiency
Other than aneurysms, to what are people with Ehlers-Danlos susceptible?
Scoliosis
Retinal detachment
How will sepsis affect cardiac output, systemic vascular resistance, and pulmonary capillary wedge pressure?
CO: increased (in response to decreased tissue perfusion)
SVR: decreased (because of the cytokines released)
PCWP: decreased (because of the increased permeability of the pulmonary vasculature)
There are four trinucleotide-repeat disorders. What are they, and what mnemonic is helpful in remembering them?
Try Hunting for My Fried X Huntington's Myotonic dystrophy Friedrich ataxia Fragile X
What is dysarthria?
difficult or unclear articulation of speech that is otherwise linguistically normal
On what chromosome is Friedrich ataxia found? What protein does that gene encode?
Chromosome 9 (like Friedrich Nietzsche in the 18nine0s) Frataxin
List some of the presenting signs of Friedrich ataxia?
Ataxia
Scoliosis
Dysarthria
Hypertorphic cardiomyopathy
Other than treating acetaminophen overdose, what does N-acetylcysteine do?
It loosens mucus, and thus is used to treat cystic fibrosis.
Although hereditary spherocytosis leads to an increased reticulocyte count, it is considered a ______-cytic anemia.
normocytic
G6PD deficiency is passed on in a _________ pattern.
X-linked recessive
In RBCs, the only source of glutathione is ____________.
G6PD
The chief symptom of G6PD deficiency is ___________.
hemolytic anemia after oxidative stress
If you have high sensitivity, then you have few _______.
false negatives
If you have low specificity, then you have lots of ___________.
false positives
Vitamin D undergoes two hydroxylations: first in the _______, then in the ________.
liver; kidney (under the influence of parathyroid hormone)
Vitamin D deficiency will lead to low levels of ____________ and high levels of __________.
phosphate and calcium; parathyroid hormone
Calcium absorption in the distal tubule is controlled by _____________.
parathyroid hormone
Type III collagen is necessary for ___________.
vascular synthesis
There are two types of Ehlers-Danlos syndrome: _______________.
classical (type V collagen; hypermobility) and vascular (type III; no joint-hypermobility)
Describe Fanconi anemia.
An inherited aplastic anemia resulting from DNA repair defects; leads to short stature, bifid thumbs, and cognitive impairment
If a patient has been receiving broad-spectrum antibiotics, which coagulation factors could be deficient?
All of the vitamin K-dependent ones, because vitamin K participates in enterohepatic recirculation – which is aided by bacteria; as such, factors II, VII, IX, and X could be low
High altitude stimulates ______________ 2,3-BPG.
production of (which then lowers the oxygen affinity of hemoglobin by stabilizing the deoxygenated state)
Of Sjögren and Sjögren-Larsson syndrome, which is autoimmune?
Sjögren syndrome (SL is a disorder of fatty-acid metabolism)
On what chromosomes are the genes for ADPKD and ARPKD?
ARPKD = 6
ADPKD = 16
(Think, both have a six, and the one that presents at a younger age is smaller.)
Which arteries communicate between the radial and ulnar branches in the hand?
The deep and superficial palmar arch
Sometimes fetuses are born with only one _____________; it is a nonspecific finding that can be associated with other congenital abnormalities.
umbilical artery (as opposed to the normal two)
Kidneys participate in gluconeogenesis. What is the rate-limiting enzyme there?
Fructose-1,6-bisphosphatase
Describe Gilbert syndrome.
Gilbert syndrome results from a defect in the promoter region of the gene for uridine glucuronyl transferase; without this, bilirubin cannot be conjugated and icterus can result from fasting
Ankylosing spondylitis and ulcerative colitis both have associations with what HLA?
B27
From what aortic arch does the dutus arteriosus arise?
The sixth (think… having six in public [PDA] is not ok)
Which platelet receptor normally binds fibrinogen? What drug targets this receptor?
GP IIb/IIIa
Abciximab
Mnemonic: think of Abbie with a six pack (abcix-) reciting “to be, or not three a” and fibbing about reading poems at Carnegie Hall
What do the Plavix drugs (-dogrel) target?
ADP receptor
What does a PF-4 positive result indicate?
That antibodies have been made to heparin and platelets (heparin-induced thrombocytopenia)
Mnemonic: PF = “platelets falling”
LMWH decreases __________.
factor Xa
Describe the presentation and pathophysiology of Liddle syndrome.
AD disorder
Constitutive expression of aldosterone-inducible ENaC channels (on the principal cells)
Leads to hypertension, low renin, and low aldosterone
Treat with triamterene or amiloride
What enzyme is defective in Pompe disease?
Alpha-1,4-glucosidase; absence of this leads to glycogen deposition on the heart
What is given with isoniazid?
Pyridoxine (vitamin B6), because isoniazid causes vitamin B6 deficiency
All of the anesthetics ending in __________ can cause malignant hyperthermia.
-flurane
What are two worrisome complications of malignant hyperthermia?
Rhabdomyolysis and arrhythmias
What is a dromotropic effect?
Speed through the AV node
What cardiac problem can some anesthetics cause?
The -icaine anesthetics block sodium channels and can cause AV heart block
