RX Questions Flashcards
Digoxin mechanism
Digoxin works by inhibiting the Na+/K+ ATPase pump, and causes direct increase of Na+ in the cell. This increase inhibits the activity of the Na+/Ca+2 pump which then increases Ca+2. Ca+2 increase causes an increase in contractility
Toxicity can result in hyperkalemia
Adenosine and AV nodal arrhythmia
Adenosine will abolish AV nodal arrhythmia => Narrow QRS suggests that an electrical signal originates above the ventricles. Also, p-wave obscured by the t-wave.
Adenosine mechanism => Hyperpolarizes AV nodal tissue by increasing potassium conductance and reducing calcium, and it has a very short duration of action
Aortic arch embryology
First arch = maxillary artery
Second arch = Stapedial and hyoidal arteries (only in developing embryo)
Third arch = Common carotid and proximal internal carotid arteries
Fourth arch = Ascending arch of the aorta on the left and proximal right subclavian artery on the right
Fifth arch = Regresses (no arteries)
Sixth arch = Proximal pulmonary arteries and ductus arteriosus
STEMI of the RCA
ECG elevation in II, III, and aVF (inferior leads) => inferior segment of the heart
STEMI of the LAD
ECG elevation in V3, V4 (anterior leads) with ST depression in II, III, and avF.
Symptoms of Congestive Heart Failure (CHF)
Dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, peripheral edema with weight gain. Sudden cardiac death or cardiac arrhythmia
Class I antiarrhythmics
Use Dependent block of Na+ channels in the open/inactivated state (they affect tissue that is more frequently depolarized)
All class 1 drugs decrease the slope of phase 0 of the cardiac action potential.
Tearing chest pain is commonly associated with what cardiovascular complication?
Aortic dissection => ascending dissection can cause pericardial tamponade, mediastinal hemorrhage. Descending can cause acute renal failure due to block of the renal artery.
Beck triad of cardiac tamponade
Jugular venous distention, hypotension, and muffled heart sounds.
Also, pulsus paradoxus is typical. (an abnormally large decrease in stroke volume, systolic blood pressure and pulse wave amplitude during inspiration)
Treatment of cardiac tamponade
Pericadiocentesis allows to immediately decompress the pericardial sac
Coarctation of the aorta and blood pressure
Upper extremity blood pressure will be greater than lower extremity blood pressure.
Coarctation of the aorta happens in 3-10% of Turner Syndrome patients
Wolff-Parkinson White syndrome ECG findings
Wide QRS with short PR intervals and slurring of the initial QRS complexes
WPW is due to an accessory conduction pathway that causes pre-excitation of the ventricle. Slurred upstroke of the QRS complex is called a delta wave.
How does carotid sinus massage alleviate SVT?
Baroreceptors in the carotid sinus respond to arterial wall stretching and massage causes these receptors to fire and thus leads to a decreased heart rate via increased parasympathetic activity
Hodgkin lymphoma common treatment regimen
ABVD
Adriamycin (doxorubicin)
Bleomycin
Vinblastine
Dacarbazine
Side effect of doxorubicin therapy
Cardiomyopathy commonly occurs with doxorubicin therapy
What is the cardinal vital sign for a pulmonary embolism?
Tachycardia
Also:
Tachypnea and pain on inspiration
Bleomycin mechanism of action and select side effects
Bleomycin is a mixture of glycopeptides that produce superoxide and hydroxyl radicals that attack DNA bonds to cause fragmentation.
Side effects include pulmonary toxicity and fibrosis, as well as skin changes and alopecia
Mesonephric (Wolffian) duct development in males
The Wolffian ducts develop into most of the male internal genital structures in response to Testosterone. These structures are BEEDS: Bladder Epididymis Ejaculatory duct Ductus deferens Seminal vesicles
The penis, scrotum, and prostate develop under the influence of DHT and are NOT derived from the mesonephric ducts.
Molar pregnancy
Non-viable fertilized egg that implants into the uterus. It is caused by a single sperm (90%) or two sperms (10%) combining with an egg that has lost its DNA.
Ultrasound appearance will show “snowstorm” with lucent and echogenic areas.
There will be markedly elevated B-hCG, and the classic TRIAD of symptoms includes hyperemesis, vaginal bleeding, and hyperthyroidism.
Hyperthyroidism is likely secondary to the homology of the alpha subunit of the B-hCG protein with the TSH protein.
What nerve is typically injured when a patient presents with wrist drop?
Radial nerve => innervates the posterior compartments of the arm and forearm, and allows for extension of the wrist.
It also innervates the posterior cutaneous hand except for the distal digits and the last one and a half fingers.
Importantly, the radial nerve is not affected in carpal tunnel syndrome because it does not pass through the carpal tunnel.
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What types of tumors are Psammoma bodies typically found in?
PSaMMomA: https://i2.wp.com/
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Papillary carcinoma of the thyroid Serous (ovary) Meningioma Mesothelioma Appendiceal carcinoid
Parvovirus B19 infection physical exam findings
Slapped cheek appearance = Erythema of the cheeks = IgG antibody formation to the virus.
Commonly also see anemia, and is particularly dangerous to the fetus of a pregnant woman.
HIV protease inhibitor side effects (-vir drugs)
GI intolerance, lipodystrophy, lipoatrophy peripherally and accumulation of fat within the abdomen, breasts, and cervical vertebrae (cervicodorsal fat pad). Hyperlipidemia is also common.
(Think of similar appearance of corticosteroid treatment)
Methotrexate mechanism of action and side effects
Methotrexate impairs DNA synthesis through its action at the dihydrofolate reductase inhibitor. It blocks folic acid production in healthy and cancerous cells alike and kills both.
Leucovirin can “rescue” normal cells by displacing methotrexate and enabling folic acid production to continue for DNA synthesis to resume
What is paroxysmal nocturnal hemoglobinuria (PNH)?
PNH is a rare form of hemolytic anemia that commonly presents with changes in urine color in the morning.
Signs and symptoms include normocytic anemia, elevated unconjugated bilirubin, elevated lactate dehydrogenase, and low haptoglobin.
TRIAD - hemolytic anemia, pancytopenia, thrombosis.
Defect: A defective protein known as glycosylphosphatidylinositol (GPI) (PIG-A gene) anchor is present on the RBC membrane. Normally, this protein attaches to the surface of RBCs to prevent the attachment of complement. However, in this condition, complement attaches and causes RBC lysis. Flow cytometry will show CD55/59 negative RBCs.
Treatment is with ECULIZUMAB, a terminal complement inhibitor.
What is the mechanism of action of nitroglycerin?
Nitroglycerin causes production of the metabolite NO. NO then potently activates guanylyl cyclase, and thus increases cGMP levels in the cell to serve as a substrate to stimulate dephosphorylation of myosin, thus causing arterial and venous dilation.
Mechanism of action of fibrates
Fibrates act via stimulation of peroxisome proliferator-activated receptors (PPAR-a) and acts as a transcription factor to increase HDL levels by inducing apoA-1 and apo-AII, as well as increasing lipoprotein lipase lipolysis to rapidly turnover VLDL and triglycerides
Mechanism of action of cholestyramine
Cholestyramine is a bile acid-binding resin that binds negatively charged bile acids and bile salts in the small intestine and excretes them in the feces, thus decreasing cholesterol concentration absorbed in food. Decreased absorption activates the liver to take up LDL particles and thus decreases total plasma LDL levels.
Where do the major vessels of the abdomen pass through?
The IVC is the only structure that directly passes through the central tendon of the diaphragm muscle. The IVC traverses the diaphragm at the T8 level. One can remember this with the mnemonic “I 8 10 EGGs AAT 12”:I 8=IVC at T8;10 EGGs =EsophaGus and vaGus at T10; andAAT 12=Aorta,Azygos, andThoracic duct at T12.
Crigler-Najjar syndrome type I
unconjugated hyperbilirubinemia that is usually fatal within 18 months of life secondary to kernicterus; Multiple genetic defects in the gene for bilirubin uridine diphosphate-glucuronosyltransferase (UGT1) that completely abrogate activity can give rise to this disorder.
What is a hapten?
On its own, ahapten molecule cannot elicit an immune response, as it cannot activate helper T cells.However, when a hapten molecule binds to a protein, the hapten-protein conjugate is capable of eliciting an immune response
Carcinoid tumors
Secrete serotonin, which causes flushing, watery diarrhea, and right-sided valvular heart failure. 5-HIAA is detected in urine.
Treatment involves surgical resection and somatostatin analog (octreotide)
Kawasaki Disease
Small to medium vessel vasculitis that presents in children <4 years old of Asian descent. Signs include fever, conjunctivitis, mucositis, vesicles or ulcers of the lips and oral mucosa, and lymphadenitis. Coronary aneurysms are the worst complication. Treatment includes ASA and IVIg.
Therapy for prinzmetal angina
Prinszmetal angina is characterized by chest pain at rest, often in a young patient with a history of vasospastic disease such as Raynaud or migraines. Treatment is abortive with NTG, or reduced frequency of episodes with calcium channel blockers.
Sulfa derivative diuretics
Acetazolamide, furosemide, HCTZ are all sulfa drugs
Key pathologic finding in hypertrophic obstructive cardiomyopathy (HOCM)
Hypertrophy with asymmetric SEPTAL enlargement without free ventricular wall enlargement. Disease is AD and caused by sarcomeric gene mutation, such as B-myosin heavy chain.
Physical exam findings in HOCM
Dynamic ventricular outflow obstruction during systolic ejection leads to a systolic murmur, dyspnea, lightheadedness, syncope and sudden cardiac death secondary to V-Tach
IVC Compression in pregnancy
IVC compression is common in women during the third trimester of pregnancy when the uterus compresses the IVC and decreases venous return to the heart. This reduces cardiac output, and thus pregnant women should light on their left side or place a pillow under their right hip to remove the uterine weight from the IVC.
Types of Hypersensitivity reactions
Type I - Histamine, allergic reaction - Allergic Anaphylaxis and Atopic Dermatitis
Type II -AntiBody Dependent cytotoxicity
Type III - Immune Complex aggregations of Ag-Ab (PSGN, Lupus, Rheumatoid Arthritis)
Type IV - T-Cell mediated Delayed hypersensitivity