Shared Flashcard Set

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USMLE Step 1
Jenna's QBank
60
Medical
Graduate
02/07/2006

Additional Medical Flashcards

 


 

Cards

Term
Which species of bacteria have AB toxins?
Definition
Vibrio cholera and Bacillus cereus (AB5) Corynebacterium diptheriae (AB)
Term
What are three anti-cholingergics that penetrate the blood-brain barrier?
Definition
Pilocarpine, physostigmine, and parathion
Term
Name several cholinomimetics (meaning drugs that act as muscarinic agonists). What is unique about these drugs?
Definition
Bethanechol
Carbachol
Pilocarpine
Methacholine

They are unique because they are not degraded by acetylcholine esterase
Term
Name several cholinesterase inhibitors.
Definition
Tacrine (similar to donepezil, rivastigmine, and galanthamine)
Parathion (and other organophosphates)
Edrophonium
Pyridostigmine
Physostigmine
Neostigmine
Term
Name two muscarinic antagonists. Which is used more systemically?
Definition
Atropine and Ipratroprium. Atropine used more systemically, whereas Ipratroprium is used mainly as an M3 antagonist in the treatment of asthma and COPD to decrease respiratory secretion and decrease bronchoconstriction.
Term
What is the only Gram positive bacterium with endotoxin? What does this bacterium have in common with Streptococci? How will you tell them apart.
Definition
Listeria monocytogenes has endotoxin. It is also beta-hemolytic, similar to Streptococci. You will distinguish them with catalase testing, as L. monocytogenes is catalase positive, whereas all Streptococci are catalse negative.
Term
What is the only Gram negative bacterium without typical endotoxin?
Definition
Bacteroides
Term
What would be some containdications to the use of Bethanechol?
Definition
Bethanechol is a systemic muscarinic agonist, so contraindications would be asthma (due to increased bronchoconstriction and bronchosecretions), AV nodal heart block (muscarinic agonist will slow AV nodal conduction), heart failure (due to decreased myocardial contractility with muscarinic agonist).
Term
What is the difference between wide and narrow angle glaucoma?
Definition
Narrow angle glaucoma occurs when the iris partially blocks the trabecular meshwork of the eye, preventing drainage of aqueous humor. Wide angle glaucoma occurs when you just have poor tone of the trabecular network, and this no physical impedement to aqueous humor outflow.
Term
What is the difference between Physostigmine and Pyridostigmine?
Definition
Physostigmine is used to treat glaucoma, and it crosses the BBB. Pyridostigmine is used in the treatment of myasthenia gravis.
Term
Describe the Tensilon Test.
Definition
Tensilon (Edrophonium) is an extremely short-acting inhibitor of acetylcholinesterase. It is used to distinguish cholinergic crisis (due to overmedication) from worsening symptoms (undermedication) in myasthenia gravis. Edrophonium will worsen a crisis, but improve symptoms of undermedication.
Term
What are the symptoms of organophosphate poisoning? How is it treated?
Definition
Diarrhea, loss of visual acuity due to ciliary body paralysis, increased secretions (tears, bronchosecretions, salivation, sweating), coma, seizures, respiratory depression, muscle twitching, weakness, flaccid paralysis. To treat the poisoning, you must administer a cholinesterase regenerator (Pralidoxime) before the organophosphates "age". Administer emetics, perform gastric lavage, give activated charcoal, administer atropine.
Term
You have just brought a patient out of the operating room. What will you administer as they are coming out of anesthesia, and why?
Definition
Neostigmine reverses non-depolarizing neuromuscular blockade, which will counteract the paralytic agent that was administered before surgery. Neostigmine will also help treat any possible neurogenic ileus or bladder that may result from surgery on the gut.
Term
Which species of Gram + bacilli are spore-formers?
Definition
Clostridia and Bacilli
Term
Which species of Gram + Bacilli are non-spore-formers?
Definition
Listeria and Corynebacterium
Term
How would one distinguish Bacilli from Clostridium?
Definition
Clostridium species are obligate anaerobes, whereas bacillus species are aerobes.
Term
How would one distinguish between the speces of Bacillus (Gram +, spore-forming, aerobic bacilli)?
Definition
B. cereus is motile, whereas B. anthracis is non-motile
Term
How would one distinguish between the species of Clostridium?
Definition
C. perfringens is the only non-motile one; all the others are motile.
Term
How would one distinguish between the non-spore-forming, Gram + bacilli (and they are...?)
Definition
Listeria monocytogenes and C. diphtheriae; Listeria is motile, whereas Corynebacterium is not.
Term
How do you tell Staph from Strep?
Definition
Catalse test (Staph are positive, Strep are negative)
Term
How would one distinguish between the Staphylococcus species?
Definition
S. aureus is the only coagulase + one; S. epidermidis and S. saprophyticus are coagulase negative. S. epidermidis is novobiocin sensitive, whereas S. saprophyticus is novobiocin resistant.
Term
What two Strep species are beta-hemolytic? How do you tell them apart?
Definition
S. pyogenes and S. agalactiae, and you tell them apart because S. pyogenes is bacitracin-sensitive, whereas S. agalactiae is bacitracin-resistant.
Term
What two Strep species are alpha-hemolytic? How do you tell them apart?
Definition
S. pneumoniae and Viridans Strep are both alpha-hemolytic, and you can distinguish them by using optochin. Viridans is optochin-resistant, whereas S. pneumoniae is optochin-sensitive. S. pneumo also has a capsule (and thus a positive Quellung reaction) whereas Virdians Group Strep are acapsular.
Term
Which Strep species are non-hemolytic or have mixed hemolysis?
Definition
S. bovis, Enterococcus Faecalis, and Peptostreptococcus.
Term
What is Peptostreptococcus?
Definition
An anaerobic Gram positive organism usually classified with Strep that has mixed or no (gamma) hemolysis and is commonly found in mixed infections.
Term
What are the virulence factors of S. aureus?
Definition
Protein A (binds Fc portion of IfG), coagulase (forms fibrin coat around the organism), hyaluronidase (breaks down host connective tissue), lipase (breaks down host fat)
Term
What are the disease-causing toxins of S. aureus?
Definition
TSST-1 (Toxic Shock Syndrome), Exfoliative toxins A and B (Scalded Skin Syndrome) and Enterotoxin (food poisoning)
Term
What underlying disease would one be concerned about if a patient tested positive for Strep bovis?
Definition
colon cancer (or less likely, inflammatory bowel disease)
Term
What are some pathologies caused by Viridans Streptococci?
Definition
Dental caries, brain or abdominal abscesses, and subacute bacterial endocarditis
Term
What are the clinical features that distinguish atypical pneumonia from typical pneumonia?
Definition
Typical pneumonia usually has rapid onset of fever, chills, productive cough with rusty-colored sputum, and a lobar presentation on CXR. Atypical pneumonia's onset is often more insidious, cough tends to be dry, CXR reveals fluffy, diffuse infiltrates.
Term
What are some of virulence factors of S. pneumo? What diseases does S. pneumo cause? What type of patients are especially susceptible to S. pneumo?
Definition
Antiphagocytic capsule and IgA proteases. S. pneumo causes otitis media, pneumonia, and meningitis, mostly all in adults. Asplenic patients are especially susceptible to S. pneumo.
Term
Which organisms that cause food poisoning have the most rapid onset?
Definition
S. aureus and B. cereus
Term
What kind of paralysis is associated with C. botulinum? What kind of paralysis is associated with C. tetani? What kind of a paralysis is associated with Guillan-Barre Syndrome?
Definition
Botulism=flaccid decending paralysis due to ACh release blockage. Tetanus=rigid paralysis due to inhibition of GABA release. Guillan-Barre=ascending flaccid paralysis.
Term
Which muscarinic agonists are metabolized by AChE? Which are not?
Definition
ACh and Methacholine are hydrolized by acetylcholinesterase. Pilocarpine and Bethanechol are not hydrolyzed.
Term
What are the 3 muscarinic receptor antagonists?
Definition
Atropine, Scopolamine, and Ipratroprium
Term
Where are the M1 muscarinic receptors? M2 muscarinic receptors? M3s?
Definition
M1s in the CNS, M2s in the cardiovascular system, and M3 is in the lung, GI tract, GU tract, and eye
Term
Where are nicotinic receptors?
Definition
First synapse sympathetic, first synapse parasympathetic, synapse on the adrenal medulla, synapse on the skeletal muscles
Term
What are the effects of nicotine?
Definition
Nicotine is a ganglionic stimulant at low doses and a ganglionic blocker at high doses, so it binds to nicotinic receptors at low doses and blocks sympathetic and parasympathetic output. Increased heart rate, increased BP, increased GI motility.
Term
What are three cholinergic synapses?
Definition
Second parasympathetic muscarinic synapse (plus sweat and salivary glands for sympathetic system); Neuromuscular junction nicotinic receptor; ganglionic nicotinic receptor for the first synapse of parasympathetic and sympathetic.
Term
What are the genera of Gram positive cocci?
Definition
Staphylococcus, Streptococcus, and Enterococcus
Term
Post-streptococcal acute glomerulonephritis and rheumatic fever are both complications of infection with S. pyogenes. What is the difference in the pathogenesis of these two diseases?
Definition
Post-streptococcal acute glomerulonephritis occurs when circulating immune complexes are deposited in the glomeruli, triggering an inflammatory reaction. Rheumatic fever occurs when the antibodies made against the S. pyogenes bacterial antigens cross react with heart valves and and joint tissue.
Term
What types of infections are caused by S. aureus?
Definition
impetigo, cellulitis, furuncle, carbuncle, pneumonia, acute endocarditis, osteomyelitis, septic arthritis, meningitis
Term
What is the difference between S. aureus and other Staphylococcal species?
Definition
S. aureus is coagulase + and it produces exotoxin. S. aureus colonies will be yellow, while the other Staph species will grow white colonies.
Term
How do S. epidermidis and S. saprophyticus differ? How are they similar?
Definition
S. epidermidis is novobiocin-sensitive, whereas S. saprophyticus is novobiocin-resistant. S. epidermidis may cause a variety of infections in the immunocompromised or recently surgerized person, whereas S. saprophyticus is known solely as a pathogen responsible for urinary tract infections.
Term
Which drug is used to treat status asthmaticus?
Definition
Terbutaline
Term
What drugs are used to treat preterm labor?
Definition
Ritodrine and terbutaline
Term
Why is it a bad idea to abruptly stop clonidine?
Definition
Because it may result in rebound hypertension
Term
Of the three Gram-negative respiratory pathogens, which is NOT spread person-to-person?
Definition
L. pneumophila
Term
What are the growth requirements of H. influenzae?
Definition
NAD and Heme
Term
What are some of the pathologic effects of B. pertussis?
Definition
Cilliary paralysis; inactivation of the Gi subunit of cAMP system, which promotes secretions; tracheal cytotoxicity
Term
What are the nutritional requirements for L. pneumophila to grow on culture?
Definition
Iron and cysteine
Term
What bacterial organisms produce IgA proteases?
Definition
H. influenzea, S. pneumoniae, N. meningitidis
Term
What is the important thing to know about the structural feature of Mycoplasma species?
Definition
NO CELL WALL: cholesterol-padded membranes
Term
What are the hallmarks of infection with Mycoplasma pneumoniae?
Definition
Streaky chest x-ray that looks worse than the person's presentation would suggest
Term
Name three bacterial species that can produce urethritis.
Definition
Ureaplasma urealyticum, N. gonorrheae, C. trachomatis
Term
Which infectious agents cause a rash on the palms and soles?
Definition
Coxsackie virus, Rocky Mountain Spotted Fever, Typhus (trunk rash first), syphilus
Term
Which infectious agents cause desquamation of palms and soles?
Definition
S. aureus (TSS), S. pyogenes (scarlet fever)
Term
What diseases present with migratory arthritis?
Definition
Colitic migratory arthritis, gonoccocal disease, Lyme Disease, Rheumatic Fever
Term
Name two obligate intracellular bacterial parasites.
Definition
Chlamydia and Rickettsia
Term
What are some causes of dilated cardiomyopathy?
Definition
Pregnancy, doxyrubicin, hypertension, alcohol abuse
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