Q Banks: Week of 03/20/17 Flashcards
What does opsoclonus-myoclonus syndrome likely portend in a young child?
Neuroblastoma
With a mean age of onset of 2 years, neuroblastoma is the most common extracranial tumor of childhood. It causes a disorder in which children can have non-rhythmic nystagmus with myoclonus.
True or false: tardive dyskinesia specifically refers to tongue movements.
False. Tardive dyskinesia refers to any purposeless repetitive movements such as writhing fingers or facial grimacing.
How is acute dystonia different from tardive dyskinesia?
Acute dystonia is sustained muscle contraction, whereas tardive dyskinesia is just brief movements.
Explain the phenomenon of orthopnea.
Orthopnea is a sign of left-heart failure. Left-heart failure will lead to edema throughout the body due to inadequate circulation. Much of the fluid pools in the lower extremities due to the force of gravity. When a person with LH failure lies supine, that fluid quickly returns to the right heart via increased venous return. If the left heart cannot match the output of the right heart, then fluid will pool in the lungs.
Paresthesia in the extremities and a papular rash on the groin area are indicative of a disorder that leads to the accumulation of what metabolite?
Globotriaosylceramide
Note: this accumulates in muscle tissue. The earliest sign of Fabry disease is inability to sweat due to loss of smooth muscles in sweat glands.
What demyelinating disorder that results from a missing enzyme presents with ataxia, seizures, and hypotonia?
Metachromatic leukodystrophy
This is a defect in arylsulfatase
What kind of pneumonia produces foul-smelling sputum?
Aspiration pneumonia
In addition to alcohol overdose, drug overdose, and neurologic disorders, _____________ can also produce aspiration pneumonia.
seizure disorders
Explain the utility of paraaminohippuric acid (PAH).
PAH is both filtered by and excreted by the kidneys. Also, it is NOT REABSORBED AT ANY POINT and so provides an approximation of renal blood perfusion.
What does this mean? Well, filtration into Bowman’s capsule is not saturable and is only limited by GFR. As such, the more PAH you put into the glomerulus, the more will be filtered. PAH is also excreted into the PCT. This is a carrier-protein mediated process that can be saturable. So if you increase the concentration of PAH, you will see the extraction ratio increase up to the point at which the carrier is saturated.
If a patient is hypoxemic but his A-a gradient is normal (i.e., 10 or less), then the etiology has to be one of two things: __________________.
hypoventilation or high altitude (or any other low-oxygen air inhalation)
PAH concentration is likely to be lowest in which part of the nephron?
Bowman’s space (because it is secreted into the PCT and not reabsorbed at any point)
True or false: in hypertrophic cardiomyopathy, the interventricular septum overrides the aortic valve and blocks the outlet.
False-ish. The mitral valve can randomly get pushed back toward the aortic valve in those with HOCM under stress (say, while exercising). When this happens, the mitral valve AND the interventricular septum block the aortic valve.
Give a rundown on the most important points about PCOS.
- The main abnormality is an elevated LH:FSH ratio. This leads to increased androgen production by theca cells.
- The androgens lead to hirsutism and infertility. Estrone levels rise when androgens are converted to estrogen peripherally.
- The elevated estrogen shuts off FSH production and thus follicles fail to develop.
- Unopposed estrogen leads to endometrial hyperplasia.
- Elevated LH leads to hypertrophy of the ovaries.
What are some key treatments for PCOS?
- Weight loss can often revert the whole axis back to normal.
- Diabetes treatment (metformin) can usually restore ovulatory function if a patient wishes to conceive.
- Another route to restore fertility is to use the SERM clomiphene! It blocks estrogen selectively at the pituitary/hypothalamus and thus tricks the body into secreting more FSH.
- In those who do not want any of the above, it is recommended that they take dual hormone OCPs which will decrease LH secretion and stop the unopposed estrogen high (to reduce risk of endometrial cancer).
_____________ make S. viridans able to adhere to fibrin.
Dextrans (synthesized from sucrose)
M. leprae invades which cells?
Skin and nerves
Cardiomegaly and hepatomegaly in a five-month-old will likely be present in a disorder that causes ________-positive samples on biopsy.
acid-Schiff (PAS)
This stains for glycogen and will be found in kids with Pompe disease.
What histologic pattern will contact dermatitis present with?
Spongiosus – accumulations of fluid in between cells of the epidermis
The right atrium and SVC are in very similar spots in an x-ray of the heart. What landmarks are they normally near?
- RA: below the right bronchi and roughly one or two ribs above the resting diaphragm
- SVC: about where the right bronchi is and three or four ribs above the resting diaphragm
Explain how UAA, UGA, and UAG stimulate release of mRNA from the ribosome.
The three stop codons bind to releasing factors in the cytosol that trigger the release of mRNA from the ribosome.
What cellular process leads to cavitation formation in lung diseases?
Release of lysosomal enzymes from macrophages and neutrophils
Which two vasculitis disorders present with granulomas of the media?
Takayasu and giant cell
Imagine a giant cell destroying a Japanese city called Takayasu –that would get a lot of MEDIA coverage.
People who get ABPA will typically have high levels of what two serum markers?
- IgE
* Eosinophils
Patients with membranous nephropathy often have antibodies to what?
Phospholipase A2 receptor (PLA2R) on podocytes
Note: this is what causes the immune deposits in MN.
What is one of the best ways to prevent kidney stones?
Proper hydration
This is true for all kinds of kidney stones.
What kind of purified viral genetic material can replicate in the cytoplasm?
(+) ssRNA
- dsDNA and ssDNA need RNA polymerase II –found in the nucleus –to make mRNA which can replicate in the cytoplasm
- dsRNA (i.e., Reoviruses) and (-)ssRNA need their own RNA-dependent RNA polymerases to make (+)ssRNA.
Why are conjugated vaccines given to young children?
Children younger than 2 years do not make an immune response to polysaccharide vaccines (e.g., the 23-valent S. pneumo vaccine). As such, these molecules must be conjugated to T cells to help recruit and activate B cells.
What is the molecule in Accutane?
ISOtretinoin
Be careful because tretinoin is a cream. (Think: Tretinoin is Topical.)
What disorder can present with elevated propionyl acid?
Ooh, this is hard. There are two:
- Defective propionyl CoA carboxylase leads to inability to metabolize propionyl to methylmalonic acid. Propionyl is a metabolite of valine, isoleucine, and methionine, so this accumulates quickly. Presenting symptoms are hypotonia, hypoglycemia, and lethargy in a newborn.
- Defective malonyl CoA mutase leads to elevated methylmalonic acid and propionyl. Presenting symptoms are similar.
Note: in both disorders, the excess organic acids inhibit the urea cycle leading to hyperammonemia. Additionally, the TCA has to run overdrive to keep up with the metabolism, so hypoglycemia and ketosis are common.
What intracranial tumors present with S-100 staining?
- Metastatic melanoma
- Schwannomas
Both of these cells are neural crest in origin, so hence the S-100 staining.
What intracranial tumor has a biphasic appearance with mixed cellularity and myxoid material?
Schwannomas
Unlike oligodendrogliomas, which have a fried egg look, Schwannomas have pink exudative material with areas of cellularity.
(Think of the Schwan truck distributing all that myxoid ice cream.)
What symptoms make up lateral medullary syndrome?
- Ipsilateral ptosis and miosis (disruption of the ascending sympathetic nerves)
- Ataxia (disruption of the spinocerebellar tract)
- Nystagmus (disruption of the vestibulocochlear syndrome)
- Contralateral hemiplegia (disruption of the descending corticospinal tract)
- Ipsilateral facial numbness
In a patient with a severe head injury with resultant midline shift, what causes extensor posturing?
Typically, the midline shift pushes down on the brainstem and disrupts the pons.
Pearl: extensor posturing results from damage below the midbrain.
By what mechanism does left heart failure lead to pulmonary hypertension?
The excess fluid congestion (from the left heart not moving it forward) leads to vasoconstriction via the myogenic response.
Not hypoxic vasoconstriciton!
Why are corticosteroids given to premature infants?
Steroids stimulate type II pneumocytes to produce surfactant.
Why do anovulatory cycles lead to heavy bleeding?
Ovulation triggers the release of progesterone and the decline of estrogen levels. Those changes promote a stabilization of the uterine wall. Without ovulation, estrogen remains high and continues to thicken the endometrial wall.
Why do you need to take a long time between MAO treatment and SSRI treatment?
Recall that MAO inhibitors are irreversible (the mouse is irreversibly killed by the mouse trap), so more MAO enzymes need to be synthesized before you can give an SSRI.
Congenital long QT syndrome results from mutations in _______________.
voltage-sensitive potassium channels
What makes pseudotumor cerebri worse?
Anything that increases intracranial pressure: bending down, Valsalva maneuver, coughing.
Note: this impairs “axoplasmic flow” to the eyes, thereby increasing
Where in the female reproductive organs is there cuboidal epithelium?
The germinal epithelium around the ovary!
If you can remember that this tissue is mesoderm, just think that this and the other mesoderm in the pelvis –the bladder –are both simple cuboidal.
What kind of epithelium lines the fallopian tubes?
Ciliated columnar
What role do valves play in the development of varicose veins in liver disease?
This is kind of tricky.
Normally, valves prevent backward blood flow. Continually increased venous pressure can dilate the veins and cause valve insufficiency!
Those with metachromatic leukodystrophy have build up of what metabolite?
Cerebroside sulfate
Atherosclerosis of the mesenteric arteries produces what symptom?
Pain roughly 30 minutes after eating
Failed fusion of the urethral folds in a male produces _____________.
hypospadias
______________ causes epispadias.
Abnormal position of the genital tubercle
What prevents C. difficile infection in a healthy person?
The microbiome (hence why antibiotics cause pseudomembranous colitis)
Vitamin E deficiency presents with hemolytic anemia, hyporeflexia, and ______________.
loss of proprioception
Those with a negative _______________ test are more likely to have lepromatous leprosy (as opposed to tuberculin leprosy).
lepromin skin test
This test assesses the strength of the T cell response to leprosy. If it positive –meaning lots of IFN-gamma, activated macrophages, and IL-1 –then it is likely that the person has tuberculin leprosy.
Why does sodium bicarbonate help TCA toxicity?
It raises the pH of the serum which favors the un-ionized form of the drug. The ionized form is what binds sodium channels and causes cardiac toxicity, so alkalinization helps prevent this.
What features should you look for to diagnose overflow incontinence?
- Some type of obstruction of urinary outflow (e.g., impaired detrusor contractility in diabetic neuropathy or tumor obstruction of the urethra
- Sudden uncontrollable urination WITHOUT prior sense of needing to go
- Enuresis
- Increased post-void residual volume (due to obstruction or weak detrusor not pushing all the fluid out)
What biochemical signals mediate the hypothalamic suppression seen in anorexics with amenorrhea?
Decreased leptin levels
This is kind of cool. When fat stores drop –such as from strenuous exercise, anorexia, or chronic illness –leptin levels drop. The decrease in leptin tells the hypothalamus to stop secreting GnRH and thus women stop having periods.
How can p-57 staining help diagnose hydatidiform moles?
Partial moles will be p-57 positive.
(Think of it like this: partial moles have 69 chromosomes, which is above 57. Complete moles have 46 chromosomes which is less than 57.)
The musculocutaneous nerve innervates which sensory area?
Lateral forearm
Describe the lymph drainage from the rectum and colon.
- Inferior 1/3 of rectum: inguinal nodes
- Middle 1/3 of rectum: internal iliac nodes
- Superior 1/3 of rectum: inferior mesenteric nodes
The rest of the colon follows the artery drainage
Injuries to the superior gluteal nerve produce what physical exam finding?
Contralateral hip drop while walking
Normally, the superior gluteal muscle pulls the iliac crest to the trochanter of the femur when standing on that leg alone (to help maintain balance). When this can’t happen, the hip rises and the contralateral hip falls.
Injections in the __________ area have a high probability of damaging the superior gluteal nerve.
superomedial portion of the buttocks
The PR interval is actually a misnomer. The distance is measured _____________.
from the start of the P wave to the start of the Q wave
What should you do if you learn that a patient has a serious illness but the patient tells you they don’t want to know any diagnostic/prognostic information?
Provided they are capable of making decisions (e.g., they aren’t intoxicated, delirious, demented, or cognitively disabled), then they are able to refuse hearing the information. Don’t tell them.
A patient presents with a peripheral lung mass. What histologic features can distinguish mesothelioma from adenocarcinoma?
• Mesothelioma:
- tonofilaments (think of the TV lawyers promising mesothelioma victims a TON OF money)
- long microvilli
- psammoma bodies
• Adenocarcinoma:
- glandular elements
- short microvilli
Recall that alpha-1-antitrypsin deficiency usually produces ________________ emphysema, while smoking produces ____________ emphysema.
lower-lobe, pan acinar; upper-lobe, centriacinar
Compare and contrast the molecular properties of elastin and collagen.
• Elastin:
- does not form a helix
- uses fibrillin as a scaffold
- has mostly neutral amino acids, but some lysine residues
- not hydroxylated post-translationally
- desmosine crosslinks form in which lysine is deaminated and binds to another lysine
•Collagen:
- forms a triple helix
- uses disulfide bonds to crosslink
- has lots of glycine-XX repeats
- many hydroxylated lysine and proline residues
Why does HDV need HBV to replicate?
HDV cannot enter host cells. It needs to be packaged into HBV envelope to become infectious.
(Think of the hippie parents who clothed their HDV kids in robes.)
True or false: a patient with koilonychia and dysphagia likely has an esophageal adenocarcinoma that is causing blood loss.
While this is possible, it’s much more likely that the patient has Plummer-Vinson syndrome. PVS is characterized by a triad of iron deficiency anemia, esophageal webs, and glossitis.
Which is more common, HCC or liver metastases?
Metastases (20x more common)
What type of drug is cyclobenzaprine?
Muscle relaxant
Explain each of the terms for adverse medication effects below: •Exaggerated sensitivity •Idiosyncratic reaction •Predictable drug reaction • Immune reaction •Pseudoallergy
- Predictable drug reaction: an effect that occurs in most people with dose-dependent frequency
- Exaggerated sensitivity: a known effect of a drug that occurring at a much lower dose than expected (e.g., tinnitus with one tablet of aspirin)
- Idiosyncratic reaction: a known effect that only occurs in rare cases and is not tied to dose
- Immune reaction: allergy to drug
- Pseudoallergy: a reaction that looks like an immune reaction (such as anaphylaxis), but that doesn’t involve immune cells
Naproxen can cause what side effect?
Gastric ulcers (it is an NSAID)
How does the concentration of dihydrotestosterone compare to the concentration of testosterone?
It usually parallels it and is slightly less than the concentration of testosterone. It has a similar half-life, so DHT will usually fall concurrently with testosterone.
Which branch of the splenic artery has poor anastomoses?
The short gastric
Explain what is meant by the fact that verapamil “slows diastolic depolarization.”
Verapamil blocks calcium channels in the SA and AV nodes. The SA node is what stimulates atrial contraction. Depolarization is mediated by voltage-sensitive calcium channels in the pacemaker cells. Blocking the calcium channels thus slows depolarization, which occurs during diastole.
Those with homocystinuria usually have elevated levels of what other amino acid?
Methionine
Because homocysteine can’t get converted to cystathionine, more of it gets shunted to methionine.
What is another term for the pseudodiverticula seen in diverticulosis?
Pulsion diverticula
The PULSing segmentation of the colon leads to pulsion outpouchings.
What toxic metabolite accumulates in fructose intolerance?
Fructose 1-phosphate
Why might a woman with primary biliary cirrhosis have pruritis?
Two mechanisms:
•PBC leads to the accumulation of bile acid in the skin.
•Insufficient fat absorption can lead to vitamin A deficiency which leads to hyperkeratosis.
Where is the AV node?
Near the coronary sinus in the interatrial septum
Note: UWorld says that “between the tricuspid valve and the IVC” is incorrect, even though it actually looks like it’s between the two. The coronary sinus is between the IVC and tricuspid valve, so that’s probably what they were getting at. The AV node is just superior to the coronary sinus in the septum.
Describe schizotypal personality disorder and what it might be confused with.
- Magical thinking (clairvoyance, superstition) that is not disabling –if it were disabling it would be considered schizophrenia
- Social anxiety even in the presence of family… don’t get tempted to put social anxiety disorder
Minimal change disease can precipitate after any disorder that ___________________.
induces a cytokine response: insect bites, vaccinations, or URIs
Which antibiotic can be deactivated by bacteria that develop acetylating mutations?
Aminoglycosides
The most sensitive pregnancy serum tests can detect b-HCG _________ days after fertilization.
8 days
Note: implantation doesn’t occur until roughly 6-7 days, so this is near the absolute limit. Urine levels aren’t detectable until about 14 days.
A woman presents with near-complete occlusion of the left anterior descending artery, but she doesn’t have any myocardial necrosis. What most likely explains this discrepancy?
Slow growth of the atheroma
If an occlusion grows slowly, then anastomoses can develop from the right coronary and prevent necrosis.
Why does muscarinic inhibition lead to flushing?
Eccrine sweat glands are stimulated by acetylcholine. If you inhibit this then sweating is prevented. Blood vessels dilate to help give off heat.
Describe cystic medial degeneration.
Normally the tunica media has a woven look because of the elastic fibers. In cystic medial degeneration, little holes develop between the elastic fibers and fill with myxomatous material. This progresses until lots of little holes develop in it. This weakens the wall and leads to degeneration.
Note: sweet peas contain an enzyme that inhibits lysyl oxidase which prevents the springiness of elastin. This mimics Marfans.
What is a false aneurysm?
When a hole develops in an artery, blood can fill in the connective tissue outside the artery. It looks like an aneurysm, but it’s actually a hematoma.
How is the glucose fermentation of Shigella distinct from that of E. coli?
Shigella produces acid while E. coli produces gas.
