3/24 - UW 21 Flashcards
What are the 3 most common brain tumors in children?
- Pilocytic astrocytomas
- Medullobalstomas
- Ependymomas
What is the most common location for pilocytic astrocytomas?
Cerebellum
A child presenting with a cerebellar mass with both solid and cystic components, showing Rosenthal fibers on microscopy is indicative of what tumor?
Pilocytic astrocytoma
What is the most common location for Medulloblastomas?
Cerebellum (vermis) almost exclusively
What is the most common malignant brain tumor in children?
Medulloblastoma
What brain tumor in children shows sheets of small blue cells with hyperchromatic nuclei and scant cytoplasm in the cerebellum?
Medulloblastoma
Where are Ependymomas found?
In the ependymal lining of the ventricles, may obstruct CSF flow
What is absorbed primarily in the ileum?
Bile, B12
What proteins facilitate the “Rolling” phase of leukocyte accumulation?
L-selectin on neutrophils, E- or P-selectin on endothelial cells
How do the “Tight adhesion and crawling” phases of leukocyte accumulation happen?
Neutrophils use by [CD18beta2 integrins (Mac-1/LFA-1)]
to attach to
[Intercellular adhesion molecule-1 (ICAM-1)] on endothelial cells
What molecule facilitates the “Transmigration” (final) phase of leukocyte accumulation?
Platelet endothelial cell adhesion molecule 1 (PECAM-1)
What type of inheritance are the 3 leukocyte adhesion deficiency (LAD) syndromes?
Rare, AR
What causes leukocyte adhesion deficiency (LAD) syndrome?
CD18 defect, no pus, delayed umbilical detachment
What complication of subarachnoid hemorrhage can present 4-12 days later with new onset confusion/focal neuro deficit?
Vasospasm due to impaired brain autoregulation
How do you prevent vasospasms post-subarachnoid hemorrhage
Nimodipine (selective Ca channel blocker)
Why would you hyperventilate a patient with cerebral edema?
Hyperventilation causes hypocapnea, which decreases cerebral blood flow
Unexplained medical symptoms with excessive health care use are characteristic of what?
Somatic symptom disorder
What is the best first step in management of Somatic Symptom Disorder?
Regular scheduled visits with the same PCP
What is the TTAGGG repeat at the 3’ end of chromosomes?
Telomeres, added by Telomerase
What is the RNA template used by telomerases?
TERC template (built into the telomerase enzyme)
What type of cells have active telomerases?
Stem cells (e.g. embryonic, epidermal, bone marrow)
What does the proto-oncogene Ras encode?
G protein that activates the MAPK pathway, affecting downstream transcription
What is the mechanism for nitrite antidote for CN?
Nitrites convert Hgb to metHgb, which is worse for O2 carrying, but better for CN sequestration, preventing it from damaging the mitochodrial ETC
What is kinesin?
Microtubule associated motor protein that functions in anterograde transport of intracellular vesicles towards the (+) end
What is the mechanism for nitrate induced smooth muscle relaxation?
Nitrate converted to NO. NO stimulates GTP conversion to cGMP, which decreases [Ca]. Decreased Ca dephosphorylates myosin light chain, relaxing the smooth muscle cell.
Tricyclic anti-depressants can mimic what class of antiarrhythmics?
Quinidine (class IA): QRS and QT prolongation
What to give for TCA-induced cardiotoxicity?
Hypertonic sodium bicarb (corrects QRS prolongation, reverse hypotension, treat ventricular disrhythmias
What side effects of opioids do not exhibit tolerance?
Constipation and miosis
What vitamin should be avoided with levodopa administration?
B6, which increases peripheral metabolism of levodopa
What causes ataxia, nystagmus, opthalmoplegia, and anterograde amnesia in an alcoholic?
Thiamine deficiency induced Wernicke’s encephalopathy
What brain structure is most affected in thiamine deficiency?
Mammillary body
What fetal abnormality can be seen with Valproate?
Neural tube defects (due to inhibition of intestinal folic acid absorption)
What is Ebstein’s anomaly?
Congenital “atrialized right ventricle” due to downward displacement of tricuspid valve, seen in maternal Lithium use
What fetal cardiac abnormality is seen in maternal Lithium use?
Ebstein’s anomaly, where the tricuspid is downwardly displaced
What is the maintenance (oliguric) phase of acute tubular necrosis (ATN)?
After the initial insult (initiation phase), GFR stabilizes at low level, oliguric. Lasts for 1-2 weeks. Shows granular casts in tubular lumina, and epithelial necrosis with denudation of basement membrane on microscopy
What is seen in the recovery phase of ATN?
Re-epithelization of tubules. Polyuria and GFR normalization.
Hypersegmented neutrophils with neurologic deficits = ???
B12 deficiency!
What is the difference in joint involvement between gout and pseudogout?
Gout: 1st metatarsophalangeal jt
Pseudogout: knee
What crystals are seen in pseudogout?
Rhomboid-shaped calcium pyrophsphate, birefringent (blue parallel, yellow perp)
DVT tx in pregnancy??
Heparin!
What anticoagulant is not used in pregnancy? Why?
Warfarin, due to teratogenicity
What anticoagulant might you give for CAD, PVD, or cerebrovascular disease?
Clopidogrel
Clopidogrel MOA?
Inhibition of ADP mediated platelet aggregation
What neoplasm shows KERATIN PEARLS on microscopy?
Squamous cell carcinoma
What neoplasm shows “ground glass” nuclei in cuboidal cells covering a fibrovascular stalk?
Papillary thyroid carcinoma
What type of angina is episodic, transient, nocturnal, with temporary ST elevation?
Prinzmetal’s (variant) angina
What causes Prinzmetal’s angina?
Vasospasms near atherosclerosis causing transient transmural ischemia
What is the best diagnostic test for Prinzmetal’s angina?
Ergonovine test (ergot alkaloid that stimulates alpha and 5HT receptors causing vascular smooth muscle constriction)
What do you use Ergonovine to test for?
Prinzmetal’s angina
