NBME 28 incorrects Flashcards
What is the purpose of a mixing study? (coagulation disorders)
If person is factor deficient, then mixing with normal serum will return PT/PTT to normal levels but if there is an inhibitor it will not.
What lab values do you expect for Hemophilias?
Prolonged PTT but normal PT
What lab values would you expect for vitamin K deficiency
Prolonged bleeding time, PT, and PTT
What lab values would you expect for Von Willebrand disease?
Prolonged bleeding time and PTT
Normal platelet count and and PT
No platelet aggregation with risotcetin cofactor assay
What lab values would you expect for D.I.C.
Prlonged bleeding time, PT, PTT and decreased platelets
widespread clotting factor activation
What is the difference between bernard soulier syndrome and von willebrand?
Bernard Soulier syndrome which is due to deficiency in gpIb and VWF is deficiency of VWF
Pt presents with pronged bleeding time normal platelet count but on smear no platelet clumping.
Glanzmann thrombasthenia. due to decreased GpIIb/ IIIa
Pt w/ history of lupus presents with increased bleeding time, decreased platelets and on bone marrow biopsy they have megakaryocytes
Immune thrombocytopenia. due to antibodies to GpIIb/IIIa
Thrombocytopenia (decreased platelets), decreased hemoglobin, schistocytes, increased LDH, and Increased creatine (kidney injury).
Normal PT/PTT
thrombotic microangiopathy (TTP/ or HUS)
Woman comes in with recurrent miscarriages, she also recently had a DVT and now presents with cerebral venous thrombosis (headache and papilledima)
she has factor V deficiency
Definition of relative risk.
Incidence rate of the exposed group divided by the incidence rate of the unexposed group. It is the likelihood an outcome based on if you were exposed versus if you were not exposed.
How do NSAIDs affect GFR
Prostaglandins dilate the Afferent arteriole, so NSAIDS it decrease GFR
how do ACE inhibitors affect GFR
angiotensin II constricts the efferent leading to an increase in GFR. So inhibiting it with an ACE inhibitor DILATES the efferent arteriole leading to a DECREASE in GFR
What two drugs can aminoglycosides work synergistically with?
Penicillins and monobactams
What two drugs can aminoglycosides work synergistically with?
Penicillins and monobactams
Boy presents with intellectual disability, long face, prominent ears and large testicles. What is the disease?
Fragile X syndrome due to trinucleotide repeat
Most common fractured carpal bone?
Scaphoid and presents with pain in anatomical snuffbox. need to treat bc it can lead to avascular necrosis
Most common dislocation during a FOOSH
lunate bone which can impinge medial nerve and cause carpal tunnel
what does CN 9 innervate
glossopharyngeal nerve provides motor and sensory information to stylopharyngeus nerve which helps with swallowing. also innervates parotid gland and provide sensory information to pharynx
what part of the colon are diverticula most common?
sigmoid because it is the narrowest
Monoclonal antibody that inhibits glycoprotein IIb/IIIa which inihibits platlet aggregation by that normally occurs because of binding with fibrinogen
Abciximab
binds to adenosine diphosphate receptor (P2Y12 receptor) to inhibit platlet aggregation
clopidigrel
phosphodiesterase III inhibitors reduce the degredation of adenosine
cliostazol and dipyridamole
how does the liver or kidney regenerate after injury
in healthy indviduals the majority of cells are in G0 phase and can re-enter G1 phase after injury
Pathogenesis of graves disease
Autoantibody that stimulates thyroid stimulating hormone receptors on thyroid follicular cells
Myeloperoxidase deficiency MOA
inability to produce hydrochlorous acid within phagolysosomes
Femoral neck fracture would cause?
Foot drop. because common peroneal nerve innervates dorsiflexion
What is the mechanism of action of the pertussis toxin
It causes intracellular cAMP through inactivation of the Gi subunits of G protein couple receptors leading to unihibited adenylyl cyclase activity
when is creatine kinase MB detectable after an MI?
6 hours
What is CK MB indicative of?
coagulative necrosis due to increased cell membrane permeability which causes leaking of CK MB out of cytoplasm
what is the definition of odd’s ratio
comparision of an outcome in the exposed group versus the outcome of an outcome in the unexposed group
what happens during muscle disuse atrophy
Decrease in protein muscle synthesis and an increase in protein degradation.
what amino acids do astrocytes transport?
glutamate, glycine, GABA
where do Beta 1 receptors target
heart–> myocardial contraction
Beta 2 receptor location
smooth muscle of bronchi and blood vessels, decreased uterine contractility
what causes the formation of granulomas?
activation of IL-12 and IFN gamma
Pathophysiology of hemochromatosis?
Mutation of HFE gene (iron sensing gene) which leads to abnormally increased intestinal absorption of iron
sudden onset of pain, pulseless, cold extermity
embolic arterial occulusion
Encephalomyopathy, lactic acidosis, reoccuring stroke-like episodes. Maternally inherited
Mitochondrial myopathy-MELAS
What enzyme is deficient in facial flushing after alcohol consumption?
aldehyde dehydrogenase
What happens between muscle contraction stimulus
sequestration of calcium in sarcoplasm reticulum to allow for relaxation
What is tetany?
Increased firing that does not allow for any relaxation to occur and no calcium sequestration
What infections are common in patients with chronic granulomatous disease?
catalase positive organsims. Staph, norcordia, burkholderia, asperigullus
what kind of infections do patients with myeloperoxidase deficiency have?
Fungal
where does osteosarcoma usually metastasize too?
Lungs
what would be found on fine needle biopsy of a pt. diagnosed with hashimoto’s
lymphoid infiltrate with presence of hurthle cells
what is the antibody in hashimoto thyroiditis?
antithyroglobin and antihryoid peroxidase antibodies
