NBME Test #1 Flashcards
What is most important in maintaining blood pH near 7.4? What would change these values?
Most important = bicarbonate-carbonic acid buffer –> changes in ventilation impact the relationship of the buffer and are responsible for compensation for acid-base disturbances. Breathing in low PO2 = hyperventilation = less PCo2 = alkalosis
What is specificity? What decreases sensitivity?
Proportion of all people with the disease who test positive for the disease. Moving cut point higher decreases sensitivity?
What is M protein associated with? What are some other symptoms of this disease?
M spike most associated with multiple myeloma, which presents with bone pain, anemia, hypercalcemia, renal dysfunction, and lytic bone lesions
How does an AV Fistula impact pressures and cardiac output?
Increases right atrial pressure and increases cardiac output due to the increase in preload. AVF = abnormal artery/vein communication = low resistance and high volume flow
Characteristics of Pierre Robin Syndrom
Presents at birth with small jaw, downward displacement of tongue, celft palate –> can lead to airway obstruction, hypoxia, issues with feeding. Caused by defect in first pharyngeal arch
What develops from each pharyngeal arch?
First: maxilla, mandible, masseter, pterygoids, mylohyoid, CN V2 and V2
Second: Middle ear, hyoid bone, temporal styloid process, muscles including facial muscles, CN VII
Third: Stylopharyngeus muslce and glossopharyngeal nerve
Fourth: Cricothyroid and muscles of soft palate, thyroid
Sixth: All intrinsic muscles of larynx except cricothyroid
In mycobacterium tuberculosis, what is the virulence factor? How does it act?
Cord factor = glycolipid on surface of cell wall that protects the bacteria from phagocytic killing and is directly toxic to macrophages
What is Kaposi sarcoma? How does it present? What does biopsy show?
Low-grade neoplasm of vascular endothelial cells with raised, erythematous cutaneous plaques that are reddish-purple. On histology, see slit-like vascular spaces with proliferation of spindle cells and is usually caused by HHV-8.
What factor can increase cerebral blood flow?
Serum carbon dioxide directly increases/decreases cerebral blood flow: hypocapnia = cerebral vasoconstriction and hypercapnia = cerebral vasodilation. Changes in MAP have minimal impact on CBF.
What is the difference between Hunter and Hurler syndrome? What are they characterized by?
Both are mucopolysaccharidoses = enzyme deficiency
- Hurler caused by a-iduronidase and Hunter caused by iduronate-2 sulface resulting in heparan sulafe and dermatan sulface
Hurley = AR, first year of life, coarse facial features, corneal clouding, hepatosplenomgaly, joint contractures, developmental delay
Hunter = x linked recessive and milder, no corneal clouding
What test is used to test cerebellar dysfunction? What about other neuro tests? (Babinski, Dolls eye, Glabellar tap, tinel?)
Rapid alternating movements
Babinski: upper motor neuron sign for damage to corticospinal tract
Dolls eye: brainstem reflex
Glabellar tap: blinking from tapping –> primitive related to frontal lobe immaturity
Tinels: median nerve –> carpal tunnel
What is the typical presentation of sarcoidosis?
SOB and cough in a younger, african american female associated with uveitis, erythema nodosum, and bilateral hilar lymphadenopathy with noncaseating granulomas
What are classic physical exam findings associated with pleural effusion? How is this different from lobar pneumonia?
Unilateral decreased breath sounds, dullness to percussion, decreased tactile fremitus, in lobar pneumonia –> coughing, fever, chills, INCREASED tactile fremitus
Preventing polymerization of actin filaments would impact what function of leukocytes?
Phagocytosis –> permits extension of cell membrane around pathogen to allow for encapsulation and internalization
What is the pattern of sarcomeres in left ventricular hypertrophy? What about in dilated cardiomyopathy?
LVH: Increased sarcomeres in parallel with each other to generate grader contractile force to overcome higher afterload
Dilated cardiomyopathy: Increased sarcomeres in series - cardiac myofibrils lengthen
In pediatric patients, what is the difference between viral synovitis and septic arthritis?
Septic arthritis: trauma, bacteremia, fever, chills, myalgias, nausea, painful swollen joint with limited ROM, often knee and hip, leukocytosis, increased erythrocyte sedimentation rate and c-reactive protein
Viral synovitis: viral infection causes inflammation often in hip, but NO leukocytosis and only mildly elevated ESR and c-reative protein
What is fibronectin? What is its role?
Critical component of extracellular matrix that is secreted from cells into extracellular space
How does acute intermittent porphyria present? What accumulates? whats different in porphyria cutanea tarda?
Sx: psychosis, abdominal pain, burgundy urine following a medication exposure = acute intermittent porphyria
Mutations of enzyme porphobilinogen deaminse = can’t synthesize heme = accumulation of porphobilinogen which is neurotoxic. NO photosensitivity.
Porphyria cutanea tarda = Uroporphyrinogen decarboxylase and get cutaneous photosensitivity/blistering
What is the mechanism of metformin?
Decreases gluconeogenesis, increases glucose uptake, and decreases serum free fatty acid concentration. Side effects include nausea, abdominal discomfort, diarrhea and RARELY, but importantly, lactic acidosis.
What is the mechanism of erectile dysfunction meds? What is their name?
Phosphodiesterase inhibitors that directly relax smooth muscle of the vasculatore of corpora cavernosa which leads to erection. Work by overriding sympathetic input that usually vasoconstricts to extinguish erections.
What are the actions of the rotator cuff muscles?
Internal rotation: subscapularis
External rotation when adducted: teres minor
External rotation: infraspinatus
Abduction: supraspinatus
What helps with scar remodeling and wound healing?
Matrix metalloproteinases, which help breakdown extracellular matrix and breakdown of bone/cartilage. necessary for healing of wounds.
How does Vitamin E deficiency present?
Usually protects erythrocytes from free radical damage, so deficiency = hemolytic anemia and generalized muscle weakness, but NO megaloblastic anemia/hypersegmend neutrophils
What organisms cause cellulitis? How does it present?
Cutaneous erythema, warmth following inoculation from an injurty like an abrasion. Fever, tachycardia, leukocytosis.
Two most common pathogens: Staph Aureus and Streptococcus Pyogenes (Group A)
What is proliferative glomerulonephritis? How is this different from minimal change disease?
Presentation: Children, nephritis dynrome following acute pharyngitis, usually follows strep pyogenes.
Nephritic syndrome with gross/microscopic hematuria and RBC casts, as well as proteinuria.
Minimal change disease is most common NEPHROTIC syndrome in kids triggered by recent infection.
What is the mechanism of gemfibrozil and pioglitazone?
Pioglitazone: binds to peroxisome proliferator activated receptors (PPARs) = increased insulin sensitivity
Gemfibrozil = fibrate lipid lower agents that activates PPARs and up-regulates lipoprotein lipase = decreased LDL, increased HDL, decreased triglyceride concentrations
How do you access the renal arteries from the femoral artery? What does the celiac trunk, internal iliac arterys, and SMA supply?
Advance just superior to the testicular artery.
Celiac trunk: –> common hepatic, left gastric, splenic artery supplying liver, stomach, proximal duodenum, pancreas, inerior esophagus, and spleen
Internal Iliac arteries: Branches of common iliac –> buttocks and pelvic organs including bladder but NOT the kidneys
SMA: branch of abdominal aorta, supplies duodenum, jejunum, ileum, and proximal 2/3 of the colon
What is the formula for steady-state concentration?
