5/23 Mixed Flashcards
Phenoxybenzamine
An irreversible a1 and a2 adrenergic antagonist that effectively reduces the arterial vasoconstriction induced by NE. Because phenoxybenzamine is an irreversible antagonist, even very high concentrations of NE, such as those seen in phenochromocytoma, cannot overcome its effects
Glucocorticoids
Potent stimulators of liver gluconeogenesis (anabolic in the liver)…otherwise predominantly catabolic
Favor catabolism and proteolysis in skeletal muscle
Adrenal cortex atrophy
Decrease bone mass
Potent immunosuppressive agents
Inhibit fibroblast proliferation and collagen formation in skin
Deletion or addition of number of bases that is not divisible by 3 in the coding region of a gene will causes
A frameshift mutation
Alters the reading frame of the genetic code, resulting in formation of nonfunctional proteins
Adrenal Insufficiency
Not able to increase glucocorticoid production in response to acute stress (illness, surgery)
Adrenal crisis is characterized by severe hypotension, abdominal pain, vomiting, weakness, fever
Weight loss/hyperpigmentation are suggestive of chronic primary adrenal insufficiency (Addison’s disease)
In addition to aggressive fluid resuscitation, treatment requires immediate glucocorticoid supplementation
History of hypothyroidism puts pts at increased risk for other autoimmune endocrinopathies (autoimmune adrenalitis)
Minors can consent to the following without emancipation or parental consent/notification
Prenatal care
Diagnosis/treatment of STD
Contraception
Drug or alcohol rehabilitation
Porphyria cutanea tarda (PCT)
Most common disorder of porphyrin (heme) synthesis)
Late step derangements cause photosensitivity (due to accumulation of porphyrinogens) that react with oxygen on excitation by ultraviolet light
PCT is caused by uroporphyrinogen decarboxylase deficiency (inherited or acquired due to presence of iron, alcohol, smoking, halogenated hydrocarbons, hep C, HIV)
Photosensitivity presents as vesicle and blister formation
(also edema, pruritus, pain, erythema)
Rituximab
Monoclonal antibody against CD20 antigen
Improves the prognosis of some lymphomas
Non-Hodgkin T cell lympoma that strongly stains for CD20 marker
Strongyloides stercoralis
Begins following skin penetration by filariform (infectious) larva
Dx: rhabditiform (noninfectious) larvae in the stool
Rhabditiform larvae can mature into filariform larva in the human GI tract, precipitating autoinfection
Can result in hyperinfection syndrome > massive dissemination of organism, multiorgan dysfunction, septic shock
How are viral proteins degraded before being expressed on MHC I for presentation to cytotoxic CD8 lymphocytes?
Ubiquitin proteasome pathway, controlled by ubiquitin ligases
Dengue virus
Single stranded RNA virus with 4 different serotypes
Primary infection can be asymptomatic or cause a self-limited disease in most adults
Secondary infection is due to infection with a different viral serotype and usually causes more severe illness (antibody dependent enhancement of infection)
Marked thrombocytopenia, prolonged fever, respiratory/circulatory failure, shock, petechiae, macular rash, muscle and joint pain (“break bone fever”)
Transverse Spinal Cord Sections
Moving rostrally, spinal levels have increasing amounts of white matter, decreasing amounts of gray matter, and are more oval shaped
Lower cervical and lumbosacral regions have large ventral horns
Thoracic and early lumbar sections contain lateral gray matter horns (intermediolateral cell columns)
Gracilea dn cuneate fasciculi are present above the T7 spinal levels, whereas only the gracile fasciculus is present below this level
Regression of Paramesonephric (mullerian) duct
Mullerian inhibiting factor (MIF)
Secreted by the embryonic testis
Normally give rise to the internal genitalia in the female fetus
Region of the sarcomere that contains only thick filaments
The H band (Dark)
Syringomyelia
Combination of fixed segmental loss of upper extremity pain and temperature sensations, upper extremity lower motor neuron signs, and or lower extremity upper motor neuron signs in the setting of scoliosis
Progressively weakening diaphragmatic contractions during maximal voluntary ventilation with intact phrenic nerve stimulation indicate….
Neuromuscular junction pathology (e.g. myasthenia gravis) and/or abnormally rapid diaphragmatic muscle fatigue (e.g. restrictive lung or chest wall disease)
Patients with noncoronary atherosclerotic disease, diabetes mellitus or chronic kidney disease are at the same risk of cardiovascular events (MI, stroke) as patients with known coronary artery disease
Coronary heart disease is the most common cause of death in patients with diabetes mellitus
GI disorder in CF patinets
Pancreatic insufficiency
Mutations in CFTR lead to thick, viscous secretions in the lumens of pancreas leading to OBSTRUCTION, INFLAMMATION, and subsequent FIBROSIS
Protein M
Major virulence factor for Strep pyogenes
Protein M
The major virulence factor for Strep pyogenes
Inhibits phagocytosis and complement activation, mediates bacterial adherence, target of type-specific humoral immunity to S. pyogenes
Dx of cholecystitis
Identifying signs of gallbladder inflammation (wall thickening, pericholescystic fluid) on US
Nuclear medicine hepatobiliary scanning (cholescintigraphy) can be used to assess cystic duct patency when ultrasound in inconclusive (failed gallbladder virusalization on radionuclide biliary scan)
Treatment of Organophosphate poisoning
Organophosphates stimulate both muscarinic and nicotinic cholinergic receptors
Atropine reverses muscarinic effects but does not prevent the development of nicotinic effects such as muscle paralysis
Pralidoxime is the only medication that reverses both muscarinic and nicotinic effects of organophosphates by restoring cholinesterase from its bond with these substances
Hyperacute rejection
Mediated by preformed anti-donor antibodies in the recipient that attack the transplanted organ (type II hypersensitivity)
Occurs immediately upon initial perfusion of the transplated organ and is often diagnosed intraoperatively due to mottling and cyanosis of the organ
Risk of progression of diabetic nephropathy in patients with proteinuria can be reduced by
Appropriate glycemic and blood pressure control
ACE inhibits and angiotensin II receptor blocks are the preferred antihypertensive agents due to their blood pressure independent anti-proteinuric effects
Cholesterol gallstones
High cholesterol
Low bile salts
Low phosphatidylcholine
(Bile salts and phosphatidylcholine increase cholesterol solubility and decrease the risk of gallstones)
All patients with nephrolithiasis should be advised to….
consume ample water and clear liquids
Urine supersaturation is the main mechanism underlying all types of renal stones
low fluid intake increases the concentration of stone-forming agents, promoting stone formation
SE Fibrinolytic therapy for acute STEMI
Hemorrhage (gastrointestinal, intracerebral)
Herpes Zoster (shingles)
Intranuclear inclusions in keratinocytes and multinucleated giant cells are seen on light microscopy (positive Tzanck smear)
Giant cell arteritis
Granulomatous inflammation of the media and predominantly involves medium to smaller branches of the carotid artery, especially the temporal artery
Symptoms respond promptly to glucocorticoid therpy
Rx Clostridium difficile infections
Oral metronidazole, vancomycin, or fidaxomicin
Metronidazole and vancomycin are first-line treatments
Fidaxomicin is used primarily to treat recurrent CDI and is bacteriocidal, macrocyclic, with minimal systemic absorption
Drug Induced Parkinsonism
Type of extrapyramidal symptom
caused by medications that block D2 receptors
Management strategies include decreasing or discontinuing the offending medication and treatment with an anticholinergic antiparkinsonian medication
Sabin poliovirus vaccine vs. Salk vaccine
The live attenuated oral (Sabin) poliovirus vaccine produces a stronger mucosal secretory IgA immune response than does the inactivated poliovirus (Salk) vaccine.
This increase in mucosal IgA offers immune protection at the site of viral entry by inhibiting attachment to the intestinal epithelial cells
Penetrating laterally directed stab wound that involves the fifth intercostal space and the left anterior midclavicular line
Would injure the left lung
The left ventricle forms the apex of the heart and can reach as far as the fifth intercostal space at the left midclavicular line. All other chambers of the heart lie medial to the left MCL. The lungs overlap much of the anterior surface of the heart
C1 inhibitor (C1INH) deficiency
Causes increased cleavage of C2 and C4 and results in inappropriate activation of the complement cascade
C1INH also blocks kallikrein-induced conversion of kininogen to bradykinin, a potent vasodilator associated with angioedema
Calculating filtration fraction
FF= GFR/RPF
GFR can be estimated by the insulin or creatinine clearance
RPF is calculated using the para-aminohippuric acid clearance
Clearance = (urine concentration of S x urine flow rate of S)/ plasma concentration of S
Usually equal to 20% in healthy individuals
Blood supply to the femoral head and neck
Medial femoral circumflex artery
Injury to these vessels due to a displaced femoral neck fracture can cause osteonecrosis of the femoral head
Mitochondrial myopathy
Lactic acidosis and ragged skeletal muscle fibers histologically
Variable clinical expressions in affected family members can occur due to HETEROPLASMY, which is the coexistence of distinct versions of mitochondrial genomes in an individual cell
Hydrocephalus in infants
Macrocephaly and poor feeding
Imaging studies show enlarged ventricles
Untreated hydrocephalus leads to spasticity (muscle hypertonicity) due to stretching of the periventricular pyramidal tract, developmental delays, and seizures
Superior vena cava syndrome
Caused by intrathoracic spread of bronchogenic carcinoma compressing the superior vena cava, causing impaired venous return from the upper part of the body
Signs and symptoms include dyspnea, facial swelling, and dilated collateral veins in the upper trunk
MEDIASTINAL MASS!
Reactive arthritis
Nongonococcal urethritis, conjunctivity, arthritis
HLA-B27 associated arthropathy that occurs within several weeks following a genitourinary or enteric infections
Seronegative spondyloarthropathies
can cause sacroiliitis in 20% of cases
Multiple Endocrine Neoplasia type 2B (MEN2B)
Medullary thyroid CA, pheochromocytoma, mucosal neuromas, marfanoid habitus
Pheochromocystomas presents with episodic headaches
Mechanism of insulin resistance
Phosphorylation of serine and threonine residues of insulin receptor and insulin receptor substrate by serine kinases leads to insulin resistance
This type of phosphorylation can be induced by TNF-a, catecholamines, glucocorticoids, and glucagon
