UWorld Flashcards
Leukotriene B4
stimulates neutrophil migration to sites of inflammation. Other important chemotactic agents include 5-HETE (leukotriene precursor), complement component C5a, and IL-8
The morphology of Candida includes branching pseudohyphae with blastoconidia (budding cells). Most species are susceptible to ….
echinocandins, and C albicans is nearly always susceptible to fluconazole.
Urinalysis in patients with Chlamydia trachomatis infection classically shows ….
sterile pyuria (positive urine white blood cells, no bacteria on Gram stain, no growth on culture) because the C trachomatis bacterium is an obligate intracellular bacterium with minimal peptidoglycan in its cell wall. The diagnostic test of choice is nucleic acid amplification testing.
Thrombotic thrombocytopenic purpura classically presents with the pentad of ….
severe thrombocytopenia, microangiopathic hemolytic anemia (eg, schistocytes on peripheral smear), renal insufficiency, neurologic symptoms, and fever. However, all these signs and symptoms are rarely present. Diagnosis is often made by identifying severe deficiency of ADAMTS-13, a protease that cleaves large von Willebrand factor multimers off the endothelium
TTP labs
Hemolytic anemia (↑ LDH, ↓ haptoglobin) with schistocytes on peripheral smear
Thrombocytopenia (↑ bleeding time, normal PT/PTT)
Sometimes with:
Renal failure
Neurologic manifestations
Fever
Glutamate causes hyperactivation of what….
Glutamate is released from injured neurons, causing pathologic hyperactivation of NMDA receptors and leading to depolarization, calcium overload, and death of neighboring cells. This cascade of excitotoxicity contributes to neurodegeneration and propagation of neuron death after focal injury.
What do you give burn patients to prevent protein catabolism?
Patients with severe burn injury commonly develop a hypermetabolic response that results in an increased basal metabolic rate and, often, lean muscle wasting. Administration of oxandrolone, a synthetic testosterone analogue, enhances muscle protein synthesis and decreases protein catabolism, reducing lean muscle loss.
How does doxycycline work?
Rocky mountain spotted fever is a tick-borne illness due to Rickettsia rickettsii, a weakly gram-negative, obligate intracellular organism that has an affinity for vascular endothelial cells. Patients usually have nonspecific symptoms (eg, fever, malaise, myalgia) followed by a macular-petechial rash that begins on the ankles and wrists and spreads to the center of the body as well as to the palms and soles. Urgent treatment with doxycycline, an inhibitor of bacterial protein synthesis, is required.
Labs/Xrays for RA
Positive rheumatoid factor & anti–CCP antibodies
C-reactive protein & ESR correlate with disease activity
X-ray: soft tissue swelling, joint space narrowing, bony erosions
whats defective in Xeroderma pigmentosum
Xeroderma pigmentosum is an autosomal recessive disorder characterized by defective nucleotide excision repair often caused by a deficiency in UV-specific endonuclease. Affected children usually have severe photosensitivity, hyperpigmentation in sun-exposed areas, and a greatly increased risk for skin cancer.
Giant Cell arteritis
Giant cell arteritis (GCA) is characterized by granulomatous inflammation of the mediawith fragmentation of the internal elastic lamina most often affectingthe medium and small branches of the carotid artery. Ischemic optic neuropathy with irreversible blindness is a potential complication of GCA; therefore, patients with suspected GCA require immediate glucocorticoid therapy.
How does colchicine work?
Colchicine is a second-line agent for treating acute gouty arthritis. It inhibits tubulin polymerization and microtubule formation in leukocytes, reducing neutrophil chemotaxis and emigration to sites inflamed by tissue deposition of monosodium urate crystals. Gastrointestinal mucosal function is also impaired by microtubule disruption, leading to diarrhea and, less commonly, nausea, vomiting, and abdominal pain.
What is GFAP?
Glial fibrillary acidic protein (GFAP) is normally found in glia, and tumors of glial lineage are often positive for GFAP. Synaptophysin is normally found in neurons and neuroendocrine cells; tumors with neuronal or neuroendocrine differentiation are typically positive for synaptophysin.
metabolic acidosis, NAG
loss bicarb: diarrhea, RTA, excessive saline infusion
metabolic acidosis elevated anion gap
acc of. acidic compounds: LA, diabetic ketoacidosis, renal failure, methanol, ethylene glycol, salicylate toxicity
what initially offsets PE in heart failure
lymph drainage, increased
what does FAS do
The Fas receptor acts to initiate the extrinsic pathway of apoptosis. Mutations involving the Fas receptor or Fas ligand can prevent apoptosis of autoreactive lymphocytes, thereby increasing the risk of autoimmune disorders such as systemic lupus erythematosus.
What receptor important to isotype switch
Isotype switching is the process through which activated B lymphocytes switch production from IgM immunoglobulins to IgG and IgA isotypes. This process requires the interaction of CD40 on activated B cells with CD40 ligand expressed by activated T cells and is modulated by cytokines secreted by T cells.
What can cause ineffective hematopoesis
Folate is essential for nucleic acid metabolism, and deficiency causes ineffective hematopoiesis with a low reticulocyte count. Characteristic megaloblastic changes include hypersegmented neutrophils and macrocytic red blood cells. Macrocytic erythrocytes are prone to hemolysis, which can increase serum bilirubin and lactate dehydrogenase.
The chronic myeloproliferative disorders (polycythemia vera, essential thrombocytosis, and primary myelofibrosis) often have a mutation in what?
Janus kinase 2 (JAK2), a cytoplasmic tyrosine kinase. This results in constitutive tyrosine kinase activity, and consequently, in the cytokine-independent activation of signal transducers and activators of transcription (STAT) proteins (JAK-STAT signaling pathway).
ANP and BNP
secreted by atrial and ventricular cardiomyocytes in response to myocardial stretching induced by hypervolemia. These natriuretic peptides inhibit the renin-angiotensin-aldosterone system and stimulate peripheral vasodilation and increased urinary excretion of sodium and water. Neprilysin inhibitors (eg, sacubitril) prevent the degradation of ANP and BNP, enhancing their beneficial effects in heart failure.
ANP and BNP
increase GFR, increase diuresis, renin inhibition, decrease aldo, vasodilator, increase cap permeability
sarcomere is defined as the distance between two Z lines. Thin (actin) filaments in the I band are bound to structural proteins at the Z line, whereas thick (myosin) filaments in the A band are bound to structural proteins at the M line.
Mycobacterial resistance to isoniazid (INH) is primarily mediated by
reductions in the catalase-peroxidase enzyme or through genetic modification of the INH binding site on the mycolic acid synthesis enzyme.
what happens in postpartum thyroiditis
within 12 months of pregnancy and is characterized by autoimmune destruction of thyroid follicles. It typically has a hyperthyroid phase due to release of preformed thyroid hormone, followed by a hypothyroid phase due to depletion of thyroid hormone stores and eventual return to a euthyroid state. Thyroid metabolic activity during the hyperthyroid phase is suppressed, and glandular blood flow and radioiodine uptake are low.
whats hawthorn effect
is the tendency of study subjects to change their behavior as a result of their awareness that they are being studied.
antisocial not diagnosed in individuals under 18!!!
XL recessive pattern
In X-linked recessive inheritance 1) affected males will always produce unaffected sons and carrier daughters, and 2) carrier females have a 50% chance of producing affected sons and carrier daughters. G6PD deficiency follows this inheritance pattern and causes acute hemolytic anemia in response to oxidant drugs.
what encourages more blood to RA
Paradoxical embolization, or passage of a thromboembolism from the venous to the arterial circulation, most commonly occurs through a patent foramen ovale (PFO). A PFO is a one-way tissue valve in the atrial septum that opens only when right exceeds left atrial pressure; venous return to the right atrium increases during the release (ie, relaxation) phase of the Valsalva maneuver and encourages the PFO to open.
Xlinked dom
In X-linked dominant inheritance, affected individuals have at least 1 parent (of either sex) that is also affected. An affected male will always produce affected daughters, but none of his sons will be affected.
what is pierre robin
Pierre Robin is characterized as a sequence because the primary defect (hypoplasia of the mandibular prominence) leads to a cascade of further malformations (ie, micrognathia, posteriorly displaced tongue, U-shaped cleft palate).
what is retinoblastoma associated with
Retinoblastoma is associated with inactivating mutations of the RB1 tumor suppressor gene, which normally restricts cells from passing the G1/S checkpoint until the cell is ready to divide. Impaired function of the Rb protein allows unrestricted progression through the G1/S checkpoint, leading to uncontrolled cell division.
porphyrin synthesis
Enzyme deficiencies of the early steps in porphyrin synthesis cause neuropsychiatric manifestations without photosensitivity, whereas late step derangements lead to photosensitivity. Photosensitivity manifests as vesicle and blister formation on sun-exposed areas as well as edema, pruritus, pain, and erythema.
IVC anatomy
inferior vena cava (IVC) courses through the abdomen and inferior thorax in a location anterior to the right half of the vertebral bodies. The renal veins join the IVC at the level of L1/L2, and the common iliac veins merge to become the IVC at the level of L5. IVC filters are placed in patients with deep venous thrombosis who have contraindications to anticoagulation therapy.
intraductal papilloma
characterized by epithelial and myoepithelial cells lining fibrovascular cores in a cyst wall or duct. It is the most common cause of bloody nipple discharge and typically presents without breast masses or skin changes.
pagets of breasts
characterized by epithelial and myoepithelial cells lining fibrovascular cores in a cyst wall or duct. It is the most common cause of bloody nipple discharge and typically presents without breast masses or skin changes.
Derivatives of the third pharyngeal pouch
include the thymus and inferior parathyroid glands. Disrupted development of the third pharyngeal pouch (eg, DiGeorge syndrome) leads to thymic hypoplasia/aplasia with impaired T-cell development and immunodeficiency.
1st pouch/cleft
1st Eustachian tubeTympanic cavityMastoid air cells External auditory meatusTympanic membrane 1st cleft: preauricular cyst/fistula
2nd pouch /cleft
2nd Palatine tonsilSupratonsillar fossa Cervical sinus (obliterated by development of 2nd arch) 2nd cleft: persistent cervical sinus/fistula2nd pouch: cleft palate
3rd pouch / cleft
Cervical sinus (obliterated by development of 2nd arch) 2nd cleft: persistent cervical sinus/fistula2nd pouch: cleft palate
3rd & 4th pouches**: 22q11 microdeletion syndrome (eg, DiGeorge, velocardiofacial)
4th pouch/cleft
4th Dorsal wings: superior parathyroid glandsVentral wings: parafollicular C cells of thyroid
cervical sinus/fistula2nd pouch: cleft palate
3rd & 4th pouches**: 22q11 microdeletion syndrome (eg, DiGeorge, velocardiofacial)
V3 exits skull through what
The third (mandibular) branch of the trigeminal nerve exits the skull through the foramen ovale and innervates the muscles of mastication, including the masseter, the medial and lateral pterygoids, and the temporalis muscles.
optic canal
CNII opthalmic artery, central retinal vein
superior orbital fissure
CN 3, 4, V1, V5 opthalmic vein, sympathetic fibers
foramen rotundumm
CNV2
spinosum
middle meningeal a and vein
internal acoustic meatus
CN VII, VIII
jugular
CN 9, 10, 11, jugular vein
hypoglossal
CN 12
foramen magnum
spinal roots of XI, brain stem, vertebral a.
ankylosing spondylitis
The pathogenesis of ankylosing spondylitis likely originates with defects in the intestinal mucosal barrier and exposure to the gut microbiome that lead to an enhanced IL-17–mediated inflammatory response. IL-17 stimulates production of additional inflammatory factors, primarily tumor necrosis factor-alpha and prostaglandins, which have synergistic proinflammatory effects and induce bony erosions and abnormal bone regrowth in the skeleton. elevated esr and crp
IL-2 and interferon gamma
have broad immune functions, including activation of the response against viruses and mycobacteria. Both cytokines inhibit Th17 cell differentiation and do not have a significant role in the pathogenesis of AS.
IL 4
IL-4 is important in the differentiation of naïve Th cells into the Th2 subset, alternative macrophage activation (M2 type), and IgE production. It may also have a protective role in AS by limiting IL-17 production by Th1 and Th17 cells. Interferon alpha is involved primarily in antiviral activity and is not a significant factor in the pathogenesis of AS.
IL 5
IL-5 induces B-cell growth, IgA production, and eosinophil activity. IL-5 and IL-4 are important in the etiology of certain allergic disorders (eg, allergic rhinitis, asthma), but do not contribute significantly to AS.
IL 10
IL-10 is an antiinflammatory cytokine. Transforming growth factor-beta has antiinflammatory and profibrotic effects. These cytokines have only a minor effect in AS.
GLUT 4
Glucose uptake in skeletal muscle occurs primarily via glucose transporter (GLUT) 4. Muscle contraction and insulin induce translocation of GLUT4 to the cell surface, increasing glucose uptake during exercise and the fed state, respectively. Over time, regular exercise causes increased expression of GLUT4, leading to increased skeletal muscle glucose uptake at any given insulin level and therefore lower blood glucose levels.
GLUT 2
GLUT2 is found primarily in the liver and pancreatic beta cells, where it facilitates insulin-independent glucose uptake. It is not expressed significantly in muscle or translocated in response to muscle contraction.
Ehlers-Danlos syndrome (EDS) is
a heritable connective tissue disease associated with abnormal collagen formation. EDS usually manifests clinically as overflexible (hypermobile) joints, overelastic (hyperelastic) skin, and fragile tissue susceptible to bruising, wounding, and hemarthrosis
Elastin, a fibrous protein in the connective tissue,
Elastin, a fibrous protein in the connective tissue, is named for the elastic properties it imparts to skin, blood vessels, and lung alveoli. Elastin fibers can be stretched to several times their original length but will recoil when the stretching forces are withdrawn. Elastin is synthesized from the polypeptide precursor tropoelastin.
receptors of urinary bladder
Urgency incontinence, or overactive bladder, is caused by uninhibited bladder contractions (detrusor instability) that results in a sudden urge to void followed by an involuntary loss of urine. Treatment with beta-3 adrenergic receptor activation (eg, mirabegron) relaxes the detrusor muscle, promotes urine storage, and decreases incontinent episodes.
Beta-3 receptor agonists (eg, mirabegron),
which causes detrusor smooth muscle relaxation, allowincreased urine storageand decreaseincontinent episodes. Because they are selective receptor agonists, they are often better tolerated with fewer systemic adverse effects.
Antimuscarinics (eg, oxybutynin), which block
M3 receptors at the bladder, prevent detrusor contractions. However, antimuscarinics often act on several types of muscarinic receptors and should be used with caution, especially in elderly patients and those with cognitive impairment due to medication adverse effects (eg, decreased cognition, blurred vision, drowsiness).
internal sphincter receptors
a1
external sphincter receptors
Nm receptors
tach sachs
Tay-Sachs disease is an autosomal recessive disorder caused by β-hexosaminidase A deficiency, which results in GM2 ganglioside accumulation in neuronal lysosomes. Key clinical features include progressive neurodegeneration (eg, developmental regression), an exaggerated startle reflex, and a cherry-red macular spot.
Krabbe disease
(galactocerebroside accumulation) is a lysosomal storage disease that causes progressive neurodegeneration. However, affected infants have optic atrophy, which is visualized as optic nerve pallor rather than a bright red fovea.
Gaucher
is a lysosomal storage disorder in which glucocerebroside accumulation results in bone pain, hepatosplenomegaly, and bone marrow suppression (eg, anemia, thrombocytopenia).
Mucopolysaccharidoses (eg, Hurler syndrome, Hunter syndrome)
are lysosomal storage disorders characterized by the build-up of glycosaminoglycans such as heparan and dermatan sulfate. Patients have neurocognitive decline, but coarse facial features and hepatosplenomegaly are also expected. Although Hurler syndrome is associated with corneal clouding, neither mucopolysaccharidosis causes a cherry-red macula.
Niemann Pick
Neurodegeneration and a cherry-red macular spot occur in Niemann-Pick disease, which is characterized by sphingomyelin accumulation. However, hepatosplenomegaly would be present
hyperplasia in cells for renal artery stenosis
Neurodegeneration and a cherry-red macular spot occur in Niemann-Pick disease, which is characterized by sphingomyelin accumulation. However, hepatosplenomegaly would be present
Macula densa
cells are tall, narrow cells located in the distal tubule that monitor salt content and tubular flow rate. This information is transmitted to nearby JG cells that are located mainly in the wall of the afferent arteriole. JG cells are modified smooth muscle cells with renin-containing zymogen granules.
ADH, urine sodium, total body volume in ascites?
Portal hypertension in cirrhosis leads to vasodilation and decreased systemic perfusion pressure, which causes antidiuretic hormone release and activation of the renin-angiotensin-aldosterone system, promoting sodium and water retention. However, due to resistance to splanchnic flow, low oncotic pressure, and hyperdynamic circulation, the fluid is third-spaced into the extravascular compartments (eg, ascites). Therefore, despite increased total body volume, patients with cirrhosis remain intravascularly volume depleted.
JAK2/STAT
Chronic kidney disease is commonly associated with normocytic anemia due to reduced production of erythropoietin by the kidneys. Erythropoietin signal transduction is primarily mediated by the Janus kinase 2/signal transducer and activator of transcription (JAK2/STAT) signaling pathway, which promotes erythrocyte precursor survival and differentiation.
Alveolar fluid contains proteases (eg, elastases) that are derived from alveolar macrophages and infiltrating neutrophils. These proteases can cause destruction of terminal lung parenchyma (eg, emphysema) when secreted in excess (or if left unchecked by deficient antiprotease activity).
labs of different anemias
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potassium and DKA
Most patients with diabetic ketoacidosis have normal to increased serum potassium levels despite a total body potassium deficit. Replacement of potassium is a crucial step in the management of patients with diabetic ketoacidosis.
