Uworld 7 Flashcards
Poststreptococcal glomerulonephritis occurs after exposure to?
Strains of group A streptococcus that produce nephritogenic antigens; antigen-antibody complexes deposit on the glomerular basement membrane and activate the alternate complement pathway.
What is seen on IF for poststreptococcal glomerulonephritis?
Granular deposits of IgG, IgM, and C3 in the basement membranes and mesangium.
When does intestinal malrotation occur?
When the midgut undergoes incomplete counterclockwise rotation during embryologic development
How does intestinal malrotation present?
In the neonatal period with biliois emesis due to extrinsic duodenal compression by Ladd bands or due to midgut volvulus with intestinal ischemia.
How does antibiotics alter the normal vaginal flora?
Antibiotics use alters the balance of normal vaginal flora (eg, decrease the number of gram+ lactobacilli and facilitates Candida overgrowth.
Patients can develop vulvovaginal candidiasis, which presents with vulvar/vaginal/perianal pruiritis; erythema; and a thick, white vaginal discharge.
Pudendal nerve injury can occur due to?
Excessive stress on the pelvic floor during labor and delivery (eg, prolonged second stage).
Nerve injury leads to denervation and weakness of the perineal musculature (eg, external anal sphincter), which can present as new-onset fecal incontinence.
Homecystinuria is most commonly caused by?
Cystathionine synthase deficiency.
Affected individuals have marfanoid habitus, ectopia lentis, and developmental delay.
What is the significant morbidity and mortality for homocystinuria?
Due primarily to thromboembolism.
Many patients with homocystinuria respond dramatically to pyridoxine (vitamin B6) supplementation.
How is GFR estimated in common practice?
GFR is estimated using creatinine clearance.
However, creatinine is actively secreted by the proximal tubules, so uncorrected creatinine clearance overestimates the GFR by approximately 10%-20%.
What is atrophy?
A cellular adaptation characterized by a decrease in cell size and number, leading to decreased organ size.
Pathologic atrophy physical workload, loss of innervation, decreased blood supply, inadequate nutrition, absent endocrine stimulation, aging, and mechanical pressure.
Testosterone replacement therapy is indicated for men with?
Symptomatic hypogonadism.
It is associated with an increase in serum prostate-specific antigen and may raise the risk of prostate cancer.
In addition, testosterone therapy can cause erythrocytosis (leading to thromboembolism), and hematocrit should be regularly monitored.
What causes the green discoloration of pus/sputum?
Green discoloration of pus/sputum seem during common bacterial infections is due to the presence of myeloperoxidaase, a blue-green heme-based enzymes that is released from neutrophil azurophilic granules and forms hypochlorous acid (bleach).
What is the MOA of glucocorticoids?
Inhibit transcription of proinflammatory mediators and promote apoptosis of eosinophils, T cells, and monocytes
What is stimulant withdrawal is characterized by?
Dysphoric mood, fatigue, hypersomnia, hyperplasia, and vivid dreams.
Stimulant withdrawal is not associated with significant findings on PE.
What steps are required before finalized mRNA molecules?
When mRNA is first transcribed from DNA, it is an unprocessed form called pre-mRNA or heterogeneous nuclear mRNA (hnRNA).
Several processing steps are required before finalized mRNA molecules can leave the nucleus, including 5’-capping, poly A tail addition, and intron splicing.
Cytoplasmic P bodies an important role in mRNA translation regulation and mRNA degradation.
Name the seronegative spondyloarthropathies associated with inflammatory bowel disease
Ankylosing spondylitis, reactive arthritis, psoriatic arthritis, and arthritis.
Individuals expressing HLA B27 (a specific HLA class I molecule) are at increased risk for seronegative spondylarthropathies.
The chemotherapeutic effet of methotrexate is overcome by?
Overcome by N5-formyl-tetrahydrofolate (folinic acid, leucovorin) supplementation
Methotrexate and 5-FU both inhibit what?
Inhibit thymidylate formation
What are the primary mediators of disease in chronic obstructive pulmonary disease?
Neutrophils, macrophages, and CD8+T lymphocytes.
They secrete enzymes and proteases that cause and perpetuate both the alveolar destruction of emphysema and the mucus hypersecretion found in chronic bronchitis.
Midshaft fractures of the humerus risk injury to what?
The deep brachial (profunda brachii) artery and radial nerve run together along the posterior aspect of the humerus
V3 Mandibular branch of trigeminal nerve innervates what muscles?
The muscles of mastication: masseter, the medial and lateral pterygoids, and the temporalis muscle.
V3 mandibular branch of trigemal nerve exits the skull through?
Foramen ovale
Classic triad for acute bacterial meningitis? evaluation?
fever, stiff neck, and altered mentation
Evaluation requires prompt blood cultures, empiric antibiotics, and lumbar puncture with cerebrospinal fluid analysis
What is the mechanism of reperfusion injury?
Reperfusion injury is thought to occur secondary to oxygen free radical generation, mitochondrial damage, and inflammation.
IV drug users are at increased risk for what?
Increased risk of tricupsid valve endocarditis, which can cause multiple septic pulmonary infarcts due to embolization of tricuspid valve vegetation fragments.
Pulmonary infarcts are typically hemorrhagic (red) and wedge-shaped in the periphery of the lung
Amyotrophic lateral sclerosis can cause?
Causes degeneration of both upper and lower motor neurons and can result in bulbar and skeletal muscle weakness.
Denervation atrophy can affect the diaphragm and contribute to respiratory failure.
What is fluorescence in situ hybridization (FISH) used for?
FISH can identify specific chromosomal translocations, duplications, or deletions using a single-stranded, complementary DNA segment that is tagged with a radiotracer.
FISH is rapid, highly sensitive and specific, and can be used on tissues with low mitotic rates.
However, the targeted chromosomal abnormality must be somewhat large in order to be identified.
What happens to the O2 and Co2 levels in the body during exercise?
During physical exercise, there is increased skeletal muscle CO2 production that increases the CO2 content of venous blood.
Arterial O2 and CO2 content remains constant via increases in alveolar ventilation and gas exchange efficiency.
Venous O2 content remains constant or is decreased due to increased O2 extraction by the tissues that matches or exceeds the rate of oxygen delivery (ie, O2 consumption during exercise is limited by cardiac output)
Overuse/abuse of loop diuretics (eg, furosemide) will show what on electrolyte panel?
Hypokalemic, hypochloremic metabolic alkalosis.
Urine electrolytes findings depend on how recently the diuretic was last ingested, increased urine Na, Cl and K are expected with recent ingestion
What is MOA behind cough secondary to ACE inhibitor therapy?
Cough secondary to ACE inhibitor therapy is characterized as dry, nonproductive, and persistent.
The mechanism behind ACE inhibitor induced cough is accumulation of bradykinin, substance P, or prostaglandins.
How does allogeneic hematopoietic stem cell grafts initiate graft versus host disease?
Allogeneic hematopoietic stem cell grafts normally induce donor CD3+T cells that can initiate graft versus host disease, a widespread inflammatory response that can damage multiple organs.
Depletion of donor CD3+T cells prior to transplant decreased the risk of GVHD but also decreased the beneficial graft versus tumor effect, increasing the likelihood of cancer relapse.
What are quick clinical tests to assess attention and concentration?
Counting down from 100 by intervals of 3 or 7, reciting the months of the year in reverse order, and spelling “world” backwards.
Drugs that should be used with caution in geriatric patients
Anticholinergics (eg first-gen antihistamines), centrally acting alpha-2 agonists, tricyclic antidepressants, benzodiazepines (and other sedating meds), antipsychotics, many antiarrhythmics (eg, digoxin), and skeletal muscle relaxants.
Injury to the C5 and C6 nerve roots causes what?
Erb-Duchenne palsy: waiter’s tip posture. The affected arm may have decreased/absent Moro and biceps reflexes; grasp reflex remains intact.
What is acute respiratory distress syndrome?
A severe inflammatory reaction that occurs in the lungs and results in hypoxemia and noncardiogenic pulmonary edema.
Pulmonary injury leads to an inflammatory response resulting in breakdown of the capillary-alveolar barrier (created by type 1 pneumocytes and endothelial cells), increased capillary permeability, intraalveolar fluid accumulation, and hyaline membrane formation.
In patients with cirrhosis, hyperestrinism can cause?
gynecomastia, spider angiomata, loss of sexual hair, testicular atrophy and palmar erythema.
What is the greatest complication of a hookworm infection?
Hookworms are transmitted when human skin comes into contact with soil contaminated with human feces.
The larvae penetrate the skin, travel to the lungs, are coughed up, and then swallowed.
Adult hookworms live in the small intestine and feed on human blood. Therefore, chronic iron deficiency anemia (microcytic anemia) is the greatest complication.
What is the function of Inhibin B?
Inhibin B, produced by heat-sensitive Sertoli cells, is a physiologic inhibitor of FSH secretion.
In patients with cryptorchidism what happens to the levels of reproductive hormones?
atrophy of Sertoli cells results in decreased inhibin B, and in turn will elevate FSH.
Leydig cell function is not significantly affected, so testosterone and LH are typically normal.
What is primary adrenal insufficiency?
Characterized by weight loss, abdominal pain, fatigue, and hyperpigmentation.
Physiologic stress in patients with PAI can trigger acute adrenal crisis (eg fever, shock, mental status changes)
