Uworld36 Flashcards
What is echinococcus granulosus?
the most common cause of hydatid cysts. Spilling of cyst contents can cause anaphylactic shock.
Surgical manipulation should be performed with caution.
What is associated with EBV mononucleosis?
Epstein Barr virus causes infectious mononucleosis in teenagers and young adults. It is also associated with Burkitt lymphoma and nasopharyngeal carcinoma
Erythromycin stimulates upper gastrointestinal motility by?
acting as an agonist on motillin receptors in the muscularis externa.
Therefore, it can be used to treat gastroparesis (ie, delayed gastric emptying), a condition that frequently occurs in patients with long standing diabetes mellitus.
What is axonal reaction?
The changes in the body of a neuron after the axon has been severed are called axonal reaction.
This process reflects an increased protein synthesis that facilitates axon repair.
Enlarged, rounded cells with peripherally located nuclei and dispersed finely granular Nissl substance are seen
What is use dependence in antiarrhythmics?
For class I antiarrhythmics, sodium channel binding strength is IC > IA> IB. Use dependence describes the phenomenon in which higher heart rates lead to increased sodium channel blockade due to cumulative blocking effects over multiple cardiac cycles.
Class IC demonstrate the most use dependence due to their slow dissociation from the receptor, and class IB drugs have the least use dependence as they rapidly dissociate.
Hyperacusis (increased sensitivity to sound) is an indication of?
damage to the facial nerve (CN VII) close to its origin from the brainstem.
What is Zollinger Ellison syndrome?
caused by gastrin-secreting tumors (gastrinomas) involving the small intestine or pancreas.
Patients typically have peptic ulcers (often beyond the duodenal bulb), abdominal pain/acid reflux, and diarrhea.
The condition is frequently associated with multiple neoplasia type 1
What coordinates normal respiratory drive?
The pontine and medullary respiratory centers coordinate normal respiratory drive.
Immaturity of these central respiratory centers causes apnea of prematurity, which is common in extremely preterm newborns.
What is lichen planus?
an immune mediated condition that presents with pruritic, pink papules and plaques, often with lacy, scaly, white markings (Wickham striae).
The lesions typically occur on the flexural surfaces of the wrists and ankles but can also involve the nails, oral mucous membranes, and genitalia.
What is seen in chronic rejection in lung transplants?
Chronic rejection is a major problem in lung transplant recipients; it affects small airways, causing bronchiolitis obliterans. It is characterized by lymphocytic inflammation, fibrosis, and destruction of the bronchioles
What are psychogenic causes of erectile dysfunction?
performance anxiety, depression, sexual trauma, relationship problems, and stress. Important clues include sudden onset and normal noctural erections
Melanoma stains which markers
S-100, HMB-45, MART-1
What is autosomal dominant (adult) polycystic kidney disease?
caused by mutations in the polycystin genes (PKD1, PKD2), which result in cystic enlargement of the kidneys and progressive renal dysfunction.
CF: hypertension, abdominal/flank pain, and gross hematuria, extrarenal manifestations include liver cysts and intracranial aneurysms
What is suppression?
mature defense mechanism involving a conscious choice not to dwell on a particular thought or feeling
What are the most effective lipid lowering drugs?
Although low HDL concentration is associated with increased cardiovascular risk, the use of medications to raise HDL levels does not improve cardiovascular outcomes.
HMG-CoA reductase inhibitors (statins) lower total cholesterol and LDL levels. Statins are the most effective lipid lowering drugs for primary and secondary prevention of cardiovascular events, regardless of baseline lipid levels
function of thoracic duct
The thoracic duct carries lymph from most of the body and drains into the junction between the left subclavian and jugular veins.
Although most commonly injured in thoracic procedures, it can also be injured in neck procedures where it travels through the neck. injury may result in a chylothorax.
What causes lung abscess?
Lung abscess is most often due to aspiration of anaerobic oral bacteria as Peptostreptococcus, Prevotella, Bacteroides, and Fusobacterium species.
Risk factors: conditions that increase aspiration risk, such as alcholism, drug abuse, seizure disorders, previous stroke and dementia
Helicobacter causes what in an acute infection versus chronic?
Acute H pylori infection causes nonatrophic antral gastritis and an increased risk for duodenal ulcers
Chronic infection: patchy, multifocal, atrophic gastritis with loss of parietal cells and G cells in the gastric body; this is associated with decreased acid secretion and an increased risk of gastric ulcers, gastric adenocarcinoma, and MALT lymphoma
Cause of uterine leiomyomas (fibroids)
Fibroids are common, benign tumors arising from the uterine myometrium that occur due to monoclonal proliferation of myocytes and fibroblasts
What is seen in head and neck squamous cell carcinoma?
is likely in a patient with cervical adenopathy and a base of tongue mass, especially with a history of tobacco use.
Classic histo: intercellular bridges and keratin pearls.
Elevated blood glucose induces the release of?
reactive oxygen species and proinflammatory cytokines from neutrophils while inhibiting the production of anti-inflammatory cytokines (IL-10) and growth factors needed for fibroblast proliferation and reepithelialization in a healing wound.
As a result, patients with uncontrolled diabetes frequently have nonhealing wounds with evidence of ongoing inflammation
What are the signs of uncal herniation?
Uncal herniation is a possible complication of an expanding ipsilateral mass lesion (hemorrhage, tumor).
The first sign of uncal herniation is a fixed, dilated pupil on the side of the lesion. Contralateral or ipsilateral hemiparesis and contralateral homonymous hemianopsia with macular sparing may also occur
What is seen in the cardiac myocyte action potential?
consists of rapid depolarization (phase 0), initial rapid repolarization (phase 1), plateau (phase 2), late rapid repolarization (phase 3), and resting potential (phase 4).
The action potential is associated with increased membrane permeability to Na and Ca and decreased permeability to K
What is the relationship of confidence interval (CI) and RR?
A confidence interval that includes the null value for an RR (ie, RR=1) is not statistically significant, and a CI that excludes the null value (RR=1) is statistically significant
What does the different measurements of RR mean?
the relative risk (RR) is a measure of association:
RR < 1 = lower risk of disease in the exposed group relative to the nonexposured
RR = 1 = no association between exposure and disease
RR > 1 = greater risk of disease in the exposed group relative to the nonexposed
MOA of phencyclidine (PCP)
primarily an N-methyl-D-asparate antagonist, with lesser effects on the reuptake inhibition of biogenic amines and other receptors.
It can have dissociative and anesthetic effects but may also cause psychosis and severe agitation, leading to violent trauma. Ataxia horizontal and vertical nystagmus and memory loss can also be present
What is the leading cause of atypical pneumonia?
Mycoplasma pneumoniae.
Because this pathogen lacks a cell wall, it does not show up on gram stain and cannot be treated with beta lactam antibiotics.
Protein synthesis inhibitors (macrolides, tetracyclines) are the treatment of choice
What are the histologic findings of idiopathic pulmonary fibrosis?
are most prominent in the lung periphery and include a heterogenous mixture of chronic inflammation and patchy interstitial fibrosis, focal fibroblast proliferation, and formation of fibrotic cystic spaces in a honeycomb pattern
What is myasthenia gravis?
caused by autoantibodies against postsynaptic nicotinic acetylcholine receptors, leading to fewer functional receptors and fatigable muscle weakness.
Nondepolarizing neuromuscular blocking agents (vecuronium) are competitive antagonists of nicotinic receptors; because of the depletion of receptors, patients with MG are extremely sensitive to these agents
What is the effect of metformin in a patient with heart failure?
Heart failure leads to reduced liver and kidney perfusion, resulting in reduced drug clearance.
Metformin is excreted unchanged by the kidney; therefore, patients with significant renal insufficiency due to heart failure or other causes (chronic kidney disease) are at increased risk of toxicity (lactic acidosis)
What is multiple myeloma?
a plasma cell malignancy that replicates in the bone marrow and causes osteolytic bone lesions, bone destruction, hypercalcemia, and pathologic fractures.
Histopath: replacement of the normal bone marrow with plasma cells and plasmablasts
How is normal blood glucose maintained?
Normal blood glucose levels are maintained by the opposing effects of insulin and glucagon.
Glucagon stimulates hepatic glycogenolysis and gluconeogenesis, whereas insulin increases peripheral glucose uptake and inhibits lipolysis and ketoacid formation. Insulin also suppresses glucagon release
What tests are very high sensitivity for giant cell (temporal) arteritis?
Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).
What is seen in acute pancreatitis?
In acute pancreatitis, release of lipase and other digestive enzymes causes fat necrosis with precipitation of insoluble calcium salts (saponification), imparting a chalky white gross appearance.
Microscope: necrotic fat cells with calcium deposits are seen. In severe cases, fat necrosis can involve the mesentery, omentum, and other parts of the abdominal cavity
What is staphlococcal food poisoning mediated by?
by the ingestion of a preformed, heat stable enterotoxin that induces rapid onset (<6hours) nausea and vomiting.
Most cases arise due to improper food handling and storage. Common culprit foods include eggs, dairy, mayonnaise based salads
Acute cholecystitis is most often caused by?
gallstones obstructing the cystic duct. The diagnosis can be made by identifying signs of gallbladder inflammation (wall thickening, pericholecystic fluid) on ultrasound.
When ultrasound is inconclusive, nuclear medicine hepatobiliary scanning (cholescintigraphy) can be used to assess cystic duct patency and make the diagnosis
What is the Reid index?
hyperplasia of the submucosal bronchial glands is the major contributor to bronchial wall thickening in chronic bronchitis.
The Reid index is the ratio of the thickness of the submucosal bronchial glands to the thickness of the bronchial wall between the epithelial basement membrane and the bronchial cartilage
What is seen in a prolactinoma?
Pituitary tumors can present with headaches, bitemporal hemianopsia, and hypopitutariusm; the most common hormonally active (functional) adenomas are prolactin-secreting adenomas (prolactinomas).
Prolactinomas can cause galactorrhea and amenorrhea in women. In men, they often present with hypogonadism
Dermatome that supplies the anteromedial thigh and medial leg
L3 and L4
What enzymes require thiamine as a cofactor?
Several enzymes involved in glucose metabolism (pyruvate dehydrogenase, alpha ketoglutarate dehydrogenase) require thiamine as a cofactor.
The adminstration of glucose to thiamine-deficient patients (chronic alcohol use) can precipitate Wernicke encephalopathy (acute confusion, opththalmoplegia, ataxia) due to rapid thiamine consumption