5/19 UWORLD TEST 1 Flashcards
Osteosarcoma
Bone tumor most often associated with Paget’s disease
Arising in femur, tibia, humerus, other bones
Destruction of normal trabecular bone pattern, mixed radiodense and radiolucent areas, periosteal new bone formation, lifting of the cortex, Codman’s triangle
Adjacent soft tissue usually demonstrates ossification in a “sunburst” pattern
Acetylcholine like muscarinic agonists
Cause smooth muscle contraction
Potentiated by physostigmine
Inhibited by atropine
Germline mosaicism
Presence of multiple, genetically different gamete cell lines
Should be considered when a genetic mutation is identified in the offspring but not in the parents
Note* somatic mutations cannot be passed on to offspring!!
Interleukin-2
Is exclusively produced by T lymphocytes and functions to stimulate the growth and differentiation of T cells, B cells, NK cells, and macrophages
Molluscum contagiosum
Characterized by umbilicated, flesh colored papules on the skin and mucous membranes
It is caused by a poxvirus, which appears in pathologic specimens as eosinophilic cytoplasmic inclusions (molluscum bodies)
Anterior and posterior dislocations at the knee joint
Injury to the popliteal artery is the primary concern
This vessel is rigidly fixed proximal and distal to the knee joint by the adductor magnus and soleus muscles, respectively
Sublimation
A mature defense mechanism in which a person channels unacceptable thoughts or impulses into socially acceptable behavior
Heminephrectomy
Results in compensatory hyperfiltration and hypertrophy of the nephrons in the remaining kidney.
Post-nephrectomy, the total GFR increases from 50% to approximately 80% of its original value within several weeks
Acute intermittent porphyria
Deficiency of porphobilinogen deaminase
Intermittent episodes of abdominal pain with neurological manifestations following exposure to an offending medication
Urine from patient during attacks will classically darken when exposed to sunlight
Skin photosensitivity is characteristically absent
Metabolic derangements associated with DKA
Metabolic acidosis, ketonemia, hyperglycemia, hyperkalemia, hyponatremia
Hyperammonemia can also be observed due to muscle degradation
Complete androgen insensitivity syndrome
Rare, x-linked disorder
“Testicular feminization”
46, XY karyotype with a female phenotype
Mutated testosterone receptors throughout the body that are resistant to androgens
Serum testosterone are in normal range for males, LH is high, FSH is normal
Peripherally converted to estradiol, results in breast development
Vagina ends abruptly in a blind pouch (Mullerian structures are absent) with external female genetalia
Intraventricular hemorrhage
AKA germinal matrix hemorrhage (in utero)
Due to germinal matrix fragility
Amiodarone-induced interstitial pneumonitis
Slowly progressive dyspnea, fever, cough, patchy interstitial infiltration on radiograph > inflammation and fibrosis in the pulmonary interstitium
Usually reversible with a reduction in dose or discontinuation of the drug
Misoprostol
PGE1 analog
Binds to plasma membrane prsotaglandin receptors
In the upper GI tract, misoprostol stimulates gastric epithelial cell mucus production and appears to decrease parietal cell acid secretion
Head and neck cancers
Vast majority are squamous cell carcinomas
Strongly associated with the use of tobacco and alcohol
Tend to develop in the oral cavity- ventral tongue, floor of mouth, lower lip, soft palate, gingiva = MC sites of origin
Often infiltrates adjacent tissue, may eventually metastasize locally to cervical lymph nodes or distally to mediastinal lymph nodes, lungs, liver, bones
Albright hereditary osteodystrophy
Pseudohypoparathyroidism
Short stature, and short metacarpal and metatarsal bones
Allelic heterogeneity
Different mutations at the same genetic locus cause similar phenotypes
Ex. three different mutations can cause B-thalassemia
Note:
Genetic heterogeneity=mutations of different genes cause similar phenotypes
Phenotypic heterogeneity= mutations in the same gene result in markedly different phenotypes
Hemochromatosis
AR disease
Excessive GI absorption of iron
Common manifestations: liver disease with hepatomegaly, diabetes mellitus secondary to pancreatic islet destruction, arthropathy, pituitary hormone deficiencies, hyperpigmentation, cardiomyopathy
Manifests > 40 years
Cirrhosis
Causes portal HTN due to distortion of the hepatic vascular bed; the increased pressures in the portal venous system can cause splenic vein hypertension and splenomegaly
Achondroplasia
Gain of function point mutation of the fibroblast growth factor receptor 3 (FGFR3) gene
Presents with proximal limb (humeral/femoral) shortening, midface hypoplasia, frontal bossing, macrocephaly, shortened digits with a space between the 3rd and 4th digits
Proteins destined for the RER possess
Hydrophobic, N-terminal peptide signal sequences that identify the as such
Removal of these sequences would cause inappropriate protein accumulation in the cytosol
Maple syrup urine disease
Defect in the branched chain alpha-keto acid dehydrogenase complex, which is responsible for the catabolism of the branched chain alpha-amino acids leucine, valine, and isoleucine
This enzyme complex requires thiamine (B1) as a coenzyme
Alpha-thalassemia
Classic peripheral smear of hypochromic, microcytic cells
Offspring are at risk for absent alpha globin production- the most severe form of alpha thalassemia, which leads to hemoglobin Barts accumulation and death in utero from hydrops fetalis (anasarca, ascites, effusions)
Androgen-binding protein (ABP)
Synthesized in the Sertoli cells of the seminiferous epithelium and secreted into the seminiferous tubule lumen
ABP maintains the high local concentration of testosterone necessary for normal sperm production and maturation
Hyperhidrosis
Excessive sweating due to sympathetic hyperacitvity
Sympathetic postganglionic cholinergic neurons innervate eccrine and apocrine sweat glands
Rx: systemic anticholinergic meds (oxybutynin), local anticholinergic injectable meds (botulinum toxin), surgical sympathectomy (for axilla = ablation of thoracic sympathetic trunk)
Red safranin O stain
Stain cartilage, mast cell granules, and mucin red
Cartilage on histology
Presence of cells surrounded by a glassy matrix of ground substance and collagen
Predominant collagen found in hyaline cartilage is type II collagen
Idiopathic pulmonary arterial hypertension (IPAH)
Increased pulmonary artery pressure and right ventricular failure
Starts with injury to the pulmonary endothelium secondary to an idiopathic mechanism or a known medical condition (cardiac defects, collagen vascular disease, PE)
Ischemic colitis
Common cause of lower GI hemorrhage in eldely
Crampy abd pain, tenderness to palpation, bloody stool
Weak lower extremity pulses indicate extensive atherosclerosis
Histology: mucosal hemorrhage, ecchymoses, patchy necrosis, eventually leading to thickening of bowel, edema. Transmural infarction can result bowel perforation
Ras
GTP binding, signal-transducing oncoprotein
Treatment for carcinoid tumor
Octreotide
Somatostatin analog that functions by inhibiting the release of bioactive peptides by the carcinoid tumor
Protein synthesis during apoptosis
Internal ribosome entry is an alternative method used by apoptotic cells whereby a distinct nucleotide sequence allows translation to begin in the middle of mRNA
Thiazolidinediones (pioglitazone, rosiglitazone)
Peroxisome proliferator-activated receptor Y (PPAR-y) agonists that increase transcription of insulin-responsive genes.
Thiazolidinediones exert their glucose lowering effects by decreasing insulin resistance
Crohn disease
Chronic, idiopathic, inflammatory condition
Most frequently involves the TERMINAL ILEUM
Abdominal pain, diarrhea, low-grade fever, aphthous ulcers, of the mouth and perianal disease (fissures, abscesses)
Cimetidine effects on Warfarin
Slows the metabolism of warfarin, resulting in a gradual increase of the prothrombin time over a period of several days
Hepatic encephalopathy Rx
Lactulose acidifies the contents of the GI tract, converting NH3 into NH4+
Osteomalacia
Decreased mineralization of newly deposited osteoid
Presents with bone pain, muscle weakness, increased fracture risk
Most often caused by Vit D deficiency and the resulting hypophosphatemia
Atherosclerotic plaques
Eccentric intimal thickening with a fibrous cap, smooth muscle proliferation, local inflammatory infiltrate, and a lipid filled core
Exertional leg pain, dermal atrophy, arterial ulcers
Li-Fraumeni syndrome
AD, early onset malignancies (breast cancer, bone and soft tissue sarcomas, adrenocortical carcinoma, brain tumors)
Single germline mutation in p53 tumor suppressor gene (present in every cell in patient’s body)
A second hit leads to unchecked proliferation of mutated cells and carcinogenesis
Coccidioides immitis
Dimorphic soil fungus endemic to San Joaquin Valley, southwest United States, Mexico, and South America.
It most commonly causes asymptomatic infection or mild pneumonia
Rarely it may cause formation of a thin walled cavity in the lung leading to hemoptysis in addition to fever and cough
Rash and symmetric arthralgias
Intellectualization
Use of excessive thinking to avoid painful emotions or fears; particularly common in patients recently diagnosed with serious medical illnesses
Atrial septal defect
Widely split and fixed S2
Less common symptoms of anemia
Glossal pain, dry mouth, atrophy of the tongue papillae, alopecia, pagophagia
Reactive arthritis
Acute oligoarthritis of the appendicular skeleton, often with conjunctivitis and urethritis
Caused by deposition of immune complexes, usually from genitourinary or GI infection
CANT SEE, CANT PEE, CANT CLIMB A TREE
Prader-Willi Syndrome
Neonatal hypotonia, extremem hyperphagia, progressive obesity, hypogonadism, small hands and feet
Microdeletions involving the paternal chromosome 15q11-13 or maternal uniparental disomy
PCOS
Elevated ovarian androgen levels (testosterone) stimulate development of small ovarian follicles and prevent the formation of a single dominant follicle
Leads of ovulatory dysfunction and the characteristic polycystic pathology of polycystic ovary syndrome
Pernicious anemia
Autoimmune destruction of gastric mucosa
Production of gastric acid is diminished, leading to compensatory increase in gastrin release
Secretion of gastric intrinsic factor is also lost, leading to Vitamin B12 deficiency
Varicoceles
Dilations of the spermatic vein pampiniform plexus that enlarge with standing and regress with lying down
Patients may be asymptomatic or experience aching pain relieved with recumbency, testicular atrophy, or reduced fertility
Does not transilluminate light
Leuprolide
Continuous administration of GnRH analog inhibits secretion of FSH and LH
In patients with prostate cancer, this decreases testosterone production and can slow progression of the disease
DiGeorge Syndrome
Facial abnormalities, thymic and parathyroid aplasia, cardiac and great vessel defects. Maldevelopment of the truncus arteriosus is common in utero, resulting in persistent truncus arteriosis, tetralogy of Fallot, or interrupted aortic arch
Gaucher disease
Most common lysosomal storage disease
B-glucocerebrosidase deficiency, and glucocerebroside accumulation
Hepatosplenomegaly, pancytopenia, skeletal destruction, which can lead to severe bone pain and avascular necrosis
Transformation
Process by which bacteria take up naked DNA from their environment and incorporate it into their genomes
(DNase degrades naked DNA in the culture media, preventing transformation)
Homeobox (HOX) genes
Encode transcription factors that guide the pattern of embryo development along the rostro-caudal, limb and genital axes
Mutations in HOXA13 can cause hand-foot-genital syndrome, a rare dominantly inherited syndrome marked by distal limb defects including hypoplastic first digits and genitourinary malformations
