Week 1 Flashcards
What is the major component of surfactant? Function?
Dipalmitoyl phosphatidylcholine (lecithin) Function is to decrease alveolar surface tension and prevent alveolar collapse
What causes cilia to be immotile in Kartageners syndrome?
Dynein arm defect
What is phosphatidylglycerol?
A compound measured in amniotic fluid to determine fetal lung maturity, used in conjunction with lecithin:sphingomyelin ratio
Adrenergic symptoms (heart palpitations, sweating, headaches) and high urine metanephrine indicate what? What is the treatment? SE of treatment?
Pheochromocytoma - tumor that releases EPI, NE, DA
Treatment incudes alpha adrenergic receptor antagonists
DOC is phenoxybenzamine - irreversible, nonselective alpha blocker
Blocking alpha receptors can lead to HYPOTENSION because vasoconstriction is impaired
Classic signs of increased intracranial pressure? Sign of uncal herniation? Treatment?
Coma, bradycardia, HTN, hyperventilation and papilladema
A single fixed and dilated pupil can be a sign of ipsilateral uncal herniation
The immediate treatment is intubation with hyperventilation, elevating the head of the bed to 30 degrees, and using osmotic diuretics such as mannitol
Why does hyperventilation help with increased ICP?
CO2 is a powerful vasodilator of cerebral blood vessels. Mechanical hyperventilation can lower CO2 and rapidly reduce ICP through vasoconstriction and a decrease in the volume of intracranial blood
What accounts for 40-50% of all inherited thrombophilias?
Factor V leiden mutation (increased risk of recurrent thrombotic events, including unusual locations like the mesenteric veins)
Von Willebrands deficiency causes…What is it due to?
Prolonged bleeding time (nose bleeds, prolonged bleeding after trauma or surgery, hematoma). The most common inherited bleeding disorder in the US. Due to improper or absent formation of vW fx, a protein that binds platelets to the endothelium during clot formation. This protein also carries fx VIII, an important component of the clotting cascade
Von Hippel-Lindau disease is characterized by,,,
abnormal blood vessel growth leading to angiomas and hemangioblastomas in the retina, brain, and spinal cord
Propylthiouracil (PTU) is a standard agent in the treatment of hyperthyroidism. What is its mechanism of action? What are the adverse effects?
Inhibits both the conversion of iodide to elemental iodine and the organification of iodine with tyrosine, therefore blocking the production of mono- and diiodotyrosine within thyroid follicular cells (thyroid is formed by combining iodine and a protein called thyroglobulin with the assistance of an enzyme called peroxidase, PTU inhibits iodine and peroxidase). PTU also acts peripherally to inhibit the conversion of T4 to T3 (the more active form).
Adverse effects include exfoliative skin rash (most common) and agranulocytosis (most severe but rare)
Scarlet fever is caused by…
S. pyogenes or group A strep. It is mediated by a pyrogenic exotoxin and causes fever and diffuse erythema/rash
What is Whipple’s disease? What does biopsy show?
Whipple’s disease is caused by an infection with Tropheryma whipplei (gram+, non-acid-fast, PAS + bacillus). Symptoms include athralgias, weight loss, diarrhea and abdominal pain. Biopsy shows accumulation of macrophages with brightly stained PAS+ intracellular material
What viruses are in the flaviviridae family?
Flavus = yellow. Primarily spread through arthropod vectors. Linear SS (+) RNA family with icosahedral capsids.
Yellow fever, West nile virus, Dengue fever, Hepatitis C, Japanese encephalitis
Vaginal bleeding in postmenopausal woman (55-65) should raise the concern for what? What is it associated with?
Endometrial cancer
Associated with the action of unopposed estrogen on the uterus such as nulliparity, obesity, early menarche, late menopause and exogenous estrogen use
*with hormonal replacement therapy, progesterone is administered along with estrogen to mitigate this effect
What is Tamoxifen? What is it used for? Risks?
Tamoxifen is a partial agonist at the estrogen receptor. It blocks estrogen from binding at receptors in the breast making it a useful therapy for breast cancer BUT activates receptors in the endometrium leading to endometrial hyperplasia and an increased risk of endometrial cancer. Would see painless vaginal bleeding in a postmenopausal woman.
Other adverse effects: increased bone density, hypercoagulability, hot flashes, night sweats and vaginal discharge
What are leiomyomas? What age group do they affect?
Benign soft tissue neoplasm. Commonly called uterine fibroids, they can cause irregular bleeding. Most occur in woman <40 years old, with regression occurring after menopause. Many are asymptomatic but clinical symptoms can include severe pelvic pain and heavy or irregular menstrual bleeding. Risk factors include AA race, early menarche, nulliparity, and a positive family history
Epigastric pain improving after eating is…
Duodenal ulcer (vs. pain increasing after meals with gastric ulcer)
Treatment of H. Pylori? (Triple therapy)
Omeprazole (PPI), clarithromycin, and either amoxicillin or metronidazole
Neurofibromatosis type 2 is inherited in what manner?
Caused by? What is type 2 associated with?
Autosomal dominant
Caused by a mutation in the NF2 gene on chromosome 22
Type 2 is associated with bilateral acoustic neuromas
Smudge cells are associated with what?
Chronic lymphocytic leukemia
Patients with CML have marked leukocytosis and a peripheral blood smear showing…
myeloid cells in various stage of development, from mature granulocytes to metamyelocytes to myelocytes
What is multiple myeloma? Hallmark symptoms?
Multiple myeloma is a cancer of plasma cells in which abnormal plasma cells multiply uncontrollably in the bone marrow and occasionally in other parts of the body
Hallmark symptoms: renal insufficiency, anemia, lytic bone lesions, and susceptibility to infection
Initial treatment for myasthenia gravis? What is used to test for MG?
Pyridostigmine (duration of 3-6 hours), an acetylcholinesterase inhibitor. Prolongs the effects of acetylcholine by competing for attachment to AChE. Thymectomy is first line treatment in patients with generalized myasthenia gravis
Edrophonium is a readily reversible AChE inhibitor used for dx. Duration of action is only 19 minutes and is thus impractical for treatment
What triggers release of catecholamines (epinephrine and norepinephrine) from the adrenal medulla? AKA how do you produce a situation in the lab that resembles pheochromocytoma HTN crisis
Direct stimulation by pre-ganglionic sympathetic neurons via acetylcholine. The adrenal medulla is a unique sympathetic neurotransmitter in that the nerves that supply it do not first synapse in other sympathetic ganglia. Presynaptic neurons typically use ACh as their NT. In this case the ACh binds to nicotinic ACh receptors in the adrenal medulla
Niemann-Pick disease typically presents with? What is the deficiency? What does the enzyme convert?
Hepatosplenomegaly and progressive widespread neurodegeneration
*cherry-red spot on the macula & foam cells (lipin-laden macrophages)
Deficiency of sphingomyelinase (converts sphingomyelin to cerebroside)
Lysosomal storage diseases are inherited?
AR except for Fabry which is XR
Which disease is deficient in Hexosaminidase A? What does this enzyme convert? How does the disease present?
Tay-Sachs
Converts ganglioside M2 to ganglioside M3
The disease presents with progressive neurodegeneration and developmental delay. Children become blind, deaf and unable to swallow.
*Cherry red spot on macular, TS distinguishable from Neiman-Pick by absence of hepatosplenomegaly
Gauchers disease: enzyme, presentation, light microscopy appearance
Enzyme deficient is B-Glucocerebrosidase (converts glucocerebroside to cerebroside)
Clinical manifestation includes hepatosplenomegaly, skeletal weakness and bone crises (aseptic necrosis of femur)
Macrophages appear as crumpled up paper on light microscopy and are known as Gaucher’s cells
Fabry disease: enzyme, build up and findings
Enzyme: a-galactosidase A (trihexoside to lactosyl cerebroside)
Accumulated substrate: ceramide trihexoside
Findings: Peripheral neuropathy of hands/feet, angiokeratomas (tiny painless papules), cardiovascular/renal disease
Krabbe’s disease: enzyme, build up and findings
Enzyme: Galactocerebrosidase (galactocerebroside to cerebroside)
Accumulated substrate: Galactocerebroside, psychosine
Findings: Normal at birth, 3-6 months; Peripheral neuropathy, developmental delay, optic atrophy, globoid cells
APL is associated with what translocation? What genes does this involve? Treatment?
t (15;17) - PML and retinoid acid receptor
Treatment with retinoic acid frequently leads to clinical remission
C-myc and immunoglobulin heavy chain locus translocation occurs between what chromosomes? What is the resulting disease?
t(8;14)
Burkitt’s lymphoma
Burkitt’s lymphoma - what is the translocation (genes and chromosome number)
t(8;14)
8 - c-myc
14 - immunoglobulin heavy chain locus
What virus is associated with congenital deafness?
Rubella - a less severe viral exanthem that starts on the face and spreads to the trunk and extremities. Many infections are subclinical, but rubella can cause severe birth defects, including congenital deafness, when infection occurs during the prenatal period`
Mumps causes…
Caused by an RNA paramyxovirus that replicates in the upper respiratory tract and causes parotiditis and frequently orchitis. Pancreatitis and meningitis may also be present
Measles presentation? Rare complication?
Presents with a relatively nonspecific prodrome of cough, fever and runny nose. The rash develops 1-2 days after the appearance of Koplik’s spots (red oral lesions with blue-white centers). Spreads from head to toe over a 3-day period. Rarely, it can cause subacute sclerosing panencephalitis in which patients exhibit pyschoneurologic deterioration 10 or more years after infection with the measles virus. It is a progressive disorder that can manifest with seizures, myoclonus, ataxia, and personality changes and eventually results in death
What is an extraintestinal manifestation of IBS that commonly presents on the lower legs? Treatment?
Skin lesions such as pyoderma gangrenosum (half of all cases are extra intestinal IBS manifestations). Extremely painful and on the legs. Is not correlated with flares of IBS.
Treatment is steroids (because the sore is not infected but rather due to his own immune system)
Anorexia nervosa is associated with what?
Osteoporosis (decreased estrogen over time)/stress fractures, amenorrhea, lanugo (fine body hair), severe weight loss, anemia and electrolyte imbalances
What is the most common inflammatory marker in polymyositis?
Lymphocytes
In polymyositis, an infiltrate of CD8+ T-lymphoctytes and macrophages surround and destroy healthy muscle fibers
What is HBV infection treated with? Hep c?
Hep B - Lamivudine and interferon-a
Hep C - Ribavirin and pegylated interferon-a2
People who are homozygous for mutations of what receptor are immune to certain strains of HIV?
Mutations of the CCR5 chemokine receptor on macrophages that facilities viral entry into cells
Almost never seen in those of asian or african descent
List the four mechanoreceptors and what stimuli they are responsible for
Meissner corpuscles: light discriminatory touch
Pacinian corpuscles: Perception of pressure, coarse touch, vibration and tension. *Often damaged in diabetic neuropathy
Ruffinini end organ and Merkel’s disks: sustained pressure, deep static touch (shapes, edges)
SIADH causes? Results?
Causes: ectopic ADH (small cell lung cancer), CNS disorders/head trauma, pulmonary disease, drugs (cyclophosphamide)
Results in excessive water retention, hyponatremia with continued urinary Na+, urine osmolarity>serum osmolarity
Which way does the oxygen-hemogobin dissociation curve shift if there is reduced affinity of hemoglobin for oxygen? What does this mean? What can cause it?
LEFT
Reduction in affinity enables increased delivery of oxygen to peripheral tissues
Increased temperature, acidity, increased metabolic demands (exercise) and 2,3-DPG can all shift the curve left
Hepatic adenoma may be caused by what?
Oral contraceptive use
Rare, benign liver tumor often related to oral contraceptive or anabolic steroid use; may regress spontaneously or rupture (abdominal pain and shock)
