Block 34 Flashcards
Erythromycin effect on P450
Its a C-P450 inhibitor
Trastuzumab
Is a monoclonal antibody used in the managment of breast cancer with HER2 positive.
- it binds to a portion of extracellular domain of HER2 and prevents activation of a transmembrane tyrosine kinase.
- this downregulates cellular proliferation and promotes apoptosis.
- approximately 20% of all invasive breast cancers overexpress HER2, this can also be found in other solid tumors.
Colchecine side effects
Due to the fact that it inhibits microtubule formation it leads to diarrhea many times, less commonly nausea, vomiting and abdominal pain.
Secondary lactose intolerance
- it due to secondary lactase deficiency, an aquired condition resulting from inflammation/infection, overgrowth and infectious enteritis that causes injury to the mucosal brush border of the small bowell where lactase is expressed.
- the fermentation of undigested lactose by gut bacteria leads to increased production of short chain fatty acids that acidify the stool(decrease PH).
- during this process hydrogen gas is also produced leading to increased breath hydrogen content.
- in addition the high amounts of undigested lactose in the bowel lead to elevated stool osmolarity which attracts excess water in the bowel lumen causing osmotic diarrhea.
What is the most common type of kidney stones
Calcium stones represent 75-80% of all renal caliculi.
-the most common cause of kidney stones are hypercalciuria with normal calcemia in blood.
Cancer cell cycle
M- cell division - vinca alkaloids and taxanes (vincristine)
G1- organele duplication
S- synthesis - antimetabolites
G2- DNA damage and repair - bleomycin and doxurubicin
Infective endocarditis renal involvment
- elevated creatine and hematuria and proteinuria suggest renal insufficiency due to nephritic syndrome.
- in some patients of infective endocarditis may be complicated by depositibo of circulating immune complexes in the glomelular capillary wall resulting in glomerulonephritis.
- this can be seen as capillary wall thickening with sub endothelial and sub epithelial deposit formation.
- hypercellularity similar that seen in PSGN or MPGN
Aplastic anemia
- fatigue,weakness, conjuctival pallor and decreased hemoglobin suggestive of anemia
- bruising not associated with trauma, suggest thrombocytopenia
- high lipid content of the bone marrow aspirate suggestive of hematopoietic cell aplasia or hypoplasia.
- as with most anemia, increased production of erythropoietin by the kidney would be expected.
Tumor lysis syndrome(TLS)
Oncologic emergency. It often develops during chemotherapy for high grade lymphomas, leukemia and other tumors that have rapid cell turnover and high sensitivity to chemotherapy.
- when a lrage number of tumor cells are destroyed during chemotherapy, intracellular ions such as K+, uric acid, and phosphorus are released into serum and to kidney,
- uric acid at physiologic PH is soluble, but precipitates in acidic environment, the lowest PH in the nephron is found in the distal tubule and collecting ducts so these are the segments of nephron that may become obstructed by uric acid crystals.
- the risk of TLS can be reduced by urine alkalization and hydration.
- allupurinol is used to reduce uric acid production during breakdown of tumor cells.
Sickle cell disease, spleen changes
- sickle cell disease leads to splenic infarctions, however repeated infarctions eventually leads to significant scarring, fibrosis and atrophy of the spleen which is likely to present in adults.
- in the long term sickle cell anemia can cause macrocytic anemia due to the fact that it needs high folate in erythrocytes turnover.
Enterococcal endocarditis
Usually occur in elderly men who have recently undergone manipulation of areas colonized by this organism.
- the genitourinary tract is the most common portal of entry, GI or obstetric procedures are also risk factors.
- enterococci can also cause UTI, wound infection …
- enterococci are gamma hemolytic, catalase negative, PYR positive, lancified group D gram positive cocci that can grow in hypertonic saline and bile.
Ivabradine mechanism of action
Its the only drug used in HF that can slow heartrate without any effect on contractility and relaxation.
- it slows the rate of sinoatrial node firing be selective inhibition of funny sodium channels, therapy prolonging the slow depolarization phase.
- ivabradine is used in certain patients with chronic HF with reduced ejection fraction and persistent symptoms despite appropriate medical therapy. It has been shown to reduce the risk of hospitalization due to HF.
Marfan syndrome signs and symptoms
- taller slender body
- arachnodactyly
- breastbone dips inward or protrudes outward(sternum is inward)
- joint hypermobility
- increased arm to height ratio
- ectopic lens
- kyphosis and or scolisois
Which substance is responsible for stimulation of the first step in gluconeogenesis
Pyruvate carboxylase —> oxaloacetate.
-its stimulated via increased Actyl-Coa
Citrate is important in regulation of what enzyme in gluconeogenesis
-citrate is an important positive regulator of actyl-coa carboxylase and 1,6 bisphosphatase.
Inhaled anasthesia leads to increase in
- increase in cerebral blood flow
- inhaled anesthetics have shown to affect K+ channels in the neuronal membrane and lock them in a state of hyperpolarization.
- in the brain these anasthetics lead to decrease vascular resistance and increase blood flow —> increased intracranial pressure.
- in kidneys they decrease GFR and RPF, and increase renal vascular resistance.
- they decrease hepatic blood flow
- all inhaled anesthetics except nitrous oxide are respiratory depressant, they decrease tidal volume and minute ventilation and causes hypercapnia, also they lead to decrease mucocilliary clearance -> postoperative atelectasis (halothone and sevoflurane -> bronchodilation, used in asthmatic patients)
- cardiovascular depression -> decreased CO and increase atrial and ventricular pressure
Uretral circulation
- the proximal ureter is supplied via branches of the renal artery
- the distal ureter, arterial blood supply arises from superior vesical artery.
- in between (the middle ureter) the arterial supply is anasmotic and highly variable with possible afferent branches from gonadal, common and internal iliac, aorta and uterine arteries
Aortocavitary fistula
- uncommon complication of infective endocarditis caused by extension of the infection from the valve to the adjacent myocardium.
- during normal cardiac cycle, central aortic pressure (120/80) is higher than right ventricular pressure (25/5) during systole and diastole, thus a fistula between the two will most likely lead to continuous flow from aorta to the right ventricle
