Normal Size Small Size show me how
Surgery Review 1
SR 1: Cell bio, hematology, transfusion, immunology,infection, abx, pharmacology
|What increases membrane fluidity?
|Adhesion molecules which anchor cells to each other and to the extracellular matrix
|Desmosomes and hemidesmosomes
|Cell-to-cell occluding junctions that form an impermeable barrier (i.e. epithelium)
|Phases of the cell cycle
|G1 (most variable – determines cell cycle length), S (DNA replication), G2, M
|What phase of the cell cycle is most sensitive to radiation therapy?
|M - mitosis
|Which phase of the cell cycle do growth factors affect?
|What are the phases of mitosis?
|Prophase (spindle formation) Metaphase (chromosome alignment) Anaphase (chromosomes pulled apart) Telophase (separate nucleus re-forms around each set of chromosomes)
|The outer membrane of the nucleus of a cell is continuous with what?
|rough endoplasmic reticulum
|Where do steroid hormones bind their receptors?
|Where do thyroid hormones bind their receptors?
|What are the purines?
|guanine and adenine
|What are the pyrimidines?
|cytosine, thymidine (ony in DNA), uracil (only in RNA)
|What is the process by which mRNA is used as a template by ribosomes for synthesis of protein?
|What cell subunits read mRNA, then bind appropriate tRNAs that have amino acids, and eventually make proteins?
|What are the products of glycolysis?
|1 glucose molecule generates 2 ATP and 2 pyruvate molecules
|What are the products of the Krebs cycle?
|2 pyruvate molcules form NADH and FADH2 which enter the electron transport chain to create ATP
|Overall, how many ATP are formed from one glucose molecule?
|What are fats and lipids not available for gluconeogenesis?
|acetyl CoA (breakdown product of fat metabolism) cannot be converted back to pyruvate
|What is the function of the rough endoplasmic reticulum? What organ has an increase in this?
|synthesizes proteins that are exported (increased in pancreatic acinar cells)
|What is the function of the smooth endoplasmic reticulum? What organ has an increase in this?
|lipid/steroid synthesis and detoxifies drugs (increased in liver and adrenal cortex)
|What are the three initial responses to vascular injury?
|vasoconstriction, platelet adhesion, and thrombin generation
|What combines with platelets to form the platelet plug?
|What are the functions of thrombin?
|Converts fibrinogen to fibrin and fibrin split products, activates factor V, VII, and activates platelets
|What are the functions of antithrombin III?
|Binds and inhibits thrombin, inhibits factors IX, X, and XI
|What are the functions of protein C and protein S?
|Protein C degrades factors V, VIII, and fibrinogen; proteins S acts as a cofactor for protein C
|What is the function of TPA?
|tissue plasminogen activator – released from endothelium and converts plasminogen to plasmin
|What is the function of plasmin?
|Degrades factors V, VIII, fibrinogen, and fibrin causing a loss of the platelet plug
|Which clotting factor has the shortest half life?
|What is the only factor not synthesized in the liver?
|factor VIII – synthesized in endothelium
|What are the vitamin K dependent factors?
|II, VII, IX, X, protein C + S
|How long after administration does vitamin K take effect? What about FFP?
|Six hours for vit K, FFP is immediate and lasts 6 hours
|What is the normal half-life of RBCs? Platelets? PMNs?
|RBCs – 120 days platelets – 7 days PMNs – 1-2 days
|What factors does PT measure?
|II, V, VII, and X and fibrinogen
|What factors does PTT measure?
|All factors except VII and XIII
|What is the most common cause of surgical bleeding?
|What are the types of Von Willebrand’s disease?
|Types I+III have a reduced quantity of vWF type II has a defect in vWF itself (qualitatively poor) type I is most common but type III is most severe
|What is the function of vWF?
|Links GpIb receptors on platelets to collagen and binds factor VIII
|What tests for Von Willebrand’s disease?
|What is the only inherited coagulopathy with long bleeding time?
|Von Willebrand's Disease (autosomal dominant)
|What is the treatment for a hemophiliac joint?
|ice, range of motion, factor VIII concentrate or cryoprecipitate if necessary – NO aspiration
|What is the treatment for Von Willebrand’s Disease?
|Types I+III – cryo, DDAVP, or conjugated estrogens type II cryo only
|Why does a child with hemophilia not bleed during his circumcision?
|Factor VIII crosses the placenta
|What is the pathophysiology of Glanzmann’s thrombocytopenia?
|GpIIb/IIIa receptor deficiency of platelets. Decreased platelet aggregation. Fibrin normally links Gp IIb/IIIa receptors
|What is the pathophysiology of Bernard Soulier syndrome?
|GpIb receptor deficiency of platelets. Decreased adherence of exposed collagen. vWF normally links Gp Ib to collagen
|What is the mechanism of clopidogrel (Plavix)?
|ADP receptor antagonist
|What antibiotics can bind platelets, thus increasing bleeding times?
|PCNs and cephalosporins
|What is the mechanism of cilostazol (Pletal)?
|type 3 phosphodiesterase inhibitor increasing cAMP and inhibiting platelet aggregation
|What is the mechanism of pentoxifylline (Trental)?
|nonselective phosphodiesterase inhibitor increasing cAMP and inhibiting platelet aggregation; also improves red blood cell deformability
|What is the treatment of HIT (heparin induced thrombocytopenia)?
|stop heparin, argatroban, hirudin, or dextran to anticoagulate
|What are platelet goals in a thrombocytopenic patient in the perioperative period?
|Keep plateltes >50,000 before surgery and >20,000 after surgery
|What are the most common inherited thombophilias?
|Factor V Leiden, Prothrombin mutation (GP20210), Hyper-homocysteinemia
|What is the pathophysiology of factor V Leiden?
|Defect on factor V which causes resistance to activated protein C
|What is the treatment of hyperhomocysteinemia?
|folic acid and B-12
|How is antiphospholipid syndrome diagnosed?
|Test for lupus anticoagulant, prolonged PTT (not corrected with FFP), positive Russel viper venom time, false positive RPR for syphilis
|How does cardiopulmonary bypass cause a hypercoagulable state?
|Activates factor XII (Hageman factor)
|What are the indications for an IVC filter?
|Patients with contraindication for anticoagulation, PE while on anticoagulation, free floating femoral/iliofemoral/IVC DVT, previous pulmonary embolectomy
|What is the mechanism of warfarin?
|Prevents vitamin K dependent decarboxylation of glutamic residues on clotting factors
|How do sequential compression devices work?
|Improve venous return and also induce fibrinolysis by releasing tPA
|What drug reverses heparin?
|What is the most common complication of heparin reversal with protamine?
|What are the complications of long term heparin?
|Osteoporosis and alopecia
|What are the symptoms of a protamine reaction? What patients are most susceptible?
|Hypotension, bradycardia, decreased heart function. Protamine cross reacts with NPH insulin or previous exposure, but 4-5% of all patients will have a reaction
|What is the mechanism of Argatroban?
|Direct thrombin inhibitor
|What are two common anti-fibrinolytics and their mechanism of action?
|Aminocaproic acid (Amicar) – inhibits fibrinolysis by inhibiting plasmin Aprotinin (Trasylol) – inhibits fibrinolysis by inhibiting plasminogen activation
|What are indications for giving antifibrinolytics?
|DIC, overdose of tPA, or excessive bleeding after cardiopulmonary bypass
|What laboratory value is followed when given thrombolytics?
|fibrinogen levels - <100 associated with increased risk and severity of bleeding
|What are absolute contraindications to thrombolytic use?
|Active internal bleeding recent CVA (<2 months) intracranial pathology
|What blood products do not carry any risk of HIV or hepatitis?
|albumin and serum globulins
|What are indications for using CMV-negative blood?
|Low birth weight infants, transplant patients (bone marrow or solid organ)
|What is the number 1 cause of death from transfusion reaction?
|Clerical error leading to ABO incompatibility
|What are the communicable disease risks of a blood transfusion?
|CMV is highest Hep C 1:30-150,000 HIV 1:500,000
|What is an effect of stored blood?
|Decreased 2,3-DPG – left shift in oxygen disassociation curve causing an affinity for oxygen
|What are the symptoms of an acute hemolysis reaction? What is the treatment?
|Back pain, fever, chills, tachycardia, hemoglobinuria, can lead to ATN, DIC, and/or shock. Treat with fluids, diuretics, HCO3-, pressors, and histamine blockers (Benadryl)
|What is the most common transfusion reaction? What is its cause?
|Febrile nonhemolytic transfusion reaction caused by recipient antibody reaction against WBCs in donor blood
|What is the cause of anaphylaxis during a blood transfusion?
|IgG against IgA in IgA-deficient recipient
|What is the cause of urticaria during a blood transfusion?
|Usually a reaction against plasma proteins or IgA in the transfused blood
|What is the cause of transfusion related lung injury (TRALI)?
|Antibodies to recipients WBCs, clot in pulmonary capillaries
|What is the most common bacterial contaminent in blood?
|GNRs (usually E. coli)
|What causes B cell maturation into plasma cells?
|What causes maturation of cytotoxic T cells?
|What is the function of cytotoxic T cells?
|recognizes and attacks non-self-antigens attached to MHC class I receptors (e.g. viral gene products)
|What is used to test cell-mediated immunity?
|Intradermal skin test
|What infections are associated with defects in cell mediated immunity?
|intracellular pathogens (TB, viruses)
|What cells are MHC class I present on? What about MHC class II?
|MHC class I are present on all cells, MHC class II are present on B cells, monocytes, and antigen presenting cells
|What cells are part of the bodies immunosurveillance for cancer?
|Natural killer cells
|What type of hypersensitivity reaction is IgE mediated with release of histamine, serotonin, and bradykinin in response to major basic protein from eosinophils, which have IgE receptors for the antigen
|Type I (allergic reaction)
|What type of hypersensitivity reaction is characterized by IgG or IgM reacting with cell-bound antigens (ABO blood type incompatibility, ITP, Graves’, myasthenia gravis)?
|What type of hypersensitivity reaction is characterized by immune complex deposition (serum sickness, rheumatoid arthritis, SLE)?
|What type of hypersensitivity reaction is a delayed-type hypersensitivity – antigen stimulation of previously sensitized T cells (TB skin test, contact dermatitis)?
|When do you give tetanus immune globulin?
|Patient has not been immunized or status unknown. If it has just been <5 years since last booster, only need to give tetanus toxoid
|What can enhance immune function in critical illness?
|What is the most common aerobic and anaerobic bacteria in the colon?
|Aerobic – E.coli; Anaerobic – bacteroides fragilis
|What is the pathophysiology of gram negative sepsis?
|Ednotoxin (lipopolysaccharide A) is released from bacteria, which triggers release of TNF-alpha (from macrophages), activating completent and coagulation cascades
|What is the first sign of early gram negative sepsis?
|What are indications for antibiotic treatment of an abscess?
|Diabetes, cellulitis, fever, leukocytosis, or bioprosthetic hardware
|What are the wound infection rates of the 4 types of wounds?
|Clean (hernia) – 2% Clean-contaminated (colon resection with prep) – 3-5% Contaminated (gunshot wound to bowel) – 5-10% Gross contamination (abscess) – 30%
|What is the most common organism overall in surgical wound infections?
|What are risk factors for wound infections?
|Long operation, hematoma or seroma, age, malnutrition, immunosuppresion, chronic disease (COPD, renal failure, liver failure, DM)
|What two infections can present within hours post-operatively?
|Clostridium perfringens and beta-hemolytic strep (produce exotoxins)
|What is the leading cause of infectious death after surgery and what organisms are most commonly involved?
|Nosocomial pneumonia – S. aureus and pseudomonas
|What are the four intraabdominal abscess locations?
|sub-diaphragmatic sub-hepatic inter-loop pelvic
|What infection can present with myonecrosis and gas gangrene associated with farming injuries?
|What organism presents with pulmonary symptoms commonly and can cause tortuous abscesses in cervical, thoracic, and abdominal areas? Treatment?
|Actinomyces – drainage and penicillin G
|What fungal infection presents with pulmonary and CNS symptoms? What is the treatment?
|Nocardia – drainage and sulfonamides (Bactrim)
|What fungal infection predominates in the Ohio and Mississippi river valleys and commonly presents with pulmonary symptoms? Treatment?
|Histoplasmosis – amphotericin for severe infections
|What is the most common cause for laparotomy in HIV patients?
|Opportunistic infections (CMV colitis – pain, bleeding, or perforation - most common), neoplastic disease is second most common
|What are the most common reasons of GIB in HIV?
|Lower > upper; UGIB – Kaposi sarcoma, lymphoma; LGIB – CMV, bacterial, HSV
|What is the treatment for a brown recluse spider bite?
|Dapsone, but may need debridement later
|What is the dominant organism in human, cat, and dog bites?
|Human – Eikenella – can cause permanent joint injury; Cat/dog – Pasteurella multocida
|What is the treatment for peritoneal dialysis catheter infections?
|intraperitoneal vancomycin and gentamicin, amphotericin for fungal infections; intraperitoneal heparin may help; remove of catheter if infection lasts 4-5 days
|What is endotoxin? Where does it come from?
|Lipopolysaccharide A from gram negative bacteria
|What is the mechanism of penicillins, cephalosporins, and carbapenems?
|Inhibitors of cell wall synthesis
|What is the mechanism of aminoglycosides?
|Inhibitors of 30s ribosome and protein synthesis – irreversible binding and bactericidal
|What is the mechanism of tetracycline, and linezolid?
|Inhibitors of 30s ribosome and protein synthesis – bacteriostatic
|What is the mechanism of erythromycin, clindamycin, and chloramphenicol?
|Inhibitors of 50s ribosome and protein synthesis
|What is the mechanism of quinolones?
|DNA gyrase inhibition
|What is the mechanism of rifampin?
|RNA polymerase inhibition
|What is the mechanism of metronidazole (Flagyl)?
|Produces oxygen free radicals that breakup DNA
|What is the mechanism of sulfonamides?
|PABA analogue, inhibit purine synthesis
|What is the mechanism of penicillin resistance?
|plasmids for beta-lactamase
|What is the mechanism of vancomycin? What is the mechanism of it's resistance?
|Inhibits cell wall synthesis; Altered cell wall (unable to bind)
|What is the mechanism of amphotericin
|binds sterols to alter fungal cell wall
|What is the most common mechanism of antibiotic resistance?
|transfer of plasmids
|What is the mechanism of MRSA resistance?
|mutation in cell wall binding protein
|What is the mechanism of aminoglycoside (gentamicin, tobramycin) resistance?
|Resistance due to modifying enzymes leading to decreased active transport
|What organisms are carbapenems least effective against?
|MEPP – MRSA, enterococcus, proteus, and pseudomonas
|What is a side effect of carbapenems?
|What are side effects of vancomycin?
|Redman syndrome (histamine release), nephrotoxicity, ototoxicity
|What are side effects of aminoglycosides?
|Reversible nephrotoxicity, irreversible ototoxicity
|What are some side effects of Bactrim?
|teratogenic, Stevens-Johnson syndrome, hemolysis in G6PD-deficiency
|What are the side effects of metronidazole (Flagyl)?
|disulfiram-like reaction, peripheral neuropathy
|What antiviral is used for HSV infections?
|What antiviral is used to treat CMV infections?
|Which antibiotics can bind platelets and increase bleeding times?
|PCNs and cephalosporins
|What drug can displace unconjugated bilirubin in newborns?
|What is the difference between 1st order and 0 order kinetics?
|1st order kinetics – drug is eliminated proportional to dose; 0 order kinetics – constant amount of drug is eliminated regardless of dose
|What is the fraction of unchanged drug reaching the systemic circulation?
|What is the difference between polar (or ionized) and nonpolar drugs?
|Polar drugs are more water soluble and more likely to be eliminated in unaltered form, whereas nonpolar drugs are more likely to be metabolized before excretion
|What is the mechanism of allopurinol?
|Xanthine oxidase inhibitor, blocks uric acid formation from xanthine; used for overproducers
|What is the mechanism of Probenacid?
|Increases renal secretion of uric acid; used for undersecreters
|What is the mechanism of statins?
|HMG-CoA reductase inhibitors
|What are potential side effects of statins?
|Liver dysfunction, rhabdomyolysis
|What is a potential side effect of promethazine (Phenergan)?
|Tradive dyskinesia (inihibits dopamine receptors)
|What is the mechanism of ondansetron (Zofran)?
|serotonin receptor inhibitor – antiemetic
|What is the mechanism of digoxin?
|Inhibits Na/K ATPase to increase myocardial calcium
|What is the effect of digoxin?
|Slows AV conduction, inotrope but decreases O2 consumption
|What is the best single agent shown to decrease mortality in CHF?
|What are some potential side effects of procainamide?
|Lupus-like syndrome, pulmonary fibrosis, and torsades
|What is a common side effect of gadolinium?
|What are the symptoms of ASA poisoning?
|tinnitus, headaches, N/V, respiratory alkalosis and metabolic acidosis
|What is the treatment for an acetominophen overdose?
|What is the mechanism and effect of reglan (metoclopramide)?
|Dopamine receptor blocker - Increases LES tone and gastric motility