Sangre Flashcards
Que factor es estimulada su liberación en células endoteliales como tratamiento para sangrado?
Von Willebrand
La circulación hiperfinámica (sonidos altos S1 y S2 y murmuro sistólico) ocurren por anemia severa. En estos pacientes la SaO2 es normal pero la ___ es disminuida
SvO2 - la saturación de oxígeno en la arteria pulmonar por menos concentración de hemoglobina
Patient presents with splenomegaly, anemia, reticulocytosis, ↑ LDH, ↑ unconjugated bilirubin, and ↓ haptoglobin; these findings suggest a diagnosis of hemolytic anemia. He was previously treated with nitrofurantoin. What is his diagnosis?
Glucose-6-phosphate dehydrogenase deficiency (G6PD) results in impaired production of NADPH.
Patients typically develop acute hemolysis 2–3 days after starting medications like anti-malaria drigs or sulfa drugs
This patient’s urinalysis (significant proteinuria, glycosuria, fatty casts) in the setting of lower extremity swelling and weight gain are highly suggestive of nephrotic syndrome. His flank pain and hematuria with an identified filling defect indicate an acute renal vein thrombosis, likely a result of a hypercoagulable state induced by nephrotic syndrome. Which is the cause?
Nephrotic syndrome is characterized by a massive renal loss of protein due to structural damage of the glomerular filtration barrier which leads to the loss of antithrombin III, leading to a hypercoagulable state due to decreased inhibition of Factor IIa and Factor Xa.
A chromosomal t(15;17) translocation is characteristic of acute promyelocytic leukemia (M3), which would explain this patient’s B symptoms (low-grade fever, fatigue) and signs of coagulopathy (easy bruising, fibrinogen).
What treatment do you give her?
Retinoic acid binds its nuclear receptors to stimulate histone acetylation, which promotes gene expression that regulates the maturation and proliferation of granulocytes.
Retinoic acid binds its nuclear receptors to stimulate histone acetylation, which promotes gene expression that regulates the maturation and proliferation of granulocytes. Lab show low leukocyte count. Which of the following actions by the physician is most appropriate?
Discontinue methimazole
This patient recently began taking methimazole, an antithyroid drug, which is associated with a risk of agranulocytosis that usually occurs within the first 3 months of treatment.
A 75-year-old man comes to the physician because of fatigue and decreased urine output for 1 week. He takes ibuprofen as needed for lower back pain and docusate for constipation. Physical examination shows tenderness to palpation over the lumbar spine. There is pedal edema. Laboratory studies show a hemoglobin concentration of 8.7 g/dL, a serum creatinine concentration of 2.3 mg/dL, and a serum calcium concentration of 12.6 mg/dL. Urine dipstick is negative for blood and protein. Which of the following is the most likely underlying cause of this patient’s symptoms?
Precipitation of excessive nephrotoxic immunoglobulin light chains (Bence Jones proteins) is the underlying cause of myeloma cast nephropathy and the most common form of acute or subacute kidney injury in patients with multiple myeloma (MM).
This patient developed fever, hypotension, tachypnea, tachycardia, flank pain, and likely hemoglobinuria (dark brown urine) within 1–2 hours of receiving a blood transfusion, which is consistent with an acute hemolytic transfusion reaction (AHTR). AHTR is a type II hypersensitivity reaction, in which preformed antibodies cause activation of the complement system (C5-C9), which results in intravascular hemolysis. Further evaluation of this patient is most likely to show which of the following?
A positive direct Coombs test indicates that RBCs in the patient’s blood have bound antibodies. This laboratory result would be consistent with a diagnosis of acute hemolytic transfusion reaction (AHTR), in which donor RBC lysis is mediated by preformed antibodies in the patient’s serum. AHTRs are most commonly due to ABO incompatibility, and less commonly due to a mismatch and incompatibility of minor RBC antigens (e.g., anti-Jka, anti-Rh). Patients with a history of previous transfusions, especially those with SCD, are more likely to be subject to alloimmunization against foreign blood product antigens and subsequently have transfusion-related complications, including but not limited to AHTRs.
A 34-year-old woman comes to the physician because of recent fatigue and weakness that is exacerbated by cross-country skiing. Four weeks ago, she was diagnosed with pneumonia; sputum cultures on Eaton agar showed organisms that lacked a cell wall. Physical examination shows conjunctival pallor and cyanosis of the fingertips. Both lungs are clear to auscultation. Which of the following findings is most likely to confirm the diagnosis?
Erythrocytes coated with autoantibodies
This patient presents with the hallmark sign of cold agglutinin disease (acrocyanosis in response to exposure to cold temperatures). Cold agglutinins are cold-reactive IgM autoantibodies that are located on the surface of erythrocytes and may lead to an increased turnover of RBCs, resulting in hemolytic anemia. AIHA can be diagnosed with the direct Coombs test, which uses anti-human globulin (Coombs reagent) to bind autoantibodies attached to the patient’s erythrocytes.
Three weeks after starting a new medication for hyperlipidemia, a 54-year-old man comes to the physician because of pain and swelling in his left great toe. Examination shows swelling and erythema over the metatarsophalangeal joint of the toe. Analysis of fluid from the affected joint shows needle-shaped, negatively-birefringent crystals. Which of the following best describes the mechanism of action of the drug he is taking?
Niacin is a lipid-lowering medication that decreases LDL and increases HDL levels via inhibition of hepatic VLDL synthesis. Common side effects of niacin include exacerbation of gout (due to niacin-induced hyperuricemia), flushing, hyperglycemia, GI upset, and increased LFTs.
This patient’s flu-like symptoms, necrotic lymphadenopathy (buboes), and history of recent camping in California should raise suspicion for bubonic plague. The lymph node Gram stain (gram-negative coccobacilli with bipolar staining and a safety-pin appearance) is consistent with Yersinia pestis infection.
Yersinia pestis, the pathogen responsible for the bubonic plague, is transmitted to humans by flea bites and has a natural long-term reservoir in rodents (e.g., squirrels, rats, prairie dogs, rabbits). It is still found in rural areas of the western US (California, Arizona, New Mexico), especially in forests and grasslands. The diagnosis is confirmed via cultures and Wayson staining showing bipolar staining (closed safety-pin appearance), but treatment should begin as soon as bubonic plague is suspected. Aminoglycosides are the treatment of choice for plague.
This woman with a history of acute lymphoblastic leukemia (ALL) has secondary amenorrhea due to premature ovarian failure, most likely related to chemotherapy she received in the past. Physical examination shows a female phenotype, whereas chromosomal analysis shows a male genotype.
Allogeneic stem cell transplantation is used in post-remission therapy of patients with ALL who have a high risk of relapse. In contrast to autologous stem cell transplantation, which involves the removal, storage, and retransfusion of a patient’s own cells, allogenous stem cell transplantation refers to the administration of hematopoietic stem cells from a sibling or unrelated donor. Chromosomal analysis in this female patient shows a male genotype (46,XY karyotype) because she received stem cells from a male donor (e.g., sex-mismatched transplantation). This patient’s premature ovarian failure is most likely related to cytotoxic effects of chemotherapy and radiation administered prior to the allogeneic stem cell transplantation.
Multiple miscarriages, deep vein thrombosis (asymmetric calf swelling with a palpable cord), and prolonged activated partial thromboplastin time (aPTT) are consistent with antiphospholipid syndrome (APS). Which of the following is most likely to confirm the diagnosis?
The presence of procoagulant antiphospholipid antibodies such as anti-β2-glycoprotein 1 antibodies confirms the diagnosis of APS. The antibodies in APS are thought to form complexes with anticoagulant proteins, thereby inactivating them (e.g., protein C, protein S, antithrombin III), and activate platelets and vascular endothelium. These effects induce a hypercoagulable state with an increased risk of arterial and venous thrombosis as well as pregnancy loss. Another important antiphospholipid antibody implicated in APS is the lupus anticoagulant, which is responsible for the prolonged aPTT seen in this patient.
A 68-year-old man comes to his physician because of fatigue, night sweats, chills, and a 5-kg (11-lb) weight loss during the past 3 weeks. Eight years ago, he was treated for a hematological malignancy after biopsy of a neck swelling showed CD15+ and CD30+ cells. Since his treatment, the patient had been feeling well until he developed symptoms three weeks ago. Physical examination shows conjunctival pallor and scattered petechiae. A peripheral blood smear is shown ( a cell that contains an Auer rod). Which of the following is the most likely explanation for this patient’s current condition?
Auer rods in myeloblasts are a characteristic morphological feature of certain subtypes of acute myeloid leukemia (AML), which typically manifests with pallor (due to anemia), petechiae (due to thrombocytopenia), and constitutional symptoms such as fatigue, night sweats, chills, and weight loss. Radiotherapy and alkylating chemotherapeutic agents (e.g., procarbazine, ifosfamide), both of which are commonly used to treat Hodgkin lymphoma, are important risk factors for myelodysplastic syndrome (MDS) and AML.
This patient’s symptoms and biopsy results are consistent with follicular lymphoma (Histopathologic examination of a cervical lymph node biopsy specimen shows a nodular proliferation of centrocytes and centroblasts that stain positive for CD20. Genetic analysis shows a reciprocal translocation of chromosomes 14 and 18.), which is associated with mutation of the Bcl-2 oncogene.
Overexpression of Bcl-2 due to a gain of function mutation of the Bcl-2 oncogene inhibits the programmed cell death of B lymphocytes, causing follicular lymphoma. Bcl-2 proteins are antiapoptotic gene products that prevent mitochondrial leakage of cytochrome c (release of cytochrome c initiates apoptosis via activation of caspases). Disruptions in apoptosis of damaged or faulty cells cause immortality of neoplastic tissue and thus promote cancer development.
