- Etiology
- Pathology
- Epidemiology
- Management & Treatment
- Prevention
- Complications
- Prognosis
- Research Frontier
- Clinical Case Studies
- Study Questions
Myelodysplastic syndromes (MDS) represent a group of myeloid (bone marrow) stem cell disorders that gradually affect the ability of a person's bone marrow to produce normal red blood cells, white blood cells, and platelets.
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A 30-year-old man with a history of a cerebellar tumor that was resected when he was 20 years of age presents to his physician because of blood in his urine. He is concerned because his father's brother died early in life from complications of a metastatic tumor. He is evaluated with an ultrasound and found to have a mass in the left kidney. The kidney is removed, and the mass is diagnosed as a renal cell carcinoma. This patient most likely has a mutation at which of the following sites?
The correct answer is C. You answered A.
The location of the retinoblastoma gene is 13q14, and in familial cases, it is associated with retinoblastoma and osteosarcoma. 5q21 is the location of the APC gene, and in familial cases, it is associated with colonic adenocarcinoma. 17p13 is the location of the p53 gene, and in familial cases, it is associated with various sarcomas and with breast carcinoma.
3p25 is the location of the von Hippel-Lindau gene and in familial cases, it is associated with renal cell carcinomas and cerebellar hemangioblastomas.
A 44-year-old woman has myelodysplastic syndrome and has undergone myeloablative allogeneic stem cell transplantation. She has been neutropenic for 10 days and has developed a fever to 39.5°C (103.1°F). She has had a Port-a-Cath inserted for her intravenous access for the past 6 months. Her catheter site does not appear inflamed, and she has never tested positive for methicillin-resistant Staphylococcus aureus. What is the best initial choice of antibiotics for this patient?
The correct answer is D. You answered E.
The answer is D.(Chap. 104) General guidelines for the treatment of febrile neutropenia depend on the expected duration of neutropenia, previous infections, and recent antibiotic exposures. Each febrile neutropenic patient should be approached as a unique problem. However, several general guidelines can help in treating these patients. The initial regimen should include antibiotics with activity against both gram-negative and gram-positive bacteria. If the expected duration of neutropenia is expected to be greater than 7 days, as in this scenario, then the initial antibiotic choice could be (1) ceftazidime or cefepime, (2) piperacillin/tazobactam, or (3) imipenem/cilastatin or meropenem; all of these regimens have shown equal efficacy in large clinical trials. These antibiotics exhibit broad-spectrum efficacy against gram-positive and gram-negative organisms, including Pseudomonas aeruginosa. Double coverage of P aeruginosa is not necessary, and use of aminoglycosides alone is contraindicated because these do not provide coverage of gram-positive organisms. Other antibiotics not providing adequate gram-positive coverage include aztreonam and fluoroquinolones. In addition, routine addition of vancomycin is also not indicated because studies have not shown improved outcomes with increased toxic effects. Vancomycin should only be added when there is high suspicion of coagulase-negative staphylococcal infection or specific concerns regarding methicillin-resistant Staphylococcus aureus infection. However, the treating physician needs to be knowledgeable about his or her local epidemiology and resistance patterns and prescribe in accordance with this knowledge. Antifungal therapy is often added when there is persistent fevers at 4–7 days without a known source of infection. The choice of specific antifungal agent (echinocandin, azole, lipid formulation of amphotericin B) would depend on whether the patient was receiving antifungal prophylaxis and whether there were reasons to suspect a specific source of infection, such as a pulmonary source.