By M. Murak. Dominican University of California.
Transmission of West Nile virus by blood products has led to new donor questions to eliminate donors at risk for this disease buy amantadine 100 mg fast delivery. A nucleic acid–based test for all donated units was introduced in June 2003 purchase amantadine 100 mg mastercard. A 49-year-old woman is admitted to the hospital with newly diagnosed severe anemia buy 100 mg amantadine overnight delivery. Her hemoglobin level is 7 g/dl order 100mg amantadine amex, and she has shortness of breath and fatigue. She denies any obvious source of blood loss, such as menorrhagia or rectal bleeding. Before you leave the room to write your orders, you explain the risks and benefits of blood product transfusion. Which of the following statements about blood components is true? Whole blood transfusion would be preferable to red cell transfusion in this patient B. Leukocyte reduction reduces febrile transfusion reactions C. Cryoprecipitate consists of albumin and platelets D. Single-donor platelet transfusions carry a higher risk of blood-borne infection than platelet concentrates Key Concept/Objective: To understand the components of whole blood Except for some autologous blood programs that use whole blood rather than packed red cells, use of whole blood has now been almost completely supplanted by therapy employ- ing specific blood components. To prevent transfusion reactions or to delay alloimmu- nization, red cells are further processed by leukocyte reduction or washing to remove plasma proteins. Current filter technology reduces white cell counts to less than 5 × 106 cells per unit, a concentration that is sufficient to reduce febrile transfusion reactions and 5 HEMATOLOGY 23 delay alloimmunization and platelet refractoriness. With single-donor platelet therapy, there is a reduction in the risk of blood-borne infection and antigen exposure, because the product is from one donor rather than four to six; disadvantages are a longer collection time, greater cost, and often limited supply. Fresh frozen plasma (FFP) that is frozen with- in 8 hours of collection contains all the procoagulants at normal plasma concentrations. Cryoprecipitate consists of the cryoproteins recovered from FFP when it is rapidly frozen and then allowed to thaw at 2° to 6° C. These cryoproteins include fibrinogen, factor VIII, von Willebrand factor, factor XIII, and fibronectin. A 58-year-old man with acute myelogenous leukemia received chemotherapy 10 days ago. He now pres- ents to the emergency department with severe fatigue and shortness of breath. Results of complete blood count are as follows: white cell count, 800/µl; hemoglobin level, 7. Which of the following statements regarding indications for transfusion of blood products is true? In patients with acute blood loss, the first treatment goal is transfusion of packed red blood cells B. Platelet transfusions are contraindicated in autoimmune thrombocy- topenia C. The prevalence of bleeding increases significantly below a threshold of about 10,000 platelets/µl in otherwise asymptomatic patients D. In chronically anemic patients, red cell 2,3-diphosphoglycerate pro- duction is decreased to maximize the red blood cells’ oxygen affinity Key Concept/Objective: To know the indications for transfusion of blood products The decision whether to use red cells depends on the etiology and duration of the anemia, the rate of change of the anemia, and assessment of the patient’s ability to compensate for the diminished capacity to carry oxygen that results from the decrease in red cell mass. Restoration of intravascular volume, usually with crystalloid, ensures adequate perfusion of peripheral tissue and is the first treatment goal for a patient with acute blood loss. In general, the decision to transfuse platelets rests on the answers to two questions: (1) Is the thrombocytopenia the result of underproduction or increased consumption of platelets? Thrombocytopenia can result from decreased production caused by marrow hypoplasia or from increased consumption caused by conditions such as idiopathic thrombocytopenic purpura (ITP). Studies have shown that the prevalence of bleeding increases significantly below a threshold of about 10,000 platelets/µl in otherwise asymptomatic patients.
Removal of his baseball cap reveals a 6 × 15 cm patch of a sharply demarcated buy discount amantadine 100 mg, erythematous order amantadine 100mg amex, scaly rash on his anterior scalp and forehead discount amantadine 100mg mastercard. Skin and nail exam- ination reveals no further rashes in the groin discount amantadine 100mg free shipping, gluteal fold, or umbilicus and no nail pitting. His right ankle is normal in color but swollen and boggy, with decreased range of motion and mild tenderness to palpation. What other testing should be performed on this patient? Urethral, anal, and pharyngeal swabs for gonorrhea D. Antinuclear antibody test Key Concept/Objective: To understand that new psoriasis can be associated with HIV infection, especially in patients who have risk factors for sexually transmitted disease or who have exami- nation findings that suggest HIV infection This patient is presenting with new-onset psoriasis and likely psoriatic arthritis. He also has a risk factor for HIV infection (unprotected sex with men), as well as unexplained lym- phadenopathy. More careful examination may reveal other clues to HIV infection, includ- ing oral candidiasis, oral hairy leukoplakia, gingivitis, or seborrheic dermatitis. Though gout can affect the ankle joint, there is usually much greater pain and inflammation associated with acute gouty arthritis. Furthermore, uric acid levels are not always helpful in making a diagnosis of gout, because they can be nor- mal in up to 25% of patients with gout. Swabs for gonorrhea can be helpful in diagnosing septic arthritis, though as with gout, the involved joint is usually more obviously inflamed (warm, red, very tender to any movement). HLA-B27 testing has no role in the diagnosis or treatment of psoriatic arthritis. The HLA-B27 test is often positive in patients with Reiter syndrome, although this patient does not have the classic tetrad of symptoms (see Question 12). Antinuclear antibody test is not warranted, because this patient does not have any symptoms or findings that suggest SLE. A 35-year-old woman presents to clinic complaining of a pruritic rash on her hands. She denies recent- ly changing the detergents and soaps she uses, and she does not wear jewelry. She admits to being under a great deal of stress at work over the past few days. Examination is notable for small, clear vesicles on the sides of her fingers, and there is associated evidence of excoriation. Seborrheic dermatitis Key Concept/Objective: To know the differential diagnosis of eczematous disorders and to recog- nize the presentation of dyshidrotic eczema Eczema is a skin disease characterized by erythematous, vesicular, weeping, and crusting patches associated with pruritus. The term is also commonly used to describe atopic der- matitis. Examples of eczematous disorders include contact dermatitis, seborrheic dermati- tis, nummular eczema, and dyshidrotic eczema (pompholyx). Contact dermatitis is very common and can be induced by allergic or irritant triggers. The distribution of the rash in contact dermatitis coincides with the specific areas of skin that were exposed to the irri- tant (e. This patient does not have a history of any partic- ular exposure, and the rash occurs only on the sides of several fingers. Seborrheic der- matitis is also common and is characterized by involvement of the scalp, eyebrows, mus- tache area, nasolabial folds, and upper chest. Nummular eczema is characterized by coin- shaped patches occurring in well-demarcated areas of involvement. This patient most like- ly suffers from dyshidrotic eczema, which tends to occur on the side of the fingers, is intensely pruritic, and often flares during times of stress. The treatment includes com- presses, soaks, antipruritics, and topical steroids. A 21-year-old man presents to the acute care clinic complaining of itching.
Most cases of hematogenous osteo- myelitis are monomicrobial buy discount amantadine 100 mg. In newborns effective amantadine 100 mg, group B streptococci and gram-negative bacilli are common amantadine 100 mg online. In children buy amantadine 100 mg low cost, streptococci and Haemophilus influenzae are often seen. However, evidence from a retrospective study in Canada showed that vaccination of infants and children succeeded in eliminating H. Polymicrobial hematogenous osteomyelitis is usually caused by S. A 27-year-old man presents to the emergency department for evaluation of fever and rash. He was well until 4 days ago, when he developed fever, a rash on his left wrist and both ankles, and diffuse body aches. He states that he just returned from a trip to the mountains of northern Georgia, where he spent a week mountain biking. This is an annual trip that he and friends take in April. He denies having cough, shortness of breath, sore throat, or dysuria, but he has developed some moderate, constant abdominal pain. He states that his rash has now spread to involve most of his trunk. He denies having any sexual contact other than with his wife of 4 years. He takes no prescription or over-the-counter medications. Which of the following statements regarding Rocky Mountain spotted fever (RMSF) is false? Over 90% of all cases of RMSF occur from early spring to early autumn and are most often reported from the southeastern and south central United States B. The diagnosis of RMSF is made on the basis of the presence of the classic rash C. The diagnosis of RMSF is based on clinical features and an appropri- ate epidemiologic setting rather than on any single laboratory test D. Doxycycline is the preferred agent for the treatment of RMSF in all patients except pregnant women Key Concept/Objective: To understand the diagnosis and management of RMSF Over 90% of all cases of RMSF occur from early spring to early autumn. It is most often reported from the southeastern and south central United States. The rash typically develops on the third to the fifth day of illness. The appearance of the rash may be delayed, however, and in a small percentage of patients, the rash does not develop at all. Delay or absence of the rash greatly complicates clinical diagnosis. In one study, only 14% of RMSF patients had a rash on the first day of illness, and fewer than 50% developed a rash in the first 72 hours of illness. The absence of rash does not correspond to milder disease; a small percentage of patients with so-called spotless RMSF have fatal illness. The diagnosis of RMSF is notoriously difficult, even for experienced physicians in highly endemic areas. It is axiomatic that the diagnosis of RMSF must be based on the clinical features and an appropriate epidemiologic setting rather than on any sin- gle laboratory test. There is no completely reliable diagnostic test for RMSF in the early phases of illness; thus, therapy should always begin before laboratory confirmation is obtained. Doxycycline is the preferred agent in all patients except pregnant women, for whom chloramphenicol remains the agent of choice.
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