The current status of non-A, non-B viral hepatitis

Infectious and immunologic consequences of blood transfusion

Blood transfusions remain common practice in the critical care and surgical settings. Transfusions carry significant risks, including risks for transmission of infectious agents and immune suppression. Transmission of bacterial infections, although rare, is the most common adverse event with transfusion. The risk for transmission of viral infections has decreased over time, clearly because tests are becoming more sensitive in detecting certain viral infections such as hepatitis B, hepatitis C, and HIV. Several immunomodulatory effects are thought to be related to transfusions, and these can result in cancer recurrence, mortality, and postoperative infections. Numerous studies have been performed to examine the role of leukoreduction in decreasing these transfusion-related complications but results remain contradictory. We review the infectious risks associated with blood transfusion and the most recent data on its immunologic effects, specifically on cancer recurrence, mortality, and postoperative infections in surgical patients. We also review the use of leukoreduction in blood transfusion and its role in preventing transfusion-transmitted infections and immunomodulatory complications.

Elevated serum transaminase values during therapy for acute lymphoblastic leukemia correlate with prior blood transfusions

Fifty-nine children treated with acute lymphoblastic leukemia (ALL) were evaluated for abnormalities of liver function in order to monitor chemotherapy-induced hepatotoxicity. Twenty-one patients (36%) had elevations of alanine aminotransferase (ALT) in a pattern consistent with either drug-induced hepatocellular injury or non-A, non-B (NANB) hepatitis. These 21 patients (Group 1) were compared with the other 38 children (Group 2) with regard to a number of clinical and laboratory characteristics. Patients in Group 1 were older (P = 0.002) and had lower platelet counts (P less than 0.001) and hemoglobin values (P = 0.075) at diagnosis than Group 2 patients. The median number of units of blood products transfused was significantly greater in Group 1 patients (9.0 versus 1.0 units, P less than 0.001). The two groups were similar with regard to chemotherapy regimens. Children with ALL who present at an older age and who have more marked anemia and thrombocytopenia require more blood transfusions and are more likely to develop elevated ALT values in a pattern consistent with acute or chronic NANB hepatitis. These findings suggest a predominant role of NANB posttransfusion hepatitis--rather than or in addition to chemotherapy-induced hepatic injury--as a cause for elevated ALT values in children with ALL. In view of the potentially serious consequences of NANB hepatitis, a change in transfusion support practices may be warranted.

Non-A, non-B hepatitis; factors involved in progression to chronicity

A cross-sectional, longitudinal study was undertaken on a group of acute non-A, non-B hepatitis patients, as well as on a control group of hepatitis B patients, in order to assess both the prevalence of the most important factors favoring infection, and the relevance of these factors in promoting evolution towards chronic liver disease. Exposures to unknown risk factors were present in 47.4% of acute non-A, non-B infections, followed by blood transfusions (17.9%), sporadic exposures (17.9%) and drug addiction (16.6%). Unknown as well as sporadic exposures showed a greater prevalence in control population if compared to non-A, non-B cases, while drug addiction was equally represented in the two groups, and blood transfusion nearly absent from control group. The risk of evolution to chronic liver disease was about 13 times greater in non-A, non-B group than in controls, with the greatest risk for drug addicts and the lowest for patients with unknown exposures. Among patients with known exposures, the lowest risk of chronic hepatitis was observed in post-transfusion and in sporadic cases, while the greatest was observed in drug addicts.

Transfusion therapy in emergency medicine

Volume replacement is critical to the resuscitation of the hemorrhaging patient, but this usually can be accomplished quickly and safely with crystalloid and/or colloid solutions. Red cells should be used in addition to asanguinous fluids in the treatment of tissue hypoxia due to anemia. The need for whole blood as opposed to packed red blood cells is controversial. However, plasma should not be used as a volume expander, and its use to supplement coagulation factors during the massive transfusion of red cells should be guided by laboratory tests that document a coagulopathy. Similarly, platelet transfusions are indicated to correct documented thrombocytopenia or platelet dysfunction, and routine prophylaxis after fixed volumes of red cells results is unwarranted. Many anticipated complications of massive transfusions, including hemostatic abnormalities, acid-base imbalances, hyperkalemia, and hypocalcemia, are uncommon or of limited clinical significance. The risks of immune hemolysis and transfusion-transmitted diseases, on the other hand, are significant, and argue for judicious use of blood components. In emergencies in which blood is required immediately before compatibility testing can be completed, O-negative uncrossmatched blood can be requested. Careful blood specimen collection and patient identification prior to transfusion are critical. Practices that emphasize blood conservation, including the use of autologous salvaged blood, are always to the patient's advantage.