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an excess over what is normal or needed.
an excess of iron in the body. See also hemochromatosis, hemosiderosis, siderosis.
transfusion reactionBlood transfusion reaction, incompatibility reaction Transfusion medicine Any untoward response to the transfusion of non-self blood products, in particular RBCs, which evokes febrile reactions that are either minor–occurring in 1:40 transfusions and attributed to nonspecific leukocyte-derived pyrogens, or major–occurring in 1:3000 transfusions and caused by a true immune reaction, which is graded according to the presence of urticaria, itching, chills, fever and, if the reaction is intense, collapse, cyanosis, chest and/or back pain and diffuse hemorrhage Note: If any of above signs appear in a transfusion reaction, or if the temperature rises 1ºC, the transfusion must be stopped; most Pts survive if < 200 ml has been transfused in cases of red cell incompatibility-induced transfusion reaction; over 50% die when 500 ml or more has been transfused; TF mortality is ± 1.13/105 transfusions Clinical Flank pain, fever, chills, bloody urine, rash, hypotension, vertigo, fainting
Immune, non-infectious transfusion reactions
• Allergic Urticaria with immediate hypersensitivity
• Anaphylaxis Spontaneous anti-IgA antibody formation, occurs in ± 1:30 of Pts with immunoglobulin A deficiency, which affects 1:600 of the general population–total frequency: 1/30 X 1/600 = 1/18,000
• Antibodies to red cell antigens, eg antibodies to ABH, Ii, MNSs, P1, HLA
• Serum sickness Antibodies to donor's immunoglobulins and proteins
Non-immune, non-infectious transfusion reactions
• Air embolism A problem of historic interest that occurred when air vents were included in transfusion sets
• Anticoagulant Citrate anticoagulant may cause tremors and EKG changes
• Coagulation defects Depletion of factors VIII and V; this 'dilutional' effect requires massive transfusion of 10 + units before becoming significant
• Cold blood In ultra-emergent situations, blood stored at 4º C may be tranfused prior to reaching body temperature at 37º C; warming a unit of blood from 4 to 37º C requires 30 kcal/L of energy, consumed as glucose; cold blood slows metabolism, exacerbates lactic acidosis, ↓ available calcium, ↑ hemoglobin's affinity for O2 and causes K+ leakage, a major concern in cold hemoglobinuria
• Hemolysis A phenomenon due to blood collection trauma, a clinically insignificant problem
• Hyperammonemia and lactic acid Both molecules accumulate during packed red cell storage and when transfused, require hepatorenal clearance, of concern in Pts with hepatic or renal dysfunction, who should receive the freshest units possible
• Hyperkalemia Hemolysis causes an ↑ of 1 mmol/L/day of potassium in a unit of stored blood, of concern in Pts with poor renal function, potentially causing arrhythmia
• Iron overload Each unit of packed RBCs has 250 mg iron, potentially causing hemosiderosis in multi-transfused Pts
Microaggregates Sludged debris in the pulmonary vasculature causing ARDS may be removed with micropore filters
Pseudoreaction Transfusion reaction mimics, eg anxiety, anaphylaxis related to a drug being administered at the same time as the transfusion
Infections transmitted by blood transfusion
• Viruses B19, CMV, EBV, HAV, HBV, HCV, HDV, HEV, Creutzfeldt-Jakob disease, Colorado tick fever, tropical viruses–eg Rift Valley fever, Ebola, Lassa, dengue, HHV 6, HIV-1, HIV-2, HTLV-I, HTLV-II
• Bacteria Transmission of bacterial infections from an infected donor is uncommon and includes brucellosis and syphilis in older reports; more recent reports include Lyme disease and Yersinia enterocolitica Note: Although virtually any bacteria could in theory be transmitted in blood, the usual cause is contamination during processing rather than transmission from an infected donor
• Parasites Babesiosis, Leishmania donovani, L tropica, malaria, microfilariasis–Brugia malayi, Loa loa, Mansonella perstans, Mansonella ozzardi, Toxoplasma gondii, Trypanosoma cruzi
iron over·load(ī'ŏrn ō'vĕr-lōd)
Variable level of toxicity due to nonphysiologic or intolerable levels of iron within the body.
A side effect of frequent blood transfusions in which the body accumulates abnormally high levels of iron. Iron deposits can form in organs, particularly the heart, and cause life-threatening damage.
a chemical element, atomic number 26, atomic weight 55.847, symbol Fe. See Table 6. Iron is chiefly important to the animal body because it is the main constituent of hemoglobin, cytochrome, and other components of respiratory enzyme systems. A constant although small intake of iron in food is needed to replace erythrocytes that are destroyed in the body processes.
a radioisotope of iron having a half-life of 45 days; used in ferrokinetics tests to determine the rate at which iron is cleared from the plasma and incorporated in red cells. Symbol 59Fe.
absorbed iron is rapidly and tightly bound to a specific transport protein, transferrin or siderophilin, from which it is discharged at iron receptor sites in the bone marrow.
an injectable form of iron used in the prevention of iron deficiency. See iron poisoning (below).
used as an injection vehicle for iron in young piglets.
iron nutritional deficiency
is most common in piglets raised on sows kept indoors under artificial conditions. Clinical signs are pallor, dyspnea, edema of the head and a secondary diarrhea.
organic iron poisoning
see iron poisoning (below).
storage of excessive iron in body tissues such as occurs in human idiopathic hemochromatosis is not recorded in animals, but overload may occur as a result of excessive therapy.
overdosing piglets with iron compounds by mouth causes diarrhea and death. Organic iron preparations, usually dextrans, injected in piglets can cause deaths acutely, within an hour or two of injection. At postmortem examination there is myonecrosis of skeletal muscle. Deaths have also occurred within a few minutes of intramuscular injection of organic iron preparations in horses. Sudden death due to massive liver damage also recorded in newborn foals dosed orally with ferrous fumarate with or without yeast in a paste. Asymmetry of the hindquarters in pigs is also recorded as a sequel of intramuscular injections of iron. See also asymmetric hind quarter syndrome. Bore water often contains significant levels of iron and when used for fish culture in dams may cause mortalities.
a source of readily available iron for metabolic emergencies, probably located in the bone marrow.
iron storage disease
polypeptides that contain iron-sulfur centers capable of Fe2S2 or Fe4S4 stoichiometry and with standard reduction potential between NAD+ and ubiquinone. Critical components of many electron transport chains, e.g. in oxidative phosphorylation and photosynthesis.
total iron-binding capacity
the serum iron plus the unbound iron-binding capacity of the serum.
see iron turnover.
unbound iron-binding capacity
that portion of the plasma transferrin molecule that is not bound to Fe3+.
highly hepatoxic in some newborn foals when fed as a dietary supplement.