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Enlarged spleen Enlargement of spleen for any reason, which is usually a manifestation of underlying disease; the only specific finding in splenomegaly is dragging sensation in the upper right quadrant; megalic spleens may reach 4.0+ kg–eg, in agnogenic myeloid metaplasia
Congestion Cirrhosis, CHF, thrombosis of portal or splenic veins
• Bacteria Brucellosis, infective carditis agents, syphilis, TB, typhoid fever
• Fungi Histoplasmosis
• Parasites Echinococcosis, leishmaniasis, malaria, schistosomiasis, toxoplasmosis, trypanosomiasis
• Viruses CMV, EBV
Inflammatory/immune-related Rheumatoid arthritis, SLE
Hematopoietic disease/Lymphoid function
• Malignant Leukemias, eg ALL, CLL, myeloproliferative disorders–eg agnogenic myeloid metaplasia, CML, multiple myeloma, polycythemia vera; lymphomas–Hodgkin's disease, NHL
• Nonmalignant Hemolytic anemia, histiocytosis, ITP
Storage diseases Gaucher's disease, mucopolysaccharidosis, Niemann-Pick disease
Etc Amyloidosis, cysts, hypersplenism, metastases, primary tumors

transfusion reaction

Blood 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
Transfusion reactions
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
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.


Infectious agents of very small size and structural simplicity, all of which are smaller than the smallest bacterium. They consist of a core of nucleic acid, either DNA or RNA encased in a protein shell. Viruses can maintain a life-cycle and reproduce only by entering a living cell and taking over part of the cell function. All living cells are believed to be susceptible to virus infection.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
References in periodicals archive ?
His research interests include viral hemorrhagic fevers, rabies, and rabiesrelated viruses.
A: Seasonal human flu viruses also came from birds, but these viruses have existed for many years.
E-mails coming into the company pass through several servers that scan for viruses, worms and malicious code, and the filters quarantine information based on key indicators, profanity and general spam.
Hackers can take control of computers and use them as "zombies" to spread viruses to other computers without the owner's knowledge.
Although it is not possible to get viruses simply by reading e-mail, unless the infected attachments are opened, the viruses are insidious in tricking recipients to do just that.
When you overeat or consume refined and bleached grains and cereals, you actually weaken your body and create an excellent opportunity for bacteria and viruses to grow.
According to the International Computer Security Association, 80 percent of viruses are macro viruses--and the numbers are growing.
The four steps to virus protection are to prevent viruses, detect viruses, eradicate viruses, and to report virus incidents.
Because schools are an excellent place for flu viruses to attack and spread, families with school-age children have more infections than other families, with an average of one-third of the family members infected each year.
Part of the problem is that standard antivirus and firewall applications cannot protect your handheld from viruses that may be introduced when you synchronize data between your computer and handheld device.
Genetic factors might account for an enhanced susceptibility to infection by certain viruses with specific tropism in cells in particular regions such as the globuli ossei.