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Congenital Thrombocytopenia |  |
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Fetal and neonatal alloimmune thrombocytopenia occur when maternal antibodies are produced against a paternal antigen on fetal platelets. A group of lambs artificially reared and fed bovine colostrum had prolonged bleeding from puncture wounds from ear tag placement, subcutaneous bruising, weakness, and pale mucous membranes. All affected lambs died within 48 hr after birth. Thrombocytopenia was seen in whole blood, and platelets were markedly decreased on blood smears.
The presence of antibodies directed against platelets was suspected because the cows from which colostrum was obtained had been used in a previous experiment in which they had been immunized against sheep blood. |
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Cyclic hematopoiesis in gray Collie dogs (
Inherited Leukocytic Disorders) is characterized by 12-day cycles of cytopenia. All marrow stem cells are affected, but neutrophils are most affected because of their short half-life (usually <24 hr). Mild to severe thrombocytopenia can be seen, and excessive bleeding is a potential complication. This autosomal recessive disorder is fatal; affected dogs usually die from fulminating infections before 6 mo of age. Even dogs
that receive intense antibiotic therapy usually die by 3 yr of age with amyloidosis (
Amyloidosis: Introduction) secondary to chronic antigenic stimulation from recurrent infections. Treatment with recombinant granulocyte colony-stimulating factor was temporarily successful in alleviating the neutropenic cycles until antibodies were produced against the noncanine proteins. |
