Coelomic cavity effusions are classified as pure transudates, modified transudates or exudates (nonseptic, septic, malignant
or hemorrhagic) based upon cellularity, color, total protein and specific gravity. Pure transudates resulting from changes
in oncotic pressure associated with hypoproteinemias, cardiac disease or hepatic cirrhosis are characterized by a low cellularity
(total count less than 1,000 microliters), specific gravity of 1.020 or less, total protein of 3 g/dl or less, and a clear
to pale- yellow color. Modified transudates have an increased cellularity (total cell counts greater that 1,000 microliters
but less that 5,000 microliters) of mononuclear cells, granulocytes and reactive mesothelial cells, and protein content. Exudates
typically have a high cellularity (greater than 5,000 microliters), high specific gravity (greater that 1.020) and total protein
levels greater that 3 g/dl. The predominate cell type accompanying exudates may indicate the source.
Cytology of internal organs
Tissue or fluid smears, squash preparations, aspiration or excisional biopsy are methods used to sample internal organs, such
as the liver or spleen. Endoscopic or surgical laparoscopy techniques may be used to obtain samples. Splenic impressions generally
reveal a significant amount of blood cells and heavy background of cellular debris. Liver aspirates are generally very cellular
with hepatocytes in sheets or singles with a large amount of blood cells and free hepatocyte nuclei.
Bone marrow aspiration
Nonregenerative anemias, blood dyscrasias, thrombocytopenia and neoplasia of the hematopoietic and reticulo-endothelial systems
should be evaluated by bone-marrow examination. A preferred site for bone marrow aspiration in the avian patient is the proximal
tibiotarsal bone. The widest part of the sternum may also be used. Additionally, a particular area may be aspirated if indicated
by the presence of a lesion noted on radiographs. The proximal tibiotarsal bone is aseptically prepared, and a small incision
is made in the skin. A spinal needle or hypodermic needle is inserted and advanced into the cnemial crest at either the level
of insertion of the patellar tendon or perpendicular to the bone on the medial aspect. A 1 to 6-cc syringe is used to collect
the sample. The needle and syringe are removed, and the marrow sample is placed on glass slides or cover slips and gently
spread. Normal cells present in a bone-marrow aspirate include erythropoietic and granulopoietic cell lines in various stages
of development lines, as well as thrombocytes, lymphocytes, osetoblasts and osteoclasts.
Dr. Jones is associate professor of avian and zoological medicine at the University of Tennessee's College of Veterinary Medicine.
He is a diplomate of the American Board of Veterinary Practitioners — Avian Specialty. Dr. Jones' clinical interests include
raptor medicine, orthopedic and soft-tissue surgery, avian nutrition and avian infectious diseases. He is also a master falconer
with 15 years experience.