Besides chylous hydrocele we may have a chylous ascites or a chylous diarrhoea. Where there is no obstruction to the thoracic duct there is less fat and the condition is more properly a lymphocele rather than a chylocele. The same distinction is applicable to the other conditions connected with lymphatic varices due to lymphatic obstructions other than that of the thoracic duct.
Laboratory Diagnosis
The blood from a needle prick of the finger tip or the lobe of the ear can be examined as a fresh preparation. It is advisable to make a vaseline ring around the drop of blood on the slide and then apply a cover-glass. Such a preparation will permit of the examination of the living embryos for a day or more.
Smear preparations may be made by the Ehrlich method of drawing cover glasses apart or by the Daniels method on slides. Some prefer making a thick smear of a drop of blood and, after it has dried, carefully to dehaemoglobinize it with water and then staining with dilute haemotoxylin. Staining with Leishman’s or Wright’s stain gives beautiful pictures. Fixation with methyl alcohol or with heat, by burning off a film of alcohol, and then staining with Giemsa’s stain or some haematoxylin preparation, is to be recommended. On the whole I consider haematoxylin the most desirable staining reagent, as such preparations hold their color for a long time. The paper-like sheaths are seen as if twisted about the larvae with their violet-stained cells. One should note a break in the violet-stained cell column which is 50µ from the head end of F. bancrofti and 40µ for L. loa.
A V spot is seen posterior to the break in the cell column and shows best with very light staining.
The break in the column of the cell nuclei marks the position of the nerve ring, which is distant from the head one-fifth the total length. The anterior spot, below the break in the cell column, is distant about 30% of the total length. It is the location of the excretory pore. In F. bancrofti the cell nuclei extend to 95% of length, thus differing from those of L. loa, which fill up the tail end. At about 82% of the length from the head is located the anal pore.
Ruge’s thick film method for malarial parasites gives excellent results in staining filarial embryos. Either the Giemsa or haemotoxylin staining may be employed.
Embryos may be found in the lymph from varicose groin glands or in the exudate from a chylous hydrocele, as well as in the urinary sediment from a case of chyluria.
The failure to find embryos in no way negatives the existence of a filarial infection.