Chronic stage of filariasis usually develop 10-15 years from the onset of the first acute attack. The incidence and severity of chronic clinical manifestations tends to increase with age. The main characteristic feature of chronic filariasis is:
Great enlargement of the lymphatic glands with fibrotic changes is common in chronic filariasis.
The glands (groin glands usually but, in the Pacific, epitrochlear glands) are enlarged
to 5-7.5cm in diameter and may form permanent 'tumours'. On section they resemble an unripe
pear, the central portion being fibrotic and the peripheral, glandular. They may contain numerous
coiled up adult worms.
Varicous groin glands are frequently associated with lymph scrotum chylocele or chyluria. Then a sense of tension or an attack of lymphangitis draws attention to the area where soft swelling are discovered. These swelling may be of insignificant size or they may be as large as a fist. They may be noted on groin and affect the inguinal or femoral glands alone or together.
After the initial swelling and inflammation of lymphangitis have subsided a line of induration remains. On excising this thickened tissue and dissecting it, minute cyst-like dilations of the lymphatics have been found containing live or dead adult filariae (but this surgical treatment is not recommended)
Swelling of the distal parts of the body appears during acute attacks of filarial lymphangitis
and consists of pitting edema which at first subsides completely. After each attack edema increases
and subsides more slowly until it finally becomes permanent. The edema eventually ceases to pit and after
a period of time becomes firm.The lymphoedema of lower limb is classified into four grades.
When the skin becomes chronically thickened it can be called elephantiasis and this is associated
with hypertrophy and fibrous hyperplasia of the subcutaneous tissues.
In 95% of cases the lower extremities, either one or both, alone or in combination with the scrotum, or arms are affected. The foot and ankle only, the foot, leg and thigh may each or all be involved, and more rarely the breast, vulva and circumscribed portions of the integuments of the limbs or trunk.
The scrotum is thickened and the lymphatic varicosities, in the skin are discharging
serous serosangineous or milky fluid. Many cases have an associated inguinal or femoral adenopathy.
Pathologically it is characterized by a distended, generally thickened tunica, vaginalis with hyalinization and fibrosis of the subserosal layer, disorganization of the muscle layers, lymphoid and foreign-body giant cell infiltration, and, in extreme cases, calcification.
The hydrocele fluid itself is amber in colour and the sediment shows a characteristic predominance of vacuolated mesothelial cells, fibrin, old blood clots, cholesterol clefts, and calcium dust.
Such findings, when associated with epididymal changes, are highly suggestive of a filarial etiology for the hydrocele even without the recovery of W. bancrofti microfilariae from the fluid or adult worms from the cord and epididymal tissues.
A majority of these patients do not give any history of ADL attacks in their life time therefore, the progression seems to be a passive phenomenon.
Chyluria is a condition where the patient complains of passing milky white urine, caused by admixture of lymph with urine due the rupture of lymphatics into the urinary system.
may result in the loss of fat in the urine amounting to 15% of lymphatic drainage of the gut.
Chyluria will have the same metabloic effects as malabsorption and cause considerable loss of weight with
vitamin, electrolyte and other deficiencies.
The protein loss in lymphuria may lead to oedema secondary to hypoalbuminaemia.
Loss of lymphocytes in prolonged chyluria may lead to low lymphocyte levels which when associated with immunosuppression from drugs may encourage opportunist infections. Chyluria results in pain in the back and aching sensations about the pelvis and groins probably caused by distension of the pre-existing varix. Retention of urine from the presence of chylous or lymphatic clots may be the first indication of trouble. The patient then suddenly becomes aware that he is passing milky urine which may be pink or red; sometimes it is white in the morning and red in the evening or vice versa. Chyluria is likely to occur for the first time, or as a relapse, in pregnancy or after childbirth. The presence of blood is caused by the rupture of small blood vessels into the dilated lymphatics when microfilariae may appear in urine passed during the night time only.