Filariasis is a tropical disease caused by Wuchereria bancrofti or Brugia malayi. Blood-sucking insects like mosquitoes and blackflies transmit the disease. Traditionally, the diagnosis of filariasis is suspected when there is an increase in eosinophils in blood. Diagnosis is confirmed using a microscope to identify microfilariae in blood smears.
Microfilaria is an early stage in the life cycle of parasitic nematodes.The adults live in tissues and in the circulatory system, releasing microfilariae into the bloodstream only occasionally. So often, microfilariae are not detected in blood.
Filarial infections may remain asymptomatic in many cases. But in some, the infection may lead to lymphatic blockade and elephantiasis.
Though the most common manifestation of the disease is elephantiasis of the legs, the lymphatic blockage can lead to painful swelling of other extremities.
In some cases, microfilariae can infect the kidney too. The kidneys act as filters to remove wastes from blood and to balance electrolytes. Filarial infection in the kidney is painful. Reddish or milky white urine is seen in such cases. Unfortunately, since the condition is not well known, most doctors misdiagnose the problem.
Recently, Arvind Ahuja and team from the Ram Manohar Lohia Hospital in Delhi, reported two such difficult-to-diagnose cases. The patients presented a diversity of symptoms. In one the urine was milky white while in the other, the urine was tinted red. In one, urine was slightly alkaline, while in the other it was acidic. Absolute eosinophil count in both were within the normal range. Ultrasound examination showed no pathological changes in both patients.
So, Arvind Ahuja, Swasti Shubham and Minakshi Bhardwaj performed an ultrasound imaging of the kidney biopsies of both patients.
Microfilaria was detected in the glomerulus segments, the filtration sub units of the kidney, in the patient with milky urine.
The microscopic observations of the biopsy samples revealed microfilaria with sheath and nuclear columns in the capillary feeding the glomeruli. After careful examination, the team diagnosed the case as filariasis leading to hematuria. After medication and a follow up for one month, both patients reported improvement.
The doctors caution that such varied manifestations of filarial infection make clinical diagnosis difficult. The diligent screening of kidney biopsy sections, indispensable for proper diagnosis, especially in endemic areas, remains a challenge.
Hmunshel Jasha, North-Eastern Hill University