Epidemic dropsy is a clinical condition characterized by edema of the ankles, vascular changes, cardiac insufficiency, gastro intestinal disturbances, renal failure and glaucoma. It generally occurs in epidemic form and is due to consumption of edible oil contaminated with oil of the Mexican Poppy (Argemone Mexican).
The Epidemic dropsy disease is mainly confined to India though some cases have also been reported from Mauritius, Fiji, South Africa, Burma and Australia. In India, it is widely prevalent in places where mustard oil is mainly used as cooking media. First case of epidemic dropsy was detected in Calcutta in 1877. Subsequently they have occurred in Bihar, Bombay, Pune, Andhra Pradesh, Vidarbha, Itarsi (M.P) Delhi, Rajasthan and Gujarat.
Mustard oil contaminated with Argemone oil is the main offending agent and it is toxic alkaloid Sanguinarine and Dihydrosanguinarine contents of the oil which produce wide spread damage of capillaries (dilatation and increased permeability) in the body.
As mustard and argemone seeds look alike it is easy to mix them. Similarly it is easier to mix argemone oil with mustard oil since both have similar tastes. To produce clinical features of the disease at least one percent of argemone oil must be adulterated with mustard oil.
It is not only the consumption of adulterated oil but even massage of skin with such oil can produce the disease. It is primarily a disease of poor low socio-economic group whose diet is deficient in proteins.Often many members of the same family suffer at the same time.
Pathogenesis of Epidemic dropsy
The exact pathology of various changes in various organs is not well under stood except for that toxic substances found in argemone seeds (Sanguinarine and Dihydrosanguinarine) produce acute generalized vasodilatation and increased permeability of capillaries and small vessels mainly of heart, skin and uveal tract. Heart muscle does not show degenerative changes but there is thinning of the muscle walls.
All these changes are related to increased levels of histamine and PGE2. Subsequent to vasodilatation, small pedunclated tumours (Sarcoids) may develop and lead to bleeding. Toxin produced vascular changes lead to transudation of fluid into the subcutaneous tissues leading to production of pedal edema as well as skin changes. This is further facilitated by malnutrition and hypoproeinaemia.
Renal failure results due to glomerular congestion and patchy tubular necrosis as well as cloudy swelling of convoluted tubules. Vascular dilatation in the iris and ciliary body leads to increased intra ocular tension, glaucoma and blindness from optic atrophy.
Autopsy findings in cases of biopsy include intense congestion and edema of cardiac muscle, portal congestion, thrombosis of tributaries of portal vein, fatty degeneration and necrotic patches in liver.
Clinical features of Epidemic dropsy
The disease mostly occurs in epidemic form but sporadic cases may occur especially in endemic areas. Persons of all ages are affected though children below the age of 2 years and nourished on breast milk are not effected. Incubation period after taking the adulterated oil ranges from 10-23rd day. Onset of the disease may be acute subacute or chronic.
The most striking presentation is bilateral pitting edema in both the lower limbs. It is accompanied by redness tenderness and burning sensation which along with parasthesia may precede edema.
In majority of cases gastro intestinal symptoms such as Diarrhea, vomiting, anorexia are the early symptoms and may precede edema. Low grade fever, Breathlessness on exertion and pulmonary congestion are other features.
Cardiac involvement of varying degrees is present. It results in wide pulse pressure dilated cardiomegaly and apical systolic murmur due to functional mitral incompetence and congestive cardiac failure.
A soft tender liver may be seen in small percentage of cases. Bleeding tendency, falling of Hair, ecchymotic patches, impotence, and in women, abortions, miscarriage and still births are other features.
Eye changes are late feature and include diminution of vision, seeing colored halos, retinal venous dilatation and congestion leading to progressive retinal damage. Glaucoma occurs in 12- 15% of patients after 4-6 weeks of acute stage. It is usually bilateral, hyper secretory and open angle and if not detected and treated early will lead to irreversible blindness.
Hematological investigations shall reveal anemia which is a constant feature and is due to bone marrow depression ESR is elevated. Plasma pyruvate levels are elevated and serum proteins levels are decreased (Hypoalbuminaemia; reversal of albumin globulin ratio). X-ray chest shows cardiomegaly with pulmonary congestion. The electrocardiogram shows shortened P-R interval, sinus tachycardia and non-specific ST-T changes.
The occurrence of cases of epidemic dropsy in a community makes the diagnosis easy especially in the presence of classical signs of pedal edema, gastro intestinal symptoms and history of consuming adulterated oil.
Treatment of Epidemic dropsy
1. Stop consumption of adulterated oil.
2. Patient should be put on bed rest with legs elevated.
3. High protein diet with good quality nutrition be given. Antioxidants such as Vit. E, Vit. C and Riboflovin have beneficial influence. Calcium should be replaced.
4. Anti prost glandins E2 such as aspirin, Indomethacin, ephedrine. Clonidine eye solution for glaucoma. Anti histamines also show beneficial effect.
5. Corticosteroids are highly beneficial and symptoms of dropsy disappear in majority of cases during first week.
6. Lung infection be treated with antibiotics.
7. Digoxin, diuretics and low salt diet for congestive failure.
Prevention of Epidemic dropsy
It is important to detect argemone in oil and this is done by Nitric Acid test (orange and red to brown color develops if mixed with equal amount of nitric acid and contaminated oil). It detects only if contamination level is greater than 0-25%) and ferric chloride test (orange red precipitate). It is highly specific test. Besides these two tests paper and gas liquid chromatography are specific and sensitive tests.
It is variable. Heart and Kidney involvement indicates poor prognosis. Death is usually due to heart failure.