Endemic fluorosis is a disease entity caused by ingestion of water containing high concentration of fluorides over long periods of time. Besides various structures it mainly involves teeth and skeletons.
Endemic fluorosis is present in many parts of India (Andhra Pradesh, Punjab, Haryana, Tamil Nadu, Rajasthan, Uttar Pradesh) and countries like China, Japan, Sandi Arabia as well as USA.
Fluoride is present in rocks from which it enters the subsoil water and humans get affected, after drinking water containing high fluoride content. It is mainly absorbed through the gastro intestinal tract. In its gaseous form derived from industrial gases it is extremely poisonous and is absorbed from the respiratory tract.
Drinking water which contains fluoride up to 0.8 ppm is considered safe. Excessive intake of it in early childhood (2.5 mg/day) results in. Dental and skeletal Endemic fluorosis with consequent crippling and neurological complications.
A number of factors influence toxicity of it. Out of these content of water is the most important and water containing it above 1. PPM has the potential risk.
Fluorides have cumulative effect and so the manifestation of skeletal Endemic fluorosis depends on the period of exposure. Moreover the concentration of it in drinking water shall also have important bearing.
Higher the concentration lesser the period of exposure shall be needed. Hard water containing calcium and magnesium has a protective role depending on the hardness of water. Nutrition especially lack of proteins, calcium and vitamin C makes people residing in endemic areas, more prone to suffer from skeletal type.
People who do hard manual labor like carrying of heavy loads on their head and shoulders, are more liable to suffer from involvement of cervical spine.
Climate also has a role in the causation of Endemic fluorosis. Thus high temperature, excessive sweating in hot and humid climates leads to excessive loss of fluids from the body and the result is that fluid intake increases and thus more consumption of it in drinking water.
Dental fluorosis is characterized by mottled enamel and is a characteristic feature of the disease in people living in endemic areas. It is one of the early, sensitive and readily distinguishable sign of excessive ingestion of fluoride in childhood.
It shall develop only if the child has lived in the endemic area during dentition phase of life. It is primarily hypoplasia with areas of hypo calcification and hypomineralization followed by pigmentary deposits on surface of teeth. It has been graded as follows:
Grade I: White chalky opacities or patches on enamel with or without faint yellow lines.
Grade II: Distinct Brown discoloration
Grade III: Besides pigmentation there is pitting of the enamel surface, sometimes with chipping of edges.
Dental Endemic fluorosis in adults differs from that in children. In some adults pigmentation of enamel is lost and is replaced by diffuse yellowish coloration. Besides these changes premature loss of teeth may occur.
It takes a fairly long time to develop and early cases remain asymptomatic till detected on radiological examination. Early symptoms include pain and stiffness of joints especially of the spine.
Parasthesia in the extremities may be another mode of presentation. Bones in body become heavier and irregular. The sites of muscular and tendon insertions become prominent by excessive periostal reaction resulting in formation of multiple exostosis.
These can be easily palpated along the anterior border of the tibia, over the olecranon, along medial border of scapula and near the spinous processes of vertebrae. Spine shows limitation of movements with calcification of various ligaments and fusion of vertebrae at many places. Patient often assumes a typical posture because of marked kyphosis and fixed flexion deformities of hips and knees.
As the anterior posterior diameter of spinal canal is reduced there may be compression of spinal cord leading to myelopathy. Neuritic pains occur because of involvement of intervertebral foramina due to osteophytes. The ossification of interosseous membrane in leg and forearm is an important sign.
Radiologically marked changes are seen in vertebral column in the form of osteosclerosis and irregular osteophyte formation. There is irregular periosteal thickening with loss of trabecular pattern and uneven bony contours.
The bones assume a chalky white ground glass appearance which is most marked in spine and pelvis. Besides beak like lipping in the vertebrae there is calcification of intervertebral ligaments. Interosseous membrane calcification in the forearm is an important radiological sign and is diagnostic of skeletal Endemic fluorosis.
Advanced stage of skeletal type results after the exposure has been for periods ranging from 10-20 years in an endemic area. There are features of radiculo myelopathy, due to compression of spinal cord and nerve roots. There is wasting, acroparasthesiae along the nerve roots of the upper limb while in lower limbs, weakness and wasting followed by parapresis I Quadriplegia may develop.
In advanced cases, renal involvement may take place since fluoride is cleared through it. There are reports also about thyroid and para thyroid functions involvement. Anemia may be seen due to depressed bone marrow function.
Fasting normal fluoride ion concentration in human serum is about 0.2-0.4 micro-moles while in cases of Endemic fluorosis it is 7-10 micro-moles. Estimation of urinary fluoride is an important investigation and has important relationship with the fluoride content of drinking water. Except for serum alkaline phosphatase which is raised in its cases other parameters like serum calcium, phosphorus and magnesium levels are within normal limits.
A florid case can be easily diagnosed from mottled teeth, kyphosis, palpable exostosis and calcification of osseous membrane along with marble bone appearance of bones (spine, pelvis).
Any person residing in area where endemic fluorosis is prevalent, signs of parasthesia, joint pains, and tingling in the limbs should make one suspect the disease.
There is no specific treatment. It is mainly preventive. Water supply with safe fluoride levels (<0.5 PPM) must be ensured by process of DE-fluoridation. For those with fully developed one, Vit C & Vit D supplementation along with low calcium diets are considered beneficial.
In addition analgesics are given for neuralgic pains. Physiotherapy is also of use. Patient should be asked to be mobile as much as possible. Nutritional requirements be looked into. Cases of spinal compression may be benefited by laminectony though the results are not very encouraging since skeletal Endemic fluorosis is a wide spread disease.