A child from a small village from bihar has long bone pain, is weak and lethargic and on examination he has bow legs. The X-Ray reports shows increase in bone density, osteophytes and dismorphic joint space. Diagnosis:

Ans. (a) FluorosisRef: Maheshwari 5th ed. / 314* Hint in the question is child from a village of Bihar with Genu varum/bow legged, long bone pain and X-Rays showing increased bone density, this characteristically focuses towards Fluorosis.* If its genu valgum (knock knee) then answer is Rickets,GENU VALGUM (KNOCK KNEE)* It is abnormal approximation of knees with abnormally divergent ankles. It can be estimated by measuring the distance between the medial malleolis, when the knees are touching with the patella facing forwards; it is usually <5cm. Valgus alignment of lower extremities is normal in child between 2-8 years of age (Known as physiological valgus & is maximum between 2-4 years). The commonest cause of genu valgum (knock knee) is idiopathic > rickets.GENU VARUM (BOW LEGS)* Knee are abnormally divergent & ankles approximated. B/L bow legs can be estimated by measuring the distance between the medial malleoli when heels are touching; it should be <6cm. Normal children show maximum varus at 6 months to 1 year of age. The causes of genu varum are similar to genu val gum except that the defective growth is on the medial side.FLUOROSIS* Fluorine in very low concentration- 1 part per million (ppm) or less is used to reduce the incidence of dental caries. At slightly higher levels (2-4 ppm) it may produce mottling of teeth.* In some parts of India & Africa, where fluorine concentration in the drinking water may be above 10 ppm- chronic fluorine intoxication (flurosis) is endemic and results in skeletal anomalies.* Characterstic pathological feature is subperiosteal new bone accretion and osteosclerosis (increased bone density), most marked in vertebrae, ribs, pelvis, forearm and leg bones, together with hyperostosis at the bony attachments of ligaments, tendons and fascia.* Despite the apparent thickening & density of skeleton, tensile strength is reduced and the bones fracture more easily.* First clinical manifestation is usually a stress fracture, back pain, bone pain, joint stiffness and neurological defects ( due to hyperostosis encroaching vertebral canal).* Characterstic x- ray features are osteosclerosis, osteophytosis and ossification of ligamentous and fascial attachments. It can be radiologically mistaken for other osteosclerotic conditions as Paget s disease, osteopetrosis, renal osteodystrophy, idiopathic skeletal hyperostosis etc.* NOTE: Fluorine stimulates osteoblastic activity; fluoroapatite crystals are laid down in bone and these are usually resistant to osteoclastic resorption. This leads to calcium retention impaired mineralization and secondary hyperparathyroidism.Also Know* Infantile cortical hyperostosis (Caffeys Disease) is a self limiting disorder characterized by soft tissue swelling, rapid subperiosteal new bone formation, cortical thickening of under lying bones, fever and irritability. Classically, the onset of disease occurs before 5th month of life with resolution by 3 years of age.* In sporadic cases, mandible is the most common site of involvement presenting as jaw tumor or swelling i.e. is firm, tender without heat or redness.