Dr Ira Shah
M.D, DNB, DCH(Gold Medalist), FCPS

A 6 years old male child born of third degree consanguineous marriage presented with blindness since 9 months of age and frequent fractures involving both upper and lower limbs since 4 ½ years of age. He had a chronic discharge from the lower left leg since 6 months. Other siblings (3 sisters and 1 brother) were all normal. On examination he had proptosis with absent light reflex and blindness in both the eyes. Funduscopy was suggestive of optic atrophy. He had multiple limb deformities and a discharging sinus from the left lower limb. He had no primary or secondary teeth. He had pallor and massive splenohepatomegaly. Other cranial nerves were normal.

In view of multiple fractures, blindness and splenohepatomegaly a differential diagnosis of storage disorder or osteopetrosis was considered.

His hemoglobin was 9.4 gm/dl with normal WBC and platelet count and increased reticulocyle count (10%). He had hypocalcemia (S. Ca+= 4.3 mg%) with normal phosphorus and alkaline phosphatase. X Ray of the left lower limb showed old healed fracture in the upper third of tibia and fibula with lytic lesion on lower third of fibula with discharging sinus and bone in bone appearance suggestive of osteopetrosis with chronic osteomyelitis (Figure 1). He was treated with IV antibiotics for the chronic osteomyelitis and advised regarding surgery and curettage for the same. Bone marrow transplant was advised for osteopetrosis but the patient was unaffording for the same.

Osteopetrosis is a genetic disorder characterized by generalized increase in the skeletal bone density. Nine forms have been described.

Osteopetrosis with precocious manifestations – It is an autosomal recessive condition and presents in newborns leading to death at early age. It is characterized in the first few months of life with failure to thrive, malignant hypocalcemia, anemia, thrombocytopenia and fractures. Hyperostosis crowds the marrow cavity leading to extramedullary hematopoiesis and hepatosplenomegaly. Recurrent infections may occur due to defect in macrophage killing of bacteria. Blindness may occur due to bony encroachment on the optic foramina leading to optic atrophy and blindness. The X- Rays are diagnostic with findings showing generalized increase in bone density with defective metaphyseal modeling and a “bone in bone” appearance most marked in the vertebral bodies and loss of demarcation between the cortical and medullary cavity. Treatment consists of bone marrow transplant. Interferon gamma on long-term basis may also be useful. Prednisolone may be useful to prevent progression of anemia and thrombocytopenia. Oral cellulose phosphate and low calcium diet may be useful. For patients with blindness neurosurgical unroofing of optic foramina may be tried.

Osteopetrosis Tarda (Albers - Schonberg disease): It is an autosomal dominant condition and presents in late childhood as fractures, mild anemia or osteitis. It is characterized with increased density of cortical bones. Management consists of treatment of fractures and infections, periodic vision testing and transfusion/splenectomy for anemia.

Other intermediate forms and a type of osteopetrosis with renal tubular acidosis with cerebral calcifications have also been described.