Other Bone Diseases: Achondroplasia, Osteogenesis Imperfecta (Fragilitas Ossium), Bone And Joint Tuberculosis

This is the commonest inherited disorder of bone and cartilage. It is transmitted as autosomal dominant. Some cases arise as mutations. It presents as disproportionate dwarfism characterized by normal trunk and short limbs (circus dwarfs). Face appears small, the skull vault is normal but the base is shortened. Other features are lordosis, wadding gait, large and flat feet and diverging fingers of equal length (trident hands). In general, the muscles are well developed and some of the joints appear stiff, but are not painful. Complications include premature osteoarthrosis involving the weight-bearing joints, spinal stenosis and hydrocephalus.

This is a generalized connective tissue abnormality inherited as an autosomal dominant, manifesting as a peculiar brittleness of the bones, making them vulnerable to recurrent pathological fractures. There is defective formation of osteoid with associated osteoporosis but the process of calcification is essentially normal. Two groups have been recognized. In some cases, the disease manifests in utero with the birth of a severely affected baby with multiple fractures. The baby may die in utero or soon after birth. The other group manifests later in life- osteogenesis imperfect tarda. Severe skeletal deformities result from the softening and bending of bones under stress or following repeated fractures with excessive callus. Bowing of long bones, kyphoscoliosis, pectus excavatum and bulging of the calvarium are some of the common deformities. Fractures may remain without union and give rise to pseudojoints. The sclera show a characteristic blue colour due to thinning. Bruising of the skin and laxity of ligaments and joints are commong. Wound healing and scar formation are imperfect. Treatment is symptomatic.

This is common in India in particular. Bone tuberculosis is generally secondary to established tuberculosis in other parts such as lungs, lymph nodes or Kidneys. The organisms reach the synovium or subchondral bone by hematogenous or lymphatic spread. In the vast majority of cases, a single large joint like the hip or knee is affected. Involvement of the vertebrae is common. In addition to the general symptoms of tuberculosis, severe local pain and restriction of movement of the affected region occur. If left untreated, the joint may be destroyed. Tuberculosis of the vertebrae leads to cold abscess formation and compression of the spinal cord. This is a frequent cause of paraplegia in India.

Diagnosis: Strong clinical suspicion is necessary for making early diagnosis. X-rays show peri-articular osteoporosis and soft tissue swelling in the early stages. Later, there is narrowing and irregularity of joint space and erosion of the cartilage and subchondral bone. The Mantoux test is often strongly positive. X-ray of the affected joint and synovial biopsy help in confirming the diagnosis.

Treatment: Vigorous systemic antituberculous therapy combined with local immobilization and other surgical measures help in bringing about a cure in most of the early cases.

Bone And Joint Involvement In Hematological Disorders

Several hematological disorders may present with bone and joint symptoms. Unless these are borne in mind, the primary condition may be missed.

Leukemias: In acute lymphatic leukemia, arthralgia, arthritis and bone pains are common. These may be mistaken for rheumatic fever or rheumatoid arthritis.

Secondary gout is common in all forms of leukemias either in the florid stage or this may be precipitated by treatment.

Allergic purpura: Joint manifestations are characteristically seen in Henoch-Schonlein purpura. Large or small joints may be affected.

Sickle Cell Anemia: Involvement of finger joints and other peri-articular tissues and severe bone pains are common during crises.

Hemophilia And other coagulation defects: Bleeding into weight- bearing joints is common. The knees, ankles and elbows are frequently affected. In the early stages, a primary joint disease may be suspected. Later, due to recurrent bleeding, the joint is damaged and ankylosis results.

Multiple Myeloma: This disorder commonly presents with bone pain and fractures, especially in the axial skeleton. It may also lead to secondary gout.

Malignant Lymphoma: This disorder may involve bones directly or indirectly by given rise to secondary gout.