Hyperemia of all the structures of the bone, periosteum, osseous tissue, cartilage and marrow, is the first step in the development of the rachitic lesion. As a result, we have proliferation of cartilage cells, retarded and irregular development of bone, softening of matrix, undue vascularity of the cancellous tissues, and weakness and deformity of the bones in various parts of the body.
The weight of the bones is lessened. The vascularity of the bones is increased. In some cases the blue discoloration due to the increased vascularity may be seen even through the thick scalp. Outside of the bones they may find blurring of striation of muscles, excessive fat in connective tissue between the muscle fibre and rare cases of fatty degeneration of the muscle fibres themselves. The liver is occasionally enlarged the spleen more rarely so.
Rickets is the deficiency of vitamin D in the food ingested (this containing an excess of cereals but insufficiently of milk, butter and eggs) or want of adequate sunlight necessary for the absorption retention of an adequate quantity of calcium and phosphorus for bone formation. A high carbohydrate diet may cause rapid muscular growth but without an adequate vitamin D, calcium and phosphorus the skeleton may not keep pace with it and this may cause deficient bone formation.
Rickets is a condition of disorganized ossification: the ends of the long bones show excessive proliferation of the cartilage cells but these are arranged irregularly and not in regular columns. This causes a broad bluish area with thickening of the epiphyses. The vascularity of the area is increased and inspite of good preparations, whatever bone is formed is soft and calcification is defective. The periosteum is thickened and the marrow congested.
On account of the over growth of osteoid tissues, certain areas show “bossing”. Such areas are distal ends of the radius at the wrist, junction of the ribs with the cartilages on the sternum and the frontal and the parietal bones. The imperfectly calcified, soft bones bend when any weight is imposed on them causing deformities.
What are the causes of the rickets?
Heredity is a frequent predisposing cause.
Poor nutrition, poor housing facilities, want of cleanliness, want of sun light are both predisposing and exciting causes.
Age plays a great part. Rickets is a disease of young children, starting at the age of sixth month or after, less commonly of adolescents, characterized by deficient bone formation. There is abundant formation of osteoid tissue but inadequate calcification.
Climate also has its influence, more prevalent in moist than in dry climates. Diathetic influences are second only to heredity. In the tropic the skin is more exposed to sunlight and severe forms of rickets are not usually seen.
Rickets may be associated with chronic renal insufficiency. Probably the kidneys failing to excrete, phosphorus passes into the bowels where it retards the absorption of calcium. Hypocalcaemia that follows causes hyperactivity of the parathyroid: this leads to deflection of calcium from the bones.
Signs and symptoms of rickets
The family history may show syphilis, tuberculosis or some other diathesis. The condition of the mother before and during gestation may be that of over work, prolonged lactation; improper diet, or want of exercise etc. The general surroundings have been poor.
Symptoms are slow in onset; the deficiency must be of several months to cause manifestations. In the beginning these are restlessness, irritability and sweating of the head at night, more marked in the winter and spring.The symptoms first presented by the patient are generally referable to the digestive organs, viz, in the unnatural appetite, the abnormal stools, the enlarged abdomen, etc., followed by loss of weight.
Then the patient becomes dull, listless, easily tired, inactive, emaciated or flabby. Next may be an unhealthy skin, giving us profuse offensive perspiration etc.
Digestive disturbances as flatulence and diarrhoea are common. Muscles are weak and flabby and the ligaments loose
On account of softening of the bones and consequent bending of the spine and lowering of the diaphragm the abdomen is protruded and the liver and the spleen are palpable, and somewhat enlarged also.
The later symptoms, effects, the results of the disease usually make their first appearance in the thorax. They are nodules easily palpated and readily seen in the ribs with the cartilages and are due to proliferation of cartilage cells. These are not only the first, but the most prominent results of the disease.
The child should be breast fed up to the 9 th month when weaned and put on to the good cow’s milk or good brand powdered milk having an adequate amount of vitamin D. the foods of the nursing mother also must have adequate vitamins. The food must contain a plenty of fresh milk from a cow fed on green grass, also butter, cream and yolk of egg but not any excess of carbohydrate.
Plenty of sunlight, fresh air and muscular exercise are essential.