Cystic Fibrosis SlflGERU SUGIYAMA, '64
INfRODUCI'ION Cystic fibro sis, also known as Mucoviscidosis and Fibrocystic D isease of the Pancreas, may be defined as a hereditary conge.n ital disease characterized by dysfunction of many of the exocrine glands. Three main systems of the body are involved ; the respiratory tract, the digestive tract and the sweat glands. The most obvious effects are susceptibility to all types of pulmonary diseases, morphologic changes ir.; the pancreas with a deficiency of its enzymes and a high concentration of electrolytes in the sweat. The basic metabolic defect is unknown, but the secretion of an abnormal, viscid mucous by the mucous glands of the respiratory and the digestive tracts is a well known feature of the disease. In the majority of untreated cases, death occurs in infancy or childhood. However, a better understanding of this disease and its proper therapy and management has led to an increasing number of patients surviving to the second and third decades. As a result, this disease presents a challenge to the physician.
lflSTORY In 1905, Landsteiner described pancreatic lesions in a case of congenital intestinal obstruction due to meconium ileus. Thus, attention was first focused on the pancreas, but it was soon realized that severe pulmonary involvement was present in almost all of these cases. In 1938, Dorothy H. Andersen analyzed all available case records and gave the first complete description of this disease. She noted that this was a relatively common familial disease. With clinical recognition and improved therapy, and particularly with the advent of antibiotics, the clinical picture and the life span of these patients was improved . More recently, abnormality of secretions of sweat and salivary glands, and cirrhosis of the liver have been recognized.
ETIOLOGY AND INCIDENCE Anderson and Hodges have claimed that Cystic Fibrosis appears when a recessive gene is present in the double or homozygous condition. This finding has generally been accepted and confirmed by Lowe, May and Reed. It is estimated that one in thirty individuals of the Caucasian races carry this recessive gene. The likelihood of the occurance of both parents being carriers is 1/30 jANUARY,
1963
x 1/ 30 or one in nine hundred marriages. Statistically at least, of every four children of such parents, one will have the disease, two will be symptomless carriers and one will neither carry nor have the disease. The incidence of Cystic Fibrosis should be 1/ 900 x 1/ 4 or one in 3,600 live births. Clinically, however, various reports indicate a greater incidence ranging from 0.7 to 2.03 cases per 1000 live births. This disease occurs mainly in the Caucasian races. It is seldom found in the Negro race and is excessively rare in the Oriental races.
PATHOGENESIS This disease affects a number of glands and organs in a variety of ways. It seems apparent that the abnormal function and structure of many tissues is probably secondary to abnormality of the mucus. It is now generally believed that the pancreas is damaged by obstruction of its ducts by abnormally viscid mucus. However, the abnormal salt loss in the sweat and parotid saliva has suggested that the basic defect does not lie only in the molecular structure of muco-protein of the body, but that the metabolism of a variety of exocrine glands is abnormal in some as yet unknown and more fundamental way. Efforts are still being made to find such a single primary basis for the disease. 1