Protozoa of the Digestive and Urogenital Tracts 559 



pulmonary circulation. Other secondary invasions have been reported in 

 the skin (56), lymph glands (96), bone marrow (102), brain, spleen, and 

 urinary bladder. Inflammation of the uterus and vagina, with a bloody 

 mucous discharge containing E, histolytica (123), and invasion of the 

 uterine submucosa (142) have also been reported. 



Various types of primary amoebiasis 



Although some workers still favor the theory that in the asympto- 

 matic individual, E. histolytica lives in the lumen of the colon as a com- 

 mensal (117), there is justification for the opinion that even the "carrier" 

 does not escape at least some damage to the tissues (39, 41, 58, 82). There 

 is still no conclusive proof that E. histolytica can live in the human colon 

 without actual invasion of tissue. The status of the so-called small races, 

 which are often believed to have little tendency to invade human tissues 

 (146), remains indefinite in spite of the fact that the small races have not 

 been found in the more severe types of intestinal amoebiasis. The spon- 

 taneous transformation of a small race into a large race (122) has added 

 to the uncertainty. 



In patients with symptomatic primary amoebiasis, various degrees of 

 severity may be recognized. Many cases are mild in character, others show 

 recurrent diarrhea in addition to symptoms seen in mild cases, and typical 

 amoebic dysentery occurs only in the more severe cases. 



The characterization of mild cases, as seen in various geographical 

 areas (26, 27, 40, 41, 125, 145), stresses the variety of symptoms and the 

 confusing clinical picture. Boyers (26) has encountered more than 1,900 

 complaints in about 700 patients. One very common feature is fatigability, 

 which may develop into a condition of chronic fatigue. Constipation, 

 either recurrent or chronic, is usually more common than diarrhea. Other 

 symptoms include dull headaches, nervousness, irritability, sleepiness 

 during the day, restlessness, aches in the muscles or in the regions of the 

 joints, abdominal distention by gas, "chronic indigestion," and other 

 obscure digestive disturbances. The clinical picture sometimes suggests 

 chronic appendicitis. 



In the diarrheic type, recurrent and sometimes prolonged attacks of 

 diarrhea accompany many of the symptoms present in mild cases. 



In amoebic dysentery the stools contain appreciable amounts of blood 

 and mucus. Bowel movements may range from five "or six to 30 or more 

 per day, so that loss of weight and dehydration become extensive in 

 severe cases. A mild fever may develop, and various symptoms of the 

 diarrheic cases often appear in aggravated form. The onset of acute 

 amoebiasis may be sudden in individuals with no previously recognized 

 symptoms, or there may be a gradual transition from a mild or diarrheic 

 case to typical dysentery. Various complications arise if E. histolytica 

 becomes established secondarily in the liver or other organs. 



