EDEMA 159 



nerve lesion in itself is not sufficient to cause edema, but that a localized 

 edema may follow a nerve lesion provided there is a coincident disturb- 

 ance of renal excretory function predisposed to edema. Certain cases of 

 paroxysmal edema, such as have been reported by Palmer (&),, occur period- 

 ically and sometimes without evidence that any: of the general conditions 

 usually associated with edema is present. These cases are probably due 

 to functional nervous disorders. 



Milroy (1892) described a form of chronic hereditary bdema affecting 

 a large proportion of the descendants of the fiM individual known to have 

 had the condition. Since then similar instances- of familial edema have 

 been described by various authors -(for literature^ see Hope and French). 

 The edema is usually restricted "to the legs. Tie individuals affected are 

 usually otherwise healthy and, unless incapacitated by the swelling of 

 the extremities, lead long, active lives. It may be present at birth, but 

 more commonly appears at the age of puberty; the, timp bf appearance 

 being also a familial characteristic, and lasts throughout t^ie life of the 

 individual. It occurs in, and is transmitted through, both males and 

 females. In certain eases, in. addition to the chronic swelling, there are 

 acute exacerbations of increased swelling during which the Swollen areas 

 are red and painful. Constitutional symptoms resembling those of angio- 

 neurotic edema appear at this time.. There is no traceable cause for the 

 occurrence of this condition. 



Inflammatory edema is generally localized about the point of inflam- 

 mation, and is apparently due to both mechanical and chemical causes. 



PAKT II 



The Morphology and Chemical Pathology of Edema 



Morbid Anatomy. The accumulation of fluid in the tissues of the 

 body, with the clinical characteristics of edema, is as a rule intercellular 

 rather than intracellular. Intracellular accumulations do occur, under 

 normal as well as under abnormal circumstances, since the cells s,erve as 

 reservoirs for fluid, but a pathological accumulation of fluid is npt gen- 

 erally recognized as edema until the intercellular fluid increases. It is 

 the spreading apart of the tissue cells by intercellular fluids which gives 

 to the tissues the characteristic loss of elasticity. 



At autopsy fluid is found in varying amounts in the subcutaneous 

 tissues and in the body cavities, usually where it has been, demonstrated 

 clinically. In some chronic cases the fibrous elements of the skin are 

 thickened, forming brawny edema, or induration of the skin., ,In other 

 cases patches of the superficial layers of the epidermis are raised in blebs 

 or large bulla?. When the skin has actually broken down and secondary 



