Patients suffering from kidney disease bear extremes of cold and heat very badly. In cold weather the fact that the blood is driven from the surface of the body lessens the excretory function of the skin, and this throws the work of this important organ, so helpful an auxiliary in excretion, back upon the kidneys. Besides, congestions of internal organs are not infrequent during cold, damp seasons, and these bring on exacerbations of previously existing ailments that may make fatal complications. In summer intense heat leads to many more changes in the tissues, and so provides more material to { 139} be excreted than in temperate weather. Patients picked up on the street, then, at such time, will usually be found to be suffering from kidney disease. Though in profound coma, such patients seldom die without recovering consciousness. Not infrequently, after the primary stroke of the coma, there is, in an hour or two, a period in which the patient becomes almost completely rational. This period of consciousness does not last long, in many cases, and should be taken immediate advantage of, yet without unduly disturbing the patient.
There is a well-known tendency in kidney disease to the production of oedema, that is, to the outflow of the watery constituents of the blood into certain loose tissues of the body. This is easily recognised, and constitutes a valuable sign of kidney disease in the swelling of the eyelids and of the feet, that occurs so often in patients suffering from kidney trouble. The usual rule is, if the oedema begins in the face, it is due to the kidneys; if in the feet, to the heart. The cause in the latter case is the sluggish circulation due to the weakness of the heart muscle, which delays the blood so long in the extremities that its watery elements find their way out into the tissues. In kidney disease this tendency to oedema constitutes a distinct danger that may involve sudden death in certain affections. In patients suffering from kidney disease any acute sore throat involving the larynx and causing hoarseness may be followed by what is called oedema of the glottis. This is often fatal in a very short time. The glottis is the opening between the vocal cords through which respiration is carried on. This opening is but small, and swelling of the surrounding tissues readily encroaches upon it, and soon causes difficulty of breathing. If the swelling is not relieved without delay, death takes place from asphyxiation. This was probably the cause of death in George Washington. In almost the same way any acute affection of the lungs that occurs in a patient suffering from kidney disease may be followed by oedema of the lungs. The outflow of serum from the blood vessels into the loose tissues of the lungs so encroaches upon the space available for breathing, and at the same time so reduces the elasticity of lung tissue, that { 140} respiration becomes impossible, and death takes place in a few hours. This is often the cause of unexpected death after operations. The kidney affection in the patient is so slight as to have been unsuspected, or to have been considered of not sufficient importance to render the operation especially dangerous.