Although acknowledged to be a grave complication, and the most frequent cause of death in diabetes,18 yet it does not follow that a fatal termination is inevitable when diabetic coma sets in. I have now a patient, a woman, who considers herself in perfect health, but in whom there remains a trifling glycosuria, who at one time was supposed to be dying of diabetic coma.
18 Of 400 cases of diabetes which passed under the observation of Frerichs, the majority died of acetonæmia (Frerich's "Ueber den plötzlichen Tod und über das Coma bei Diabetes," Zeitschr. für klin. Med., 1883, vi. 3-53). Of 53 persons dying of diabetes at Guy's Hospital, London, during the last ten years, 33 died comatose (Dr. Fred. Taylor, Discussion on Diabetes, Pathological Society of London, Lancet, May 5, 1883). In my own experience acetonæmia has not been so frequent a cause of death as phthisis, acute pneumonia, and heart-failure.
Crampy pains in the legs and facial paralysis are among the nervous symptoms sometimes present, and the term diabetic neuralgia has been applied to a special form of neuralgia peculiar to this disease. It is characterized by its acuteness, stubbornness, and symmetry. Its favorite seats are the inferior dental nerves and the sciatics. Greisinger referred to the frequency of sciatica in 1859, Braun again in 1868, and others still later; but Worms in 1881 established the close relation between the two conditions and the features described. Most recently (1884), Cornillon19 collected 22 cases of diabetic neuralgia, and has further elaborated the study. Believing that diabetes affects particularly those persons who have had serious attacks of rheumatism and gout, he is inclined to think the neuralgia as much due to uricæmia as to hyperglycosuria, and that these conditions cause, not neuritis, but transitory lesions in the nerve-centres, but whether in the membranes or gray or white matter is undetermined.
19 "Des nevralgies diabétiques," Revue de Médecine, 1884, iv. 213-230.
That the phenomena of acetonæmia are those of a toxic agent or agents in the blood derived from the sugar there present is generally conceded, although Sanders and Hamilton,20 after a study of the clinical histories and the result of autopsies in several cases, are disposed to ascribe diabetic coma to slow carbonic-acid poisoning due to fat embolism of the pulmonary vessels. So far as I know, these conclusions have not been reached by any other observers. R. H. Fitz21 and Louis Starr22 have each reported cases of diabetic coma with lipæmia, carefully studied with this point in view, without finding any facts to sustain the carbonic-acid theory.
20 Edinburgh Med. Journal, July, 1872.
21 "Diabetic Coma; its relations to Acetonæmia and Fat Embolism," Boston Medical and Surgical Journal, vol. cvi. p. 24, Feb. 10, 1881.
22 "Lipæmia and Fat Embolism in Diabetes Mellitus," New York Medical Record, vol. xvii., 1880, p. 477.
Alterations in the Blood.—The blood of diabetics is variously charged with sugar, which may be in such quantity as to impart a viscidity and higher specific gravity to the plasma, which has reached 1033, the normal being 1028. On the other hand, analyses have sometimes failed to discover sugar in the blood after death, the result, probably, of the tendency of the sugar to rapid disintegration. Alcohol and acetone, or acetone-producing substance (aceto-acetic acid), are occasionally present as the products of such decomposition, to which are ascribed the symptoms of acetonæmia already discussed.
The presence of fat in the blood of diabetics was noted by the earliest students of the disease. It is sometimes sufficient in amount to produce a milky appearance of the serum, while the analyses of Simon revealed a quantity of 2 to 2.4 per cent., the normal being 1.6 to 1.9 per cent. The fat thus present is said to be sometimes sufficient to cause fat embolism in the capillaries of the lungs, and cases of this condition have been reported by Sanders and Hamilton,23 Louis Starr,24 and Rickards.25 Ralfe ascribes the lactescent appearance of the blood to the action of the aceto-acetic acid, since acetic will give a milky appearance when agitated with a dilute and slightly alkaline mixture of fatty matter at 100°, and the injection of acids into the blood of animals leads to the increase of fatty matter in the blood and fatty infiltration of tissues.