Congestion of the Spinal Membranes.
The blood-vessels of the spinal membranes communicate freely with the general circulation, and there is less opportunity for their obstruction than in the case of the meninges of the brain. Hyperæmia of the dura and pia mater is therefore seldom met with, except in connection with disease of the cord; and, indeed, but little is known on the subject, which is only alluded to as possible by authorities of the present day, although the affection was formerly supposed to be a common one, giving rise to various symptoms, such as numbness and formication of the extremities, muscular weakness, and even paraplegia—symptoms which are now known to be caused by structural diseases of the cord only. As Erb1 remarks, “It is hardly possible that any considerable hyperæmia of the meninges should exist without a similar condition existing in the cord also, as the vascular supply of both is the same.”
1 “Krankheiten des Rückenmarks,” von Wilhelm Erb, in Ziemssen's Handbuch, Leipzig, 1876; Am. trans., vol. xiii. p. 99.
ETIOLOGY.—Hyperæmia of the spinal membranes is found after death from convulsions, especially in cases of tetanus, hydrophobia, eclampsia, strangulation, poisoning from narcotics, etc., in which the effect is evidently due to asphyxia. An interesting case of extensive hyperæmia of the spinal membranes, as well as of those of the brain, complicating mania, is reported by M. R. G. Fronmüller.2 A girl of eighteen years, previously well, being accused of theft, fell into a state of melancholia, passing into mania, with frequent convulsions, screaming, etc. There was no spinal tenderness. The urine contained no albumen. The temperature was never elevated. No opisthotonos. The sphincters became relaxed, and she died at the end of about three weeks. The dura was found to be normal, but the pia mater of the brain, cerebellum, medulla oblongata, and cord was strongly injected. The brain and cord were normal; no ventricular effusion. Here the meningeal hyperæmia was doubtless caused by asphyxia resulting from the convulsions.
2 See Schmidt's Jahrbücher, 1883, No. 7.
Congestion of the spinal membranes has been attributed to sudden suppression of the menstrual flow or of hemorrhoidal bleeding, and to portal obstruction, but the evidence of this is very meagre. Exposure to cold and wet, as from sleeping on the damp ground, is an alleged and plausible cause.
The SYMPTOMS attributed to hyperæmia of the spinal membranes are pain in the back extending to the legs, with numbness and tingling of the toes, sensation of weight in the limbs, muscular weakness, appearing suddenly without fever and usually of transient duration. There is no evidence that it gives rise to paralysis. Considering that temporary congestion of the membranes must occasionally happen from convulsions, as in epilepsy, etc., it is remarkable that no symptoms attributable to it have been observed under these circumstances.3
3 See Epilepsy and other Chronic Convulsive Diseases, etc., by W. R. Gowers, M.D., London, 1881, p. 106.
MORBID ANATOMY.—We must be careful not to mistake post-mortem staining of the tissues from imbibition of the coloring matter of the blood—the result of decomposition aided by the position of the body—for true congestion. The latter is recognized by fine vascular arborization covering the surface of the dura or pia, often accompanied with small punctate hemorrhages. More extensive extravasations in the connective tissue, surrounding and between the membranes, are sometimes found. The spinal fluid is usually increased in amount, and often tinged with red. On account of the free vascular connection between the membranes and the cord the latter almost always partakes of the congestion.
DIAGNOSIS.—From what has been said it follows that simple hyperæmia of the spinal membranes can hardly be distinguished from that of the cord. (See the article on DISEASES OF THE SUBSTANCE OF THE BRAIN AND SPINAL CORD.) When the symptoms are unaccompanied by fever, are of very moderate severity, and of short duration, we may perhaps infer that the lesion is confined to the membranes.