We have already described the various irregularities presented by the febrile paroxysms and the intermissions, and no further allusion need be made to mere variations in length, severity, or number of the former. In rare cases, however, a peculiarity is presented, usually in the first intermission, which is difficult of explanation. About twenty-four hours after an apparently complete crisis, with a fall of temperature to a subnormal point, there may be a sudden and rapid rise or rebound of temperature to 104° or 105°, attended with distressing symptoms of high fever, but lasting only twenty-four or forty-eight hours. A good example of this is given in the case described [above] and Carter18 cites several examples of it terminating either in recovery or in rapid death. He asserts that examinations of the blood during such post-critical febrile rebounds invariably showed an absence of spirilla, so that in his opinion such fever must be considered non-specific. Their explanation seems difficult, since the pyrexia is too brief to be associated with any local inflammatory complication.
18 Op. cit., p. 172.
More frequent and serious is the protracted post-critical pyrexia which we have already described as modifying the interval, so as to produce a subintrant type by maintaining continuous though irregular fever until the accession of the relapse, unless cut short by death. This post-critical fever is non-specific, is unattended with spirilla in the blood, and is to be associated with the extensive irritative processes in the liver, spleen, kidneys, lungs, and other parts that are present in these grave and complicated cases. It is to be noted that the course of those paroxysms which terminate in lysis indicates that they may represent a milder type of the above process.
The peculiarities of the delirium, amounting sometimes to maniacal excitement, which attends some cases of relapsing fever, has been fully described.
Less common are the following: mental hebetude, lasting some days or even weeks after the close of the last paroxysm, or, as in a case of Carter's, gradually increasing mental feebleness, terminating in imbecility. In such cases suspicion must arise of the occurrence of some local lesion of the membranes or substance of the brain.
Partial palsy is mentioned by numerous authors as occurring during or shortly after attacks of relapsing fever. Paralysis of one or both deltoids has been noted, the latter by Cormack, who saw it continue ten days after the patient was well in all other respects. Temporary paralysis of the forearm (Douglas) or of the whole arm (Parry, Meschede) has been observed; and Parry also describes loss of power in the legs lasting for one week. In one of our cases temporary loss of power of the left arm and leg occurred, attended with such impairment of sensibility that the woman had to feel for the fingers of the left hand to assure herself of their existence. This loss of power occurred during the initial paroxysm, and gradually passed away, but she was unable to stand alone on the thirty-first day of the disease. In a case reported by Tennent19 facial palsy was developed six days after the second crisis.
19 Glasgow Med. Jour., May, 1871, p. 379.
Various explanations have been offered for these local palsies, but, as already stated (see [above]), it seems probable that they are referable to morbid conditions of the nerve-trunks, or, less commonly, of the spinal cord. It must be noted, however, that in a certain number of autopsies serious intracranial lesions are found, which are evidently the results of the attack of relapsing fever. These consist of abscess of the brain, meningitis, and specially cerebral hemorrhage. This was present in one of our cases, but Carter found copious hemorrhage in no less than 8 out of 54 autopsies, and in 5 others there were minute capillary cerebral hemorrhages. Still, in nearly all the cases of large hemorrhage we have found recorded the effusion was upon the surface of the brain, and this, combined with the absence of true hemiplegia from the forms of paralysis noted in relapsing fever, and the transient character of these palsies, makes it clear that they are not to be explained by any considerable cerebral hemorrhage. On the other hand, however, it must be admitted that an additional possible cause of them is to be found in minute hemorrhage into small areas known to govern the movements of certain groups of muscles. Again, we have had occasion to note the occurrence of both thrombosis and embolism among the lesions of relapsing fever, and it is evident that either of these accidents, if involving a comparatively small branch of a cerebral vessel in certain motor areas, might cause transient paralysis, such as has been described. Nor can we fail to see that, while such symptoms as the delirium, mania, coma, or subsequent mental impairment may receive other explanations, it is possible that they may arise from similar processes of minute hemorrhage, thrombosis, or embolism involving other parts of the brain.
The frequent occurrence of severe rheumatic pains in the muscles and joints during the course of the disease has been dwelt upon ([above]); but in some cases they persisted during the intermissions and for a considerable time after all other symptoms of disease had passed away. Occasionally they greatly retarded convalescence by interfering with exercise and sleep. These pains were mostly in the legs, and were increased by exercise, and also seemed to be influenced by changes of weather. Patients who suffered thus were also liable, after exposure or in consequence of severe atmospheric changes, to sharp attacks of similar pains elsewhere, and especially in the course of the intercostal nerves. Occasionally violent and persistent headache follows the disease, not improbably associated with changes in the membranes of the brain, although in other cases severe neuralgia occurs in consequence of the anæmia which may remain in an intense degree after the fever. Troublesome numbness and soreness of the soles of the feet and of the palms of the hands, increased by pressure, has been noted as a sequel persisting for several days or weeks.
Affections of the special senses are not rare. The most remarkable among these is the affection of the eyes, which is apt to occur far more frequently in connection with relapsing fever than with typhus or typhoid. The proportion of cases in which this sequel appears varies greatly in different epidemics. In the British epidemics of 1826 and 1843, when this form of post-febrile ophthalmia was first accurately described by Mackenzie of Glasgow, it was very frequent; and it was equally so in Finland in 1867-68, when Estlander20 again carefully studied it.