Clinical Significance of Weight Trends During Pregnancy

combined degeneration of the cord is to be retained it would appear logical to limit its use to lesions of the central nervous system, Unfortunately, even neurologists find it difficult to decide on the clinical features which clearly distinguish lesions of the posterior columns of the cord from lesions of the peripheral nerves. It is generally agreed that tendon reflexes, vibration sense, and positional sense may be reduced or absent and also that ataxia may be present in both conditions. There appear to be no infallible criteria which will distinguish the two lesions except histological examination of the affected structures. Accordingly, the differential diagnosis during life has to be made on the basis of certain suggestive findings. Thus, hyperalgesia of calf muscles strongly supports the diagnosis of peripheral neuritis, while loss of vibration sense extending up to the pelvis favours a lesion of the posterior columns. Lastly, a-iMarkedly disproportionate increase in the degree of impairment of muscle and joint sensibility and vibration sense on the one hand, as compared with the degree of loss of superficial sensations of touch and pinprick on the other, supports the view that the posterior columns are affected. The presence of an extensor plantar response (positive Babinski sign) clearly indicates that a lesion of the central nervous system is present, but it must be remembered that in pernicious anaemia the lateral columns of the cord are affected much more rarely and usually much later than are the posterior columns. It should also be noted that peripheral neuritis may be due to a specific deficiency of vitamin B1 or it may result from anoxaemia of the peripheral nerves as a consequence of anaemia and cardiac weakness. In the former case it may be present when anaemia is minimal in degree and it will respond dramatically to vitamin B12 therapy. In the latter case it may occur in association with any form of anaemia, but only if the degree of anaemia is sufficiently severe, and it will not respond to vitamin BR2 therapy, but will disappear when the haemoglobin level is raised by any method, including blood transfusion. In assessing the incidence of subacute combined degeneration of the cord in the Edinburgh series of 250 patients, cases have not been included in which the only neurological features were of paraesthesiae and the subjective sensation of unsteadiness, since both these symptoms can be due to causes other than disease of the nervous system. Patients were classified as having involvement of the posterior columns if ataxia was a prominent feature, if tendon reflexes and positional sense were reduced or absent, and if vibration sense was lost as high up as the pelvis. They were classified as having lesions of the pyramidal tract if a spastic gait was present with increased tendon reflexes, extensor plantar response, and a greater or lesser degree of paralysis. These groups are therefore comparable to the two groups described by Cabot (1908) as the " ataxic type" and the " spastic type. " Table III shows that involvement of the central nervous system was present in only 11% of Cabot's series and in 7% of the Edinburgh series. This is in contrast to the frequency of occurrence of paraesthesiae as indicated in Table II. One of the most striking features of Table III is the difference in the degree of anaemia present in the three series when medical advice was first sought. Whereas 21% of Cabot's series had a blood count of less than one million red cells per c.mm. , only 1% of the Edinburgh series had a similar degree of anaemia. Panton's series also showed a very high incidence of severely anaemic cases, the average red cell count being 1.39 million per c.mm.