Neurologic disorders in renal failure

Neuropsychiatric symptomatology with chronic renal insufficiency in the stage of compensated and decompensated retention. II. Peripheral nerve disturbances

80 strictly selected patients with chronic renal insufficiency with plasma creatinine values of 1.4-14.5 mg% were examined for clinical and electrophysiological signs of nephrogenic polyneuropathy. The motor symptoms complained of were cramps in 43.8% of the patients, "restless leggs" in 18.7%, muscular twitchings in 12.5%. It was emphasized that the first two symptoms do not always indicate the presence of polyneuropathy. 30% complained of paresthesias, 5% of "burning feet". The most frequent clinical finding was the impairment of vibration sense in the feet in 37.5% followed by diminshed appreciation of passive movement of the toes in 30%, weakening or absence of the ankle jerk in 23.8% and finally, weakening of the patellar reflex in 5%...

Free erythrocyte protoporphyrin level and nerve conduction velocity in end-stage renal disease

Increased free erythrocyte protoporphyrin concentrations and depressed motor nerve conduction velocities (MNCV) were observed in 45 patients on maintenance haemodialysis. Neither of these findings could be correlated with age, duration or frequency of dialysis, or the degree of uraemia present. A strong negative correlation (r=--0-53; P less than 0-001), however, existed between the free erythrocyte protoporphyrin level and the MNCV, which suggested either (a) a direct effect of iron status on nerve function, or (b) a toxic factor in "uraemia" that depresses both nerve conduction and haemsynthetase activity.

A memory defect in uremic encephalopathy

It has been demonstrated that anesthesia primarily affects the reticular activating system and psychological studies on patients undergoing anesthesia demonstrated a verbal memory defect. This study was performed in order to determine whether metabolic (uremic) encephalopathy follows the Jacksonian dissolution hypothesis and disrupts cortical function or whether it acts like an anesthetic, causes dysfunction in phylogenetically older systems and thereby produces a memory defect. Twenty-four uremic subjects were tested for memory function, language function, and intellectual function, and compared to 12 control subjects. The greatest difference between the groups was in immediate memory function suggesting that uremia probably acts in a manner similar to anesthesia (by causing dysfunction in the reticular activating system). It is postulated that poor arousal interferes with rehearsal and rehearsal is probably an important component of immediate memory.

[Correlation between sensory action potentials and vibratory perception in uremic polyneuropathy (author's transl)]

1. The sensory action potentials of the tibial nerve at the medial malleolus were studied by averaging in 51 patients with chronic renal failure treated by hemodialysis. Vibratory sense was also tested quantitatively on the dorsum of the foot with a pallesthesiometer. 2. Good correlation was found between sensory tibial nerve potentials and vibration sense in subclinical as well as in clinical uremic polyneuropathy. A biphasic potential correlated with unaffected vibration sense in 18 out of 23 patients, and impaired vibratory sense with a polyphasic response in 20 of 28 patients. Maximal nerve conduction of sensory fibres was faster (mean 37.4 m/sec) in cases with normal vibratory sense, but slower (mean 31.3 m/sec), when vibratory sense was impaired. Furthermore there was a correlation between the threshold of vibratory perception and sensory nerve conduction. 3. Sensory function, tested with conventional methods, was impaired only 5 times in 28 patients with altered vibratory perception. 4. The earlier impairment, especially of the vibratory sense, may be explained by the following neurophysiological mechanisms: a) Because of the polyphasic prolonged response of the sensory potentials, no rhythmical groups of impulses reach the central nervous system, but only a continual stream of small peaks arrives, so that vibration perception does not develop. b) A multiplication of the frequency of discharges caused by alternating firing of different sensory fibres is impossible due to the reduction of the number of axons. c) The prolongation of the relatively refractory period due to demyelinization of the surviving fibres prevents the transmission of frequent impulses. 5. Alterations of the sensory action potentials of the tibial nerve, as well as of vibratory perception tested quantitatively, are earlier signs of uremic polyneuropathy than the prolonged motor nerve conduction velocity. Since not all patients give accurate information when tests of vibratory sense are performed both methods should be applied. Physiological polyphasia of sensory action potentials and diminishing vibration perception in advanced age must be taken into account.

Preservation of peripheral nerve function in severe uremia during treatment with low protein high calorie diet and surplus of essential amino acids

Twelve patients with severe chronic renal failure (serum creatinine 7.0-27 mg %), and marked uremic symptoms on a 40 g protein diet, were treated with a caloric-rich diet containing 16-20 g protein, supplemented with the 8 essential amino acids (1.1-2.2 g N) and histidine (0.23-0.45 g N)in the form of tablets for periods between 3 and 34 months. During the treatment the serum urea-N fell, and the uremic symptoms subsided or diminished without the patient exhibiting signs of malnutrition. The nerve function was followed with quantitative and semiquantitative neurological tests (among others, determination of vibratory perception thresholds and nerve conduction times). Initially all patients but 2 had signs of neuropathy as measured by these methods. During the course of treatment no deterioration of peripheral nerve function was recorded in any of the patients, several of whom had had serum creatinine conceptrations above 15 mg % for long periods. We conclude that conservative treatment with N-poor diet in far advanced chronic renal failure may prevent the further development of peripheral neuropathy provided that adequatecaloried and essential amino acids (2-3 times the minimal requirements) are supplied. The results suggest that, in addition to uremic toxines, malnutrition is a factor of importance for the developments of of uremic neuropathy.

General surgery in patients on maintenance hemodialysis

A review of the experience with 66 patients on chronic hemodialysis who underwent 67 major surgical procedures is presented. There were 58 general surgical procedures, and nine major cardiovascular procedures including four emergency cardiac valve replacements. The preoperative, intraoperative and postoperative management of these patients is discussed as well as the morbidity and mortality encountered. It is concluded that patients on well-managed chronic dialysis will tolerate minor and major surgery well and renal failure should no longer be regarded as a relative contraindication for appropriate elective or emergency surgery.

Acute asymmetrical neuritis associated with rapid ultrafiltration dialysis

Three patients with chronic renal failure treated by haemodialysis developed acute asymmetrical sensory and motor neuropathies when ultrafiltration was induced to treat oedema. The neuropathies were characteristic of acute mononeuritis multiplex rather than uraemic polyneuritis, and we give our reasons for believing that they were not caused by toxic uraemic metabolites but by an ischaemic process due to vasoconstriction resulting from ultrafiltration.

Psychiatry in a postgraduate teaching hospital

A study is presented of 217 adults referred for psychiatric assessment from the wards of a postgraduate teaching hospital.

The pattern of referral and the disproportionate importance of disturbed behaviour amongst referrals from non-medical wards are discussed. The main diagnostic groups, namely, affective disorders, organic states, psychogenic somatic symptoms and attempted suicide, are tabulated and discussed. Complex problems of diagnosis and management were common and are considered under five headings: multiple pathology; the effects of intensive treatment procedures; language and cultural differences, and difficulties in follow-up.

It is concluded that the problems met in this specialized setting are likely to become general as intensive treatment and diagnostic procedures become more widespread.

The importance of organic reactions is stressed and their relative neglect by both psychiatrists and physicians commented on. The frequency of social precipitants of affective disorders and attempted suicide, however, is considered to emphasize the range of activities required of the psychiatrist in even the most technologically advanced centres.

Schwann cell dysfunction in uraemia

Examination of individual sural nerve fibres revealed segmental demyelination, in 10 out of 12 subjects with uraemia. Peripheral neuropathy was present in only two cases. The complex biochemical changes occurring with dialysis unmask the underlying demyelination in subjects with a latent neuropathy. This would explain the precipitation of a neuropathy in those subjects submitted for repeated dialysis. The possible correlation between creatinine retention, dialysis, and metabolic dysfunction in the Schwann cell system is discussed.

Drug intoxication and neurological episodes in chronic renal failure

Of 178 episodes of neurological derangement in 103 patients with renal failure, only about 40% were due to known causes such as hypertension or electrolyte failure. One-third were due to drug intoxication and no definite aetiology was found for the remainder. Drug intoxication is due partly to the accumulation of a drug normally excreted by the kidney and partly to a greater susceptibility of the central nervous system in uraemic patients. The prognosis is favourable.