[Latent tetany in child, electrophysiologico-clinical study]

Tetany is the abnormal state of increased neuromuscular excitability. It is manifested with muscle cramps and spasms, usually associated with abnormal calcium metabolism. This state can be devided into two main types: tetany with clinical manifestaton (hypocalcemic) and occurred more frequently latent tetany (normocalcemic). In this study was presented the case of a child with electrophysiological and clinical manifestation of latent tetany. We report a case of a female patient who was admitted to the Pediatric Neurology Department in the year 2015. Some clinical, biochemical and neurophysiological results have been analyzed.

Hypokalaemic paralysis and normocalcaemic tetany--a rare presentation of Sjogren's syndrome

38 year old woman was admitted with acute onset of quadriplegia. Biochemical investigation revealed severe hypokalaemia with hyperchloraemic metabolic acidosis, alkaline urine, and positive urinary anion gap which are the hallmark of distal tubular acidosis. In addition she also had hypophosphataemia, normoglycaemic glycosuria, aminoaciduria, and hyperphosphaturia suggestive of proximal tubular dysfunction. Further evaluation confirmed the diagnosis of Sjogren's syndrome. Interestingly our patient also had carpopedal spasm despite normal calcium and magnesium level. Quadriplegia and carpopedal spasm improved with correction of hypokalaemia and acidosis. Proximal tubular abnormalities (except albuminuria) were normalised at the time of discharge. Distal tubular acidosis is a well known renal manifestation of Sjogren's syndrome. But this type of transient proximal tubular dysfunction with distal tubular acidosis in Sjogren's syndrome is very rare and hypokalaemic tetany also deserves mention.

Tetany with Plasmodium falciparum infection

Plasmodium falciparum is a malarial infection with high morbidity and wide spectrum of atypical presentation. Here we report an unusual presentation of malaria as tetany with alteration in calcium,phosphate and magnesium metabolism Hypocalcaemia in malaria can cause prolonged Q-Tc interval which could be arisk factor for quinine cardiotoxicity and sudden death Hence monitoring of serum calcium in severe malarial infection and cautious use of quinine in such patients is very important in management

[Diagnostic image. A girl with cramp and tingling of the hands]

An 8-year-old girl presented with cramp and tingling of the hands due to hypocalcaemia caused by pseudohypoparathyroidism.

Unusually high serum levels of lactate dehydrogenase without perivalvular leakage following double valve replacement: predictor of tetany attack after thyroidectomy

A 57-year-old woman who complained of exertional dyspnea was diagnosed as having severe aortic valve stenosis and mitral valve regurgitation. The patient underwent double valve replacement with a mechanical prosthesis. Postoperative laboratory data showed unusually high serum lactate dehydrogenase (LDH) levels, even though no perivalvular leakage was detected by echocardiography. Tetany occurred suddenly owing to hypoparathyroidism, which seemed to be a late complication after thyroidectomy. After calcium administration, the symptoms dramatically diminished, as did the serum LDH levels. Hypoparathyroidism should be doubted if serum LDH levels increase higher than the normal range following valve replacement without obvious perivalvular leakage.

Intraoperative Parathyroid Hormone Assay in Patients with Graves’ Disease for Prediction of Postoperative Tetany

We measured intraoperative parathyroid hormone (IOPTH) levels before and after thyroidectomy in a large group of patients to test whether changes in IOPTH can predict postoperative tetany. Subjects were 111 consecutive patients (94 females and 17 males) with Graves' disease undergoing subtotal thyroidectomy. Blood samples for IOPTH assay were obtained after anesthesia (basal) and following skin closure (postoperative). Data were compared between patients who developed tetany (n = 9) and those who did not (n = 102). There was no significant difference in sex, age, period of antithyroid drug administration, or the weight of the thyroid between the two groups. The preoperative serum calcium level was significantly lower (p < 0.05) and the basal IOPTH significantly higher (p < 0.05) in the tetany group than in the non-tetany group. The IOPTH level was significantly lower (p < 0.005) and the average percent decrease in IOPTH levels was higher (p < 0.001) in the tetany group than in the non-tetany group. A decrease in IOPTH of more than 70% was shown to be 78% sensitive, 94% specific, and 93% accurate, and it has 78% positive predictive value and 94% negative predictive value for the development of tetany. Our study shows that a postoperative decrease of IOPTH level is the most predictive of postoperative tetany of the clinical risk factors investigated. We recommend IOPTH measurement as an adjunct to postoperative management of patients with Graves' disease to assist in preventing hypocalcemia and determining the earliest time for safe discharge.

Randomized study on oral administration of calcitriol to prevent symptomatic hypocalcemia after total thyroidectomy

BACKGROUND

Symptomatic hypocalcemia remains the main postoperative complication after total thyroidectomy. The aim of the present study was to evaluate the role of oral supplementation of calcitriol and calcium salts in preventing severe postoperative hypocalcemia after total thyroidectomy.

METHODS

A consecutive series of patients undergoing total thyroidectomy followed by administration of 500 mg of calcium salts 3 times per day were randomized to 3 different postoperative medical treatments: in group A, .5 microg of calcitriol twice per day was administered to 104 patients; in group B, 1 mmicrog of calcitriol twice per day was administered to 111 patients; and in group C, 202 patients did not receive calcitriol.

RESULTS

The rate of postoperative tetany in group A was 2.9%, in group B was 0%, and in group C was 7.4% (P=.03) and the rate of paresthesias was 28.8%, 17.1%, and 22.3%, respectively (P=.19). At discontinuation of calcitriol/calcium salts treatment, intact parathyroid hormone levels did not significantly differ from the preoperative levels. Receiver operating characteristic (ROC) curve analysis showed that the area under the curve for serum concentration of calcium in predicting postoperative tetany was .749, .858 and .862 on the first, second, and third postoperative day, respectively. The best cut-off value of calcemia for prediction tetany was 7.5 mg/dL, and the rate of severe hypocalcemia on the third postoperative day was 23.1% in group A, 9.9% in group B, and 27.2% in group C (P=.001).

CONCLUSIONS

Oral administration of 1 microg of calcitriol twice per day and 500 mg of calcium salts 3 times per day after total thyroidectomy significantly decreases the risk of severe postoperative hypocalcemia.

Predictive risk factors for postoperative tetany in female patients with Graves' disease

BACKGROUND

Postoperative tetany occurs in patients with secondary hyperparathyroidism caused by a deficiency in calcium and vitamin D concomitant with transient hypoparathyroidism induced by surgery. In the present study, we further clarified the risk factors by referring to serum 25-hydroxyvitamin D [25(OH)D] and alkaline phosphatase.

STUDY DESIGN

The serum levels of intact parathyroid hormone, calcium and other electrolytes, and 25-hydroxyvitamin D [25(OH)D] were measured preoperatively in 178 female patients with Graves' disease who underwent subtotal thyroidectomy.

RESULTS

Of the 178 female patients, 15 (8.4%) developed tetany. Univariate analysis of 16 possible risk factors showed that 2 were statistically significant: serum 25(OH)D and alkaline phosphatase levels. The incidence of tetany according to the serum levels of 25(OH)D and alkaline phosphatase was 19.1% (9/47) in patients with 25(OH)D < or = 25 nmol/L and alkaline phosphatase > 155, 11.8% (4/34) in those with 25(OH)D < or = 25 nmol/L and alkaline phosphatase < or = 155, 6.7% (2/30) in those with 25(OH)D > 25 nmol/L and alkaline phosphatase > 155, and 0% (0/50) in those with 25(OH)D > 25 nmol/L and alkaline phosphatase < or = 155.

CONCLUSIONS

Patients with Graves' disease who have vitamin D deficiency with high serum alkaline phosphatase levels are the highest-risk group for postoperative tetany. Serum 25(OH)D and alkaline phosphatase should be monitored in patients with Graves' disease.

Calcium and its regulating hormones in patients with graves disease: sex differences and relation to postoperative tetany

OBJECTIVE

To find out why female sex is the most important risk factor for tetany, as calcium and bone metabolism may differ between the sexes.

DESIGN

Prospective study.

SETTING

Thyroid centre, Japan.

PATIENTS AND METHODS

45 men (mean age 35 years, SD 13) and 178 women (mean age 33 years, SD 12) with Graves disease treated by subtotal thyroidectomy.

INTERVENTIONS

Measurement of serum concentrations of intact parathyroid hormone (iPTH), calcium, electrolytes, 25-hydroxyvitamin D (25 (OH) D), and 1,25-dihydroxyvitamin D (1,25 (OH) 2D).

MAIN OUTCOME MEASURES

Mean values of these substances, together with reductions in serum calcium concentration, relative youth, increased alkaline phosphatase activity, large goitre, and increased serum TSH binding inhibitory globulin concentration.

RESULTS

Women had significantly lower calcium concentrations than men (mean (SD) 2.37 (0.13) compared with 2.43 (0.07), p = 0.003). Serum calcium concentrations correlated significantly with concentrations of 25 (OH) D (p < 0.001). 121 of the women (68%) compared with 13 (29%) of men had vitamin D deficiency as defined as 25 (OH) D < 25 nmol/l (p < 0.05). 15 patients (8%) developed tetany postoperatively compared with I man (2%, p = 0.2).

CONCLUSION

Women with Graves disease are more susceptible to calcium and vitamin D deficiency than men, which may account for the higher incidence of postoperative tetany among women with the disease.

Postoperative tetany in Graves disease: important role of vitamin D metabolites

OBJECTIVE

To test the authors' hypothesis of the causal mechanism(s) of postoperative tetany in patients with Graves disease.

SUMMARY BACKGROUND DATA

Previous studies by the authors suggested that postoperative tetany in patients with Graves disease occurs during the period of bone restoration and resulted from continuation of a calcium flux into bone concomitant with transient hypoparathyroidism induced by surgery.

PATIENTS AND METHODS

A prospective study was carried out to investigate sequential changes in serum levels of intact parathyroid hormone (iPTH), calcium and other electrolytes, 25-hydroxyvitamin D (25OHD), 1,25-dihydroxyvitamin D (1,25(OH)2D), and bone metabolic markers in 109 consecutive patients with Graves disease who underwent subtotal thyroidectomy.

RESULTS

Preoperative serum iPTH levels negatively correlated with ionized calcium levels and positively correlated with 1,25(OH)2D or 1,25(OH)2D/25OHD. After the operation, there was a significant decline in levels of ionized calcium, magnesium, and iPTH. Serum iPTH was not detected in 15 patients after surgery. Four of these 15 patients, and 1 patient whose iPTH level was below normal, developed tetany. Preoperative serum ionized calcium levels were significantly lower, and iPTH levels were higher, in the 5 patients with tetany than in the 11 patients who did not develop tetany despite undetectable iPTH levels. The tetany group had significantly lower serum 25OHD levels and higher 1,25(OH)2D levels, and had increased 1,25(OH)2D/25OHD as an index of the renal 25OHD-1-hydroxylase activity than those in the nontetany group. These results suggest that patients with a high serum level of iPTH as a result of low serum calcium levels (secondary hyperparathyroidism) are susceptible to tetany under conditions of hypoparathyroid function after surgery.

CONCLUSIONS

Postoperative tetany occurs in patients with secondary hyperparathyroidism caused by a relative deficiency in calcium and vitamin D because of their increased demand for bone restoration after preoperative medical therapy concomitant with transient hypoparathyroidism after surgery. Calcium and vitamin D supplements may be recommended before and/or after surgery for patients in whom postoperative tetany is expected to develop.

Magnesium deficit in a sample of the Belgian population presenting with chronic fatigue

97 patients (25 per cent males, ages ranging from 14 to 73 years, median 38 years) with complaints of chronic fatigue (chronic fatigue syndrome, fibromyalgia or/and spasmophilia) have been enrolled in a prospective study to evaluate the Mg status and the dietary intake of Mg. An IV loading test (performed following the Ryzen protocol) showed a Mg deficit in 44 patients. After Mg supplementation in 24 patients, the loading test showed a significant decrease (p = 0.0018) in Mg retention. Mean values of serum Mg, red blood cell Mg and magnesuria showed no significant difference between patients with or without Mg deficiency. No association was found between Mg deficiency, CFS or FM. However serum Mg level was significantly lower in the patients with spasmophilia than in the other patients.

[The role of paraclinical studies in the diagnosis of hypomagnesemia spasmophilia]

Assuming that Ca+2 and Mg+2 play an important role in the cell (especially the neuronal and muscular ones) membrane excitability, this paper presents the place that the paraclinical specific investigations have in the proper diagnose of normal calcium serum level hypo-magnesium spasmophilia. A number of 52 patients presenting significant clinical spasmophilia, of age between 21 and 55 years old, from different professions and social classes, were selected for this study. Paraclinical investigations (spectrophotometry) showed a normal serum calcium level (an average of 9.22 mg%); also, a decrease of Mg+2 serum level (an average of 1.41 mg%) and normal levels for Na+ (3.04 g/l) and K+ (0.21 g/l). The electrophysiological investigations (EMG, EEG, VCN m, EKG) performed showed, on the EMG recordings, in 85% of the cases the presence of the typical spasmophilic repetitive discharges, increased when using compression ischemia and 3 minutes hyperventilation, while on the EEG recordings, most patients demonstrated the presence of diffuse or mainly frontal lobe cortical bioelectrical activity alteration, either in spontaneous conditions or after specific stimulation (3 minutes hyperventilation or SLI). The muscle bioelectrical activity was analyzed by mean of EMG recordings--a decrease of VCN m was detected on the SPE nerve (34.4 m/s) and also on the SPI nerve (34.2 m/s) The EKG recordings performed showed in 5% of the cases the presence of the ventricular repolarization disturbances (flat T waves). After receiving a proper treatment which included oral administration of calcium and magnesium gluconolactate, magnesium gluconolactate with B6 vitamin or Trimagant, there were important changes of all the studied parameters and so, as a specific therapy, we recommend the use of Mg+2 compounds, because it demonstrates a significant improvement of the clinical symptoms in spasmophilia and has no danger to precipitate in the body as Ca+2 exceeding does.

Postoperative tetany in patients with Graves' disease: a risk factor analysis

OBJECTIVE

There is little information regarding the clinical risk factors for postoperative tetany in patients with Graves' disease. We analysed the risk factors responsible for postoperative tetany by univariate and multivariate analysis in thyroidectomized patients with Graves' disease, and we discuss the mechanisms of hypocalcaemia and tetany after surgery.

PATIENTS

The subjects were 1742 consecutive patients with Graves' disease who underwent subtotal thyroidectomy between 1992 and 1994.

RESULTS

Univariate analysis of 15 possible risk factors demonstrated that 10 were significant: sex, required operation time, blood loss, preoperative serum calcium level, estimated weight of thyroid remnant, size of goitre, amount of excised thyroid tissue, serum alkaline phosphatase concentration, age at operation and TSH-binding inhibitory immunoglobin (TBII). In multivariate analysis in female patients, the risk factors were: preoperative lower serum calcium level, younger age, higher serum alkaline phosphatase concentration, larger size of goitre and higher value of TBII, in order of decreasing probability of significance.

CONCLUSION

These results, combined with previous observations in which a significant decline in serum parathyroid hormone level was found in patients with Graves' disease who suffered postoperative tetany, suggests that postoperative tetany may occur during the period of bone restoration due to antithyroid drug therapy and be due to continuation of a calcium flux bone concomitant with transient hypoparathyroidism induced by surgery. Calcium supplements during preoperative period and/or after surgery may be appropriate for patients who are anticipated to develop postoperative tetany based on these risk factors.

An incidental finding of Gitelman's syndrome

Gitelman's syndrome is characterised by hypokalaemia, hypomagnesaemia and tetany. This rare disorder is not well described in the literature, probably due to its similarity with Bartter's syndrome. We describe the symptoms and treatment of a young patient whom we consider to have Gitelman's syndrome.

[Hypocalcemic tetany in 'alternative' soy milk nutrition in the first months of life]

A 14 weeks old infant was admitted to the intensive care unit with life-threatening hypocalcemic-hyperphosphatemic spasms. Hypocalcemia-hyperphosphatemia was found to have been caused by feeding a high phosphate/ low calcium soy milk. The daily uptake of calcium was calculated to have been 3.3-6 mmol that of phosphate 30 mmol. The parents strongly believed that soy milk formulas were equivalent to breast milk and cow's milk formulas and lived on a strictly vegetarian diet. Therapy with calcium (at an initial dose of 2.25 mmol/kg/day) and 1.25 OH vitamin D3 (Rocaltrol, 0.25 microgram/day) normalized Ca, PO4, vitamin D and parathyroid hormone levels rapidly. Vegetarian feeding had led to life-threatening hypocalcemic hyperphosphatemic spasms in the infant. We conclude that malnutrition and false nutritional beliefs have to be included as a potential cause of early hypocalcemia in infants.

Hypomagnesaemic tetany

Hypomagnesaemic tetany (hypomagnesaemic tetany with secondary hypocalcaemia) is a rare inherited form of hypomagnesaemia. Initial reports involved affected males only; however, affected females have also been reported. The case of a child with hypomagnesaemic tetany is described, the biochemical and genetic aspects of this condition are reviewed and the importance of the assessment of renal magnesium excretion in patients presenting with hypomagnesaemia is highlighted.

[Katacalcin levels in healthy children and children with spasmophilia]

The calcitonin (CT) gene encodes at least 3 peptides: CT, the 21-aminoacid carboxyl-terminal flanking peptide (katalcin or PDN-21) and CT-gene related peptide. Normal thyroid C-cells as well as malignant ones co-secrete CT and PDN-21 in response to hypercalcemia, so assay of PDN-21 may be an usefull method to assess C-cells secretion. Because of our knowledge no data are available on PDN-21 values in children, we measured this peptide in healthy children and in spasmophilia (Sp), a disease that has been related to CT deficiency. We studied 16 healthy children (9 males, 7 females; aging from 3.0 to 11.6 years) and in 21 patients with diagnosed Sp (8 males, 13 females, aging from 4.6 to 13.0 years). PDN-21 were assayed in whole serum by RIA using synthetic human PDN-21 for standards, 125I-PDN-21 for tracer and specific antiserum. CT was measured the serum of the same subjects by RIA using an ultrasensitive methods. In healthy children PDN-21 serum values were 12.3 +/- 2.0 pg/ml and no significant differences were found between males and females. Children with Sp showed slow higher PDN-21 concentrations (14.0 +/- 1.4 pg/ml) than normals, but the difference was not statistically significant. Also CT values were not significantly different between normal children (21.4 +/- 3.7 pg/ml) and patients with spasmophilia (22.5 +/- 1.8 pg/ml). A high significant positive relation was found between katalcacin and CT levels in normals as well as in spasmophilics. The physiological effects of PDN-21 are actually unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

[The mechanism of postoperative tetany in Graves' disease]

The levels of serum calcium (Ca), inorganic phosphate (P) and mid-molecular parathyroid hormone (PTH) were measured in 37 patients with Graves' disease (12 in hyperthyroid state, 25 in euthyroid state followed by subtotal thyroidectomy), 6 with papillary carcinoma of the thyroid, 8 with benign nodular goiter and 19 healthy control subjects in order to investigate the change in these levels before and after thyroidectomy. The levels of serum Ca and P of the hyperthyroid patients with Graves' disease were 9.73 +/- 0.30 mg/dl and 4.47 +/- 0.44 mg/dl, respectively, which were significantly higher than those of healthy control subjects. No significant difference in the levels of serum PTH was observed between hyperthyroid patients with Graves' disease and healthy control subjects. The levels of serum Ca, P and PTH of euthyroid patients with Graves' disease were not significantly different from those of healthy control subjects. In the patients with Graves' disease who had undergone subtotal thyroidectomy followed by postoperative tetany, serum Ca and serum PTH decreased significantly from 9.39 +/- 0.45 mg/dl to 7.90 +/- 0.33 mg/dl and from 406.6 +/- 164.4 pg/ml to 229.9 +/- 136.0 pg/ml, respectively, after surgery, but there was no change in serum P. In the patients without postoperative tetany, serum Ca and serum P decreased significantly after surgery from 9.65 +/- 0.36 mg/dl to 9.15 +/- 0.33 mg/dl and from 4.03 +/- 0.46 mg/dl to 3.47 +/- 0.54 mg/dl, respectively, without any change in the levels of serum PTH. In the patients with papillary carcinoma or benign nodular goiter without postoperative tetany, the levels of serum Ca, P and PTH did not change after surgery. In the patients with papillary carcinoma followed by postoperative tetany, serum Ca decreased significantly after surgery with concomitant decrease of serum PTH. It was concluded that excessive thyroid hormones influenced Ca metabolism, and the transient tetany following subtotal thyroidectomy for Graves' disease seemed to be due to both the absorption of Ca by hungry bone and parathyroid hypofunction.

[Tetany secondary to hypokalemia]

The authors describe a case of tetany not related to the common causes of this clinical symptom, such as hypocalcemia, hypomagnesemia, and alkalosis. Severe hypokalemia secondary to the use of diuretics was detected; its correction reverted the symptoms.

Computerized electroencephalographic mapping in hypomagnesian spasmophilic syndromes

Out of 397 patients presenting hypomagnesaemia there were selected for this study only 107 cases with neurotic and neuromuscular clinical picture (sometimes with short and simple loss of consciousness) without any sign of organic cerebral lesion. The dosing of the seric and erythrocytic magnesium was performed by means of a colorimetric method of Mann and Yoe, modified by the authors. In all the cases, the EEG and EMG changes were studied by simultaneous recording of the EEG and EMG before, during and after hyperpnoea. In these 107 selected cases (divided into three groups: children, adolescents and adults) the computerized electroencephalographic maps (CEM) were carried out by an original method, transcribing the primary data of Hjorth's NSD parameters (Amplitudes and Frequencies) into a Romanian M-118 microcomputer, by a technique with analog-digital conversion. The CEM (in white-black and in colour cartography) were performed for various epochs, including the sequential ones (second by second, all along the EEG discharges during and after hyperpnoea). By these methods, we analyzed the dynamic fluctuation and temporo-spatial cortical distribution of the sinusoidal slow waves generated by the reticulate neuronal hypersynchrony. The CEM showed some differences in the three groups of hypomagnesemic syndromes selected.

[Chronic normocalcemic constitutional tetany: clinic and etiopathogenic aspects. Description of a case]

Tetany is a state of hyperexcitability of the central and peripheral nervous system due to abnormal concentrations of serum electrolytes. However tetanic individuals without any detectable abnormalities, are also encountered. This last condition has been named "chronic normocalcemic tetany or spasmophilia". The case here reported, allows the authors to review the literature concerning normocalcemic tetany and let them focus on two similar and sometimes overlapping entities, spasmophilia and hyperventilation syndrome, both common causes of recurrent, atypical symptoms and tetany.

Electrical activity induced by ischemia in the skeletal muscle of patients with spasmophilia

The incidence of spontaneous electrical activity during ischemia was studied in normal and spasmophilic subjects with a Bronk electrode inserted in the first dorsal interosseous muscle. Subjects were of both sexes, aged 16 to 65 years. The diagnosis of spasmophilia was established electromyographically by a variant of the Alajouanine test. Ischemia induced in many cases an electrical activity consisting of discharge potentials that have the amplitude, duration and morphology of motor unit potentials. The number of discharging motor units varied, sometimes leading to an electrical Trousseau associated to a carpal spasm. The discharge of individual motor units was irregular and practically uninfluenced by passive manipulations on the muscle or voluntary contraction. The activity started usually 30 sec to 1 min after the onset of ischemia, reached a maximal intensity (as to the number of motor units and frequency of discharge) in about 1 min and declined gradually in the following minutes. This activity was encountered in 55.06% of 770 cases of spasmophilia and only in 11.66% of 283 normal subjects, with a tendency to more intense discharge in spasmophilia. Its incidence in the spasmophilic group was closely related to the intensity of spontaneous repetitive discharges appearing electromyographically after the activation test, reaching 78.63% in most severe cases. The behaviour was interpreted as indicating a higher susceptibility in spasmophilia of axons to depolarization induced by hypoxia. This higher susceptibility appears as an important component of the excitability alterations leading to the complex neuromuscular disorders occurring in spasmophilia.

[A case of spasmophilic syndrome]

The case is described of a 43 year old woman with spasmophilic syndrome. For 12 years she had suffered from fainting fits, marked morning asthenia, anxiety, depression, widespread arthromyalgia, blood pressure fluctuations, precordial pains, paresthesia and painful nocturnal cramp. This clinical picture appeared in a subject with a double left kidney and stones in the supernumerary ureter, enlargement of the pancreatic head and tail revealed by a CAT scan and an earlier cholecystectomy. Given the multiplicity of symptoms diagnosis was necessarily by a process of elimination. The data providing grounds for optimism were a positive Chvostek's sign, stable calcium phosphorus profiles, a reduction in ionised calcium and favourable eletromyographic readings.

Pathophysiology of pH and Ca2+ in bloodstream and brain

The highlights of the literature and our work on tetany and hyperventilation are reviewed. Our studies concern the following: (1) the changes of [Ca2+] in circulating plasma caused by respiratory and "metabolic" acidosis and alkalosis; (2) critical plasma [Ca2+] levels associated with signs of tetany and neuromuscular blockade; (3) changes in cerebral [Ca2+]o caused by hypo- and hyper-calcaemia, and the changes in cerebral [Ca2+]o and pHo caused by acute systemic acidosis and alkalosis; and (4) effects of changing [Ca2+]o and pHo levels on synaptic transmission in hippocampal formation. Our main conclusions are (1) changes of plasma [Ca2+] caused by "metabolic" pH changes are greater than those associated with varying CO2 concentration; (2) acute systemic [Ca2+] changes are associated with small cerebral [Ca2+]o changes; (3) the decreases in systemic and cerebral [Ca2+]o caused by hyperventilation are too small to account for the signs and symptoms of hypocapnic tetany; (4) moderate decrease of [Ca2+]o depresses and its increase enhances synaptic transmission in hippocampal formation; and (5) H+ ions in extracellular fluid have a weak depressant effect on neuronal excitability. CO2 is a strong depressant, which is only partly explained by the acidity of its solution. CO2 concentration is a significant factor in controlling cerebral function.

Calcium deficiency and supraorbital headache: a clinical study of adult subjects

The present study was aimed at investigating the relationship between "chronic constitutional tetany" (spasmophilia) and headache. Several adult patients presenting with neuromuscular hyperexcitability, anxiety, dysautonomia, and oculofrontal headache were subjected to a series of ion and hormone blood tests, and the results were compared with those in control subjects. Calcium and parathyroid hormone levels were significantly decreased, and phosphorus and beta-endorphin-like immunoreactivity were significantly increased. A subgroup of the patients had all four abnormalities. In most cases the family history was positive for headache. Sleep disturbances and personal histories of periodic syndrome in infancy were recorded. It is concluded that a correlation may exist between the symptoms assessed and an impairment of some ion and hormone levels. There are several traits in common with "common migraine", and our patients may form a subgroup of that group. A possible linkage between headache/tetany and the periodic and hyperventilation syndromes is discussed. The increased beta-endorphin-like immunoreactivity is putatively a reactive phenomenon.

Increased calcium tolerance in patients with tetania latenta

We studied the calcium tolerance on 59 subjects with tetania latenta. The calcium tolerance was tested by induced hypercalcemia (Klotz's test). In 12 cases the dynamic changes of serum magnesium were also investigated during the same test. Eight cases exhibited a normal tolerance and 51 exhibit an abnormal response, calcemia remaining at a high value after 4 hours of the test. The magnesium values remained low when finishing the test (p less than 0.001). It was concluded that 86 per cent of the subjects having tetania latenta and exhibiting an increase of calcium tolerance had a possible calcitonin deficiency. The significance of the magnesium decrease remains unclear. These phenomena have not been observed in Graves' disease and in the Turner's syndrome.

Magnesium concentrations in the ventricular and lumbar cerebrospinal fluid of hypomagnesaemic cows

Samples of ventricular and lumbar cerebrospinal fluid (CSF) were taken at intervals from six lactating dairy cows, made hypomagnesaemic by feeding a magnesium-deficient diet. Initially the ventricular CSF had a higher magnesium concentration than lumbar CSF but as the cows became hypomagnesaemic the magnesium concentration in ventricular CSF decreased more rapidly than that in lumbar CSF. Tetany occurred when the concentration of magnesium in ventricular CSF fell below about 0.5 mmol litre-1. Intravenous infusion of magnesium into two hypomagnesaemic cows increased the concentration of magnesium in ventricular CSF before there was any change in the lumbar CSF. Newly formed CSF from the ventricles appeared to be more sensitive to changes in the concentration of magnesium in plasma than lumbar CSF which equilibrates with the diffusible magnesium of the central nervous system.

Changes in blood composition of pregnant cows during the onset of hypomagnesaemia

Magnesium, calcium, phosphate, total protein and free fatty acid concentrations, and a lipase activity using p-nitrophenylpalmitate NP-C16) as a substrate, were determined in the serum of 15 pregnant Aberdeen Angus cows grazing a Phalaris tuberosa pasture with a tendency to induce tetany. A gradual decrease in magnesium concentrations, but no definite change in the other parameters, was observed when the results were plotted directly against the time of the experiment. When the results were plotted as a function of the stage of pregnancy or lactation of the animals, magnesium concentrations showed a more steady decrease which was associated with increases in calcium concentrations and, at the lowest magnesium concentrations, with increases in phosphate concentrations. Total proteins and free fatty acids remained fairly constant and the highest lipase activity was associated with parturition. The lowest magnesium concentrations in serum did not correspond with high levels of either lipase or free fatty acids. The hypomagnesaemia observed in this experiment was attributed to the high potassium:calcium and magnesium ratio in the pasture and to the physiological condition (pregnant and lactating) of the animals. None of the parameters evaluated in this paper would be more sensitive than serum magnesium levels for the early detection of the conditions that predispose grazing cattle to grass tetany.

[Current status of normocalcemic tetany]

The author describes the actual state of research of normocalcemic tetany. Since 1959 the infusion test with ethylene diamine tetraacetic acid (EDTA) has won a central position. The EDTA test gives the possibility to classify tetanic symptoms into the circle either of hypocalcaemic or normocalcaemic syndrome. In the latter case the functional disturbance is to be treated in a form of combined therapy by tranquilizers and psychosomatic measures.

Life span and tissue distribution of 111indium-labeled blood platelets in hypomagnesemic lambs

Circulating platelets may be activated by exposed triple-helical collagen in atherosclerotic lesions in Mg-deficient ruminants. Autologous platelets, labeled in vitro with 111In and determined to be active, were injected into 5 hypomagnesemic and 3 control lambs fed semipurified diets with 100 or 2,000 mg of Mg/kg of feed for 3 months. During the first 68 hours, 111In concentrations were 11 times higher in packed cells than in plasma. Packed-cell 111In increased 60% during the first 2 hours, probably due to initial tissue sequestration and later release of labeled platelets. Thereafter, platelet half-life span averaged 60 and 63 hours for hypomagnesemic and control lambs. After 68 hours, lambs were injected with native vascular collagen fibrils at 500 micrograms/kg of body weight to initiate reversible platelet aggregation. Within 1 minute, 83% of packed-cell 111In disappeared from circulation. Thirty minutes later, the lambs were euthanatized and necropsied and in the lungs, liver, and spleen, 111In averaged 24%, 19%, and 9%, respectively, of 111In injected 68 hours earlier. Organ deposits were not affected by Mg intake, but 111In in the lungs was somewhat lower in 2 lambs injected with inactivated collagen. Pathologic changes induced by reversible platelet aggregation were compatible with right ventricular failure complicated by pulmonary edema, similar to changes in hypomagnesemic lambs that died spontaneously. Platelets in blood exposed to vascular lesions in hypomagnesemic ruminants could be a major mortality risk factor in grass tetany disease.