Hypocalcemic tetany

The answer is c. (Hardman, p 15230 Administration of intravenous CaG would immediately correct the tetany that might occur in a patient in whom a thyroidectomy was recently performed. Parathyroid hormone would act more slowly but could be given for its future stabilizing effect. Long-term control of a patient after a thyroidectomy can be obtained with vitamin D and dietary therapy Calcitonin is a hypocalcemic antagonist of parathyroid hormone. Plicamycin (mithramycin) is used to treat Paget s disease and hypercalcemia. The dose employed is about one-tenth the amount used for plicamycin s cytotoxic action. 

Rapid intravenous administration of this drug causes hypocalcemic tetany... 

Zipser RD, Bischel MD, Abrams DE. Hypocalcemic tetany due to sodium phosphate ingestion in acute renal failure. Nephron 1975 14 378-381. 

In patients with edema or ascites associated with low plasma albumin, the effect of albumin infusion is very transient because of rapid equilibration with the extravascular fluid. The only situation in which infusion is usually beneficial is in acute hypovolemic shock in this case, rapid infusion may result in hypocalcemic tetany, because albumin binds Ca " with relatively high affinity. 

EDTA, its sodium salt (edetate disodium, Na2EDTA), and a number of closely related compounds chelate many divalent and trivalent metals. The cation used to make a water-soluble salt of EDTA has an important role in the toxicity of the chelator. Na2EDTA causes hypocalcemic tetany. However, edetate calcium disodium (CaNa2EDTA) can be used for treatment of poisoning by metals that have higher affinity for the chelating agent than does Ca. ... 

Hypocalcemic tetany is treated with the intravenous administration of calcinm gluconate or calcinm chloride (5 to 10 mL of 10% solution). The effects of these agents are rapid but transient. Furthermore, a 10-mL solution of calcinm chloride and calcinm gluconate contains 270 mg and 70 mg of calcinm, respectively. Because calcinm chloride is a highly irritating substance, it should not be administered... 

Caution Ingestion of coned solns may cause severe G.l. irritation, hematemesis, CNS and cardiac depression, desth. Dilute solns produce little G.l. distress but may cause weakness, muscular twitchings, rarely convulsions, coma, death. Chronic ingestion of small amounts may cause hypocalcemic tetany, urinary calculi, cf. Clinical Toxicology of Commercial Products, R. E. Gosselin et of., Eds. (Williams Wilkins, Baltimore, 4th ed.. 1976) Section III, pp 260-263. 

Magnesium- and phosphate-containing preparations are tolerated reasonably well by most patients. However, they must be used with caution or avoided in patients with renal insufficiency, cardiac disease, or preexisting electrolyte abnormalities, and in patients on diuretic therapy. Patients taking >45 mL of oral sodium phosphate as a prescribed bowel preparation may experience electrolyte shifts that pose a risk for the development of symptomatic dehydration, renal failure, metabolic acidosis, hypocalcemic tetany, and even death in medically vulnerable populations. 

Rapid intravenous administration ofNa. DTA causes hypocalcemic tetany. However, a slow infusion (<15 mg/min) administered to a normal individual elicits no symptoms of hypocalcemia because of the ready availability of extracirculatory stores ofCa L In contrast, CaNa2EDTA can be administered intravenously in relatively large quantities with no untoward effects because the change in the concentration ofCa in the plasma and total body is negligible. 

Hypocalcemia can be caused by PTH deficiency, vitamin D deficiency, various pharmacological agents, and miscellaneous disorders (Table 35.5) (18). A state of hypocalcemia will inhibit calcitonin release. This results in an elevation of PTH biosynthesis and release and indirectly causes an increase in the production of vitamin D. The left wing of Arnaud s butterfly model (Fig. 35.1) would be activated to increase serum calcium concentrations. In the absence of calcitonin, osteoclast activity is unregulated therefore, bone resorption is accelerated. In acute cases of hypocalcemia, specifically in the case of hypocalcemic tetany, PTH is administered to correct the hormonal imbalance. 

Hypocalcemic tetany of infants—Where infants are raised on cow s milk, the Ca P ratio in cow s milk may contribute to the occurrence of hypocalcemic tetany during the first week of life. This postulation is based on the fact that the Ca P ratio in cow s milk is approximately 1.2 1, compared with 2 1 in human milk. Because of this situation, the current recommendation is that in infancy the Ca P ratio in the diet be 1.3 1, decreasing to 1 1 at 1 year of age. 

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