Lactation tetany

Essentiality for animals, lactation tetany, grass tetany, vasodilation, hyperirritability in rats... 

Figure 2. Force generation and energy metabolism in human quadriceps femoris muscle stimulated intermittently at 20 Hz, with 1.6 sec tetani with 1.6 sec rest periods between tetani. The upper panel shows force, ATP turnover rate, and pH the middle panel, the concentrations of PCr, P and lactate and the lower panel, ATP, ADP, IMP, H, and calculated H2PO4. From Hultman et al. (1990), with permission from Human Kinetics Publishers.

A 22-year-old woman took an overdose of propafenone (amount unknown) and developed tetany and then generalized convulsions requiring intravenous clonazepam (44). She had a low blood pressure and first-degree atrioventricular block associated with prolonged intraventricular conduction. She was intubated and given intravenous fluids, equimolar sodium lactate, dopamine, and adrenaline. Her cardiac conduction returned to normal. 

Two other elements of unusual interest and importance in animal nutrition are Mg and Se. The most urgent problem associated with Mg is grass tetany, particularly in lactating cows. This disease is caused by a conditional Mg deficiency in animals, due to a low intake of this element or inef-... 

Three forms of calcium are in equilibrium in serum nondiffusible calcium bound primarily to albumin diffusible complexes of calcium with lactate, bicarbonate, phosphate, sulfate, citrate, and other anions and diffusible ionized calcium (Ca " ). Ionized calcium accounts for approximately half of total serum calcium, and nondiffusible and complexed calcium account for 45% and 5%, respectively. Ionized calcium is the physiological active form its concentration is regulated by the parathyroid gland. A decrease in serum ionized calcium can cause tetany (involuntary muscle contraction) and related neurological symptoms, regardless of the total serum calcium concentration. 

Osteomalacia is most often seen during pregnancy and lactation and is characterized by osteoporosis, deformity and fracture of bones, and tetany. The concentration of calcium in serum is low, often less than 7 mg. per 100 ml., and the level of alkaline phosphatase is elevated above the usual adult value of 3 to 5 units. 

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