By E. Hamid. Metropolitan State University. 2017.
The function of calcitonin is to lower serum calcium renal tubules and less urinary excretion safe 250 mg chloroquine. The opposite effects in the presence of hypercalcemia, which it does by decreasing occur with phosphate (ie, PTH decreases serum phosphate movement of calcium from bone to serum and increasing uri- and increases urinary phosphate excretion). Thus, it has little effect on long-term calcium production of PTH (hypoparathyroidism) or excessive pro- metabolism. Hypoparathyroidism is most often caused by removal of or damage to the parathyroid glands during neck surgery. Hyperparathyroidism is most Vitamin D (Calciferol) often caused by a tumor or hyperplasia of a parathyroid gland. It also may result from ectopic secretion of PTH by malignant Vitamin D is a fat-soluble vitamin that includes both ergo- tumors (eg, carcinomas of the lung, pancreas, kidney, ovary, calciferol (obtained from foods) and cholecalciferol (formed prostate gland, or bladder). It functions as a hormone ment of hypoparathyroidism are the same as those of hypocal- and plays an important role in calcium and bone metabo- cemia; clinical manifestations of hyperparathyroidism are lism. The main action of vitamin D is to raise serum cal- those of hypercalcemia. It also promotes bone formation by providing adequate serum concentrations of Calcitonin minerals. It must be converted to an intermediate metabolite in Calcitonin is a hormone from the thyroid gland whose secre- the liver, then to an active metabolite (1,25-dihydroxyvita- tion is controlled by the concentration of ionized calcium in the min D or calcitriol) in the kidneys. PTH and adequate he- 368 SECTION 4 DRUGS AFFECTING THE ENDOCRINE SYSTEM patic and renal function are required to produce the active used to treat hypocalcemia and to prevent and treat osteo- metabolite. These agents are described in the following sec- Deﬁciency of vitamin D causes inadequate absorption of tions; names and dosages of individual drug preparations calcium and phosphorus. This, in turn, leads to low levels of are listed in Drugs at a Glance: Calcium and Vitamin D serum calcium and stimulation of PTH secretion. Drugs used for hypercalcemia include bis- this sequence of events produces inadequate mineralization phosphonates, calcitonin, corticosteroids, 0.
Desmopressin and lypressin may be weight (actual and compared with growth charts) and di- inhaled intranasally; vasopressin must be injected cheap chloroquine 250 mg amex. Oxytocin (Pitocin) is a synthetic drug that exerts the same • For clients with diabetes insipidus, assess baseline blood physiologic effects as the posterior pituitary hormone. Thus, pressure, weight, ratio of ﬂuid intake to urine output, it promotes uterine contractility and is used clinically to in- urine speciﬁc gravity, and laboratory reports of serum duce labor and in the postpartum period to control bleeding. Oxytocin must be used only when clearly indicated and when • For clients with diarrhea, assess number and consistency the recipient can be supervised by well-trained personnel, as of stools per day as well as hydration status. CHAPTER 23 HYPOTHALAMIC AND PITUITARY HORMONES 331 itary gland (hypopituitarism). Conditions resulting from Nursing Diagnoses excessive amounts of pituitary hormones (hyperpitu- • Deﬁcient Knowledge: Drug administration and effects itarism) are more often treated with surgery or irradiation. Diagnosis of suspected pituitary disorders should be • Anxiety related to multiple injections thorough to promote more effective treatment, including • Risk for Injury: Adverse drug effects drug therapy. Even though manufacturers recommend corticotropin for treatment of disorders that respond to glucocorti- The client will: coids, corticotropin is less predictable and less con- • Experience relief of symptoms without serious adverse venient than glucocorticoids and has no apparent effects advantages over them. Dosage of any pituitary hormone must be individual- • Comply with procedures for monitoring and follow-up ized because responsiveness of affected tissues varies. Because the hormones are proteins, they must be given by injection or nasal inhalation. If taken orally, • For children receiving growth hormone, assist the family they would be destroyed by proteolytic enzymes in the to set reasonable goals for increased height and weight GI tract. An increasing concern is inappropriate use of growth follow-up procedures (periodic x-rays to determine bone hormone.
Duration of the stimulus Measurement The diameter of Ia afferents is slightly larger than (i) Reﬂex latency is measured to the ﬁrst deﬂection thatof motoraxonsandtheirrheobasicthresholdis of the H wave from baseline purchase chloroquine 250mg mastercard, not to the ﬁrst positive lower,suchthatitisgenerallypossible,particularlyin peak of the commonly triphasic waveform (see the soleus, to evoke an H reﬂex with stimuli below motor vertical dashed line in Fig. The strength–duration curves (ii)Inpracticeitmakeslittledifferencewhetherthe for motor axons and Ia afferents differ and, as a amplitudeorthesurfaceareaofthereﬂexisassessed result, the optimal stimulus duration for eliciting the or whether amplitude is measured for the negative Hreﬂex is long (1 ms; see Paillard, 1955;Panizza, phase only or from negative peak to the following Nilsson & Hallett, 1989). Unipolar and bipolar stimulation The best method for ensuring that Ia afferents are Cross-talk excitedatlowerthresholdthanmotoraxonsinvolves PickupoftheEMGpotentialsfromanadjacentmus- placing the cathode over the nerve and the anode cle can occur if there is spread of the test stimulus – on the opposite side of the limb, so that current electrical to another nerve (H reﬂex), or mechanical passes transversely through the nerve. The soleus to another muscle (tendon jerk) (see Hutton, Roy & and quadriceps H reﬂexes are commonly evoked by Edgerton, 1988). Even if this does not occur, it can monopolar stimulation of the posterior tibial nerve The monosynaptic reﬂex 7 (cathode in the popliteal fossa, anode on the anter- for the M wave. This difference is probably due to ior aspect of the knee) and the femoral nerve (cath- the extreme brevity (∼0. However, in duration that favours motor axons with respect to Ia areas where there are many nerves, bipolar stimula- afferents (Panizza et al. The same applies to the stimulation of H and M recruitment curve the deep peroneal branch of the common peroneal The recruitment curve nerve (tibialis anterior) at the ﬁbular neck and of the sciatic nerve (hamstrings) at the posterior aspect As the intensity of the electrical stimulus to the pos- of the thigh. It is generally stated that the cathode terior tibial nerve is increased, there is initially a pro- shouldthenbeplacedoverthenervewithanodedis- gressive increase in amplitude of the soleus reﬂex tal(orlateral)toavoidthepossibilityofanodalblock. Furtherincreasesintheintensityoftheteststim- Frequency of stimulation ulus cause the M wave to increase and the H reﬂex Because of post-activation depression (see to decrease ((c) and (g)). Finally, when the direct Chapter 2), there is reﬂex attenuation as stim- motor response is maximal, the reﬂex response is ulus rate is increased above 0. This is because requires at least 10 s to subside completely, but the antidromic motor volley set up in motor axons its effects are sufﬁciently small after 3–4 s to allow collides with and eliminates the H reﬂex response testingat0. Note that, when it ﬁrst tutes a compromise between reﬂex depression and appears in the EMG, the M response involves axons the necessity to collect a large number of responses ofthelargestmotoneurones(e.
For example purchase 250mg chloroquine otc, Immunization or vaccination involves administration of an hepatitis B, inﬂuenza, and pneumococcal vaccines are antigen to induce antibody formation (for active immunity) recommended for selected groups of people. Immunization of adults and children at high risk of ex- rations used for immunization are biologic products prepared posure to a particular disease. For example, some dis- by pharmaceutical companies and regulated by the Food and eases (eg, yellow fever) rarely occur in most parts of Drug Administration (FDA). Thus, immunization is recommended only for people who live in or travel to geographic areas where the disease can be contracted. AGENTS FOR ACTIVE IMMUNITY The biologic products used for active immunity are vaccines Contraindications to Use and toxoids. Vaccines are suspensions of microorganisms or their antigenic products that have been killed or attenuated Vaccines and toxoids are usually contraindicated during febrile (weakened or reduced in virulence) so that they can induce illnesses; immunosuppressive drug therapy (see Chap. Attenuated live vaccines produce immunity, usually lifelong, that is similar to that produced by natural infection. However, there is a small risk of producing disease with live AGENTS FOR PASSIVE IMMUNITY vaccines, especially in people with impaired immune function. Vaccines developed with recombinant deoxyribonucleic acid Immune serums are the biologic products used for passive im- (DNA) technology have a low risk for causing active disease. They are used to provide temporary immunity in peo- Toxoids are bacterial toxins or products that have been ple exposed to or experiencing a particular disease. The goal of modiﬁed to destroy toxicity while retaining antigenic prop- therapy is to prevent or modify the disease process (ie, decrease erties (ie, ability to induce antibody formation). They may consist of whole clude aluminum phosphate, aluminum hydroxide, or calcium serum or the immunoglobulin portion of serum in which the phosphate.