Prevalence and clinical implications of hypocalcemia in acutely ill patients in a medical intensive care setting: Dasai TK Carlson RW, Geheb MA. Am J Med 1988; 84:209–214

Abstract

s 5.59 either gentamicin or tobramycin (2 mg/kg/LBW) was given over 30 minutes with subsequent maintenance dose and dosing intervals calculated using the nomogram of Hull and Sarubbi. Serum aminoglycoside levels were drawn 30 minutes after the end of the loading dose and 30 minutes after the third maintenance dose. Ten of the 14 cases had a peak concentrations of <6 fig/ml, an inadequate level for good survival rates. There was good correlation between the 30minute-after-loading-dose level and the 30-minute-afterthird-maintenace-dose level. The authors conclude that current dosage recommendations for aminoglycosides may be too low for effective reduction of mortality, and that peak gentamicin levels 30 minutes after the loading dose correlated well with the traditional after-third-maintenance-dose level, and thus could be used to adjust subsequent dosing. [Alan F. Chou, MD] 0 REYE’S SYNDROME IN ADULTS. Ede RJ, Williams R. BrMed J 1988; 296:517-518. This article briefly reviews Reye’s syndrome in adults. The majority of adult cases have occurred in young adults, but at least seven cases have been over 35 years of age and the oldest was 61. The presentation is similar to that in children; a few days following influenza, gastroenteritis, or an upper respiratory infection, the patient begins vomiting, which is followed shortly by encephalopathy. Those who are severely ill show signs of raised intracranial pressure including abnormal pupillary responses, increased muscle tone, and posturing. Laboratory abnormalities reflect hepatocellular damage with a fourfold increase in serum transaminase activity and a prolonged prothrombin time. Serum bilirubin is elevated but rarely exceeds twice the normal level; clinical jaundice is uncommon. The most constant finding is an increase in blood ammonia level. Hypoglycemia is uncommon. Mortality is similar to that in children, about 30%. The association with salicylate use in adult Reye’s syndrome is less strong than in children. Differential diagnosis of Reye’s syndrome includes viral hepatitis, paracetamol or valproate toxicity, halothane anaesthesia, and urea cycle diseases. Management is directed toward lowering the intracranial pressure. The patient is admitted to the intensive care unit with the head raised 40”. Hyperventilation and mannitol infusion are usually effective. In resistant cases barbiturates may help by decreasing cerebral metabolism. Continuous intracranial pressure monitoring is valuable. The syndrome should be suspected in any adult presenting an encephalopathy of unknown etiology, especially if there is a preceding history of viral syndrome or vomiting. [Paul Howes, MD] 0 MYOCARDIAL INFARCTION: THE FIRST 24 HOURS. Lipkin DP, Reid CJ. Br Med J 1988; 296:947948. This article summarizes the authors’ guidelines for pharmacologic management of myocardial infarctions. Thrombolytic agents have been shown to reduce morbidity and mortality. Recanalization has been shown to be present in 55 % to 75% of patients with the use of streptokinase; tissue plasminogen activator may be more effective and cause fewer complications, but costs about eight times as much. All patients who present within 4 hours of onset of pain and without contraindications should receive a thrombolytic agent. Since vasospasm may aggravate an underlying thrombotic process, the authors recommend the use of intravenous nitrates in all patients. Intravenous metoprolol or atenolol reduces short term mortality by about 15% and should be used in the absence of contraindications (bradycardia, conduction defects, overt heart failure, or cardiogenic shock). Calcium channel blockers have no effect on morbidity or mortality in long term follow-up studies. Prophylactic lidocaine is not justified, as ventricular fibrillation is rare and usually responds to immediate cardioversion, which is usually available in the coronary care unit. [Paul Howes, MD] Editor’s Note: British practice differs in many ways from standard American practice; which is better is an unresolved question. 0 MANAGEMENT OF UROLITHIASIS DURING PREGNANCY. Rodriguez PN, Klein AS. Surg Gynecol Obstet 1988; 166:103-106. The authors discuss the treatment of ureterolithiasis during pregnancy, using six case reports to help illustrate their approach. The incidence of renal calculi is the same in pregnant and nonpregnant individuals with 70% to 80% of all symptomatic calculi passing uneventfully using conservative management. They state that radiation exposure with a standard IVP is acceptably low and that medical benefits outweigh the risk to fetus and mother. However, all of their IVPs were described as “limited,” and none were performed in the first trimester. The use of renal ultrasound to diagnose calculi in pregnancy is complicated by difficulty in differentiating upper tract dilation secondary to calculi from the physiologic hydronephrosis of pregnancy. In the 20% to 30% of patients requiring intervention, the authors recommend endoscopic extraction; if this fails they recommend manipulation of the stone up to the kidney, or bypassing it using a ureteral stent to delay definitive intervention until the postpartum period. They further suggest that it is reasonable to prophylactically remove asymptomatic stones prior to conception to prevent possible complications to the pregnancy. [Cheryl Melick, MD] Cl COMPARISON OF TWO DOSE REGIMENS OF INTRAVENOUS TISSUE PLASMINOGEN ACTIVATOR FOR ACUTE MYOCARDIAL INFARCTION. To101 EJ, George BS, Kereiakes DJ, Candela RJ, Abbottsmith CW, et al. Am JCardioll988; 61:723-738. Three hundred eighty-six patients with acute myocardial infarction who were given 150 mg of TPA were divided into two groups to determine which dosing regimen yielded the highest reperfusion rate with the lowest complication rate.