Maimonides and his scene.
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History, Medieval↗
Biomedical subjects
S Papper
Publications and source records attributed to S Papper.
Impaired renal tubular reabsorption of sodium in hypothyroid man.
The renal response to acute salt loading and to stimuli for rapid sodium conservation was studied in 14 patients with untreated myxedema and in 13 euthyroid control subjects in balance on a 155 mEq. sodium intake. The salt-loading studies reveal urinary excretion of sodium in the myxedema patients within the range of controls despite reductions of 34 per cent in glomerular filtration (p less than 0.001) and 37 per cent in filtered load of sodium (p less than 0.001) in the former group. The capacity to conserve sodium in response to stimuli for rapid sodium conservation [postural change and administration of a supramaximal dose of 9alpha-fluorohydrocortisone (9alpha-F)] was impaired in patients with myxedema. The per cent decrease in sodium excretion during the upright posture in the hypothyroid patients was 28 per cent, less than half that observed in the control subjects, 62 per cent (p less than 0.005). Following administration of 2 mg. of 9 alpha-F the per cent decrease in sodium excretion was less (p less than 0.05) in the hypothyroid patients (50 per cent) than in control subjects (72 per cent). In all studies, baseline sodium excretion was comparable in both groups. Fractional excretion of sodium was significantly increased in the hypothyroid patients prior to (p less than 0.005) and during saline loading (p less than 0.05) and at the time of the subnormal responses to stimuli for acute sodium conservation (p less than 0.05 less than 0.005). Potassium excretion was reduced in the hypothyroid patients, even after 9alpha-F. These observations indicate decreased tubular reabsorption of sodium in myxedema under the experimental conditions described. The findings are most consistent with a role for thyroid hormone in normal sodium reabsorption. That this is not related to mineralocorticoid deficiency is suggested by the impaired sodium reabsorptive response to 9alpha-F.
Adult↗
Sodium and water: an overview.
The renal regulation of sodium is intertwined with the extracellular fluid volume (ECFV). Most adjustments in sodium elimination in man are accomplished via alterations in tubular reabsorption. The latter is sensitive to change in ECFV. An expanded ECFV results in less reabsorption and more excretion of sodium, and a contracted ECFV has the converse effect. There are direct and indirect mechanisms whereby ECFV influences sodium reabsorption. Patients with nephrotic syndrome, heart failure, and cirrhosis "behave" physiologically as normal individuals with a contracted ECFV. Water balance is normally determined by intake and losses in sweat which is always hypoosmotic to plasma, by evaporation from skin and lungs, and through renal excretion. The major factors that determine the ability to concentrate the urine are (1) the establishment of a concentrated environment around the collecting ducts, and (2) the elaboration and effects on the kidney of antidiuretic hormone. The evaluation of a patient with abnormalities of sodium and water rests initially and largely on clinical information. The clinical setting provides clues to anticipating, preventing, and interpreting distortions of body sodium and water. The laboratory can detect an abnormality, confirm or refute clinical assessment, and assist in the quantitative aspects of treatment and its efficacy.
Aldosterone↗
Fluid and electrolyte disturbances in cirrhosis.
Glomerular filtration rate and renal plasma flow may be normal, reduced or increased in cirrhosis. The mechanism of departures from normal is not known. Other renal functional changes in cirrhosis include avid sodium reabsorption, impaired concentrating and diluting abilities, and partial renal tubular acidosis. Fluid and electrolyte disorders are common. Sodium retention with edema and ascites should generally be treated conservatively because they tend to disappear as the liver heals and because forced diuresis has hazards. The indications for diuretics are (1) incipient or overt atelectasis; (2) abdominal distress; and (3) possibility of skin breakdown. Hyponatremia is common and its mechanism and treatment must be assessed in each patient. Hypokalemia occurs and requires treatment. Respiratory alkalosis and renal tubular acidosis seldom need therapy. The hepatorenal syndrome is defined as functional renal failure in the absence of other known causes of renal functional impairment. The prognosis is terrible and therapy is unsatisfactory. The best approach is not to equate the occurrence of renal failure in cirrhosis with the hepatorenal syndrome. Rather the physician should first explore all treatable causes of renal failure, eg, dehydration, obstruction, infection, heart failure, potassium depletion, and others.
Ascites↗