Natural history of primary distal renal tubular acidosis treated since infancy

Clinical and pathophysiologic studies were performed in five unrelated children with primary distal renal tubular acidosis who were diagnosed during infancy and followed for 3 to 9 1/2 years. All patients had permanent defects in hydrogen ion secretion, sodium reabsorption, and concentrating capacity. A transient, age-related, proximal tubular defect in sodium and bicarbonate reabsorption was also present. Renal bicarbonate wasting was mainly observed during the first years of life and progressively decreased with advancing age. Glomerular filtration rate remained within normal limits. Following sustained therapy with sodium and potassium bicarbonate, the patients had optimal growth, arrest of progression of nephrocalcinosis, and lack of other characteristic features of the disease with the exception of polyuria. Dosage of alkali was mainly determined by the magnitude of the renal bicarbonate loss and decreased progressively from a maximum of 3.9 to 10.0 mEq/kg/day during the first year of life to about 3 mEq/kg/day at or beyond 6 years of age. The total dosage of alkali required could be derived by the sum of the urinary excretion of bicarbonate plus 2 mEq/kg/day, which represents mean endogenous acid production. Although calciuria was normal when metabolic acidosis was corrected, patients with higher urinary sodium excretion had higher urinary excretion of calcium and thus were at greater risk of developing nephrocalcinosis if therapy was not carefully controlled.

Elevation of the blood lactate concentration by alkali therapy without requiring additional lactic acid accumulation: theoretical considerations

A patient presented with lactic acidosis and severe acidemia; sodium bicarbonate was administered to titrate the very large hydrogen ion load. Coincident with this therapy, the blood lactate concentration rose from 21 to 27 mmole/L. In order to evaluate whether this rise in lactate could have occurred without requiring additional net lactic acid production, the effect of the hydrogen ion concentration on lactate distribution was evaluated. Data obtained from animal studies support the established hypothesis that lactate is distributed like other weak organic acids at steady-state; hence, alkalemia should favor a shift of lactate from the intracellular fluid (ICF) to the extracellular fluid (ECF). The authors calculated that the blood lactate concentration could rise by 50% without requiring net lactic acid accumulation when the severe acidemia was corrected by alkali therapy. Thus, an increase in lactate concentration of the magnitude observed during alkali therapy need not indicate a worsening of the metabolic picture in lactic acidosis.

[Oxalate stone prophylaxis by alkalinizing therapy (author's transl)]

Hypocitraturia was found in 75% of oxalate stone formers, and combined with hypercalciuria in 27%. By short-term alkalinizing therapy (3 weeks) with sodium-potassium-citrate (Uralyt-U) a 118% increase in citrate- and a 29.5% decrease in calcium excretion could be achieved in 71 patients. There was no change in the 24 h urinary excretion of oxalate, urate, magnesium and phosphate. In 10 recurrent oxalate stone formers long-term (10 to 20 months) alkalinizing therapy was performed. The quantitative effect on the excretion of citrate and calcium remained unchanged. Seven patients, who have completed at least one year of therapy have had no recurrence of stones.

Change of urinary excretion of electrolytes after acid, base and furosemide application in sponge kidney

Sponge kidney is rare clinical and pathological entity, incidentally found in 0.4--1% of all excretory urographies. In the advanced stage of the disease, distal tubules are affected and renal-tubular acidosis, change of urinary laminar flow and Ca2+ wasting syndrome result in frequent formation of Ca-oxalate stones. Alkali therapy is investigated on the excretion of Na+, K+ and Ca2+ and compared to furosemide administration.

Materials and methods for cleaning dentures

Proper hygienic care of removable dentures is an important means of maintaining a healthy oral mucosa in denture wearers. Denture cleanliness is often poor due to improper mechanical cleansing and the relative inefficiency of most commercial products for chemical cleansing of dentures. Dentists and patients should realize that microbial plaque on dentures may be harmful to both the oral mucosa and the patient's general health. It is the responsibility of the patient to maintain oral hygiene through a daily home care routine. It is the obligation of the dentist to motivate and instruct the patient and provide the means and methods for plaque control. Future research should be directed to developing solution cleansers which can maintain plaque-free dentures with a daily soaking period of 15 to 30 minutes and not affect the color and surface luster of the denture acrylic resin.

[Prophylactic alkalization of the urine during cytostatic tumor treatment with the oxazaphosphorine derivatives, cyclophosphamide and ifosfamide]

The so-called cystitis due to cyclophosphamide (Cytoxan) is caused by direct contact of the mucosa with alkylating metabolites in acid urine. These alkylating metabolites can be inactivated by instillation of cysteine into the urinary bladder. The cytostatically active metabolites of ifosfamide (Holoxan), a derivative of oxazaphosphorine, are eliminated by the kidneys as well. Their special toxicity is much higher than the toxicity of Cytoxan. The alkylating metabolites of ifosfamide cause urological complications essentially in supravesical areas (tubulopyelo-ureteritis). Some clinical trials demonstrate that increase of diuresis and alkalinization of urine by orally administered Uralyt-U are able to decrease concentration and aggressiveness of those metabolites.

The metabolic situation in ureterosigmoidostomy

At reexamination 67 patients with ureterosigmoidostomies showed no significant alteration of their acid-base and electrolyte metabolism as compared to the preoperative situation and 39 patients with a colonic conduit. If required these patients had received an oral alkali substitution therapy; this proved to be necessary as a permanent measure only in cases with functional and morphological defects of the upper urinary tract. Spells of hyperchloremic acidosis had occurred in 13 patients during the follow-up period and always coincided with attacks of acute pyelonephritis and renal deterioration, often accompanied by irregularities in the substitution. Obviously metabolic problems arise only with a deteriorating urinary tract and timely discovery and treatment of these patients is the main task of the supervising doctor. Although the metabolic imbalances usually respond promptly to an adaptation of the substitution therapy, patients with a predamaged upper urinary tract should not be subjected to ureterosigmoidostomy.

The use of percutaneous nephrostomy and urinary alkalinization in the dissolution of obstructing uric acid stones

Two patients are described who presented with complete urinary obstruction secondary to nonopaque uric acid stones. They were treated with percutaneous nephrostomy for urinary diversion and urinary alkalinization by local irrigation and oral sodium bicarbonate therapy with complete dissolution of the stone after 16 and 21 days of therapy. Percutaneous nephrostomy with urinary alkalinization is a reasonable, relatively safe alternative to surgical stone removal for patients with obstructing uric acid stones.

Acidosis and growth in nonuremic renal disease

Our data demonstrate that correction of acidosis is sustained in children with type 1 RTA when alkali therapy is given in doses of 5 to 14 mEq/kg/day. The large doses are required as a result of renal bicarbonate-wasting. Children with type 1 RTA and acidosis who have significant growth impairment experience catch-up growth and attain normal stature for their age when correction of acidosis is sustained. Whether chronic acidosis impairs growth in any clinical condition except type 1 RTA is not settled. Whether sustained correction of acidosis with alkali therapy will allow attainment of normal stature in children with nonuremic diffuse renal disease is not yet determined. With the increasing availability of microchemistry and microgasometry and the new standards for growth based on mean-parent height [40], it can be anticipated that answers to these clinically important questions will be forthcoming.

[Complication caused by abuse of alkalies in the treatment of ulcers]

The authors report the case of a 57 year old man who had taken for several years large quantities of alkaline drugs to relieve pain due to a gastric ulcer. This man presented acute digestive symptoms, and a confusional syndrome explained by various metabolic disturbance and especially hypercalcemia at 145 mg. Stopping the alkalis permitted within a few days the disappearance of the clinical symptoms and the correction of the laboratory disturbances. In the light of this case, the authors study the main clinical cases which have been described either in their acute form or in their chronic form (Burnett's syndrome). They discuss above all the physiopathology of these manifestations and it seems to them that the hypercalcemia is more important than the alkalosis. It remains to be explained why only a small number of subjects are exposed to these metabolic complications. There seems to be an individual hypersensitivity for under normal conditions, excess calcium is not sufficient to induce hypercalcemia.

Acute acid-base disorders. 2. Specific disturbances

Evaluation of the acid-base status of the body requires measurement of bicarbonate (total carbon dioxide) concentration, pH, and partial pressure of CO2 in arterial blood. Calculation of standard bicarbonate and base excess or deficit is not necessary. The normal concentration of free hydrogen ions (H+) is approximately 40 millimoles/liter, which is equivalent to a pH of 7.4. The normal load of fixed acids is 50 to 80 millimoles in 24 hours. A steady state is maintained by excretion of an equal amount of H+ by the kidneys, which at the same time regenerate bicarbonate to replenish buffer stores. Renal excretion of H+ is in the form of titratable acid and ammonium. Synthesis of ammonia can increase severalfold under the stimulus of acidosis. This is the chief mechanism of long-term compensation. Metabolic acidosis can be due to an excessive acid load (endogenous or exogenous), impaired renal excretion of H+, or bicarbonate loss. Determination of the "anion gap" (unmeasured anions) helps to establish the mechanism of acidosis. Acidosis with a normal anion gap is due to either bicarbonate loss or ingestion of certain chloride salts. A gap larger than normal indicates the presence in the body of acids other than acidfying chloride salts. Management of metabolic acidosis requires accurate diagnosis, clear understanding of the mechansim, and individualized treatment. Metabloic alkalosis is due to loss of H+ (usually from stomach or kidneys) or ingestion of alkali. Measurement of urinary chloride helps establish the mechanism of alkalosis. In saline-responsive alkalosis, the urinary chloride level is very low. This is usually due to gastric loss of H+, and the condition responds to administration of saline solution. When the urinary chloride level is only moderately low, the alkalosis is probably not due to gastric loss of H+. This form of alkalosis (saline-resistant) does not respond well to administration of saline solution and requires use of potassium in treatment. Apprpriate compensatory responses to acidosis or alkalosis are critical to survival. Compensation for metabloic acidosis consists of hyperventilation and enhanced renal excretion of H+, chiefly as ammonium. In metabolic alkalosis, compensation is mainly renal excretion of bicarbonate. Respiratory acidosis is due to alveolar hypoventilation. In chronic situations, a compensatory rise in serum bicarbonate concentration is expected. Management consists of treatment of the cause of hypoventilation. Respiratory alkalosis is due to hyperventilation. Treatment requires identification and correction of the cause of hyperventilation.

Follow-up of 13 children after ureterosigmoidostomy

Follow-up of 13 children who had had a ureterosigmoid anastomosis 3 1/2 to 10 years previously and whose initial urogram had been satisfactory, showed that growth was normal and that there was no serious metabolic disorder. In particular whole-body potassium did not differ significantly from normal values (as given by Langham, 1961). Asymptomatic urinary infection is the chief hazard in these cases but is difficult to diagnose and may lead to progressive dilatation of the ureters.