Disorders of acid-base balance

METABOLIC ALKALOSIS IN A PATIENT WITH RENAL FAILURE: ROLE OF ANTACIDS

A 75-year-old patient with anuric renal failure developed a significant metabolic alkalosis thought to be due to the enteral absorption of "nonsystemic" antacid administered in large daily doses for prevention of recurrent peptic ulcer disease.

Hypokalemia--clinical spectrum and etiology

This paper is intended to give a review of the etiology and symptoms of potassium deficiency in man, as an introduction to the section on potassium and cardiac arrhythmias of this symposium. A review is given of different conditions where hypokalemia and/or total potassium deficiency is or might be part of the clinical picture, such as conditions with insufficient dietary intake, gastrointestinal potassium losses (e.g. vomiting, fistulas, malabsorption, abuse of laxatives and diarrhea), and renal potassium losses (e.g. primary and secondary hyperaldosteronism, Cushing's syndrome, intake of licorice, diabetic coma, renal disease, diuretic treatment and l-dopa treatment). Common symptoms of hypokalemia and/or potassium deficiency are reviewed as well, such as general and unspecific symptoms (e.g. tiredness, lack of concentration, lack of appetite and vomiting), and symptoms from the heart, kidneys and skeletal muscle.

[Effects of water diuresis on the urinary ph of patients under relapsing lithiasis]

INTRODUCTION

It has been observed that in healthy individuals the increase in urinary flow induced by water overload may be enough to alter the urinary Ph to obtain values considered safe in the prophylaxis of lithogenesis. The aim of the present paper is to determine the effects of water diuresis on the urinary Ph of patients suffering from relapsing lithiasis.

MATERIAL AND METHOD

26 patients were included in the present study. The urinary Ph of all patients was measured along two consecutive days, at 8.30 and again at 12.30, under normal conditions (the first day) and once they had received a water load equivalent to 1.5% of their weight (the second day).

RESULTS

The altered mean value of the Ph induced on the first day by the circadian rhythm showed a mean of 0.13 units of Ph, which lacks statistical significance (p > 0.05). However, on the second day we obtained a value of 0.42, which is statistically significant (p < 0.01). The normal tendency after the water overload was towards a positive increase of the Ph in those patients whose urine showed a preload Ph value < 6.1, whereas those individuals with a preload Ph value > 6.48 suffered negative increases.

CONCLUSIONS

The increase of diuresis induced by water load proved enough to provoke an increase of urinary Ph when its baseline value is < 6.1, or either a decrease when its baseline value is > 6.48. In both cases, Ph values ranged between 6-6.5 which are considered safe values in the prophylaxis of lithogenesis. The more separated the baseline urinary Ph is from the 6.1-6.48 range, the greater the effect of the water load.

Ascites, renal abnormalities, and electrolyte and acid-base disorders associated with liver disease

Ascites and renal dysfunction are often associated with decreased liver function and reflect the complex abnormalities of water, protein, electrolyte, and acid-base metabolism that may complicate severe liver disease. This article discusses the pathophysiology and management of ascites, polydipsia and polyuria, decreased renal function, and acid-base and electrolyte alterations that can complicate liver disease.

Control and prevention of tuberculosis: a code of practice

The Joint Tuberculosis Committee has compiled a report that is designed to answer the questions most commonly asked about the control and prevention of tuberculosis. Advice is given on assessing the degree of infectivity and on the segregation of patients. The measures necessary to protect National Health Service workers depend on the risk of exposure, and health authorities should follow the advice given by the Department of Health and Social Security. Chest x ray examinations may be recommended for those entering the teaching profession and may be necessary for staff and children when tuberculosis is discovered in a school child. The diagnostic, protective, and therapeutic measures required for contacts depend on the degree of infectivity in the index case, the closeness of contact, and the ethnic group of the index case. The incidence of tuberculosis is much higher among some immigrant populations than among the native population and screening programmes are needed (a) to detect cases of active tuberculosis, (b) to identify infected individuals without active disease, and (c) to identify those in need of vaccination. Finally, the current recommendation that BCG vaccinations should be offered routinely in schools to children aged 10-14 has been highly effective in preventing tuberculosis and should be maintained.

The acidosis of chronic renal failure

The acidosis of chronic renal failure is not due to bicarbonate wastage per se; rather, bicarbonate reabsorption per nephron is markedly enhanced. The ability to lower the urine pH is preserved. While overall ammonium production may be decreased in chronic renal failure, both ammonium production and excretion are markedly increased when expressed per remaining nephron. Titratable acid excretion in chronic renal failure is essentially maximal, owing to the effect of parathyroid hormone on phosphate excretion by the kidney. Thus, it appears that the acidosis of chronic renal failure is solely the consequence of the reduction in functional renal mass. Extrarenal buffering may contribute substantially to the maintenance of a near normal acid-base status in patients with marked reduction in glomerular filtration rate. That homeostasis is so well preserved until glomerular filtration rate falls to approximately 10 per cent of normal is remarkable; the price, however, may be considerable. Prolonged acidosis may magnify the tendency of renal failure to cause osteodystrophy. An obvious treatment for the acidosis of renal failure is exogenous alkali therapy. Most clinicians withhold alkali therapy until the bicarbonate concentration falls below 20 mEq per L. If the acidosis cannot be safely corrected with exogenous therapy, dialysis should be initiated.