Renal tubular acidosis
| Classification according to ICD-10 | |
|---|---|
| N25.8 | Other diseases resulting from damage to the tubular kidney function |
| N25.8 | Renal tubular acidosis type 1 [Lightwood-Albright syndrome] |
| N25.8 | Secondary hyperparathyroidism of renal origin |
| ICD-10 online (WHO version 2019) | |
Under a renal tubular acidosis (synonym: RTA , including Butler-Albright syndrome Lightwood , English : Renal Tubular Acidosis ) are the specific disorders renal (via the kidneys) acid excretion understood.
Classification
Three different forms can be differentiated:
- Renal tubular acidosis type I (distal tubular secretion disorder for protons)
- Renal tubular acidosis type II (proximal tubular re-absorption disorder for bicarbonate due to carbonic anhydrase deficiency )
- (Type III is a mixture of types I and II)
- Type IV renal tubular acidosis (hyperkalemic acidosis)
This group of diseases can be congenital tubular dysfunction. After a urinary tract infection has been ruled out, urine pH values that are always above 5.8 (urine pH daily profile!) Are indicative of renal tubular acidosis . In the presence of renal tubular acidosis, administration of 0.1 g / kg / body weight (1.9 mmol ) of ammonium chloride does not lead to a drop in the pH value below 5.5.
Renal tubular acidosis type I (distal RTA)
In this disease, the urine is only insufficiently acidified ( urine pH > 6) due to a disturbance in the secretion of H + in the area of the distal tubules , although systemic acidosis occurs. There are not enough H + - ions ready for the formation and reabsorption of bicarbonate. As compensation, cations are excreted with potassium and sodium . The clinical focus is on hyperaldosteronism, volume depletion , hypercalciuria , hypokalaemia and hyperchloremic, metabolic acidosis with normal anion gap . The chronic course is often associated with complications from nephrolithiasis (kidney stones) and nephrocalcinosis .
Treatment is carried out by supplementing with potassium and administering sodium hydrogen carbonate or citrates .
Renal tubular acidosis type II (proximal RTA)
The excessive bicarbonaturia typical of this clinical picture is the result of a persistent re-absorption defect in the proximal tubule for bicarbonate, which causes chronic metabolic acidosis . The loss of sodium and potassium, volume depletion and the activation of the renin-angiotensin-aldosterone system (RAAS) are of clinical relevance . The consecutive hyperaldosteronism leads to an increased reabsorption of sodium, which increases the potassium losses. The distal tubular mechanisms of uric acidification remain intact, so that the additional acidic valences are excreted in the urine. The most important symptoms in children are stunted growth and rachitic changes, in adults osteoporosis or osteomalacia occurs . Nephrolithiasis and nephrocalcinosis, as can occur in type I, are typically absent.
Treatment consists of taking large amounts of sodium citrate or sodium lactate . Potassium-sparing diuretics such as triamterene are said to be able to reduce renal bicarbonate loss.
Type IV renal tubular acidosis
This variant is based on a reduced reabsorption of sodium in the area of the distal tubule , in which H + ions and potassium are only insufficiently secreted in the tubular form. Hyperkalemic renal tubular acidosis develops, the primary defect of which is based on an aldosterone deficiency or aldosterone resistance . When exposed to acid, the urine can normally be acidified, the titration acidity is reduced due to the reduced ammonium formation . In children with normal kidney function, this disorder is observed in the event of severe sodium loss, and in adult patients in the case of significant renal impairment.
The therapeutic goals are to avoid life-threatening hyperkalemia with a low-potassium diet and avoid potassium-sparing diuretics.
Individual evidence
- ^ W. Pschyrembel: Clinical dictionary. 265th edition. Verlag Walter de Gruyter, 2014, ISBN 978-3-11-018534-8 .
- ↑ Eva Andreas, Malte Sönnichsen, Ulf Kächler, Dettmer Folkerts: Intensive course in biochemistry with StudentConsult access . Urban & Fischer in Elsevier, Munich 2006, ISBN 3-437-44450-6 .
- ↑ a b c M. Classen, V. Diehl et al. (Ed.): Internal medicine with StudentConsult access . Urban & Fischer in Elsevier, Munich 2006, ISBN 3-437-44405-0 .
- ↑ Specialist information on Dyrenium compositum in the Swiss drug compendium
literature
- Beatrice R. Amann-Vesti: Clinical pathophysiology: 239 tables . Thieme, Stuttgart / New York 2006, ISBN 3-13-449609-7 .
Web links
- Metaphylaxis of urinary calculus guidelines of the German Society for Urology
