Recognised causes of proximal type II Renal Tubular Acidosis (RTA) include :
1. Amyloidosis
2. Heavy metal poisoning
3. Renal transplant rejection
4. Hyperparathyroidism
Select the correct answer using the code given below :
Understanding Proximal Type II Renal Tubular Acidosis (RTA)
Proximal type II Renal Tubular Acidosis (RTA) is a condition where the proximal tubules of the kidneys are unable to properly reabsorb bicarbonate ($HCO_3^-$) from the filtrate back into the blood. This leads to bicarbonate loss in the urine and resulting metabolic acidosis.
Evaluating Causes of Proximal RTA
We need to identify which of the listed conditions are recognized causes of proximal RTA:
- 1. Amyloidosis: This condition involves abnormal protein deposits (amyloid) in organs, including the kidneys. Amyloid infiltration can damage the renal tubules, particularly the proximal tubules, impairing their function and leading to proximal RTA. Therefore, Amyloidosis is a recognized cause.
- 2. Heavy metal poisoning: Exposure to heavy metals (e.g., lead, cadmium, mercury) can be directly toxic to the proximal tubules. This toxicity can cause a general dysfunction of the proximal tubule, including impaired bicarbonate reabsorption, resulting in proximal RTA. Thus, Heavy metal poisoning is a recognized cause.
- 3. Renal transplant rejection: While kidney transplant rejection severely impacts overall kidney function, it is not typically listed as a primary or specific cause of proximal type II RTA. The damage is often more widespread or involves different mechanisms than those causing isolated proximal tubule defects.
- 4. Hyperparathyroidism: This condition is primarily associated with distal (Type 1) RTA, not proximal (Type II) RTA. It affects the kidney's ability to secrete hydrogen ions ($H^+$) or generate/reabsorb bicarbonate in the distal nephron segments.
Conclusion
Based on the analysis, the recognized causes of proximal type II RTA from the list are Amyloidosis (1) and Heavy metal poisoning (2).
Therefore, the correct option includes items 1 and 2 only.
Important Questions from Acid-Base Disorders
- The most common acid-base disturbance in critically ill patients is :
- Salicylate intoxication in adults usually causes:
1. Severe respiratory alkalosis.
2. Mixed metabolic acidosis respiratory alkalosis.
3. Hyperchloremic metabolic acidosis.
Select the correct answer using the code given below - Which one of the following pairs is not correctly matched?
Consider the following:
1. Normal anion gap
2. Hyperchloraemic acidosis
3. Inappropriately high urinary pH (>5.4)
Which of the above are the characteristic features of renal tubular acidosis (RTA)?- Which one of the following is not an example of metabolic acidosis with high anion gap?
