What are the symptoms of renal tubular damage?

The renal tubules are an important part of the kidneys and have the functions of secretion and excretion. If the renal tubules are damaged, it will have a great impact on these two major functions of the human body. The main symptoms of renal tubular damage include oliguria, acute renal failure, nausea and vomiting, fatigue, weight loss, etc. In addition, symptoms of chronic TIN and chronic pyelonephritis may also appear, which will be described in detail below.

1. Clinical manifestations

The main clinical manifestations are oliguric or non-oliguric acute renal insufficiency, accompanied by nausea, vomiting, weight loss, abdominal pain, fatigue, fever, rash and joint pain. Combined renal tubular function damage may manifest as Fanconi syndrome, with the occurrence of glycosuria, aminoaciduria, phosphaturia and proximal renal tubular acidosis; it may also manifest as tubular proteinuria and disorders of water, electrolyte and acid-base balance.

Typical drug-related TIN often has a more characteristic course of disease. Renal insufficiency occurs 10 to 20 days after medication. Renal function can slowly recover after medication is stopped. However, when the sensitizing drug is used again, acute renal failure may occur within 2 to 3 days. About 75% of patients have fever symptoms, 30%-50% have transient erythematous rash, itching, maculopapular rash, etc., 30%-60% have peripheral blood eosinophilia, but only about 30% have all three symptoms (triad). Half of the patients have elevated serum IgE levels, and 15%-20% of patients have nonspecific joint pain.

2. Symptoms of chronic TIN

Patients with chronic TIN often lack subjective symptoms and often seek medical treatment due to unexplained increases in serum creatinine, urea nitrogen, and uric acid or disorders of electrolytes (especially potassium) and acid-base balance. Some patients may also experience extra-renal symptoms such as weight loss, fatigue, fever, rash, and joint pain, but generally without edema and hypertension. The clinical feature of chronic TIN is severe anemia that is disproportionate to the degree of chronic renal insufficiency. Renal tubular dysfunction is a characteristic change of chronic TIN, which is clinically manifested as glycosuria, aminoaciduria, small molecule proteinuria, phosphaturia, alkalinuria, hypophosphatemia, hypercalcemia, hyponatremia, hyper- or hypokalemia, and renal tubular acidosis. In addition, nocturia, polyuria, and low specific gravity urine may occur due to the concentration disorder caused by damage to the renal medulla and renal papilla.

3. Symptoms of chronic pyelonephritis

Symptoms of chronic pyelonephritis include fatigue, low fever, anorexia, low back pain, and other symptoms, accompanied by lower urinary tract irritation symptoms such as frequent urination, urgency, and pain when urinating. Acute attacks also appear from time to time. In the past, patients with a disease course of more than half a year or one year were considered chronic pyelonephritis. In recent years, it has been suggested that chronic pyelonephritis is only present when there is scarring of the renal pelvis and calyces, and intravenous pyelography shows deformation of the renal pelvis and calyces, hydrops, an uneven kidney appearance, or the two kidneys are of different sizes. There may also be renal tubular function damage, such as decreased concentrating function, hypotonicity, low specific gravity urine, increased nocturia, and renal tubular acidosis. In the late stage, glomerular function damage, azotemia and even uremia may occur. Many cases of renal hypertension are caused by chronic pyelitis. It is generally believed that the patient's hyperreninemia and the release of some vasoconstrictor polypeptides are related to vascular sclerosis, stenosis and other lesions. In a few patients, hypertension is improved after one diseased kidney is removed.