What Are Kidneys?
The kidneys are a pair of organs located below the rib cage on either side of the lower abdomen. They are almost always found in pairs in most people. Kidneys perform critical activities such as blood purification and waste removal from the body through urine. Glomerular filtration is the term for this process. Urine is subsequently transported to the bladder via the ureters. Hormones help to control blood pressure.
Drug and toxin-induced nephropathy can result in acute kidney injury (AKI) or proximal tubule injury, which leads to inflammation of the glomerulus of the kidney resulting in infiltration of the blood inside the body and further leading to kidney failure. Certain drugs act as a toxin in the kidney, which results in kidney impairment and deterioration of kidney function.
What Is Nephropathy?
Nephropathy is a kidney disorder caused by a medical condition, immunological malfunction, or exposure to toxins. Nephropathy is a group of diseases that affect the kidneys. Diabetic nephropathy is a type of nephropathy that is most commonly associated with diabetes.
IgA nephropathy, commonly known as Berger's disease, is a kidney disease caused by IgA antibodies accumulating in the kidneys, causing inflammation and tissue destruction. Toxic nephropathy is a term that describes any functional or structural abnormalities in the kidney caused by a chemical or biological product that is inhaled, swallowed, injected, or absorbed and causes kidney damage.
What Are Drugs and Toxins Causing Nephropathy?
Various drugs and different substances are absorbed by the nephrons, which, when altered in dosage, can lead to nephrotoxicity. Nephrons are the filtering units of the kidney that, when deposited with certain substances, lead to nephrotoxicity. Toxic nephropathy is primarily a kidney injury caused by any number of medications, diagnostic agents, herbal adulterants, or other toxin exposures, which include environmental agents and chemicals; adverse renal effects occur when physiologic substances circulate through the body in a greater or lesser than normal concentration. Examples are carcinogens, drugs, environmental pollutants, food additives, hydrocarbons, and pesticides. These compounds get deposited inside the renal tubules leading to toxicity of the nephrons.
Drugs Causing Nephropathy-
Many drugs produce crystals that are insoluble in the urine and precipitated within distal renal tubules, thus, causing an obstruction. The drugs that generate crystals are- Sulfonamides, Ampicillin, Acyclovir, Ciprofloxacin, Methotrexate, and Triamterene, mainly precipitated in acidic urine in patients with renal impairment. Drug-induced endothelial cytotoxicity is caused by drugs such as Ticlopidine, Cyclosporine, and Quinine. Antimicrobial agents like Aminoglycosides, and Amphotericin B, cause injury to the distal tubule, whereas Tenofovir, Cidofovir, and Adefovir primarily injure the proximal tubule as well as the distal tubule.
What Are the Risk Factors for Nephropathy?
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Older age.
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Female sex due to hormonal disturbances.
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Heart failure.
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Decreased total-body water, which is associated with a drug overdose.
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Diabetes.
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Infection or sepsis.
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Patients are already suffering from kidney diseases.
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Lower glomerular filtration rate (GFR) because of lower serum creatinine and lower protein intake.
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Renal vasoconstriction from excessive angiotensin II and endothelin (kidney ischemia) and higher concentrations of oxidatively modified biomarkers are present in the increased risk of drug nephrotoxicity.
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Ischemia of tubular cells.
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Tubular injury from bile salts (obstructive jaundice).
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Elevated uric acid levels or hyperuricemia.
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Prior exposure to contrast media for X-ray or CT scans.
How to Diagnose Nephropathy?
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Blood Test-
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GFR Test - To know the blood filtering efficiency of the kidney.
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Serum Creatinine Test - To check creatinine clearance from the blood.
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Blood Urea Nitrogen (BUN Test) - To evaluate the clearance of nitrogen from the blood.
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Cystatin C Test - Cystatin C is a protein produced by the cells in the body. The level of cystatin C in the blood determines the working condition of the kidneys. If the level of cystatin in the blood is too high, it may mean that the kidneys are not working well.
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Neutrophil Gelatinase-Associated Lipocalin (NGAL Test) - For quantitative determination of neutrophil gelatinase-associated lipocalin in blood serum.
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Urine Test - This test provides results for the presence of protein and red blood cells, urine specific gravity, total urine protein, and uric acid in the urine.
Kidney injury molecule-1 (KIM 1)- A soluble form of human KIM-1 can be detected in the urine and serves as a useful biomarker for renal proximal tubule injury. Kidney molecule injury-1(KIM-1), cystatin C, and neutrophil gelatinase-associated lipocalin (NGAL) levels in the serum are the markers of kidney failure and can detect acute kidney failure more sensitively than creatinine in the urine.
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Imaging Tests - Computerized tomography (CT) scans are one type of imaging exam.
Ultrasound of the kidneys is used to determine the size of the kidneys and the presence
of any obstructions.
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Kidney Biopsy - Fine needle aspiration cytology can be used to remove a portion of renal tissue by piercing it with a needle. The proportion of affected glomeruli (diffuse or localized) and the presence of hypercellularity are determined by a biopsy.
How to Treat Drug and Toxin-Induced Nephropathy?
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Renal failure can be prevented by maintaining water balance inside the body.
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Dialysis should be started if any signs of kidney failure are present. Dialysis is the process of filtering the blood outside the body. There are two types of dialysis - hemodialysis and peritoneal dialysis.
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Drugs causing nephrotoxicity should be changed, or their dosage should be altered.
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In certain conditions, steroid therapy can help.
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Maintaining electrolyte balance.
What Are the Preventative Measures for Nephropathy?
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Using effective but not nephrotoxic drugs.
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Estimation of underlying risk factors like diabetes mellitus, high blood pressure, and immunocompromised conditions due to some underlying disease.
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Assessment of renal function tests before the start of therapy.
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Modification of diet according to consulting a dietician.
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GFR tests are mandatory in patients with older age and underlying diseases.
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Using drugs according to the dosage provided by the physician.
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Adequate hydration.
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Treatment of previously known diseases.
Conclusion
Toxin and drug-induced nephropathy is irreversible kidney damage caused by some drugs or adulterants or chemicals. It can be prevented by maintaining water and electrolyte balance inside the body. Nephrotoxic drugs or the dose of the prescribed drugs should be changed accordingly if anything suspicious is found. Underlying risk factors should be treated earlier and should be prevented from worsening. In case of end-stage renal disease and kidney failure, dialysis or kidney transplant can be done. Overall health maintenance and diet, if followed properly, the disease progression can be slowed down.
