From the Guidelines
Tubulointerstitial diseases are a group of kidney disorders that primarily affect the tubules and interstitium of the kidneys, and their causes include genetic mutations, drug-induced nephrotoxicity, infections, autoimmune disorders, and metabolic disturbances, with effects ranging from mild kidney dysfunction to end-stage renal disease. These conditions can be acute or chronic and are characterized by inflammation, fibrosis, or atrophy of the renal tubules and surrounding interstitial tissue. Common causes include autosomal dominant tubulointerstitial kidney disease (ADTKD) 1, drug-induced nephrotoxicity, infections, autoimmune disorders, and metabolic disturbances. Symptoms may include decreased urine output, fluid retention, electrolyte imbalances, and in severe cases, acute kidney injury or chronic kidney disease.
Clinical Characteristics
The clinical characteristics of tubulointerstitial diseases vary depending on the underlying cause, but common features include:
- Positive family history in ADTKD 1
- Progressive loss of kidney function
- Bland urinary sediment
- Absent-to-mild albuminuria/proteinuria
- No severe hypertension during early stages
- Normal or small-sized kidneys on ultrasound
- Nocturia or enuresis in children due to loss of renal concentration ability
Diagnosis and Treatment
Diagnosis typically involves a combination of clinical presentation, urinalysis, blood tests, imaging studies, and sometimes kidney biopsy. Treatment depends on the underlying cause but often includes:
- Discontinuation of nephrotoxic medications if drug-induced
- Antibiotics for infectious causes
- Immunosuppressive therapy (e.g., corticosteroids, cyclophosphamide) for autoimmune-related cases 1
- Supportive care, including fluid and electrolyte management
Prevention and Management
Prevention strategies involve avoiding nephrotoxic medications when possible, proper hydration, and prompt treatment of underlying conditions that can lead to kidney damage. Regular monitoring of kidney function in at-risk individuals is also crucial for early detection and management. Understanding tubulointerstitial diseases is important for healthcare providers as they can lead to significant kidney dysfunction if not properly managed. Early recognition and appropriate intervention are key to improving outcomes and preserving renal function. According to the most recent study 1, the incidence of immune-related renal dysfunction is 2%-7%, and the most common pathology is acute interstitial nephritis (AIN), observed in 80%-90% of patients.
From the Research
Causes of Tubulointerstitial Diseases
- Tubulointerstitial diseases can be caused by various factors, including medications, infections, autoimmune and systemic diseases, environmental exposures, and idiopathic causes 2
- Early in the course of the disease, tubular malfunction is out of proportion to glomerular disease, and the early presentation may be inability to concentrate urine, salt wasting, distal or proximal renal tubular acidosis and/or Fanconi's syndrome 3
- Lupus nephritis (LN) is a major complication in patients with systemic lupus erythematosus (SLE) and can cause tubulointerstitial injury 4
Effects of Tubulointerstitial Diseases
- Tubulointerstitial diseases can lead to acute and/or chronic kidney disease 2
- Chronic tubulointerstitial nephritis may develop in patients with previous acute tubulointerstitial nephritis or may be the initial manifestation of an autoimmune, systemic, environmental, or metabolic process 2
- The extent of tubulointerstitial inflammation is an independent predictor of renal survival in lupus nephritis 4
- Progressive renal disease can lead to interstitial infiltration, fibrosis, tubular atrophy, and dilatation, which can ultimately result in end-stage renal failure 5
Diagnosis and Treatment
- Diagnosis of tubulointerstitial diseases can be challenging, and kidney biopsy is often required to accurately diagnose acute tubulointerstitial nephritis and guide management 2
- Early diagnosis and treatment can prevent or delay the progression of the renal disorder 3
- Treatment of tubulointerstitial diseases is often limited and primarily supportive, and kidney biopsy is needed less often for chronic tubulointerstitial nephritis 2
- New therapeutic approaches are being developed to limit the progressive nature of fibrogenesis in renal disease 5