• Clinical science

Tubulointerstitial diseases

Abstract

Tubulointerstitial diseases are characterized by acute or chronic inflammation of the renal tubules and interstitium. Acute interstitial nephritis is commonly caused by allergic reactions to drugs, but infection or systemic disease may also precipitate the disease. Common causes of chronic nephritis include drug toxicity (especially analgesics), metabolic disease (e.g., uric acid nephropathy), and other underlying conditions (e.g., multiple myeloma). Typical symptoms in both acute and chronic nephritis are painless hematuria (without RBC casts!) and pyuria. Depending on the underlying disease, nephritis may present with additional symptoms such as rash, arthralgias, and fever in the case of allergic interstitial nephritis. The most important diagnostic modalities are lab tests (increased blood urea nitrogen and creatinine) and urinalysis, although a kidney biopsy may be indicated in select cases. Treatment usually consists of supportive measures and addressing the underlying cause (e.g., discontinuing medication). All diseases affecting the renal tubules can ultimately lead to chronic renal failure.

Acute tubulointerstitial nephritis

Acute tubulointerstitial nephritis is most commonly caused by a hypersensitivity reaction to drugs (allergic interstitial nephritis). Some drugs may also lead to crystal-induced acute kidney injury.

Allergic interstitial nephritis

Crystal-induced acute kidney injury

Etiology
Pathophysiology
  • Drugs with low urine solubility precipitate within the renal tubules→ tubular obstruction & toxicity to tubules
Symptoms
  • Patients are usually asymptomatic
  • Renal colic
Diagnostics
  • Crystals on brightfield microscopy
Therapy
Prognosis

Other etiologies

References:[1][2][3]

Chronic tubulointerstitial nephritis

The most common cause of chronic interstitial nephritis is analgesic nephropathy. Multiple myeloma can also be the cause.

Analgesic nephropathy

Myeloma kidney (myeloma cast nephropathy)

Etiology
Pathophysiology
  • Excessive amounts of light chains are produced and filtered into the primary urine → precipitation of light chains in renal tubules → tubular obstruction & toxicity to renal tissue
  • The increased number of light chains may also lead to deposits in the glomeruli (→ light chain deposition disease)
Clinical features
Therapy
  • See “Treatment” below
Prognosis

Other etiologies

References:[2]

Renal papillary necrosis

Causes of renal papillary necrosis: POSTCARDS (pyelonephritis, obstruction, sickle cell disease, tuberculosis, cirrhosis, analgesics, renal transplant rejection, diabetes mellitus, systemic vasculitis)


References:[4][5]

Diagnostics

References:[1][3][4;306][4]

Treatment

For all tubulointerstitial diseases:

  • Treat underlying disease
  • Monitor kidney function
  • Consider glucocorticoids
  • In select cases, (temporary) dialysis

References:[6]