26th June 2023

Diagnosis

The diagnosis of chronic tubulointerstitial nephritis is normally a clinical diagnosis based on the possible underlying cause, the presenting features, examination findings and clinical judgement; however, there are some clinical tests to aid in the diagnosis.

• Urinalysis – proteinuria, leukocytes, occasional white cell casts
• Blood tests
  • Evidence of normocytic anemia is often disproportionate compared to the extent of the reduction in the glomerular filtration rate caused by reduced production of erythropoietin.
  • Increased urea and creatinine
  • Abnormal electrolytes – hypokalaemia, hyperkalaemia, hypocalcaemia, hypomagnesaemia, hyponatraemia
  • Metabolic acidosis – normal anion gap metabolic acidosis secondary to renal tubular acidosis
• Ultrasonography
  • Small kidney, increased echogenicity, scarring