Chapter 146: Renal Tubular Disease

Tubulointerstitial diseases constitute a diverse group of acute and chronic, hereditary and acquired disorders involving the renal tubules and supporting structures (Table 146-1). Functionally, they may result in a wide variety of physiologic phenotypes, including nephrogenic diabetes insipidus (DI) with polyuria, non-anion-gap metabolic acidosis, salt wasting, and hypo- or hyperkalemia. Azotemia is common, owing to associated glomerular fibrosis and/or ischemia. Compared with glomerulopathies, proteinuria and hematuria are less dramatic, and hypertension is less common. The functional consequences of tubular dysfunction are outlined in Table 146-2.
TABLE 146-1: Principal Causes of Tubulointerstitial Disease of the Kidney
Toxins
Exogenous toxinsMetabolic toxins
 Analgesic nephropathya Acute uric acid nephropathy
 Lead nephropathy Gouty nephropathya
 Chinese herb nephropathy Hypercalcemic nephropathy
 Balkan endemic nephropathy Hypokalemic nephropathy
 Miscellaneous nephrotoxins (e.g., antibiotics, cyclosporine, radiographic contrast media, heavy metals)a,b Miscellaneous metabolic toxins (e.g., hyperoxaluria, cystinosis, Fabry’s disease)
Neoplasia 
Lymphoma 
Leukemia 
Multiple myeloma (cast nephropathy, AL amyloidosis) 
Immune Disorders 
Acute (allergic) interstitial nephritisa,bTransplant rejection
Sjögren’s syndromeHIV-associated nephropathy
Amyloidosis 
Vascular Disorders 
Arteriolar nephrosclerosisaSickle cell nephropathy
Atheroembolic diseaseAcute tubular necrosisa,b
Hereditary Renal Diseases 
Disorders associated with renal failureHereditary tubular disorders
 Autosomal dominant polycystic kidney diseaseBartter’s syndrome (hereditary hypokalemic alkalosis)
 Autosomal recessive polycystic kidney diseaseGitelman’s syndrome (hereditary hypokalemic alkalosis)
 Medullary cystic kidney disease
 Hereditary nephritis (Alport’s syndrome) 
Pseudohypoaldosteronism type I (hypotension/salt wasting and hyperkalemia)
Pseudohypoaldosteronism type II (hereditary hypertension and hyperkalemia)
 Liddle’s syndrome (hypertension and hypokalemia)
 Hereditary hypomagnesemia
 
Hereditary nephrogenic diabetes insipidus
 
 X-linked (AVP receptor dysfunction)
  Autosomal (aquaporin-2 dysfunction)
Infectious Injury
Acute pyelonephritisa,b
Chronic pyelonephritis
Miscellaneous Disorders
Chronic urinary tract obstructiona
Vesicoureteral refluxa
Radiation nephritis
aCommon.
bTypically acute.
TABLE 146-2: Transport Dysfunction in Tubulointerstitial Disease
DEFECTCAUSE(S)
Reduced GFRaObliteration of microvasculature and obstruction of tubules
Fanconi syndromeDamage to proximal tubular reabsorption of solutes, primarily glucose, amino acids, and phosphate; may also exhibit hypouricemia, proximal tubular acidosis, low-molecular-weight proteinuria
Hyperchloremic acidosisa1. Reduced ammonia production (CKD) or excretion (hyperkalemia)
 2. Inability to acidify the collecting duct fluid (distal renal tubular acidosis)
 3. Proximal bicarbonate wasting (proximal RTA)
Polyuria, isothenuriaaDamage to medullary tubules (thick ascending limb and/or collecting duct) and vasculature
Hypokalemic alkalosisDamage or hereditary dysfunction of the thick ascending limb or distal convoluted tubule (Bartter’s and Gitelman’s syndromes)
Magnesium wastingDamage or hereditary dysfunction of the thick ascending limb or distal convoluted tubules
HyperkalemiaaPotassium secretory defects including aldosterone resistance
Salt wastingDistal tubular damage with impaired sodium reabsorption
aCommon.
Abbreviations: CKD, chronic kidney disease; RTA, renal tubular acidosis.

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