Aluminum bone disease

Chronic renal failure can cause renal osteodystrophy. One type is osteitis fibrosa caused by secondary hyperparathyroidism (SHPT), a high-turnover bone disease; another is a low-turnover bone disease presenting as osteomalacia, mostly due to aluminum deposition in bone, called aluminum-related bone disease. A third type shows both changes, called mixed osteodystrophy.

Common Symptoms

Weakness; tremor; progressive dementia; dementia; stuttering; myoclonus; confused thinking; disorientation

Causes

When dialysate aluminum approaches 50ug/L, aluminum-related bone disease is common, so some authors recommend dialysate aluminum at least below 10ug/L, preferably below 5ug/L; using reverse-osmosis water has greatly reduced this source of aluminum toxicity. For example aluminum hydroxide: after oral intake only a little aluminum is absorbed, but the kidney is the only excretion route, so in chronic renal failure absorbed aluminum accumulates and causes toxicity; sucralfate for peptic ulcer is also a cause; orange juice containing aluminum and sodium citrate promotes aluminum absorption, as does calcium citrate; lower gastric pH increases aluminum solubility, suggesting gastric pH changes absorption, so the H2 blocker ranitidine is thought to reduce aluminum toxicity in chronic renal failure. In China, using aluminum ware (pots, kettles, woks) for cooking and regularly eating aluminum-containing foods (fried dough cakes, fried dough sticks) may also cause excess intake. For example albumin. Because aluminum and iron share pathways in intestinal absorption, serum transport and cellular uptake, iron stores affect aluminum kinetics, so iron deficiency may increase aluminum toxicity risk; adequate iron stores seem protective. Some people have low bone remodeling and/or low parathyroid hormone, including parathyroidectomy patients, renal transplant rejection treated with corticosteroids, diabetes, marked PTH decline after dihydroxycholecalciferol, and bilateral nephrectomy, making them more sensitive to aluminum toxicity. In end-stage renal disease aluminum excretion is impaired, worsening accumulation, and total-body aluminum can be 20 times normal; bone, liver and spleen accumulate the most; increased bone aluminum relates to toxicity and causes aluminum-related bone disease, though high liver and spleen aluminum does not cause toxicity. Pathogenesis: osteomalacia is characterized by low bone turnover, reduced bone-forming and resorbing cells, and increased unmineralized bone volume; vitamin D deficiency was once thought important, but most modern reports attribute it to aluminum toxicity. Aluminum mainly deposits at the calcified-bone edge (the mineralized/unmineralized interface) causing osteomalacia, and the severity of histological changes relates to the degree of edge deposition; aplastic bone disease may precede aluminum-induced osteomalacia. Aplastic bone disease was first reported in 1982 as a renal osteodystrophy, now considered a major bone lesion in chronic renal failure patients on peritoneal dialysis; some cases result from excess aluminum accumulation, but excessive PTH suppression may be more important. PTH is important for normal bone metabolism, possibly preventing aluminum deposition at the mineralization front by increasing bone turnover, while parathyroidectomy is a risk factor for aluminum-related bone disease by reducing bone formation and turnover and letting aluminum accumulate at the calcified edge, disturbing mineralization. Clinically, in secondary hyperparathyroidism, aluminum-related bone disease should be excluded before parathyroidectomy, because lowering PTH accelerates aluminum deposition in bone and the onset of aluminum-related bone disease.

Treatment

Medication, rehabilitation therapy

Prevention

Preventing aluminum-related disease is not easy; the following may be considered. 1. Avoid aluminum-containing phosphate binders; use calcium carbonate or calcium acetate instead. 2. Use reverse-osmosis water for dialysate. 3. Avoid aluminum ware for boiling and cooking, and avoid high-aluminum foods such as fried dough cakes and fried dough sticks.

Recommended Department

It is recommended to visit the orthopedic surgery department; before the visit you may first book an appointment and connect with experts through this platform.

Warm reminder: The above information is provided for health education reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek care at a regular hospital in time.