Symptoms in 4 Stages of Amyloid Nephropathy

Amyloid nephropathy is renal lesions caused by the deposition of large amount of amyloid fiber in the kidneys. Due to immune dysfunction, disorder of protein metabolism or degeneration decomposition of connective tissues, excessive amyloid fiber will be formed and its solubility in the physiological solution is very low. It will deposit in tissues and outside the cells resulting in organ compression, atrophy and dysfunction. In addition, some abnormal protein can act as antibodies and have specific immune response with these tissues and organs.

Its clinical manifestation is mainly nephrotic syndrome and will in the end develop into renal failure. Amyloid nephropathy can be divided into 4 stages according to the severity of the illness conditions and each has different symptoms.

1. Preclinical stage. This stage has no special signs and features and there is no symptoms even in tests. It can only be diagnosed by renal biopsy and this stage can last for as long as 5 to 6 years.

2. Proteinuria stage. Proteinuria is the earliest symptom and about 76% patients have protein in urine. In more than half cases the protein in urine is large molecular and low selectivity. The severity of proteinuria is related to the deposition part and degree of amyloid protein in renal glomeruli and it can be asymptomatic proteinuria and can last for years. Microscopic hematuria and cellular cast are rare. 20% to 50% have combined hypertension and the orthostatic hypotension is the characteristic sign of autonomous neuropathy.

3. Nephrotic syndrome stage. Massive proteinuria, hypoalbuminemia, edema and hyperlipidemia are rare and a few only have persistent small amount of proteinuria. Renal vein thrombosis is the most common complication of nephrotic syndrome and the onset of most cases is dormant. A few case will have acute onset and have the symptoms of abdominal pain, worsened hematuria, increased proteinuria, enlarged kidneys. Once nephrotic syndrome occurs, the illness condition will usually have rapid progression and poor prognosis (no more than 10% can survive for 3 years).

4. Uremia (renal failure) stage. The renal function will experience progressive decline and more than half will have azotemia and serious cases can die of uremia. In some conditions, the renal tubules and renal interstitial can be affected and patients can have diuresis or even diabetes insipidus. Some can even have renal glycosuria, renal tubular acidosis, hypokalaemia and electrolyte disorders.