Clinical And Pathological Features Of Elderly Kidney Disease

According to the recommendations of the World Health Organization (WHO), "elderly people" are defined as people aged ≥60 years in Asia-Pacific and developing countries, and ≥65 years old in other regions. A country, more than 7% of the population is over 65 years old or more than 10% of the population over 60 years old is an aging society. With the improvement of my country's living standards and the gradual improvement of medical care, the life expectancy of Chinese people has been significantly prolonged, and the elderly population has increased year by year. According to the 5th national census in 1999, 10.2% of those aged ≥ 60 and 6.96% of those aged ≥ 65 Therefore, our country has entered an aging society.

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With the increase of age, the structure and function of human tissues and organs undergo certain changes. Therefore, senile diseases, including kidney disease, have received attention.

Due to the different degrees of aging of various systems and organs, the aging of the cardiovascular system, the aging of the immune system, the aging of the urinary system, and the high incidence of tumors are closely related to elderly kidney diseases. In short, the etiology, pathogenesis, and distribution of disease types of elderly kidney diseases have their characteristics. Common kidney diseases in the elderly are as follows.

Asymptomatic proteinuria and hematuria

ischemic kidney injury

Glomerulosclerosis and ischemic shrinkage can be seen in the renal tissue of the patient, and ischemic changes can also be seen in the peripheral renal tubules and interstitium. Sometimes the damaged area can be seen in a band-like concentrated distribution, which is due to the larger vascular lesions upstream of the site. Caused. Patients can have ischemic kidney damage due to atherosclerosis with or without hypertension.

obesity-related nephropathy

A considerable number of elderly people have excess body mass index, which can lead to a small amount of proteinuria due to hemodynamic changes. Pathological manifestations are glomerular hypertrophy and renal stenosis.

Macroalbuminuria and Nephrotic Syndrome (NS)

Membranous Nephropathy (MN)

MN accounts for 25%-54% of elderly NS patients, and primary membranous nephropathy (pMN) accounts for 76.3%. Although the clinical and pathological manifestations of elderly MN are the same as those of other middle-aged groups, special attention should be paid to its relationship with tumors. The elderly are a high-risk group for various tumors, and reports of elderly MN combined with or secondary to tumors are common (that is, the antigens that cause MN are derived from tumor antigens). In addition to PSA of clear renal cell carcinoma, CD10 of clear renal cell carcinoma, etc.), there are no specific markers for many other tumors, and it is difficult to accurately solve this problem by pathological examination of renal biopsy. Therefore, the so-called pMN still contains a certain degree of secondary membranous nephropathy (see). In addition to various tumors, elderly sMN can also be caused by hepatitis B or C virus and drugs.

Minimal Change Nephropathy (MCD)

The incidence of MCD has two peaks in children and the elderly. MCD accounts for 15% to 20% of elderly NS patients, and the pathological manifestations are the same as those of children with MCD, and sometimes it can be associated with tumors.

Focal segmental glomerulosclerosis (FSGS) FSGS accounts for 7% to 10% of elderly NS patients, and special attention should be paid to removing the factors of ischemic kidney injury in the pathological diagnosis.

Diabetic Nephropathy (DN)

The elderly are a high-incidence age of diabetes, and type 2 diabetes is the main cause of elderly DN. It is not difficult to make a clear diagnosis with a complete medical history and pathological examination of light microscopy, immunofluorescence, and electron microscopy.

Particular protein or paraproteinemia nephropathy

Due to B cell hyperplasia or tumor, excessive light chain protein or other special proteins appear in the body and then deposit in the glomerulus's mesangial area and basement membrane, resulting in massive proteinuria or NS relatively common in elderly kidney disease. Including renal amyloidosis, light chain deposition disease, macroglobulinemia nephropathy, fibronectin glomerulopathy, etc., the common pathological features are nodular sclerosis in the mesangial region, thickening of the basement membrane, and auxiliary It is not difficult to diagnose by immunofluorescence and electron microscopy.

Acute Kidney Injury (AKI) and Acute Renal Failure (ARF)

Crescentic glomerulonephritis can lead to the destruction of glomerular capillary loops for various reasons, resulting in glomerular capillary loop necrosis and crescent formation, affecting renal function and even renal failure. Anti-neutrophil cytoplasmic antibody (ANCA)-associated polyangiitis is a common cause of type III crescentic glomerulonephritis, and ANCA-associated polyangiitis is more common in the elderly, and about 40% of people over 60 years old. %. The diagnosis should be based on clinical manifestations, serum ANCA titers, and pathological examinations. Type I crescentic glomerulonephritis and IgA nephropathy caused by anti-basement membrane antibodies, and type II crescentic glomerulonephritis caused by type IV lupus nephritis are also seen in elderly patients, but less frequently.

acute tubulointerstitial nephropathy

Acute severe tubular injury and acute tubular necrosis both show AKI or ARF, so they belong to the category of acute tubular disease. The pathological morphology of the former is extensive shedding of the bristle borders of renal tubular epithelial cells, dilation of the lumen, edema of the renal interstitium, and the shed and disintegrated cell debris is washed into the deep tubules by the urine; dissolved cell debris. Acute tubular injury and necrosis can be caused by acute renal ischemia and nephrotoxic substances and are common causes of AKI in the elderly.

Acute Interstitial Nephritis Acute allergic interstitial nephritis is often caused by drugs (such as non-steroidal anti-inflammatory drugs, antibiotics, Chinese herbal medicine, etc.), and it is easy to see the infiltration of eosinophils in the interstitium. Idiopathic acute interstitial nephritis or tubulointerstitial nephritis-uveitis (TINU) syndrome can also be seen in elderly patients. Sjögren's syndrome can also lead to interstitial nephritis.

acute cast nephropathy

Massive red blood cell casts caused by hematuria (common in IgA nephropathy), cast nephropathy caused by myeloma, myoglobin casts caused by muscle necrolysis, hemoglobin casts caused by hemolysis, bile casts caused by direct bilirubin, Uric acid casts caused by oncolytic syndrome can severely damage renal tubules, leading to AKI or ARF.

acute renal vascular disease or disease

acute renal ischemia

The elderly generally suffer from atherosclerosis or other vascular diseases. Therefore, the renal artery or its branches are prone to thrombosis. It is difficult to establish collateral circulation, which will inevitably lead to acute renal ischemia and even renal infarction. The patient presented with renal pain, hematuria, and ARF.

cholesterol embolism

In recent years, to improve blood circulation, arterial catheter interventional therapy is often performed. During the operation, atherosclerotic plaques can be touched to make them fall off, and embolized in the branches of renal arteries with the blood flow, causing spasms of the renal arterial system and leading to ARF. . At the same time, patients often have toe pain, toe skin purple phenomenon, known as purple toe syndrome.

thrombotic microangiopathy

It includes a large group of diseases. The elderly people who cause ARF are more common in malignant hypertension, and they are often combined with IgA nephropathy and occasionally in systemic sclerosis.

Large and medium vasculitis of the kidney

Polyarteritis nodosa can lead to ARF in the elderly, and Takayasu arteritis and other Takayasu arteritis occasionally involve the renal arteries.

Chronic renal failure (CRF)

The chronic phase of many of the above-mentioned elderly kidney diseases can develop into CRF. geriatric nephritic syndrome

The proportion of acute intracapillary proliferative glomerulonephritis in senile nephritic syndrome is relatively small, but various types of IgA nephropathy are. Other secondary renal diseases, such as lupus nephritis, are not much different from the clinical and pathological manifestations of young adults.

In conclusion, when diagnosing elderly kidney disease, not only the clinical manifestations and pathological changes should be paid attention to, but also the general state of the elderly, changes in the immune system, and age-related characteristics of the kidneys.

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