Sickle cell nephropathy

Introduction to sickle cell nephropathy Kidney damage caused by sickle cell disease is called sicklecellnephropathy. Sickle cell disease is a hemoglobinopathy caused by abnormal hemoglobin. It is most common with hemolytic anemia, accompanied by low Specific gravity and polyuria suggest that the patient has abnormal renal tubular function. basic knowledge Sickness ratio: 0.05% Susceptible people: no special people Mode of infection: non-infectious Complications: osteomyelitis chronic renal failure acute renal failure

The cause of sickle cell nephropathy

(1) Causes of the disease

Sickle cell disease is caused by the genetic inheritance of the abnormal -globin chain subunit of hemoglobin. The patient obtains two identical abnormal hemoglobin genes, homozygous, from both parents, and the red blood cells lack normal hemoglobin (HbA) and are abnormal. Replaced by hemoglobin (HbS), called sickle cell anemia or sickle cell disease, patients get an abnormal hemoglobin gene from the parent's side, that is, heterozygous, the red blood cells contain normal and abnormal hemoglobin, but the normal accounted for 50 More than % is called a sicle cell trait.

(two) pathogenesis

Sickle cell disease is caused by the genetic inheritance of the abnormal -globin chain subunit of hemoglobin. The patient obtains two identical abnormal hemoglobin genes, homozygous, from both parents, and the red blood cells lack normal hemoglobin (HbA) and are abnormal. Replaced by hemoglobin (HbS), called sickle cell anemia or sickle cell disease, patients get an abnormal hemoglobin gene from the parent's side, that is, heterozygous, the red blood cells contain normal and abnormal hemoglobin, but the normal accounted for 50% More than %, called sicle cell trait, the appearance of sickle-shaped red blood cells is caused by the polymerization of abnormal hemoglobin molecules, which can cause two main phenomena:

1. Chronic compensatory hemolytic anemia.

2. Vasooclusive crises cause pain and tissue damage.

When the glutamic acid at the 6th position of the -chain of abnormal hemoglobin is replaced by proline, the morphological change occurs under hypoxic conditions, and the abnormal hemoglobin molecules are polymerized into a polymer. The red blood cells change from a disc shape to a sickle shape, and the percentage of abnormal hemoglobin increases. Sorghum becomes more severe, and red blood cells become heavier in certain causes such as cell dehydration and acidosis.

Red blood cells repeatedly metamorphose, resulting in damage to the cell membrane, potassium ions and water leakage in the cells, which will increase the dehydration of red blood cells. The accumulation of intracellular calcium ions can make the sickle cells stiff and irreversible, and the lifespan of these red blood cells is shortened (about 10 days). It is easily destroyed by the reticuloendothelial system, leading to hemolytic anemia.

Because the sickle-shaped red blood cells are not easily deformed, the blood flow stagnates when passing through the microcirculation, forming a vicious viscous sickle cycle, and finally blocking the microcirculation, leading to ischemia and infarction, pain and tissue damage. The above-mentioned lesions occur in the kidneys and cause significant damage to the renal blood vessels, renal tubules and glomeruli.

Sickle cell nephropathy prevention

Although there is no special treatment for this disease, for example, it can help patients to avoid the cause of mutating, strengthen self-care, pay attention to keep warm, avoid fatigue, etc. It is beneficial to prevent the occurrence of acute crisis and improve the prognosis. Western medicine uses vasodilators, painkillers, blood transfusions, antibiotics and oxygen, while Chinese medicine can use Astragalus, Salvia, Chuanxiong for long-term use or according to the above-mentioned syndrome differentiation, it will be more effective.

Sickle cell nephropathy complications Complications osteomyelitis chronic renal failure acute renal failure

Two important complications and disabling diseases of the disease are osteonecrosis and osteomyelitis. The main complication of renal damage in patients is acute and chronic renal failure.

Symptoms of sickle cell nephropathy Common symptoms Kidney damage, severe pain, severe pain, polyuria, chronic renal failure, jaundice, urinary microcirculatory disorder, hyperuricemia, hematuria

1. Clinical features of sickle cell disease

(1) homozygous sickle cell disease: there are varying degrees of hemolytic anemia, mild jaundice, vascular occlusion crisis is its outstanding performance, often severe pain in the trunk and limbs, including internal organs, bones, joints and muscle pain Etc., especially in the metacarpal, epiphyseal and finger (toe) bone infarction is more common, infection, dehydration, hypoxia and acidosis are the incentives, visceral and cerebrovascular infarction have corresponding symptoms and signs.

(2) heterozygous sickle cell disease: usually asymptomatic, does not occur hemolytic anemia, it is also known as sickle cell tendency, only microcirculatory disorder in severe hypoxia, mainly in the straight blood vessels of the renal medulla, Because there is significant hypertonicity in this place, the red blood cells are easy to dehydrate, combined with the physiological characteristics of low oxygen tension and low pH, leading to red blood cell transmutation, renal medullary blood stasis, and even vascular occlusion, severe renal nipples can occur Necrosis.

2. Clinical features of sickle cell nephropathy

Most patients with sickle cell anemia or sickle cell tend to have no clinical manifestations of kidney disease, but a small number of patients do have renal papillary necrosis and urinary concentrating dysfunction.

(1) hematuria: homozygous or heterozygous type can occur hematuria, hematuria is the most common manifestation of renal damage, can be gross hematuria, but microscopic hematuria, may be minimal necrosis of renal medulla and renal papilla Caused by glomerular hematuria.

(2) nephrotic syndrome: sickle cell disease can occur typical nephrotic syndrome, pathologically can be minimal lesion type, mesangial proliferative type, membrane proliferative type and focal glomerular sclerosis type, mesangial area And epithelial cells can have iron deposits.

(3) renal tubular insufficiency: in patients with sickle cell anemia, renal tubular lesions are more common, early renal dysfunction can occur, followed by decreased concentration and dilution ability, isotonic urine, early disease Reversible, late due to chronic ischemia, irreversible damage to the renal medulla, permanent polyuria, nocturia and other urinary concentrating dysfunction, distal renal tubular acidosis, mostly incomplete.

(4) Hyperuricemia: The red blood cell metabolism of this disease is 6-8 times higher than that of normal people, and the production of uric acid is excessive, but the clearance rate is increased, so gouty arthritis does not occur.

(5) Renal failure: This disease can cause acute renal failure due to renal vascular occlusion and acute intravascular hemolysis. Due to glomerular lesions and multiple metamorphosis, 18% of patients can develop chronic renal failure. The end of the period.

Examination of sickle cell nephropathy

Blood test

There are varying degrees of hemolytic anemia and mild jaundice. The red blood cells lack normal hemoglobin (HbA) and are replaced by abnormal hemoglobin (HbS). Hemoglobin electrophoresis shows a large amount of HbS, and the sickle cell formation test is positive.

2. Urine check

Visible hematuria, proteinuria, hypotonic polyuria; this disease regardless of homozygous or heterozygous type can occur hematuria, can be gross hematuria, but microscopic hematuria, may be the renal medulla and kidney nipple tiny Due to necrosis, it can also be glomerular hematuria. Sickle cell disease can develop typical nephrotic syndrome. At this time, laboratory changes of nephrotic syndrome can occur.

Renal biopsy suggests glomerular enlargement and congestion in patients with sickle cell anemia, sickle cells filled the lumen, mesangial cells proliferated to varying degrees, and mild to moderate vessels were seen due to thickening of the glomerular capillary basement membrane. Wall hypertrophy, in patients with nephrotic syndrome, increased glomerular lobes, suggesting the presence of glomerular capillary vasculitis, iron deposits in the epithelial and endothelial cells, segmental glomerular sclerosis and membranous Nephropathy can also be seen, electron microscopy suggests that 25nm particles are concentrated in the intercapillary and epithelial cells, common mesangial cell proliferation and peripheral mesangial metastasis, immunofluorescence is mostly negative, some patients can see IgG and C3 not Rules are deposited around the capillaries, most of which are nephrotic syndrome, membranous or mesenteric capillary glomerulonephritis.

Diagnosis and differentiation of sickle cell nephropathy

The main diagnosis basis:

1. Anemia Hb is usually 70 ~ 80g / L, is hemolytic anemia, accompanied by trunk or limb paroxysmal pain and should be suspected of this disease, reticulocytes often reach 10%.

2. Red blood cell mutagenesis test positively mix the patient's blood with sodium metabisulfite solution, deoxygenation of blood induces red blood cell transmutation, microscopic examination of sickle-shaped red blood cells, or hemoglobin dissolution test, adding the above solution to phosphate solution, normal hemoglobin No precipitation occurred in the dissolution, abnormal hemoglobin solubility was low, and turbid precipitation occurred.

3. Abnormal hemoglobin (HbS) occurs in hemoglobin electrophoresis.

4. Hemoglobin electrophoresis showed a large amount of HbS, and the sickle cell formation test positively confirmed the tendency of sickle cells. The sickle cell disease was accompanied by hematuria, proteinuria, hypotonic polyuria, nephrotic syndrome, pyelonephritis, renal tubules. The disease can be diagnosed by dysfunction and renal damage such as acute and chronic renal failure.

Differential diagnosis

Care should be taken to distinguish from other types of anemia and kidney disease.

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