hypertensive nephropathy



Overview of Hypertensive Nephropathy

Definition

Hypertensive nephropathy is a kidney disease caused by long-term primary hypertension leading to atherosclerosis of small renal arteries.

The diagnostic criteria for hypertension have been changing over time. The latest Chinese Clinical Practice Guidelines for Hypertension released in 2022 recommend the diagnostic criterion of a systolic blood pressure ≥130 mmHg and/or a diastolic blood pressure ≥80 mmHg measured three times on non-same days without the use of antihypertensive medication as hypertension.

Grading

Classification according to systolic and/or diastolic blood pressure values

It can be categorized into Hypertension 1 and Hypertension 2. The details are shown in the table below [1].

and

<80

Grade 1 hypertension (mild) 130 to 139 and/or 80 to 89

Grade 1 hypertension (mild)

130～139

and/or

80～89

Grade 2 hypertension ≥140 and/or greater than or equal to 90

Grade 2 hypertension

≥140

and/or

greater than or equal to 90

Morbidity

This disease is one of the complications of primary hypertension.

It occurs in people who have had primary hypertension for a long time and whose blood pressure is chronically high and poorly controlled.

Causes

Causes

The main cause is essential hypertension.

Elevated blood pressure will lead to increased pressure on the glomeruli, long-term hypertension will lead to glomerular fibrosis and atrophy, renal artery sclerosis, renal parenchyma ischemia, necrosis, and in severe cases, renal failure can occur.

Malignant hypertension can cause acute renal failure in a short period of time.

Symptoms

Main Symptoms

Elevated blood pressure

Blood pressure may rise suddenly or gradually.

Dizziness, headache, palpitation, chest tightness and other symptoms may accompany due to elevated blood pressure.

Urine changes

Increased urine output: Early stage of the disease may show increased urine output, i.e., under the condition of unchanged water intake and sweating, the amount of urine per day is significantly higher than before; in some cases, it may be manifested as increased urine output at night.

Decrease in urine output: when the disease is more serious, there may be a decrease in urine output, i.e., under the condition that the amount of drinking water and sweating remain unchanged, the amount of urine per day is significantly less than before or almost none.

Foamy urine: increased foaminess in urine can occur in severe cases due to proteinuria.

Edema

Edema may appear in the eyelids first, and in severe cases, the whole body may be edematous. Pressing on the edematous area may cause depression.

Other symptoms

Hypertensive nephropathy is the result of the development of high blood pressure to a certain extent, at this time, other organs of the body may also be damaged by high blood pressure, and the corresponding symptoms appear.

For example, cerebrovascular damage can cause cerebrovascular disease, headache, vomiting, slurred speech, hemiplegia, facial paralysis, impaired consciousness and other symptoms.

If the coronary artery is damaged, it can cause coronary heart disease or heart failure, with symptoms such as palpitations, chest tightness, chest pain, and dyspnea.

Damage to the blood vessels of the eyes may cause hypertensive retinopathy, with symptoms such as blurred vision.

If the aorta is damaged, it can cause aortic coarctation, with symptoms such as severe chest and back pain, and large difference in blood pressure values of upper limbs on both sides.

Complications

Acute heart failure: manifested by sudden onset of severe shortness of breath, often accompanied by blue lips, profuse sweating, coughing up pink foamy sputum, sedentary respiration, elevated blood pressure, rapid pulse rate, etc.

Consultation

Department of Medicine

Nephrology

Hypertensive patients with sudden increase in blood pressure, edema, oliguria, foamy urine, etc. are advised to consult the Nephrology Department.

Preparation for medical treatment

Consultation: Registration, Preparation of documents, Frequently Asked Questions

Tips for Consultation

Hypertensive patients should pay attention to monitoring the changes of blood pressure and have regular physical examination to check the lesions of relevant organs in the body.

Preparation List

Symptom list

Pay special attention to the time of onset of symptoms, special manifestations, etc.

What are the changes in the urine? Do you have symptoms of hematuria or foamy urine?

Have you measured your own blood pressure recently? How is your blood pressure controlled?

Has there been a change in weight? Is there any edema?

Medical History Checklist

Is there a family history of high blood pressure?

Any drug or food allergies?

Any other medical conditions?

Checklist

Test results for the last 6 months, which can be brought to the doctor’s office

Routine blood tests

Blood Biochemistry

Urinalysis

Renal Function Test

Abdominal Ultrasound

Abdominal CT

Renal puncture test

Medication List

Medication used in the last 3 months, if available, bring the box or package with you to the doctor’s office

Diuretics: hydrochlorothiazide, furosemide, spironolactone

Beta-blockers: propranolol, nadolol

Angiotensin-converting enzyme inhibitors: captopril, enalapril, benazepril

Calcium channel blockers: verapamil, diltiazem

Angiotensinase II receptor antagonists: chlorosartan, valsartan, irbesartan

Sympathetic depressants: colistin, reserpine

Diagnosis

Diagnosis is based on

Medical history

A clear history of primary hypertension.

Clinical manifestations

Symptoms

Persistent elevated blood pressure, increased or decreased urine output, foam in the urine, and edema.

Physical signs

Depression may be seen by pressing on the edematous area.

Laboratory Tests

Urine routine

Urine specific gravity, urine protein, etc. can be checked.

It can clarify the severity of the disease and is one of the necessary tests to confirm the diagnosis of the disease.

Precautions: The test should be done in the middle part of the urine, i.e., a part of the urine should be discharged first, and then the urine should be left in the urine cup, stop urinating when it is not completely discharged, and drain the remaining urine after removing the urine cup.

Blood biochemistry

Checks kidney function, electrolytes, and albumin.

There may be an increase in the concentration of substances related to kidney function such as creatinine and urea nitrogen, an increase in electrolytes such as potassium ions, and a decrease in albumin.

Precautions: Fasting must be maintained before the outpatient examination, i.e., fasting for at least 6 hours and water fasting for at least 4 hours; no fasting and water fasting is required for the emergency examination.

Estimation of glomerular filtration rate

Glomerular filtration rate can change and is one of the tests necessary to confirm the diagnosis of the disease.

24-hour urine protein quantitative test

Measurement of the total amount of urine protein over a 24-hour period.

In hypertensive nephropathy, 24-hour urine protein is elevated.

Precautions: Urine from 24 consecutive hours is collected into a clean container and the total volume is recorded. Use a urinary catheter to collect a certain amount of mixed 24-hour urine during the test and send it for testing promptly.

Adrenocorticotropic Hormone Test

Detects levels of hormones such as aldosterone.

It can rule out diseases such as adrenal endocrine-related hypertension.

Imaging

Renal ultrasound, renal vascular ultrasound

Renal ultrasound can understand the morphology and structure of the kidneys; renal vascular ultrasound can understand the blood flow of renal arteries and renal veins.

Enlargement or atrophy of the kidney may occur, and can also be used to identify other diseases.

Precautions

Expose the lower back and abdomen as requested by the doctor before the examination.

A coupling agent will be applied to the skin surface of the lower back and abdomen during the examination. Generally, the coupling agent is not damaging to the skin.

Maintain a fixed position during the examination as requested by the doctor and avoid moving around.

The coupling agent can be wiped off with tissue paper after the examination.

Abdominal CT

To understand the changes in the morphology and structure of abdominal organs such as kidneys.

Used to identify other diseases.

Precautions

Remove jewelry or metal objects, such as belts, from the examination area and remove pants made of metal before the examination.

Contrast dye may be injected. If you are allergic to contrast dye, please inform your doctor in advance.

Pathologic examination

Kidney tissue is taken by renal puncture to find out the pathological changes in the kidney tissue.

The examination is consistent with the pathologic changes of hypertensive nephropathy and is one of the tests necessary to confirm the diagnosis of this disease, and can also be used to identify other diseases.

Precautions

The skin should be kept clean before puncture.

Anesthesia medication will be used during the procedure, and there is mostly no obvious pain.

Keep the puncture site clean after the procedure to avoid infection.

If there is redness, swelling, severe pain or heavy bleeding at the puncture site, consult a doctor promptly.

Differential diagnosis

Hypertension combined with primary kidney disease

Similarities: elevated blood pressure, increased or decreased urine output, foam in urine, etc.

Differences: The etiology of primary nephropathy is unknown, and it may be related to abnormal immune function, with lesions occurring in structures such as basement membranes and tethered membranes. It can be differentiated by histopathologic examination, etc.

Renal hypertension

Similarities: elevated blood pressure, increased or decreased urine output, foam in the urine, etc.

Differences: Renal hypertension may have a history of kidney disease, mostly without a clear history of hypertension. Elevated blood pressure correlates with the onset and progression of kidney disease, and blood pressure will return to normal while the kidney disease is in remission or cured. It can be differentiated by histopathologic examination.

Treatment

Medication

Oral medication is the main treatment for hypertensive nephropathy. The goal of blood pressure control is less than 130/80 mmHg. If the effect of drugs in lowering blood pressure is not satisfactory, it can be combined with hemodialysis treatment.

Generally, an angiotensin-converting enzyme inhibitor (ACEI) or an angiotensin II receptor antagonist (ARB) can be used alone or in combination with other drugs.

Angiotensin-converting enzyme inhibitors (ACEI)

They lower blood pressure by inhibiting angiotensin-converting enzyme and reducing the production of angiotensin II. While lowering blood pressure, they can also reduce urinary protein and delay the progression of nephropathy.

Commonly used captopril, enalapril, benazepril, fosinopril, perindopril, lynopril and so on.

Precautions

Adverse reactions include pharyngeal itching, irritating dry cough, dysgeusia, and edema.

Blood creatinine and potassium levels must be monitored regularly.

Contraindicated in hyperkalemia, pregnant women, bilateral renal artery stenosis.

Angiotensin II receptor antagonist (ARB)

By blocking the angiotensin II receptor subtype, inhibit the corresponding vasoconstriction, so as to achieve the effect of lowering blood pressure. While lowering blood pressure, they can also reduce urinary protein and slow down the progression of nephropathy.

Commonly used chlorosartan, valsartan, irbesartan, timosartan, candesartan and so on.

Precautions

Adverse reactions are rare and may include headache, dizziness, cough, diarrhea, and fatigue.

Regular monitoring of blood creatinine and potassium levels is required.

Contraindicated in hyperkalemia, pregnant women, bilateral renal artery stenosis.

Calcium channel blocking drugs (CCB)

By blocking the entry of extracellular calcium ions into vascular smooth muscle cells, they reduce vasoconstriction and exert antihypertensive effects.

Commonly used dihydropyridines (e.g. amlodipine, nifedipine, felodipine, lacidipine), non-dihydropyridines (e.g. verapamil, diltiazem) and so on.

Precautions

Adverse reactions include increased heart rate, facial flushing, headache, and lower extremity edema.

Avoid non-dihydropyridine CCBs in people with heart failure and heart block.

Diuretics

By promoting the discharge of sodium ions with urine, reducing the volume of extracellular fluid and lowering peripheral vascular resistance, so as to achieve the purpose of lowering blood pressure.

Thiazide diuretics (e.g., hydrochlorothiazide) are commonly used when the glomerular filtration rate exceeds 30 ml/(min – 1.73m2); labeled diuretics (e.g., furosemide) are commonly used when the glomerular filtration rate is less than 30 ml/(min – 1.73m2).

Adverse effects include affecting the metabolism of lipids, blood glucose, blood uric acid, and electrolytes, causing hypokalemia and hyponatremia.

Beta-blockers

They exert antihypertensive effects through various mechanisms such as decreasing myocardial contractility and slowing down heart rate.

Commonly used metoprolol, atenolol, bisoprolol, carvedilol, propranolol and so on.

Precautions

Adverse effects include bradycardia, fatigue, chills in the extremities, etc.

Contraindicated: severe bradycardia, heart block, asthma, chronic obstructive pulmonary disease, peripheral vascular disease.

Use with caution: insulin-dependent diabetes mellitus and hyperlipidemia.

Sympathetic Nerve Inhibitors

Achieve antihypertensive effect by inhibiting myocardial contraction and vasoconstriction, with cardioprotective and renal effects.

Commonly used sympathetic nerve terminal blockers (such as rifampicin), central sympathetic inhibitors (such as colistin).

Other drugs

Direct vasodilators: achieve the effect of lowering blood pressure by directly relaxing smooth muscle and dilating peripheral blood vessels. Commonly used drugs include hydralazine and sodium nitroprusside.

α1 receptor blocking drugs: through the diastolic blood vessels, reduce the pressure of peripheral blood vessels, to achieve the effect of lowering blood pressure. Commonly used drugs include prazosin, terazosin, doxazosin and so on.

Indapamide: has diuretic and calcium channel blocking effects. It can be used alone or in combination with other antihypertensive drugs.

Renin inhibitors: can exert antihypertensive effects by regulating the renin-angiotensin system, such as aliskiren.

Hemodialysis

Hemodialysis, abbreviated as hemodialysis, is a treatment method in which the body’s blood is drained outside the body, and metabolic wastes, excess fluid, and excess electrolytes in the blood are transferred to the outside of the body through an instrument, and then the filtered blood is infused back into the body. It can improve the disturbance of water, electrolyte, acid-base balance.

When end-stage renal disease occurs in hypertensive nephropathy, hemodialysis combined with drug antihypertensive treatment may be taken.

Precautions

Before dialysis, patients or family members should fully communicate with doctors to understand the purpose and risks of dialysis.

A vascular access called an autologous arteriovenous endovascular fistula will be surgically created in the wrist before dialysis. After the surgery, you can promote the recovery of the surgical site and improve the function of the endovascular fistula by elevating the hand about 30° and functional exercises.

Regular treatments are given at the times required by your doctor.

Hemodialysis must be performed in a hospital for a long period of time and should be preceded by bowel movement and urination.

Anticoagulant medication will be used continuously during each dialysis session and blood must be drawn several times to test the coagulation function.

Avoid squeezing and pulling the tubing during the dialysis process; inform the doctor promptly if there is any discomfort such as dizziness and fatigue.

After hemodialysis, apply pressure to the fistula site for at least 10 minutes, or use elastic bandage to prevent bleeding.

Pay attention to the protection of the internal fistula site, avoid wearing a watch, lifting heavy objects, pressure, bumping, hot and cold stimulation, blood extraction and other behaviors. If there is bleeding, local pain, local redness and swelling, etc., consult the doctor promptly.

Prognosis

Cure

Hypertensive nephropathy is not curable, but it can be treated in time to slow down the progress of the disease, relieve the symptoms and improve the quality of life.

Harmfulness

Hypertensive nephropathy can cause edema, increased blood pressure, decreased urine output and other symptoms, which can reduce the quality of life.

If not treated in time, it may affect life expectancy.

It can cause complications such as hyperkalemia and sudden death in severe cases.

Daily

Daily management

Dietary management

Low salt diet

Daily salt intake should be less than 5 grams (equivalent to about 25 ml of soy sauce).

Avoid pickled food, such as pickles, fermented bean curd, dashi, bacon, preserved meat and red sausage.

Reduce intake of fast food, such as instant noodles and instant rice.

Ensure balanced nutrition

Limit the total calories and the diet should be eight-minute full.

Ensure sufficient unsaturated fat, vitamins, minerals and dietary fiber.

Meat is preferred to poultry and fish, about one poker box-sized amount per day; or choose the type of protein food according to the doctor’s requirements to control the intake.

One palmful of nuts per day.

Choose fresh low-sugar fruits, such as kiwi, strawberries, pears, grapefruit, etc., one to two per day.

Fresh vegetables 400~500 grams (raw weight) per day.

Reduce the intake of carbohydrates appropriately, and choose cereals and potatoes instead of refined rice and noodles.

Control the amount of cooking oil, which should be less than 25 grams per day (about 2.5 white porcelain soup spoons)

Ensure water intake as directed by your doctor

Avoid other inappropriate diets

Avoid stimulating beverages such as strong tea and coffee.

Avoid foods high in saturated fat such as fatty meats and fried foods.

Abstain from alcohol.

Life Management

Avoid exertion.

Ensure adequate sleep and avoid staying up late.

Try to avoid heavy physical labor, such as lifting heavy objects, long or prolonged riding or driving. Or follow your doctor’s instructions to choose the appropriate intensity of labor.

Quit smoking and stay away from second-hand smoke.

Exercise management

Exercise for at least 150 minutes per week, with each exercise session lasting at least 30 minutes. Exercise programs may include walking, cycling, jogging, tai chi, swimming and other activities. Or follow the doctor’s instruction to plan the time and choose the exercise program.

Exercise should be gradual and avoid excessive exercise.

If you feel uncomfortable during exercise, you should stop exercising immediately.

Emotional management

Avoid bad emotions such as tension, anxiety, anger and depression.

They can be relieved by chatting with friends and relatives, listening to soft music, reading books and watching soothing TV programs.

In severe cases, you can go to a formal psychological counseling agency for psychological counseling and treatment.

Avoid environmental stimuli

Avoid cold and heat.

Keep warm when going out in winter.

In summer, pay attention to prevent heatstroke, and the temperature of indoor air-conditioning should not be too low.

Avoid prolonged exposure to excessive cold or heat.

Weight and Waistline Management

Keep your body mass index (BMI) at 18 to 23.9.

Do not exceed 90 cm waist circumference for men and 85 cm for women.

Condition monitoring

Monitoring blood pressure

You can measure your own blood pressure at home using a sphygmomanometer, choosing an upper-arm electronic sphygmomanometer from a regular manufacturer.

Try to take measurements at the same time period and in a quiet state, such as sitting measurement after urinating at 7:00 a.m. every day.

Avoid drinking coffee, alcoholic beverages, strong tea, etc. and empty your bladder (urinate) before measurement.

Avoid strenuous activities before measurement. If there is activity, rest for at least 5 minutes before taking the measurement.

Try to expose as much skin as possible on the upper arm during measurement. If the sleeve is rolled up too tightly, remove the clothing on the side of the measurement.

The lower side of the cuff should be 2 horizontal fingers (about 2.5 cm) from the middle of the elbow socket during measurement, and the cuff should be elasticized to accommodate 1 finger.

Avoid moving your body, clenching your fists, talking, watching TV, etc. during the measurement.

The interval between measurements should be 1 to 2 minutes, and the cuff should be untied and relaxed between measurements.

Avoid continuous measurements.

Monitoring of in- and outflow

Record the amount of fluid that enters the body during diet, medication, and infusion, as well as the amount of fluid excreted during bowel movements and sweating.

Follow-up

Follow up with your doctor at regular intervals for biochemistry and heart ultrasound.

If your symptoms do not improve or worsen, or if new symptoms appear, you should consult your doctor promptly.

Prevention

Actively treat the disease

Follow your doctor’s instructions for treating high blood pressure, take medication on time, monitor your blood pressure, and avoid changing or stopping treatment on your own.

Improve diet

Choose a low-salt diet and avoid stimulating foods and drinks.