HYPERTENSION AND THE KIDNEY

Hypertension can be the cause or the result of renal disease (renal hyper-tension), and it is often difficult to differentiate between the two on clinical grounds. Investigations, as described on page 482, should be performed on all patients, although renal imaging is usually unnecessary.

Essential hypertension

Hypertension leads to characteristic histological changes in the renal vessels and intrarenal vasculature over time. These include intimal thickening with reduplication of the elastic lamina, reduction in kidney size, and an increase in the proportion of sclerotic glomeruli. The changes are usually accompanied by some deterioration in renal function, which is much more common in black Africans.

Accelerated or malignant-phase hypertension is marked by the develop-ment of fibrinoid necrosis in afferent glomerular arterioles and fibrin deposi-tion in arteriolar walls. A rapid rise in blood pressure may trigger these arteriolar lesions, and a vicious circle is then established whereby fibrin deposition leads to renal damage, increased renin release and a further increase in blood pressure. There is progressive uraemia and, if untreated, fewer than 10% of patients survive 10 years.

Treatment of hypertension is described on page 483. The outlook is good if treatment is started before renal impairment has occurred.

Renal hypertension

Bilateral renal disease

Hypertension commonly complicates bilateral renal disease, such as in chronic glomerulonephritis, reflux nephropathy or analgesic nephropathy. Two main mechanisms are responsible:

■ Activation of the renin-angiotensin-aldosterone system

■ Retention of salt and water, leading to an increase in blood volume and hence blood pressure.

Good control of blood pressure will prevent further deterioration in renal function, with ACE inhibitors or angiotensin II blockers being the drugs of choice. These drugs confer an additional renoprotective effect for a given degree of blood pressure control when compared with other hypotensive drugs.

Renovascular disease

Narrowing of the renal arteries (renal artery stenosis, RAS) is usually due to atheroma and classically occurs in patients with evidence of generalized atheroma, e.g. peripheral vascular disease and coronary artery disease. In younger patients, particularly women, it is more commonly due to fibromus-cular hyperplasia. Renal perfusion pressure is reduced and renal ischaemia results in a reduction in the pressure in afferent glomerular arterioles. The mechanism of hypertension with RAS is illustrated in Fig. 9.5.

Imaging for RAS is indicated in the following circumstances:

■ Evidence of atheromatous vascular disease in patients with hypertension or progressive CKD

The mechanism of hypertension in unilateral renal artery stenosis

Fig. 9.5 The mechanism of hypertension in unilateral renal artery stenosis. (Adapted from Davidson 1991 Principles and Practice of Medicine. Churchill Livingstone, Edinburgh.)

■ A rise in the serum creatinine by more than 30% after introduction of an ACE inhibitor or angiotensin II receptor antagonist (an increase of 30% is acceptable and reflects reduction of glomerular perfusion)

■ Abdominal bruits in a patient with hypertension or CKD

■ Recurrent flash pulmonary oedema without cardiopulmonary disease

■ Renal asymmetry of >1.5 cm in length on imaging.

Options for renal artery imaging

The gold standard for diagnosing renal artery stenosis is renal arteriography. This requires cannulation of the femoral vein and less invasive imaging with MR or CT angiography or Doppler ultrasonography is often used in the first instance. The choice of test is based on institutional expertise and patient factors, e.g. CT with intravenous contrast is avoided in patients with poor renal function. If non-invasive imaging is inconclusive and clinical suspicion is high then conventional arteriography is necessary.

Management

Standard medical therapy for atherosclerotic vascular disease is indicated in all patients and includes lifestyle modification (increased exercise and smoking cessation), statins, antiplatelet therapy (p. 242) and antihyperten-sives for effective blood pressure control. Transluminal angioplasty (to dilate the stenotic region) and stent placement is used in patients with fibromus-cular hyperplasia but does not offer any additional benefit (to medical treat-ment) in most patients with atheromatous stenosis.

Ebook Essentials of Kumar and Clark's Clinical Medicine, 5e

1. Ethics and communication

Ethics and communication

2. Infectious diseases

Infectious diseases

3. Gastroenterology and nutrition

Gastroenterology and nutrition

4. Liver, biliary tract and pancreatic disease

Liver, biliary tract and pancreatic disease
LIVER BIOCHEMISTRY AND LIVER FUNCTION TESTS
SYMPTOMS AND SIGNS OF LIVER DISEASE
JAUNDICE
HEPATITIS
NON - ALCOHOLIC FATTY LIVER DISEASE (NAFLD)
CIRRHOSIS
COMPLICATIONS AND EFFECTS OF CIRRHOSIS
LIVER TRANSPLANTATION
TYPES OF CHRONIC LIVER DISEASE AND CIRRHOSIS
PRIMARY SCLEROSING CHOLANGITIS
BUDD - CHIARI SYNDROME
LIVER ABSCESS
LIVER DISEASE IN PREGNANCY
LIVER TUMOURS
GALLSTONES
THE PANCREAS
CARCINOMA OF THE PANCREAS
NEUROENDOCRINE TUMOURS OF THE PANCREAS

5. Haematological disease

Haematological disease
ANAEMIA
Assessment and treatment of suspected neutropenic sepsis
HAEMOLYTIC ANAEMIA
INHERITED HAEMOLYTIC ANAEMIAS
ACQUIRED HAEMOLYTIC ANAEMIA
MYELOPROLIFERATIVE DISORDERS
THE SPLEEN
BLOOD TRANSFUSION
THE WHITE CELL
HAEMOSTASIS AND THROMBOSIS
THROMBOSIS
THERAPEUTICS

6. Malignant disease

Malignant disease
MYELOABLATIVE THERAPY AND HAEMOPOIETIC STEM CELL TRANSPLANTATION
THE LYMPHOMAS
THE PARAPROTEINAEMIAS
PALLIATIVE MEDICINE AND SYMPTOM CONTROL

7. Rheumatology

Rheumatology
COMMON INVESTIGATIONS IN MUSCULOSKELETAL DISEASE
COMMON REGIONAL MUSCULOSKELETAL PROBLEMS
BACK PAIN
OSTEOARTHRITIS
INFLAMMATORY ARTHRITIS
THE SERONEGATIVE SPONDYLOARTHROPATHIES
Clinical features, Investigations
INFECTION OF JOINTS AND BONES
AUTOIMMUNE RHEUMATIC DISEASES
SYSTEMIC INFLAMMATORY VASCULITIS
DISEASES OF BONE
THERAPEUTICS

8. Water, electrolytes and acid–base balance

WATER AND ELECTROLYTE REQUIREMENTS
BODY FLUID COMPARTMENTS
REGULATION OF BODY FLUID HOMEOSTASIS
PLASMA OSMOLALITY AND DISORDERS OF SODIUM REGULATION
DISORDERS OF POTASSIUM REGULATION
DISORDERS OF MAGNESIUM REGULATION
DISORDERS OF ACID - BASE BALANCE
THERAPEUTICS

9. Renal disease

Renal disease
INVESTIGATION OF RENAL DISEASE
GLOMERULAR DISEASES
NEPHROTIC SYNDROME
URINARY TRACT INFECTION
TUBULOINTERSTITIAL NEPHRITIS
HYPERTENSION AND THE KIDNEY
RENAL CALCULI AND NEPHROCALCINOSIS
URINARY TRACT OBSTRUCTION
ACUTE RENAL FAILURE/ACUTE KIDNEY INJURY
CHRONIC KIDNEY DISEASE
RENAL REPLACEMENT THERAPY
CYSTIC RENAL DISEASE
TUMOURS OF THE KIDNEY AND GENITOURINARY TRACT
DISEASES OF THE PROSTATE GLAND
TESTICULAR TUMOUR
URINARY INCONTINENCE

10. Cardiovascular disease

COMMON PRESENTING SYMPTOMS OF HEART DISEASE
INVESTIGATIONS IN CARDIAC DISEASE
CARDIAC ARRHYTHMIAS
HEART FAILURE
ISCHAEMIC HEART DISEASE
RHEUMATIC FEVER
VALVULAR HEART DISEASE
PULMONARY HEART DISEASE
MYOCARDIAL DISEASE
CARDIOMYOPATHY
PERICARDIAL DISEASE
SYSTEMIC HYPERTENSION
ARTERIAL AND VENOUS DISEASE
ELECTRICAL CARDIOVERSION
DRUGS FOR ARRHYTHMIAS
DRUGS FOR HEART FAILURE
DRUGS AFFECTING THE RENIN - ANGIOTENSIN SYSTEM
NITRATES, CALCIUM - CHANNEL BLOCKERS AND POTASSIUM - CHANNEL ACTIVATORS

11. Respiratory disease


Respiratory disease
TUBERCULOSISnd
DIFFUSE DISEASES OF THE LUNG PARENCHYMA
OCCUPATIONAL LUNG DISEASE
CARCINOMA OF THE LUNG
DISEASES OF THE CHEST WALL AND PLEURA
DISORDERS OF THE DIAPHRAGM

12. Intensive care medicine

Intensive care medicine

13. Drug therapy, poisoning, and alcohol misuse

Drug therapy, poisoning, and alcohol misuse

14. Endocrine disease

Endocrine disease
PITUITARY HYPERSECRETION SYNDROMES
THE THYROID AXIS
MALE REPRODUCTION AND SEX
FEMALE REPRODUCTION AND SEX
THE GLUCOCORTICOID AXIS
THE THIRST AXIS
DISORDERS OF CALCIUM METABOLISM
DISORDERS OF PHOSPHATE CONCENTRATION
ENDOCRINOLOGY OF BLOOD PRESSURE CONTROL
DISORDERS OF TEMPERATURE REGULATION
THERAPEUTICS

15. Diabetes mellitus and other disorders of metabolism

DIABETES MELLITUS
DIABETIC METABOLIC EMERGENCIES
COMPLICATIONS OF DIABETES
SPECIAL SITUATIONS
HYPOGLYCAEMIA IN THE NON - DIABETIC
DISORDERS OF LIPID METABOLISM
THE PORPHYRIAS

16. The special senses

THE EAR
THE NOSE AND NASAL CAVITY
THE THROAT
THE EYE

17. Neurology

COMMON NEUROLOGICAL SYMPTOMS
COORDINATION OF MOVEMENT
THE CRANIAL NERVES
COMMON INVESTIGATIONS IN NEUROLOGICAL DISEASE
UNCONSCIOUSNESS AND COMA
STROKE AND CEREBROVASCULAR DISEASE
EPILEPSY AND LOSS OF CONSCIOUSNESS
NERVOUS SYSTEM INFECTION AND INFLAMMATION
HYDROCEPHALUS
HEADACHE, MIGRAINE AND FACIAL PAIN
SPINAL CORD DISEASE
DEGENERATIVE NEURONAL DISEASES
DISEASES OF THE PERIPHERAL NERVES
MUSCLE DISEASES
MYOTONIAS
DELIRIUM
THERAPEUTICS

18. Dermatology

Dermatology

KEYWORD : Phác Đồ Chữa Bệnh, Bệnh Viện Bạch Mai, Từ Dũ , 115, Bình Dân, Chấn thương chỉnh hình, Chợ Rẫy, Đại học Y Dược, Nhân Dân Gia Định, Hoàn Mỹ, Viện Pasteur, Nhi Đồng Ung bướu, Quân Đội 103, 108,Phụ Sản Trung Ương, Bộ Y Tế,Phòng Khám, Hà Nội, Hải Dương, Thái Bình, Hồ Chí Minh, Sài Gòn, Đà Nẵng, Huế, Vinh, Đồng Nai, Bình Dương, Hải Phòng, Quảng Ninh, Hiệu Quả Cao, Chữa Tốt, Khỏi Bệnh, Là Gì, Nguyên Nhân, Triệu Chứng, Ăn Uống, Cách Chữa, Bài Thuốc - Bài Giảng - Giáo Án - Điện Tử
Thông Tin Trên Web Là Tài Liệu Lưu Hành Nội Bộ Cho Các Bạn Sinh Viên - Y, Bác Sĩ Tham Khảo : Liên Hệ : Maikhanhdu@gmail.com