What is Hypertensive Nephropathy

Hypertensive Nephropathy is a disease of the kidneys.

The vasculature of the kidneys is damaged with an increase in blood pressure (high blood pressure).

Statistics on Hypertensive Nephropathy

The incidence of this condition follows closely the incidence and duration of high blood pressure throughout the population.

There are two types of this condition including benign nephrosclerosis and malignant nephrosclerosis. Some degree of benign nephrosclerosis can be seen in most individuals over the age of 60 years. Malignant nephrosclerosis however, is an uncommon condition occurring only in 1-5% of patients with hypertension.

Risk Factors for Hypertensive Nephropathy

Benign Nephrosclerosis:

1. Hypertension
2. Diabetes mellitus (Type 1, Type 2)

Malignant Nephrosclerosis:

1. Malignant hypertension (Diastolic blood pressures in excess of 130mm Hg)
2. Male gender
3. People of colour
4. Pre-existing hypertension
5. Pre-existing renal disease

Progression of Hypertensive Nephropathy

Benign Nephrosclerosis:

This condition will rarely result in renal failure. As some renal damage has occurred, patients may be considered to have diminished renal reserve and are therefore less equipped to cope with the stress of surgery or acute illness. Measures must be taken during illness and prior to surgery to ensure that the kidneys are protected from further avoidable injury.

Malignant nephrosclerosis:

This condition will only occur in the context of severe hypertension with diastolic blood pressure in excess of 130mm Hg. Patients will usually have a pre-existing renal disease which has progressed to induce malignant hypertension. At the onset of escalating blood pressure, protein and blood may appear in the urine. Hours to days later, renal function begins to diminish and the patient will quickly develop renal failure. This represents a medical emergency and every effort must be made to reduce blood pressure to preserve renal function.

How is Hypertensive Nephropathy Diagnosed?

Blood tests may be required to determine how well the kidneys are functioning. A collection of urine over 24 hours may also be required to gauge the severity of kidney disease related to hypertension.

Prognosis of Hypertensive Nephropathy

Benign nephrosclerosis:

As the name suggests, this condition will rarely result in renal failure. Patients who develop this condition will have decreased renal reserve and may not cope very well with acute illness and surgical procedures. Between 1-5% of patients with this condition with develop renal failure at some stage in the disease process.

Malignant nephrosclerosis:

With modern therapy, 75% of patients are able to survive more then five years from the onset of disease. The earlier that treatment is initiated, the more kidney will be preserved and the greater the renal function on resolution of the condition.

How is Hypertensive Nephropathy Treated?

Control of hypertension is central to the management of both malignant and benign forms of the disease. This is achieved using antihypertension medication to essentially remove the stimulus for further kidney damage. The importance of antihypertension medication must be stressed to improve compliance to antihypertensive therapy.

In the case of malignant nephrosclerosis, efforts to reduce blood pressure must be more aggressive as the renal damage is accelerated in this form of disease. Admission to hospital is the rule and intravenous drugs may be used to hasten the reduction of blood pressure and thereby quickly prevent any further renal damage from occurring.

Aggressive reduction of blood pressure – Use of drugs such as frusemide, thiazide diuretics and hydralazine will rapidly reduce blood pressure and may save renal function if used early enough.

In many cases, the patient may develop renal failure that required close observation with many blood tests. Of the acute renal failure cannot be controlled by conservative means, then dialysis may be required to enable eventual recovery from the disease.

Hypertensive Nephropathy References

[1] Braunwald, Fauci, Kasper, Hauser, Longo, Jameson. Harrison’s Principles of Internal Medicine. 15th Edition. McGraw-Hill. 2001.
[2] Cotran, Kumar, Collins 6th edition. Robbins Pathologic Basis of Disease. WB Saunders Company. 1999.
[3] Kumar P, Clark M. CLINICAL MEDICINE. WB Saunders 2002 Pg 545-549.
[4] Longmore M, Wilkinson I, Torok E. OXFORD HANDBOOK OF CLINICAL MEDICINE. Oxford University Press. 2001.