The role of renal biopsy in nephrotic syndrome.BV Gandhi
Department of Nephrology, Jaslok Hospital & Research Centre, Bombay.
Keywords: Biopsy, Human, Nephrotic Syndrome, etiology,pathology,Sensitivity and Specificity,
My topic for the talk in issues in practical nephrology session is the Role of Renal Biopsy in Nephrotic Syndrome (NS). The introduction of renal biopsy in clinical practice by Inverson and Brun in 1951 has represented one of the most important advances in the field of Nephrology. Even today in spite of the flood of new and less invasive tests, renal biopsy is still considered by most nephrologists as an irreplaceable tool in diagnosis and prognosis and in deciding therapy in many renal diseases.
Let us start with the basics
The salient features of NS are: proteinuria > 3.5 gms/1.73 sq. m., hypoalbuminemia, hyperlipidemia and edema. Routine investigations done in such cases are: Detail history and physical examination followed by routine urinalysis, complete blood counts, BUN, Creatinine, 24 hour urinary proteins, Total proteins with A/G ratio and serum cholesterol level. In selected patients postprandial blood sugars, ANA, Anti DNA, serum protein electrophoresis, C3 and C4 are done. At times urine protein electrophoresis is also done to determine selectivity of proteinuria or Bence Jones protein.
The common causes of the Nephrotic Syndrome are shown in the [Table - 1].
Nephrotic Syndrome in pediatric and adult patients are of two distinct types (certain types of disease are very common in the pediatric group viz. Minimal change while in adult it is not so common). [Table:II] shows the patterns of NS in adult and pediatric group and their prevalence rates:
Most nephrologists refrain from doing a renal biopsy in the pediatric group of patients (less than 6 years) as most of them respond to therapy with prednisolone while in adults almost everyone performs a biopsy before starting therapy as most patients do not respond to standard therapy with steroid for eight to twelve weeks.
Before I go to the indications for a biopsy, I would like to enumerate the questions / treatment options in NS patients.
(1) Should NS be treated?
(2) Treatment options available at present include
(b) immunosuppressive therapy
(d) Plasma exchange and
(3) Which treatment to start and when to stop
(4) What are the side effects of therapy?
As with therapy, we need to answer some questions before we resort to a renal biopsy. Is a biopsy necessary in a given case or not? If so why? Will the biopsy provide us with more information than that obtained from routine tests? Is identification of the type of renal disease going to influence the prognosis and therapy? Renal biopsy will provide information as to the type and severity of renal disease and aid in the diagnosis, prognosis and guidelines for therapy.
Renal biopsy was first described by Ball in 1934 and later by Perez-Aza and Inverson and Brun in the early fifties. Modification of the original technique was described in 1954 by Mark and Muehrcke- (Prone position, Use of the exploring needle to gauge depth of the kidney and the use of Franklin modification of Vim- Silverman needle). Today most nephrologists use Tru- cut disposable biopsy needle or biopsy 'gun' and they perform the biopsy under ultrasound control to ensure a better yield.
1. Features suggesting a diagnosis other than minimal change nephropathy.
2. NS presenting in first year of life.
3. NS presenting after six years.
4. Failure to respond to adequate dose of steroid therapy in 28 days.
5. Frequently relapsing NS.
6. Steroid dependent NS.
7. Development of Steroid resistance
8. Change in clinical course.
9. Before starting immunosuppressive therapy.
10. Patient with renal insufficiency and NS.
The following complications may be encountered after renal biopsies. These include: a) Gross hematuria (5-7%) (b) Hemoperitoneum i) severe (0.21.4%) ii) Mild (85%) c) Arteriovenous fistula (15%) d) Aneurysm (rare) e) Renal dysfunction (rare) f) Puncture of other organs (rare).
a) Solitary kidneys
b) Renal mass
c) Advanced chronic renal failure
d) Active urinary infection
e) Uncontrolled hypertension
f) Coagulation disorders
g) Renal artery aneurysm
h) Perinephric abscess
i) Horsheshoe kidneys.
The treatment of NS will be dealt with by Dr. MK Mani. In my opinion, the therapy of NS has many limitations and multiple side effects. I would therefore recommend that if we cannot make a patient better with our therapy, then we should not make them any worse with the side effects of our therapy. I will therefore conclude with the following advice - Do a renal biopsy in patients when indicated and thereafter decide whether to treat them or not.
[Table - 1], [Table - 2]