8. Biopsy Adequacy
• The number of glomeruli in the sample is the major
determinant of whether the biopsy will be diagnostically
informative. A typical useful biopsy sample will contain
10 to 15 glomeruli .
• An adequate biopsy should provide samples for :
immunohistology and electron microscopy (EM).
• Immunohistology is provided by either
immunofluorescence on frozen material or
immunoperoxidase on fixed tissue, according to local
protocols .
• cores should be viewed after being taken under
microscope to ensure that they adequate
9. Biopsy adequacy
• Cortex and medulla
• 1-2 glomeruli EM
• 3-5 glomeruli IF
• 6 glomeruli (native kidney)
• 10 glomeruli (renal allograft)
10.
11. Informed Consent
Answering 5W Questions
• The patient has the rights to get answers for these
basic questions:
What?
• Piece from the kidney
Why?
• Guide treatment
• Tell the prognosis
How?
• Local anesthesia
• US/CT guided or others
• Rest in bed for 8h
• What is the risk benefit?
• What are the precautions
13. Precautions
• Standard of care: Precautions (CBC, Coagulation
profile, etc.
• Impact of patient and procedure on blood
transfusion:
• Needle gauge
• Number of needle passes
• Use of anti-platelets
• Age
• Serum creatinine
• Blood pressure
15. Contraindications to Renal
Biopsy
bleeding diathesis
Inability of the patient to comply with instructions
(Sedation or in extreme cases general anesthesia
( may be necessary)
Relative contraindications to renal biopsy are
Hypertension (>160/95 mm Hg), hypotension,
perinephric abscess, pyelonephritis, hydronephrosis,
severe anemia, large renal tumors, and cysts.
• The solitary functioning kidney has been considered a
contraindication to percutaneous biopsy, and risk of
biopsy is reduced by direct visualization at open biopsy.
20. Renal Biopsy Technique
Percutaneous native Renal Biopsy
• Biopsy is performed by nephrologists
• Continuous (real-time) ultrasound guidance
• Disposable automated biopsy needles. (16-gauge
needles)
• The patient is prone, and a pillow is placed under the
abdomen at the level of the umbilicus to straighten the
lumbar spine and to splint the kidneys.
21.
22.
23. • Ultrasound is used to localize the lower pole of the kidney
(usually the left kidney).
• A pen mark is used to indicate the point of entry of the biopsy
needle.
• The skin is sterilized with povidone-iodine (Betadine) . A sterile
fenestrated sheet is placed over the area to maintain a sterile
field.
• Local anesthetic (2% lidocaine ) is infiltrated into the skin at the
point previously marked.
• the ultrasound probe is covered in a sterile sheath.
• A stab incision is made through the dermis to ease passage of
the biopsy needle.
• Under ultrasound guidance, a 10-cm, needle is guided to the
renal capsule.
• As the needle approaches the capsule, the patient is instructed
to take a breath until the kidney is moved to a position such that
the lower pole rests just under the biopsy needle, and then to
stop breathing.
24.
25. • The biopsy needle tip is advanced to the renal
capsule, and the trigger mechanism is released, firing
the needle into the kidney .
• The needle is immediately withdrawn, the patient is
asked to resume breathing, and the contents of the
needle are examined .
26.
27. • under an operating microscope to ensure that
renal cortex has been obtained .
• A second pass of the needle is usually necessary
to obtain additional tissue for immunohistology and
EM.
• If insufficient tissue is obtained, further passes of
the needle are made.
• However, passing the needle more than four
times is
• associated with a modest increase in the post
biopsy . complication rate.
• Once sufficient renal tissue has been obtained, the
skin incision is dressed and the patient rolled
directly into bed for observation.
28.
29.
30. Post biopsy Monitoring
• After the biopsy, the patient is placed supine and
subjected to strict bed rest for 6 to 8hours.
• The blood pressure is monitored frequently
• urine examined for visible hematuria
• and the skin puncture site examined for excessive
bleeding.
• If there is no evidence of bleeding after 6 hours, the
patient is sat up in bed and subsequently allowed
• to move.
• If visible hematuria develops, bed rest is continued
until the bleeding settles.
