Reducing the risks of bleeding with FNAB

TOPIC: Percutaneous thyroid biopsy

Title: Bilateral thyroid hematomas after fine-needle aspiration causing acute airway obstruction.

Authors: Hor T & Lahiri SW.

Reference: Thyroid 18: 567-570, 2008

Summary

Background

Percutaneous fine-needle biopsy (FNB) of thyroid nodules has been universally accepted as the most economical, dependable, and easy evaluation of thyroid nodules. FNB provides the best triage of nodules for cancer. Adverse consequences are uncommon and serious complications rare.

Purpose

To communicate the third reported instance of acute obstruction of a patient’s airway caused by bilateral thyroid hematomas after fine-needle aspiration biopsy (FNAB). The authors present the case report and a literature review.

Case Report

The patient is a 62-year-old euthyroid woman with multiple illnesses including end-stage renal disease (on peritoneal dialysis) and weight loss who was taking 325 mg aspirin daily. Thyroid nodules were incidentally found on a computed tomography of the chest, which was done as part of an evaluation for possible malignancy. Her thyroid exam was notable for bilateral nodular enlargement. Thyroid ultrasound showed multiple hypoechoic lesions bilaterally with a dominant nodule in each lobe (1.35 x 0.78 x 1.5 cm in the mid-right lobe and 1.17 x 0.97 x 1.34 cm in the mid-left lobe). Ultrasound-guided biopsy of the 2 nodules was performed, using 25-gauge needles. Three punctures were made in the right nodule and two in the left nodule. The patient was quite anxious during the procedure, and intermittently strained her neck. There was no obvious bleeding during the procedure. At the end of the procedure, despite continuous pressure applied over both sides of the thyroid gland, expanding bilateral hematomas without tachypnea were observed. The hematomas continued to expand and 45 minutes later the patient presented dysphonia & tachypnea. A CT- scan showed an enlarged thyroid gland with low density areas in both lobes, consistent with intrathyroidal hemorrhage. There also was marked swelling in the prethyroid and subcutaneous tissues, consistent with diffuse hematoma. Laboratory testing was remarkable for normal PTT and aPTT but the platelet count was moderately decreased at 115,000/mL. The patient underwent surgical exploration of the neck. Bilateral thyroid hematomas and evidence of local bleeding were seen. The thyroid isthmus was removed. Surgical pathology showed benign thyroid nodules with focal papillary hyperplasia. The cytology from the FNA was negative for malignant cells, and consistent with bilateral colloid nodules.

Conclusions

The authors conclude that endocrinologists should be made more aware that thyroid hematoma is a rare but potentially life-threatening complication after FNAB, especially when certain conditions prevail, including aspirin or anticoagulant use, and illnesses that can cause coagulopathy (cirrhosis, end-stage renal disease). They advise that patients should be routinely screened prior to FNAB for increased risk factors for hemorrhage. If a high-risk patient is found to have thyroid nodules, the necessity of the procedure must be weighed against the potential danger of thyroid hemorrhage. If a decision is made to biopsy these patients, precautionary measures should be carried out such as fewer needle passes, less aggressive needle aspiration, and increased time taken to compress the area biopsied. If a significant thyroid hematoma develops, prompt evaluation and airway stabilization with possible emergency neck exploration will be life-saving.

Commentary

This article reinforces my belief that we may have gotten too complacent about FNB. I recently spoke about FNB and was admonished by a member of the audience that my advice to discontinue agents that interfere with coagulation of the blood before the procedure was over-cautious and unnecessary. Many in the audience agreed. All too often, FNB is thought to be safe even when a patient is taking anticoagulants.

In an excellent Editorial, Farwell & Leung (see Thyroid 18:491, 2008) concur that that FNAB’s morbidity of thyroid nodule is extremely low, but clinicians recommending FNAB should reflect on the risk/benefit ratio of the procedure. Complications of thyroid nodule FNAB are rare. Airway compromise arising from hematomas is the most serious complication but is exceedingly rare. Also serious and very uncommon is pneumothorax that may occur when the dome of the pleura is penetrated in the process of puncturing a nodule that is located at the thoracic inlet. Small hematomas and ecchymoses that resolve in several days are usually inconsequential and are the most common adverse incidents after FNAB. Others which are infrequent but may be more formidable include seeding the needle tract with carcinoma cells, chemical neuritis, transient vocal cord paralysis, infection, thyroid nodule infarction, local vascular thyroid proliferation, and acute and transient development of a symmetric goiter. Local discomfort is usually mild and transient and generally does not require local anesthesia. The patient’s anxiety about the procedure is common and usually responds to reassurance but, when extreme, may result in poor cooperation and movement during punctures and contribute to inadequate specimen and more severe bleeding. Farwell & Leung are very perceptive in recognizing that failure to make a diagnosis with FNAB is the most common, unacceptable consequence of the procedure. Unsatisfactory technique or sub-optimal specimens, which may be caused by excessive bleeding, result in repeat biopsy, contribute to additional cost, inconvenience, and risk, and may be responsible for unnecessary surgery.

FNAB is deceptively easy to perform and generally so safe that all manors of clinicians do it with minimal reflection. The test is usually performed without serious adverse effects (witness the few case reports of injury). But, there are untoward events that are not reported. Furthermore, biopsies that are performed while the patient has an increased risk of bleeding due to aspirin use or subclinical coagulopathy, and when more aggressive than necessary punctures are employed, may be associated with sub-optimal, bloody specimens, unsatisfactory cytology, disappointed patients, and rarely meaningful injury. Inadequate biopsies should be repeated, which unnecessarily adds to the cost and risk.

What can we do to reduce bleeding and improve cytology? I suggest a conservative approach to patient-preparation. Avoid aspirin or other agents that interfere with coagulation and remain alert to circumstances that may be associated with coagulopathy. Technique is of paramount importance. Perform a gentle, ‘atraumatic’ puncture. One should not penetrate muscle before entering the thyroid gland and should avoid lateral movement of the needle, which may lacerate the tissue. Ultrasound guidance of FNAB improves the harvest and diagnostic yield considerably and helps one assure that the needle tip is within the nodule at the instant of sampling. Reduced bleeding occurs when #25 or #27 gauge needles rather than larger bore needles are employed and the specimen/cytology results are just as good or better. One should not biopsy unless the patient is cooperative, remains motionless, and refrains from swallowing during the procedure. It may take several additional minutes to gain the patient’s confidence and cooperation (time well spent). This last precaution is particularly important in a pediatric or psychiatric population, a discussion which is beyond my expertise.

There is a way to do fine-needle biopsy without aspiration that reduces bleeding, may improve cytology, seems to yield a superior diagnostic rate, and probably results in reduced unsatisfactory specimens. For most situations, I have migrated to a non-aspiration technique first described in the 1980’s. Tissue pressure and capillary action (fine needle capillary biopsy, FNC) but not vacuum are employed to obtain a small, concentrated specimen in the shaft of a #25 or #27 gauge needle. The needle is held between thumb & index fingers and gently inserted into the nodule (with or without ultrasound-guidance). The needle is moved to and fro a few times and, once in the nodule, it may be rotated between the thumb and index finger to accomplish a 360º excursion of the bevel, which provides a mini-core of nodule cells. Lateral motion of the needle-tip, which may result in an incision and bleeding, is avoided. If a change in trajectory is desired, the needle is withdrawn from the nodule into the subcutaneous space and then redirected into another part of a nodule. The specimen is gently expelled from the needle shaft on to a slide with an air-filled syringe, and then spread. Tissue samples from FNC are reportedly as good or superior to FNA . FNC is associated with very little bleeding and the cyto-diagnostic yield is excellent. Interpretation may be easier and quicker because of reduced blood and diminished trauma-induced cellular artifacts. I suggest reserving FNA for the few nodules that do not yield a specimen by FNC technique.

In summary, this case report reminds us that although FNB of thyroid nodules is very safe, is the best way to achieve a reliable diagnosis, and provides optimal selection for or against surgery, serious consequences can occur (rarely). Therefore, one should always minimize the risk of bleeding. Additional precautions should especially be taken in patients who are at increased risk of bleeding. More emphasis should be given to gentle technique in this deceivingly simple procedure. Most importantly, since thyroid cancer is usually not very aggressive, we should conservatively judge the risks when we seek the benefits of FNB.

Summary and commentary prepared by Manfred Blum (Related to Chapter 6[d] of TDM)