Avaliação semiológica e diagnóstico em pequenos animais - Aula 16.3

Summary

In this class, the focus is on sample collection for imaging diagnosis, specifically targeting lymph nodes. The script covers fine needle aspiration (FNA) and biopsy techniques, including both closed and open methods. The procedure, guided by ultrasound, is described in detail, explaining the use of fine needles, punches, and large biopsy needles to collect tissue samples. Contraindications for each method are emphasized, such as patient medication, large blood vessels, and deep lymph nodes. The importance of proper training, safety measures, and anesthesia during these procedures is also highlighted, ensuring effective and accurate results for histopathological analysis.

Takeaways

• 😀 PFA (Fine Needle Aspiration) is a minimally invasive procedure that uses a fine needle, guided by ultrasound, to collect cells for cytology.
• 😀 Punch biopsy is a method involving a sterile punch tool to collect tissue samples, either superficially or from deeper organs, and is used when larger samples are needed.
• 😀 Closed biopsy involves using a large needle with a vacuum mechanism to collect tissue under ultrasound guidance, while open biopsy requires a surgical incision to collect tissue.
• 😀 PFA should be avoided in cases where the practitioner lacks sufficient training or experience, as it requires precision and careful technique.
• 😀 If an animal is on anti-inflammatory or steroidal medication, PFA may produce unreliable results due to masking of cytological changes.
• 😀 PFA should be avoided if there is significant vascularization in the area, particularly if large blood vessels cannot be avoided during the procedure.
• 😀 For lesions with suspected cysts or abscesses, a closed biopsy is preferred to prevent rupture and the spread of infection or cancerous cells.
• 😀 Closed biopsy may not be recommended if the lesion is highly vascularized, as there is a higher risk of bleeding and complications.
• 😀 All biopsy and aspiration procedures require general anesthesia to ensure the safety and comfort of the animal, with careful management of pain and stress.
• 😀 Practicing on cadavers and gaining sufficient training in a controlled environment is crucial before performing these techniques on live animals.

Q & A

What is the focus of today's lesson in the script?

The focus of today's lesson is on the collection of samples for diagnostic imaging, specifically targeting lymph nodes, and understanding the different techniques like fine-needle aspiration (FNA) and biopsy methods.

What are the key techniques discussed for sample collection?

The key techniques discussed are fine-needle aspiration (FNA), punch biopsy, and both open and closed biopsy methods.

How does the closed biopsy technique work?

The closed biopsy technique involves using a large needle with a vacuum mechanism, guided by ultrasound. The needle enters the organ, and a cutting blade within the needle collects a tissue sample, which is then sent for histopathological analysis.

What are the main indications for performing fine-needle aspiration (FNA)?

Fine-needle aspiration is indicated when the practitioner has sufficient experience and training, when there is no significant vascularization at the site, and when the lesion is not located in an area with high-risk structures, such as large blood vessels.

What contraindicates the use of fine-needle aspiration?

Contraindications for fine-needle aspiration include a lack of experience, the presence of larger blood vessels at the site (detected via Doppler imaging), when the lesion is deep or near major vessels, and when the lesion is a cyst or abscess that could rupture during aspiration.

What is the open biopsy technique, and when is it used?

The open biopsy technique involves making an incision to access the tissue directly, allowing for the removal of a tissue fragment using a scalpel. It is used when fine-needle aspiration is not feasible or safe due to the location or nature of the lesion.

What are the risks associated with the closed biopsy technique?

Risks associated with the closed biopsy technique include potential complications from the large needle, such as bleeding or damaging surrounding tissues, especially in areas with large blood vessels or cavities.

What should be done if an animal is on anti-inflammatory or steroidal medication before a biopsy?

If the animal is on anti-inflammatory or steroidal medication, it is recommended to wait for a period before performing the biopsy to avoid masking cytological results, which could affect the accuracy of the diagnosis.

Why is general anesthesia required for biopsy procedures?

General anesthesia is required for biopsy procedures to ensure that the animal remains still and comfortable throughout the procedure. It also helps manage pain, as the needle used can cause significant discomfort.

What are the necessary steps for ensuring a safe biopsy procedure?

The necessary steps for ensuring a safe biopsy include performing proper antisepsis using alcohol, iodine, or chlorhexidine, sterilizing all equipment, conducting pre-operative exams (like ECGs), and ensuring the animal is under general anesthesia. A sterile surgical field is also crucial to prevent infections.