Veterinary Cytology Techniques Quiz

Cytology Diagnostic Aids

• Cytology is the study of cells, while histology is the study of tissues.
• Abnormal cells and cells indicating inflammation/infection are key targets for cytology.
• Samples are also analyzed for bacteria, fungi, and protozoa.
• Biochemical tests (protein and others) are performed on samples.
• The general appearance of the sample is also assessed.

Fluid Samples in Cytology

• Fluid samples include:
  • Urine sediment
  • Thoracentesis/pericardiocentesis/abdominocentesis fluids from body cavities
  • Joint fluid (CSF)
  • Bronchus wash
  • Prostate tap
• Other samples include:
  • Swabs
  • Scrapings (scrape)
  • Impression smears
  • Endoscope brush fine needle aspirate

'-centesis' Procedures

• '-centesis' is a Greek word meaning 'to puncture'
• Procedures like thoracentesis/thoracocentesis, abdominocentesis, pericardiocentesis, arthrocentesis, and myelocentesis are used.
• These procedures use needles and syringes to collect fluids.
• Sometimes, these procedures are referred to as "taps".

Body Cavity Effusions

• Illustrations show the visceral pleura, lungs, parietal peritoneum, and peritoneal cavity.
• This section discusses the various body cavities.

Abdominocentesis Procedure

• A needle/butterfly (19g) is used, attached to a syringe via a 3-way tap.
• Sterile preparation is needed, and a local anesthetic (LA block) may be necessary.
• The animal is held in a standing or lateral position.
• Manual restraint is used.
• The puncture site is on the most dependent part of the ventral midline or in one of the four quadrants.

Thoracentesis Procedure

• An intravenous catheter (19g) or needle/butterfly is used, connected to a syringe via a 3-way tap.
• Sterile preparation of the puncture site is needed, and a local anesthetic (LA block) may be administered.
• Animals are restrained either sternal or standing.
• Light sedation may be used.
• The 7th intercostal space, ventral 1/3 is targeted at an angle to minimize the risk of puncturing the lung.

Pericardiocentesis Procedure

• An intravenous catheter (19g) or needle/butterfly is connected to a 3-way tap syringe.
• Sterile preparation and a local anesthetic (LA block) are required, and the side is decided after an x-ray.
• The animals are usually placed in a sternal recumbency.
• Manual restraint or mild sedation is usually employed.
• The 4th or 5th intercostal space is targeted.

Fluid Analysis

• Methods used to analyze fluids include:
  • Culture and sensitivity tests
  • Haematology analysis (e.g., PCV)
  • Microscopy (e.g., bacteria, cells)
  • Refractometer for protein measurement
  • Urinalysis
  • Biochemistry tests

Effusion Sample Evaluation

• The appearance (color, smell, turbidity, flocculation), total protein (TP), total nucleated cell count (TNCC), cytology (smear examination), and biochemistry tests (e.g., creatinine, bilirubin) are analyzed for effusions.

Classifying Effusions

• Total protein (TP) and total nucleated cell count (TNCC) are used to classify effusions.
• TP is measured with refractometers, urine test strips, or biochemical analyzers, aiming for albumin and globulin concentration.
• TNCC is measured with hematology analyzers or hemocytometers using special slides.

Causes of Effusions

• Effusions can be caused by leaks from internal organs like the bladder, gallbladder, or gut.
• Torn blood vessels can lead to blood or lymph leakage.
• Intact blood vessels can also cause leakage.
• Different types of organs are listed (digestive, biliary, urinary)

Types of Effusion: Leak from Viscus

• Effusion A: initially low nucleated cell count, low protein, high creatinine (greater than twice serum levels).
• Effusion B: initially low nucleated cell count, low protein, green-brown or yellow-brown color, high bilirubin greater than twice serum levels).
• Effusion C: high nucleated cell count, high protein, possible foul odor, and presence of food debris.

Leak from a Torn Blood Vessel

• Blood vessels leaking can cause effusions like haemothorax (blood in the chest cavity) and hemoabdomen (blood in the abdominal cavity).
• Lymph vessels leaking causes effusions called chylothorax (lymph in chest cavity) and chyloabdomen (lymph in abdominal cavity).

Types of Effusion: Vessel Tears

• Effusion D: Very high nucleated cell count (especially lymphocytes), high protein concentration, and high fat content.
• Effusion F: High red blood cell count (PCV > 5%), high nucleated cell count, and high protein.

Effusion: Leakage from Blood Vessels

• Low protein transudate: low protein levels in plasma result in water leakage.
• High protein transudate: Increased blood pressure leads to water and protein leakage.
• Exudate: Leaky capillaries due to inflammation result in water, protein, and cell leakage,

Types of Effusion: Transudate and Exudate

• Low protein transudate: low nucleated cell count, low total protein.
• High protein transudate: low nucleated cell count, high total protein.
• Exudate: high nucleated cell count, high total protein.
• Potential causes for each type are discussed.

Types of Effusion

• A table summarizes effusions, noting the total nucleated cell count, total protein, appearance, and other features (e.g., creatinine elevation, bilirubin elevation). This table differentiates various effusion types (Torn Viscus, Torn Vessels, Leaky Vessels).

Myelocentesis: Spinal Tap

• Myelocentesis is used to examine cerebrospinal fluid (CSF).
• Indications include investigating central nervous system (CNS) diseases of unknown cause.
• Contraindications are general anesthesia (GA) and increased intracranial pressure, possibly related to brain herniation.

CSF Sampling

• CSF is collected from cisterns (widened spaces).
• General anesthesia (GA) and sterile preparation are required for spinal puncture using a spinal needle.
• Fluid is allowed to drip out and not collected using a syringe (1ml/5kg).
• Plain and EDTA tubes are used for cell collection.

Arthrocentesis: Joint Tap

• Arthrocentesis is used to collect synovial fluid from joints.
• Indications include joint disease, joint effusion, polyarthritis, suspected infectious arthritis, and pyrexia of unknown origin (PUO).

Arthrocentesis Sample Collection

• General anesthesia (GA) or heavy sedation/local anesthesia (LA) is employed.
• Aseptic preparation and use of sterile gloves are important to avoid contamination.
• A syringe attached to a needle is used to collect the fluid, and gentle suction is used.
• The amount collected from a dog is usually 0.1-1.0 milliliters per joint.
• Collected fluid is stored in EDTA, plain, and blood culture bottles. A smear/squash is also typically made.

Normal Appearance of Joint Fluid

• Normal joint fluid is clear to slightly yellow.
• It is clear and viscous (thick).

Respiratory Tract Cytology

• This section discusses cytology of the respiratory tract.
• The respiratory tract is examined for various diseases.
• Sample collection methods include transtracheal aspiration, endotracheal tubes, and bronchoalveolar lavage (BAL).

Obtaining Samples

• Transtracheal aspiration, endotracheal tubes, and flexible endoscope (bronchoalveolar lavage [BAL]) are used for sample collection.

Why do we perform respiratory tract cytology?

• It's used to investigate chronic airway/lung diseases.
• This is especially done when inflammation, infection, or neoplasia is suspected.

Bronchoalveolar Lavage (BAL)

• General anesthesia(GA) is used.
• Oxygen therapy (before and 10 minutes after) is monitored closely.
• Bronchodilators may be needed, especially for cats.
• A large volume of saline is injected into a part of the lung.
• The fluid is aspirated, improving sample quality by coupage.
• Collected samples are stored in plain, EDTA, and for culture.

Fine Needle Aspirate (FNA)

• Fine-needle aspiration is used to diagnose lumps or bumps.
• Cells are removed using a needle.

FNA Indications

• It differentiates a lump/mass.
• Identifying and examining masses that may be infected, injured, inflamed or cancerous.
• Assisting in determining the boundaries for surgical removal.
• Performed on conscious patients.

Method: With Aspiration

• Description of steps in performing fine-needle aspiration with aspiration.

Method: Without Aspiration

• Capillary action pushes cells up the needle, used for masses where cells break easily, and when rupturing cells is a concern (lymphoma).

Needle and Syringe Size

• Needle sizes (23-25g for soft masses, 21-22g for firm masses) are pertinent.
• Syringe volume matters only with aspiration.
• Aspiration volumes for soft masses are 1-3ml, and >3ml for firm masses.

Potential Problems

• Problems in performing FNA include:
  • Missing the target
• Having necrotic tissue or pus in the center
• Difficulties with fibrous or scar tissue
• Benign tumors near malignant tumors

Fine Needle Aspiration Device

• Device to precisely manage pressure during FNA procedure
• Helps to obtain a proper sample

FNA: Slide Preparation

• The expelled sample is placed in the middle of a slide and covered with a second slide.
• A spreader is used to smoothly spread the sample without causing cell damage. Using a second slide on top, avoids pressure that could rupture cells.
• Frequently, a spreader produces the best smear/squash.

Summary

• Cytology involves extracting and examining cells from the body under a microscope.
• Cytology can be done on bodily fluids (e.g., effusions, cerebrospinal fluid, joint fluid).
• Cytologic samples like lavage samples, solid masses (e.g., needle aspirations, bone marrow), and effusions are collected.
• Effusion analysis often involves identifying proteins and cells in the fluid to determine fluid type.

Test your knowledge on the techniques and considerations involved in veterinary cytology and fluid analysis. This quiz covers topics such as needle size, syringe volume, myelocentesis, and effusion characteristics. Perfect for veterinary students and professionals alike!