A medical brushing is a procedure that uses a small, specially designed brush to gather cellular material from the surface of internal tissues. The primary advantage of this method is its minimally invasive nature, allowing for the collection of diagnostic samples without complex surgical interventions. This technique provides information directly from the tissue surface where abnormalities often first appear.
What Are Brushings Used For?
Medical brushings are widely used for diagnostics and screening to detect cellular changes that may indicate disease. For example, a brushing of the cervix collects cells to screen for precancerous transformations, similar to a Pap test. Brushings of the esophagus can also monitor patients with conditions like Barrett’s esophagus, which can precede esophageal cancer, allowing for early identification of abnormal cells.
Beyond cancer screening, this method helps identify infectious agents. A brushing from the lining of the mouth or respiratory tract can collect samples to test for fungi or viruses. For example, bronchial brushings are used to gather material from the lungs to diagnose infections or inflammatory conditions, especially when an infection is suspected but not confirmed by other means.
The procedure also has a role in monitoring chronic diseases. For individuals with inflammatory conditions of the digestive tract or lungs, periodic brushings can help track the cellular response to treatment or disease progression. By examining the collected cells, physicians gain insights into the underlying inflammatory processes to make informed decisions about patient care.
The Brushing Procedure
The procedure uses a small, sterile brush with soft, flexible bristles, with the design selected for the specific tissue being sampled. A clinician carefully sweeps or rotates the brush against the targeted surface. This action dislodges a thin layer of superficial cells that adhere to the bristles for analysis.
Accessing the target site depends on its location. For areas like the bronchi or the bile duct, an endoscope is used, with the brush passed through a channel to reach the site. For more accessible areas, such as the inside of the mouth, the brush can be applied directly.
Regardless of the access method, the brushing itself is a quick process. Patients may experience a mild scraping or tickling sensation, but significant pain is uncommon. The procedure is well-tolerated and can often be performed in an outpatient setting.
Analyzing the Collected Cells
Once collected, the cells are immediately prepared for examination. The brush may be rolled onto a glass microscope slide to create a smear, which is preserved with a fixative. Alternatively, the brush head is placed into a vial with a liquid preservative, which helps maintain cell structure and allows for a more evenly distributed sample.
The principal method of analysis is cytology, the microscopic examination of cells by a specialized physician called a cytopathologist. They look for abnormalities in cellular features, such as nuclear-to-cytoplasmic ratio, variations in cell size and shape, and changes in cell organization. These clues help determine if the cells are normal, inflamed, precancerous, or malignant.
Modern molecular testing has expanded the utility of brushing samples, as the same material can be used for advanced diagnostics. For example, a cervical sample can be analyzed for the DNA of high-risk human papillomavirus (HPV) strains. In other contexts, cells can be tested for specific genetic mutations or biomarkers associated with certain cancers to help guide diagnosis and treatment.