The TANDEM Cat® Feline Mammary Duct Impaction Severity Index (FMDISI) is an observational framework used to identify, document, and communicate mammary duct congestion and impaction in cats.
The scale allows team members to:
Recognize mammary duct abnormalities
Standardize documentation
Improve communication between staff members
Provide structured observations to guardians
Support appropriate veterinary referral when indicated
The FMDISI is an observational tool and is not intended to diagnose medical conditions.
Feline Mammary Duct Impaction (FMDI) occurs when glandular material accumulates within a mammary duct and is unable to drain normally.
Affected glands may become:
Enlarged
Firm
Nodular
Congested
In some cases, thick glandular material may be expressed from the nipple during routine handling or grooming.
Unlike mastitis, FMDI is not necessarily associated with infection.
Many mammary abnormalities are discovered during grooming rather than veterinary examination because groomers routinely:
Handle the entire body
Separate the coat
Bathe the abdomen
Observe skin and glandular structures
Early identification allows guardians to seek veterinary evaluation when appropriate.
Slight nipple fullness
Small glandular thickening
Minimal discharge
Palpable nodules
Distinct gland enlargement
Thick glandular material
Large masses
Significant swelling
Inflammation
Discomfort during handling
Mammary tissue soft and flat
No palpable fullness
No discharge
No gland enlargement
No evidence of mammary duct obstruction.
No intervention required.
Document only if relevant to the examination.
Slight fullness around nipple
Small glandular thickening
Minimal expression possible
Early duct accumulation.
Document findings.
Continue observation.
No active intervention typically required.
Distinct glandular enlargement
Palpable nodules
Thick glandular material expressed with gentle pressure
Moderate duct obstruction.
Document location and findings.
Notify guardian.
Recommend monitoring and veterinary discussion if persistent.
Firm glandular swelling
Significant enlargement
Thick waxy or paste-like material
Significant duct blockage.
Document thoroughly.
Notify guardian.
Recommend veterinary evaluation.
Photograph findings when appropriate and consented.
Large glandular mass
Dense material present
Possible inflammation
Possible irritation
Significant enlargement
Advanced obstruction requiring veterinary assessment.
Infection, mastitis, or neoplastic processes must be ruled out by a veterinarian.
Immediate documentation.
Immediate guardian notification.
Strong recommendation for veterinary evaluation.
Leadership notification when appropriate.
Whenever mammary abnormalities are observed, record:
Identify affected gland whenever possible.
Example:
Left cranial abdominal gland.
Assign FMDISI score.
Example:
FMDISI Grade 2.
Describe observations objectively.
Example:
Moderate gland enlargement with thick white glandular material expressed during bathing.
Document comfort level.
Example:
No discomfort observed.
or
Cat demonstrated sensitivity during palpation.
During abdominal assessment, a moderate enlargement was observed near the right caudal mammary gland. Gentle expression produced thick white glandular material. Cat remained tolerant throughout examination. Findings consistent with FMDISI Grade 2. Guardian informed and advised to discuss findings with veterinarian if changes persist or worsen.
When mammary abnormalities are identified:
Use gentle handling
Minimize palpation
Observe carefully
Prioritize comfort
Document findings
Repeatedly manipulate glands
Force expression
Attempt aggressive removal
Cause discomfort for diagnostic purposes
The goal is observation, not extraction.
Recommend veterinary evaluation when any of the following are present:
Painful swelling
Warmth
Redness
Persistent discharge
Rapid enlargement
Ulceration
Fever
Lethargy
Multiple affected glands
Grade 3 or Grade 4 findings
FMDI observations should never be presented as a diagnosis.
Potential veterinary differentials may include:
Mammary duct impaction
Mastitis
Mammary hyperplasia
Mammary tumors
Abscess formation
Inflammatory conditions
Diagnosis remains the responsibility of a veterinarian.
This index works alongside:
TANDEM Cat® Matting Severity Scale
TANDEM Cat® Sound Sensitivity Scale (TCSSS)
Feline Glandular Expression Grading (FGEG)
Transitional Stress Anorexia (TSA) Protocol
Pre-Felt Somatic Entrapment Syndrome (PFSES)
Together these frameworks transform grooming observations into structured clinical information that supports better feline care.
Feline Mammary Duct Impaction is frequently discovered during grooming because of the extensive hands-on assessment involved in feline coat care.
The purpose of the FMDISI is to help staff consistently identify, document, communicate, and escalate mammary findings while maintaining a trauma-informed, observation-based approach that prioritizes feline comfort and safety.
Somatic Medicine recognizes that posture, movement, behavior, appetite, coat condition, touch tolerance, and environmental response are meaningful clinical signals. These related Cats in the City and TANDEM Cat® resources expand on the principles discussed above.