When should I suspect hepatic portal microvascular dysplasia?

Common warning signs include persistent diarrhoea, decreased appetite, poor growth, or recurrent vomiting in puppies or kittens. If MVD is suspected, your vet will arrange blood tests and imaging, and may recommend a biopsy to confirm the diagnosis.

How will the vet test for and confirm this hepatic vascular abnormality?

Your vet will typically start with a biochemistry panel, urinalysis, and abdominal ultrasound. CT or liver biopsy may follow if more detailed information is needed. A specialist will interpret the combined results and advise on next steps.

Does treatment require long-term medication or dietary changes?

Most cases are managed primarily through prescription dietary changes. Whether long-term medication is needed depends on the clinical response and ongoing test results — follow your vet's recommendations for any adjustments.

What is the prognosis — can my pet live normally?

Prognosis varies by individual and disease severity. Many pets maintain a good quality of life with dietary management and regular monitoring. Discuss a long-term follow-up plan with your vet and attend check-ups as advised.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Hepatic Portal Microvascular Dysplasia in Dogs & Cats: Symptoms, Diagnosis & Care [2025]

Hepatic portal microvascular dysplasia (MVD) is a congenital vascular abnormality common in small-breed dogs. Most cases are mild and managed with dietary changes alone. Unlike portosystemic shunts, surgery is usually unnecessary and the prognosis is generally good.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ACVIM, National Taiwan University Veterinary Hospital

When to See a Vet

Requires immediate veterinary care (emergency)

•When seizures or brief loss of consciousness occur
•When there is persistent vomiting with obvious dehydration and weakness
•When vomit or stool contains a large amount of blood

Recommend scheduling a clinic visit soon (within 24-72 hours)

•When diarrhea persists for several days with no improvement
•Reduced appetite and continuously eating less than usual
•Markedly reduced spirits and decreased activity

01What signs suggest something is wrong?

In dogs and cats, digestive signs are most prominent — diarrhoea and reduced appetite are the most common complaints, and energy levels or growth may also be affected.

Chronic or intermittent diarrhoea with loose or discoloured stools
Reduced appetite or noticeably decreased food intake
Lethargy and lower-than-normal activity levels
Weight loss or growth retardation in young animals
Recurrent or intermittent vomiting

Seek emergency care immediately if you notice the following symptoms:

⚠️ Seek emergency care immediately if your pet has a seizure or loses consciousness
⚠️ Persistent vomiting with obvious dehydration or extreme weakness warrants urgent veterinary attention
⚠️ Visible blood in vomit or stools requires prompt veterinary evaluation

02How to assess the situation at home — key observations and when to seek emergency care

Thorough home monitoring and record-keeping before the appointment helps your vet quickly understand how the condition is progressing and identify possible causes.

Track frequency, consistency, and colour changes of diarrhoea episodes
Record short videos of bowel movements and daily activity for the vet to review
Weigh your pet daily and log trends in weight and food intake
Monitor water consumption, urine output, and changes in alertness or energy
Note when symptoms started and when they worsen or improve
If symptoms deteriorate rapidly, schedule a clinic visit without delay

03How will the vet diagnose this condition? Common tests explained

Your vet will use blood tests, urinalysis, and imaging to assess liver function, metabolic changes, and whether the liver structure is affected.

Complete blood count (CBC)

screens for infection or anaemia

Biochemistry panel

evaluates liver enzymes, bilirubin, and protein levels

Urinalysis

assesses urine concentration and hepatic urine changes

Abdominal ultrasound or radiograph

evaluates liver size and structural abnormalities

Advanced imaging (CT/MRI)

used when detailed assessment of blood flow or anatomy is needed

Liver biopsy (histopathology)

performed when tissue confirmation of microvascular dysplasia is required

04What happens after diagnosis? Medications, dietary changes & care guide

Management centres on dietary modification and supportive care. Regular monitoring of lab values and clinical signs is essential, with specialist referral considered as needed.

Switch to a low-protein or highly digestible prescription diet to reduce the burden on the liver
Supportive medications and symptomatic treatments as clinically indicated (at your vet's discretion)
Regular follow-up visits to monitor bloodwork and clinical signs
Imaging or biopsy arranged as needed based on test results
Ongoing home monitoring of bowel habits, energy levels, and body weight with record-keeping
Long-term follow-up at a clinic experienced in hepatic conditions is recommended

05What to prepare before the appointment — key information to help your vet

Bring a written log of when symptoms started, how they change daily, and any worsening

List recent diet, feeding routine, and any dietary changes

Record frequency and appearance of stools, with photos or videos if possible

Bring a complete list of all current medications, supplements, and prescription foods

If you have previous blood test results or imaging reports, bring them along

Consider calling ahead to book an appointment at a clinic with hepatic disease experience

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.

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Diarrhea

Loose stool