Hepatic microvascular dysplasia

Hepatic microvascular dysplasia (HMD or MVD) or Portal Atresia is a disorder where mixing of venous blood and arterial blood in the liver occurs at the microscopic level. It occurs most commonly in certain dog breeds such as the Cairn and Yorkshire terriers although any dog breed may be at risk.

References

[JAVMA]

This disease impacts cats as well as certain breeds of dogs. It is sometimes mis-diagnosed as PSVA (Portosystemic Vascular Anomaly) or a "Liver Shunt". This affliction can be diagnosed with an MRI using a tracing dye in the subject's blood, and observing the flow of blood through the subject's liver and surrounding areas (stomach, intestine) for anomalies. It can also be indicated through a bile-acid level test; or more accurately, a "fasting-blood ammonia levels" test. Symptoms are concurrent with PVSA; stunted growth of subject in first 6-9 months, vomiting, seizures, and hydro-encephalitic episodes (from ammonia concentrating in the subject's blood). It is usually treated non-surgically with antibiotics (metronidazole) and stool-softeners (Lactulose). For causes and further information, refer to "Portosystemic_Shunt" in Wikipedia.