Nodular regenerative hyperplasia

Definition

Nodular regenerative hyperplasia is a form of liver hyperplasia associated with portal hypertension.

Nodular regenerative hyperplasia

Alternate names

Miliary hepatocellular adenomatosis; Non-cirrhotic nodulation; Non-cirrhotic nodular transformation; See More

Clinical features

Nodular regenerative hyperplasia (NRH) is a rare liver disease in which normal liver tissue transforms into multiple, small clusters (nodules) of replicating liver cells (regenerating hepatocytes).

Demographics

It can develop in people of all ages but is more common in older adults.

Signs and symptoms

NRH often does not cause signs or symptoms (so is likely underdiagnosed), but in some people, it leads to a type of portal hypertension called non-cirrhotic portal hypertension (NCPH).

Portal hypertension

NCPH refers to abnormally high blood pressure in the portal vein (the vein that carries blood from the intestine to the liver) that is not caused by cirrhosis (scarring of liver tissue that impairs its function). NCPH typically is less severe than portal hypertension caused by cirrhosis.

Symptoms of portal hypertension may include fatigue, edema, itching, jaundice, and abdominal discomfort or swelling due to fluid build-up (ascites)<ref><ref>Hartleb, Marek,

 Nodular regenerative hyperplasia: Evolving concepts on underdiagnosed cause of portal hypertension, 
 World Journal of Gastroenterology, 
 
 Vol. 17(Issue: 11),
 pp. 1400–1409,
 DOI: 10.3748/wjg.v17.i11.1400,
 PMID: 21472097,
 PMC: 3070012,</ref></ref>. 

Complications

Complications that may develop include bleeding esophageal varices and an enlarged and overactive spleen (hypersplenism).

Tests

Liver function in most people with NRH remains normal (even in those who develop NCPH), and liver failure in people with NRH and NCPH is rare.[4][5]

Cause

The cause of NRH is not well-understood. It is thought that the liver’s blood vessels somehow become damaged or inflamed, impairing blood flow to parts of the liver. This in turn may cause cells in adjacent parts to “overcompensate” and replicate more than they should, leading to NRH.

Risk factors

While some people with NRH have no known underlying health problems, NRH is often associated with rheumatic, autoimmune, hematologic (blood-related), and myeloproliferative disorders; chronic or recurrent infections; immune deficiency; or exposure to certain medications or toxins.

Diagnosis

NRH may be diagnosed based on signs and symptoms (when present), liver function tests (which usually are normal), medical history (including drug or toxin exposure), imaging studies, and liver biopsy (to rule out cirrhosis). Accurate diagnosis is made by histopathology, which demonstrates diffuse micronodular transformation without fibrous septa. Lack of perinuclear collagen tissue distinguishes NRH from typical regenerative nodules in the cirrhotic liver.

Treatment

Treatment for people with NCPH may involve starting medications to prevent or treat bleeding esophageal varices, stopping medications associated with NCPH, and treating underlying health conditions associated with NCPH.

Prognosis

The long-term outlook for people with NRH depends on whether an underlying health problem is present and whether NCPH and its complications develop (which cannot be predicted).

Liver transplant

A small proportion of people eventually need a liver transplant.

References

ICD10: K76.8

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