Hemochromatosis and Iron Overload: Causes, Diagnosis, Clinical Presentation and Management

Introduction:

Hemochromatosis is a birth defect in which there is a mutation of the HFE gene. The condition causes increased iron absorption irrespective of intake. Hence, more iron gets accumulated, and iron storage increases. If the condition progresses, then iron gets deposited in other organs apart from bone marrow like in the liver, spleen, myocardium, joints, testes, and skin. Men are more commonly affected with hemochromatosis than women at a ratio of 3:1.

What Causes Hemochromatosis?

Iron overload can be congenital or acquired. Hereditary hemochromatosis is most common and follows the autosomal recessive pattern of inheritance (copies of the gene required from both the parents for the presence of disease). Depending on the gene mutation, hereditary hemochromatosis can be of four types

Type 1: HFE gene mutation - This type is considered the classic form of hemochromatosis and the condition occurs in a moderate form in adults. They occur with worldwide prevalence.

Type 2: Hemojuveline gene mutation in type 2a and hepcidin gene mutation in type 2b - Children are more affected by type 2 hemochromatosis and the disease is severe.

Type 3: Transferrin receptor-2 gene mutation - The onset is usually in young adults.

Type 4: Ferroportin gene mutation - Adult form.

Some of the acquired causes are,

• Ineffective erythropoiesis like in the case of thalassemia, megaloblastic anemia, and sideroblastic anemia.

• Alcoholic cirrhosis.

• Blood transfusion.

• Anemia of chronic disease.

• Atransferinemia.

• Hemolytic conditions.

• Drinking beer prepared in steel drums.

How Does Hemochromatosis Develop?

In hemochromatosis, excess iron gets deposited in parenchymal cells (functional cells of an organ), and in other cases, iron gets deposited in macrophages and reticuloendothelial cells (both are descendants of white blood cells). The overloading of iron can happen in three ways,

• Huge intake of iron orally.

• Increased iron absorption in spite of normal iron intake.

• Elevated production or transfusion of erythrocytes (red blood cells).

In different organs, excess iron gets deposited and leads to cell injury by two mechanisms:

Free Radical Formation: Hemosiderin (a deposited form of iron) in excess is highly toxic to the tissues and can induce oxidative stress.

Lysosomal Breakage: This process leads to the release of hydrolytic enzymes and rupture of cell wall resulting in cell death.

What Are the Symptoms of Hemochromatosis?

Initially, the patients may complain of joint pain, fatigue, and tiredness. Late symptoms of iron deposition are as follows:

Cutaneous: Skin pigmentation (iron and melanin deposition) and koilonychia (spoon-shaped nails) mainly affect the thumb and the index fingers.

Heart: Cardiomyopathy with electro cardio abnormalities leading to heart failure.

Liver: Hepatitis (liver inflammation) and cirrhosis is the most common and serious manifestation. Jaundice may be present in a few cases. There is also a risk of developing liver cancer.

Spleen: Splenomegaly (enlarged spleen).

Pancreas: Diabetes mellitus due to iron deposition in the pancreas. The incidence is around 50 percent. Since both skin pigmentation and diabetes are presented, hemochromatosis is also called bronze diabetes.

Bones: Osteoporosis (brittle bones).

Joints: Arthropathy (joint disease and pain) commonly affects the knees, wrists, hips, and back. Calcium pyrophosphate crystals are identified in synovial fluid (thick fluid in the joint space that reduces friction during movements).

Testes: Hypogonadism and testicular atrophy. The condition may be similar to degenerative joint disease.

Endocrinal Issues: Abnormal functioning of pancreatic, thyroid, parathyroid and adrenal glands.

How To Diagnose Hemochromatosis?

Diagnosis of hemochromatosis starts with the evaluation of all organs like the liver, heart, skin, and joints.

• Liver biopsy is the most sensitive and specific test to diagnose hemochromatosis, especially in the case of increased liver enzymes and serum ferritin levels.

• Bone marrow biopsy (in the biopsy of these two organs, iron deposition is seen as golden brown deposits).

• Serum ferritin increased as it reflects iron store.

• Transferrin saturation increased.

• Blood sugar level evaluation for patients with diabetes.

• Cardiac (electrocardiography - ECG) and joint evaluation.

• Genetic testing. Immediate family members are advised to undergo screening tests.

• Radiography to check heart (cardiomegaly) and lung involvement (vascular abnormalities). MRI (magnetic resonance imaging) may be useful in measuring the iron content in the liver.

How to Treat Hemochromatosis?

Phlebotomy:

Phlebotomy is a traditional way of managing hemochromatosis. 500 ml of blood has to be removed once or twice a week in hemochromatosis. 500 ml of blood contains 200 to 250 mg of iron which gets removed during each procedure.

The duration of congenital hemochromatosis usually includes one to two years. The aim of phlebotomy is to bring down serum ferritin levels below 50 ug/L. After achievement of this level, maintenance phlebotomy is done once in three months.

With phlebotomy, serum ferritin levels decline quickly, but transferrin saturation levels are decreased slowly. This procedure will gradually reduce skin pigmentation, fatigue, and insulin sensitivity but liver cirrhosis and arthropathy persist without any improvements.

Iron Chelation:

It can be given intravenously, subcutaneously, or orally. Deferiprone or Deferoxamine are some of the iron chelators. It removes only 10 to 25 mg of iron per procedure. So, it is not as effective as phlebotomy.

But in anemic patients, thalassemia, and hypoproteinemia patients, phlebotomy is not done, and so iron chelators need to be given.

Others:

Erythropoietin replacement may be sometimes required to maintain hemoglobin and consistent oxygen supply.

Liver transplantation in case of end-stage liver disease caused by iron overload. But the survival rate is low.

Since liver cancer is a common cause of fatality in hemochromatosis, patients should be kept under surveillance every six months.

What Are the Complications of Hemochromatosis?

Patients with untreated hemochromatosis will get the following complications.

• Liver cirrhosis (especially when associated with alcohol use).

• Liver cancer.

• Diabetes mellitus.

• Osteoporosis (brittle bones).

• Hypogonadism (insufficient hormone production).

• Heart failure.

• Increased possibility of acquiring infection from Yersinia enterocolitica.

Conclusion:

Hemochromatosis can be dangerous. Patients must be aware of the fact that with phlebotomy and chelating agents, one could easily prevent the complications related to hemochromatosis. It is recommended to avoid alcohol and foods containing iron and vitamin C.

Hemochromatosis condition is managed by an interprofessional team of doctors consisting of gastroenterologists and hepatologists. There may be a need to consult orthopedics and cardiology if the complications arise from hemochromatosis affecting joints and the heart.