Heinz Body Hemolytic Anemia in Cats

What is Heinz body anemia?

Heinz body anemia is a type of anemia (reduced number of oxygen-carrying red blood cells) characterised by the presence of Heinz bodies (HB) on the red blood cell which leads to its destruction (known as hemolysis).

Cats are at greater risk of Heinz body anemia than other animals. Heinz bodies form when red blood cells are exposed to oxidative agents which cause changes (denaturation) to the hemoglobin chains within the red blood cells. Macrophages (a type of white blood cell) clear affected red blood cells in the spleen.

Methemoglobinemia is a second type of oxidative damage which can occur due to the presence of methemoglobin (an abnormal form of hemoglobin) in the blood. Methemoglobin can not bind to oxygen, leading to decreased availability of oxygen to the tissues.

Types of anemia:

  • Blood loss
  • Non-regenerative
  • Regenerative

Anemia from blood loss can be external (from a wound for example) or internal bleeding.

Non-regenerative anemia is due to a decrease in the production of red blood cells in the bone marrow.

Regenerative occurs when red blood cell production is normal however they are destroyed faster than they can be made.

Heinz body anemia is a form of regenerative anemia, red blood cells are made however the immune system destroys them due to the formation of Heinz bodies.

Causes

There are a number of causes of Heinz body anemia which can affect cats. Most cases are due to the consumption of oxidising substances such as certain medications, toxins, and foods, some of which include:

  • Allium species (onion, garlic, leek, chives, spring onion). Baby foods are a common source of onion and garlic toxicity in cats
  • Acetaminophen (paracetamol)
  • Propylene glycol (found in many products including soaps, shampoos, baby wipes and many types of processed food, including some types of semi-moist cat food)
  • Phenacetin (painkiller)
  • Methylene blue (urinary analgesic)
  • Benzocaine (a local anesthetic)
  • Naphthalene (mothballs)
  • Vitamin K
  • Zinc

Systemic disorders can also lead to the formation of Heinz bodies, including:

Clinical signs

Heinz bodies appear within 24 hours of exposure to the agent, however, there can be a lag of up to several days between ingestion and onset of symptoms. Severity depends on the amount of oxidant consumed as well as the duration of exposure. Heinz bodies tend to be produced at a slower rate by diet and disease compared to ingestion of drugs.

  • Lethargy
  • Anorexia
  • Abdominal pain
  • Yellow tinged membranes if jaundice is present
  • Tachypnea (rapid breathing)
  • Increased heart rate
  • Red or brown urine and cyanotic (blue/grey tinged) or brown membranes if methemoglobinemia is present
  • Hypersalivation
  • Weakness
  • Gastrointestinal disturbances such as abdominal pain, diarrhea, and vomiting.

We lost a kitten to this condition several years ago and his main symptoms were lethargy (the day before we realised he was sick), yellow gums (jaundice) and collapse.

If the underlying cause is due to systemic disease, there may be additional symptoms.

  • Diabetes: Increased thirst and urination, weight loss, weakness in the hind legs, bad breath.
  • Hyperthyroidism: Increased appetite, weight loss, jittery behaviour, rapid heartbeat.
  • Lymphoma: Symptoms can vary depending on the location but may include enlarged lymph nodes, anorexia, weight loss, and fever.

Diagnosis

The veterinarian will perform a complete physical examination of your cat and obtain a medical history from you including recent foods your cat may have eaten, medications or other household products he may have had exposure to.

Diagnostic workup:

  • Baseline tests: Biochemical profile to evaluate organ function, complete blood count and urinalysis. CBC may reveal a reduced number of red blood cells, additional findings may vary depending on the underlying cause.
  • Blood smear: Detection of Heinz bodies in blood smears stained with methylene blue. Note: Cats can have Heinz bodies in their red blood cells without having anemia.
  • Abdominal radiographs to look for metal objects if zinc toxicity is suspected.

If Heinz bodies are found but your cat has no history of ingestion (food, toxin, drug) it will be necessary for your veterinarian to look for an underlying cause such as systemic disease, in which case additional diagnostics will be necessary.

  • Diabetes: Blood and urine tests to look for high levels of glucose (hyperglycemia and glucosuria).
  • Hyperthyroidism: Blood tests to check levels of T3 and T4 hormone in the blood.
  • Lymphoma: Chest and abdominal radiography to look for thickening of the intestines or masses. Biopsy or fine needle aspirate may be taken from tissues and bone marrow.

Treatment

The goal of treatment is to address the underlying cause as well as supportive therapy.

Cats with severe anemia will be hospitalised and receive blood transfusions and oxygen therapy.

IV fluids therapy for cats who have severe vomiting and/or diarrhea and to protect the kidneys against hemoglobin-induced injury.

Follow up appointments will be necessary to assess red blood cell regeneration.

Prevention

  • Always read food labels carefully and avoid any products containing onion, garlic or members of the Allium family.
  • Dispose of food carefully.
  • Never administer medications unless your veterinarian has told you to do so. Cats are not small people or dogs and are unable to metabolise many medications.
  • Keep zinc-containing products locked away.
  • Avoid the use of mothballs in the home.
  • Don’t use lotions (such as sunscreen) containing zinc, which are easy to lick off.

In memory of Shadow.

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Julia Wilson is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. She enjoys photography, gardening and running in her spare time. Full author bio Contact Julia