Agranulocytosis
A dangerous shortage of infection-fighting white blood cells
Quick Facts
- Type: Blood and immune disorder
- Cell affected: Neutrophils (granulocytes)
- Common triggers: Certain medications, autoimmune disease
- Key danger: Severe, rapidly spreading infections
Overview
Agranulocytosis is a severe shortage of neutrophils, a type of white blood cell that forms a major part of the body's defense against bacteria and fungi. Neutrophils belong to a group called granulocytes. When their numbers fall very low, even minor infections can quickly become serious because the body cannot fight germs effectively.
Agranulocytosis can develop suddenly, often as a reaction to a medication, or more gradually from disease affecting the bone marrow where blood cells are made. Because the risk of dangerous infection is high, agranulocytosis is treated as a medical emergency when fever or signs of infection appear. With prompt recognition and care, many people recover, especially when a triggering drug is stopped.
Symptoms
Agranulocytosis itself may cause no symptoms until an infection takes hold. The first sign is often a sudden infection. Symptoms can include:
- Fever and chills
- Sore throat and mouth ulcers
- Feeling generally unwell, weak, or tired
- Rapid heartbeat and rapid breathing
- Signs of infection such as skin sores, pneumonia, or gum infection
A fever in someone known to have a very low white blood cell count is a medical emergency. It can signal an infection that may spread rapidly and needs urgent treatment.
Causes
Agranulocytosis happens either because neutrophils are destroyed or because the bone marrow does not make enough of them. Common causes include:
- Medications: A number of drugs can trigger it, including certain antithyroid medicines, some antibiotics, antipsychotics such as clozapine, and chemotherapy.
- Autoimmune disease: The immune system mistakenly attacks neutrophils.
- Bone marrow disorders: Conditions that crowd out or damage the marrow.
- Infections: Some severe viral or other infections.
- Inherited conditions: Rare genetic disorders present from birth.
Risk Factors
- Taking medications known to lower white blood cell counts, such as clozapine or certain antithyroid drugs
- Undergoing chemotherapy
- Having an autoimmune condition
- Bone marrow disease or a history of blood disorders
- Older age
Diagnosis
Agranulocytosis is identified through blood testing, often prompted by infection or routine monitoring of a high-risk medication:
- Complete blood count (CBC): Shows a very low neutrophil count.
- Blood differential: Measures the specific types of white blood cells.
- Bone marrow examination: Sometimes used to find out why the marrow is not producing enough cells.
- Cultures and infection tests: Blood, urine, and other samples to locate any infection.
A careful review of medications and recent illnesses helps identify the cause.
Treatment
Treatment focuses on protecting against infection, treating any infection present, and addressing the cause:
- Stopping the trigger: Any suspected medication is stopped if possible, which often allows counts to recover.
- Antibiotics: Started quickly, often through a vein, when fever or infection occurs.
- Growth factors: Medicines that stimulate the bone marrow to make more neutrophils may be used.
- Supportive care: Isolation measures and good hygiene to reduce exposure to germs while counts are low.
- Treating the underlying cause: Such as managing an autoimmune or marrow disorder.
Many people recover once the trigger is removed and infection is controlled.
Prevention
While not all cases can be prevented, several steps reduce risk and catch problems early:
- Regular blood monitoring when taking medications known to lower white blood cell counts
- Reporting fever, sore throat, or mouth sores promptly to your healthcare team
- Practicing good hand hygiene and avoiding people who are sick when counts are low
- Carrying information about high-risk medications so any provider is aware
- Keeping all scheduled blood tests during treatment
When to See a Doctor
If you take a medication known to lower white blood cells or are on chemotherapy, treat a fever as an emergency and seek care urgently. Get prompt medical attention for:
- Fever or chills
- Sore throat or painful mouth ulcers
- Signs of infection such as redness, swelling, or productive cough
- Feeling suddenly very unwell with rapid heartbeat or breathing
Frequently Asked Questions
What is agranulocytosis?
Agranulocytosis is a severe drop in neutrophils, the white blood cells that fight bacteria and fungi. With so few of these cells, the body cannot defend against germs, so infections can become serious quickly. It is often triggered by certain medications and is treated urgently when infection appears.
Why is a fever an emergency with agranulocytosis?
When neutrophils are very low, the body cannot contain infection, so even a small infection can spread rapidly and become life-threatening. A fever may be the only early clue that infection is taking hold. People with very low counts who develop fever should seek urgent medical care.
Which medications can cause agranulocytosis?
Several drugs can trigger it, including some antithyroid medicines, certain antibiotics, the antipsychotic clozapine, and chemotherapy agents. People on high-risk medications usually have regular blood tests to catch a falling count early. Stopping the trigger often allows recovery.
Can agranulocytosis be reversed?
In many cases, yes. When a medication is the cause, stopping it often lets neutrophil counts recover over days to weeks. Treatment also includes antibiotics for any infection and sometimes growth factors that stimulate the bone marrow. Recovery depends on the cause and prompt care.
How is agranulocytosis diagnosed?
It is found with a blood test called a complete blood count that shows a very low neutrophil level. Doctors review medications and recent illnesses to find the cause and may examine the bone marrow. Cultures help locate any infection that needs treatment.
References
- MedlinePlus, U.S. National Library of Medicine. Agranulocytosis.
- National Heart, Lung, and Blood Institute (NHLBI). Neutropenia.
- Merck Manual Consumer Version. Neutropenia.
- Cleveland Clinic. Agranulocytosis.