What does agranulocytosis mean?
Agranulocytosis is a serious hematological condition marked by a drastic reduction — often a near-total absence — of granulocytes, the white blood cells that form the body's first line of defense against bacterial and fungal infections. It most commonly arises as an adverse reaction to medications such as clozapine, methimazole, or certain chemotherapy agents, though it can also result from radiation exposure, toxins, or bone marrow disorders. Clinically, it typically presents with sudden high fever, sore throat, and ulcerations of the mouth and throat, and it constitutes a medical emergency requiring prompt treatment, including discontinuation of any offending drug and, frequently, broad-spectrum antibiotics. The term derives from Greek roots meaning 'without' and 'granules,' referring to the microscopic appearance of the affected cells. Because of its severity, drugs known to carry this risk are subject to strict monitoring protocols, making agranulocytosis a key concept in both hematology and pharmacovigilance.
nounA medical condition in which the number of granulocytes (a type of white blood cell) in the blood falls to dangerously low levels, leaving the body highly vulnerable to severe bacterial and fungal infections.
- A hematological disorder characterized by a severe deficiency or complete absence of granulocytes in the blood, typically resulting in high fever, mouth ulcers, and overwhelming susceptibility to infection.
"The patient developed agranulocytosis after starting the new medication, requiring immediate hospitalization."
"Clozapine therapy requires regular blood monitoring because of its well-known risk of causing agranulocytosis."
"The hematologist diagnosed agranulocytosis after the patient presented with a high fever and severe throat infection despite having no obvious source of illness."
Rarely used; the singular form predominates even when discussing multiple cases, which are usually referred to individually.
"The registry recorded several agranulocytoses linked to the withdrawn compound."
A single course of certain common medications can wipe out the body's infection-fighting granulocytes almost entirely — a condition so dangerous that before antibiotics, drug-induced agranulocytosis was often fatal within days.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of agranulocytosis
The word agranulocytosis was formed in early twentieth-century medical literature from Greek elements: the prefix 'a-' meaning 'without' or 'absence of,' combined with 'granulocyte,' itself built from Latin 'granulum' (small grain) and Greek 'kytos' (hollow vessel, later 'cell'), plus '-osis,' a Greek-derived suffix denoting an abnormal condition. It entered English usage as physicians sought precise terminology for the newly recognized syndrome of extreme granulocyte depletion, particularly following reports of fatal reactions to early synthetic drugs such as aminopyrine in the 1920s and 1930s. It shares its morphological roots with related terms such as granulocyte, leukocytosis, and cytology.
Related word forms
How agranulocytosis is actually used
A strictly technical, formal medical term used almost exclusively in clinical, pharmacological, and scientific contexts; it would rarely appear in everyday conversation. It carries an inherently serious connotation, as the condition is potentially life-threatening. The plural 'agranulocytoses' exists but is seldom used outside specialist literature.
Easily confused with agranulocytosis
Neutropenia is a broader term for any low neutrophil count, whereas agranulocytosis refers to an extreme, near-total absence of granulocytes.
Leukopenia is a general reduction in all white blood cells, while agranulocytosis specifically concerns the loss of granulocytes.