Leukocytic reaction in cytology

Leukocytic reaction in gynecological cytology

In inflammatory pelvic diseases, cytological examination of exudates and smears serves as an important diagnostic criterion. A characteristic example is endocervicitis — inflammation frequently associated with gonococci or Chlamydia.

During microscopy of cervical smears, the cytologist observes the following picture:

• Columnar and stratified squamous epithelial cells are present.
• There are no signs of cellular atypia (which helps rule out malignant processes).
• An inflammatory leukocytic reaction is clearly visualized.

Clinically, this process is accompanied by mucopurulent or purulent discharge, hyperemia, and mucosal edema around the external os. When the process becomes chronic (progressing to cervicitis), the muscular layer is involved in the inflammation, leading to cervical hypertrophy and the formation of Nabothian cysts (ovulae Nabothii).

If the infection spreads to the upper genital tract, acute endometritis develops (involvement of the functional and basal layers of the uterine mucosa). In this situation, the local leukocytic reaction turns into a systemic one: the complete blood count shows pronounced leukocytosis, lymphopenia, elevated ESR, and a left shift in the leukocyte formula. Ultrasound visualization reveals an indistinct boundary between the endometrium and myometrium, as well as an expanded uterine cavity with hypoechoic contents.

CSF cytology in neuroinfections

Assessment of the leukocytic reaction in cerebrospinal fluid (CSF) is the "gold standard" for diagnosing generalized nervous system infections. A classic example is meningococcal meningitis, in which lumbar puncture provides irrefutable evidence of the bacterial nature of the inflammation.

Cytological and laboratory characteristics of CSF in meningitis:

1. Macroscopy: the cerebrospinal fluid loses its transparency, becoming turbid and whitish; CSF pressure is elevated.
2. Cytology: massive neutrophilic pleocytosis is diagnosed. The cell count reaches 500–1,000 or more per 1 µL, with neutrophils accounting for 60% to 100% of the cell pool.
3. Bacterioscopy: against the background of accumulated leukocytes, Gram-negative diplococci are detected, which can be located both intracellularly (inside phagocytes) and extracellularly.
4. Biochemistry: cytoalbuminologic dissociation is observed (protein level increased up to 2–8 g/L with marked cytosis) along with a decreased glucose concentration.

It is important to note that CSF sampling for bacteriological culture and assessment of the leukocytic reaction must be performed before initiating antibacterial therapy.

Systemic leukocytic reaction in the hemogram

When an infectious process becomes generalized (e.g., in meningococcemia), the local cell reaction is replaced by severe changes in the peripheral blood as part of the systemic inflammatory response syndrome (SIRS).

Key hemogram changes:

• Neutrophilic hyperleukocytosis with a sharp left shift in the leukocyte formula.
• High erythrocyte sedimentation rate (ESR).
• Thrombocytopenia (as a manifestation of DIC) or, conversely, thrombocytosis against the background of acute bacterial inflammation.
• A significant increase in inflammatory markers: C-reactive protein (CRP) and procalcitonin (PCT).

Interestingly, the diagnosis of a generalized form of meningococcal infection can be established clinically solely on the basis of symptoms (acute onset, hemorrhagic rash) and a pronounced systemic leukocytic reaction in the blood, even if specific tests (culture or PCR) are negative due to pre-hospital antibiotic administration.

Class and exam questions

What else to study on this topic

• Pathogenesis and ultrasound diagnosis of acute endometritis
• Procedure and interpretation of lumbar puncture
• Molecular biological diagnostics (PCR) of neuroinfections
• Systemic inflammatory response syndrome (SIRS)
• Cytoalbuminologic dissociation in CSF analysis

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.