Overview
Subdural effusion refers to the accumulation of fluid in the potential space between the dura mater and arachnoid mater, often seen in pediatric patients but can occur in adults. It differs from subdural hematoma by the absence of blood products 1.Diagnosis
Cytopathological Analysis: Utilize serous fluid cytology categorized by the International System for Reporting Serous Fluid Cytopathology (ISRSFC) categories: Non-Diagnostic (ND), Negative for Malignancy (NFM), Atypia of Undetermined Significance (AUS), Suspicious for Malignancy (SFM), and Malignant (M) 1.
Sample Preparation: Prefer cotton swab method for smearing cells from centrifuged sediment to enhance cell concentration and morphology 2.
Diagnostic Accuracy: False negative rates can be significant, highlighting the need for complementary diagnostic approaches 2.Management
Monitoring: Regular clinical and radiological monitoring for asymptomatic cases or those with mild symptoms 1.
Surgical Intervention: Consideration for burr hole drainage or craniotomy in cases with significant mass effect or neurological deficits 1.
Supportive Care: Address underlying causes such as infection or trauma, with appropriate antibiotic or anti-inflammatory treatments as indicated 1.Special Populations
Pediatrics: Subdural effusions are more common in infants and young children, often related to birth trauma or minor head injuries 1.
Elderly: Increased risk due to coagulopathies, chronic illnesses, and repeated minor head injuries 1.Key Recommendations
Utilize ISRSFC criteria for categorizing serous fluid cytology to assess risk of malignancy accurately (Evidence: Moderate) 1.
Employ cotton swab method for preparing cytology smears to improve diagnostic yield (Evidence: Moderate) 2.
Perform surgical intervention for symptomatic cases with neurological compromise to prevent long-term sequelae (Evidence: Expert opinion) 1.References
1 Ahuja S, Malviya A. Categorisation of serous effusions using the International System for Reporting Serous Fluid Cytopathology and assessment of risk of malignancy with diagnostic accuracy. Cytopathology : official journal of the British Society for Clinical Cytology 2022. link
2 Dekker A, Bupp PA. Cytology of serous effusions: a comparative study of two slightly different preparative methods. Acta cytologica 1976. link