# Major Complications Associated With Cerebrospinal Fluid Collection in 11 Dogs: Clinical Presentation and Imaging Characteristics

## TL;DR

This study reports on 11 dogs that experienced major complications after cerebrospinal fluid collection, highlighting the rare but severe risks involved.

## Contribution

The study provides the first detailed analysis of major complications from CSF collection in dogs at a single referral hospital.

## Key findings

- Major complications occurred in 0.15% of 7545 CSF collections.
- Eight dogs were euthanized due to severe complications like failure to recover spontaneous ventilation.
- MRI findings before CSF collection showed cerebral cortical swelling in many cases.

## Abstract

Cerebrospinal fluid (CSF) collection is routinely performed in dogs with neurological disorders. Little is known about the rate of major complications associated with CSF collection.

Determine the number of dogs experiencing a major complication secondary to CSF collection in a single referral hospital.

Eleven dogs.

Single‐center, retrospective description of the number and nature of major complications encountered during or after CSF collection in dogs.

From 7545 CSF collections performed between 1998 and 2024, 11 dogs (0.15%) experienced a major complication. Eight of these dogs had abnormal mentation on presentation. The most common neuroanatomical localization was multifocal (5/11). Nine dogs underwent magnetic resonance imaging (MRI) of the head and one dog had radiographs of the cervical vertebral column before CSF collection. The most common MRI findings included effacement of the cerebral sulci (7/9) and dilatation of the ventricular system (5/9). Cerebrospinal fluid collection was performed in 11 dogs, of which 3 were unsuccessful. Analysis of CSF aided in the diagnosis of meningoencephalitis of unknown origin (3/8), cryptococcosis (1/8), lymphoma (1/8), and results were normal in one and non‐specific in two dogs. Eight dogs were euthanized after failure to recover spontaneous ventilation (6), cardiopulmonary arrest (1) or severe neurological deterioration (1). One dog died during cardiopulmonary resuscitation. Repeat MRI after CSF collection identified caudal transtentorial and foramen magnum herniation in one dog. Two dogs survived to hospital discharge but with permanent neurological deficits.

The frequency of major complications following CSF collection was low, but the associated mortality was high. Abnormal mentation and MRI evidence of cerebral cortical swelling were commonly detected before CSF collection in dogs experiencing complications.