Discussion
Neoplastic meningitis continues to be diagnostically challenging due to its subtle, varied, and non-specific clinical features. This case illustrates an initial presentation of vertigo, with sub-acute progression to cerebral involvement and higher executive dysfunction. Headache remains the most common symptom of neoplastic meningitis (present in 66% of cases) but is non-specific. 50% present with myelopathy, with symptoms such as lower limb weakness, paraesthesia or bowel or bladder disturbance. 35% present with isolated or grouped cranial nerve palsies, and 15% present with cerebral dysfunction manifesting as higher cortical deficits such as confusion or dysphasia.5-6 In retrospect, it is likely that the initial dizziness in this case was related to an isolated 8th (vestibulocochlear) nerve palsy with branch involvement leading to vestibular neuronitis.
Treatment of neoplastic meningitis is palliative and although cannot reverse existing neurological deficits may prevent deterioration.7 Aggressive treatment can increase survival time from 4-6 weeks to 6 months,5-7highlighting the importance of early recognition and diagnosis. Clinicians must therefore be aware of the many manifestations and maintain a high index of suspicion.
With reference to diagnosis, a triad of factors including classical symptoms and signs, appropriate findings on MRI imaging, and CSF analysis should be used.5 MRI imaging is used to look for features of meningeal enhancement, whilst CSF findings of increased lymphocytes, high protein, very low CSF:serum glucose ratio, and high lactate, illustrated perfectly in this case, are highly suggestive of a diagnosis. 5-6 Positive cytology from CSF is gold standard although this cannot always be obtained and may require multiple, large volume LPs.5-6 This case exemplifies the important role an LP can play in investigating new neurological symptoms.
Lastly, this case provides us with the opportunity to reflect on reasons behind diagnostic error. The prevalence of, and harm, that can arise from diagnostic error is well documented in the literature8-9 and it is therefore important that, as clinicians, we reflect on our practice in order to understand the factors influencing our decision-making. This case offers a reminder of the particular challenge recurrent attenders present, and the bias that can arise from anchoring to an initial or previous diagnosis. This patient received a diagnosis of BPPV from a consultant neurologist and, despite changing clinical features on subsequent presentations, this diagnosis was maintained following review by three experienced general physicians. This highlights the importance of remaining open minded in such cases and recognising diagnostic bias that may exist.
List of Abbreviations
BPPV = Benign Paroxysmal Positional Vertigo
CSF = Cerebral Spinal Fluid
CT = Computed Tomography
LP = Lumbar puncture
MRI = Magnetic Resonance Imaging
Author Contributions
Author 1: Dr Catriona Davidson MBBS MRCP, CT2 Addenbrookes Hospital, catriona.davidson@nhs.net – Joint lead author
Author 2: Dr Katerina Achilleos BSc (Hons) MBBS MRCP, Consultant Rheumatologist West Suffolk Hospital, katerina.achilleos@wsh.nhs.uk – Joint lead author
Author 3: Dr Francesca Crawley MBBCh, FRCP, Consultant Neurologist West Suffolk Hospital, francesca.crawley@wsh.nhs.uk – Author
Author 4: Dr William Petchey BSc (Hons) BM PhD MRCP, Consultant Nephrologist West Suffolk Hospital, william.petchey@wsh.nhs.uk – Senior author