Diagnostic value of neuro-ophthalmological signs in cases of Chiari I malformation

Chiari Malformation Type I With Concurrent Bilateral Optic Disc Drusen: Is Follow-up Necessary?

Pseudopapilledema caused by optic disc drusen (ODD) mimics the appearance of papilledema and usually presents as a diagnostic challenge. A young boy with known Chiari malformation type 1 (CM-1) was referred to the pediatric ophthalmology clinic for eye assessment to exclude papilledema due to elevated intracranial pressure (ICP). Despite the ophthalmic examination revealing bilateral optic disc elevation, multimodal imaging techniques such as fundus autofluorescence, optical coherence tomography (OCT), and B-scan ultrasonography are recommended to confirm the distinction between bilateral ODD causing pseudopapilledema and papilledema secondary to elevated ICP. Accidental coexistent papilledema mimickers like ODD need to be considered in patients with CM-1 before making a diagnosis of papilledema to avoid unnecessary invasive procedures. There was no evidence that the presence of ODD excludes the possibility of future optic nerve head changes due to elevated ICP. The multidisciplinary consensus decided on annual ophthalmology follow-ups using multimodal imaging to detect any subtle optic nerve head changes.

Clinical diagnosis-part II: what is attributed to Chiari I

PURPOSE

Chiari malformation type I is identified as radiological appearance of cerebellar tonsil herniation below the foramen magnum. The wide spectrum of clinical manifestations variably associated sometimes encompasses signs and symptoms whose correlation with the malformation remains debatable. However, a correct clinical framework is relevant in tailoring the strategy of management, and in particular, establishing the appropriate surgical intervention.

METHODS

An analysis of relevant articles on this issue was performed, involving both single case reports and case series. The papers were obtained from electronic databases including PubMed/MEDLINE and Google Scholar, as well as direct contact with some authors.

RESULTS

This review focuses on those unusual clinical pictures attributed to Chiari malformation type I (CMI), investigating their actual relationship with the morphological condition. Supposed physiopathogenetic mechanisms and clinical relevance are discussed along with an analysis on the surgical indications and results.

CONCLUSION

There is no clear explanation on why some patients may exhibit uncommon symptoms, often in association with the most frequent ones, but even reported as single initial clinical occurrence. Their actual incidence may have been roughly underestimated in the literature so far, because of wide heterogeneity of selection and analysis among different studies. Most of the authors appear sharing the impression that CMI surgical decompression plays a significant role in controlling the majority of these unusual symptoms, stressing their actual occurrence in relation with the malformation. A routinely multidisciplinary clinical approach has become advisable to encompass the diversity of conditions potentially associated with CMI and improve the care of CMI patients.