Acute Neurological Presentation in the Post-Hibernation Chelonian: Toward a Differential Diagnostic Framework

Practitioners who manage temperate chelonians routinely encounter tortoises presenting with abnormal neurological signs — head tilt, circling, ataxia, nystagmus, or flaccid weakness — in the days to weeks following emergence from hibernation. Post-hibernation anorexia (PHA) is well characterized in the veterinary literature as a distinct clinical entity with an established diagnostic and therapeutic pathway. By contrast, the overlapping but distinct presentation of acute post-hibernation neurological dysfunction has never been assembled into a single differential framework, despite each of its component causes having some independent documentation. This paper reviews the evidence for six proposed etiological categories — cold-induced central nervous system injury, testudinid herpesvirus (TeHV) reactivation, post-hibernation hypoglycemia, hypocalcemia, environmental toxicosis, and vascular/reperfusion injury — and proposes a structured diagnostic approach that a clinician or experienced keeper can apply at first presentation. The available evidence for each category ranges from single-institution case series and blood-chemistry seasonal studies to clinical-experience compilations, and is markedly weaker than the evidence base underlying PHA; this unevenness is made explicit throughout rather than presented as uniform. A substantial portion of the primary husbandry and case experience informing this presentation likely exists in German, Italian, and French veterinary and hobbyist literature that could not be captured by an English-language search. The framework is intended as a starting point for case-based data collection rather than a validated protocol.