Terry M. Norton, DVM, DACZM
A high percentage of sea turtles present to the Georgia Sea Turtle Center (GSTC) with neurological signs. Causes of neurological disease in sea turtles include infectious disease, parasites, marine algal toxins, vascular insults, hypoxia, nutritional, metabolic, and space-occupying masses. The most common problem causing neurological disease, however, is traumatic injuries. Neurodiagnostics used in sea turtles include a neurological examination, clinical pathology and infectious disease testing, radiographs, advanced imaging, electromyogram, electroencephalogram, and cerebral spinal fluid tap.
A standardized neurological examination has been established for the sea turtles, which plays an important role in localizing lesions, prognostication, and evaluating the effectiveness of therapy. Turtles with neurological disease may exhibit circling, asymmetric buoyancy, inability to hold their heads up, ataxia, weakness, and paresis or paralysis. Sea turtles have 12 cranial nerves that are assessed in the same way a mammalian species is evaluated. Central nervous system signs include seizures, tremors, head tilt, visual deficits, and cranial nerve deficits. Ataxia and circling, nystagmus, head tilt, rolling, and imbalance are all signs of vestibular disease. Localizing spinal cord lesions is very similar to mammals. Complications of traumatic injuries involving the brain or spinal cord may include gastrointestinal ileus, osteomyelitis, and urinary bladder atony.
Therapeutic management of neurologic disease may include fluid therapy to achieve euvolemia or mild hypervolemia to avoid hypotension, oxygen therapy to avoid hypoxia, osmotic diuretics given IV via intermittent bolus, pain management, wound management, and antimicrobials. Complete healing and return to normal function may take 1–3 years in some cases.