Fitness for fighter flying in a resolved case of neurocysticercosis: Dilemma in aeromedical disposition

Abstract

Neurocysticercosis (NCC) is the most common helminthic infection of the human central nervous system, and it’s the leading cause of acquired epilepsy worldwide. The clinical manifestations vary depending on the location, cyst stage, and host immune response. Seizure is the most common clinical presentation, but many patients present with focal deficits, intracranial hypertension, or cognitive decline. Neuroimaging is the mainstay of diagnosis. Cysticidal treatment, along with steroids, has shown increased and faster resolution of lesions. Seizure responds well to a single antiepileptic drug, and its recurrence rate is low with single lesions. Multiple and calcified lesions have recurrent seizures and require AED for a longer duration. Aeromedical concerns of the disease include the occurrence of any neurologic or cognitive symptoms and signs, and AED can have a CNS depressant effect. An in-flight seizure can cause unsustainable aircraft attitude, accidentally altering controls or engaging weapon systems and compromising flight safety. A 33 year old fighter aircrew of IAF with a flying experience of approximately 950 hours had an episode of generalized tonic clonic seizure. His MRI Brain revealed a ring-enhancing lesion in the left inferior temporal gyrus (<20mm) and was diagnosed as a case of Neurocysticercosis (Parenchymal NCC). He was managed conservatively with cysticidal therapy along with steroids and AED. During his follow up after six months, his CECT Brain revealed no residual lesions, and he was advised to stop AED. He has been observed adequately in the non-flying medical category for a period exceeding one year post stoppage of AEDs without seizure recurrence. Now, he was upgraded to the restricted flying category for another one year of observation before considering him for awarding the full flying category. The aeromedical concern in a case of Neurocysticercosis with seizure is a risk of sudden in-flight incapacitation due to seizure. In military/civil flying, the aircrew can be considered for unrestricted flying category for transport and helicopters. In this case, the aircrew had only a single episode of seizure, which was his presenting symptom, and had complete resolution of the brain lesion. However, after careful deliberation and consideration of all aeromedical concerns the decision was taken to reflight the aircrew in fighter flying with restriction.