International Journal of Science and Research (IJSR) ISSN: 2319-7064 Index Copernicus Value (2016): 79.57 | Impact Factor (2018): 7.426 Volume 8 Issue 1, January 2019 www.ijsr.net Licensed Under Creative Commons Attribution CC BY Chronic Subdural Haematoma: Aeromedical Disposition Dr Ajay Kumar * , Dr Rahul Pipraiya +* *MBBS, MD, Assistant Professor (Aerospace Medicine), Institute of Aerospace Medicine, IAF, Vimanapura Post, Bangalore-17, India E –mail: ajay4757giri[at]gmail.com **MBBS, MD, Professor (Aerospace Medicine), Dean and CI, Institute of Aerospace Medicine, IAF, Vimanapura Post, Bangalore-17, India Abstract: Traumatic closed head injury and subsequent subdural lesions like chronic subdural hematoma (CSDH) carry a high risk of recurrence and post- traumatic seizure (PTS). This is particularly significant for an aircrew as sudden incapacitation due to inflight seizure can have disastrous consequences. This article reviews various policies and aeromedical consideration on chronic subdural hematoma for determining fitness of an aircrew for flying in civil and military aviation. Keywords: Chronic Subdural Haematoma, Aeromedical, Aviation, Disposition 1. Case History 55 yrs old civil helicopter pilot with 3485 hrs of flying experience reported at Medical Evaluation Centre at Institute of Aerospace Medicine IAF for renewal class – I medical assessment. Upon review of his medical history, the pilot revealed that he had sustained multiple musculoskeletal injuries (compression fracture L 1 , Multiple fracture transverse process D 11 - L 3 , undisplaced hairline fracture iliac bone, friction burn left arm and forearm with Radial nerve palsy) following crash landing in Aug 2012 for which he was managed at a military super-speciality hospital. According to first responders, he had questionable loss of consciousness (LoC), but was definitely mildly lethargic, which cleared over the course of his visit to local emergency department following crash landing. He was airlifted to Army Hospital (R&R) for further evaluation and treatment. He was alert during transfer without further alteration of consciousness, and his total alteration of consciousness was estimated to be greater than one hour but less than 24 hours. He appeared to have retrograde amnesia, initially not recalling the event. The time course of his amnesia was not clear but appeared to be concurrent with the period of alteration of consciousness. GCS score was 12/15. He was discharged after 03 weeks of institutional treatment. His hospital records revealed that a month of initial treatment he reported back to the Hospital with headache. On evaluation he was diagnosed to have chronic Subdural Hematoma (SDH). He underwent craniotomy for removal of haematoma (burr-hole evacuation). Post-op period was essentially uneventful. Past medical, personal and family history were not contributory. There was no history of any medication. He was evaluated at Air Force Central Medical Establishment (AFCME) in Nov 12 for Class-I Medical Assessment and was assessed temporary unfit for duration of 04 weeks. At the end of this period he reported to IAM IAF for fitness for Commercial Helicopter Pilot License (CHPL). 2. Chronic Subdural Hematoma Subdural lesions occurring after trauma is typically classified into - Acute Subdural Hematoma (ASDH), Chronic Subdural Hematoma (CSDH) and Subdural Hygroma (SDG). It is postulated that CSDH usually develop from ASDH and SDG, mostly SDG (1). Although etiology and location of these lesions are common, they have quite different clinical and radiological features. It is postulated that slow leakage of blood in subdural space from a tom bridge vein cause CSDH in aged and alcoholics due to cortical atrophy. SDG is believed to develop when there’s sufficient subdural space (subdural space is not present in normal condition) produced by any pathological condition (even minute trauma can separate dura- arachnoid space) leading to cleavage of tissue within the dural border cell layer which induce proliferation of dural border cells layer with production of neomembrane. Once neomembrane is formed, hyperpermeable capillaries follow with time. If the absorption takes time, hemorrhage into the subdural fluid would occur either by tearing of bridge veins or bleeding from neomembrane. The majority of SDG are asymptomatic and most SDG will disappear when the brain expansion or absorption exceeds effusion (1). CSDH differs from SDG in many aspects, such as the contents of subdural fluid, radiological appearance and clinical symptoms. However, an absolute distinction between SDG’s and CSDHs is often difficult, since the subdural fluid within SDG is frequently a mixture of blood and CSF. Paper ID: ART20194569 10.21275/ART20194569 1228