Two RAMs and Half a Brain

Transcription

1 Two RAMs and Half a Brain J. Ron Allen, MD, MPH Lt Col, USAF, MC, SFS W. Javier Nieves, MD, MPH Lt Col, USAF, MC, FS USAF School of Aerospace Medicine WPAFB, OH RAM 2013 Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

2 Presenting History 42-yr-old right-handed male AGR C-130 flight engineer in the Air National Guard with 4200 total military flight hours, zero in the last 6 mo Aviator had been in his usual state of health until he started to feel a sensation of ear fullness and some mild confusion He initially attributed these symptoms to the onset of a cold Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

3 Presenting History Symptoms waxed and waned for a week until they intensified and he presented to the emergency room with headaches, confusion, ataxia and aphasia His evaluation included physical examination, computerized tomography imaging, magnetic resonance imaging (MRI), lumbar puncture with cerebrospinal fluid testing and electroencephalographic (EEG) testing Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

4 Neurologic Exam Peripheral pulses: full/symmetric; no carotid bruits Cervical spine: full ROM; no tenderness Head/scalp: normocephalic, nontender, head circumference 60.5 cm (above 90th percentile for height of 183 cm) Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

5 Neurologic Exam Mental status: MMSE 30/30, normal affect and mood Speech: clear, no dysarthria or aphasia noted Cranial nerves: II-XII normal bilaterally Sensory: normal light touch, pinprick, vibration sense bilaterally; no extinction noted Motor: normal bulk, tone, and strength bilaterally; no fasciculations observed Reflexes: 2+/4 diffusely; no pathologic reflexes noted, no ankle clonus noted Plantar response: flexor bilaterally Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

6 EEG/Consultations Routine EEG/sleep-deprived EEG study Mar 12: normal Neurosurgery consultation Oct 12: Differential Diagnosis: Aqueductal stenosis vs. Hydrocephalus: no hydrocephalus syndrome (slow progressive loss of mentation, gait disturbance or urinary incontinence) Pediatric neurology review and opinion Oct 12: also felt the condition was probably unrelated to the Feb 12 meningoencephalitis incident Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

7 Neuropsychiatric Testing 10 hours of testing: Estimate of premorbid baseline intellectual abilities was made with the AFQT * score, which was obtained approximately 20 yr ago, and estimated his IQ at 123 (superior range) Current intellectual test scores IQ 116 Reason, use judgment, and common sense were well within the normal range Verbal and visual attention and memory scores were variable in the extremely low range * Armed Forces Qualification Test Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

8 Hospital Course The hospital course was initially unremarkable. The patient was discharged after 4 days; 5 days later the patient relapsed and was readmitted for 4 days. He was discharged home, complete resolution of symptoms occurred over the next several weeks, and he subsequently completed a master's thesis in aeronautical science. Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

9 Neuroimaging Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

10 Neuroimaging Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

11 Diagnosis 1. Nonbacterial meningoencephalitis Feb 12, clinically resolved (6G ) 2. Severe communicating hydrocephalus, likely congenital due to aqueductal stenosis, normal CSF pressure, no clinical evidence of significant neurologic dysfunction (6G ) 3. Significant deficits noted in several areas of neuropsychological assessment, possibly related to diagnoses #1 and #2 (6G ) Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

12 Meningoencephalitis Aseptic meningitis (tissue surrounding the central nervous system) vs. meningoencephalitis (parenchyma involved) Any alteration of cognitive function, obtundation, focal neurological deficit, or complicated course is by definition aeromedically considered meningoencephalitis Diagnosis supported by: CSF with mild pleocytosis ( cell/mm 3 predominance of mononuclear or polymorphonuclear cells) Culture: normal-mildly elevated protein, normal-slightly depressed glucose Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

13 Meningoencephalitis Etiologies include: viral, bacterial, fungal, parasitic, neoplastic, vasculitic, and immune entities Viral etiology is the most common in U.S. more than all the others combined Common viral etiologies for encephalitis: H. simplex type 1 Arboviruses (St. Louis, Japanese encephalitis) West Nile Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

14 Aeromedical Concerns Acute: cognitive impairment, obtundation, focal neurological deficits, hemiparesis, and seizures Residual: neurocognitive impairment, movement disorders, and seizures Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

15 Standards Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

16 Standards U.S. Army: Army Regulation Standards of Medical Fitness Current or history of acute infectious processes of the central nervous system, including, but not limited to, meningitis (322), encephalitis (323), or brain abscess (324), are disqualifying if occurring within 1 year before examination, or if there are residual neurological defects. Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

17 Standards U.S. Navy: NAVMED Section IV Chapter 15 Encephalitis within the last 3 yr Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

18 Standards FAA CFR Neurologic. (1) Makes the person unable to safely perform the duties or exercise the privileges of the airman certificate applied for or held Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

19 Hydrocephalus "water in the brain" -- Greek words ὑδρο- (hydro-) "water", and κέφαλος (kephalos) "head" Described in 1000 AD by the Arab surgeon Abulcasis The skull of a newborn baby is often full of liquid, either because the matron has compressed it excessively or for other, unknown reasons What we know today Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

20 Hydrocephalus Excessive accumulation of cerebrospinal fluid (CSF) CSF originates in the choroid plexus (60-80%) and cerebral tissue Circulates through the ventricular system into the subarachnoid space Absorbed by the systemic venous circulation primarily across the arachnoid villi into the venous channels of the major sinuses Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

21 Hydrocephalus Excessive accumulation of cerebrospinal fluid (CSF) Most cases, this is caused by excess CSF accumulating in the cerebral ventricles due to disturbances of CSF circulation (known as obstructive or non-communicating hydrocephalus) Less often (communicating) and a result of decreased absorption Rarely is increased production Current thought is it s a combination of circulation and absorption Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

22 Hydrocephalus Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

23 Aeromedical Concerns Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

24 Hydrocephalus Excessive volume of CSF causes increased ventricular pressure and leads to ventricular dilatation In obstructive hydrocephalus, dilatation of the ventricular system occurs proximal to the obstruction Aqueductal stenosis causes dilation of the lateral and third ventricles Obstruction at the body of the lateral ventricle causes dilation of the distal temporal horn and atrium Obstruction of one foramen of Monro causes dilatation of the lateral ventricle on that side Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

25 Hydrocephalus Communicating hydrocephalus is dilation of the entire ventricular system, including the fourth ventricle Typically due to inflammation of the subarachnoid villi, but also may be caused by impaired CSF absorption Congenital Neural tube defects, intrauterine infections, CNS malformations, syndromic forms, etc. Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

26 Hydrocephalus Acquired Infections, tumors, and post-hemorrhagic/trauma Symptoms: result from increased intracranial pressure and dilatation of the ventricles and is dependent on how rapid the accumulation occurs If slow accumulation, the patient may have a long period without symptoms Rapid progression of ventricular dilatation typically results in early development of symptoms Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

27 Hydrocephalus Signs and symptoms: Macrocephaly Papilledema Extraocular muscle pareses leading to diplopia Pressure on the midbrain may result in impairment of upward gaze, spasticity of the extremities, cognitive deficits, seizures NOTE: all significant in aeromedical decision process Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

28 Hydrocephalus DX/TX MRI imaging of choice Third ventriculostomy, shunt placement, serial LPs Treatment dependent on location, type, progression of symptoms Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

29 Hydrocephalus Aeromedical Concerns Cognitive impairment, treatment complications (overdrainage, infection, mechanical failure), neurological impact, seizures all obviously play a role in decision making What is the baseline and what is the likelihood of progression? Risk of developing symptoms and the impact in regard to the big three : personal safety, mission safety, and mission accomplishment Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

30 Hydrocephalus Aeromedical Concerns Incapacitation? Subtle performance decrement? Remain stable? In the aviation environment? Easily detectable? Frequency of monitoring? Austere environments? Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

31 Standards U.S. Air Force: History or evidence of such defects as basilar invagination, hydrocephalus, premature closure of the cranial sutures, meningocele, and cerebral or cerebellar agenesis, if there is evidence of impairment of normal functions, or if the process is expected to be progressive NO WAIVER GUIDE 4 previous cases, 3 waivers granted; DQ IFC I with multiple issues Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

32 Standards U.S. Army: Army Regulation Standards of Medical Fitness 2 26 Neurological disorder history of congenital or acquired anomalies of the central nervous system (742) is disqualifying Flight Surgeon s Aeromedical Checklists No mention of hydrocephalus U.S. Navy: NAVMED Chapter History of congenital or acquired anomalies of the central nervous system is disqualifying Waiver guide does not mention hydrocephalus Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

33 Standards FAA: CFR Neurologic (1) Makes the person unable to safely perform the duties or exercise the privileges of the airman certificate applied for or held Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May

34 Questions? Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW , 3 May