<p> Online Resources</p><p>Table 1. Hospital and IFS cases: Demographics, clinical, and radiological features.</p><p>Case1 Age Sex Associated conditions Presenting Days of Neurological CT/MRI signs/symptoms hospitalization/ signs/symptoms (Yr) illness2</p><p>1 53 F Chronic obstructive Fever, shortness of 13 - - pulmonary disease breath (COPD), asthma, renal failure</p><p>2 16 M Asthma, Arnold Chiari Fever, respiratory 10 - - malformation type I distress</p><p>3 19 M Repaired tetralogy of Respiratory 24 - - Fallot, congenital distress absence of left kidney</p><p>4 14 F Pulmonary hypoplasia, Fever, respiratory 19 - - pneumonectomy distress</p><p>5 3 F Bronchopulmonary Fever, vomiting 7 Seizures (day 1 of Cerebral dysplasia hospitalization) edema (CT)</p><p>6 0.5 F - Fever, cough, 21 Hemiplegia (day 20 Cerebral diarrhea of hospitalization) hemorr- hage</p><p>7 20 F Interstitial lung disease Fever, cough, 7 - - respiratory distress, diarrhea</p><p>8 27 M Obesity - 14 - -</p><p>9 26 M Obesity - 6 - -</p><p>10 26 M Obesity, seizure - 14 Unwitnessed - disorder seizures </p><p>11 27 M Obesity, Myasthenia - 5 - - gravis </p><p>12 43 M Obesity - 8 Slurred speech -</p><p>13 54 M Obesity - 7 - -</p><p>14 0.5 M - - 21 - -</p><p>15 34 M Obesity, ventricular - 6 - - septal defect (VSD), patent ductus arteriosus (PDA)</p><p>1Cases 1 through 7 are hospital cases; 8 through 15 are IFS cases; 2Days of hospitalization for hospital cases; days of illness for IFS cases. MATERIALS AND METHODS</p><p>A retrospective study was performed of the autopsy brains of fatal, laboratory-confirmed, novel influenza A (H1N1) infection patients from institutions within the Texas Medical Center (TMC, Houston, </p><p>TX) in 2009. Our cohort consisted of seven cases admitted to various hospitals within the Texas Medical </p><p>Center (Texas Children’s Hospital, The Methodist Hospital, and Ben Taub General Hospital) and eight autopsies performed at the Harris County Institute of Forensic Science (IFS, formerly the Harris County </p><p>Medical Examiner’s Office). Diagnosis for swine-origin H1N1 was confirmed by RT-PCR on nasopharyngeal secretions (hospital cases) and lung tissue (IFS cases) according to CDC guidelines </p><p>{National Center for Health Statistics, 2009 #28}. </p><p>In all hospital cases and two of the IFS cases, gross examination was performed by a neuropathologist and standard neuropathologic sections (cortex, deep grey, hippocampus, brainstem, and spinal cord) were submitted. Gross examinations in the remaining six IFS cases were performed by the forensic pathologists performing the autopsy and two sections (cortex and hippocampus) were submitted in each case. The slides were reviewed by a neuropathologist. The HLA-DR immunostain and special stains (Luxol Fast Blue and Periodic Acid Schiff, LFB-PAS) were performed in the Histology </p><p>Laboratory of The Methodist Hospital using standard laboratory procedures. The available clinical, radiological, and laboratory data were retrieved from the medical records of the treatment hospital. </p><p>This exempt protocol was approved by The Methodist Hospital’s Institutional Review Board (Protocol # </p><p>IRB0807-0138).</p>