Diffuse Axonal Injury: A Devastating Pathology

Traumatic brain injury (TBI) also known as intracranial injury is the result of a lesion within the brain due to an external force. Common forms of TBI result from falls, violence, and/or vehicle crashes; the classification of this pathology is dependent on the severity of the lesion as well as the mechanism of trauma to the head. One of the most common onsets of traumatic brain injuries result from mild to severe lesions to the white matter tracts of the brain called diffuse axonal injury (DAI); however, additional forms of TBI’s can present in non-penetrating forms. Penetrating forms of TBI’s such as trauma to the head via a foreign object do also contribute to the many millions of TBI cases per year, but we will not discuss these traumatic injuries as in depth within this chapter. The onset of diffuse axonal injury will vary on a per-patient basis from mild to severe, based on a standardized neurological examination rated on the Glasgow Coma Scale (GCS), which indicates the severity of brain damage present. While there is a spectrum of severity for DAI patients, a concussion is typically observed within a larger majority of patients in addition to other overwhelming trauma

Management of Intracranial Pressure in Traumatic Brain Injury

Traumatic brain injury (TBI) is the result of an external force acting upon the head, causing damage to the brain. The severity of injury, mechanism by which the injury occurs, and the frequency of the high-force impact all play a role in the determination of a TBI. TBI describes a wide range of traumatic pathologies which is comprised of damage done to a multitude of cranial central nervous system components. TBI patients typically present with a series of symptoms are correlated with the presence of an intracranial injury, such as physical/cognitive difficulties. A major concern associated with intracranial injuries is the management of intracranial pressure (ICP), a resulting factor of a TBI which facilitates into intracranial hematoma and/or cerebral edema. These conditions have adverse effects on one’s brain, and the immediate management and relief of intracranial pressure are crucial in avoiding hydrocephalus and brain herniation, conditions which lead to sensory loss and even death. In this chapter, we will begin by thoroughly understanding what a TBI is, its clinical presentation, and the first-tier examination to determine severity. Then, we will progress into the anatomy of the brain, followed by a thorough investigation into intracranial pressure management strategies and prognosis

Management Strategies and Outcomes for VHL-related Craniospinal Hemangioblastomas

Hemangioblastomas are rare and benign tumors accounting for less than 2% of all central nervous system (CNS) tumors. The vast majority of hemangioblastomas occur sporadically, whereas a small number of cases, especially in younger patients, are associated with Von Hippel–Lindau (VHL) syndrome. It is thought that loss of tumor suppressor function of the VHL gene results in stabilization of hypoxia-inducible factor alpha with downstream activation of cellular proliferative and angiogenic genes that promote tumorigenesis. VHL-related hemangioblastomas predominantly occur in the cerebellum and spine. Lesions are often diagnosed on contrast-enhanced craniospinal MRIs, and the diagnosis of VHL occurs through assessment for germline VHL mutations. Surgical resection remains the primary treatment modality for symptomatic or worrisome lesions, with excellent local control rates and neurological outcomes. Stereotactic radiotherapy can be employed in patients who are deemed high risk for surgery, have multiple lesions, or have non-resectable lesions. Given the tendency for development of either new or multiple lesions, close radiographic surveillance is often recommended for asymptomatic lesions

Intracranial Myeloid Sarcoma Metastasis Mimicking Acute Subdural Hematoma

Myeloid sarcoma, a rare consequence of myeloproliferative disorders, is rarely seen in the central nervous system, most commonly in the pediatric population. Although there are a handful of case reports detailing initial presentation of CNS myeloid sarcoma in the adult population, we have been unable to find any reports of CNS myeloid sarcoma presenting as a large mass lesion in a herniating patient. Here, we present the case of a patient transferred to our facility for a very large subdural hematoma. Based on imaging characteristics, it was felt to be a spontaneous hematoma secondary to coagulopathy. No coagulopathy was found. Interestingly, he did have a history of acute myeloid leukemia (AML) diagnosed 2 months previously, and intraoperatively he was found to have a confluent white mass invading both the subdural and subarachnoid spaces. There was minimal associated hemorrhage and final pathology showed myeloid sarcoma. This is the first report we are aware of in which CNS myeloid sarcoma presented as a subdural metastasis and also the first report in which we are aware of this etiology causing a herniation syndrome secondary to mass effect

Cognitive status predicts preoperative instruction compliance

The most common postoperative complication for older adults is perioperative neurocognitive disorder (PNCD). Its greatest risk factor is preoperative cognitive impairment. Cognitive impairment also predicts higher likelihood of postoperative complications. While the cause of disparity in outcomes is likely multifactorial, the ability to correctly follow perioperative instructions may be one modifiable component. The purpose of this study was to determine whether cognitive impairment led to reduced preoperative instruction compliance and if so, identify barriers and enact a tailored care-plan to close the gap. Our preoperative clinic implemented routine Mini-Cog screening to identify older (age ≥ 65) surgical patients at increased risk. All patients received the same instructions and, on day of surgery, were surveyed to determine correct execution of nil per os guidelines, chlorhexidine wipe use and medication management. Data was stratified by cognitive status to evaluate whether impairment predicted instruction execution. Feedback from patients and families were compiled. Of those who screened negative for impairment, 68% correctly followed instructions, while 84.2% of those impaired struggled with ≥1 instruction(s); impaired patients were more likely to incorrectly follow instructions (OR = 10.5, p-value = 0.001). Areas for change were identified and team-based solutions were enacted with additional support for those with impairment. We found a clear difference in correct execution with respect to cognitive status. By improving instructions as an institution and adding additional support for those with impairment, the compliance gap was significantly reduced. Targeting perioperative instructions and tailoring care in this population may be one modifiable component in the outcome disparity they face

Unusual Case of Metastatic Gastrointestinal Adenocarcinoma to the Cervical Spine without a Detectable Primary Source in a Patient with Acquired Immunodeficiency Syndrome: A Case Report

The authors report a case of metastatic gastrointestinal adenocarcinoma to the cervical spine in a patient with acquired immunodeficiency syndrome (AIDS) being treated with antiretroviral therapy. The source of this tumor could not be identified despite a thorough evaluation. A 49-year-old male being treated for AIDS presents with worsening neck pain and left distal arm weakness. MRI demonstrated an erosive mass within the cervical four vertebral body extending through the pedicle on the left side. Patient underwent needle biopsy followed by combined anterior and posterior fusion procedures. Pathology demonstrated metastatic gastrointestinal adenocarcinoma without known primary origin. He is currently undergoing palliative radiotherapy. This is an unusual case of metastatic gastrointestinal adenocarcinoma to the cervical spine. This should be included on the differential diagnosis of spinal lesions in this patient population and may represent a unique tumor in patients with HIV/AIDS who are on immunosuppressive therapy

Feeding Responses to Predator-Based Repellents in the Mountain Beaver (\u3ci\u3eAplodontia rufa\u3c/i\u3e)

Predator odors have potential as feeding repellents for mammalian herbivores, including Aplodontia rufa, the mountain beaver. However, the repellency of major chemical constituents of natural predator scents for this species has not been evaluated. In this study, the effects of several synthetic sulfur compounds from predator scents on feeding by mountain beavers were assessed and compared to the effects of coyote (Canis latrans) urine. Retrieval of food by mountain beavers from bowls scented with either coyote urine, diluted with water to different concentrations, synthetic components of predator scents, or control odorants was studied. The following synthetic compounds were tested: Δ3-Isopentenyl methyl sulfide (IMS), a compound present in urine from several canid species; 2,2 dimethylthietane (DMT), a major constituent in anal gland secretion from the mink (Mustela vison); a 1: 1 mixture of 2-propylthietane (PT) and 3-propyl-l,2-dithiolane (PDT), compounds occurring in anal gland secretions from the stoat (Mustela errninea) and the ferret (Mustela putorius). Habituation to PT plus PDT was studied by measuring consumption of dry pellets during continuous exposure to these compounds for 5 d. In two-choice feeding trials mountain beavers retrieved significantly more food from bowls scented with water than from bowls scented with coyote urine. Dilution of urine had no statistically significant effect on food retrieval, but repellency tended to decrease with decreasing concentration. Mountain beavers retrieved less food scented with a 1: 1 mixture of PT and PDT, compared to controls. However, they rapidly habituated to this mixture. None of the other compounds caused an avoidance response. These results show that complex natural predator scents are more effective feeding repellents than some of their major volatile components alone