Case 1 Imaging. (a, b) Pretreatment axial and coronal T1 post-contrast MRIs demonstrate a ring-enhancing intra-axial mass with central necrosis. (c) Pretreatment axial FLAIR MRI demonstrates surrounding vasogenic edema that was managed with corticosteroids. (d) Posttreatment axial FLAIR MRI demonstrates a significant increase in vasogenic edema, which is now diffuse and encompasses the majority of the right cerebral hemisphere
According to Central Brain Tumor Registry of the United States, the annual incidence of primary CNS tumors is 22.36 cases per 100,000 people. Thus, it is estimated that there will be ~79,270 new cases of primary CNS tumors diagnosed in the United States (USA) in 2017. This includes both malignant (~26,070 new cases) and benign (~53,200 new cases) pathologies. The most common malignant primary CNS tumor is glioblastoma (GBM), a highly aggressive type of glioma that arises from glial cells. The most common benign primary CNS tumor is a meningioma, which arises from the arachnoid cap cells of the meninges. In the United States, ~17,000 deaths will be attributed to primary malignant CNS tumors in 2017 .
Metastatic CNS neoplasms are much more common than primary CNS neoplasms. It is estimated that 100,000 new cases of metastatic brain tumors are diagnosed in the United States each year. Furthermore, approximately 20–40% of cancer patients will develop brain metastases at some point in their disease course. The most common cancers to metastasize to the brain include lung, breast, and melanoma .
Patients with brain tumors present to medical attention with a wide variety of signs and symptoms, depending on the size and location of the tumor. Tumors in relatively ineloquent locations (i.e., right frontal pole) often grow to a large size and present with generalized signs of mass effect such as headache, nausea/vomiting, and fatigue. In contrast, tumors in highly eloquent locations (i.e., left frontal operculum) may present at a much smaller size by causing focal neurologic deficits. Brain tumor patients also commonly present with seizures, vision changes, cognitive decline, sensory or motor deficits, and ataxia.
In general, treatments for brain tumor patients are directed toward two synergistic goals: improvement of neurologic function and improvement of oncologic outcome. These treatments can include surgical resection, chemotherapy, radiation, and medical management. Benign tumors are most often treated with surgical resection alone, although radiation may be required for surgically inaccessible skull base tumors. Malignant tumors most often require a combination of surgical resection, chemotherapy, and radiation. In this chapter, we will focus our attention on reviewing the management of common critical care issues that occur in brain tumor patients.
14.2 Case Presentations
14.2.1 Case 1
Thirty-eight-year-old right-handed male presents to medical attention with a rapidly progressive left hemiparesis. Intracranial imaging revealed a right frontal, intra-axial, enhancing mass lesion within the subcortical motor pathway (Fig. 14.1a–c). The patient was started on high-dose dexamethasone (10 mg initial bolus, followed by 4 mg every 6 h) and noted to have improvements in his motor exam the next day. Due to the location of the lesion, a stereotactic biopsy was performed; pathology revealed a glioblastoma. The patient was subsequently treated with adjuvant chemotherapy (temozolomide) and radiation, and steroids were slowly tapered.
Approximately 3 weeks later, the patient presented to medical attention with headache, lethargy, nausea/vomiting, and increased left-sided weakness. Repeat intracranial imaging revealed a significant increase in peritumoral edema with new mass effect, midline shift, and early obstructive hydrocephalus (Fig. 14.1d). The patient was admitted to the ICU and started on high-dose IV dexamethasone as well as hyperosmolar therapy (3% saline and mannitol). Within 12 h, he reported improvements in his headaches and had objective improvements in his left-sided strength. He was then started on bevacizumab, with resolution of his headaches. He subsequently resumed his combined chemotherapy and radiation therapy 2 weeks after admission.
14.2.2 Case 2
Sixty-one-year-old right-handed female presents to medical attention after experiencing a generalized tonic-clonic seizure at work. Intracranial imaging revealed a large, en plaque right frontal meningioma with hyperostosis of the overlying calvarium (Fig. 14.2a, b). She was started on levetiracetam and taken to the operating room several weeks later for elective surgical resection (Fig. 14.2c, d).
Case 2 Imaging. (a, b) Preoperative axial and sagittal T1 post-contrast MRIs demonstrate an extra-axial enhancing right frontal mass with a “dural tail” and local mass effect, consistent with an en plaque meningioma. (c, d) Postoperative axial and sagittal T1 post-contrast MRIs demonstrate gross total resection with resolution of the mass effect
Immediately postoperatively, she remained clinically stable and was neurologically intact. Subsequently, on the first night after surgery, the patient developed focal motor seizures of her left arm. Intracranial imaging was obtained and revealed expected changes, without evidence of hematoma or infarct. The seizures persisted despite several 2 mg boluses of lorazepam and increasing doses of levetiracetam. Over the next several hours, she developed focal status epilepticus and soon became lethargic. She was intubated, started on continuous video EEG, and ultimately required burst suppression with propofol and a fosphenytoin load to control seizures. Approximately 48 h later, the sedation was lifted and the patient was noted to slowly awaken. Over the next 24 h, she became fully alert and was noted to be neurologically intact. She was maintained on levetiracetam and phenytoin and has remained seizure-free.
14.2.3 Case 3
Thirty-two-year-old right-handed female presented to medical attention with a 1-week history of progressive headache, nausea/vomiting, and blurry vision. Intracranial imaging was obtained and revealed a colloid cyst with resultant obstructive hydrocephalus (Fig. 14.3a, b).
Case 3 Imaging. (a, b) Preoperative axial and coronal FLAIR MRIs demonstrate an intraventricular mass centered at the foramina of Monro, consistent with a colloid cyst. Note the dilated ventricular system, a sign of obstructive hydrocephalus. (c, d) Postoperative axial and coronal FLAIR MRIs demonstrate gross total resection with resolution of the hydrocephalus
The patient was admitted to the ICU and noted to be awake and alert. Given her preserved mental status, an emergent external ventricular drain (EVD) was not required; however, an EVD kit was placed at bedside while operative preparations were made. The patient was started on high-dose IV dexamethasone and taken to the operating room the following morning for resection of the colloid cyst. Postoperatively, the patient had complete resolution of her symptoms; intracranial imaging revealed gross total resection of the lesion and resolution of the hydrocephalus (Fig. 14.3c, d).
14.3 Initial Evaluation
As with all neurocritical care patients, the initial evaluation of a brain tumor patient should begin with a thorough neurological exam. In particular, providers should focus on the patient’s mental status and assess for the presence or absence of focal neurologic deficits. The initial evaluation should also include a review of the available intracranial imaging, typically a CT and/or MRI. In general, if a brain tumor patient presents in an emergent fashion, a non-contrast CT of the head should be obtained to evaluate for an acute neurologic emergency (i.e., hemorrhage, infarct, herniation). However, in non-emergent cases, the preferred imaging modality is an MRI of the brain with and without contrast, which provides superior delineation of the tumor and brain parenchyma. Most brain tumors have unique imaging characteristics, which help to identify them from one another (Fig. 14.4). Following review of the exam and imaging findings, the patient should be quickly stabilized and treated in accordance with the interventions described below.
MRI images depicting the most common primary and secondary CNS tumors. (a) Coronal T1 post-contrast MRI demonstrating a convexity meningioma. Note the extra-axial location, homogenous enhancement, and presence of a “dural tail” (arrow). (b) Coronal T1 post-contrast MRI demonstrating a pituitary macroadenoma with suprasellar extension and compression of the optic chiasm (arrow). (c) Axial T1 post-contrast MRI demonstrating a glioblastoma. Note the intra-axial location, thick peripheral enhancement, and central necrosis. (d) Axial T1 post-contrast MRI demonstrating multiple brain metastases. Note the numerous intra-axial enhancing lesions near the grey-white junction with associated vasogenic edema
14.4 Interventions and Management
14.4.1 Routine Postoperative Management
The majority of brain tumor patients are admitted to the ICU for routine postoperative care. In most hospitals, patients undergoing a cranial tumor surgery will spend one night in the ICU immediately after surgery. This allows for close monitoring and rapid identification of changes in neurological exam. If a change in neurologic status is identified, brain imaging (typically, a non-contrast CT Head) must be obtained expeditiously to evaluate for frequent postoperative complications, including hemorrhage, infarct, and pneumocephalus. Additionally, the ICU setting allows for prompt treatment of pain, nausea, and vomiting, symptoms which are common in the first 24 h following cranial surgery. The routine care of most postoperative brain tumor patients includes the administration of intravenous fluids, corticosteroids (most commonly, dexamethasone), narcotics, and antiemetics. Additionally, TED hoses and sequential compression devices are utilized to decrease the risk of deep venous thrombosis. Neurological exams are performed every hour. Systolic blood pressure is typically maintained <140 mmHg (using labetalol, hydralazine, and/or nicardipine). Foley catheters are utilized to record strict urine input and output. A non-contrasted CT of the head is typically obtained 24 h after the procedure to evaluate the surgical cavity. If the CT scan demonstrates expected findings and the neurological exam is stable, the patient can be transferred to the general floor.