Hospitalists increasingly comanage neurosurgical conditions as part of a multidisciplinary care team. This chapter will present the management of common neurosurgical conditions, including brain tumors, hydrocephalus, stroke and other vascular diseases, traumatic brain injury, spinal cord injury, and degenerative spine disease.

Both primary and metastatic brain tumors can cause significant morbidity and mortality due to their location within the central nervous system. Recognition of the common symptoms including headache, seizures, and altered mental status is important for general physicians. MRI helps to define the location and extent of the tumor and provides a diagnosis. Surgery is often required to confirm the definite pathology and guide further treatment (Table 63-1).

Benign tumors (meningiomas, pituitary adenomas, acoustic neuromas) often have a favorable outcome with surgical resection or radiation therapy including stereotactic radiation. Skull base tumors are more difficult to handle with surgery alone and might require multimodality treatment. Primary malignant brain tumors (gliomas, medulloblastomas) benefit from radiation and chemotherapy. Brain metastases remain a frequent complication of systemic tumors but are temporarily controlled with surgery or radiation therapy. Unfortunately, the mortality rate from malignant brain tumors remains high.

Clinical Presentation

Brain tumors can cause either focal or generalized neurological symptoms. Generalized symptoms include headache, nausea, and vomiting, which are suggestive of increased intracranial pressure. Headache occurs in about half of the patients. When focal headache occurs, it may indicate the precise location of the tumor. The headache may be more severe on awakening in the morning (the so-called “morning headache”). It can be difficult to differentiate from tension headache, cluster headache, and migraine. Seizures occur at presentation in 15–95% of patients with brain tumors, depending on the type of tumor. The seizures are mostly focal but may become generalized and cause loss of consciousness. Focal neurologic deficits, such as hemiparesis, aphasia, and visual loss, are usually subacute onset and progressive and may reflect the location of the tumor. Some tumors may also present with a stroke syndrome.

Diagnosis

Brain CT typically demonstrates a mass lesion with variable contrast enhancement. MRI is the imaging study of choice in evaluating a brain tumor due to its high sensitivity and resolution. On T1-weighted images, most tumors are low signal intensity and may or may not enhance with contrast medium. Generally speaking, more contrast enhancement is observed with high-grade or malignant tumors. The sensitivity and specificity of these imaging study techniques are not high enough to make the diagnosis, and definitive diagnosis still requires a surgical biopsy or resection to examine the pathology. Because most primary brain tumors remain localized to the brain, systemic staging is not necessary. However, medulloblastoma, ependymoma, and germ cell tumors may spread via the cerebrospinal fluid pathway. Therefore, MRI of the spine should be performed for these patients to rule out cerebrospinal fluid seeding.

Treatment

Surgery

For meningiomas, pituitary adenomas, and vestibular schwannomas surgery is all that is needed. In gliomas, an aggressive resection of the tumor with preservation of the functional area appears to improve prognosis. Biopsy is generally reserved for patients with tumors in the eloquent region of the brain where resection might result in unacceptable neurologic deficit. The goal of surgery in patients with primary CNS lymphoma or germ cell tumors is biopsy only because these tumors are highly responsive to chemotherapy or radiotherapy. Recent advances in surgical technology have facilitated tumor removal with low perioperative morbidity. For example, infiltrative gliomas in the vicinity of functional brain regions can be aggressively removed if the surgery is performed with the patient awake during the operation to map critical regions such as the speech area. Another useful tool is navigation, using preoperative imaging to guide surgery within critical regions and allowing the surgeon to access the tumor safely and accurately. “Brain shift” due to cerebrospinal fluid egress after dural opening may occur and the images are not real-time. Intraoperative MRI provides the surgeon with real-time updated data on tumor volume and location so that he can achieve maximal resection of the brain tumor.

Radiation Therapy

Radiotherapy, an important adjunct treatment for many patients with brain tumors, prolongs survival for most. Whereas whole-brain radiation may be administered for certain tumors, such as primary CNS lymphomas and multiple metastases, conformal radiation using multiple field techniques has become the standard of treatment for most patients with glioma. This type of radiation has been as effective and reduces the dose of radiation to normal brain tissue, therefore reducing radiation-related injury.

An important form of focal radiotherapy used to treat many benign and metastatic brain tumors, stereotactic radiosurgery (SRS) delivers a high radiation dose in a single fraction to an image-defined target while minimizing the radiation to the surrounding critical structures. SRS treatment spares normal structures by using conformal dose plans that deposit large radiation doses into the target with a rapid fall off of radiation at the edges of the dose plan. However, SRS seems to be less effective for infiltrative brain tumors. Fractionated stereotactic radiotherapy (SRT) combines the advantages of SRS with the biological benefit of fractionation. These advantages are helpful when treating lesions that are of greater volume (greater than three centimeters) or near vulnerable structures such as the optic nerves.

Chemotherapy

Chemotherapy provides only modest benefit for most patients with brain tumors, but exerts a crucial synergistic effect in combination with surgery and radiation therapy for patients with high-grade glioma. The most commonly used agent is temozolomide, which is an alkylating agent that penetrates the blood-brain barrier. Temozolamide exerts a modest increase in survival for patients with high-grade glioma. It may cause bone marrow suppression. Carmustine-impregnated degradable polymers (Gliadel wafer) placed within the resection cavity have been safe with a modest increase of survival for newly diagnosed high-grade gliomas and recurrent glioblastoma. Nitrosoureas also have modest antitumor activity in patients with oligodendroglioma. Platinum-based regimens have antitumor efficacy for medulloblastomas and germ cell tumors. High-dose methotrexate regimens are the current primary treatment for patients with primary CNS lymphomas. Currently, multiple agents that target different signaling pathways, such as epidermal growth factor receptor inhibitors and angiogenesis inhibitors, are under investigation and show promise in early clinical trials.

Importance for General Doctors

Corticosteroids, anticonvulsants, and anticoagulants are important medications for the management of patients with brain tumors. Steroids should be started as soon as the diagnosis is made if there is mass effect or edema around the tumor. Corticosteroids are useful for decreasing vasogenic edema, thus controlling increased intracranial pressure. Their long-term use can result in substantial adverse effects. Patients who present with seizures should be treated with anticonvulsants. Anticonvulsants, such as phenytoin and carbamazepine, that induce hepatic cytochrome P-450 enzymes, increase the metabolism of many chemotherapeutic agents. For this reason anticonvulsants that do not induce these enzymes, such as levetiracetam, are generally preferred. It is not necessary to give prophylactic antiepileptic drugs in patients who have never had a seizure

Clinically apparent deep vein thrombosis or pulmonary emboli that require anticoagulation drugs may occur in 20–30% of patients with brain tumors. Conventional therapy with heparin and warfarin is usually effective and well tolerated. Patients receiving anticoagulants that are maintained within the therapeutic range do not appear to have a higher risk of intracranial hemorrhage than those without anticoagulants.

Normal pressure hydrocephalus (NPH) is an important cause of gait disturbance and memory loss in the elderly, perhaps involving as many as 5% of patients thought to have Alzheimer disease. It has been classically defined by dementia, gait disturbance, urinary incontinence, and ventricular enlargement.

NPH is most prevalent in the sixth and seventh decade, although it can be seen at any age. When it occurs secondarily to other conditions such as subarachnoid hemorrhage, traumatic brain injury, and meningitis, this syndrome is referred to as secondary NPH. Otherwise, the term idiopathic normal pressure hydrocephalus (INPH) is used to describe the syndrome. Since the clinical presentation and progression of this disorder has great variation, its diagnosis often represents a challenge for clinicians. There is little consensus regarding the selection of patients for shunt implantation although various supplemental tests, including the CSF tap test, external CSF drainage, and measurement of CSF outflow resistance, have been applied to predict surgical response. In general, CSF shunting provides significant symptom improvement in 60–80% of patients with NPH.

Clinical Presentation

Normal pressure hydrocephalus is classically described as having three characteristic features: gait disturbance, cognitive dysfunction, and urinary incontinence. There must also be ventricular dilation. Dysfunction of periventricular white matter tracts, particularly those related to frontal lobe connections, has been proposed as the mechanism for these clinical features.

Gait disturbance is the most prominent feature in early stage NPH and the most responsive deficit to a CSF shunting procedure. The gait disturbance has been described as magnetic gait, gait apraxia, or a fontal ataxia. The most characteristic appearance is the patient’s feet being “stuck to the floor.” Other characteristic findings include short steps, broad-based and decreased stride length, and height. Postural instability is also frequently seen and the patient may present with frequent falls.

The cognitive dysfunction of NPH includes decreased attention, recent memory difficulty and concentration, psychomotor slowing, and apathy. Features such as aphasia, agnosia, and apraxia are less seen in NPH patients.

Treatment

The treatment of choice for NPH is CSF shunting, usually from ventricle to peritoneum. Significant clinical improvement can be seen in 60–80% of patients.

The shunt system consists of a proximal catheter (ventricular catheter), a valve, and a distal catheter (can be peritoneal, pleural, or atrial). Many types of valves are available, including differential pressure valves and flow-limiting valves. In the former, the CSF shunting occurs only when the pressure difference across the valve is greater than a certain value. Fixed pressure valves are classified as low (2–5 cm H2O), medium (5–10 cm H2O), or high pressure (10–15 cm H2O). With differential pressure valves there is the possibility of CSF overdrainage when the patient changes position from supine to upright. Therefore, the antisiphon device (ASD) was devised to solve the problem of gravity-dependent drainage. Flow-limiting valves provide a constant CSF flow rate over a range of pressure gradients. There is currently no evidence suggesting one shunt system works better or results in better outcomes than the others.

Recently programmable or adjustable valves have been developed. They have different pressure settings and allow adjustment of the pressure setting transcutaneously. Some of these shunt systems are susceptible to external magnetic fields including MRI and even small magnets. Therefore, patients with programmable shunts should have their shunt reprogrammed as soon as possible after MRI.

Importance for General Doctors

NPH’s triad of dementia, gait disturbance, and urinary incontinence, is an important cause of reversible gait disturbance and dementia in the elderly. The shunt procedure is simple with modest intraoperative and perioperative complications. Improvement in gait usually occurs within three months and dementia within six months. If gait worsening or general drowsiness occurs postoperatively, a head CT scan should be performed. A shunt series of plain X-ray films that visualize the entire shunt system is also helpful to exclude disconnection.