Colloid cyst: a case study.
A colloid cyst, or neuroepithelial cyst, is a slow-growing, benign tumor in the anterior third ventricle. The cyst usually blocks the foramen of Monro, causing obstructive hydrocephalus involving only the lateral ventricles. In the era before computed tomography (CT), a 20% rate of sudden death from colloid cysts was reported, possibly related to acute blockage of cerebrospinal fluid (CSF) flow with resultant herniation (Guner, Shaw, & Turner as cited in Greenberg, 2001). Patients most commonly present with signs of intermittent, acute intracranial hypertension, but can present with chronic hydrocephalus. Cysts that cause neurological signs and symptoms are usually greater than 1.5 cm in diameter (Greenberg). Using a case study, this article emphasizes the importance of neurological assessment in identification of potential complications in the patient with a colloid cyst. It also reviews the assessment findings, diagnosis, treatment options, and nursing implications related to the care of patients with colloid cysts.
Patients with colloid cysts most commonly present with signs of intermittent, acute intracranial hypertension, attributed to movement of the cyst on its pedicle, causing episodic obstruction of the foramen of Monro. Chronic obstruction can also occur, producing chronic hydrocephalus. In a study of 38 patients in the era before CT scans, headache was the primary presenting symptom in 68% of the patients (Little & MacCarty as cited in Greenberg, 2001). Less common presenting signs and symptoms include nausea, vomiting, memory loss, personality changes, and gait and visual disturbances (Amy & Walker, 2003). If the cyst only intermittently obstructs the flow of CSF, the patient may be asymptomatic at times. Differential diagnoses to be considered based on these clinical features are other intracranial processes, including any type of central nervous system (CNS) infection, hemorrhagic or ischemic stroke, and other CNS tumors.
ACT scan is the initial radiologic exam conducted in patients presenting with neurological symptoms, and it will generally show hydrocephalus. Magnetic resonance imaging (MRI) is generally the optimal imaging technique because it clearly demonstrates the cyst presence, location, and relationship to nearby structures (Greenberg, 2001). On an MRI, a colloid cyst appears as a somewhat rounded, intraventricular lesion. It is "comprised of a fibrous epithelial-lined wall filled with either mucoid or dense hyloid substance" (Greenberg, p. 437). Ophthalmologic evaluation may be useful if diplopia is a presenting complaint or in the presence of papilledema (Chin & Murphy, 2006). Lumbar puncture is contraindicated in patients with these lesions prior to shunt placement due to the risk of herniation (Greenberg).
Optimal treatment of a colloid cyst of the third ventricle remains somewhat controversial. Historically, shunting without treatment of the cyst was advocated. However, the nature of the obstruction requires bilateral ventricular shunting or unilateral shunting with fenestration of the septum pellucidum to allow flow of CSF through the lateral ventricles. Currently, surgical resection is usually recommended because it can prevent shunt dependency, reduce the possibility of progression of the cyst, and prevent potential sudden neurological deterioration (Greenberg, 2001).
A 65-year-old male presented to a rural emergency department (ED) with a decline in his level of consciousness over the previous 12 hours. According to the patient's wife and his friend, he was fine during dinner on Friday night, but by Saturday morning he was confused and extremely sleepy. He was sent home from the rural ED after a negative workup, including normal blood work. The following day, he presented to the rural ED again after his wife found him confused and disheveled. A CT scan performed at the rural hospital revealed markedly dilated ventricles, thus prompting transfer to our ED for evaluation by a neurologist.
Upon transfer, the patient was more awake, but remained disoriented to place, time, and situation. The patient and his wife denied any medical or surgical history. He took no medications and had no drug allergies. They indicated that he did not smoke or use illicit drugs; however, he drank alcohol occasionally. A slightly unsteady gait was noted upon arrival to our ED, which resolved prior to evaluation by the neurologist. His physical examination was otherwise unremarkable.
Upon examination by the neurologist, the patient had a normal gait with good initiation and a normal base. He had normal strength in his bilateral upper and lower extremities. His ocular movements were intact, including upward and downward gazes, and he had no facial weakness. Other cranial nerves were intact. The patient had no sensory deficits, and no ataxia was found with finger-to-nose and heel-to-shin testing. He was awake, alert, and oriented. Vital signs were as follows: temperature = 99.3 [degrees]F, pulse = 85 beats/min and regular, respiratory rate = 16 breaths/min, and blood pressure = 182/92 mm Hg. Lab results were within normal limits with the exception of slightly elevated neutrophils, ammonia, and B-type natriuretic peptide (BNP).
The neurologist's interpretation of the CT performed at the rural hospital indicated that the patient had hydrocephalus by radiologic criteria. He noted that the ventricles were quite large with the exception of the fourth ventricle, which was of normal size. Because of these findings, the neurologist was suspicious that the patient had obstructive hydrocephalus that may have been intermittently symptomatic from some sort of ball-valve effect. The neurologist recommended an MRI scan to evaluate the aqueduct and locate the site of the obstruction. He also recommended neurosurgical consultation. The patient was admitted that evening to the neuroscience unit for observation and further evaluation.
On arrival to the neuroscience unit, the patient was oriented to self only. His Glasgow Coma Scale score was 14. His speech was clear, his pupils were equal and reactive, and he had 5/5 strength in his upper and lower extremities bilaterally with intact sensation throughout and no pronator drift. He reported no pain or headache. The following morning, he was oriented to person, place, and time. He answered questions more appropriately, and his wife noted that she thought he was returning to his usual disposition. Later that day, the nurse caring for the patient and the nurse practitioner working with the neurosurgery group noted that the patient was quite lethargic, only awakening with repeated verbal stimulation.
The MRI revealed a 1.6 x 1.5 x 1.1 cm colloid cyst at the anterior aspect of the third ventricle, at the foramen of Monro, resulting in marked obstructive hydrocephalus. According to the consulting neurosurgeon, the transependymal absorption of CSF across the ventricles noted on the MRI was consistent with longstanding obstructive hydrocephalus. The neurosurgeon recommended two treatment options: surgical resection of the colloid cyst or ventriculoperitoneal shunting with fenestration of the septum pellucidum via a scope. These options were discussed with the patient and his wife, and the decision was made to proceed with surgical resection of the colloid cyst.
The patient was transferred to the neuroscience intensive care unit (ICU) preoperatively for closer observation because of his intermittently decreased level of consciousness and lethargy. He was started on intravenous (IV) mannitol 25 g every 6 hours and IV dexamethasone (Decadron) 10 mg every 6 hours. The following day, he underwent a left frontal craniotomy for transcortical resection of the colloid cyst, fenestration of the septum pellucidum, and placement of a left frontal ventriculostomy. He was extubated immediately postoperatively and transferred back to the ICU for observation.
In the ICU, the patient was disoriented to place, time, and occasionally situation. Though he reoriented easily, his ability to respond to instructions lasted less than 5 minutes. He was intermittently impulsive in his attempts to get out of bed despite frequent reminders to request assistance. Because these behaviors are common in patients who have undergone craniotomies, nurses had a heightened awareness of the potential for injury. The patient was closely observed and frequently reoriented; other healthcare team members and the patient's family were made aware of his impulsivity and the need to promote safety. His upper and lower extremity strength remained 5/5 bilaterally, and he was able to ambulate steadily with only stand-by assistance. He reported a headache intermittently, which was relieved by hydrocodone/acetaminophen (Vicodin) 5/500 mg. The ventriculostomy was removed due to minimal output on postoperative day (POD) 1, and the patient was transferred out to the neuroscience unit on POD 2.
His care involved physical therapy, occupational therapy, and speech therapy both in the ICU and on the neuroscience unit. He continued to experience some short-term memory loss and confusion, but his memory improved throughout the course of hospitalization. The interdisciplinary team collaborated with the patient and his wife to ensure his safe discharge home. On POD 4, the patient was discharged home with his wife, who agreed to provide 24-hour supervision and care. This was necessary because of his short-term memory loss and confusion.
His discharge medications included a dexamethasone taper, phenytoin (Dilantin) 200 mg twice a day for seizure prophylaxis, and hydrocodone/ acetaminophen as needed for pain. He was instructed to follow up with the neurosurgery group 2 weeks after discharge. Further follow-up with neurosurgery was planned for 6-8 weeks later and then every 2-3 months over the course of the first year. Repeat imaging would be ordered based on surgical and clinical outcomes, but no less than every year postoperatively.
Though relatively rare, colloid cysts are complex in their management and remain potentially life-threatening tumors. Optimal care of a patient with a colloid cyst requires the skill and expertise of an interdisciplinary team including professionals in neurology, neurosurgery, nursing, physical therapy, occupational therapy, speech therapy, and case management. In addition, involving family early in the plan of care is essential in supporting the safety and well-being of the patient. From a nursing perspective, meticulous baseline and ongoing neurological assessments are of paramount importance to promote the best possible outcomes.
Amy, C., & Walker, E. (2003). Not just another headache: Colloid cyst of the third ventricle. Nurse Practitioner, 28(9), 9-12.
Chin, L., & Murphy, K. (2006). Colloid cysts. Retrieved August 23, 2006, from www.emedicine.com/med/topic2906.htm.
Greenberg, M. (2001). Handbook of neurosurgery (5th ed.). New York: Thieme Medical Publishers.
Questions or comments about this article may be directed to Jennifer Richards, MSN RN CNRN, at email@example.com. She is a clinical nurse specialist for neurosciences at Renown Regional Medical Center, Reno, NV.
Narendra Ballard, MSN APN CCRN, is an advanced practice nurse at Sierra Neurosurgery Group, Reno, NV.
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|Author:||Richards, Jennifer; Ballard, Narendra|
|Publication:||Journal of Neuroscience Nursing|
|Article Type:||Case study|
|Date:||Apr 1, 2008|
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