Moyamoya, a Japanese term that translates to "a puff of smoke," is used to describe a rare disorder of cerebral arteries that can occur in children or adults and causes multiple strokes. Progressive narrowing of the distal portions of the internal carotid arteries and the proximal portions of the anterior and middle cerebral arteries stimulate dilatation of small collateral blood vessels to reestablish blood flow to the affected region of the brain. These collateral vessels are often insufficient, and ischemic stroke results from inadequate perfusion. This collateral system of blood vessels gives a puff-of-smoke appearance on angiographic imaging (Fig. 1).
Moyamoya vasculopathy was first described in Japan in the 1950s; the term moyamoya disease was first used in the 1960s (Yilmaz, Pritz, Bruno, Lopez-Yunez, & Biller, 2001; Gosalakkal, 2002). However, moyamoya vasculopathy is not limited to the Japanese population, and many cases have been reported in other countries, including Canada, the United States, Europe, Australia, and Africa. There are two distinct classifications of this disorder: moyamoya disease and moyamoya syndrome. Moyamoya disease is used for the group of patients with moyamoya vascular changes with no clear underlying cause. Moyamoya syndrome is used to describe moyamoya vasculopathy in patients with underlying illnesses that may contribute to vascular pathology, such as Down syndrome, sickle-cell disease, neurofibromatosis, and homocystinuria (Garg, Bruno, & Biller, 1997; Gosalakkal). Moyamoya vasculopathy appears to be more common in girls. Scott et al. (2004) reported a 1.6:1 female-to-male ratio, similar to what has been reported in the Japanese literature.
Although the pathologic and physiologic characteristics of moyamoya disease in children have been relatively well studied, the social and emotional effects on children and families affected by this disease have not been explored. This article provides an overview of moyamoya vasculopathy, including definitions, etiology, pathophysiology, clinical presentation, and treatment. This article also provides clinicians with insight into the social and emotional concerns of the parents of 21 children, as well as two adolescents, with moyamoya vasculopathy.
Etiology and Pathophysiology
The etiology of moyamoya vasculopathy is unknown. Many triggers have been associated with the development of moyamoya vasculopathy, including cranial radiation therapy, infection, and cardiac surgeries. Moyamoya vasculopathy has been found in children with known genetic defects such as Down syndrome or neurofibromatosis (Scott, 1999). The other common underlying conditions include hematologic disorders, such as sickle-cell anemia, thalessemia, aplastic anemia, or infectious diseases, such as leptospirosis or tuberculous meningitis (Garg et al., 1997; Gosalakkal, 2002). Scott suggested that risk factors associated with constricting blood vessels within the body might also contribute to the development of moyamoya vascular changes. Such risk factors include oral contraceptive use and chronic smoking or cocaine use.
Clinical Presentation
The multiple areas of vascular stenosis may lead to headaches, seizures, dizziness, visual changes, transient ischemic attacks (TIAs), and strokes. Although some patients are asymptomatic, others experience transient events or acute onset of one or more severe neurologic deficits such as hemiparesis, ataxia, sensory impairment, or aphasia. Developmental delay and persistent neurologic deficits may also be present.
The clinical presentation of moyamoya vasculopathy is sometimes precipitated by hyperventilation, which can occur while crying or shouting during a tantrum or during anesthesia (Garg et al., 1997). Hyperventilation leads to a drop in blood carbon dioxide, which causes cerebral vasoconstriction and a decrease in cerebral blood flow. Hyperventilation can be catastrophic for a child with moyamoya vasculopathy who already has limited perfusion through stenosed vessels. Hypoventilation can also be harmful for children who already have compromised cerebral perfusion.
Some children develop renal artery stenosis and hypertension along with moyamoya vasculopathy, and this adds to the complexity of treatment (Peerless, 1997). Families often feel overwhelmed when they are faced with multiple medical issues of children with moyamoya disease or syndrome.
Emergency Treatment
For children who present with stroke due to moyamoya vasculopathy, supportive care such as intubation and intravenous fluids may be required during the first hours and days to maintain airway, breathing, and circulation and to prevent further brain injury. Hyperventilation must be avoided; blood carbon dioxide should be monitored with intubated children to prevent the carbon dioxide level from dropping too low. No established guidelines for what medications to use for these children exist. Aspirin has been used in the acute phase to decrease propagation of thrombosis in stenosed vessels (Yilmaz et al., 2001), but its use remains controversial. Heparin has been used to treat children with acute stroke (Bowen, Burak, & Barron, 2005) but has not been studied in moyamoya disease. There are no randomized controlled trials of the use of aspirin or heparin for children with moyamoya vasculopathy. Calcium channel blockers such as nicardipine may decrease vasoconstriction and help prevent recurrent stroke (Hosain, Hughes, Forem, Wisoff, & Fish, 1994). With cerebral hemorrhage, a small hematoma can be conservatively managed through blood pressure control, and surgical removal may be indicated if the hematoma is large. If ventricular hemorrhage develops, external cerebrospinal-fluid drainage might be used to prevent increased intracranial pressure. Antiepileptic drugs may be used to control seizure activity.
Chronic Medical Treatment and Rehabilitation
No universally accepted guidelines exist for medications to use for long-term management of moya-moya. Aspirin (Yilmaz et al., 2001) and calcium channel blockers (Hosain et al., 1994) have been used to minimize stroke recurrence by preventing the formation of new thromboses in stenotic vessels. Only a few case reports describe the use of warfarin in children with moyamoya; these reports identify multiple prothrombotic risk factors (Ganesan & Kirkham, 1997). Acetazolamide is sometimes used in the functional evaluation of children with moyamoya because it challenges regional blood flow and can highlight areas of abnormal perfusion (Isobe, Kuroda, Kamiyama, Abe, & Mitumori, 1992). We have seen acetazolamide used clinically both for stroke prevention and to treat headaches of children with moyamoya, but this approach is not well described in the literature.
Rehabilitation plays a key role in the long-term treatment of children with stroke from moyamoya. Occupational therapists, physical therapists, and speech therapists can help maximize function.
Surgical Interventions
Surgical intervention aids in stroke prevention by creating collateral vessels on the surface of the brain. A number of procedures achieve indirect or direct revascularization. Indirect revascularization has been shown to improve neurologic outcomes by reducing the number of future ischemic events (Golby, Marks, & Thompson, 1999). Indirect revascularization procedures include encephaloduroarteriosynangiosis (EDAS), encephalomyosynangiosis (EMS), and pial synangiosis (Fig. 2). These procedures promote the development of collateral vessels on the surface of the brain by suturing the temporal artery or temporalis muscle to the dura or pia. Some medical centers have developed their own variations of these procedures (Lamphere, 2003). Some surgeons will drill multiple burr holes in the skull instead of, or in addition to, performing one of these procedures because burr holes also stimulate new vessel growth. These methods are the most commonly used surgical treatments of moyamoya and are less technically difficult than direct revascularization, but they take time to work. Direct revascularization procedures such as superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis may reestablish adequate cerebral blood flow immediately. The choice of surgical procedure may be based on cerebral angiography and cerebral blood flow results, as well as physician preference. Children usually receive intraoperative electroencephalogram monitoring because they are at risk for stroke during the surgery (Hannon, 1996). Scott et al. (2004) reported that pial synangiosis was effective in stabilizing patients with moyamoya vasculopathy. However, revascularization will not reverse deficits (Fung, Thompson, & Ganesan, 2005). Some surgeons may decide not to operate on children with major neurologic deficits. Scarring and postsurgical restrictions on activity vary depending on procedure and should be discussed with families before surgery.
Nursing Issues
Nurses can help obtain a detailed history at the time of presentation. They should ask about headaches or seizures (Gosalakkal, 2002) and previous episodes of decreased limb use, sensory changes, or difficulty speaking. Parents may not be aware that subtle weakness and aphasia can be signs of a TIA (Lamphere, 2003). Nurses should ask about other underlying medical problems that may not be obvious but could contribute to the etiology of moyamoya vasculopathy, such as neurofibromatosis.
Nurses play an important role in preparing patients and families for surgery. Hannon (1996) describes nursing roles before, during, and after pial synangiosis surgery in detail. She emphasized the importance of making sure that medications such as aspirin and nonsteroidal antiinflammatory drugs such as ibuprofen be stopped weeks before surgery so that intraoperative bleeding does not occur. However, this is controversial. Some neurosurgeons will operate on a child still on low-dose aspirin; orders should be confirmed with the surgeon. Hannon also reviews appropriate preoperative labs, gives guidelines on preoperative teaching and patient assessment for signs of intracranial hypertension or acute stroke, describes the use of intravenous fluids to prevent dehydration and possible ischemia, reviews anesthetic guidelines designed to prevent cerebral vasoconstriction, and reviews the equipment typically used in pial synangiosis surgery. Postoperatively, intensive-care-unit nurses must monitor neurologic status, blood pressure, and fluid status to ensure that adequate cerebral perfusion is maintained and that no new infarcts occur.
Care should be taken to avoid hyperventilation during invasive procedures or surgery. Nomura et al. (2001) found that children had perioperative TIAs during periods of hyperventilation and distress, such as removal of subcutaneous drains, dressing changes, or placement of intravenous catheters. Nurses can help in the care and recovery of patients with moyamoya vasculopathy by ensuring that children have adequate pain management and sedation during painful procedures. Using wound closures that are less painful to remove, such as Steri-Stripstrade; and paraffin gauze, rather than adhesive tape can be helpful.
Educating and supporting the child and family is another key role for nursing staff. Parents should be instructed to inform surgeons and anesthesiologists to avoid hyperventilation. Parents and children need to identify everyday events that may precipitate TIAs. For example, one patient had a TIA while singing a long note during choir practice. The precipitation of TIAs by everyday events is particularly stressful for parents, who may be reluctant to discipline their child for fear of causing a TIA if the child cries.
Nurses and physicians should establish guidelines for restricting physical activities. Some sports such as ice hockey and baseball have a high risk of head injury, and it may not occur to parents to keep their children out of these sports. This can be particularly difficult for parents who are highly invested in their children's sports activities. Schools should be informed about the diagnosis and any restrictions on physical activity. Atherosclerosis does not play a role in moyamoya, but the first stages of atherosclerosis can begin during early adulthood. Encouraging families to make healthy diet and lifestyle choices for their child and for themselves can promote longterm cerebrovascular health for the entire family.
The Experience of Moyamoya
Not surprisingly, parents are shocked and frightened when they learn their children have had TIAs or strokes, because they do not realize children can have strokes. Moyamoya and pediatric stroke outcomes are not well studied. Clear prognostic predictors and management parameters are not available. As a result, parents have extreme anxiety because of fear of the unknown and uncertainty of the long-term outcomes of this disease.
To gain further insight into the concerns of these families, we reviewed medical records on 21 children with moyamoya vasculopathy and conducted telephone interviews, consisting of informal openended questions, with parents and with the two adolescents. This study was approved by the Research Ethics Board of the Hospital for Sick Children as part of the Pediatric Stroke Outcome Study.
Patient Population
The sample included 16 girls and 5 boys seen in the pediatric stroke clinic at Toronto's Hospital for Sick Children. They ranged from 10 months to 15 years of age at the time of diagnosis. All children had cerebral angiography to confirm the diagnosis of moyamoya disease or moyamoya syndrome. Underlying conditions in children with moyamoya syndrome included Down syndrome (1), chromosome abnormality (1), progeria (1), and sickle-cell anemia (1). One child had additional cardiac and renal vascular abnormalities. Two children were adolescents (12 years or older). All children were participants in the Canadian Pediatric Ischemic Stroke Registry.
Concerns Expressed by Families About Moyamoya
The most common concerns expressed by parents were anxiety over the progressive nature of the disease, risk for developmental delay, anxiety about the need for surgery and what surgery would entail, and concern over school issues (Table 1). Many of the children had learning or behavioral issues that interfered with school performance, and many missed school because of their illness. Other concerns included anxiety about recurrent TIA or stroke, headaches, fear of seizures, concern about their child's and family's social isolation because of the illness, and concerns about whether the disease "ran in the family." The two adolescents interviewed were concerned about restriction of activities, whether or not future oral contraceptive use or pregnancy would place them at risk for stroke, and how the diagnosis would affect dating and sexuality.
Anxiety and Uncertainty Over the Progressive Nature of Moyamoya
All families expressed anxiety over the progressive nature of the disease, primarily how cerebral blood vessels would change over time and how this would affect the child's clinical course. One father asked
The doctor told me that his blood vessels would get smaller over time, but shouldn't they get bigger as he grows bigger? If it gets worse, what will happen to him? He already had three strokes. Will he have more strokes? (in translation)
The father of a child who also had cardiac and renal vascular abnormalities demanded that they be fixed: "I want to have all her other problems fixed. Otherwise she will have another stroke. She's a time bomb."
Another parent wrote
There were so many unknowns-the disease we were told was unpredictable; E's recovery from the hemorrhage and strokes (which left her paralyzed on her left side) was a wait-and-see situation. We were overwhelmed and exhausted while trying to provide continual care and reassurance for both our daughters, one in the hospital and one at home [horizontal ellipsis].
These types of fears are common for parents of children with severe illnesses. The uncertainty itself is a significant stressor and often leads to anger and depression (Mishel, 1999). Learning about her child's illness and receiving the support of medical staff helped this mother cope. She continued in her letter, "[horizontal ellipsis]with the help of excellent medical staff, E's gradual progress, and hearing of other children and families who had experienced moyamoya, hope began to creep back into our daily lives."
Fear of Recurrent Stroke or Transient Ischemic Attacks (TIAs)
Seven families expressed fear that their child would have recurrent strokes or TIAs. The facts that TIAs and strokes may be precipitated by ordinary, everyday events and that sometimes there is no clear trigger are worrisome for parents. One of the mothers quit her job to stay home with her child because of her child's frequent TIAs and headaches. She was concerned about stroke recurrence. (On a positive note, this child has been coping better with her headaches since she started seeing a social worker regularly.) Similar fears have been reported from the parents of children with chronic recurring conditions akin to moyamoya, such as cancer (Stewart & Mishel, 2000).
Fear of Seizures
Five families expressed concern about more frequent seizures after surgery. One mother whose child had multiple seizures after EDAS surgery asked, "Will the seizures cause injury to the brain?"
Educating the child and family about seizures is an important part of the care of moyamoya patients. As with other seizure patients, families should be told that brief seizures lasting a few minutes are not thought to be harmful, but an ambulance should be called for longer seizures. They should be reassured that most seizure disorders are treatable with medication. Nurses can tell families that many people with seizures can live nearly normal lives but should be supervised during bathing and must be seizure free for a prolonged period before driving; guidelines vary among states and among countries. Some physicians suggest that patients with seizures avoid swimming, but others permit it with very close supervision, including a "swim buddy" next to him who can pull the child out of the water if he has a seizure. Many families find it comforting when nurses share their own clinical experiences about similar patients who are doing well and living fulfilling lives in spite of their seizure disorder. More detailed information on these issues and other frequently asked questions can be found at the Epilepsy Foundation Web site, http://www.epilepsyfoundation.org/answerplace/quickstart/newlydiagnosed/.
Genetic Issues and Family Planning
The father of a sexually active teenage girl with moyamoya who had increased TIAs while on oral contraceptives asked for guidance. He asked, "She should not be on birth control pills, but she's sexually active, so what is she going to do?"
The patient, who wanted children eventually, and her aunt reported that they had been told by a physician that she might have a stroke if she tried to get pregnant and give birth. Her aunt and father wondered what she should do.
Another patient, a first-born child, was diagnosed with moyamoya after the first stroke. This child had two more major strokes afterward, which left him with aphasia and confined to a wheelchair. The mother had made up her mind not to have any more children because she was afraid that a second child might have moyamoya, and she decided to devote all her energy to taking care of her one child. "It's not fair to him," she said. "He needs a lot of attention. I won't be able to devote all my time to him if we have another child" (in translation).
Moyamoya vasculopathy can be familial, but genetic factors are only one part of the etiology. Several affected children have been described who had unaffected identical twins (Scott et al., 2004). Meeting with a genetic counselor may help families better understand the risk of recurrence.
Anxiety About Surgery
One father said, "It's dangerous to have my child's brain opened up. Is the surgery going to work? How much better is he going to be? Would the surgery make him worse or better?"
Another father explained that the neurosurgeon had recommended surgeries, but he was not sure if his daughter would benefit from the surgery because she was delayed in her growth and development because of another chromosome problem. This father was hesitant to consent to the surgeries. "I am coping well with my daughter's condition and disability right now. I wonder, is surgery necessary? How much better will my daughter get after the surgery? Does the surgery work?"
Surgery is stressful for parents and children. Nurses can empower parents by teaching them about the surgery and what to expect pre- and postoperatively (LaMontagne, 2000).
Adolescent Concerns
Two adolescent girls with moyamoya were interviewed. Both expressed concerns about activity restriction, future stroke with oral contraceptive use, and risk of complications from pregnancy. One had concerns about dating and sexuality.
One adolescent in the study reported concerns about having TIA symptoms and fainting in public and asked, "What if I pass out again in public? What if I pass out while I am driving?"
Adolescents are often concerned about how they appear to others and fear embarrassment. Educating them about their illness and suggesting methods of coping with fearful scenarios can ease their anxiety.
Discussion
Although moyamoya is rare, parents' and children's concerns are universal to all families facing serious illness. Children with moyamoya vasculopathy have a range of medical and social issues related to their disease. Although the female preponderance in our cohort was larger than those described in other studies (Scott et al., 2004), our group included patients with a wide range of ages and contributing etiologies. We feel we have provided a representative sample of parent concerns, because parents of pediatric moyamoya patients of different ages with varying comorbid conditions had similar concerns.
Education is a key role of nurses caring for children with moyamoya. They can educate other staff members about the importance of avoiding hyperventilation before, during, and after surgery, and they can teach patients and families more about what the disease is and what resources are available (Fig. 3).
Emotional support of the child and family is another important role for nurses caring for children with moyamoya vasculopathy. Fear, uncertainty, and anxiety were experienced by most of the families we studied. Although parents did not always explicitly describe their emotions with words such as "sadness" and "grief," grief was an underlying theme as parents had to face having a sick child and grieve for their once-healthy child. Meehan (2005) interviewed five mothers of children who had hemiplegia after strokes and found that they struggled with sadness as they faced their child's disabilities. One of the mothers she interviewed described "mourning what could have been" (p. 269). Nurses should provide information regarding social support groups to help families with the grieving process.
Summary
Nurses can aid in the care of children with moyamoya vasculopathy and their families by educating and supporting families. Families worry about the progressive nature of the disease, recurrent strokes and seizures, and future family planning. Nurses can help families address those fears and empower them in the care of their child.
Acknowledgment
The authors would like to thank Ms. Nina Talib for technical assistance.
References