Duane Syndrome: Causes, Symptoms & Treatment

Duane syndrome is a rarely occurring eye muscle paralysis that is congenital. The exact causes of the disease could not be determined until today.

What is Duane syndrome?

Duane syndrome is also known as Stilling-Türk-Duane congenital retraction syndrome, Stilling-Türk-Duane syndrome, or retraction syndrome. This refers to a congenital eye muscle paralysis that occurs very rarely. The condition was named after ophthalmologists Alexander Duane, Jakob Stilling, and Siegmund Türk, who described it between 1887 and 1905. Duane syndrome accounts for about one percent of strabismus cases. Since there are different symptom complexes in Duane syndrome, the disease is divided into different types. In about 80 percent of all affected persons, the syndrome occurs in only one eye. Girls are particularly affected by ocular muscle paralysis, accounting for about 60 percent of all cases. In approximately 70 percent of all sufferers, there are no other health disorders.

Causes

The exact cause of Duane syndrome is still unclear. Some doctors suspect damage to the VI cranial nerve, which is already congenital. In addition, there is misinnervation of the rectus lateralis muscle, for which branches of the oculomotor nerve are responsible. Furthermore, scientists assume hereditary factors. If the rectus medialis muscle of the diseased eye is tensed, the misinnervation with simultaneous activity of the rectus lateralis muscle results in a pulling effect, so to speak. Typical for Duane syndrome is its extensive variation. This is due to the different size ratio between the three parts of the rectus lateralis muscle. These are the section that is normally innervated by the abducens nerve, the area that is defectively innervated by the oculomotor nerve, and the fibrotic region where there is no innervation at all. Furthermore, specifics arise from the circumstance of whether high-threshold or low-threshold neurons are ingrowing.

Symptoms, complaints, and signs

The expression of Duane syndrome varies widely. For this reason, medical science classifies the disease into three types from I to III. Duane syndrome type I is said to occur when there is a slight internal strabismus and slightly decreased adduction when looking straight ahead. Abduction is possible only to the midline. When attempting adduction, there is a slight narrowing of the palpebral fissure, which is accompanied by retraction. About 80 percent of all affected individuals suffer from Duane syndrome type I. Duane syndrome type-II is defined as a significantly more pronounced adduction. Other symptoms include severe narrowing of the palpebral fissure and retraction when adduction is attempted. Abduction exists only to a limited extent and can be performed up to above the midline. During adduction, the eye can be lowered or raised. In Duane syndrome type III, there is significant limitation of adduction and abduction. In addition, retraction may occur without adduction. When the patient attempts to move the eyeball toward the nose, which is called adduction, narrowing of the palpebral fissure occurs. At the same time, retraction of the eyeball into the orbit occurs. Depending on the extent of the disease, movements of the eye towards the temple (abduction) may be limited. The extent of the limitations depends on the stage of the disease. If the patient looks straight ahead, a clear squint (strabismus) is noticeable. This often results in a corresponding forced posture of the head. In some patients, further malformations of the eyes, ears, skeleton, nerves or kidneys are also possible. Sometimes even abnormalities of the heart occur.

Diagnosis

Duane syndrome is diagnosed in an eye clinic or a specialized department of a hospital. Various examination measures are performed with the aim of distinguishing Duane syndrome from other forms of strabismus. These include, first and foremost, electromyography, double-image diagrams, and precise motality analyses. It is also important to exclude abducens palsy (paralysis of the abducens nerve). Duane syndrome is considered difficult to cure. In some cases, strabismus surgery can provide improvement.

Complications

The eye movement disorders that occur with Duane syndrome are divided into types I, II, and III. Mild complications occur in type I, as patients show only a slight inward squint when looking straight ahead. In this case, the eyeball of the affected eye moves significantly toward the nose, with a narrowing of the palpebral fissure and retraction of the eyeball into the orbit. In affected individuals with Type II and Type III syndromes, the ocular motility disorders are much more severe. In type II, the patient can raise or lower the eyes, retraction of the eyeball into the orbit occurs when the eyeball moves beyond the midline, while strabismus is less pronounced. In type III, significant limitations of ocular motility and severe internal strabismus are present. The movement of the eyeball in the direction of the temple and thus all-round vision are only possible to a limited extent. Due to the strabismus, many patients develop a compulsive head posture. Further potential complications are malformations of the ears, eyes, skeleton, nerves and kidneys. In severe disease, usually associated with type III, abnormalities of the heart may also occur. Surgical interventions and visual aids are conceivable, but treatment is difficult. Complete elimination of the complex malformations is not possible in most cases.

When should you see a doctor?

Parents who notice noticeable squinting, narrowing of the palpebral fissure and other signs of Duane syndrome in their child should seek medical attention. If other deformities are noticed on the face or limbs, it all points to a serious condition that needs to be evaluated immediately and treated if necessary. If the child complains of heart palpitations or kidney pain, it is best to contact emergency medical services. Even in the case of non-specific symptoms, clarification by the pediatrician or a specialist is always advisable. In general, unusual symptoms and complaints must be clarified quickly. If there is already a suspicion of a disease, the pediatrician should be consulted immediately with serious complications. The retraction syndrome must be clarified and treated in any case to exclude a severe course. In addition to the pediatrician or family doctor, a specialist for hereditary diseases or an ophthalmologist can also be consulted. A diagnosed syndrome should be treated in a specialist clinic for genetic diseases.

Treatment and therapy

Because Duane syndrome is a rare and complex disorder, treatment turns out to be difficult. Occasionally, performing strabismus surgery may be appropriate. This is to shift binocular single vision to a straight head posture to correct the previous forced posture of the head so that it does not occur in the future. During the procedure, gentle repositioning of the corresponding eye muscles is performed. Either the affected tendon or muscle is shortened, leaving the original muscle attachment. In this way, strengthening of the retraction can be avoided. The success rate of the operation is about 80 percent and leads to an improvement of the optical conditions. Although in principle it can be performed at any age, it only takes place when the affected child is able to walk. In addition, the body’s visual system is not fully developed until the child is three to four years old. Furthermore, easier communication with the patient is possible after a certain age. The type of surgery ultimately depends on which stage of the syndrome the child suffers from. However, according to recommendations of ophthalmologists, surgery should be performed on children only if they suffer from problems with straight-sightedness. In addition to surgical intervention, some aids can also make the child’s life easier. These include prisms on glasses or special seats at school.

Outlook and prognosis

Duane syndrome can only be treated by symptomatic treatment; causative treatment is not possible in this case. Likewise, self-healing does not occur, so affected individuals are dependent on treatment in any case. If no treatment occurs in Duane syndrome, the various malformations of the internal organs remain and usually lead to a reduced life expectancy of the affected person.Treatment depends on the exact malformations and the symptoms. These can be relatively well limited by various surgical interventions. Above all, operations on the eyes are necessary to increase the patient’s quality of life again. However, patients are still dependent on glasses. Malformations of the internal organs are also corrected if a correction is necessary. The further course of the disease depends very much on the exact extent of these malformations. Without treatment, Duane syndrome can lead to severe psychological symptoms, not only for the affected person but also for his or her relatives. Self-help measures can be used to treat many limitations and thus improve the patient’s quality of life.

Prevention

Duane syndrome is categorized as a congenital disorder. For this reason, there is no way to effectively prevent the condition.

Aftercare

With Duane syndrome, there are few options for follow-up care available to the affected person. The patient is primarily dependent on direct treatment by a physician. However, early diagnosis and early treatment in particular have a very positive effect on the further course of this complaint and can prevent further complications or, in the worst case, complete blindness. As a rule, the earlier the disease is detected, the better its further course. In most cases, patients with this disease require surgical intervention. This intervention should be performed at a very early stage in order to guarantee a normal development of the child. Furthermore, after such an operation, the affected person should in any case rest and take care of his body. Efforts or other stressful activities and activities are to be avoided in order not to stress the body unnecessarily. In many cases, patients also need the support of their parents and family to cope with everyday life. In this context, loving and intensive care has a positive effect on the course of the disease. As a rule, Duane syndrome does not reduce the patient’s life expectancy.

What you can do yourself

Duane syndrome requires medical treatment in any case. Accompanying this, different measures can be taken to alleviate the individual symptoms. Accompanying strabismus surgery, regular vision training is recommended. In most cases, the affected child must also wear a visual aid. Aids such as special seats at school can also make the child’s life easier. However, the exact steps to be taken here must be discussed with a doctor. Parents who notice changes in their child’s personality should address this immediately. Often, cosmetic abnormalities lead to teasing and bullying, and the child withdraws from social life. It is advisable to intervene early and talk to teachers if necessary. In the case of pronounced mental suffering, a visit to a therapist is recommended. In principle, parents should inform their child about the disease and explain the symptoms and possible consequences as far as possible. If the visual disturbances persist despite all measures or reappear after a period of freedom from symptoms, the responsible physician must be spoken to again.