Susac Syndrome is an autoimmune disease that affects the brain, eye (retina) and inner ear.
This section is intended to help patients, families, their friends, and health care professionals to better understand Susac Syndrome. It is designed to answer questions like:
- How does Susac Syndrome present?
- What symptoms and other abnormalities can it produce in the eyes, brain and inner ear?
- What do we know about the cause?
- How is it diagnosed or misdiagnosed?
- How does Susac Syndrome behave over time?
- How is Susac Syndrome treated and optimally followed?
Susac Syndrome is an autoimmune disease that affects the microvasculature (tiniest arteries and capillaries) of the brain, retina and inner ear---resulting in varying degrees of ischemic injury (injury due to decreased blood flow and oxygen) to these tissues. By autoimmune, we mean that a person's own immune system is mistakenly attacking part of that person's own body. For an explanation of the "immune system" and "autoimmune mistake," go to the section entitled "The Immune System, Autoimmune Mistakes, and the Concept of Immunological Self-Correction" at the end of this section.
Download a PDF to read a brief description Susac Syndrome.
The key to understanding Susac Syndrome is to appreciate the concept of "Autoimmune Endotheliopathy."
- "Endotheliopathy" means that the endothelial cells (EC) are sick.
- "Autoimmune" means that the endothelial cells are sick because the person's own immune system is mistakenly waging an attack on those cells, thereby injuring them.
Download a PDF to read more on the "Cause."
Ophthalmologic Findings of Susac Syndrome
Autoimmune Endotheliopathy In The Retinal Vasculature
Patients with Susac Syndrome typically notice "dark spots" in one or both of their visual fields. This "dark spot" obstructs their vision in that particular portion of their visual field, so that they "can't see anything" in that particular spot. The patient might say, "When I look at your face, I can't see part of it." Some patients describe this as a "black spot," a "pink spot," or a "shadow." Sometimes, instead, patients complain of "flashing lights" appearing somewhere in their visual field.
Download a PDF to read more on the "Ophthalmologic Findings of Susac Syndrome."
This MRI reveals 5 obvious "holes in the corpus callosum.
Autoimmune Endotheliopathy in The Brain
The same endothelial cell swelling, loss of tight-junctions, "leakage," and partial/complete occlusion that is going on in the tiny blood vessels of the retina (see "Eye" section) can go on in the microvasculature of the brain and explains the brain disturbances and the typical MRI brain abnormalities of Susac Syndrome.
MRI abnormalities in Susac Syndrome include the following:
- Abnormalities in the Corpus Callosum:
- Linear defects ("Spokes")
These corpus callosal abnormalities are located in the central portion of the corpus callosum, as opposed to the under-surface of the corpus callosum.
Download a PDF to read more on the "Autoimmune Endotheliopathy In The Brain."
Autoimmune Endotheliopathy In The Inner Ear: Audiologic Abnormalities of SS
The third component of the Susac Syndrome clinical triad is inner ear involvement---involvement of the cochlea and the vestibular apparatus. Again, it is an autoimmune endotheliopathy in the microvascular of the inner ear that is the problem. This endotheliopathy leads to narrowing of the channel within the tiny blood vessels that feed the cochlea and vestibular apparatus, and the resultant decreased blood flow and decreased delivery of oxygen and nutrients causes ischemic injury to these tissues.
The figure at right shows the anatomy of the inner ear. Because it is the blood supply to the tip of the cochlea that is most vulnerable, and because the tip of the cochlea is responsible for hearing sounds of low frequency, the autoimmune endotheliopathy of Susac Syndrome primarily causes low frequency sensorineural hearing loss. Loss at other frequencies, however, can also occur. The hearing loss of Susac Syndrome can be on one side, both sides, equal, or unequal. It can develop suddenly, or more progressively. It can be so profound as to require cochlear implants.
Download a PDF to read more on "Autoimmune Endotheliopathy in the Inner Ear."
The clinical course (how the disease behaves over time) and long term outcome of Susac Syndrome differ from patient to patient. Many patients experience an acute or subacute "monophasic encephalopathic course" (figure to right) that lasts 1-2 years and is not followed by any further disease activity.
If the disease during those 1-2 years is relatively mild or is otherwise easily controlled by immunosuppressive medication, the outcome can be very good, i.e. little or no permanent damage sustained. With more severe disease, more prolonged disease, or both, there is potential for permanent, severe irreversible damage, i.e. varying degrees of dementia, visual loss, and deafness.
Download a PDF to read more about the clinical course of Susac Syndrome.
Ideally, treatment of Susac Syndrome should be based on:
- An accurate understanding of the immunopathogenesis (cause) of the disease.
- An accurate understanding of the natural history and potential outcome of the disease.
- The results of controlled clinical trials.
- Individualized consideration of the risks of under-treatment versus the risks of over-treatment.
Unfortunately, our understanding of the immunopathogenesis of Susac Syndrome is quite incomplete. And, to date, our knowledge of the natural history and treatment of Susac Syndrome is based entirely on anecdotal case reports and retrospective analyses of short series of patients. No comprehensive, systematic and prospective study of the clinical features, clinical course, and treatment of Susac Syndrome has been conducted. No controlled studies of treatment have been conducted.
Download a PDF to read more on "Treatment."
Diagnosis & Management
This section is intended to provide guidelines and steps to take regarding the initial diagnosis and long-term management of Susac Syndrome.
Download a PDF on "Diagnosis and Management."
The forms listed below have been developed to facilitate the day-to-day care of individual patients. These forms are designed to be completed by either the physician or the patient/family, or by both. Most of the forms can be completed by the patient/family and need not be completed by the physician. We encourage all patient/families and all physicians of newly diagnosed patients to strongly consider serially using these forms as a way to document and track the patient’s progress.
Many different diseases need to be considered before making a definite diagnosis of Susac Syndrome. Conversely, Susac Syndrome is often misdiagnosed, for example, as "atypical multiple sclerosis (MS)," "unusual demyelinating disease," "atypical ADEM (acute disseminated encephalomyelitis)," or "atypical complex migraine." Therefore, to avoid over-diagnosis and misdiagnosis of Susac Syndrome, it is wise to consider the disease categories listed below:
- Demyelinating Diseases
- Autoimmune/Rheumatologic diseases
- Non-Inflammatory Cerebrovascular disease
- Infectious CNS disease
- Primary CNS lymphoma
- Metastatic CNS malignancy
- Paraneoplastic CNS syndromes
- Migraine syndromes
- Meniere's disease
- Psychiatric disease
- Other Encephalopathy
Download a PDF to read more on "Differential Diagnosis."
Cleveland Clinic has established a Susac Syndrome Program to provide clinical services for patients with Susac’s syndrome. The Susac’s Syndrome Program, which is directed by Robert Rennebohm, MD, has the following components:
The Susac Syndrome Consultation Clinic
The Susac Syndrome Consultation Clinic is designed to comprehensively evaluate patients with definite or suspected Susac syndrome. This clinic is staffed by a collaborative multi-disciplinary team of specialists–the Susac Team–which is comprised of neurologists, ophthalmologists, rheumatologists, ENT specialists, audiologists, neuro-ophthalmologists, neuro-otologists, and neuro-radiologists who have developed special interest in Susac Syndrome.
Patients may be referred from anywhere in the United States, or internationally. Patients come to Cleveland Clinic for at least 3-4 days, during which time they attend a series of scheduled outpatient appointments with appropriate members of the Susac Team. After each member of the Team has completed their evaluation, the Team draws its conclusions and shares its recommendations with the patient and the patient’s home physicians.
The Susac Syndrome MyConsult Program
The MyConsult Program is an online second opinion service available to patients who would like the Susac Syndrome Program to review their medical records (and associated MRIs, fluorescein angiograms, and other studies) and offer an opinion regarding diagnosis and treatment. Steps involved:
- Register securely on the Cleveland Clinic MyConsult website.
- Select Susac Syndrome as your diagnosis, and fill out the appropriate questionnaires.
- Collect and send the required medical records and studies to Cleveland Clinic.
- Once all of this information about your illness has been received, it will be placed in a binder and presented to Dr. Rennebohm, Head of the Susac Team.
- Dr. Rennebohm and other appropriate members of the Susac Team will thoroughly review the information in the binder (including the actual MRI and fluorescein angiography images) and render an opinion regarding diagnosis and treatment.
- Dr. Rennebohm will then be available to work with your home physicians regarding your further care.
An online medical second opinion for Susac Syndrome costs $565. The MyConsult Program is designed for patients who may not want to, or are unable to, come to Cleveland to attend the Susac Syndrome Consultation Clinic.
The Susac Syndrome Website at Cleveland Clinic
A fundamentally important component of the Susac Syndrome Program is the development and maintenance of the website you are currently viewing.
This website was designed to provide comprehensive education about Susac Syndrome – for physicians, patients, families, and anyone else interested in Susac Syndrome. Patients who attend the Susac Syndrome Consultation Clinic or access the MyConsult Program are encouraged to read through this website.
Learn more about this site.
The International Collaborative Study (ICS) of Susac Syndrome
Another key component of the Susac Syndrome Program is the research component. The ICS is designed to learn as much as we can from as many patients as possible. Please see the Clinical Research section of this website.
The Susac Syndrome Program is committed to increasing awareness of Susac Syndrome among physicians throughout the world. Accordingly, Dr. Rennebohm and other members of our Susac Team are available to present information about Susac Syndrome at medical institutions and medical meetings anywhere in the world.
Clinical Study: The Susac Syndrome International Collaborative Study (SuS-ICS)
Most of the currently available information on Susac Syndrome is based on analysis of case reports and relatively small series of patients. There is great need for a comprehensive, systematic, prospective and retrospective, global study of a large number of patients with SS.
The purpose of the Susac Syndrome International Collaborative Study (SuS-ICS), therefore, is to efficiently collect, analyze, and share new, scientifically sound information regarding the clinical features, clinical spectrum, clinical assessment, natural history, treatment, clinical course, and long-term outcome of Susac Syndrome. The study seeks to collect clinical information on at least 50 current, 50 past and 50 future patients with Susac Syndrome, from around the world.
Download a PDF on Susac Syndrome Clinical Study
In 1975 Dr. Susac saw a young woman with a previously unreported combination of problems – a clinical triad of:
- Branch retinal artery occlusions (BRAO)
Shortly thereafter, Dr. John Selhorst referred to Dr. Susac a 40 year old woman with an identical set of clinical findings. In 1979 Drs. Susac, Selhorst, and John Hardiman (the neuropathologist at the Armed Forces Institute of Pathology who interpreted the brain biopsy in the Selhorst case) published a report of these two cases. The title of the report wasMicroangiopathy of the Brain and Retina.
In 1986, Dr. Susac presented a 26 year-old woman with this syndrome to the Dr. William Hoyt at a Neuro-ophthalmological Symposium held in Dr. Hoyt's honor in San Francisco. When Dr. Hoyt, one of the nation's most eminent neuro-ophthalmologists, saw the branch retinal artery occlusions, he announced the diagnosis as "Susac Syndrome."
Because the syndrome is very commonly misdiagnosed as "atypical multiple sclerosis (MS)," Dr. Robert Daroff, then Editor-in-Chief of the medical journal Neurology, asked Dr. Susac to write a brief article on the syndrome for neurologists (1994). Dr. Daroff insisted that the article be entitled "Susac Syndrome." The disease has been called "Susac Syndrome" ever since.
Since the initial report, approximately 300 patients with Susac Syndrome have been reported in the medical literature.
In 2005, at a Susac Syndrome Symposium organized by Dr. Martin Lubow at Ohio State University, Dr. Rennebohm presented to Dr. Susac a case of an adolescent with Susac Syndrome. At that symposium a concept of emphasis was that Susac Syndrome represents an "autoimmune endotheliopathy" and that the immunopathogenesis and treatment of juvenile dermatomyositis might serve as a helpful model in better understanding, treating, and studying Susac Syndrome.
By 2008 it became obvious to Drs. Susac and Rennebohm that an International Collaborative Study of Susac Syndrome would be the most effective and efficient way to increase knowledge about Susac's Syndrome. Accordingly, Drs. Susac and Rennebohm teamed up to create the content on this website to both facilitate the Susac's Syndrome International Collaborative Study and to serve as a major source of education about Susac Syndrome.
The international Neurology community, and Medicine in general, lost one of its greatest clinicians when Dr. Susac died in February, 2012 at the age of nearly 72. He was still generously and compassionately helping patients with Susac syndrome (and their physicians) until a few weeks before his death.
In July, 2012 Dr. Rennebohm moved from Calgary to the Cleveland Clinic to establish and direct a comprehensive Susac Syndrome Program, which includes an International Susac Syndrome Consultation Service and continuation of the International Collaborative Study of Susac Syndrome.
My Personal Story written by Yvonne Heerema
In January 1993 I was a busy family practitioner in Calgary, Alberta and I thought that things were pretty normal except that I was about 8 weeks pregnant and was getting over a cold that had turned into sinusitis. I had one episode of severe dizziness at the end of January. I was more tired than usual and had some trouble focusing on things, but I blamed all my symptoms on early pregnancy. My family, however, had a more significant awareness of what was occurring, and on February 10, 1993 my sister rushed to my house after a bizarre phone conversation, during which I seemed very confused, and brought me directly to my family doctor`s office.
My doctor was alarmed at my slow and abnormal thought processing and sent me straight to the hospital where I was admitted. In hospital I was found to be quite confused and had lost most of my short term memory. I became dizzy and rapidly lost my coordination when walking. Shortly after admission I developed nausea and vomiting and required an intravenous drip to correct dehydration.
There was a series of lab tests, an electroencephalogram, lumbar puncture and a MRI of my head. The tests showed general slowing of my brain waves while the MRI showed widespread abnormal spots throughout the brain. The spinal fluid had an unusually high protein content, no white blood cells and no sign of infection.
My mental functioning decreased significantly during the first week of hospitalization and I was treated with intravenous steroids for three days (pulse methyl prednisone) followed by oral high dose steroids (Prednisone 8o mg daily). An initial diagnosis of atypical multiple sclerosis was made and I was discharged to be followed up in the multiple sclerosis (MS) clinic. I was too ill to worry or think while in the hospital and just slept. In truth I had a severe sickness of the brain which is called encephalopathy and I had lost the ability for normal thought.
Read the rest of Yvonne's story
This contact information is primarily offered for questions regarding the SuS-International Collaborative Study. We suggest that:
- Any questions about the diagnosis and treatment of an individual patient be channelled through the patient’s physician.
- Visitors realize that the material on this website has been designed for information purposes only. It should not be used in place of medical advice, instruction and/or treatment. If you have specific questions, please consult your doctor or appropriate healthcare professional.
Robert Rennebohm, MD
- Director of the of Susac Syndrome Program at Cleveland Clinic
- E-mail: email@example.com
- Phone number: 216.445.6626 or 216.444.2400
Susac Syndrome Program Mailing Address
Susac Syndrome Program
Crile Bldg, Desk A111
c/o Margaret LaPlaca
9500 Euclid Ave.
Cleveland, OH 44195
Online Second Opinion
The MyConsult Program is an online second opinion service available to patients who would like the Susac Syndrome Program to review their medical records (and associated MRIs, fluorescein angiograms, and other studies) and offer an opinion regarding diagnosis and treatment.