Susac syndrome

What it is

From: Orphanet

A rare systemic or rheumatologic disease characterized by the triad of central nervous system (CNS) dysfunction, branch retinal artery occlusions (BRAOs) and sensorineural hearing loss (SNHL) due to autoimmune-mediated occlusions of microvessels in the brain, retina, and inner ear.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Headache · Very frequent (99-80%)

Cephalgia, or pain sensed in various parts of the head, not confined to the area of distribution of any nerve.

Abnormal corpus callosum morphology · Frequent (79-30%)

Abnormality of the corpus callosum.

Cognitive impairment · Frequent (79-30%)

Abnormal cognition is characterized by deficits in thinking, reasoning, or remembering.

Confusion · Frequent (79-30%)

Lack of clarity and coherence of thought, perception, understanding, or action.

Generalized hypotonia · Frequent (79-30%)

Generalized muscular hypotonia (abnormally low muscle tone).

Sensorineural hearing impairment · Frequent (79-30%)

A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve.

Visual loss · Frequent (79-30%)

Loss of visual acuity (implying that vision was better at a certain time point in life). Otherwise the term reduced visual acuity should be used (or a subclass of that).

Abnormal emotion/affect behavior · Occasional (29-5%)

A disturbance in the experience or expression of emotion, characterized by alterations in valence, intensity, frequency, or duration. It may also involve emotional responses that are mismatched, exaggerated, or incongruent relative to internal expectations or external contextual stimuli, such as experiencing negative affect in response to neutral or positive events.

Abnormality of eye movement · Occasional (29-5%)

An abnormality in voluntary or involuntary eye movements or their control.

Apathy · Occasional (29-5%)

Apathy is a quantitative reduction of interest, motivation and the initiation and persistence of goal-directed behavior, where often the accompanying emotions, thoughts, and social interactions are also diminished. The individual is typically non-reactive to provocations, positive or negative, and appears to not care. Distinguished from lethargy which involves lack of physical or mental energy.

Atypical behavior · Occasional (29-5%)

Atypical behavior is an abnormality in a person's actions that can be controlled or modulated by the will of the individual. While abnormal behaviors can be difficult to control, they are distinct from other abnormal actions that cannot be affected by the individual's will.

Diplopia · Occasional (29-5%)

Diplopia is a condition in which a single object is perceived as two images, it is also known as double vision.

Dysarthria · Occasional (29-5%)

Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed.

Gait ataxia · Occasional (29-5%)

A type of ataxia characterized by the impairment of the ability to coordinate the movements required for normal walking. Gait ataxia is characteirzed by a wide-based staggering gait with a tendency to fall.

Other findings in the same source

From: Orphanet

Additional reported features include Lethargy (Occasional (29-5%)); Muscle weakness (Occasional (29-5%)); Nausea and vomiting (Occasional (29-5%)); Personality changes (Occasional (29-5%)); Psychosis (Occasional (29-5%)); Somatic sensory dysfunction (Occasional (29-5%)); Tinnitus (Occasional (29-5%)); Upper motor neuron dysfunction (Occasional (29-5%)); Vertigo (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

All ages

Inheritance in the source

From: Orphanet

Unknown

Frequency and the population described

From: Orphanet

Reported case(s): 304.0; Worldwide. This is a published case count, not prevalence. Point prevalence: Unknown; Worldwide; Class only.

Which doctor should you see?

The suggested department for discussing Susac syndrome is Rheumatology, with a rheumatologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Are the findings inflammatory, structural or due to another mechanism?
• Is there evidence that other organs need assessment?
• How will function and any treatment-related risks be monitored?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Susac syndrome. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.