Binswanger Disease

Binswanger disease also known as subcortical arteriosclerotic degeneration of the white matter encephalopathy is a progressive neurological chronic, uncontrolled, arterial hypertension disorder caused by arteriosclerosis and thromboembolism affecting the blood vessels that supply the white matter and deep structures of the brain (basal ganglia and thalamus). Most patients experience progressive loss of memory and intellectual abilities (dementia), urinary urgency or incontinence, and an abnormally slow, shuffling, the unsteady pattern of walking, usually over a 5-10 year period. The explanation most often proposed is that chronic arterial hypertension is responsible for the narrowing of the small blood vessels due to lipohyalinosis and fibrosis with subsequent blood flow reduction and hypoxia. Due to their vascular etiology, the symptoms and physical findings associated with Binswanger disease may suddenly worsen due to stroke, stabilize and then improve for a brief time, but the patient’s overall condition continues to progress as the blood vessels become increasingly obstructed. Binswanger’s disease represents one of the causes which lead to vascular cognitive impairment alongside cerebral lacunes, amyloid angiopathy, and some forms of Alzheimer’s disease, and it may coexist with any of these disorders.

Symptoms

Affected individuals often become depressed, uncaring (apathetic), inactive, and unable to act or make decisions (abulic). They become withdrawn and exhibit poor judgment, reduced planning and organizational skills, and less spontaneous communication. In addition, affected individuals may have difficulty with speech (dysarthria), swallowing (dysphagia), and urinary bladder control (incontinence). Some patients exhibit abnormalities that are similar to those seen in Parkinson’s disease, such as slowness, poor balance, and short, shuffling steps (Parkinsonism). Tremor is usually not a feature.

Cognitive and behavioral impairment, motor and gait disturbances, falls, and incontinence evolves with periods of stabilization, plateaus, and periods of improvement. A mixture of pyramidal tract signs, extrapyramidal signs, and pseudobulbar signs can often be seen

Many individuals with Binswanger disease have a history of strokes or transient ischemic attacks. Consequently, the symptoms and signs of this disease develop in a stuttering or stepwise fashion; in contrast to the insidious, gradually progressive course of neurodegenerative diseases.

Causes

Binswanger disease is caused by arteriosclerosis, thromboembolism, and other diseases that obstruct blood vessels that supply the deep structures of the brain. Hypertension, smoking, hypercholesterolemia, heart disease, and diabetes mellitus are risk factors for Binswanger disease. Cognitive and behavioral changes are characterized by dementia and a dysexecutive syndrome (changes in attentional control, working memory, and short‐term memory, impulse control, and abulia in the final stages). Rare hereditary diseases such as CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) also cause Binswanger disease. Thus, Binswanger disease is a clinical syndrome of vascular dementia with multiple causes, not a specific disease. The reduced blood flow in brain tissue appears to produce secondary inflammation that may be a target for treatment.

Related Disorders

Symptoms of the following disorders can be similar to those of Binswanger disease. Comparisons may be useful for a differential diagnosis.

Alzheimer Disease
Alzheimer’s disease is a common progressive disorder of the brain affecting memory, intellect, and language function. Alzheimer’s patients are at increased risk of falling, but most exhibit little or no gross locomotor disturbance until very late in the disease.

Dementia with Lewy Bodies (DLB)
Patients with DLB have Parkinsonism and dementia that begin more or less simultaneously. Patients with DLB have difficulty with attention, concentration, and multitasking (executive function). They are also prone to depression, visual hallucinations, sleep disturbances, and day-to-day fluctuations in cognitive function. Memory is often less affected than Alzheimer’s disease. The Parkinsonism in DLB is gradually progressive and consists of slowness (bradykinesia), muscle stiffness (rigidity), stooped posture, and slow shuffling gait that is often poorly responsive to levodopa. Tremor is frequently mild or absent, compared to classic Parkinson’s disease. REM sleep behavior (vocalizations and movement during dreams) is common and may be violent.

Frontotemporal Degeneration
Pick disease and other forms of frontotemporal degeneration typically begin before age 65. The initial presentation is often personality change (e.g., impaired judgment, impulsive behavior, and blunted emotions), which may lead to psychiatric consultation. Loss of communication skills is another common presentation. Motor disturbances may occur early or late in the disease. Gradually progressive dementia occurs in all patients. (For more information on this disorder, choose “frontotemporal” as your search term in the Rare Disease Database.)

Normal Pressure Hydrocephalus
Binswanger disease may be difficult to distinguish from so-called normal pressure hydrocephalus (NPH). Both conditions produce the clinical triad of gait disturbance, dementia, and urinary incontinence. However, NPH progresses gradually, not in the stuttering or stepwise fashion of vascular disease. The ventricular system of the brain commonly enlarges in Binswanger disease and neurodegenerative dementias (hydrocephalus ex vacuo), so distinguishing these conditions from NPH is often difficult.

Many other neurological disorders can cause dementia and memory disturbances.

Diagnosis

The diagnosis of Binswanger disease is usually based on a thorough clinical evaluation, including detailed patient history, physical examination, and magnetic resonance imaging (MRI) or computerized tomography (CT) scanning of the brain. MRI and CT reveal nerve fiber (white matter) degeneration and multiple small strokes in the deep structures of the brain.

The neurological examination showed the following:

Pyramidal tract signs are characterized by hemiparesis regarding the right limbs with a score of 4/5 (on the MRC—Modified Research Council scale). Extensor plantar reflex was objectified in the right leg. The patient also had central face palsy on the same side.
Extrapyramidal signs are characterized by slowness, left upper limb rigidity, hypomimia, and a low‐volume, monotonous speech.
Mild cognitive impairment on MMSE testing (a score of 27/30) and on MOCA testing (25/30). The abilities affected in our patient were visuospatial/executive functions, short‐term memory, and mathematical functions.

Treatment

The ischemic brain damage in Binswanger disease is not reversible, so treatment is focused on reducing risk factors for stroke, thereby retarding the progression of the disease. Treatment usually involves the use of anti-hypertensive drugs to control blood pressure, antiplatelet drugs (e.g., aspirin) or warfarin to reduce thromboembolism, statins to reduce atherosclerosis, smoking cessation, and diabetes control. Antidepressant drugs are helpful in the management of depression associated with Binswanger disease. Another treatment is symptomatic and supportive.