Cerebral atrophy

Cerebral atrophy is a common feature of many of the diseases that affect the brain.^[1] Atrophy of any tissue means a decrement in the size of the cell, which can be due to progressive loss of cytoplasmic proteins. In brain tissue, atrophy describes a loss of neurons and the connections between them. Atrophy can be generalized, which means that all of the brain has shrunk; or it can be focal, affecting only a limited area of the brain and resulting in a decrease of the functions that area of the brain controls. If the cerebral hemispheres (the two lobes of the brain that form the cerebrum) are affected, conscious thought and voluntary processes may be impaired.

Some degree of cerebral shrinkage occurs naturally with age; after the brain completes growth and attains its maximum mass at around age 25, it gradually loses mass with each decade of life, although the rate of loss is comparatively tiny until the age of 60, when approximately .5 to 1% of brain volume is lost per year. By age 75, the brain is an average of 15% smaller than it was at 25. Some areas of the brain such as short-term memory are affected more than others and men lose more brain mass overall than women.

Cerebral atrophy greatly increases in elderly persons (meaning over the age of 75) and especially causes a diminution of functions such as judgement and social appropriateness (which results in the typical characteristic of elderly people engaging in inappropriate or offensive behaviors in front of others). Brain atrophy does not affect all regions with the same intensity as shown by neuroimaging.^[2]

Possible Causes and Associated Diseases and Disorders

The pattern and rate of progression of cerebral atrophy depends on the disease involved.

Injury

Stroke, loss of brain function due to a sudden interruption of blood supply in the brain
Traumatic brain injury
Corticosteroid Use (There appears to be correlations between degree of dosing with corticosteroids and cerebral atrophy)^[3]

Diseases/Disorders

Pick's Disease showing brain atrophy,

Alzheimer's disease (High resolution MRI scans have shown the progression of cerebral atrophy in Alzheimer's disease) ^[4]
Cerebral palsy, in which lesions (damaged areas) may impair motor coordination
Senile dementia, fronto-temporal dementia, and vascular dementia
Pick’s disease, causes progressive destruction of nerve cells in the brain
Huntington's disease, and other genetic disorders that cause build-up of toxic levels of proteins in neurons
Leukodystrophies, such as Krabbe disease, which destroy the myelin sheath that protects axons
Multiple sclerosis, which causes inflammation, myelin damage, and lesions in cerebral tissue
Epilepsy, in which lesions cause abnormal electrochemical discharges that result in seizures
Anorexia nervosa, bulimia nervosa, and other eating disorders
Malnutrition, caused by lack or excess of nutrition from foods
Type II Diabetes, where the body does not use insulin properly resulting in high blood sugar
Mitochondrial encephalomyopathies, such as Kearns-Sayre syndrome, which interfere with the basic functions of neurons

Infections

Where an infectious agent or the inflammatory reaction to it destroys neurons and their axons, these include...

Encephalitis, acute inflammation in the brain
Neurosyphilis, an infection in the brain or spinal chord
AIDS, disease of the immune system

Symptoms

Many diseases that cause cerebral atrophy are associated with dementia, seizures, and a group of language disorders called the aphasias. Dementia is characterized by a progressive impairment of memory and intellectual function that is severe enough to interfere with social and work skills. Memory, orientation, abstraction, ability to learn, visual-spatial perception, and higher executive functions such as planning, organizing and sequencing may also be impaired. Seizures can take different forms, appearing as disorientation, strange repetitive movements, loss of consciousness, or convulsions. Aphasias are a group of disorders characterized by disturbances in speaking and understanding language. Receptive aphasia causes impaired comprehension. Expressive aphasia is reflected in odd choices of words, the use of partial phrases, disjointed clauses, and incomplete sentences.

Reducing the Risk and Treatment

Unfortunately, cerebral atrophy is not usually preventable, however there are steps that can be taken to reduce the risks such as controlling your blood pressure, eating a healthy balanced diet including omega-3's and antioxidants, and staying active mentally, physically, and socially.^[5]

While most cerebral atrophy is said to be irreversible there are some recent studies that show this is not always the case. A child who was treated with ACTH originally showed atrophy, but four months after treatment the brain was seemingly normal again.^[6]

References

Pathology of the nervous system, primarily CNS (G04–G47, 323–349)

Inflammation

Brain	Encephalitis Viral encephalitis Herpesviral encephalitis Limbic encephalitis Encephalitis lethargica Cavernous sinus thrombosis Brain abscess Amoebic

Spinal cord	Myelitis: Poliomyelitis Demyelinating disease Transverse myelitis Tropical spastic paraparesis Epidural abscess

Both/either	Encephalomyelitis Acute disseminated Myalgic Meningoencephalitis

Brain/
encephalopathy

Degenerative

Extrapyramidal and movement disorders	Basal ganglia disease Parkinsonism PD Postencephalitic NMS PKAN Tauopathy PSP Striatonigral degeneration Hemiballismus HD OA Dyskinesia Dystonia Status dystonicus Spasmodic torticollis Meige's Blepharospasm Athetosis Chorea Choreoathetosis Myoclonus Myoclonic epilepsy Akathisia Tremor Essential tremor Intention tremor Restless legs Stiff person

Dementia	Tauopathy Alzheimer's Early-onset Primary progressive aphasia Frontotemporal dementia/Frontotemporal lobar degeneration Pick's Dementia with Lewy bodies Posterior cortical atrophy Vascular dementia

Mitochondrial disease	Leigh disease

Demyelinating

Episodic/
paroxysmal

Seizure/epilepsy	Focal Generalised Status epilepticus Myoclonic epilepsy

Headache	Migraine Familial hemiplegic Cluster Tension

Cerebrovascular	TIA Amaurosis fugax Transient global amnesia Acute aphasia Stroke MCA ACA PCA Foville's Millard–Gubler Lateral medullary Weber's Lacunar stroke

Sleep disorders	Insomnia Hypersomnia Sleep apnea Obstructive Ondine's curse Narcolepsy Cataplexy Kleine–Levin Circadian rhythm sleep disorder Advanced sleep phase disorder Delayed sleep phase disorder Non-24-hour sleep–wake disorder Jet lag

CSF

Other

Spinal cord/
myelopathy

Both/either

Degenerative

SA	Friedreich's ataxia Ataxia telangiectasia

MND	UMN only: Primary lateral sclerosis Pseudobulbar palsy Hereditary spastic paraplegia LMN only: Distal hereditary motor neuronopathies Spinal muscular atrophies SMA SMAX1 SMAX2 DSMA1 Congenital DSMA SMA-PCH SMA-LED SMA-PME Progressive muscular atrophy Progressive bulbar palsy Fazio–Londe Infantile progressive bulbar palsy both: Amyotrophic lateral sclerosis

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