Dysautonomia
Dysautonomia refers to a
disorder of autonomic nervous system (ANS) function that generally involves
failure of the sympathetic or parasympathetic components of the ANS, but
dysautonomia involving excessive or overactive ANS actions also can occur.
Dysautonomia can be local, as in reflex sympathetic dystrophy, or generalized,
as in pure autonomic failure. It can be acute and reversible, as in
Guillain-Barre syndrome, or chronic and progressive. Several common conditions
such as diabetes and alcoholism can include dysautonomia. Dysautonomia also can
occur as a primary condition or in association with degenerative neurological
diseases such as Parkinson's disease. Other diseases with generalized, primary
dysautonomia include multiple system atrophy and familial dysautonomia.
Hallmarks of generalized dysautonomia due to sympathetic failure are impotence
(in men) and a fall in blood pressure during standing (orthostatic
hypotension). Excessive sympathetic activity can present as hypertension or a
rapid pulse rate.
Signs and symptoms
The symptoms of dysautonomia are
numerous and vary widely for each individual,symptoms of dysautonomia are due
to inefficient or unbalanced efferent signals sent via both systems.[2] The primary symptoms present in
individuals with dysautonomia include:
·
Dry
mouth
·
Difficulty
swallowing
·
Bowel
incontinence
·
Blurry
vision
·
Sexual
problems
Causes
Dysautonomia may be due to inherited or degenerative neurologic diseases (primary dysautonomia) or it may occur due to injury of the
autonomic nervous system from an acquired disorder (secondary dysautonomia). The
most common causes of dysautonomia include:
- Toxic causes (vincristine)
- Parkinson disease
- Diabetes
- Multiple sclerosis
- Guillain Barre syndrome
- HIV and AIDS
- Eaton-Lambert syndrome
- Postural orthostatic tachycardia
syndrome
- Amyloidosis
- Chronic alcohol misuse
- Lyme
disease
- Spinal cord injury
- Surgery or injury involving the
nerves
In the sympathetic nervous system predominant dysautonomia is common in fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, and interstitial
cystitis, raising the possibility that such dysautonomia could be
their common clustering underlying pathogenesis.
Mechanism
The autonomic nervous system (ANS) is a component of the peripheral nervous system and is made up of two branches: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS).
The SNS controls the more active responses such as increasing heart rate and
blood pressure. The PNS slows down the heart rate and aids in digestion,for
example. Symptoms typically arise from abnormal responses of either the
sympathetic or parasympathetic systems based on situation or environment.
Diagnosis
The diagnosis of dysautonomia should
include measurements of blood
pressure and heart rate while lying flat, and after 3 minutes
of standing.[9] Additional tests and exams to
determine dysautonomia (neuropathy diagnosis) includes the following:
·
Cold
presser
·
Hyperventilation
test
·
Orthostatic intolerance
·
Evaluate
for acute (intermittent) porphyria.
·
Deep
breathing
·
Testing
for abnormalities of BP
·
Thermoregulatory
sweat test
·
Evaluation
of cerebrospinal fluid via lumbar puncture
·
Small fiber neuropathy biopsy
Treatment
There is usually no cure
for dysautonomia. Secondary forms may improve with treatment of the underlying
disease. In many cases treatment of primary dysautonomia is symptomatic and
supportive. Measures to combat orthostatic hypotension include elevation of the
head of the bed, water bolus (rapid infusion of water given intravenously), a
high-salt diet, and drugs such as fludrocortisone and midodrine.
Prognosis
The outlook for
individuals with dysautonomia depends on the particular diagnostic category.
People with chronic, progressive, generalized dysautonomia in the setting of
central nervous system degeneration have a generally poor long-term prognosis.
Death can occur from pneumonia, acute respiratory failure, or sudden
cardiopulmonary arrest.
Reference
link:
মন্তব্যসমূহ
একটি মন্তব্য পোস্ট করুন