In dysautonomia, the different parts of the nervous system are out of balance. They do not work together as needed.
The nervous system can be divided into two parts:
Central nervous system (CNS). The CNS consists of the brain and spinal cord.
Peripheral nervous system (PNS). The PNS consists of the nerves that travel from the CNS out through the body and back. The PNS itself can also be divided into two parts:
Somatic nervous system. Controls voluntary movement.
Autonomic nervous system. Regulates functions of the body without conscious thought.
Role of the Autonomic Nervous System
The autonomic nervous system works to regulate involuntary, or unconscious, bodily functions. For instance, it can regulate breathing, even if we are not thinking about breathing. It can also regulate:
The autonomic system is part of the PNS. However, some areas of the CNS can also affect the autonomic system. These areas of the CNS include:
The hypothalamus, which regulates hormones
Parts of the brain that respond to emotions
Abnormalities in the Autonomic System
Most of the time, the CNS works with the PNS to keep a balance, or homeostasis, among the systems. This keeps the nervous systems working well. In dysautonomia, these systems do not work properly.
Postural Orthostatic Tachycardia Syndrome (POTS)
POTS is a relatively common type of dysautonomia. It is discussed in detail here.
SIGNS AND SYMPTOMS
Symptoms of dysautonomia can include, but are not limited to:
Orthostatic hypotension (a drop in blood pressure with standing)
Tachycardia (rapid heart rate)
Lightheadedness or dizziness
Nausea or vomiting
Syncope (fainting or passing out)
Intolerance of heat or cold
Frequent urination or urinary accidents
Symptoms of Familial Dysautonomia (FD)
FD is an inherited condition. It usually affects infants shortly after birth. It is also known as Riley-Day syndrome or HSAN Type III. Symptoms include:
Low tone (floppiness)
Low body temperature
Fewer tears produced with crying
Excessive sweating and drooling
Decreased responses to pain
An unusually smooth tongue (absent tastebuds)
In early childhood, children with FD may develop something called autonomic crises. These crises can be very dangerous. They usually consist of:
A sudden onset of vomiting
High blood pressure
DIAGNOSIS AND LABORATORY INVESTIGATIONS
The tests used for this disorder depend on what the doctor thinks is causing it. The tests may include:
Genetic testing may be done if familial dysautonomia or small-fiber neuropathy is suspected. Genetic testing may be done during or even before pregnancy. This is especially common for people with Ashkenazi Jewish heritage since FD is more common in this population.
This looks at blood pressure and heart rate in different body positions. It is used to diagnose dysautonomia in adults. However, it is less likely to detect a problem in children.
This is the best way to detect small-fiber neuropathy in children.
A blood test can show if antibodies are causing an autoimmune version of the disorder.
Information taken from https://www.childneurologyfoundation.org/disorder/dysautonomia/