The nervous system is divided into the central nervous system and the peripheral nervous system. They are part of the central nervous system, which is located in the cranial box and in the vertebral canal: brain, cerebellum, brainstem and spinal cord. The peripheral nervous system, on the other hand, consists of the cranial nerves (which innervate the head and neck), the spinal nerves (which innervate the remaining parts of the body) and the ganglia (particular groups of neurons that receive information from the receptors).
The peripheral nervous system is further subdivided into voluntary, responsible for the control of voluntary movements and the collection of information by the sense organs, and involuntary or autonomous (or vegetative or visceral or autonomous), which controls involuntary body functions. Finally, the autonomic nervous system is divided into two parts with opposite action: sympathetic (originating in the spinal cord) and parasympathetic (originating in the brainstem and spinal cord).
The autonomic nervous system may present a malfunction; one speaks in these cases of neurovegetative dysautonomia or autonomic dysfunction. What is it about or how does it manifest itself? We talk about this topic with Dr. Vincenzo Tullo, Neurologist and Head of the Outpatient Headache Clinic at Humanitas LAB.
Functions of the autonomic nervous system
“The autonomic nervous system regulates the activity of the glands and internal organs such as the heart, stomach and intestines, controlling functions such as dilatation of the pupils, production of saliva and mucus, heart rate, blood pressure, contraction of the bronchi muscles, movements of the stomach and intestines, production of urine, relaxation of the bladder wall and opening of its sphincter.
The sympathetic nervous system is activated especially when the body experiences emergency situations or stress such as attack and escape responses, while the parasympathetic is prevalent in conditions of stability and rest and promotes processes such as digestion and absorption, growth and energy storage,” explains Dr. Tullo.
In what cases do we speak of neurovegetative dysautonomia?
In the presence of a malfunction of the autonomic nervous system we have a neurovegetative dysautonomia (or autonomic dysfunction).
The disorders that can occur are different, such as:
- Alteration of the regulation of blood pressure and heart rate with orthostatic hypotension and hypertension in clinostatissm (lying position);
- Disturbance of respiratory function;
- Disorders of the gastrointestinal system with reduction of gastrointestinal motility, dysphagia, constipation, diarrhea;
- Sexual and urinary disorders with nocturia, pollakiuria, imperiose urination, impotence, loss of sphincter control;
- Thermoregulation disorders;
- Sleep disorders.
Orthostatic hypotension is the most disabling disorder; it is characterized by a reduction of at least 20 mmHg in systolic blood pressure or 10 mmHg in diastolic blood pressure within three minutes of taking up a standing position and manifests itself with light-headedness, tiredness, fatigue, blurred vision, and syncope.
Classification of diseases of the autonomic nervous system
“This classification is very complex. In general, a distinction is made between focal and generalized dysautonomies. The focal points are characterized by a sectorial symptomatology; an example of this is Bernard Horner’s syndrome with ptosis (lowering of the eyelid), miosis (narrowing of the pupil) and facial anhydrosis (absence of sweating on the face) and Adie’s syndrome with the pupil that does not react to light and the abolition of osteotendinous reflexes).
Generalized dysautonomia, on the other hand, is divided into central (brain or marrow level) and peripheral (nerve level) dysautonomies.
The central ones include:
- Pure autonomic insufficiency;
- Autonomic impairment during multisystemic atrophy, which combines autonomic nervous system impairment with central nervous system neurodegeneration;
- Autonomic impairment associated with Parkinson’s disease.
Peripheral dysautonomia is finally divided into acute (Guillain Barré’s syndrome, botulism, porphyria, toxicity) and chronic (hereditary neuropathies, diabetic neuropathies, toxic karyotypes, infectious and paraneoplastic).
The neurology and neurovegetative diagnostics clinic of Humanitas can allow the integrated study of the central and peripheral pathophysiological mechanisms of Vegetative Nervous System diseases”, concluded Dr. Tullo.