Arnold-Kiari's anomaly

Arnold-Kiari's anomaly – inborn defect in development of a rhombencephalon. This anomaly by discrepancy of the sizes of back cranial area and the brain components located in it is shown. As a result it leads to the fact that a part of almonds of a cerebellum and brain falls to a big occipital opening where they are restrained.

Reasons of development of anomaly of Arnold-Kiari

Statistically, this pathology is observed at 3-8 people from each 100 thousand.

Today the exact reason of development of anomaly of Kiari is not established. Most likely, display of this disease is accompanied by three following factors:

• traumatic damage of a wedge-shaped and occipital and wedge-shaped and trellised part of a slope as a result of a birth trauma;
• the inborn osteoneuropathies having a hereditary factor;
• hydrodynamic blow of cerebrospinal fluid in walls of the central channel of a spinal cord.

What anatomic changes happen at Arnold-Kiari's anomaly?

At this pathology the cerebellum is in a back cranial pole.

Normal the lower part of a cerebellum (almond) has to be located above a big occipital opening. At Arnold-Kiari's anomaly of an almond are located in the vertebral channel, that is under a big occipital opening.

The big occipital opening serves as a peculiar border between a backbone and a skull, and also between back and a brain. Over this opening the back cranial pole, and under it – the vertebral channel is located.

The lower part of a brainstem passes (myelencephalon) into a spinal cord at the level of a big occipital opening. Normal liquor (cerebrospinal fluid) has to circulate freely in subarachnoid spaces of a spinal and brain cord. These subarachnoid spaces connect among themselves at the level of a big occipital opening that provides free outflow of cerebrospinal fluid from a brain.

At Arnold-Kiari's anomaly of an almond are located under a big occipital opening that complicates free current of liquor between a head and spinal cord. Almonds of a cerebellum block a big occipital opening like a stopper that significantly breaks outflow of cerebrospinal fluid and leads to development of hydrocephaly.

Types of anomaly of Arnold-Kiari

In 1891 Kiari defined four main types of pathology and in detail described everyone. Doctors use this classification also till today.

• 1 type. Omission of structures of a back cranial pole below the plane of a big occipital opening is characteristic of it.
• 2 type of which caudal dislocation of lower parts of a skull, the 4th ventricle and myelencephalon is characteristic. Quite often it is followed by hydrocephaly.
• 3 type. This type of a disease is quite rare and the rough caudal shift of all structures of a back cranial pole is characteristic of it.
• 4 type when the hypoplasia of a cerebellum occurs without its shift down.

The third and fourth types of anomaly of Arnold-Kiari will not respond to treatment and, as a rule, lead to a lethal outcome.

At preferential most of patients (about 80%) Arnold-Kiari's anomaly is combined with a myelosyringosis – pathology of a spinal cord of which formation of the cysts in it promoting development of the progressing myelipathy is characteristic. Similar cysts at omission of structures of a back cranial pole are formed and as a result of a prelum of cervical department of a spinal cord.

Symptoms of anomaly of Arnold-Kiari

The following clinical signs are characteristic of this pathology:

• loss of temperature and painful sensitivity of upper extremities;
• the pain in cervicooccipital area amplifying during the sneezing and cough;
• visual acuity loss;
• loss of an animal force of upper extremities;
• frequent dizzinesses, faints;
• spasticity of the lower and upper extremities.

At more started disease stages weakening of a gag reflex, episodes of an apnoea (temporary cessation of breathing) and the involuntary bystry movements of eyes join symptoms of anomaly of Arnold-Kiari.

This disease is fraught with development of the following complications:

• The paralysis of nerves of a skull, infringement of cervical department of a spinal cord, dysfunction of a cerebellum happening against the background of the progressing symptoms of intracranial hypertensia.
• Sometimes, that this pathology connects to defects of a skeleton: occipitalization of the Atlas or basilar impressiya (funneled impression of a craniospinal joint and slope).
• Deformations of feet, anomalies of a backbone.

Sometimes Arnold-Kiari's anomaly passes asymptomatically and it is found only when carrying out the general research of the patient.

Diagnosis of anomaly of Arnold-Kiari

The main diagnostic method of this disease is MRT of chest and cervical departments of a spinal cord and MRT of a brain today. MRT of a spinal cord do preferential for the purpose of detection of a myelosyringosis.

Treatment of anomaly of Arnold-Kiari

If the disease has only one symptom – pain in a neck, then treatment of anomaly of Arnold-Kiari generally conservative. Therapy includes various schemes with use of muscle relaxants and nonsteroid antiinflammatory medicines.

If the effect of conservative treatment insufficient or is absent at all for 2-3 months of treatment, and also in the presence at the patient of symptoms of neurologic insufficiency (weakness and numbness of extremities, etc.), then the doctor, as a rule, offers carrying out operation at Arnold-Kiari's anomaly.

Main goal of carrying out operation at Arnold-Kiari's anomaly is minimizing of infringement of nerve terminations and fabrics and normalization of outflow of cerebrospinal fluid for what the size of a back cranial pole is a little increased in volume. As a result of operation at Arnold-Kiari's anomaly the headache completely disappears or decreases, motive functions and sensitivity of extremities are partially recovered.