Hereditary Sensory and Autonomic Neuropathy Type I (HSAN I)

At a glance

Genetic neurodegenerative disorder characterized by a loss of sensations, especially in the lower extremities, leading to perforating skin ulceration and bone destruction as a result of abnormal functioning of the autonomic nervous system. Type I is the most common form among the five types of HSAN. The disease usually starts during early adolescence or adulthood. The disease is characterized by the loss of pain sensation mainly in the distal parts of the lower limbs such as feet and lower legs.

Synonyms

Acrodystrophic Neuropathy; Burning Feet Syn­drome; Denny-Brown Syndrome I; Hereditary Sensory Neuropathy Type I (HSN I); Hereditary Sensory Radicular Neuropathy; Hick Syndrome; Lumbosacral Syringomyelia; Mutilating Acropathy; Sensory Radicular Neuropathy Type I; Smith-Thévenard Syn­drome; Thévenard Disease II; Thévenard Syndrome; Ulcerative and Mutilating Acropathy.

History

First described by Auguste Nélaton, a French physician and surgeon, in 1852.

Genetic inheritance

Autosomal dominant, chromosome 9q22.

Pathophysiology

Shorter lifespan of ganglion cells in sacral and lumbar dorsal root ganglia.

Diagnosis

Ganglia biopsy showing loss of neuronal cells with amyloid deposits, mainly around the capillaries. At the beginning, Meissner corpuscles count in skin biopsies are normal. With disease progression, loss of these sensory corpuscles occurs. It is sometimes associated with brain atrophy.

Clinical aspects

Onset is between 15 and 40 years of age. Loss of sensitivity in the feet, with painless ulcers, occurs first, followed by shooting pain and lightning pain in the lower legs. Ulcers require years to heal. There is thermal sensory loss of the lower extremities, often extending to the thigh, thermal loss in the hands, and restless legs and burning sensations in the feet. Shortly thereafter, the patient complains of bilateral neurosensory deafness. Normal sweating. The other cranial nerves are not involved. Other features include the presence of normal ocular motility, normal pupils and pupillary reactions, and the absence of nystagmus. Disappearance of ankle and knee jerks is reported. Secondary Charcot-type neurotrophic arthropathy and mutilating acropathy is part of the evaluation. Upper extremities seldom affected. No motor involvement. Deafness is a common feature of the syndrome.

Precautions before anesthesia

Usually patients present with painless cutaneous ulcers for orthopedic procedures. For medicolegal reasons, it is advisable to obtain a neurologic evaluation before and after the procedure. Search for signs of autonomic dysfunction before induction.

Anesthetic considerations

General anesthesia is often preferred, even though regional anesthesia cannot be contraindicated on scientific grounds. However, the undetected preoperative presence of nerve dysfunction may be a source of confusion after the use of regional anesthesia. Proper positioning of the patient on the operating table is essential to prevent pressure point. Similar care ...