Hereditary Sensory and Autonomic Neuropathy Type II (HSAN II)

At a glance

Genetic neurodegenerative disorder characterized by inflammation of the fingers and/or toes with paronychia and whitlows, multiple ulcers (fingers, soles of the feet), and sensory loss in both arms and legs. It affects mostly the transmission of sensory information for pain, temperature, and touch. Type II, congenital sensory neuropathy (also historically known as Morvan’s disease), is characterized by onset of symptoms in early infancy or childhood.

Synonyms

Giaccai (often misspelled Giacci) Familial Neurogenic Acroosteolysis; Giaccai Syndrome; Hereditary Sensory Radicular Neuropathy, Recessive form; Hereditary Sensory Neuropathy Type II (HSN II); Neurogenic Acroosteolysis; Morvan’s disease.

Incidence

Very rare (fewer than 50 cases reported).

Genetic inheritance

Autosomal recessive.

Pathophysiology

Peripheral nerve degeneration of unknown cause. A high urinary excretion of sphingomyelin and lecithin in three sibs of a Turkish family suggested that the pathogenetic mechanism was a disorder of phospholipid metabolism. Several authors believe the disease is nonprogressive.

Diagnosis

Nerve biopsy shows wallerian degeneration of the axons, with reduction of the number of myelinated fibers. Unmyelinated fibers also were involved but to a lesser degree.

Clinical aspects

Age of onset usually is between 5 and 15 years, which is earlier than the dominant type. There is a loss of all modalities of cutaneous sensation in the lower extremities. It is associated with joint and leg swelling that leads to cylinder-shaped limbs. Proximal sensation is preserved and tendon reflexes are lost. There is no deafness or other cranial nerve involvement. No nystagmus or ocular involvement. There is generalized neurogenic osteoporosis, with acroosteolysis and collapse of the distal phalanges, leading to digital clubbing.

Precautions before anesthesia

Patients are often scheduled for amputations secondary to osteomyelitis. Usually no specific cardiovascular or respiratory involvement. No central nervous system problem. No airway problems related to the syndrome.

Anesthetic considerations

Difficult venous access as a result of pachydermoperiostosis and soft tissue swelling. Enhanced body temperature loss caused by hyperhidrosis. Airways usually are not involved by soft tissue swelling, but special attention must be given to this possibility. The position of the patient on the operation table is very important to avoid pressure point. The same precaution must be taken in the postoperative period to prevent pressure sores. Use of regional anesthesia is controversial. In a case report of a 12-year-old child undergoing anesthesia, it was demonstrated that despite reduced pain perception, the requirements for volatile anesthetics were within the expected range for population with normal pain perception. However, the use of opioids postoperatively was not necessary. Intraoperative mild hypothermia was easily managed by adjustment of environmental temperature.

Pharmacological implications