Acro-osteolysis Causes and Features

Acro-osteolysis is an osteolysis of the distal phalanges of the hands and feet. It can affect the terminal tuft [transverse acro-osteolysis] or the shaft of the distal phalanx (band acro-osteolysis).

Acro-osteolysis is often associated with distal digital ischemia, digital calcinosis, or severe sensory neuropathy.

It has been associated with occupational activities, infections, rheumatic disorders (systemic sclerosis, psoriatic arthritis), endocrinopathies, genetic disorders, and lysosomal storage disorders.

A hereditary form also exists.

Clinical Features

Clinical features may vary in different individuals as the spectrum would vary. Fingertips appear bulbous and are associated with shortening of the distal phalanges and pseudo clubbing.

Raynaud phenomenon [discoloration of the fingers and/or the toes after exposure to changes in temperature (cold or hot) or emotional events] may occur.

Sclerodactyly [localized thickening and tightness of the skin of the fingers or toes] and papular fibrotic lesions on the wrists and dorsa of the hands may occur.  Progressive destruction of the bone produces peg-shaped phalanges.

Systemic symptoms would vary with the causative disease but may include fatigue, myalgias, cold hands and feet, paresthesias, reduced libido, and difficulty with hand grip.

Raynaud phenomenon is usually the first symptom to occur in acroosteolysis secondary to PVC exposure..

A rare autosomal dominant variant, sometimes called Band Acroosteolysis, is associated with Hadju-Cheney Syndrome [see below],  caused by a NOTCH2 mutation.

Symptoms of Hadju-Cheney Syndrome can include short stature, generalized osteoporosis, bowing of the long bones, and vertebrae anomalies.

Imaging

Plain radiography is the gold standard for the detection of acro-osteolysis.

. In transverse acroosteolysis, there are linear osteolytic bands in the distal phalanx, while longitudinal acroosteolysis shows “whittling” or penciling of the tufts resulting from their gradual resorption. Both types lead to acronecrosis [resorption of tufts and distal part of fingers].

The terminal tuft is most commonly affected but the shaft of the distal phalanx can also be affected in a few conditions.

Disease Association/Causes

Acroosteolysis can occur in various diseases, list of which is given below.

Multiple digits

Terminal tuft resorption

• Scleroderma
• Raynaud disease
• Psoriatic arthritis
• Frostbite
• Burns
• Trauma
• Hyperparathyroidism
• Epidermolysis bullosa
• Porphyria
• Drugs
  • Phenytoin (occurs in infants of epileptic mothers treated with phenytoin)
  • Ergot poisoning/abuse
• insensitivity to pain, e.g. leprosy
• Juvenile chronic arthritis
• Dermatomyositis
• Vascular occlusion
• Reactive arthritis
• Pityriasis rubra pilaris

Midshaft resorption

• Polyvinyl chloride exposure
• Primary acro-osteolysis or Hajdu-Cheney syndrome
• Hyperparathyroidism (also causes terminal tuft resorption)

Single digit

• Epidermal inclusion cyst
• Glomus tumour of digit

Primary Acro-osteolysis or Hajdu-Cheney Syndrome

Hajdu-Cheney syndrome is a very rare connective tissue disorder mostly diagnosed in adulthood or adolescence with the presence of a positive family history. with only 50 cases reported in the literature . It is also called acro-osteolysis dominant type.

Clinical features include:

• Short stature
• Premature loss of dentition
• Short webbed neck
• Pseudoclubbing
• Shortening of digits
• Painful digits
• Optical atrophy/optic disc oedema
• Hearing loss
• Basilar invagination
• Distinct craniofacial features like frontal bossing, widely spaced eyes, flat nasal bridge, coarse hair etc

It is associated with osteoporosis, bony deformities and acro-osteolysis.

Autosomal dominant inheritance is mainly responsible but can also result from spontaneous mutations.