What is Hypertrophic Osteoarthropathy?
Hypertrophic osteoarthropathy is a medical condition, which affects the joints and the bones of the body. In hypertrophic osteoarthropathy, the toes and fingers go through a process which is termed as clubbing, where there is enlargement of the extremities resulting in inflammation and pain, especially at the joint level.
Hypertrophic Osteoarthropathy can be primary, i.e. this condition develops on its own or it can be secondary where it is caused by an underlying condition. The primary hypertrophic osteoarthropathy is rare and is inherited. The changes in primary hypertrophic osteoarthropathy develop gradually with no obvious symptoms. The patient visits the doctor initially for mild pain at the shoulder level or in the hand.
Primary hypertrophic osteoarthropathy is also termed as Touraine-Solente-Gole or pachydermoperiostosis named thus after those who described the characteristics of this condition for the first time. In some cases, patients with primary hypertrophic osteoarthropathy can go on to develop those medical conditions, which are thought to cause secondary hypertrophic osteoarthropathy. These medical conditions consist of: patent ductus arteriosus, myelofibrosis and Crohn’s disease. These conditions can develop as late as 6 to 20 years after the initial development of the primary hypertrophic osteoarthropathy.
Types of Hypertrophic Osteoarthropathy
Primary Hypertrophic Osteoarthropathy
Primary hypertrophic osteoarthropathy has three forms which are:
Complete Primary Hypertrophic Osteoarthropathy
- Digital clubbing.
Incomplete Primary Hypertrophic Osteoarthropathy
- No pachydermia.
- Prominent pachydermia.
- Few skeletal manifestations.
Secondary Hypertrophic Osteoarthropathy
Patients suffering from secondary hypertrophic osteoarthropathy commonly complain of pain and inflammation. The fingers of patients with secondary hypertrophic osteoarthropathy are clubbed and there is abrupt onset of symptoms with rapid progression. About 90% of patients suffering from secondary hypertrophic osteoarthropathy also develop a type of cancer. Patients who do not suffer from cancer, however, experience chronic disease commonly at the level of the lungs, heart, lungs, intestines or liver.
Symptoms & Pathophysiology of Hypertrophic Osteoarthropathy
As there is development of clubbing in the fingers and toes, the skin around the nails becomes red and tender. There also can be thickening of the skin with similar changes developing at the level of the tubular bones. Periostosis is a condition where there is abnormal accumulation of bone tissue around the outer surface of the respective bone and this can develop as one of the features of Hypertrophic Osteoarthropathy. Some patients can experience acute burning sensation or pain. The primary changes seen in patients with hypertrophic osteoarthropathy are: Periostosis, digital clubbing and arthritis.
The characteristic feature of digital clubbing is elevation of nail after which there is widening of the distal phalanx. Inflammation at the level of the subungual capillary causes these changes. This inflammation occurs as a result of excessive deposits of collagen, which occurs with interstitial inflammation and edema. There is proliferation of the local capillaries, which further magnifies the inflammatory process. The increased vascular supply to the nail bed along with excessive growth of the connective tissue in the area actually causes the digital clubbing
Periostosis is the formation of new bone along the tubular bones. These changes develop slowly. The distal part of the long bones is more commonly affected and the following bones are more commonly affected: humerus, clavicle, femur, ulna, fibula, radius, tibia, metacarpus and metatarsus. The primary and secondary form of Hypertrophic Osteoarthropathy can be differentiated on the basis of involvement of the bone epiphysis, as the secondary form of Hypertrophic Osteoarthropathy does not have bone epiphysis.
Causes of Hypertrophic Osteoarthropathy
Primary hypertrophic osteoarthropathy is an inherited disease; whereas, secondary hypertrophic osteoarthropathy is commonly found in patients who are already suffering from a type of cancer or a chronic condition, which involves the vital organs. Peripheral non-small cell lung cancer is commonly associated with it. The cancer appears first; however, there are some cases where the symptoms of hypertrophic osteoarthropathy can appear before the symptoms of cancer.
The exact mechanism behind Hypertrophic Osteoarthropathy is not clear. Potential triggers of Hypertrophic Osteoarthropathy include: hormonal imbalance, circulating and neurogenic factors.
Diagnosis of Hypertrophic Osteoarthropathy
Some of the common methods for diagnosing hypertrophic osteoarthropathy are:
- Erythrocyte sedimentation rate (ESR), which is elevated in hypertrophic osteoarthropathy.
- Plasma factors, which are elevated in hypertrophic osteoarthropathy.
- Serum alkaline phosphatase, which is elevated in hypertrophic osteoarthropathy.
- Imaging studies, such as plain x-ray and radionuclide bone scan.
- Angiography can be done for locating increased vascularization at the level of finger pads.
- Other investigations for diagnosis of hypertrophic osteoarthropathy include: bone marrow biopsy and skin biopsy.
- The most sensitive tool for diagnosing hypertrophic osteoarthropathy is Tc-diphosphonate complexes.
Treatment for Hypertrophic Osteoarthropathy
The main aim of treatment for secondary hypertrophic osteoarthropathy is treating the underlying chronic disease or cancer, which is causing the hypertrophic osteoarthropathy. After the malignant growth is removed, improvement is seen in the symptoms which affect the joints and bones within two weeks or one month. However, if there is chronic damage to the affected tissues then the likelihood of reversal of clubbing is very less. One of the commonest tissue changes seen in Hypertrophic Osteoarthropathy occurs as a result of excessive collagen deposits. The symptomatic treatment of Hypertrophic Osteoarthropathy includes painkillers, such as NSAIDs, which provide relief in pain and inflammation.
Other treatment options for hypertrophic osteoarthropathy are:
- Administration of botulinum toxin (Botox), which has temporary effect and improves the patient’s appearance.
- Medications, such as NSAIDs to provide relief from pain and inflammation; Corticosteroids to provide relief from rheumatologic symptoms; retinoids provide relief from symptoms such as pachydermia, folliculitis or seborrhea.
- Colchicine: This is beneficial for patients who have new bone formation which result in pain.
- Other medications include risedronate and tamoxifen citrate.
- In patients suffering from secondary hypertrophic osteoarthropathy, the following treatment is done:
- The primary cause is treated.
- The tumor is resected.
- Chemotherapy and radiation therapy is needed for heart disease.
- Surgical intervention is done for heart conditions.
- Treatment is done if there is any infection.
- Symptomatic treatment is done, which includes Octreotide, Bisphosphonate, NSAIDs, vagotomy, surgery, tumor resection and tumor cytoreduction. Lung transplantation may be done for patients suffering from cystic fibrosis.
- Full liver transplantation or liver grafting can be done for patients suffering from chronic liver diseases.
- In case of cyanotic heart defects, surgery is needed.
- Plastic surgery is required for removing extra facial skin.