Primary hypertrophic osteoarthropathy

Primary Hypertrophic Osteoarthropathy
Synonyms	Pachydermoperiostosis
Pronounce	N/A
Specialty	N/A
Symptoms	Clubbing of fingers, joint pain, skin thickening
Complications	Arthritis, joint effusion
Onset	Adolescence or early adulthood
Duration	Chronic
Types	N/A
Causes	Genetic mutations
Risks	Family history
Diagnosis	Clinical evaluation, imaging
Differential diagnosis	N/A
Prevention	N/A
Treatment	Symptomatic management
Medication	N/A
Prognosis	Variable
Frequency	N/A
Deaths	N/A

Primary Hypertrophic Osteoarthropathy (PHO), also known as Pachydermoperiostosis, is a rare genetic disorder characterized by the triad of digital clubbing, periostosis of tubular bones, and pachydermia (thickening of the skin). It is a form of hypertrophic osteoarthropathy that occurs without an underlying systemic disease.

Epidemiology

Primary hypertrophic osteoarthropathy is a rare condition, with a higher prevalence in males compared to females. The onset typically occurs during adolescence or early adulthood. The condition is often familial, suggesting a genetic basis.

Etiology

The exact cause of primary hypertrophic osteoarthropathy is not fully understood, but it is believed to be associated with genetic mutations. Mutations in the HPGD gene, which encodes the enzyme 15-hydroxyprostaglandin dehydrogenase, have been implicated in some cases. This enzyme is involved in the degradation of prostaglandins, and its deficiency leads to elevated levels of prostaglandins, contributing to the symptoms of the disease.

Pathophysiology

The pathophysiology of PHO involves increased production and accumulation of prostaglandins, particularly prostaglandin E2 (PGE2), which leads to the characteristic features of the disease. The elevated prostaglandin levels result in increased vascular permeability and stimulation of osteoblasts, causing periostosis and new bone formation. The skin changes, including thickening and furrowing, are due to increased collagen deposition and fibroblast activity.

Clinical Features

The clinical presentation of primary hypertrophic osteoarthropathy includes:

• Digital Clubbing: Enlargement of the distal phalanges of the fingers and toes, leading to a "drumstick" appearance.
• Periostosis: New bone formation along the shafts of long bones, particularly the tibia and fibula, causing pain and tenderness.
• Pachydermia: Thickening of the skin, especially on the face and scalp, leading to a coarse appearance.
• Arthralgia: Joint pain and swelling, often involving the knees, ankles, and wrists.

Diagnosis

The diagnosis of primary hypertrophic osteoarthropathy is primarily clinical, based on the characteristic triad of symptoms. Imaging studies, such as X-ray and bone scintigraphy, can reveal periosteal new bone formation. Genetic testing may identify mutations in the HPGD gene or other related genes.

Differential Diagnosis

PHO must be differentiated from secondary hypertrophic osteoarthropathy, which is associated with underlying conditions such as lung cancer, chronic pulmonary disease, and cyanotic heart disease. Other conditions to consider include acromegaly, thyroid acropachy, and psoriatic arthritis.

Management

There is no cure for primary hypertrophic osteoarthropathy, and treatment is primarily symptomatic. Management strategies include:

• Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): To alleviate pain and inflammation.
• Bisphosphonates: To reduce bone pain and periostosis.
• Surgical Intervention: In severe cases, surgical resection of periosteal bone may be considered.
• Physical Therapy: To maintain joint function and mobility.

Prognosis

The prognosis of primary hypertrophic osteoarthropathy is variable. Some patients experience a stable course with minimal symptoms, while others may have progressive joint and skin changes. The condition does not typically affect life expectancy.

See Also

• Hypertrophic osteoarthropathy
• Digital clubbing
• Periostosis

External Links

• [Link to relevant medical resources]

Rheumatologic diseases

Arthritis is often used to refer to any disorder that affects the joints. Rheumatic diseases usually affect joints, tendons, ligaments, bones, and muscles. Rheumatologic diseases usually affect joints, tendons, ligaments, bones, and muscles.

Connective Tissue Diseases

Rheumatology and	Connective Tissue Diseases
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Arthritis and Rheumatic diseases	Autoimmune diseases
Autoinflammatory diseases	Behçet’s disease
Bursitis	Giant cell arteritis
Gout	Juvenile arthritis
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Osteoarthritis	Polymyalgia rheumatica
Psoriatic arthritis	Reactive arthritis
Rheumatoid arthritis	Scleroderma
Sjögren’s syndrome	Systemic lupus erythematosus (Lupus)
Tendinitis	Rheumatologic diseases