Atypical Pannus: Understanding, Causes, Symptoms, and Treatment

What is atypical pannus?

Atypical pannus refers to an abnormal, inflammatory overgrowth of tissue that deviates from the more commonly understood abdominal pannus, often occurring in specific anatomical locations like joints or the eye, and is typically associated with chronic inflammation or disease processes.

Understanding Pannus

The term "pannus" generally refers to an abnormal layer of tissue. In its most common colloquial usage, particularly within the context of health and fitness, it often describes an apron of excess skin and subcutaneous fat that hangs down over the lower abdomen, frequently seen in individuals who have experienced significant weight loss or severe obesity. However, within medical and kinesiologic contexts, "pannus" has a more specific and often pathological meaning, referring to an inflammatory tissue growth.

Defining Atypical Pannus

When the term "atypical pannus" is used, it specifically highlights forms of pannus that are distinct from the common abdominal skin fold. These atypical forms are characterized by their pathological nature, their location, and their underlying cause, which is typically chronic inflammation or autoimmune disease rather than simply excess adipose tissue. Atypical pannus represents an abnormal proliferation of fibrovascular tissue that can invade and damage surrounding structures.

Common Manifestations and Locations

Atypical pannus can manifest in several key anatomical locations, each with distinct implications:

• Synovial Pannus (Rheumatoid Pannus): This is perhaps the most widely recognized "atypical" form. In autoimmune diseases like rheumatoid arthritis (RA), the synovial membrane (lining of the joints) becomes inflamed and thickens, forming a destructive pannus. This pannus grows over the articular cartilage and subchondral bone, releasing enzymes that degrade these tissues, leading to joint erosion, pain, stiffness, and loss of function.
• Corneal Pannus: In ophthalmology, corneal pannus refers to the growth of a vascularized connective tissue over the cornea. This can be caused by chronic irritation, inflammation (e.g., from severe dry eye, contact lens overwear, or certain infections like trachoma), or autoimmune conditions. Corneal pannus can impair vision by obstructing light and causing corneal scarring.
• Other Less Common Forms: While less frequent, pannus-like growths can also be seen in other inflammatory conditions affecting various organs, where chronic inflammation leads to abnormal tissue proliferation.

Underlying Causes and Risk Factors

The development of atypical pannus is intrinsically linked to chronic inflammation and specific disease processes:

• Autoimmune Diseases: Conditions like rheumatoid arthritis are primary drivers of synovial pannus due to the body's immune system mistakenly attacking its own tissues.
• Chronic Inflammation: Persistent inflammatory responses, whether localized (e.g., in the eye from chronic irritation) or systemic, can stimulate the abnormal growth of fibrovascular tissue.
• Infections: Certain chronic infections, particularly those affecting the eye (e.g., Chlamydia trachomatis causing trachoma), can lead to corneal pannus.
• Genetic Predisposition: Individuals with certain genetic markers may be more susceptible to autoimmune conditions that cause pannus.
• Environmental Factors: For autoimmune conditions, environmental triggers (e.g., smoking) can contribute to disease onset and progression.

Clinical Presentation and Symptoms

The symptoms of atypical pannus vary significantly depending on its location and the structures it affects:

• For Synovial Pannus (e.g., in RA):
  • Joint Pain and Swelling: Often symmetrical and persistent.
  • Stiffness: Particularly severe morning stiffness lasting more than 30 minutes.
  • Reduced Range of Motion: As the pannus erodes cartilage and bone.
  • Joint Deformity: In advanced stages, leading to significant functional impairment.
  • Warmth and Tenderness: Over affected joints.
• For Corneal Pannus:
  • Vision Impairment: Blurred vision, reduced acuity.
  • Eye Redness and Irritation: Chronic inflammation.
  • Photophobia: Sensitivity to light.
  • Foreign Body Sensation: Due to the abnormal tissue growth on the cornea.

Diagnosis

Diagnosing atypical pannus involves a multi-faceted approach, often guided by the specific anatomical location and suspected underlying cause:

• Physical Examination: A clinician will assess the affected area for signs of inflammation, swelling, and functional impairment. For joints, this includes evaluating range of motion and tenderness. For the eye, a slit-lamp examination is crucial.
• Imaging Studies:
  • X-rays: Can show joint space narrowing and bone erosions characteristic of synovial pannus in RA.
  • MRI (Magnetic Resonance Imaging): Provides detailed images of soft tissues, allowing visualization of pannus formation in joints and its extent.
  • Ultrasound: Can detect early synovial inflammation and pannus formation.
• Laboratory Tests:
  • Blood Tests: Inflammatory markers like C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) indicate systemic inflammation. Autoantibody tests (e.g., rheumatoid factor, anti-citrullinated protein antibodies for RA) help confirm autoimmune disease.
• Biopsy: In some cases, a tissue biopsy may be taken from the affected area to confirm the presence and nature of the pannus and rule out other conditions.

Treatment Strategies

Treatment for atypical pannus focuses on addressing the underlying cause, controlling inflammation, and preventing further tissue damage:

• Addressing the Underlying Condition: This is paramount. For rheumatoid arthritis, treatment involves disease-modifying antirheumatic drugs (DMARDs), including conventional synthetic DMARDs (e.g., methotrexate), biologic DMARDs (e.g., TNF inhibitors), and targeted synthetic DMARDs (e.g., JAK inhibitors), to suppress the immune system and reduce inflammation.
• Anti-inflammatory Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids may be used to manage pain and acute inflammation, often as a bridge until disease-modifying therapies take effect.
• Surgical Intervention:
  • Synovectomy: For severe synovial pannus, surgical removal of the inflamed synovial tissue may be performed to reduce pain and preserve joint function, though this is less common with effective medical therapies.
  • Corneal Surgery: For severe corneal pannus affecting vision, procedures like phototherapeutic keratectomy (PTK) or corneal transplantation may be considered.
• Supportive Therapies: Physical therapy and occupational therapy are crucial for maintaining joint function, strength, and mobility in individuals with joint pannus. Eye drops and other ocular treatments may be used for corneal pannus.

Prognosis and Management

The prognosis for atypical pannus largely depends on the underlying cause, the severity of the condition, and the timeliness and effectiveness of treatment. Early diagnosis and aggressive management of the primary disease (e.g., rheumatoid arthritis) are critical to prevent irreversible tissue damage and preserve function.

Long-term management often involves:

• Regular Monitoring: Ongoing assessment by specialists (e.g., rheumatologists, ophthalmologists) to monitor disease activity and treatment effectiveness.
• Adherence to Treatment: Consistent use of prescribed medications is essential for controlling inflammation and preventing pannus progression.
• Lifestyle Modifications: While not directly treating the pannus, maintaining a healthy lifestyle, including regular low-impact exercise (under medical guidance) and a balanced diet, can support overall health and potentially reduce inflammation in systemic conditions.

Understanding atypical pannus is vital for healthcare professionals and knowledgeable individuals, as it represents a significant pathological process requiring specific medical intervention beyond general health and fitness strategies.