Hand Lesions as a Diagnostic Clue in Unexplained SIADH

Area of Science:

• Rheumatology
• Endocrinology
• Dermatology

Background:

• Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is often idiopathic.
• Cutaneous manifestations can be indicative of systemic autoimmune diseases.

Purpose of the Study:

• To investigate the association between chilblain-like hand plaques and autoimmune connective tissue diseases in SIADH patients.
• To determine the diagnostic utility of skin biopsy and serology in identifying underlying conditions.

Main Methods:

• Case study analysis of patients presenting with SIADH and chilblain-like hand plaques.
• Inclusion of skin examination, histopathological biopsy, and serological testing for autoimmune markers.
• Monitoring of serum sodium levels in response to skin condition management.

Main Results:

• Chilblain-like hand plaques were associated with autoimmune connective tissue diseases, specifically discoid lupus erythematosus with Sjögren's syndrome overlap.
• Skin biopsy and serology were crucial in diagnosing the underlying autoimmune conditions.
• Serum sodium levels showed improvement following dermatological treatment, though spontaneous resolution was a possibility.

Conclusions:

• Chilblain-like hand plaques can serve as a significant clinical sign for autoimmune connective tissue diseases in the context of SIADH.
• Integrated dermatological and rheumatological evaluation is essential for comprehensive patient management.
• Caution is advised when attributing serum sodium normalization solely to skin treatment due to potential for spontaneous stabilization.