Patient: Mary, a 35-year-old woman with no prior medical history, presented to her primary care physician with fatigue, weight loss, and persistent nausea. These symptoms had been gradually worsening over the past six months, with recent episodes of dizziness and darkening of her skin (hyperpigmentation).
Initial investigation: Laboratory tests revealed low cortisol levels and elevated ACTH levels, suggestive of adrenal insufficiency. However, further tests for secondary causes (e.g., pituitary dysfunction) were negative. The clinical picture remained unclear, raising concerns about autoimmune Addison’s disease.
GIP measurement: Given the emerging evidence for GIP as a potential biomarker, Mary’s physician decided to test her GIP levels. Surprisingly, her GIP levels were found to be significantly lower than the normal range. This finding contrasted with other potential etiologies for her symptoms (e.g., celiac disease), where GIP levels might be elevated.
Confirmation and diagnosis: Based on the low cortisol, elevated ACTH, and abnormally low GIP, along with Mary’s clinical presentation, a diagnosis of primary adrenal insufficiency (Addison’s disease) was confirmed. She was promptly initiated on glucocorticoid replacement therapy, resulting in significant improvement in her symptoms within weeks.
Discussion: This case highlights the potential value of GIP as a biomarker for early diagnosis of Addison’s disease. It demonstrates how GIP levels can provide additional information in situations where other tests are inconclusive. In Mary’s case, the early identification of Addison’s disease through GIP measurement allowed for prompt treatment and prevented potentially life-threatening complications.
- GIP levels may be decreased in Addison’s disease patients, even before classical symptoms appear.
- Measurement of GIP can be a valuable tool for early diagnosis, especially in cases with ambiguous clinical presentations.
- Utilizing GIP alongside other tests can improve diagnostic accuracy and expedite appropriate treatment initiation.