Introduction

Evaluation of hypothesis

Prolactin-inducible protein (PIP)

Current challenges and consequences of the hypothesis

Conclusion

References

Abstract

Primary acquired nasolacrimal duct obstruction (PANDO) is a syndrome of unknown etiology, predominantly affecting post-menopausal females, characterized by progressive inflammation, fibrosis and subsequent obstruction of the nasolacrimal duct. Numerous factors have been proposed as possible etiologic factors and include anatomical configuration, ocular and nasal infections, peri-lacrimal vascular disorders, hormonal influence, lacrimal drainage lymphoid tissue, gastroesophageal reflux disease, topical medications, swimming pool exposure, smoking, genetic factors, autonomic and lysosomal dysregulation. The authors hypothesize Prolactin (PRL) and Prolactin-inducible protein (PIP) play a role in the etiopathogenesis of primary acquired nasolacrimal duct obstruction.

Introduction

Primary acquired nasolacrimal duct obstruction (PANDO) is a syndrome of unknown etiology, predominantly affecting post-menopausal females, characterized by progressive inflammation, fibrosis and subsequent obstruction of the nasolacrimal duct [1–۳]. The resultant clinical manifestations include epiphora and discharge, occasional development of lacrimal sac mucocele or acute dacryocystitis [2]. Numerous factors have been proposed as possible etiologic factors and include anatomical configuration, ocular and nasal infections, peri-lacrimal vascular disorders, hormonal influence, lacrimal drainage lymphoid tissue, gastroesophageal reflux disease, topical medications, swimming pool exposure, smoking, genetic factors, autonomic and lysosomal dysregulation [1–۷]. Prolactin receptors have been identified in the epithelia and submucosal glands of the lacrimal sac and nasolacrimal ducts [6]. They have been proposed as possible extra-pituitary sites of prolactin synthesis. Significant proportions of Prolactin-inducible protein (PIP) has been detected in lacrimal sac extracts [7].