A Case Report and Literature Review of an Uncommon Manifestation of Giardiasis: Protein-Losing Enteropathy in an Immunocompetent Host

Hypoproteinemia can result from multiple etiologies, including malnutrition, hepatic and renal dysfunction, and less commonly, protein-losing enteropathy (PLE). PLE leads to protein loss into the gastrointestinal tract, resulting in decreased oncotic pressure and third-space fluid accumulation. While enteric infections have been implicated in PLE, <i>Giardia lamblia</i> is a rare causative agent, particularly in immunocompetent adults. We discuss the case of a 41-year-old immunocompetent male who presented with progressive generalized edema, weight gain, and skin hypopigmentation over the past six months. Laboratory investigations revealed significant hypoalbuminemia (1.6 g/dL). An extensive evaluation ruled out hepatic, renal, and gastrointestinal pathologies, but the stool analysis confirmed <i>Giardia lamblia</i> cysts, with a positive <i>Giardia</i> antigen test. The patient was treated with a single dose of tinidazole (2 g) and intravenous albumin. Follow-up after two months showed resolution of edema, weight loss, and improved serum albumin levels (2.7 g/dL) and negative stool cultures. While giardiasis typically causes diarrheal illness, this case highlights its rare but significant role in PLE, even in immunocompetent adults. Clinicians should consider stool testing for <i>Giardia</i> in unexplained hypoalbuminemia, as prompt treatment can reverse protein loss and prevent complications. The pathophysiology involves mucosal damage and increased intestinal permeability, leading to excessive protein loss. The few cases of giardiasis-associated PLE highlight the need for heightened clinical suspicion as early recognition and prompt treatment with tinidazole can lead to favorable outcomes, preventing complications associated with prolonged infection.