#3515 Diabetes insipidus induced by eosinophilic granuloma from pulmonary paragonimiasis: a case report

Abstract Background and Aims Diabetes insipidus (DI) typically causes hypernatremia, but in rare cases like Paragonimiasis, which can lead to eosinophilic granulomatosis and result in syndrome of inappropriate antidiuretic hormone secretion, hyponatremia can occur even in the presence of DI. Method We present a case of a 37-year-old cachectic Filipino female with a history of possible resistant tuberculosis (TB). Despite extensive treatment, her condition did not improve, leading to admission due to severe pulmonary distress. During her hospital course, she experienced chronic polyuria, and her serum sodium levels remained low-normal, with episodes of hyponatremia. Due to inadequate clinical response to treatment, further investigation ultimately confirmed Paragonimiasis as the underlying etiology. Results Upon admission, a complete blood count revealed leukocytosis with a predominance of neutrophils and a significantly elevated eosinophil count. A high-resolution chest CT scan was subsequently performed, revealing multiple small non-calcified and calcified nodules scattered throughout both lungs. Additionally, ground-glass opacities were noted in the right lower lobe and left lung, suggesting pulmonary granulomas and fibrosis secondary to a prior inflammatory process, along with associated bilateral cicatricial atelectasis, bullous changes, air trapping, and a possible lung abscess. To address the underlying pneumonia, infected bullae, and possible lung abscess, the patient was started on a regimen of vancomycin and amikacin for 7 days, followed by ertapenem, which she completed over several months. Endobronchial aspiration was recommended for further evaluation at a specialized facility; however, due to unavailability of intensive care unit beds for potential resistant TB, transfer to another institution was not feasible. Despite aggressive antibiotic therapy, the patient continued to experience a productive cough, hemoptysis, and intermittent dyspnea. Given the CT scan findings, the possibility of pulmonary TB remained a differential diagnosis. The patient presented with significant polyuria, with urine output measured between 4.8 to 5.6 cc/kg/day. This polyuria contributed to her hypotension secondary to dehydration, necessitating continuous fluid resuscitation. Notably, despite episodes of polyuria, serum sodium levels remained low, ranging from 130 to 135 mmol/L. Urine biochemical analysis revealed a urine osmolality of only 171 mOsm/kg H2O and a urine specific gravity of 1.005, leading to a diagnosis of DI. Random serum osmolality was recorded at 287 mOsm/kg H2O. The presence of polyuria and elevated serum osmolality, despite relatively high basal level of vasopressin, suggests a diagnosis of nephrogenic DI. Given the persistence of symptoms and lack of response to treatment, further diagnostic workup was done, including testing for paragonimiasis, a parasitic infection caused by lung flukes. This parasitic infection can manifest with pulmonary symptoms that may be easily misdiagnosed as other respiratory illnesses, such as tuberculosis. Paragonimiasis is a globally prevalent but underrecognized disease, predominantly affecting regions in East Asia, particularly the Philippines, as well as endemic areas in Africa and South America. The diagnostic test confirmed the presence of the infection. Therefore, the patient was promptly treated with praziquantel at a dosage of 600 mg every 8 hours, specifically 2 tablets in the morning and 1 tablet at lunchtime and in the evening for 2 days. Following this treatment, the patient exhibited significant clinical improvement, including a marked reduction in polyuria, and was subsequently discharged. Conclusion This case highlights the importance of considering atypical infectious etiologies, such as Paragonimiasis, in patients with respiratory distress and eosinophilia, especially when standard tuberculosis treatments fail. The resolution of her symptoms following targeted therapy for Paragonimiasis emphasizes the importance of thorough diagnostic evaluations in challenging medical cases.