INTRODUCTION: Kayexalate is a powdered suspension of sodium polystyrene sulphonate frequently used for the management of hyperkalemia. The aspiration of this material with associated pneumonitis or bronchitis as been reported in the pediatric and adult population.We report a case where kayexalate particles with giant cell reaction were found at postmortem examination in the lung tissue.
CASE PRESENTATION: A 58-year-old man with history of hypertension, diabetes, Parkinson's dementia, gastro esophageal reflux (GERD) and chronic respiratory failure on mechanical ventilator was admitted for respiratory distress. One year prior to the current admission he developed Klebsiella pneumonia with respiratory failure,subsequently he had three admissions for recurrent pulmonary infiltrates that were treated as nosocomial pneumonias.At this time, the patient was in ARDS.The examination revealed a comatose cachectic male, with normal vital signs and extensive bilateral rhonchi and crackles on lung examination. The CXR and CT scan showed extensive bilateral alveolar infiltrates with air bronchograms and no evidence of pulmonary emboli. Echocardiogram was normal. Laboratory revealed potassium of 5.8 mEq/L and normal WBC count and renal function. Broad spectrum antibiotics and kayexalate (sodium polystyrene sulphonate) were started through gastrostomy. The patient's clinical condition continued to deteriorate and he expired 72 hours after admission. As per review of all prior medical records, this was the first time the patient received kayexalate. Postmortem examination of the lungs revealed acute bronchopneumonia with foci of organizing pneumonia. In addition all lobes showed polygonal plate-like foreign particles.
DISCUSSIONS: Sodium and calcium polystyrene sulphonate are cation exchange resins given orally or by retention enema for the treatment of hyperkalemia. Sodium polystyrene sulphonate (Kayexalate) uniquely stain strongly by a direct Schiff's reagent procedure without any preoxidation and by the Ziehl-Neelsen method.They have the virtually pathognomonic feature of direct Schiff positivity with a characteristic basophilic, amorphous foreign material on histologic sections(1).The identity of this material can be confirmed by Fourier transform infrared microspectrophotometry(2) The possible aspiration of different organic materials might sometime skew the histology.When present,vegetable particles, cotton fibers (such as contaminants from surgical dressings), and amyloid all stain strongly, but they do not have the parallel laminations of kayexalate. The association between the use of this resins and lung disease trace back to 1975 with a case report of aspiration pneumonia due to the administration of calcium resonium in an elderly debilitated patient(1).Pulmonary complications reported with kayexalate aspiration are bronchitis, bronchopneumonia and pneumonitis.Our patient had findings consistent with acute bronchopneumonia with foci of organization and kayexalate particles. Probably his underlying pulmonary condition was bronchiolitis obliterans with organizing pneumonia either primary or infectious related and the kayexalate particles were an incidental finding. The medical literature has suggested that kayexalate is an inert particle but in our case there was evidence of giant cell reaction around the kayexalate particle.
CONCLUSION: Sodium polystyrene sulphonate is commonly given orally for the treatment of hyperkalemia. Pulmonary complications reported with kayexalate aspiration are bronchitis, bronchopneumonia and pneumonitis. We report the incidental postmortem finding of aspirated kayexalate with evidence of giant cell reaction around the kayexalate particle which is unique in its presentation.It is unclear if the aspiration precipitated his demise. This case together with other cases reporting pulmonary complications illustrates the potential complication of oral administration of kayexalate in patients with high risk for aspiration.We suggest that care should be taken to avoid aspiration and a high level of suspicion to monitor for pulmonary complications.
DISCLOSURE: Anant Dalvi, None.