An interval of clinically silent gastrointestinal bleed in dysautonomic spinal cord injury: a case report.

BACKGROUND: Gastrointestinal bleed (GIB) has high incidence in traumatic spinal cord injured (tSCI) patients and can frequently be life-threatening, especially early post-injury. Several risk factors often compound bleeding risk, some are unique to this patient population. Normally, clinical suspicion for GIB arises from symptoms like coffee-ground emesis, hematemesis, melena or even hematochezia. A hemoglobin drop may be a late sign. Due to tSCI, however, patients often experience neurogenic bowels and dysautonomia, which may delay symptom presentation and complicate timely diagnosis of GIB. We report a case of an almost clinically silent GI bleed in the context of acute cervical tSCI. CASE PRESENTATION: A 21-year-old female presented with cervical cord transection at C-7 in the setting of motor vehicle rollover, for which surgical decompression was performed. During the acute injury phase, she also received a 10-day course of dexamethasone for symptomatic COVID-19 pneumonia. Two weeks after injury, she underwent percutaneous endoscopic gastrostomy (PEG) placement which demonstrated normal gastric and duodenal anatomy. One week later, a large spike (10x) in blood urea nitrogen: creatinine (BUN: Cr) ratio raised concern for GIB, but hemoglobin remained stable, and stool color remained unchanged. The following day, a gastroenterology consult was requested under increased suspicion of GIB from a sudden 3.5 g/dL hemoglobin drop. The patient received blood transfusion and pantoprazole. An upper endoscopy was performed, revealing three small duodenal ulcers. Melanotic stool ensued afterwards. CONCLUSIONS: Due to dysautonomia, clinical presentation of GIB can be significantly delayed in the tSCI patient population, leaving them vulnerable to succumb to illness. This case illustrates the possibility of an interval in which the patient was bleeding, with the sole indicator being an elevated BUN. Our case calls for closer monitoring of and vigilance for tSCI patients, and possibly employment of different strategies to reduce the incidence and enhance early detection of GIB in tSCI patients to subsequently decrease the morbidity and mortality associated with it.

Hydrophobic and Hydrogel-Based Methods for Passive Tissue Clearing.

Optical tissue clearing enables the precise imaging of cellular and subcellular structures in whole organs and tissues without the need for physical tissue sectioning. By combining tissue clearing with confocal or lightsheet microscopy, 3D images can be generated of entire specimens for visualization and large-scale data analysis. Here we demonstrate two different passive tissue clearing techniques that are compatible with immunofluorescent staining and lightsheet microscopy: PACT, an aqueous hydrogel-based clearing method, and iDISCO+, an organic solvent-based clearing method.