Chronic Intestinal Pseudo-obstruction: A Rare Paraneoplastic Syndrome

Abstract

Chronic Intestinal Pseudo-obstruction (CIPO) is a rare digestive disorder that is a disruption in gut motility mimicking obstruction but not associated with a mechanical obstruction. CIPO can be secondary to an underlying pathology or idiopathic. Secondary causes of CIPO are numerous including paraneoplastic process. This case highlights the challenging evaluation of CIPO presenting as a paraneoplastic neurologic syndrome (PNS). A 57-year-old black male with a history of tobacco use presented with symptoms and imaging consistent with a partial small bowel obstruction (pSBO). He underwent an exploratory laparotomy that was unrevealing for the cause of his pSBO and therefore was transferred to a tertiary care center for further evaluation. His initial work-up including ileocolonoscopy was concerning for Crohn's Disease. Due to lack of clinical response with steroids, he underwent an ileocecal resection with pathology negative for Crohn's Disease. His imaging continued to show dilated loops of small bowel with air fluid levels, and he was subsequently diagnosed with CIPO (Figure 1). CT scans of the chest, abdomen, and pelvis showed no signs of malignancy. Work-up for secondary causes of CIPO with a Mayo Clinic Paraneoplastic Autoantibody Evaluation of serum was positive for anti-ganglionic neuronal acetylcholine receptors (ganglionic AchR) and acetyl receptor striational (StrAbs). Two years later, respiratory complaints prompted a repeat CT chest that revealed a pleural effusion, and the pathology was consistent with lung adenocarcinoma (Figure 2). PNS is a rare paraneoplastic process that causes gut dysmotily, most commonly CIPO. Certain onconeural antibodies are specific for gut dysmotility such as type 1 anti-neuronal nuclear antibody (ANNA-1), which has the strongest correlation between gut dysmotility and malignancy. Surprisingly, our patient was negative for ANNA-1. Ganglionic AchR and StrAbs are associated with gut dysmotility and lung cancer, which correlates with the patient's findings. His initial imaging did not show signs of malignancy, which can be expected as symptoms of gut dysmotility due to PNS may occur months prior to diagnosis of the malignancy. No definitive features differentiate paraneoplastic and non-paraneoplastic CIPO, therefore it is important to investigate and continue surveillance for malignancies especially in those who smoke.Figure 1Figure 2