0 months 3 months 6 months 12 months

ALT (U/L) 156 45 37 38AST (U/L) 146 38 34 35T. bilirubin (mg/dl) 0.8 0.7 0.5 0.5ALKP (U/L) 92 100 86 79Albumin (mg/dl) 1.6 1.6 1.8 2.024 hr protein (gm/24 hrs) 7.8 6.3 2.8 1.7HBV DNA 876 pg/ml Undetectable Undetectable UndetectableHBeAntigen Positive Negative Negative NegativeHBsAntigen Positive Positive Positive Positive

785

Tracheo-gastric fistula developing in a patient with esophageal stentafter esophagectomySandeep Singh, Madhukar Kaw, Mihir Patel and Harish Gagneja*. 1GIMedicine and Nutrition, M.D. Anderson Cancer Center, Houston, TX,United States.

Purpose: Tracheoesophageal fistula is not an uncommon complication ofesophageal malignancies. However tracheo-gastric fistula is a rare compli-cation of such malignancies.Methods: A 61 year old Caucasian male was initially diagnosed to havesquamous cell carcinoma of the esophagus. He underwent an Ivor-Lewisresection with a gastric pull up for curative intent in Sept, 1997. At the timeof the operation he was found to have subcarinal lymphadenopathy andreceived post-op radiation therapy for 6 weeks.

Subsequently, he underwent endoscopy for recurrent dysphagia whichrevealed an anastomotic stricture which was dilated multiple times over aperiod of 2 years. Repeated biopsies showed no evidence of tumor recur-rence. In Feb, 2000 he presented with food impaction and was found tohave a mass at the anastomosis. Biopsies confirmed recurrence of thesquamous cell carcinoma. Over the next 6 months, he developed worseningdysphagia and required multiple sessions of tumor ablation and dilatation.Finally, he underwent a stent placement with a Wilson Cook Z stent withantireflux valve in June, 2000. However, six months after the initial stentplacement he developed exuberant granulation tissue at the proximal end ofthe stent and underwent coated esophageal Wallstent placement. Threemonths after the placement of the second stent he developed persistentcough. A bronchoscopy showed a hole in his right main bronchus. Anupper endoscopy showed a opening in the gastric pouch corresponding tothe opening in the Rt mainstem bronchus consistent with a diagnosis oftracheo-gastric fistula. It was seen on the retroflexed view with the scopearound the plastic sheath of the antirelux valve of the Z stent. Unfortunatelyit was not amenable to endoscopic intervention because of the location. Thepatient was evaluated for bilateral bifurcated tracheal stents. He howeverdeclined further therapy and was referred to hospice.Conclusions: Tracheo-gastric fistula has been described as a complicationafter esophagectomy. Proposed mechanisms include tension at the sutureline and ischemia in surgical cases. If it is non malignant then surgicalresection with or without a muscle flap is a treatment option. This is in ouropinion the first case of a tracheo-gastric fistula developing in a patient witha esopahgeal stent.

786

Use of transparent overtube for endoscopic removal of a distallymigrated self expanding colonic metallic stentSandeep Singh, Madhukar Kaw, Mihir Patel and Harish Gagneja*. 1GIMedicine and Nutrition, M.D. Anderson Cancer Center, Houston, TX,United States.

Purpose: Endoscopic removal of a displaced self expanding colonic me-tallic stent (SEMS) is a safe option.Methods: A 65 year old male patient was diagnosed with sigmoid cancerwith metastasis to the liver. He presented to our institution for furthertreatment options and had obstructive symptoms. He underwent a colonos-copy which showed a obstructing mass in the rectosigmoid region. He

declined palliative surgery and underwent an enteral Wallstent placement.A week after the stent placement he developed rectal pain and inability topass flatus. Abdominal films showed distal migration of the stent to thelevel of the rectum. A emergent flexible sigmoidoscopy was performed andrevealed the stent had migrated distally in the rectum. A transparentovertube was then backloaded over the scope. The distal end of the stentwas grasped with a regular biopsy forceps and the stent was pulled downto the anal verge and was removed safely inside the overtube therebyprotecting the anorectum.Conclusions: SEMS are being increasingly used in patient with colorectalmalignancies. They can be used as a palliative measure in metastaticunresectable cases, as a bridge to surgery and neoadjuvant chemotherapyand in patients with acute large bowel obstruction for immediate relief.

Complications of stent placement include bleeding, perforation, mis-placement and migration. Stent migration is not an uncommon occurencewhich takes place in about 15–20 % of colonic stents. Factors that predis-pose to stent migration are extrinsic lesion, stricture dilation, small stentcaliber, poststenting radiation and chemotherapy. Many dislodged stentsare passed per rectum without the need to retrieve. Some stents such as theZ-stent and the Ultraflex stent can be removed digitally. Care should betaken while removing the Wallstent because trauma to fingertip can takeplace.

Stents can be removed by using a biopsy forceps and a transparentovertube as described. Care should be taken to avoid pulling on the ends ofa Wallstent excessively since the filaments can unravel. A plastic overtubecan protect the local tissues from traumatic injury.

787

Hyperammonemia of unknown etiology: a cause for episodic changein mental statusShailender Singh, MD, Hitender Jain, MD, Manzoor Rather, MD andAnthony Albornoz, MD*. 1Internal Medicine, Mercy Catholic MedicalCenter, Darby, PA, United States.

Purpose: Interesting case of episodic change in mental status.Methods: A 74-year old caucasian female with history of type II diabetesmellitus and coronary artery disease had multiple admissions over a oneyear period with changes in mental status. There was no history of alcoholabuse. Her neurological examination was always non-focal and rest of herphysical examination was unremarkable. All her routine laboratory inves-tigations were normal except for a high ammonia level (maximum up to243 mg/dl). Each time the improvement in her mental status correlated withthe reduction in serum ammonia level. Liver function and thyroid functiontests and comprehensive chemistry panel were within normal range as werecerebrospinal fluid studies. CT scan and MRI of brain were normal exceptfor some age appropriate changes. Ultrasound of the abdomen showedchanges suggestive of fatty liver and a liver biopsy confirmed the presenceof steatosis with no inflamation or fibrosis. Magnetic resonance angiogra-phy and doppler studies of the abdomen were negative for porto-systemicshunts. Serum and urine amino acid assays were normal. Patient showed agood response to treatment with branched chain amino acids and lactulose.Conclusions: The usual differential diagnosis for episodic change in men-tal status in adults include seizure, syncope, transient ischemic attacks andhypoglycemia. Hyperammonemia is another cause of change in mentalstatus in adults but is usually seen in association with alcoholic liver diseaseor occasionally in the presence of porto-systemic shunts. We were unableto find an etiology of hyperammonemia in our patient, but her clinicalcourse and response to protein restricted diet pointed towards ammoniarelated encephalopathy. Our case stresses the importance of suspectinghyperammonemia as a possible cause for episodic change in mental statuseven in non-alcoholic patients when the comprehensive work-up is nega-tive, since simple dietary measures may have a favourable outcome as seenin our case.

S246 Abstracts AJG – Vol. 96, No. 9, Suppl., 2001