Brown bowel syndrome: a rare and often overlooked complication of intestinal atresia.

Dear Editor,

I read with great interest the recent article by Akkoyun et al.[1] Interestingly, one rare complication of intestinal atresia that is often overlooked is “Brown bowel syndrome” (BBS).

The pathogenesis of BBS involves the deposition of lipofuscin in the intestinal tunica mucularis in paranuclear vacuoles.[2] It usually affects the large intestinal wall, but can affect the small intestine also especially the jejunum. The appendix may also be affected. Lipofuscin deposition may also be seen in the arteries in the muscularis propria. The brownish discoloration is secondary to the release of lipofuscin from the degenerated mitochondria.[3] The liopofuscin deposits usually spare the actual mucosal lining. BBS may affect any age. Cases as young as 11 years of age have been reported. Vitamin E deficiency is typically seen in BBS. A consequent mitochondrial myopathy develops. Intestinal malabsorption is further accentuated as a result of atony and decreased peristalsis in the intestinal wall. Simultaneous deficiency of vitamin D is usually seen. Thiamine deficiency as well as vitamin A deficiency is also fairly common.

Patients with a long history of ethanol abuse are more likely to develop BBS. BBS has also been reported recently by Connolly et al., in patients with Cohn's disease.[4] Rarely, BBS may occur secondary to an intestinal malignancy. For instance, it has been reported in conjunction with jejunal carcinomas. Intestinal atresia especially “jejunal atresia” may also lead to the development of BBS.[3] Progressive accentuation of jejunal dilatation is seen in these cases. BBS has also been reported to develop secondary to chronic esophagitis.[2] Associated esophageal strictures may also contribute to the evolution and progression of BBS. BBS has also been reported recently as a late complication of “jejunoileal bypass” surgery.[5]

Patients usually present with severe malnutrition and muscle wasting. Severe cachexia may be present in chronic cases. Chronic diarrhea especially steatorrhea is usually present.[6] Abdominal pain and distension may be present simultaneously. Severe vomiting may accompany the above features. This may be marked in patients with significant colonic dilatation. Signs suggestive of toxic megacolon may be present rarely.[2] Dehydration is usually elicited on physical examination. Altered neurologic function may be present in some patients. For instance, signs and symptoms consistent with peripheral neuropathies may be present. Signs and symptoms consistent with myopathy may develop in severe cases.[7]

Rarely patients may present with an acute abdomen that on further evaluation leads to a diagnosis of BBS.[5] The acute abdomen may be secondary to the development of an acute intussusception. Rarely, patients may develop decreased tone of the internal sphincter also. This was recently reported by Waldron et al.[7] Rarely, severe lower gastrointestinal bleeding may occur secondary to BBS. This was recently reported by Hurley et al.[8] Cardiac deposition of lipofuscin may also occur resulting in cardiac symptoms. Simultaneous osteomalacia and secondary hyperparathyroidism may also be present.[4]

Barium follow through studies are usually recommended initially. These studies typically demonstrate delayed transit through the affected intestinal portion. Proximal intestinal dilatation is seen simultaneously. Transmural intestinal biopsies stain with the “Fontana-Masson” stain indicating the presence of lipofuscin.[4] The deposits also stain with periodic acid-Schiff. Deposits are seen both in the longitudinal as well as the circular intestinal musculature. Vitamin E levels may be undetectable in severe cases.[5] Concurrent selenium deficiency is seen in most patients. Liver function tests (LFTs) may be altered and prothrombin time (PT) may be elevated. Peripheral blood examination reveals highly fragile red blood cells (RBCs).[7] Muscle biopsies in severe cases reveal fatty replacement with concurrent myopathic changes. Stool cultures are typically negative. Rarely, mesenteric lymphadenopathy may develop in association with BBS. In these cases, the lymphatic reticuloendothelial cells typically exhibit lipofuscin deposits.[2] Lipofuscin deposits have also been reported in the eye and thyroid tissue at the same time as the BBS. The urinary bladder and the prostate gland are also prone to develop simultaneous lipofuscin deposition. This was recently reported by Braunstein et al.

Vitamin E therapy should be initiated as soon as the diagnosis is made. Parenteral vitamin E supplementation may be necessary in some cases.[6] Surgical intervention such as “subtotal colectomy” may be necessary in certain patients. Limited intestinal resection with “end-to-end anastomosis” is necessary in patients with a history of intestinal atresia.[910] Complete or partial resolution of symptoms is seen in patients who develop myopathy. Intestinal transplantation may be needed in severe cases of BBS. BBS may rarely be fatal. As is obvious from the above discussion BBS is a rare complication of intestinal atresia and should be watched out for in these patients.