Teaching Case

A 53 -year-old man presented with hematemesis, dark-coloured stools, vomiting, severe colicky pain, and progressive abdominal distension for three days. His blood pressure was 90/60 mmHg.

Serial hemogram showed drop in haemoglobin. Serum electrophoretic tests showed a monoclonal band of immunoglobulin G kappa, and free serum Kappa- 25557 mg/ L.

Plain CT shows dilated proximal jejunal loops with intraluminal haemorrhage.

On contrast-enhanced CT, The following findings were present,

1. Intraluminal haemorrhage, dilatation of jejunal loops with thickened valvulae conniventes and focal circumferential wall thickening of the jejunum.

2. There is submucosal oedema with enhancing wall and mucosa representing Halo sign.

3. The distal ileal loops are collapsed.

4. On CT angiography, there is the normal opacification of the major vessels and mesenteric vessels.

Background

Amyloidosis -  deposition of an abnormal fibrillar protein -amyloid in the extracellular space, causing structural and functional tissue damage. Amyloidosis can be hereditary or acquired, and localized or systemic [1].
Primary (AL) amyloidosis is common, and only 15% of these patients have multiple myeloma [1]. Secondary (AA) amyloidosis is associated with chronic inflammatory, infectious, and neoplastic disorders [1].

In amyloidosis, dysmotility and bowel dilatation is postulated to be due to amyloid deposition within the muscularis propria or myenteric plexus.

Clinical Perspective

Clinically intestinal amyloidosis may remain asymptomatic or can manifest as abdominal pain, a change of bowel habits, spontaneous bowel perforation, and GI bleeding. Common symptoms include weakness and fatigue [2]. Intestinal pseudo-obstruction is characterized by a clinical picture suggestive of mechanical obstruction in the absence of demonstrable evidence of such an obstruction in the intestine. Imaging plays a major role in such cases to reveal the underlying cause

Imaging Perspective

To assess bowel wall haemorrhage Plain CT is essential. Initial non-contrast CT images demonstrate the presence of intramural haemorrhage.

On CECT, common findings of small intestinal amyloidosis are dilatation of several small bowel loops, thickening of small bowel folds, and submucosal oedema (seen as a double halo) caused by ischemia as a result of vascular accumulation [1,3]. Hyperdense heterogenous luminal contents representing haemorrhage is uncommon. It’s mandatory to give intravenous contrast for demonstrating the patency of vessels and bowel wall enhancement.

Ultrasonography findings are non-specific such as small-bowel dilatation, symmetric bowel wall thickening, and mesenteric adenopathy. Barium enema findings include regular thickening of the folds, jejunization of the ileum, a granular mucosal pattern, and tiny polypoid protrusions [3].

Outcome

First-line treatment is combination chemotherapy with melphalan, dexamethasone, and hematopoietic stem cell transplantation. Proteasome inhibitor-based regimens are the preferred choice due to better response rates and outcomes [4].
The prognosis for patients with focal intestinal amyloidosis is generally good. Diffuse small intestinal involvement by amyloid infiltration into smooth muscle causes irreversible myopathy leading to intestinal pseudo-obstruction which poorly responds to medical treatment and carries a poor prognosis [5].
In this case, dilated jejunal loops with intraluminal haemorrhage were resected, and jejuno-jejunal anastomosis was done. Post-operative period was uneventful.

Take-Home Message / Teaching Points

Radiological findings are non-specific in small bowel amyloidosis. When evaluated carefully with background of multiple myeloma or plasma cell dyscrasia, one can raise the possibility of amyloidosis, and suggest further tissue biopsy for definitive diagnosis.

Characteristic imaging findings of bowel amyloidosis are hyperdense jejunal wall on plain CT,  thickened valvulae conniventes,  segmental hyper-enhancing bowel wall with halo sign, normal CT angiography/venography and intraluminal bleed.

Written informed patient consent for publication has been obtained.