Shiitake Mushroom As A Cause Of Bowel
Obsruction
Felicia Kong CY1, Subhathira Manohkaran2, and Kandasami Palayan3
1Medical Officer, General Surgery Department, Hospital Tuanku Ja’afar Seremban, Malaysia
ISSN: 0000-0000
filifele0023@gmail.com
Published 00 11 0000
2General Surgeon, General Surgery Department, Hospital Tuanku Ampuan Najihah, Malaysia
shubathira7@yahoo.com
3Professor of Surgery of International Medical University, Malaysia kanda@imu.edu.my
O R I G I NA L
Abstract
Shiitake mushrooms have been used in traditional Chinese medicine to prevent and treat several
ailments for centuries. Dried mushrooms are a popular ingredient in East Asian cuisine. Due to its
high insoluble fiber content, the undigested mushroom can act as a bezoar, and cause small bowel
obstruction. Bezoar-associated small bowel obstruction is rare and is usually found in patients
with a history of gastrointestinal surgery. We present a case of small bowel obstruction due to
mushroom bezoar in an elderly patient. Laparotomy and enterotomy were performed and a whole
piece of undigested shiitake mushroom obstruction the terminal ileum was extracted successfully.
Introduction
Most of the small-bowel obstructions are due to adhesions caused by a previous abdominal
surgery (1). Other causes include hernias, intussusceptions, tumors, and gallstone ileus. Bezoar-
induced small bowel obstructions are rare and reported to account for about 4% of all small
bowel obstructions (2). Phytobezoars are the most frequently observed type of bezoars, and they
consist of poorly digested fruit and vegetable fibers. Mushroom bezoar is a rare cause of small
bowel obstruction (3). There are no specific clinical features indicative of mushroom-induced
small bowel obstruction and diagnosis is often made at surgery. Delay in diagnosis can result in
a fatal outcome. Clinical awareness of the condition and a low threshold for using abdominal
computed tomography (CT) is essential for prompt diagnosis and treatment. We report a case of
small bowel obstruction caused by shiitake mushroom requiring surgical intervention.
Case Report
A 73-year-old woman with a history of diabetes mellitus and hypertension, presented with
progressively worsening abdominal pain and distension over four days. She also experienced
nausea, vomiting, and constipation. There was no history of altered bowel habits or surgery in the
past. There was no history of similar complaints in the past and the patient has been relatively
OPEN ACCESS
well. On examination, she did not appear distressed, and her vital signs were stable. The abdomen
Edited by
was distended but otherwise soft, and no mass was felt. Findings per rectal examination were
A.Hussain
insignificant. Her blood investigations revealed a white blood count of 12.8x103/µL, Hemoglobin
Submitted 30 Nov 2021
11.6 g/dl, platelet count of 300 x103/µL, Urea was 13.9 mmol/L and serum creatinine was 129
Accepted 04 Dec 2021
mol/L. Blood gas shows metabolic alkalosis (pH 7.51, HCO3 27.9, Base excess 4.8). An erect
Citation
abdominal x-ray demonstrated dilated small bowel. A contrast-enhanced computed tomography
Felicia Kong, Subhathira
of the abdomen revealed obstruction of the distal small bowel due to a suspicious mass. The
Manohkaran, Kandasami
patient was resuscitated and subjected to an urgent laparotomy.
Palayan. ShiitakeMush-
roomAsACauseOfBowel
Intraoperatively, the small bowel was dilated, and an obstructing intraluminal mass was noted
Obsruction:
in the ileum just proximal to the ileocecal junction Figure 2. There is no bowel ischemia or
BJOSS::2021:(1);35-38
perforation at the site of the mass. The mass was soft in consistency but fairly impacted in the
lumen of the bowel. A diagnosis of intestinal obstruction secondary to bezoar was made and
an enterotomy was performed Figure 3. A whole piece of undigested mushroom was found
impacting the lumen of the terminal ileum, and it was extracted successfully. The enterotomy
was closed primarily. Post-operative recovery was uneventful, and the patient was discharged on
the fourth post-operation.
(a)
(b)
Figure 1. shows CT abdomen (axial and coronal view). Arrow indicates the suspicious mass at
the distal ileum with dilatation of the small bowel. There is an abrupt transition at the narrowed
of terminal ileum due to obstruction in the small bowel.
Figure 2. Intraluminal mass at the terminal ileum with the transition zone
Figure 3. Whole piece of undigested shiitake mushroom (4cm x 3cm x 3cm) extracted through
enterotomy
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Discussion
Bezoars are aggregations of indigestible material that are usually formed in the stomach and
occasionally in the small intestine. Shiitake mushroom-related bezoar obstruction of the small
intestine is a rare occurrence (3). Shiitake mushroom is an important part of Asian cuisine and is
cherished as a healthy food with beneficial effects for health and treatment of diseases including
cancers (4). Mushrooms have gained increasing popularity and are being touted as a superfood
and are found in many different forms from powders to dried, fresh, or preserved format grocery
stores. The shiitake mushroom is full of dietary fiber and in the dried form it contains 49.1%
is dietary fiber and 82.9% of which is insoluble fibre (5). Dietary fiber is an important factor in
diet. It reduces the intestinal transit time of the food and increases fecal mass, which facilitates
defecation and prevents constipation. Given that mushrooms are rich in fiber when consumed
in uncut form, or large portions, the undigested fiber can act as a bezoar and may cause small
bowel obstruction. Previous gastric operations, difficulties associated with mastication, excessive
indulgence of foods with high fiber contents are common factors that are known to be associated
with bezoar-induced intestinal obstruction. The most common site for impaction in patients
without previous surgery is the terminal ileum, which correlates with the anatomical narrowest
part of the small bowel. Our patient did not have any previous surgery or gastrointestinal problems
in the past. However, she had poor dentition and the shiitake mushroom being fibrous, soft, and
slippery was probably swallowed without being properly chewed.
The clinical manifestation of bezoar-induced intestinal obstruction is variable, depending on the
site of impaction. The most common clinical features include abdominal pain, bloating, nausea and
vomiting. The diagnosis can be challenging because the manifestations are not easily distinguished
from other causes of small bowel obstruction (6). The diagnosis of small bowel obstruction must
be made accurately, that the site and cause of obstruction are determined before treatment
strategies are formulated. While most patients with adhesive small bowel obstruction resolve
spontaneously, delay in prompt management of bezoar-related small bowel obstruction may
result in bowel ischemia and fatal outcome. The diagnosis of small bowel obstruction is based
on a comprehensive approach that includes gathering clinical information, laboratory tests, and
radiological images. Although plain radiograph reveals a classical obstructive pattern of the bowel,
it fails to offer a clue to the etiology. Computerized tomographic scans of the abdomen have
become the preferred examination for the evaluation of small bowel obstruction as they can
provide valuable information on the cause of the obstruction (7). In addition, CT scans can help
detect signs of concomitant intestinal ischemia. The radiological features of small bowel bezoar
are typically described as intraluminal ovoid or rounded mottled-appearing mass, containing air
bubbles (8). With technological advances, endoscopic removal of bezoars has become an option
for the diagnosis and treatment of bezoars (9). However, the most reported endoscopic approach
has been limited to bezoars in the stomach and proximal small bowel.
Surgery is the standard treatment for small bowel obstruction due to bezoar (10). Generally,
the bezoar is impacted in the narrowest segment of the small bowel, which is at the terminal
ileum, just proximal to the ileocecal valve. At laparotomy, the entire length of the small and large
bowel must be examined thoroughly, and an enterotomy is performed to extract the bezoar.
Fragmentation and milking may be attempted if there is no evidence of bowel ischemia and the
bezoar is relatively soft and small. If fragmentation is attempted, it is important to ensure that
the entire bezoar is expelled to the large bowel and the integrity of the small bowel is preserved.
Segmental bowel resection and anastomosis may be required in presence of ischemia of the
bowel. While open laparotomy is widely considered the treatment of choice for small bowel
obstruction, the laparoscopic approach has in recent years gained increasing acceptance as a
treatment option (11) compared to open surgery, laparoscopy facilitates the earlier resumption
of diet and shorter hospital stay. Where feasible, laparoscopic extramural fragmentation of the
bezoar can be performed using atraumatic forceps and the bezoar can be milked into the caecum.
In our patient, uncertainties in the pathology and the extensive dilated intestinal loops made us
elect for open laparotomy rather than a laparoscopic approach.
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Conclusion
With the growing numbers of health-conscious consumers, shiitake mushrooms have become
an important source of dietary fiber. There must be a high index of suspicion bezoar induced
small bowel obstruction, especially in elderly patients with poor dentition. CT scans should be the
preferred imaging modality for early and accurate diagnosis. Surgical intervention should remain
as the mainstay of treatment for bezoar-induced small bowel obstruction.
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