Overview
Definition:
Gallstone ileus is a rare mechanical bowel obstruction that occurs when a gallstone erodes through the gallbladder wall and into the small intestine, creating a cholecystoenteric fistula and subsequently obstructing the bowel lumen
Enterolithotomy is the surgical procedure to remove the impacted gallstone from the intestine.
Epidemiology:
It is an uncommon complication of cholelithiasis, accounting for 1-4% of all mechanical small bowel obstructions
The incidence increases with age, with most patients being elderly females (peak incidence in the 7th to 8th decades)
Pre-existing comorbidities are common.
Clinical Significance:
Gallstone ileus is a surgical emergency associated with high morbidity and mortality (reported rates range from 12% to 30%)
Early recognition and prompt surgical intervention are critical for improving patient outcomes and reducing complications.
Clinical Presentation
Symptoms:
Abdominal pain, typically colicky and epigastric or periumbilical
Nausea and vomiting, often bilious
Abdominal distension
Constipation or obstipation (absence of flatus and stool)
Weight loss and malnutrition in chronic cases
Fever may suggest associated inflammation or infection.
Signs:
Distended abdomen with tympany
Tenderness on palpation, which may be diffuse or localized
Signs of dehydration and electrolyte imbalance
Absent bowel sounds or hyperactive high-pitched bowel sounds may be present initially
A palpable abdominal mass can sometimes be felt.
Diagnostic Criteria:
Diagnosis is primarily based on clinical suspicion combined with imaging findings
The Rigler's triad (pneumobilia, ectopic gallstone, and bowel obstruction) is pathognomonic but not always present
Confirmation often requires demonstration of the fistula and the obstructing stone on imaging.
Diagnostic Approach
History Taking:
Focus on symptoms of bowel obstruction, duration, and progression
Inquire about prior episodes of biliary colic, jaundice, or gallbladder disease
Assess for comorbidities such as diabetes, cardiovascular disease, and immunosuppression
Note any recent weight loss or changes in bowel habits.
Physical Examination:
Thorough abdominal examination for distension, tenderness, guarding, rigidity, and palpable masses
Assess for signs of dehydration (dry mucous membranes, decreased skin turgor, postural hypotension)
Perform a digital rectal examination to rule out distal obstruction or impaction.
Investigations:
Plain abdominal radiography may show signs of bowel obstruction (dilated loops of bowel, air-fluid levels) and may reveal calcified gallstones or pneumobilia
Computed tomography (CT) scan is the investigation of choice, demonstrating the gallstone, fistula, bowel obstruction, and extent of disease
it also helps in identifying other causes of obstruction
Ultrasound may show dilated bile ducts or gallstones but is less sensitive for gallstone ileus itself
Laboratory tests include complete blood count, electrolytes, renal function tests, and liver function tests to assess for dehydration, infection, and biliary involvement.
Differential Diagnosis:
Other causes of small bowel obstruction: adhesions, hernias, malignancy, intussusception, volvulus
Bouveret's syndrome (gastric outlet obstruction by a gallstone)
Inflammation of the bowel or appendix
Appendicular or diverticular abscess.
Management
Initial Management:
Immediate resuscitation with intravenous fluids to correct dehydration and electrolyte imbalances
Nasogastric tube insertion for decompression of the stomach and small bowel
Pain management with analgesics
Broad-spectrum antibiotics should be initiated if signs of infection are present.
Medical Management:
Primarily supportive care
Medical management alone is rarely effective for definitive treatment of gallstone ileus
It focuses on stabilizing the patient and managing complications.
Surgical Management:
Surgical intervention is indicated for all patients with confirmed gallstone ileus
The surgical approach aims to relieve the obstruction and, ideally, address the fistula
The primary surgical procedure involves enterolithotomy to remove the obstructing stone
Options for fistula management include: 1) Enterolithotomy alone (most common, especially in high-risk patients), allowing spontaneous closure of the fistula
2) Enterolithotomy with cholecystectomy and fistula repair (more definitive but increases operative time and risk, reserved for stable patients)
3) Laparoscopic approaches are being increasingly used but may be challenging due to inflammation and adhesions.
Supportive Care:
Close monitoring of vital signs, fluid balance, and electrolyte levels
Nutritional support, including parenteral nutrition if prolonged ileus or malabsorption is anticipated
Postoperative physiotherapy to prevent pulmonary complications
Pain control and wound care.
Complications
Early Complications:
Bowel ischemia and perforation at the site of obstruction
Sepsis
Anastomotic leak if enterotomy or resection is performed
Intra-abdominal abscess
Prolonged ileus
Dehiscence of enterotomy closure.
Late Complications:
Recurrent gallstone ileus if the fistula is not closed
Malabsorption and weight loss
Incisional hernia
Chronic abdominal pain
Stricture formation at the site of enterotomy or fistula.
Prevention Strategies:
Timely and appropriate management of symptomatic gallstones to prevent the formation of cholecystoenteric fistulas
Prophylactic cholecystectomy in asymptomatic patients with certain risk factors, although this is a debated topic
However, once gallstone ileus is diagnosed, the goal is to prevent complications through prompt and effective surgical management and meticulous postoperative care.
Prognosis
Factors Affecting Prognosis:
Patient's age and comorbidities significantly impact prognosis
Delay in diagnosis and treatment is associated with higher mortality
The extent of bowel involvement and the development of complications like perforation or sepsis worsen the outcome
The surgical approach chosen also plays a role.
Outcomes:
With prompt diagnosis and surgical management, mortality rates can be reduced
Patients who are surgically treated generally have a good outcome, especially if complications are avoided
However, elderly and infirm patients have a poorer prognosis.
Follow Up:
Postoperative follow-up typically involves monitoring for wound healing, return of bowel function, and signs of recurrent obstruction or malabsorption
Long-term follow-up may be indicated for patients with persistent symptoms or if a conservative approach to fistula management was chosen, to ensure spontaneous closure or to address late complications.
Key Points
Exam Focus:
Remember Rigler's triad: pneumobilia, ectopic gallstone, bowel obstruction
Gallstone ileus is a complication of cholelithiasis leading to mechanical obstruction via a cholecystoenteric fistula
Elderly females are most commonly affected
CT scan is the gold standard for diagnosis.
Clinical Pearls:
Suspect gallstone ileus in elderly patients with unexplained bowel obstruction and no history of prior abdominal surgery
Consider pneumobilia on imaging even in the absence of a visible stone within the bowel lumen
Enterolithotomy alone is often sufficient and safer in frail patients.
Common Mistakes:
Delayed diagnosis due to attributing symptoms to other common gastrointestinal issues
Inadequate resuscitation before surgery
Overtreatment in high-risk patients by opting for a two-stage procedure when a single-stage enterolithotomy would suffice
Failure to consider gallstone ileus in the differential diagnosis of bowel obstruction in the elderly.