Unexplained Abdominal Symptoms Research Articles

The Prevalence and Characteristics of Symptomatic Uncomplicated Diverticular Disease Among Asian Patients With Unexplained Abdominal Symptoms.

The precise incidence of symptomatic uncomplicated diverticular disease (SUDD) and its effects on the quality of life (QOL) remain unclear, particularly in Asian patients with right-sided SUDD. We assess the prevalence of SUDD and its impact on QOL in a real-world population. Five institutional cohorts of patients who received outpatient treatment for unexplained abdominal symptoms from January 15, 2020 to March 31, 2022, were included. All patients underwent colonoscopy. SUDD was defined as the presence of recurrent abdominal symptoms, particularly pain in the lower right or left quadrant lasting > 24 hours in patients with diverticulosis at the site of pain. The 36-item short-form health survey was used to assess QOL. Diverticula were identified in 108 of 361 patients. Among these 108 patients, 31% had SUDD, which was right-sided in 39% of cases. Of the 50 patients with right-sided diverticula, 36% had SUDD, as did 15 of 35 patients with left-sided diverticula (43%). Among the 33 patients with SUDD, diverticula were right-sided, left-sided, and bilateral in 39%, 45%, and 15% of patients, respectively. Diarrhea was more frequent in the SUDD group than in the non-SUDD group. Patients with SUDD had significantly lower physical, mental, and role/social component scores than those without SUDD. It is important to recognize that patients with SUDD account for as high as 31% of outpatients with unexplained abdominal symptoms; these patients have diarrhea and a low QOL. The presence of right-sided SUDD was characteristic of Asian patients.

Thrombotic thrombocytopenic purpura-adifferential diagnostic challenge in an emergency

Thrombotic thrombocytopenic purpura (TTP), which comprises thrombocytopenia, elevated lactate dehydrogenase levels, and anemia in the combination of organ involvement, is a rare but life-threatening condition associated with an extremely high lethality in the acute phase if left untreated. Using the example of a 49-year-old woman admitted to the hospital with unexplained abdominal symptoms and subfebrile temperatures, recommendations for the emergency situation are presented. Increased awareness of the disease and targeted further diagnostics with determination of the PLASMIC score or ADAMTS13 activity may lead directly to diagnosis of TTP; delayed diagnosis is usually associated with secondary complications.

High Discovery Rate of Duodenal and Gastric Eosinophilia in Patients With Unexplained Moderate–Severe Abdominal Symptoms: A Prospective US Multisite Study

High Discovery Rate of Duodenal and Gastric Eosinophilia in Patients With Unexplained Moderate–Severe Abdominal Symptoms: A Prospective US Multisite Study

S3732 A Unique Manifestation of Tuberculosis in the Gut

Introduction: Abdominal manifestations of tuberculosis (TB) can involve the peritoneum, gastric body, intestinal tract, pancreas, perianal region, hepatobiliary region, and surrounding lymph nodes in patients with associated risk factors. We present a patient with known TB exposure and a gastric mass with associated lymphadenopathy (LAD), later determined to be secondary to gastric tuberculosis. Case Description/Methods: An 18 year old female with no past medical history presented with several months of upper abdominal pain exacerbated by deep breathing. A prior esophagogastroduodenoscopy (EGD) revealed a submucosal gastric ulcer (1), and further evaluation with an EGD and endoscopic ultrasound (EUS) revealed a peri-gastric mass with retroperitoneal and portocaval LAD (2). Fine needle aspiration (FNA) of the mass revealed granulomatous inflammation with focal necrosis (3) and rare acid fast bacilli seen on Fite stain (4). Further history on follow up revealed a close household contact had recently tested positive for TB. The patient was started on full treatment with Rifampin, Isoniazid, Pyrazinamide, and Ethambutol (RIPE) for gastric TB, with improvement in symptoms noted on follow up. A repeat EGD with EUS was performed 7 months after the initial, with observed improvement in retroperitoneal LAD and no organisms seen on FNA. (Figure) Discussion: This case illustrates a unique presentation of gastric TB in a patient, later determined to have been exposed to a close contact. The presenting symptom of non-remitting abdominal pain along with prior endoscopic findings of a submucosal gastric ulcer prompted further evaluation, which led to the histologically confirmed diagnosis of gastric TB and the initiation of appropriate treatment. Gastrointestinal (GI) tract involvement of TB occurs in about 11% of cases, and is associated with concomitant pulmonary TB infection in only about 25% of cases. Mycobacterium tuberculosis is thought to infiltrate the GI tract by adhering to submucosal lymphoid tissue, with caseous necrosis leading to ulceration over 2-4 weeks. Diagnostic findings include circumferential ulceration surrounded by inflammation with submucosal granulomas seen on biopsy, as seen in this case. Patients often clinically improve after treatment with RIPE, though surgical management is warranted when complications exist. GI manifestations of TB should be considered in patients with positive risk factors and unexplained persistent abdominal symptoms, with treatment initiated as soon as the diagnosis is confirmed.Figure 1.: 1) Gastric cardia ulcer seen on EGD 2) Peri-gastric lymphadenopathy seen on EUS 3) 10x Hematoxylin & Eosin (H&E) stain of gastric tissue showing granulomatous inflammation 4) 60x Fite stain of gastric tissue showing acid fast bacilli.

Celiac disease may be rare among children in South China.

ObjectiveThe prevalence of celiac disease (CD) varies geographically and ethnically; however, the prevalence among children in South China remains unknown. We therefore determined the occurrence of CD among Chinese children in South China.MethodsSerum samples were collected from children and assessed for anti-tissue transglutaminase IgA antibodies (anti-tTG-IgA) and total IgA. Anti-tTG-IgA+ participants underwent human leukocyte antigen (HLA) DQ2/DQ8 determination. Samples with serum total IgA <0.05 g/L were also analyzed for anti-tTG-IgG, and for HLA-DQ2/DQ8 if the values were above borderline. Participants who were anti-tTG-IgA/IgG+ and HLA-DQ2+ and/or HLA-DQ8+ underwent small bowel biopsy.ResultsA total of 8794 children were enrolled, of whom 479 had chronic unexplained abdominal symptoms. Three (0.034%) children were anti-tTG-IgA+ and ten (0.114%) had serum total IgA <0.05 g/L, all of whom were anti-tTG-IgG−. The three positive children were all HLA-DQ2+ and/or HLA-DQ8+. Two underwent gastroscopy, and histopathology of small intestinal biopsy showed duodenal villous blunting in one and increased intraepithelial lymphocytes in the other, neither consistent with a diagnosis of CD.ConclusionOur study showed a prevalence of CD autoimmunity of 0.034% and failed to identify any cases of CD, suggesting a low prevalence of CD among children in South China.

Acquired diaphragmatic hernia after hepatectomy and liver transplantation in adults and children: A case series and literature review.

Backgrounds/AimsAcquired diaphragmatic hernia is a rare complication following liver surgery in adult and pediatric patients. This study aims to describe main features occurring in adult and pediatric patients after liver surgery and report an up-date review of the literature.MethodsAll adult and pediatric patients who were diagnosed with postoperative acquired diaphragmatic hernia in Lyon and Marseille University Hospitals were included in this study. Diagnosis, clinical, radiologic, and therapeutic data were analysed retrospectively from medical papers and/or electronic records.ResultsThirteen adults with a median age of 50 years (range, 30–67 years) and 5 children aged 2.4 years (range, 0.9–4 years) were diagnosed with acquired diaphragmatic hernia after a median time of 65.1 (range, 1.8–244.7) and 2 (range, 0.33–10.9) months, respectively, following surgeries (5 live-donor right hepatectomies, 5 right and 1 left hepatectomies for tumors and cysts, and 2 whole liver transplantations in adults; and 5 liver transplantations with left lateral section in children). Eleven patients presented digestive and/or thoracic symptoms whereas seven were asymptomatic and diagnosed by routine imaging follow-up. All patients were re-operated with a median delay of 2.4 months (range, 0–25.3 months) for adults and 1 day (range, 0–2 days) for children. Two recurrences resulted in a secondary surgical repair.ConclusionsAcquired diaphragmatic hernia is a rare and potentially serious event after liver surgery. Recognition and surgical repair of this particular complication should be considered in the setting of unexplained abdominal and/or thoracic symptoms. Preventive measures should be taken intraoperatively.

ADHESIONS ARE NOT ALWAYS THE ENEMY: POUCH VOLVULUS

Abstract Introduction Proctocolectomy with ileal pouch anal anastomosis (IPAA) was introduced over 40 years ago, prior to the era of laparoscopy. Since then, minimally invasive surgery (MIS) techniques have been applied to pelvic pouch surgery. One advantage of MIS is the reduction in adhesion-related complications. However, the lack of adhesions may result in a different set of complications. Specifically, when the pouch is not adherent in the pelvis, pouch volvulus can occur around the mesenteric axis. The aim of this study was to describe our experience with pelvic pouch volvulus. Methods Our prospectively maintained pelvic pouch registry and our enterprise wide electronic medical record were queried for keyword combinations of “pouch volvulus” between 1994 and 2020. Pouch volvulus was defined as torsion of the ileal pouch on its own mesenteric axis or around small bowel while maintaining the proper orientation of the ileo-anal anastomosis. Patients with pouches constructed with twisted mesenteric axis from ill-aligned anastomoses were excluded. Data for these patients was collected from the pouch registry and additional chart review. Results We identified 17 patients with pouch volvulus; of these, 11 patients did not meet our selection criteria and were excluded. Of the 6 patients (5 female; median age 25 range 20–33 yr at time of volvulus surgery) with true volvulus, the diagnosis at IPAA was ulcerative colitis (n=5) and Lynch syndrome with a rectal cancer. All pelvic pouches were constructed with MIS techniques, including standard laparoscopy (n=4) and single incision laparoscopic technique (n=2). All 6 patients presented with diffuse abdominal pain and abdominal distention. The average time from pouch construction to pouch volvulus was 2.5 years (range: 5.2 – 97.5 months). Computed tomography with or without rectal contrast was the initial diagnostic test in 4/6 with findings highly suspicious for pouch volvulus. Surgery was performed urgently in 5/6 of patients; all 6 had open surgery. At reoperation, all had minimal adhesions and a gap between the pouch mesentery and the retroperitoneum. Interventions included pouch-pexy (n=3), closure of gap between pouch and sacrum (n=2), and pouch excision and ileostomy (n=1). At a median of 9 months (IQR: 4–97) of follow up, pouch survival was 83%; functional outcomes included mild fecal incontinence (n=1) and paradox requiring intermittent pouch intubation for stool evacuation (n=1). Conclusions Pelvic pouches constructed by minimally invasive techniques may be at risk for pouch volvulus due to minimal adhesions. Surgeons should have a high index of suspicion for patients with unexplained abdominal pain, distension, and other obstructive symptoms. Cross-sectional imaging with rectal contrast, may help clarify the diagnosis. Immediate surgical care can allow for pouch salvage.

Studies on Celiac Disease in UAE

Celiac disease occurs in about 1% of people in most populations. The time taken to make the diagnosis may go to years or more than 10 years. The disease affects people of all ages. The disease has many clinical manifestations, ranging from severe malabsorption to minimally symptomatic or non-symptomatic presentation. Presentations can be, persistent unexplained abdominal or gastrointestinal symptoms, failure of growth, prolonged fatigue, unexpected weight loss, severe or persistent mouth ulcers, unexplained iron, Vitamin B12, or folate deficiency, type 1 diabetes, autoimmune thyroid disease, irritable bowel syndrome. Other presentations can be, infertility, epilepsy, arthritis, and hypothyroidism. 2 studies done in UAE in pre marriage adults showed a prevalence of 2.3% in our practice in our centre ACDS centre we came across a variety of presentations including, reflux esophagitis, anemia,allergy,hypothyroidism,epilepsy,after bariatric surgery,transaminitis. Over 150 cases of celiac disease seen over the last 7 years the majority of cases were missed by clinicians. Awareness campaigns are needed to raise awareness.

Diarrhoea and diabetes

Diarrhoea and diabetes

A single-center audit of the indications and clinical impact of prolonged ambulatory small intestinal manometry.

Small bowel manometry is a diagnostic test available only in a few specialized referral centers. Its exact place in the management of refractory symptoms is controversial. The records of all patients who underwent 24-hour ambulatory duodenojejunal manometry over a 6-year period were retrospectively reviewed. We studied the clinical indications for small bowel manometry, and reviewed the impact of manometric findings on the clinical outcome. One hundred and forty-six studies were performed in 137 patients (46M, 91F) with a mean age of 44.9±15.7years. Mean follow-up duration was 15.1±22.6months. Appropriate endoscopic, radiological and gastric scintigraphy studies were performed in all patients prior to small bowel manometry. Criteria for abnormal motor activity were based on Bharucha's classification. The indications for small bowel manometry were chronic abdominal pain (n=43), slow-transit constipation (n=17), refractory gastroparesis (n=16), chronic diarrhea (n=7), recurrent episodes of subocclusion (n=16), postsurgical evaluation (n=36), suspicion of gut involvement in systemic disease (n=9), and unexplained nausea (n=2). The most common finding was a normal 24-hour ambulatory small bowel manometry (n=113). Thirty-three studies yielded abnormal findings which included extrinsic neuropathy (n=6), intrinsic neuropathy (n=18), intestinal myopathy (n=2), and subocclusion (n=7). Ambulatory small bowel manometry excluded a generalized motility disorder in 77% and had a significant impact on the subsequent clinical course in 23%. Ambulatory small bowel manometry is a useful and safe diagnostic tool to complement traditional investigative modalities in patients with severe unexplained abdominal symptoms.

Celiac disease in non-clinical populations of Japan.

Celiac disease is a chronic autoimmune enteropathy caused by gluten ingestion. While its prevalence in Western countries is reported to be as high as 1%, the prevalence has not been evaluated in a large-scale study of a Japanese population. The aim of our study was to clarify the possible presence of celiac disease in a Japanese non-clinical population as well as in patients showing symptoms suggestive of the disease. Serum samples were collected from 2008 non-clinical adults and 47 patients with chronic unexplained abdominal symptoms between April 2014 and June 2016. The anti-tissue transglutaminase (TTG) immunoglobulin A antibody titer was determined as a screening test for celiac disease in all subjects, and individuals with a value of >2U/mL subsequently underwent testing for the presence of serum endomysial IgA antibody (EMA) as confirmation. Those testing positive for EMA or with a high concentration (>10U/mL) of TTG were further investigated by histopathological examinations of duodenal mucosal biopsy specimens and HLA typing tests. Of the 2008 non-clinical adults from whom serum samples were collected, 161 tested positive for TTG, and all tested negative for EMA. Four subjects who had a high TTG titer were invited to undergo confirmatory testing, and the histopathological results confirmed the presence of celiac disease in only a single case (0.05%). Of the 47 symptomatic patients, one (2.1%) was found to have a high TTG titer and was diagnosed with celiac disease based on duodenal histopathological findings. The presence of celiac disease in a non-clinical Japanese population was low at 0.05% and was rarely found in patients with unexplained chronic abdominal symptoms.

Portal vein thrombosis following laparoscopic sleeve gastrectomy: A rare case report

Introduction: Portal vein thrombosis (PVt) is a relatively uncommon complication after sleeve gastrectomy. case report: A 33-year-old female underwent an uncomplicated laparoscopic sleeve gastrectomy for the treatment of morbid obesity, and presented on postoperative day14 with epigastric pain. computed tomography scan revealed left portal vein thrombosis. she promptly improved after initiation of lowmolecular-weight heparin and was discharged on hospital day-5 with oral warfarin. conclusion: Although uncommon, PVt should be included in the differential diagnosis for unexplained abdominal symptoms after laparoscopic sleeve gastrectomy.

Fructose Malabsorption in Patients With Irritable Bowel Syndrome-like Symptoms: What Is the Role in the Pathogenesis and Clinical Implication?

Article: Unclear abdominal discomfort: pivotal role of carbohydrate malabsorption Goebel-Stengel M, Stengel A, Schmidtmann M, van der Voort I, Kobelt P, Mönnikes H.

Screening colonoscopy in the initial workup of bariatric surgery patients: guidelines are needed

Cancer is one of the most common causes of death among morbidly obese individuals. Obese individuals have a well-documented increased risk of colon cancer. No guidelines are available for the workup of bariatric surgery patients in relation to colon cancer. The indications for screening colonoscopy at the Bariatric and Metabolic Institute Abu Dhabi (BMI Abu Dhabi) include all patients older than 50 years [40 years if patients are United Arab Emirates (UAE) nationals] with unexplained abdominal symptoms, anemia of unknown cause, or a family or personal history of colonic pathology. This study retrospectively reviewed the charts of all the patients who had colonoscopy during the period January 2009 to January 2013. The patients were divided into two groups: group A [patients with a body mass index (BMI) > 30 kg/m(2)] and group B (patients with a BMI < 30 kg/m(2)). The demographics and the prevalence of polyps and cancer in the two groups were compared. During the study period, 341 colonoscopies were performed: 137 for patients with a BMI higher than 30 kg/m(2) (mean age, 44 years) and 204 for patients with a BMI lower than 30 kg/m(2) (mean age, 46 years) (P > 0.05). The overall prevalence of adenomatous polyps was 6.74 % and that of cancer was 1.75 %. Further analysis showed that the prevalences of adenomatous polyps and cancer were respectively 12.4 and 2.1 % for the patients with a BMI higher than 30 kg/m(2), whereas the prevalences were respectively 2.9 and 0.9 % for the patients with BMI lower than 30 kg/m(2) (P < 0.001). The risk for the development of colonic adenomatous polyps and cancer is high among young obese individuals in the Middle East. Guidelines are needed to establish criteria for screening in this group of individuals.

Tuberculous peritonitis in pregnancy: a case report

IntroductionTuberculous peritonitis is one of the least common forms of extrapulmonary tuberculosis. In the literature, few cases in pregnancy have been previously published. Tuberculous peritonitis in pregnancy is a diagnostic challenge, especially in the absence of lung involvement. It mimics other diseases and clinical presentation is usually non-specific, which may lead to diagnostic delay and development of complications.Case presentationWe report here a new case of tuberculous peritonitis that occurred in a 31-year-old Caucasian pregnant woman at 22 weeks' gestation. She was complaining of abdominal pain, nausea and vomiting. These symptoms appeared 6 months prior to presentation. Initially, they were attributed to pregnancy, but they progressively became more severe during subsequent weeks. A laparoscopy showed the presence of yellow-white nodules on the peritoneal surface and a biopsy demonstrated caseous necrotic granuloma. She made a good physical recovery after being placed on antituberculous chemotherapy and gave birth to a healthy male neonate of 3100g at 37 weeks' gestation by vaginal delivery.ConclusionsExtreme vigilance should be used when dealing with unexplained abdominal symptoms to ensure timely diagnosis of tuberculous peritonitis. Diagnosis often requires a histopathological examination. In these patients early diagnosis with early antituberculous therapy are essential to prevent obstetrical and neonatal morbidity.

Focal epilepsy with ictal abdominal pain: a case report

Focal epilepsy with ictal abdominal pain is an unusual partial epilepsy characterized by paroxysmal episodes of abdominal or visceral pain, disturbance of awareness and electroencephalographic abnormalities. We describe a new case of ictal abdominal pain in which gastrointestinal complaints were the only manifestation of seizures and review the previously described pediatric patients. In our patient clinical findings, ictal EEG abnormalities, and a good response to antiepileptic drugs allowed us to make a diagnosis of focal epilepsy with ictal abdominal pain. This is a rare epileptic phenomenon that should be suspected in patients with unexplained paroxysmal abdominal pain and migraine-like symptoms. We suggest that, after the exclusion of more common etiologies, focal epilepsy with ictal abdominal pain should be considered in patients with paroxysmal abdominal pain and ictal EEG abnormalities.

The influence of respiration on criteria for transabdominal duplex examination of the splanchnic arteries in patients with suspected chronic splanchnic ischemia

Duplex ultrasound imaging of the mesenteric vessels is often used as a first diagnostic tool to evaluate the mesenteric circulation in patients with unexplained chronic abdominal symptoms. Several studies on duplex criteria have been published; however, most studies are small and included not exclusively patients with symptoms suggestive of chronic mesenteric syndrome (CMS). This study evaluated the contribution of respiration-monitored duplex ultrasound imaging in the diagnosis of stenosis or occlusion of the mesenteric arteries in patients suspected of CMS and thereby improves the definition of the criteria for stenosis. Between 1999 and 2007, 779 consecutive patients presented to our tertiary referral center for evaluation andtreatment of CMS. Mesenteric artery duplex ultrasound imaging and angiography of the abdominal aorta and itsbranches were performed in 324 patients. Angiography was considered the gold standard for verifying the presence orabsence of arterial pathology. Results from duplex imaging and angiography were compared to determine the optimalduplex criteria for stenosis. In addition, the contribution of expiration and inspiration on duplex imaging and angiography were established. Significantly higher peak systolic and end-diastolic velocities were found in the celiac artery (CA) and superior mesenteric artery (SMA) during expiration than during inspiration. Receiver operating characteristic curve analyses found respiration-dependent cutoff values for CA and SMA stenosis. The values corresponding with the highest accuracy (minimal false-negative and false-positive results) were determined. Peak systolic velocities cutoff points during expiration and inspiration were 280 and 272 cm/s, respectively, for the CA and 268 and 205 cm/s for the SMA. The end-diastolic velocity cutoff points during expiration and inspiration were 57 and 84 cm/s, respectively, for the CA and 101 and 52cm/s for the SMA. Sensitivity for different duplex parameters in detecting mesenteric stenosis was 66% to 78% and specificity was 77% to 86%. This study proposes new criteria related to respiration for duplex ultrasound imaging of the mesenteric arteries in patients with symptoms suggestive of CMS. It emphasizes the importance of taking into account the effect of respiration on duplex parameters. The lower sensitivity and specificity in our study compared with other studies puts into perspective the position of duplex imaging in the work-up of patients with suspected CMS. Duplex results should be used as a guide, with a low threshold giving a higher negative predictive value and, consequently, a lower positive predictive value.

Abdominal tuberculosis: a retrospective review of cases presenting to a UK district hospital

Peterborough has one of the highest rates of tuberculosis in the East of England; ∼40% of TB treated locally is extra-pulmonary. All adults diagnosed with abdominal tuberculosis (ATB) between January 2008 and September 2011 in Peterborough Hospitals were retrospectively evaluated with regard to their clinical history, investigation, management and outcomes. In total, 17 patients diagnosed with ATB were reviewed. All the patients were from (or descended from) high-risk ethnic groups. Four had co-existing pulmonary TB. Intestinal and peritoneal TB were the most common findings. The most common clinical manifestations included abdominal pain (71%), weight loss (59%), diarrhoea (47%) and pyrexia (41%). Fifteen patients had samples sent for microbiological investigation; 1 (6%) was smear positive and 9 (53%) were culture positive. Two (12%) were isoniazid resistant. No rifampicin resistance was detected. Anti-tuberculous therapy was given for 6-12 months. In total, 16 (94%) patients completed the treatment; 1 patient died prior to regime completion (crude mortality: 6%). There was one reported case of pyrazinamide intolerance and two episodes of isoniazid intolerance. ATB is a diagnostic challenge, especially in absence of lung involvement. It mimics other diseases and clinical presentation is usually non-specific, which may lead to diagnostic delay and development of complications. Extreme vigilance should be used when dealing with unexplained abdominal symptoms to ensure timely diagnosis of ATB. Early diagnosis with early anti-tuberculous therapy and surgical treatment are essential to ensure as positive an outcome as possible.

Superior Mesenteric Venous Thrombosis after Laparoscopic Exploration for Small Bowel Obstruction

Mesenteric venous thrombosis is a rare cause of intestinal ischemia which is potentially life-threatening because it can lead to intestinal infarction. Mesenteric venous thrombosis rarely develops after abdominal surgery and is usually associated with coagulation disorders. Associated symptoms are generally subtle or nonspecific, often resulting in delayed diagnosis. A 68-year-old woman underwent laparoscopic exploration for small bowel obstruction, secondary to adhesions. During the procedure, an intestinal perforation was identified and repaired. Postoperatively, the abdominal pain persisted and repeat exploration was undertaken. At repeat exploration, a perforation was identified in the small bowel with a surrounding abscess. After the second operation, the abdominal pain improved but anorexia persisted. Contrast enhanced abdominal computed tomography was performed which revealed superior mesenteric venous thrombosis. Anticoagulation therapy with heparin was started immediately and the thrombus resolved over the next 6 days. Although rare, this complication must be considered in patients after abdominal surgery with unexplained abdominal symptoms.

Improving diagnosis of adult-type hypolactasia in patients with abdominal complaints

Adult-type hypolactasia is caused by genetic lactase non-persistence. It is the most common cause of lactose intolerance, which results in gastrointestinal symptoms after ingestion of dairy products. Currently, lactose intolerance is investigated by the hydrogen breath test (HBT), which is considered the preferred diagnostic test. Adult-type hypolactasia may also be diagnosed by genotyping. The single nucleotide polymorphism -13910C>T, which is located upstream of the lactase gene (LCT), is tightly associated with lactase persistence. Several other variants, mostly in non-European populations, can also lead to lactase persistence. This study investigated the accuracy of a modified, recently proposed algorithm which includes genotyping for the diagnosis of adult-type hypolactasia in a patient population with unexplained abdominal complaints. In 126 patients with unexplained abdominal symptoms or who were suspected to have adult-type hypolactasia, LCT genotyping by melting curve analysis on a LightCycler was performed. Those patients with CC(-13910) genotype (indicating loss of lactase expression) were directly referred to a dietician for a lactose-free diet. Those identified as CT(-13910) or TT(-13910) genotype underwent a HBT. Those who tested positive for hydrogen were also referred to a dietician for a lactose-free diet. The response to diet modification was recorded. Genotype prevalences were: CC(-13910): 43 (34.1%); CT(-13910): 48 (38.1%); TT(-13910): 33 (26.2%); TG-13915: 2 (1.6%). Eleven of 48 (23%) patients with CT(-13910)-genotype and 1/33 (3%) patients with TT(-13910)-genotype had a positive hydrogen breath test. They all improved after a lactose-free diet. Four of 43 (9%) patients with CC(-13910)-genotype still had symptoms after a lactose-free diet. The results show that lactase-genotype testing can be used as a first step to diagnose lactose intolerance in a patient population with unexplained abdominal complaints. It accurately identifies the group of patients sensitive to lactose, those who need further breath testing and those in whom adult-type hypolactasia can be excluded with high probability without performing a HBT. This algorithm would save hydrogen breath testing in more than 50% of the patients who present with unexplained abdominal symptoms.