Case: A 35 year-old, overweight female presents to the emergency room with five days of left lower quadrant abdominal pain. The pain is 10/10 in severity and accompanied by nausea, bloating, and loss of appetite.
Diverticulosis, the presence of small colonic outpouchings thought to occur secondary to high pressure within the colon, is an extremely common condition in elderly patients. Recent data suggests that up to 50% of people over the age of 60 have colonic diverticula. When a colonic diverticulum becomes inflamed, the result is diverticulitis, a painful condition that can result in colonic obstruction, perforation, or abscess formation. Diverticulitis is a very common cause of acute abdominal pain in elderly individuals, especially in the United States.
Traditionally, diverticulosis and diverticulitis, together falling under the heading of “diverticular disease,” have been considered diseases of the elderly. That stereotype may have to change. A 2009 study by Etzioni et al. used a 1998 to 2005 nationwide inpatient sample to analyze the care given to 267,000 patients admitted with acute diverticulitis. During this eight-year period, admissions for acute diverticulitis increased by 26%. During the same period, admissions in the 18 to 44 year-old age group increased by 82%, far more rapidly than in the older group. For the younger group, the incidence of diverticulitis necessitating inpatient admission increased from 1 in 6600 to 1 in 4000.
Etzioni et al. offer several potential explanations for the rapid rise of diverticulitis cases in young patients. One is that increased use of computed tomography (CT) scanning may have led to a higher rate of detection. This would mean that the actual incidence of diverticulitis has remained stable, but that more cases have been diagnosed. A second possible explanation is that an influx of a specific racial or ethnic group with a high rate of diverticulitis, likely Hispanics, may have increased in number between 1998 and 2005, affecting the results. (It has been suggested that Hispanics are prone to a particularly virulent form of diverticulitis at a young age, but the data are scarce.) The dataset used for the study did not include race or ethnicity, and therefore the authors could not examine racial or ethnic data and could not exclude the possibility of a demographic shift affecting the numbers. The authors rightly note, however, that there is a distinct possibility that from 1998 to 2005 there was a real and dramatic increase in the rate of diverticulitis in younger patients. Why? Diverticulitis has been linked to obesity, poor fiber intake, and the western lifestyle in general, and so its increased incidence is mostly likely related to America’s current obesity epidemic.[3-5]
Two lessons can be gleaned from the data presented in this paper. First is a reminder of that favorite medical axiom, “common things are common.” When a disease is highly prevalent in the overall population, it may be highly prevalent in subsets of the population not stereotypically associated with the disease. Take diverticular disease as an example. According to the Etzioni study, diverticulitis is roughly ten times more common in patients above the age of 75 than in patients aged 18 to 44. It is therefore tempting to dismiss diverticulitis as a potential diagnosis in young patients, because diverticulitis is so much more common in the elderly. This would be a mistake. With a prevalence of 1 in 4000, diverticular disease in young patients is more common than rare causes of abdominal pain classically associated with young people. Symptomatic intestinal malrotation, for example, is classically considered a disease of the young, but is less common than diverticulitis, with a prevalence of 1 in 6000. Decades of high colonic pressure in the elderly increase the chances of diverticula formation, and diverticulitis is certainly less common in the young than it is in the elderly. Still, less common does not equal uncommon.
The second lesson to be learned is that due to increases in obesity and sedentary lifestyle, clinicians should rethink which conditions are diseases of the elderly and which are not. Type II diabetes used to be called adult-onset diabetes until it became so common in children and adolescents that the term became a misnomer. Like type II diabetes, diverticular disease is associated with obesity and sedentary lifestyle, and its increased prevalence can be thought of as a correlate to the increased prevalence of other diseases of the western lifestyle (diabetes, hypertension, coronary artery disease…). If the population of the United States continues to grow more obese and inactive, diverticular disease may become more common.
The patient described in the introduction received a CT scan and was diagnosed with acute diverticulitis. Even after imaging confirmed the diagnosis, the patient’s primary physician was hesitant to accept that diverticulitis was the cause of the patient’s abdominal pain, because she was “too young” to have diverticulitis. The Etzioni paper and other recent studies suggest that this mode of thinking may need to be reexamined. Diverticulitis is a diagnosis that should be considered in all patients with abdominal pain, and not just in the elderly. Remember: common things are common, even in young people.
Dr. Aaron Smith is a former medical student and now a 1st year transitional medicine resident at Harbor-UCLA
Peer reviewed by Michael Poles, MD, Section Editor, Clinical Correlations
Image courtesy of Wikimedia Commons
 Weizman AV, Nguyen GC. Diverticular disease: epidemiology and management. Can. J. Gastroenterol. 2011;25(7):385–389. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3174080/
 Etzioni DA, Mack TM, Beart RW Jr, Kaiser AM. Diverticulitis in the United States: 1998–2005. Annals of Surgery. 2009;249(2):210–217. http://journals.lww.com/annalsofsurgery/pages/articleviewer.aspx?year=2009&issue=02000&article=00006&type=abstract
 Zaidi E, Daly B. CT and clinical features of acute diverticulitis in an urban U.S. population: rising frequency in young, obese adults. AJR Am J Roentgenol. 2006;187(3):689–694. http://www.ajronline.org/doi/abs/10.2214/AJR.05.0033
 Aldoori W, Ryan-Harshman M. Preventing diverticular disease: review of recent evidence on high-fibre diets. Can Fam Physician. 2002;48:1632–1637. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2213940/
 Hjern F, Johansson C, Mellgren A, et al. Diverticular disease and migration–the influence of acculturation to a western lifestyle on diverticular disease. Aliment Pharmacol Ther. 2006;23:797–805. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2036.2006.02805.x/abstract;jsessionid=E566F268C85EEE5067FA4E1664437630.d03t02
 Berseth CL. Disorders of the intestines and pancreas. In: Avery’s Diseases of the Newborn, 7th, Taeusch WH, Ballard RA (Eds), WB Saunders, Philadelphia 1998. 918.
 van de Wall BJ, Poerink JA, Draaisma WA, Reitsma JB, Consten EC, Broeders IA. Diverticulitis in young versus elderly patients: a meta-analysis. Scand J Gastroenterol. 2013. http://informahealthcare.com/doi/abs/10.3109/00365521.2012.758765