This patient's symptoms turned out to be from an uncommon condition—but one that should always be considered in the evaluation of abdominal pain in adults.
George Barbee practices emergency medicine at Womack Army Medical Center, Fort Bragg, North Carolina. He has indicated no relationships to disclose relating to the content of this article.
CASE
A 20-year-old white female presented to the emergency department (ED) with low back pain that radiated to her left anterior/superior hip. The patient stated that she had had hip pain on most days of the week for the past 4 months. The onset of the pain was intermittent, and the patient described it as aching and spasmodic. At its worst, the pain was 10 on a 10-point scale by patient rating. There was no temporal relationship of the symptoms. The pain was somewhat relieved by tramadol (Ultram), 50 mg by mouth 3 times a day, and acetaminophen with hydrocodone, 500 mg/5 mg by mouth every 4 to 6 hours for moderate to severe pain. These medications had been prescribed by the patient's primary care provider.
The patient had undergone an extensive workup for her pain over the past 4 months. This workup included 13 radiologic studies consisting of plain films of the back, hips, and pelvis; a three-phase nuclear medicine study; and MRI of the left hip. The results of all these studies were normal.
The patient also reported an occasional fever at night up to 101°F (38.3°C, oral) and occasional nausea and diarrhea without blood, pus, or mucus. She denied any headache, chills, vomiting, visual changes, neck stiffness, shortness of breath, chest pain, symptoms of urinary tract infection, irregular menses, or gait changes. The patient had never been pregnant, and her last menstrual period was 9 days earlier. She had no history of trauma or lumbar puncture. She had no risk factors for cardiac disease, pulmonary embolism, or deep venous thrombosis. Her immunizations were up-to-date. She had no prior surgeries or significant family history. She did not use tobacco, alcohol, or illicit drugs. She had no history of intravenous drug use. Her last skin tattoo was placed 8 months previously. Her last sexual contact was 6 months previously. She had no history of recent travel, camping, or exposure to insects or animals. She had no drug allergies. Her diet history was not clinically significant.
On physical examination, vital signs were as follows: temperature, 97.4°F (rectal); pulse, 68 beats per minute; respirations, 16 breaths per minute; BP, 110/72 mm Hg; and oxygen saturation, 99% on room air. The patient's general appearance was of a healthy, athletic female; she was in obvious pain, diaphoretic, alert, oriented, and responsive to questions. Her head was normocephalic and atraumatic, and her pupils were 4 mm, equal, and reactive to light. The ears were clear, and tympanic membranes were mobile; the nose was without discharge; and the oropharynx was clear, with moist mucous membranes. The neck was supple, without jugular venous distention, and the trachea was midline. Breath sounds were clear bilaterally. The chest was not tender to palpation, and the breasts were without masses. Heart rhythm was regular and without murmurs, and pulses were equal. The abdomen was soft without distention, and bowel sounds were normoactive. The patient had slight tenderness to palpation in the left lower quadrant near the left anterior superior iliac spine. Otherwise, there were no masses, guarding, or rebound tenderness; obturator and psoas signs were absent. The spine was straight without deviation or crepitus, with tenderness to palpation at the L-4 left paraspinal area. The straight leg raise test was negative to 80 degrees. The pelvic examination revealed normal female genitalia, with a nulliparous, closed cervical os. There was no discharge, cervical motion tenderness, suprapubic tenderness, adnexal tenderness, or masses. The rectal examination showed normal tone, stool in vault, no gross blood, and was negative for occult blood. There was no extremity swelling, edema, limb tenderness, or joint tenderness. The patient had several tattoos on her arms, back, and stomach, but her skin was otherwise clear. Cranial nerves II through XII were intact, muscle stretch reflexes were 2+, and strength was 5/5, with sensation and proprioception intact. The patient's gait was normal.
Laboratory studies revealed the presence of leukocytosis (23,100 WBCs/mm3, with 90% neutrophils). The results of urinalysis and tests for electrolytes, liver function, and kidney function were all normal. Blood cultures, a pregnancy test, a fecal occult blood test, and cultures for sexually transmitted infections were obtained, and all results were negative. A portable anterior/posterior chest radiograph was normal. The previous radiologic studies were also reviewed again and found to be normal.
Meningitis, encephalitis, pneumonia, pulmonary embolism, mesenteric ischemia, large bowel obstruction, pelvic inflammatory disease, ectopic pregnancy, septic arthritis of the hip, hip fracture, lumbar fracture, and spinal neurologic compromise were ruled out based on the chief complaint, patient history, review of systems, and physical examination. The initial differential diagnosis included musculoskeletal back pain, spinal abscess, osteomyelitis via hematogenous spread, left ovarian pathology, or an infectious process.
During the patient's stay in the ED, pain control was achieved with 1 g of acetaminophen (Tylenol) by mouth and IV administration of 5 mg of valium (Diazepam). Abdominal ultrasonography was considered initially, but based on review of the patient's previous studies and presentation, her previous workups, and the differential diagnosis, CT of the abdomen and pelvis with IV and oral contrast was ordered instead. CT was chosen because it would allow evaluation of the abdomen, pelvis, and skeletal structures.
CT revealed a 3-cm small bowel (enteroenteric) intussusception through five slices at the splenic area (see Figure 1 and Figure 2). The surgeon on call was consulted, and the patient was admitted to the surgical service for further workup.
DISCUSSION
Intussusception occurs when a proximal segment of bowel telescopes into the lumen of the adjacent distal segment. Although considered rare in the adult population, approximately 5% to 16% of intussusceptions in the Western world occur in adults.1 Most children present acutely, but adults may have acute, subacute, intermittent, or chronic symptoms.2 In contrast to children, where 80% to 90% of intussusceptions are idiopathic, adult intussusception has a demonstrable cause in more than 90% of cases.3 If left untreated, intussusception can lead to intestinal obstruction.
One retrospective hospital case review spanning 30 years identified 58 adult intussusceptions; the mean patient age was 54.4 years, with a male predominance ratio of 1.8:1, higher enteric versus colonic location (44:1), and slightly higher benign pathology.2 Another hospital case review spanning more than 25 years identified 25 intussusceptions; the mean patient age was 52 years, with a slightly higher male predominance and a slightly higher malignant pathology identified.3
Three types of intussusception can occur, based on location in the bowel: enteroenteric, colocolic, and enterocolic. Enteroenteric intussusception involves only the mesenteric small bowel and is further categorized by the specific small bowel segment involved. Colocolic intussusception involves the colon and is categorized by the specific segment of large bowel involved. Enterocolic intussusception involves both small and large bowel, with two specific subtypes: ileocolic and ileocecal.1
The etiology of most childhood intussusceptions is idiopathic, with recent data implicating lymphotropic viruses as the cause. In the adult patient, there is usually a definable lead point, with neoplasia being the most common etiology.1 Transient, nonobstructing, symptomless intussusception is known to occur in adults, but only a few published cases illustrate the classic features on CT.4 Some causes of this type of intussusception have been associated with known or suspected celiac disease or with Crohn's disease.1
The presenting signs and symptoms of adult intussusception are highly variable. The most commonly described symptom is crampy abdominal pain, noted in 75% to 85% of patients.1 Less frequently reported symptoms are nausea, vomiting, diarrhea, and constipation. Only in a minority of patients are bleeding and a palpable abdominal mass appreciated. One surgical case series of 58 adult patients with intussusception noted some interesting findings.1 In malignant colonic intussusception, patients were more likely to have melena or guaiac-positive stools; patients with benign enteric intussusceptions presented mainly with abdominal pain, nausea, and vomiting.1
Computed tomography remains the most useful and accurate study for detection of intussusception in adults. CT will show the dense composition of the intussuscepted mass comprised of edematous bowel wall and mesentery within the lumen with a characteristic “target” sign or sausage-shaped appearance.5 Although the identification of intussusception can be made confidently on CT, the underlying cause may be difficult to determine. In one study of 16 patients with intussusception, CT was able to correctly identify the causative pathology in only two cases where a lipoma acted as a lead point.5
Ultrasonography can be used to evaluate suspected intussusception in adults and is the second most accurate diagnostic study. The classic features of intussusception on ultrasound include the donut and target signs on the transverse view and the pseudokidney sign on the longitudinal view. In one case series, sonography confirmed the preoperative diagnosis of intussusception in three out of four patients.5 The advantages of sonography are its speed, relative lack of expense, avoidance of radiation and contrast, and the ability to obtain real time data. The limitations of this imaging modality include operator variability, overlying bowel gas, difficulty imaging obese patients, and identification of the underlying cause.1,5
The optimal treatment for adult intussusception remains controversial. For small-bowel intussusception, reduction is attempted initially unless inflammation, bowel ischemia, or malignancy is suspected. In most cases of colonic intussusception, primary resection without reduction should be performed—especially if the patient is older than 60 years, when the incidence of malignancy is high.5
CONCLUSION
This case represents a typical ED visit for a female patient with a history of chronic, vague abdominal and back pain. Based on the patient's history and earlier workups, the PA could easily have reviewed the previous studies, treated the patient symptomatically, and discharged her with good follow-up precautions. What prompted further investigation was the history of intermittent febrile episodes with nausea and diarrhea. The findings of left-sided abdominal pain with leukocytosis and a left shift also were pertinent. The previous studies ruled out an extremity-based musculoskeletal source, as discussed earlier.
This case illustrates the importance of a good clinical decision-making process and the value of reviewing previous studies when these are available. Although intussusception was not in the initial differential diagnosis, the patient's elevated WBC count, nausea, and occasional febrile episodes could not be explained. This led to the review of the patient's previous studies, the choice of CT, and an accurate diagnosis. The cause of the intussusception was never determined in this patient. JAAPA
Acknowledgment: The author would like to thank Dr. Bruce D. Adams, LTC(P), MC, USA, Chief of Emergency Medicine Services, Brooke Army Medical Center, for his guidance with this manuscript.
The opinions or assertions contained herein are the private views of the author and not to be construed as official or as reflecting the views of the US Army Medical Department, Department of the Army, or the Department of Defense. Citation of commercial organizations and trade names in this manuscript do not constitute any official Department of the Army or Department of Defense endorsement or approval of the products or services of these organizations.
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George Barbee practices emergency medicine at Womack Army Medical Center, Fort Bragg, North Carolina. He has indicated no relationships to disclose relating to the content of this article.