Sesame seed products contaminated with Salmonella: three outbreaks associated with tahini

In November 2002, the first of three outbreaks of Salmonella Montevideo infection in Australia and New Zealand was identified in New South Wales, Australia. Affected persons were interviewed, and epidemiologically linked retail outlets inspected. Imported tahini was rapidly identified as the source of infection. The contaminated tahini was recalled and international alerts posted. A second outbreak was identified in Australia in June-July 2003 and another in New Zealand in August 2003. In a total of 68 S. Montevideo infections, 66 cases were contacted. Fifty-four (82%) reported consumption of sesame seed-based foods. Laboratory analyses demonstrated closely related PFGE patterns in the S. Montevideo isolates from human cases and sesame-based foods imported from two countries. On the basis of our investigations sesame-based products were sampled in other jurisdictions and three products in Canada and one in the United Kingdom were positive for Salmonella spp., demonstrating the value of international alerts when food products have a wide distribution and a long shelf life. A review of the controls for Salmonella spp. during the production of sesame-based products is recommended.

Outbreaks of enterotoxigenic Escherichia coli infection in American adults: a clinical and epidemiologic profile

Because enterotoxigenic Escherichia coli (ETEC) is not identified by routine stool culture methods, ETEC outbreaks may go unrecognized, and opportunities for treatment and prevention may be missed. To improve recognition of adult ETEC outbreaks, we compared them with reported outbreaks of viral gastroenteritis. During 1975-95, we identified 14 ETEC outbreaks in the United States and 7 on cruise ships, caused by 17 different serotypes and affecting 5683 persons. Median symptom prevalences were: diarrhoea 99%, abdominal cramps 82%, nausea 49%, fever 22%, vomiting 14%. The median incubation period was 42 h, and for 8 of 10 outbreaks, the mean or median duration of illness was > 72 h (range 24-264). For 17 (81%) ETEC outbreaks, but for only 2 (8%) viral outbreaks, the prevalence of diarrhoea was > or = 2.5 times the prevalence of vomiting. ETEC outbreaks may be differentiated from viral gastroenteritis outbreaks by a diarrhoea-to-vomiting prevalence ratio of > or = 2.5 and a longer duration of illness.

A retrospective search for lyssavirus in humans in the Northern Territory

BACKGROUND

Following the 1996 discovery of a rabies-like lyssavirus in Australian flying foxes, it was unclear whether this was a new epizootic or an unrecognised, previously existing disease.

OBJECTIVE

To review cases of unexplained encephalitis in the Northern Territory (NT) to test available clinical specimens for lyssavirus and survey the use of diagnostic tests by clinicians.

METHODS

The NT hospital morbidity database was searched from January 1992 to September 1996 for all Royal Darwin Hospital (RDH) cases with an ICD-9 code encompassing encephalitis or viral meningitis. Final diagnoses were determined by hospital record review. For cases of unexplained encephalitis, we assessed the use of diagnostic tests and located clinical specimens for testing for lyssavirus-specific inclusion bodies via immunohistochemistry, immunofluorescence and reverse-transcriptase polymerase chain reaction (RT-PCR).

RESULTS

Encephalitis occurred in 34/154 (22%) cases located by the search; 53% (18/34) of encephalitis cases were unexplained. Of these, 24% had no serology performed and 47% had no blood cultures taken. Four (22%) died and two had autopsies. These were the only two cases with clinical specimens available for testing. They were negative for lyssavirus. None of the 71 cases coded as viral meningitis had unexplained encephalitis.

CONCLUSION

There was a considerable proportion of unexplained illness among NT cases of encephalitis.

IMPLICATIONS

Clinicians should test for lyssavirus in patients with encephalitic symptoms and a postmortem should be sought where death is unexplained. Specimens should be stored to enable testing for emerging infectious diseases.

Timeliness of Salmonella notifications in South Australia

OBJECTIVE

To evaluate the timeliness of Salmonella serotype and phage type notifications in South Australia.

METHOD

We surveyed all notifications of Salmonella to the South Australian Department of Human Services between July 1995 and June 1996. We entered data onto an Epi Info 6.02 database and calculated the time interval between various stages of typing notification.

RESULTS

The median time taken between collection of a faecal specimen and receipt of serotype notification was 10 days (range, 5-38), while phage type notification took a further seven days (range 0-40). The time interval between collection of a specimen and notification of a Salmonella final identity was 14 days (range 6-49). The internal mail system of the Department of Human Services delayed notification a median of two days. Environmental Health Officers supplied reports for 224 (58%) of 384 cases, 71% of which occurred before the final Salmonella isolate was known.

CONCLUSIONS

We found that the internal departmental mail system delayed the notification of Salmonella. In South Australia, investigations should focus on clusters of cases of known Salmonella identity, rather than all notified cases.

IMPLICATIONS

To improve communicable disease investigations, health agencies should evaluate the timeliness of surveillance systems and examine the feasibility of transferring laboratory data electronically.

Diagnosis and treatment of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common medical disorder characterized by symptoms of abdominal pain and bowel dysfunction. It is associated with significant disability and health care costs. A practical approach to diagnosis is the symptom-based Rome criteria. Management of patients has been helped by recent findings relating to the epidemiology, pathophysiology and psychosocial contributions of the disorder. Dysregulation of intestinal motor, sensory and central nervous system function is currently believed to be the basis for IBS symptoms. Symptoms are due to both abnormal intestinal motility and enhanced visceral sensitivity. Psychosocial factors are not a cause but can affect the illness experience and clinical outcome. Finally, treatment involves an effective physician-patient relationship and an integrated pharmacologic and behavioral approach that is determined by the needs of the patient, the type and severity of the symptoms and the degree of disability.

A cost-effectiveness analysis of directly observed therapy vs self-administered therapy for treatment of tuberculosis

STUDY OBJECTIVES

To compare the costs and effectiveness of directly observed therapy (DOT) vs self-administered therapy (SAT) for the treatment of active tuberculosis.

DESIGN

Decision analysis.

SETTING

We used published rates for failure of therapy, relapse, and acquired multidrug resistance during the initial treatment of drug-susceptible tuberculosis cases using DOT or SAT. We estimated costs of tuberculosis treatment at an urban tuberculosis control program, a municipal hospital, and a hospital specializing in treating drug-resistant tuberculosis.

OUTCOME MEASURES

The average cost per patient to cure drug-susceptible tuberculosis, including the cost of treating failures of initial treatment.

RESULTS

The direct costs of initial therapy with DOT and SAT were similar ($1,206 vs $1,221 per patient, respectively), although DOT was more expensive when patient time costs were included. When the costs of relapse and failure were included in the model, DOT was less expensive than SAT, whether considering outpatient costs only ($1,405 vs $2,314 per patient treated), outpatient plus inpatient costs ($2,785 vs $10,529 per patient treated), or outpatient, inpatient, and patients' time costs ($3,999 vs $12,167 per patient treated). Threshold analysis demonstrated that DOT was less expensive than SAT through a wide range of cost estimates and clinical event rates.

CONCLUSION

Despite its greater initial cost, DOT is a more cost-effective strategy than SAT because it achieves a higher cure rate after initial therapy, and thereby decreases treatment costs associated with failure of therapy and acquired drug resistance. This cost-effectiveness analysis supports the widespread implementation of DOT.

Diagnosis and treatment of irritable bowel syndrome

Irritable bowel syndrome is a common disorder characterized by symptoms of abdominal pain with diarrhea and/or constipation. It is associated with significant disability and health care costs. A practical approach to diagnosis utilizes the symptom-based Rome criteria. Management of patients has been helped by recent findings relating to the pathophysiology of the disorder. Dysregulation of intestinal motor functions, sensory functions and central nervous system functions is currently believed to be the basis for irritable bowel symptoms. Symptoms are a result of both abnormal intestinal motility and enhanced visceral sensitivity. Psychosocial factors can affect the illness experience and the clinical outcome. An effective physician-patient relationship is required for a successful outcome. Individualized treatment involves an integrated pharmacologic and behavioral approach determined by the predominant symptom type, the severity of the symptoms and the degree of disability.

An outbreak of gastroenteritis and fever due to Listeria monocytogenes in milk

BACKGROUND

After an outbreak of gastroenteritis and fever among persons who attended a picnic in Illinois, chocolate milk served at the picnic was found to be contaminated with Listeria monocytogenes.

METHODS

In investigating this outbreak, we interviewed the people who attended the picnic about what they ate and their symptoms. Surveillance for invasive listeriosis was initiated in the states that receive milk from the implicated dairy. Stool and milk samples were cultured for L. monocytogenes. Serum samples were tested for IgG antibody to listeriolysin O.

RESULTS

Forty-five persons had symptoms that met the case definition for illness due to L. monocytogenes, and cultures of stool from 11 persons yielded the organism. Illness in the week after the picnic was associated with the consumption of chocolate milk. The most common symptoms were diarrhea (present in 79 percent of the cases) and fever (72 percent). Four persons were hospitalized. The median incubation period for infection was 20 hours (range, 9 to 32), and persons who became ill had elevated levels of antibody to listeriolysin O. Isolates from stool specimens from patients who became ill after the picnic, from sterile sites in three additional patients identified by surveillance, from the implicated chocolate milk, and from a tank drain at the dairy were all serotype 1/2b and were indistinguishable on multilocus enzyme electrophoresis, ribotyping, and DNA macrorestriction analysis.

CONCLUSIONS

L. monocytogenes is a cause of gastroenteritis with fever, and sporadic cases of invasive listeriosis may be due to unrecognized outbreaks caused by contaminated food.

Blood lead levels in radiator repair workers in Colorado

A laboratory-based blood lead surveillance system in Colorado identified radiator repair workers as having the highest blood lead levels of all worker groups reported. A survey of 42 radiator repair shops in ten locales throughout Colorado was undertaken to estimate the prevalence of workers with elevated blood lead levels > 25 micrograms/dL. The survey was designed to test the sensitivity of the surveillance system and to assess working conditions and practices in the radiator repair industry in Colorado. Of 63 workers, 39 (62%) had blood lead levels > 25 micrograms/dL. The sensitivity of the surveillance system for detecting radiator repair workers with elevated blood lead levels was estimated at 11%. None of the radiator repair shops had adequate local exhaust ventilation. Work practice and engineering modifications are needed to reduce lead exposure in this industry.

Foodborne disease: current trends and future surveillance needs in Australia

Review of 128 outbreaks of foodborne disease (affecting almost 6000 people, with six deaths) between 1980 and 1995 and available surveillance data showed that foodborne disease in Australia is similar to that in other industrialised countries. Campylobacter spp. and non-typhoidal Salmonella spp. were the most commonly reported pathogens. However, Australia, unlike the UK and US, lacks a comprehensive national surveillance system for foodborne diseases. This is essential to improve control of these diseases.

The cost of a food-borne outbreak of hepatitis A in Denver, Colo

BACKGROUND

In 1992, a food-borne outbreak of hepatitis A associated with a catering facility in Denver, Colo, resulted in 43 secondary cases of hepatitis A and the potential exposure of approximately 5000 patrons.

OBJECTIVES

To assess (1) disease control costs, including state and local health department personnel costs, provision and administration of immune globulin, and cost of extra hepatitis A serologic tests performed; (2) business losses; and (3) cost of the cases' illnesses.

METHODS

Cost data were collected from hospitals, health maintenance organizations, health departments, laboratories, the caterer's insurance company, and the catering facility involved in the outbreak.

RESULTS

The total costs assessed in the outbreak from a societal perspective were $809,706. Disease control costs were $689,314, which included $450,397 for 16,293 immune globulin injections and $105,699 for 2777 hours of health department personnel time. The cases' medical costs were $46,064, or 7% of the disease control costs.

CONCLUSIONS

The cases' medical costs and productivity losses were only a minor component of the total cost of this outbreak. The high cost of food-borne outbreaks should be taken into account in economic analyses of the vaccination of food handlers with inactivated hepatitis A vaccine.

Effect of different coffees on esophageal acid contact time and symptoms in coffee-sensitive subjects

The purpose of this study was to correlate the effects of different coffees on esophageal acid contact, heartburn, and regurgitation in patients with coffee-sensitivity. Twenty volunteers with coffee-sensitivity were studied in a double-blind, 3 period, crossover study examining the effect of three regular (caffeinated) coffees (a coffee from the USA--"A"; a "treated" coffee from Europe--"B"; and an "untreated" coffee from Europe--"C") before and after a high-fat test meal. The median acid contact times for coffees A, B, and C were 6.5%, 9%, and 10.5%, respectively (A vs. C, p = 0.005). Significantly fewer patients reported any symptoms with coffee A compared with coffee C (p < 0.05). Symptoms were usually more frequent and severe after the test meal. There was a trend toward fewer and less severe symptoms with the treated coffee (B) compared with its untreated counterpart (C). Our conclusions are as follows: (a) Different coffees induce variations in gastroesophageal reflux in coffee-sensitive individuals. (b) Coffee can be treated in a manner which decreases heartburn symptoms by 75% while decreasing acid contact by only 14%. (c) Gastroesophageal reflux and symptoms of coffee sensitivity increase with the concomitant ingestion of food. (d) Symptoms of dyspepsia appear to be influenced by variations in both the coffee itself and characteristics of susceptible individuals. (e) Although gastroesophageal reflux is important in the genesis of coffee-sensitivity, there must be other factors which act in concert with reflux to produce symptoms of coffee-sensitivity.

The effect of propofol on the canine sphincter of Oddi

To assess the effect of propofol on the canine sphincter of Oddi(SO), sphincter of Oddi manometry (SOM) was performed in fasting dogs which had undergone cholecystectomy and placement of modified Thomas duodenal cannulae. Using two water-perfused, single-lumen manometric catheters, SO and duodenal pressures were measured simultaneously. Baseline SO activity was recorded for at least one complete interdigestive cycle followed by bolus injections of propofol (Diprivan) (N = 31) from 0.1 to 4.0 mg/kg during Phase I of the Migrating Motor Complex (MMC). When propofol was administered in bolus doses < or = 0.4 mg/kg, no change in SO or duodenal motor function was seen. In doses > or = 0.5 mg/kg, SO basal pressure, amplitude, and frequency of contractions increased significantly. Increases in duodenal activity paralleled SO activity. Our results suggest that propofol in low doses may be useful for sedation during Sphincter of Oddi manometry in humans. Further studies of the effect of propofol on the human sphincter of Oddi are warranted.

The relationship between stress and symptoms of gastroesophageal reflux: the influence of psychological factors

This paper describes the first controlled study of the relationships among stress, psychological traits associated with chronic anxiety, acid reflux parameters, and perceptions of reflux symptoms. Seventeen subjects with symptomatic reflux disease were studied using a 2 (high vs. low gastrointestinal susceptibility score) x 2 (stress vs. neutral tasks) x 3 (periods 1, 2, or 3) experimental design. It was found that the stress tasks produced significant increases in systolic and diastolic blood pressure, pulse rates, and subjective ratings of anxiety and reflux symptoms. The stress tasks, however, did not influence objective parameters of acid reflux (total acid exposure, number of reflux episodes, duration of longest reflux episode). Moreover, the effect of stress on reflux ratings was due primarily to the responses of the subjects with high gastrointestinal susceptibility scale scores. These subjects' reflux ratings remained at high levels during all stress periods, whereas subjects in all other experimental conditions reported decreased reflux symptoms across periods. These results suggest that reflux patients who are chronically anxious and exposed to prolonged stress may perceive low intensity esophageal stimuli as painful reflux symptoms. Future effort should be devoted to examining the efficacy of anxiolytic and behavioral therapies with these reflux patients.

Effects of nifedipine on esophageal tone and perception of esophageal distension

The effects of nifedipine (20 mg orally) on esophageal body resting tone and perception of esophageal distension were compared with those of placebo in 10 healthy volunteers, using a double-blind crossover design. A 3-cm silicon balloon positioned 10 cm above the lower esophageal sphincter was inflated with 2-20 ml of air, in 2-ml increments. The subjects scored their chest sensations, while pressure in the balloon was continuously recorded. In each experiment three series of measurements were made, at baseline and 15 and 30 min after administration of nifedipine or placebo. Bench tests were run to determine pressure-to-volume relationships for each of the balloons used in the study. Thirty minutes after nifedipine ingestion, a significant decrease in systolic blood pressure (from 112.6 +/- 2.3 to 99.0 +/- 2.0 mm Hg) was observed. Amplitude and duration of esophageal peristaltic contractions were significantly decreased by nifedipine (from 128.1 +/- 16.7 to 98.7 +/- 10.6 mm Hg and from 3.9 +/- 0.3 to 3.3 +/- 0.2 sec, respectively). With balloon volumes of 8 ml and higher, balloon pressures were higher with the balloon in the esophagus than on the bench, the difference being determined by the compliance of the esophagus. This difference rose from 18.5 +/- 6.8 to 40.2 +/- 7.2 mm Hg (8-20 ml) with placebo and from 23.1 +/- 3.7 to 35.9 +/- 5.8 mm Hg with nifedipine. No significant differences between nifedipine and placebo were found. The esophageal sensation scores increased linearly with increasing balloon volume from 6 ml onwards. Nifedipine had no significant effect on the perception of esophageal balloon distension.

Alginic acid decreases postprandial upright gastroesophageal reflux. Comparison with equal-strength antacid

This study tested the hypothesis that (alginic) acid may have a preferential effect on reflux in the upright position. We evaluated the effect of a compound containing alginic acid plus antacid (extra-strength Gaviscon) versus active control antacid with equal acid-neutralizing capacity on intraesophageal acid exposure following a high-fat meal (61% fat: sausage, egg, and biscuit). In random sequence, each of the 10 volunteers received either alginic acid-antacid or control antacid immediately following and 1, 2, and 3 hr after the meal. The sequence was repeated for both test drugs in the supine and upright positions with constant pH monitoring. Alginic acid-antacid significantly decreased postprandial reflux in the upright position compared to an equal amount of antacid. This effect did not occur in the supine position. These findings support the hypothesis that alginic acid is primarily effective in the upright position and the clinical observations of the effectiveness of alginic acid on daytime reflux symptoms.

Cerebral potentials evoked by oesophageal distension in patients with non-cardiac chest pain

Cerebral evoked potential recording was used to study the oesophagus-brain axis in 10 controls and 10 patients with non-cardiac chest pain with a manometric diagnosis of either nutcracker oesophagus or diffuse spasm and a positive edrophonium test. A series of 50 inflations (10/minute; inflation rate of 170 ml/second) of an intraoesophageal balloon (5 cm proximal to the lower oesophageal sphincter) was performed in each subject. Three different inflation volumes were used and were individually determined to cause no sensation, slight sensation, and definite sensation, respectively (volume ranges: 2-8 ml, 5-18 ml, and 8-22 ml). All signals were coded and their quality was scored on a scale from 0 (no recognisable pattern) to 5 (well defined potential of good quality) by four 'blinded' observers. The evoked potential quality scores and amplitude of the major peaks increased significantly (p less than 0.01) with increasing sensation, both in patients and in controls. In the patients, quality score and amplitude of all four peaks of the evoked potentials were lower (p less than 0.05) and latencies of two of the four peaks were longer (p less than 0.02) than in the controls. The volumes of air required to produce the various sensations were lower in the patients (p less than 0.01). When divided by the balloon volume, amplitude and quality of the evoked potential were no longer significantly different between the groups. These results suggest that the increased perception of oesophageal distension in patients with non-cardiac chest pain is caused by altered central processing rather than (functionally) abnormal receptors in the oesophageal wall.

Musculoskeletal chest wall syndromes in patients with noncardiac chest pain: a study of 100 patients

One hundred patients with chest pain and negative coronary arteriography were evaluated for musculoskeletal chest wall findings. Sixty-nine patients had chest wall tenderness. Typical chest pain was evoked by palpation in 16 patients. Tender areas were not found in a control group of patients without chest pain. A diagnosis of fibrositis could be made in five patients, including two in whom chest palpation reproduced typical chest pain. The sternal and xiphoid area, left costosternal junctions, and left anterior chest wall were the areas where tenderness was most common, but no significant differences were found comparing locations of tenderness in those with reproduction of typical pain. There was no significant difference in location, exacerbating factors, or other musculoskeletal symptoms among different groups of patients. Thus, most patients with noncardiac chest pain have chest wall tenderness that is not found in a control group without chest pain. However, reproduction of pain by palpation, a more specific diagnostic finding, is found in a minority of these patients.

Diffuse esophageal spasm. A rare motility disorder not characterized by high-amplitude contractions

Diffuse esophageal spasm (DES) has frequently been described as a motility disorder characterized by simultaneous, high-amplitude contractions. We reviewed the results of esophageal manometry testing on a total of 1480 patients referred to our lab over 36 months. Lower esophageal sphincter (LES) pressure was determined by a mean of four station pull-through. Esophageal body motility was assessed following 10 wet swallows. In our lab a diagnosis of DES is made when greater than 10% but less than 100% of contractions are simultaneous. Manometric findings of DES were rare, with an overall prevalence of 4% (56/1480). Of the 56 patients with a manometric diagnosis of DES, high-amplitude (mean greater than or equal to 180 mm Hg) peristaltic contractions were found in only two (4%). No simultaneous contractions with amplitude greater than or equal to 180 mm Hg were seen. Pressures of simultaneous contractions were consistently lower than peristaltic contractions. A hypertensive LES pressure (greater than or equal to 45 mm Hg) was present in 5/56 DES patients (9%). Poor LES relaxation was found in 7/56 DES patients (13%). We conclude that DES is a rare manometric finding, regardless of the reason for referral, and that the occurrence of high-amplitude contractions in DES is equally rare.

Twenty-four-hour esophageal pH monitoring: the most useful test for evaluating noncardiac chest pain

STUDY OBJECTIVE

To compare the diagnostic capabilities of traditional esophageal tests (manometry and provocative testing with acid and edrophonium) and 24-hour esophageal pH monitoring in identifying an esophageal cause of chest pain.

DESIGN

A prospective study of 100 consecutive patients referred by cardiologists to the esophageal laboratory for evaluation of esophageal causes of chest pain.

SETTING

Tertiary-referral university hospital.

METHODS

Esophageal manometry performed with 10 wet swallows of water. Acid perfusion (0.1 N hydrochloric acid) and edrophonium (80 micrograms/kg intravenously) tests were placebo-controlled with a positive study defined as replication of typical chest pain. Esophageal pH monitoring identified (1) abnormal acid exposure times in the upright, supine, or combined position, and (2) correlation between symptoms and acid reflux, i.e., symptom index. The esophagus was identified as "probably" contributing to chest pain only if the acid or edrophonium test was positive or if there was a positive correlation between symptoms and acid reflux during pH monitoring.

RESULTS

Esophageal manometry was abnormal in 32 patients (32%), but patients were asymptomatic during the study. The acid perfusion test was positive in 18 of 95 patients (19%), and the edrophonium test was positive in 15 of 78 patients (19%). Abnormal acid exposure times were found in 48 patients (48%). Of the 83 patients with spontaneous chest pain during 24-hour pH testing, 37 patients (46%) had abnormal reflux parameters and 50 patients (60%) had a positive symptom index (mean positive score 56%, range 6% to 100%).

CONCLUSIONS

Acid reflux is a common and potentially treatable cause of noncardiac chest pain. Traditional esophageal tests usually miss this diagnosis. Twenty-four-hour esophageal pH monitoring with symptom correlation is the single best test for evaluating patients with noncardiac chest pain.

Twenty-four-hour esophageal pH monitoring: the most useful test for evaluating noncardiac chest pain

STUDY OBJECTIVE

To compare the diagnostic capabilities of traditional esophageal tests (manometry and provocative testing with acid and edrophonium) and 24-hour esophageal pH monitoring in identifying an esophageal cause of chest pain.

DESIGN

A prospective study of 100 consecutive patients referred by cardiologists to the esophageal laboratory for evaluation of esophageal causes of chest pain.

SETTING

Tertiary-referral university hospital.

METHODS

Esophageal manometry performed with 10 wet swallows of water. Acid perfusion (0.1 N hydrochloric acid) and edrophonium (80 micrograms/kg intravenously) tests were placebo-controlled with a positive study defined as replication of typical chest pain. Esophageal pH monitoring identified (1) abnormal acid exposure times in the upright, supine, or combined position, and (2) correlation between symptoms and acid reflux, i.e., symptom index. The esophagus was identified as "probably" contributing to chest pain only if the acid or edrophonium test was positive or if there was a positive correlation between symptoms and acid reflux during pH monitoring.

RESULTS

Esophageal manometry was abnormal in 32 patients (32%), but patients were asymptomatic during the study. The acid perfusion test was positive in 18 of 95 patients (19%), and the edrophonium test was positive in 15 of 78 patients (19%). Abnormal acid exposure times were found in 48 patients (48%). Of the 83 patients with spontaneous chest pain during 24-hour pH testing, 37 patients (46%) had abnormal reflux parameters and 50 patients (60%) had a positive symptom index (mean positive score 56%, range 6% to 100%).

CONCLUSIONS

Acid reflux is a common and potentially treatable cause of noncardiac chest pain. Traditional esophageal tests usually miss this diagnosis. Twenty-four-hour esophageal pH monitoring with symptom correlation is the single best test for evaluating patients with noncardiac chest pain.

Acid perfusion test and 24-hour esophageal pH monitoring with symptom index. Comparison of tests for esophageal acid sensitivity

The acid perfusion (Bernstein) test and esophageal pH monitoring are the two most popular tests for identifying esophageal acid sensitivity in difficult cases of reflux disease. Therefore, we prospectively compared these test results in 75 consecutive noncardiac chest pain patients who had both an acid perfusion test and chest pain during 24-hr pH testing. A positive acid perfusion test was defined by the replication of the patient's typical chest pain twice by the acid infusion. Esophageal pH testing identified abnormal amounts of acid reflux and correlated symptoms with acid reflux--the "symptom index." Fifteen patients (20%) had a positive acid perfusion test while 45 patients (59%) had a positive symptom index (range 6-100%). Only 9/34 (26%) patients with abnormal reflux had a positive acid perfusion test. Although it had excellent specificity (83-94%), the acid perfusion test had poor sensitivity (32-46%) when compared to the symptom index regardless of the percent positive cutoff level. The best positive predictive value for the acid perfusion test was 87%, but this occurred when the test sensitivity was 32%. Modifying the end point of a positive acid perfusion test to include heartburn improves the sensitivity (52-67%) while markedly compromising specificity and positive predictive value. Thus, esophageal pH monitoring correlating symptoms with acid reflux is superior to the acid perfusion test for identifying an acid sensitive esophagus in patients with noncardiac chest pain.

Edrophonium provocative test in noncardiac chest pain. Evaluation of testing techniques

Edrophonium chloride is used frequently as a provocative agent in the assessment of noncardiac chest pain (NCCP). However, the optimum dose and most appropriate method of interpreting test results is controversial. We studied 150 consecutive NCCP patients and 50 age-matched controls who alternately received either 80 micrograms/kg or 10 mg intravenous bolus doses of edrophonium preceded by saline placebo injections. Distal esophageal pressures were measured before and after drug injection in response to ten 5-cc wet swallows. Following 10 mg of edrophonium, 33% of patients and 4% of controls reported chest pain, while 29% of patients and no controls receiving the 80 micrograms/kg dose complained of chest pain. Amplitude changes after either dose were not significantly different for all comparisons, but the duration of response did distinguish the two doses in patients with chest pain. A significantly greater (P = 0.01) increase in distal contraction duration occurred after 10 mg (74 +/- 12%; +/- SE) compared to 80 micrograms/kg dose (43 +/- 6%). However, individual responses to the two doses overlapped considerably. If a positive test is redefined to include both chest pain and manometric changes that are significantly different from controls, the positivity rate changes drastically; 33% to 9% in the 10-mg group and 30% to 3% in the 80-micrograms/kg group. Side effects were similar between doses, but there was a significant (P = 0.02) linear relationship between intensity of side effects and the edrophonium dose per kilogram of body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of body position and bolus consistency on the manometric parameters and coordination of the upper esophageal sphincter and pharynx

The development of a solid-state intraluminal sphincter transducer has alleviated many of the problems associated with manometric studies of the upper esophageal sphincter (UES) and pharynx (P). We used this technology to study the effect of position (upright vs. supine) on resting UES pressures and the pressure dynamics of the UES/P complex during both wet and dry swallows in 11 normal volunteers and the effects of foods of different consistencies on the UES/P swallow dynamics in 10 normal volunteers. The UES/P coordination parameters were defined as the 15 time intervals that can be measured between any 2 of 6 pertinent points: the beginning, peak, and end of the pharyngeal contraction and the beginning, nadir, and end of the UES relaxation. Data from both the circumferential transducer used to measure sphincter pressures and a standard microtransducer used to measure pharyngeal pressures were collected on-line by an Apple IIe microcomputer and analyzed by programs written in our laboratory. Significant changes in swallow coordination were measured between upright and supine swallows of the same bolus size, between wet and dry swallows in the same position, and among foods of varying consistencies. Resting UES pressure was unchanged by position and pharyngeal contraction pressure was unchanged by bolus size or consistency.

Aging-related alterations in human upper esophageal sphincter function

Recent improvements in manometric catheters have made measurement of pharyngeal (P) and upper esophageal sphincter (UES) swallowing mechanics more reliable. Few studies have attempted to evaluate the effect of normal aging on P and UES mechanics. Pharyngeal and upper esophageal sphincter dynamics were studied in 10 healthy elderly adults (age greater than 60; range 62-79 yr) and 10 younger adults (age less than 60; range 24-59 yr). A solid-state intraluminal transducer system was used with a proximal unidirectional Konigsberg microtransducer and a circumferential (sphincter) transducer located 5 cm distally. Mean resting UES pressure was significantly (p less than 0.05) lower in the elderly than in the younger subjects (52 +/- 5 vs 72 +/- 6 (SE)) mm Hg. A significant inverse relation (R = -0.54; p less than 0.02) was found between age and resting UES pressure. Time from peak of pharyngeal contraction to UES nadir was significantly (p less than 0.05) shortened in the healthy elderly vs younger controls (10 +/- 30 vs 90 +/- 20 ms) during dry swallows. Our studies indicate that aging is associated with lower resting UES pressure and delayed UES relaxation, relative to the pharyngeal peak.

Pharyngeal/upper esophageal sphincter pressure dynamics in humans. Effects of pharmacologic agents and thermal stimulation

Extensive physiological studies of swallowing have been carried out in laboratory animals; however, similar studies in humans have been limited by available technology. In this study we describe the use of a solid-state circumferential sphincter transducer to define manometric characteristics of the human pharynx and upper esophageal sphincter (UES). Effects of pharmacologic agents and thermal stimulation are also described. We studied nine normal volunteers on three separate days. All studies were done in the upright position and consisted of a station pull-through of the UES and six wet swallows with the sphincter transducer in the most proximal segment of the UES and a posteriorly oriented single transducer 5 cm proximal in the pharynx. Baseline studies preceded all drug studies. Effects of bethanechol were studied on day 1, cold stimulation and benzonatate on day 2, edrophonium and atropine on day 3. The UES resting pressure showed large intrasubject day-to-day variations; however, mean values did not differ. There were no effects on UES relaxation or swallow coordination with any of the pharmacologic agents, although benzonatate produced multiple pharyngeal contractions.

The prevalence of abnormal esophageal test results in patients with cardiovascular disease and unexplained chest pain

The purpose of our study was to assess the prevalence of esophageal test abnormalities in patients with known cardiovascular disease and persistent chest pain. We performed a retrospective review of symptoms, manometry, and provocative test results performed on patients with undiagnosed chest pain. The 220 patients with angiographically determined cardiac disease and persistent chest pain were divided into three groups: coronary artery disease (125 patients), mitral valve prolapse (38 patients), and coronary bypass/angioplasty (57 patients). A comparison group consisted of 159 patients with noncardiac chest pain. All patients underwent esophageal manometry and placebo-controlled provocative testing (acid perfusion test and edrophonium chloride test). The prevalence of esophageal motility disorders in the noncardiac chest pain group (27%) was similar to that in the coronary artery disease (24%), mitral valve prolapse (37%), and coronary bypass/angioplasty (30%) groups. The frequency of nutcracker esophagus (11% to 16%) and diffuse esophageal spasm (2% to 7%) was remarkably constant. The prevalence of any positive provocative result in the noncardiac chest pain group (27%) was similar to that in the coronary artery disease (19%), mitral valve prolapse (32%), and coronary bypass/angioplasty (20%) groups. Furthermore, completely negative results of esophageal investigation occurred in 55%, 62%, 42%, and 59% of the respective patient groups.

Comparison of esophageal manometry, provocative testing, and ambulatory monitoring in patients with unexplained chest pain

Prolonged ambulatory esophageal pH and pressure monitors are being developed to evaluate noncardiac chest pain. This new technology needs comparison with conventional esophageal tests before determining which studies are most useful in diagnosing and treating esophageal chest pain. Therefore, we studied 45 patients with esophageal manometry, acid perfusion and edrophonium tests, and 24 hr pH and pressure monitoring. Manometry was abnormal in 20 patients (44%) with nutcracker esophagus, the most common motility disorder. Fifteen (33%) had positive acid perfusion test and 24 (55%) positive edrophonium test. During ambulatory monitoring, all patients experienced chest pain with a total of 202 individual events: 32 events (15%) secondary to acid reflux, 15 (7%) secondary to motility abnormalities, 7 (3%) to both pH and pressure changes, and 149 events (74%) occurred in the absence of any abnormal pH or motility changes. Patients with normal manometry were significantly (P less than 0.01) more likely to have acid reflux chest pain events than did nutcracker patients, who had an equal frequency of pH and motility events. A positive acid perfusion test was significantly associated with abnormal pressure events (P = 0.02; odds ratio 5.95), while a positive edrophonium test more likely predicted acid reflux chest pain during 24-hr monitoring (P = 0.007; odds ratio 7.25). Therefore, abnormal manometry and positive provocative tests point to the esophagus as the likely source of chest pain. However, ambulatory pH and pressure monitoring are required to accurately define the relationship between chest pain and acid reflux or motility disorders.(ABSTRACT TRUNCATED AT 250 WORDS)

Manometry and radiology. Complementary studies in the assessment of esophageal motility disorders

The relationship between radiological and manometric findings in esophageal motility disorders is poorly understood. Therefore, 20 subjects (4 normal; 13 diffuse spasm; 3 other motility disorders) were studied using synchronous manometry and videofluoroscopy with alternate 5-ml and 10-ml barium swallows. A total of 181 swallows were analyzed. Concordance between manometry and fluoroscopy was excellent for individual swallows (98%), groups of 5 swallows (97%), and final diagnoses (90%). Contraction onset intervals less than 0.8 s apart over 5 cm (velocity greater than 6.25 cm/s) were critical in determining abnormal bolus transit (98% sensitivity and positive predictive value). Radiologically, segmental tertiary activity (complete luminal obliteration) was always associated with disrupted primary peristalsis, but nonsegmental tertiary activity was often seen with normal bolus transit and did not have a specific manometric correlate. Four patterns of interrupted peristalsis radiologically were found--segmental tertiary contractions, a generalized esophageal contraction, absence of motor activity, or discoordinated "to-and-fro" movement. Surprisingly, nearly complete barium clearance occurred by the first two mechanisms in two thirds of swallows. Thus, the authors believe radiology and manometry are both excellent studies for identifying abnormal esophageal peristalsis. In difficult cases, these tests give complementary information because radiology assesses bolus movement while manometry provides quantitative pressure data.

Pharyngeal and upper esophageal sphincter manometry in humans

Manometric studies of pharyngeal-upper esophageal sphincter (UES) coordination during swallowing have proven difficult. Asymmetry of the UES makes pressure measurements with a single, unoriented transducer suspect. Perfused systems lack the necessary response rate for measuring peak pharyngeal contraction pressures. Precise quantification of the coordination of pharyngeal contractions and UES relaxations during swallowing is difficult because of rapid pressure changes. We tested a modified solid-state transducer that measures pressures over 360 degrees. This transducer was placed in the proximal UES with a second, single transducer 5 cm proximal. Data were collected and analyzed with an Apple IIe microcomputer. A computer program was developed to measure nine timing sequences, UES resting pressure, nadir of UES relaxation, and pharyngeal contraction pressures. We studied 21 volunteers with six swallows each for dry, 5, 10, and 20 ml of water. Dry swallows differed significantly (P less than 0.05) from wet (5 ml). All timing sequences became progressively longer with increasing bolus size. Residual pressures were unchanged. Timing sequences were also measured for wet (5 ml) and dry swallows in seven volunteers using a Dent sleeve and single perfused orifice in the UES; no differences were seen.

Esophageal motility: assessment with synchronous video tape fluoroscopy and manometry

Synchronous video tape fluoroscopy and manometry of the esophagus was performed in 11 subjects (seven men and four women; mean age, 49 years). Four had normal and seven had abnormal esophageal motility (diffuse esophageal spasm, n = 4; nonspecific esophageal motility disorder, n = 3) that was shown by previous manometry. A digital timer appeared on the video tape recording and marked the manometric tracing synchronously. Alternate 5-mL and 10-mL barium boluses were recorded for a total of 10 swallows per patient. Video tape examinations were reviewed prospectively, and the status of primary peristalsis and presence and severity of tertiary activity were noted. A total of 98 swallows (58 normal, 40 abnormal) were correlated, and a 96% agreement was found in assessing primary peristalsis. Overall results of fluoroscopic examinations of each subject during all swallows showed complete agreement with those of manometry; segregating the swallows into groups of five showed 92% concordance. Severe tertiary activity was invariably seen with abnormal primary peristalsis at fluoroscopy.

Hypertensive lower esophageal sphincter: what does it mean?

The hypertensive lower esophageal sphincter (LES) (mean LES pressure greater than 45 mm Hg; LES relaxation greater than 75%; normal peristalsis) is a poorly characterized motility disorder associated with chest pain and dysphagia. Therefore, we carried out a multidisciplinary study to assess esophageal pressures and function in 15 symptomatic hypertensive LES patients (3 men, 12 women; mean age, 53 years). On-line computer analysis showed a significant (p less than 0.05) increase in LES pressure (55.5 versus 14.9 mm Hg) and residual pressure (6.8 versus 1.1 mm Hg) as well as a decrease in percentage of LES relaxation (87 versus 93%) in patients compared with age-matched controls. All patients had normal peristalsis but 7 of 15 had nutcracker esophagus (mean distal amplitude, 216 mm Hg). No patient had evidence of impaired liquid transport on barium esophagram. The emptying of solids as assessed by radionuclide scans was normal in 14 of 15 patients. Of the 12 patients who completed both psychological inventories, nine had elevated scores on scales assessing anxiety and somatization. The heterogenous nature of this disorder is illustrated by a patient with a changeable narrowing in the distal esophagus associated with the transient impaction of a marshmallow. Dysphagia but not chest pain improved after pneumatic dilatation. We conclude that the hypertensive LES is a heterogenous disorder. Despite abnormal LES parameters, most patients have normal esophageal function, and frequent psychological abnormalities may contribute to their report of symptoms. A minority have abnormal esophageal transit.

Acid perfusion test: does it have a role in the assessment of non cardiac chest pain?

Using 24 hour pH monitoring as a reference standard, the usefulness of the acid perfusion (AP) test in predicting gastro-oesophageal reflux disease (GORD) was assessed in 71 non-cardiac chest pain (NCCP) patients and 23 endoscopic oesophagitis patients. Of the 71 NCCP patients, 35 had a positive AP test (of whom 20 had an abnormal 24 hour pH) and 36 had a negative AP test (of whom 14 had an abnormal 24 hour pH study). Thus, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the AP test in this group was 59%, 59%, 57%, and 61%, respectively. The corresponding values in the oesophagitis group were 85%, 67%, 94%, and 40%. In the NCCP group when heartburn alone was used as the positive criterion the PPV rose to 74%. When chest pain with or without heartburn was used, however, the PPV dropped to 38%. A 'symptom index' was used to define the number of chest pain episodes that were caused by acid reflux. Only 48% of AP test positive patients had demonstrable acid mediated chest pain. In the NCCP population with a normal oesophageal examination (1) AP test reproduction of chest pain is poorly predictive of GORD; (2) AP test reproduction of heartburn is more predictive of GORD but does not ensure that the chest pain is caused by GORD; (3) a negative AP test does not exclude GORD and (4) only 48% of AP test positive patients have demonstrable acid mediated chest pain. The ambulatory 24 hour pH test may have rendered the AP test obsolete in the assessment of GORD as the cause of NCCP.

Stress induces alteration of esophageal pressures in healthy volunteers and non-cardiac chest pain patients

The present study was designed to explore the relationship between psychological stress and esophageal motility disorders. Nineteen non-cardiac chest pain patients (10 with the nutcracker esophagus and nine with normal baseline manometry) and 20 healthy control subjects were administered two acute stressors: intermittent bursts of white noise and difficult cognitive problems. The results indicated that the esophageal contraction amplitudes and levels of anxiety-related behaviors of non-cardiac chest pain patients and control subjects were significantly greater during the stressors than during baseline periods. All patients demonstrated significantly greater (P less than 0.01) increases in contraction amplitude and anxiety-related behavior during cognitive problems than during the noise stressor. The nutcracker esophagus patients showed a greater increase in contraction amplitude during the problems (23.50 +/- 9.42 mm Hg, X +/- SE) than control subjects (P less than 0.01), while the amplitude changes of chest pain patients with normal baseline manometry were not significantly greater than that of control subjects (9.00 +/- 1.91 mm Hg). The present results identified an increase in contraction amplitude as the primary esophageal response to stress. The possible interaction of esophageal contraction abnormalities, psychological stress, and the perception of chest pain is discussed.

On-line computer analysis of human lower esophageal sphincter relaxation

Lower esophageal sphincter (LES) relaxation is usually interpreted by a subjective, mostly qualitative analysis. We studied sphincter relaxation in humans using a computer program for on-line analysis that provides objective measures of gastric pressure, resting LES pressure, percent of relaxation, residual pressure during relaxation, duration of relaxation, and area of relaxation. The program was validated by comparing computer-analyzed values to mean values obtained from manual readings by five individuals. Excellent correlation was obtained for all standard parameters. The parameters of LES relaxation for both wet and dry swallows were similar using either a carefully placed single recording orifice or a Dent sleeve. The one exception was the duration of LES relaxation, which was significantly shorter with the sleeve. All relaxation parameters and peristaltic velocity were then studied in 10 volunteers during 5 dry and 5 wet swallows under base-line conditions and after both atropine (10 micrograms/kg iv) and bethanechol (40 micrograms/kg sc). These studies showed that LES relaxation is affected by type of swallow (dry vs. wet). Percent of relaxation may not be the best measure of relaxation because it is too dependent on resting pressure. Residual pressure is not dependent on base-line pressure and may better define relaxation. Duration of the relaxation is dependent on the velocity of the peristaltic wave.

The changing faces of the nutcracker esophagus

Although the nutcracker esophagus, characterized by high amplitude peristaltic contractions with mean distal amplitude greater than 180 mm Hg, is the most common esophageal motility disorder associated with noncardiac chest pain, little is known about its natural history. Therefore, we reviewed the manometric tracings of 23 patients with the nutcracker esophagus who had an average of 4.6 studies during a mean period of 32 months. Ten age-matched volunteers with normal baseline manometry who had undergone multiple studies (mean 5.8) over a mean time span of 32 months served as controls. In the 17 nutcracker patients with three or more motility studies, the variability of mean distal amplitudes between studies was 41.9% +/- 4.1 (+/- SE) compared to 27.0% +/- 3.3 for the control subjects (p less than 0.01). Highest distal pressures were noted during the first study in 11 of 17 patients (65%) compared to two of 10 controls (20%). The consistency of the diagnosis of nutcracker esophagus varied considerably: four patients always had high amplitude pressures, three patients only had the nutcracker diagnosis on the initial study, and 10 patients intermittently had pressures in the nutcracker range. Overall, these 17 patients had the diagnosis of the nutcracker esophagus confirmed on only 54% of subsequent studies. Changes in motility patterns were intermittently seen in six of 23 patients: one diffuse spasm and five nonspecific motility disorders. None of the control subjects developed high amplitude contractions or changed their motility pattern on serial testing. The possible pathophysiological implications of the changing faces of the nutcracker esophagus are discussed.

Oral nifedipine in the treatment of noncardiac chest pain in patients with the nutcracker esophagus

Placebo-controlled trials are not available to assess the efficacy of smooth muscle relaxants in the treatment of painful esophageal motility disorders. Therefore, we compared the effects of oral nifedipine (10-30 mg t.i.d.) and placebo in 20 patients (mean age 50 yr) with chronic noncardiac chest pain and the nutcracker esophagus in a 14-week double-blind crossover study. Compared to placebo, nifedipine significantly decreased distal esophageal contraction amplitude (mean +/- SEM, 198 +/- 11 mmHg to 123 +/- 9 mmHg; p less than 0.005), as well as duration and lower esophageal sphincter pressure. Nifedipine, however, was no better than placebo in the relief of daily chest pain frequency, severity, or index (frequency X severity) as assessed by patient diaries. Despite these disappointing results, long-term follow-up (mean, 16.6 mo) suggests these patients do improve. Mean daily chest pain index significantly (p less than 0.005) decreased from 10.3 +/- 2.0 at the beginning of the study to 3.2 +/- 0.8 at follow-up. Prescription drug use and physician visits for chest pain also significantly decreased. Distal esophageal contraction pressures significantly fell during the long-term follow-up but there was poor correlation with chest pain improvement. This study suggests that identification of the esophagus as the cause of chest pain coupled with supportive intervention may be more effective than drug therapy in improving these patients' chest pain.

Esophageal testing of patients with noncardiac chest pain or dysphagia. Results of three years' experience with 1161 patients

Records from 910 patients referred to our clinical esophageal manometry laboratory for evaluation of noncardiac chest pain between January 1983 and December 1985 were reviewed and compared with records from 251 patients referred for dysphagia. Evaluation included baseline esophageal manometry, acid perfusion test, and edrophonium provocation. In the chest-pain group, 655 patients (72%) had normal esophageal motility and 255 (28%) had abnormal motility. Nutcracker esophagus was present in 48% of abnormal tracings, suggesting that it is a manometric marker for noncardiac chest pain. Of the total chest-pain group, 243 patients (27%) had their pain reproduced during provocative testing ("definite" esophageal pain); 192 patients (21%) had baseline manometric abnormalities but no pain during provocative testing ("probable" esophageal chest pain). The highest percentage of positive provocative responses (34%) occurred in patients with nutcracker esophagus on baseline manometry. Manometric abnormalities were statistically commoner (p less than 0.001) in patients with dysphagia, occurring in 53%. Achalasia (36%) and nonspecific esophageal motility disorders (38%) were the commonest abnormalities in this group, with nutcracker esophagus being infrequent (10%).

Pirenzepine and propantheline effects on esophageal pressure responses to bethanechol

Pirenzepine is an antisecretory anticholinergic type drug that has recently been shown to be relatively free of usual anticholinergic side effects on esophageal smooth muscle. It has also been suggested that this drug might release some of the inhibitory control of the esophagus and allow increased muscle contractions. To test this hypothesis, we compared the response of the lower esophageal sphincter (LES) and esophageal peristaltic contractions to bethanechol in 12 healthy controls after background oral doses of placebo, pirenzepine (50 mg), and propantheline (30 mg). After baseline placebo, bethanechol (40 micrograms/kg subcutaneously) produced the expected significant increases in LES pressure and amplitude of peristaltic contractions. Maximal increases were 51.9 +/- 14.9 and 29.5 +/- 7.0%, respectively. Also as expected, propantheline inhibited the cholinergic stimulation from bethanechol, allowing only a 10.1 +/- 13.6% increase in LES pressure and a decrease in peristaltic contraction amplitudes (-44.1 +/- 5.0%) after bethanechol. After background pirenzepine, the responses to bethanechol were intermediate between the other two drugs. A significant increase (44.2 +/- 16.4%) in LES pressure occurred after bethanechol while no significant changes (6.9 +/- 5.8%) were noted in peristaltic amplitudes with this drug. Typical side effects of dry mouth were noted in six of the 12 subjects with propantheline and in only three subjects after pirenzepine. These studies once again confirm the absence of usual anticholinergic side effects with oral pirenzepine compared to oral propantheline in the doses studied. We could find no evidence for a release of cholinergic inhibition after pirenzepine administration.

Oral pirenzepine does not affect esophageal pressures in man

Pirenzepine has been proposed to selectively inhibit gastric acid production. In contrast to classical anticholinergics, pirenzepine does not appear to produce systemic side effects or to strongly inhibit contractions in gastrointestinal tract smooth muscle. This study compares the effects of two doses of pirenzepine (25 and 50 mg per os) with a standard anticholinergic, propantheline, 30 mg per os, and with placebo on esophageal contraction pressures in 12 healthy volunteers in a random double-blind study sequence. No significant change in lower esophageal sphincter pressure (LESP) or in peristaltic pressures occurred with placebo or pirenzepine 25 or 50 mg. However, propantheline produced marked reduction in peristaltic contraction pressures and increased velocity (4 of 12 subjects had complete loss of peristalsis). LESP decrease was almost significant. Seven of 12 subjects experienced dry mouth after propantheline, but none after either dose of pirenzepine or placebo. This study indicates that, as opposed to a classical anticholinergic, pirenzepine does not adversely affect esophageal contraction pressures nor does it have anticholinergic side effects with the oral doses studied.

Nifedipine: a potent inhibitor of contractions in the body of the human esophagus. Studies in healthy volunteers and patients with the nutcracker esophagus

Nifedipine, a calcium channel blocker, inhibits lower esophageal sphincter pressure but has only minimal effect on esophageal contractions. We investigated the effects of nifedipine on esophageal contractions in 5 healthy volunteers and 10 patients with the nutcracker esophagus. Nifedipine (10, 20, 30 mg) or placebo was ingested as capsules in a double-blind design on 4 separate days. In volunteers, mean distal amplitude decreased 16.6%, 38.4%, and 49.0% as the nifedipine dose was increased. These changes were significantly (p less than 0.05) different from the placebo response and were sustained with higher doses. Patients with the nutcracker esophagus had a similar response, decreasing mean distal amplitude significantly (p less than 0.05) by 16.3%, 36.2%, and 54.2%. In both groups, nifedipine also had a significant (p less than 0.05) dose-dependent depressant effect on distal duration, although to a lesser degree than on amplitude. The percent decrease in distal amplitude showed good correlation (p less than 0.01) with plasma nifedipine concentrations at 60 min. These studies suggest nifedipine may be useful in the treatment of motility disorders of the esophageal body.