Evaluation of a tuberculosis screening p r o g r a m at a children's hospital Scott A. Halperin, MD Joanne M. Langley, MD, MSc Halifax, Nova Scotia, Canada
Routine screening of patients for tuberculosis at the time of hospitalization and annual screening of hospital employees continue to be controversial. No data are available concerning tuberculosis screening programs at pediatric facilities. We reviewed the results of patient and employee tuberculosis screening programs in the last decade at the Izaak Walton Killam Hospital for Children. Four (11%) of 37 cases Of tuberculosis were unsuspected until identified by the routine screening of all children at their admission to the hospital. No cases of tuberculosis were identified as a result of the employee screening program. Compliance with both screening programs was less than optimal. Review of programs at other Canadian pediatric centers demonstrated a range of practice. We conclude that routine screening of patients at the time of admission to the hospital and the annual screening of employees are unwarranted at present at our children's hospital. However, discontinuation of routine testing necessitates aggressive contact-tracing by public health authorities of patients with identified cases and periodic reevaluation of costs and benefits to determine whether reintroduction of screening is appropriate. (AJIC AM J INFECTCONTROL1992;20:19-23)
D u r i n g the p a s t several d e c a d e s t h e r e has b e e n a s t e a d y decline in the r a t e of n e w a n d reactiv a t e d cases o f t u b e r c u l o s i s (TB) r e p o r t e d in Cana d a J In 1989 o n l y 1544 cases (5.8 p e r 100,000 p o p u l a t i o n ) w e r e r e p o r t e d . T h e i n c i d e n c e of TB a m o n g C a n a d i a n c h i l d r e n h a s also declined: The r e s u r g e n c e of TB in c e r t a i n areas in the U n i t e d States, 2 p e r h a p s r e l a t e d to the i n c r e a s e in cases a s s o c i a t e d w i t h HIV infection, has n o t o c c u r r e d in C a n a d a . Significant r e g i o n a l v a r i a t i o n in TB i n c i d e n c e is a p p a r e n t (Table 1). The p u r p o s e s of TB s c r e e n i n g p r o g r a m s are the p r e v e n t i o n of t r a n s m i s s i o n b y d e t e c t i n g d i s e a s e a n d the d e t e c t i o n of i n f e c t i o n so t h a t p r o g r e s s i o n
From the Departments of Pediatrics, Community Health and Epidemiqlogy, and Microbiology, Dalhousie University, and the Izaak Walton Killam Hospital for Children, Halifax, Nova Scotia, Canada. Presented in part at the Association for Practitioners of Infection Control 18th Annual Educational Conference and Annual Meeting, May 6-10, 1991, Nashville, Tennessee. Reprint requests: Scott A. Halperin, MD, Izaak Walton Killam Hospital for Children, 5850 University Ave., Halifax, Nova Scotia, B3J 3G9, Canada.
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to a disease s t a t e m a y be p r e v e n t e d P R e c o m m e n d a t i o n s f o r p o p u l a t i o n s c r e e n i n g in c h i l d r e n h a v e b e e n m o d i f i e d f r o m a n n u a l testing 4 to inc l u d e s c r e e n i n g o n l y a m o n g high-risk p o p u l a tions ?.6 T h e r e are n o specific r e c o m m e n d a t i o n s for s c r e e n i n g in p e d i a t r i c hospitals. InStitutional s c r e e n i n g is a d v i s e d if a high p r e v a l e n c e of disease exists in the p o p u l a t i o n , the p o p u l a t i o n is at risk for e x p e r i e n c i n g the disease, the risk of t r a n s m i s s i o n is high, o r y o u n g or i m m u n o s u p p r e s s e d p e r s o n s m a y be i n f e c t e d Y '8 These indications, a l o n g w i t h e v i d e n c e t h a t hospital workers m a y be a t h i g h e r risk t h a n the general popu l a t i o n for t u b e r c u l i n s e r o c o n v e r s i o n , 9'*° are the basis for TB s c r e e n i n g p r o g r a m s involving patients a n d e m p l o y e e s at c h i l d r e n ' s hospitals. In light of t h e d e c l i n i n g i n c i d e n c e of TB in Canada, w e r e e v a l u a t e d the p a t i e n t a n d e m p l o y e e s c r e e n i n g p r o g r a m s at the I z a a k W a l t o n K i l l a m H o s p i t a l for C h i l d r e n (IWK). The p u r p o s e s of the s t u d y w e r e (1) to c o m p a r e the TB s c r e e n i n g prog r a m at I W K w i t h t h o s e in p l a c e at o t h e r child r e n ' s h o s p i t a l s in C a n a d a , (2) to assess the yield 'of the p a t i e n t a n d e m p l o y e e s c r e e n i n g p r o g r a m s at IWK, a n d (3) to d e t e r m i n e w h e t h e r the b u r d e n of illness a s s o c i a t e d w i t h TB in o u r region warr a n t e d c o n t i n u a t i o n of this p r o g r a m . 11'12 19
20
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Halperinand Langley
T a b l e 1. Incidence of TB between 1988 and 1989 in North America (cases per 100,000 population) Area
1988
1989
Canada Maritime provinces* United States
-7.7 3.7 9.1
5.8 2.5 9.5
Data from Laboratory Centre for Disease Controll Ottawa, Canada, 1990. *Maritime provinces of Canada are Nova Scotia, New Brunswick, and Prince Edward Island.
T a b l e 2. Clinical manifestations of disease among 37 children with TB admitted to the IWK Children's Hospital, 1978 and 1988 Disease manifestations
No.
%*
Pulmonary Meningeal Otitic Cutaneous Erythema nodosum No manifestation
23 4 1 1 1 9
62 11 3 3 3 24
*More than 100% total because of two patients with two clinical manifestations (one with pulmonary and erythema nodosum and one with pulmonary and meningitis).
METHODS
The IWK is a 180-bed p r i m a r y and tertiary care university-affiliated pediatric hospital in Halifax, Nova Scotia, Canada. It accepts patients from three Maritime provinces (Nova Scotia, New Brunswick, a n d Prince E d w a r d Island) and less c o m m o n l y accepts patients from Newfoundland. The c o m b i n e d population of the three Maritime provinces in 1.7 million persons. Admission s c r e e n i n g p r o g r a m
In this program, all children older than 1 year of age w h o were considered likely to be hospitalized for more than 48 hours were assessed with a m u l t i p u n c t u r e tuberculin skin test (Tine). A multiple-puncture device was used because a large, low-risk population was being screened? Children with histories of a previous tuberculin test within 1 year, a k n o w n positive reaction to tuberculin, k n o w n active TB, allergic dermatitis, i m m u n o s u p p r e s s i v e therapy, extensive burns, or known allergy to the Tine test material were excluded from screening. Charts of all patients with a discharge diagnosis of TB w h o were seen at IWK from 1978 through 1988 were reviewed for admission diagnosis, clinical presentation, di-
agnostic tests used to confirm TB, and results of a tuberculin (Tine or Mantoux) test. Compliance with the screening p r o g r a m was assessed b y auditing a sample of 100 consecutive hospital discharge records from February 1 to 22, 1989. Records were examined to determine if a m u l t i p u n c t u r e tuberculin test was performed or if a valid contraindication was present. E m p l o y e e screening program
The occupational health records of all employees from 1980 through 1989, inclusive, were reviewed to determine the n u m b e r of tuberculin tests with positive results. All employees were injected with 5 tuberculin units purified protein derivative of tuberculin (PPD) at the time of employment. Tuberculin clinics were held twice yearly; employees without a previous positive test results or known history of TB were asked to have an annual Mantoux tuberculin test. Induration of 10 m m or more was interpreted as a positive test result. TB s c r e e n i n g programs at C a n a d i a n pediatric hospitals "
TB screening programs were c o m p a r e d at all of the 16 university-affiliated pediatric hospitals in Canada. Details of the patient and employee screening programs were obtained by a telephone survey of infection control practitioners and nursing administrators. RESULTS P a t i e n t screening program
A total of 37 cases of tuberculosis were identified at IWK in the 10-year period. Thirty of these cases (81%) occurred in the first 5 years of this period. Median patient age was 8 years, with a uniform distribution through the 1- to 16-year r a n g e . . P u l m o n a r y TB was the most c o m m o n manifestation (Table 2). Mycobacterium tuberculosis was recovered from 10 (27%) of the 37 patients. Gastric aspirate cultures were positive for TB in six patients, spinal fluid cultures were positive in three patients, and cultures of respiratory secretion (sputum and secretions obtained at bronchoscopy) were positive in only one patient. The multipuncture (Tine) test led to the diagnosis of TB in four (11%) of the 37 patients; the admission diagnoses in these cases were'~perfo rated t y m p a n i c m e m b r a n e , chronic otitis media, umbilical hernia, and recurrent aspiration pneu-
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Number1 monia. None of these four patients had a readily identifiable source of infection that might have led to detection of their infection as a result of contract tracing. One child could have had TB detected without general screening during the course of medical evaluation of his recurrent pneumonia. Of the remaining 33 cases of TB, 21 patients (57%) were already known to be infected by virtue of a positive result from an intradermal (Mantoux) test before admission, performed because of the patient's contact with a person known to have TB. In 12 patients (32%) testing was performed because of a clinical suspicion of TB or known contact with a person infected with TB. Among the 100 consecutive discharge records audited to assess compliance with the policy, 65 patients were excluded from testing; 57 (88%) of these patients had valid criteria for exclusion. Thirty-five patients were considered eligible for testing by nursing staff; Tine testing was performed on 18. Thus adherence to the screening policy occurred in 18 (42%) of 43 patients who were truly eligible for testing (35 eligible patients plus 8 patients with invalid exclusions) during the 10 years studied. It was not possible to determine accurately the overall compliance. There were 86,049 admissions to the IWK; 22,000 Tine tests were supplied to nursing units during this period. Allowing for valid exclusions, 37,000 patients admitted should probably have been tested. The quantity of Tine test material used during the study period is consistent with the program compliance rate determined in the audit. Employee screening program
No cases of tuberculous disease were identified by the employee screening program. During the 10-year period 735 new employees were tested. Of these, 160 (22%) had a positive PPD result.oIn 29 (3.9%) of tested employees with a positive PPD result a history of exposure to TB was given; chest radiographs all appeared normal. The remaining 131 positive results (17.8%) occurred in employees previously immunized with BacilleCalmette-Gu6rin (BCG) vaccine. In two of these 131 chest radiography results were abnormal. Subsequent investigation confirmed causes for the abnormalities other than TB. During the 10-year period 2089 PPD tests were administered during the annual screening TB program for all employees. The PPD test result
TB screening in a children's hospital
21
was positive in 582 (27%) of the tests; these employees had all been previously immunized with BCG vaccine. Follow-up chest radiographs appeared normal. If all employees had complied with annual testing, 14,000 intradermal PPD tests would have been administered. Therefore compliance with the screening program was approximately 15% (2089/14,000). TB screening programs at Canadian pediatric hospitals
All of the other 15 university-affiliated hospital pediatric units in Canada have discontinued admission screening. All now screen selected patients (contacts of known cases, high-risk groups). All hospitals screen newemployees; 14 use the intradermal Mantoux test and one uses the multipuncture Tine test. Seven of the 15 hospitals screen employees yearly, one screens employees every 5 years, and one screens employees only in selected patient care areas. The remaining six hospitals test only employees who have had contact with a person with TB. DISCUSSION
Routine screening of children for TB continues to be controversial, and divergent r e c o m m e n dations persist. The Centers for Disease Control recommends screening children in high-risk populations, including contacts of persons with TB, foreign-born children, and children from low-income groups? The American Academy of Pediatrics no longer recommends annual screening for low-risk children but suggests testing at 12 to 15 months of age, before school entry, and during adolescence? However, most TB cases in children can be identified by contact tracing of adults with TB, rather than by general screening programs. 13-15 Several investigators continue to recommend screening programs because of their seemingly low cost relative to other health programs and the importance of identifying even small numbers of cases. 16,~7 The benefits of screening programs for high-risk populations are not contestedJ 72' Little information is available on the benefits of routine screening for TB on hospital admission. TB screening at the time of admission to long-term care facilities has been recommended because of reports of high prevalence and outbreaks of TB at certain institutions. 22'23 No studies have demonstrated a clear benefit in screening pediatric admissions. The burden of illness
22
AJIC February 1992
Halperinand Langley
m a y w a r r a n t s c r e e n i n g in h o s p i t a l s t h a t serve h i g h - r i s k p o p u l a t i o n s , is b u t this is not t r u e in areas w h e r e TB is u n c o m m o n . 24 In o u r s t u d y o n l y four c a s e s f o u n d d u r i n g a 10-year p e r i o d w o u l d not h a v e b e e n d e t e c t e d b y t e s t i n g high-risk patients, c o n t a c t s of p e r s o n s k n o w n to h a v e TB, o r p a t i e n t s w i t h a n illness c o m p a t i b l e w i t h a diagnosis of TB. O u r c a l c u l a t e d r a t e of 0.18 cases d e t e c t e d p e r 1000 tests m a y be c o n s e r v a t i v e l y b i a s e d b y t h e a p p r o x i m a t i o n of the d e n o m i n a t o r ; h o w e v e r , it is well b e l o w the r a t e for w h i c h a TB s c r e e n i n g p r o g r a m is r e c o m m e n d e d b y the Centers f o r Disease Control. 6 T h e r e a s o n for the cont i n u i n g d e c l i n e in TB r a t e s in o u r region, c o m p a r e d w i t h o t h e r s , m a y be a l o w e r i n c i d e n c e of AIDS ( a v e r a g e 5 n e w cases p e r 100,000 p o p u l a tion p e r y e a r in N o v a Scotia) or a m o r e s t a b l e population. P e d i a t r i c h o s p i t a l e m p l o y e e s c r e e n i n g prog r a m s are still w i d e l y u s e d in C a n a d a . H o s p i t a l policies v a r y t h r o u g h o u t the U n i t e d States23.2s-27; d a t a a r e n o t a v a i l a b l e c o n c e r n i n g p e d i a t r i c facilities. O c c u p a t i o n a l risk is n o t as m u c h a conc e r n in p e d i a t r i c h o s p i t a l s as in a d u l t h o s p i t a l s b e c u a s e c h i l d r e n r a r e l y h a v e e i t h e r sufficient c o u g h i n g o r sufficient c a v i t a r y disease to gene r a t e v i a b l e o r g a n i s m s . 28.29 In s u c h c i r c u m s t a n c e s the i n c i d e n c e of TB in h o s p i t a l e m p l o y e e s p r o b a b l y reflects the i n c i d e n c e in the s u r r o u n d ing c o m m u n i t y , r a t h e r t h a n a n o c c u p a t i o n a l risk.24,30,31 In o u r s t u d y the y i e l d f r o m TB s c r e e n i n g was negligible. If the a n n u a l r a t e of 5 cases of TB p e r 100,000 C a n a d i a n s w e r e to h o l d t r u e for o u r emp l o y e e s a n d if t h e r e w e r e 100% c o m p l i a n c e w i t h a n n u a l testing, w e c o u l d e x p e c t to i d e n t i f y o n e case of TB e v e r y 14.3 years. G i v e n a n e s t i m a t e d cost p e r test of $6 to $11 (in U.S. dollars), 24 s u c h a p r o g r a m w o u l d cost f r o m $144,144 to $264,264 per c a s e d e t e c t e d . W i t h o u r p a r t i c i p a t i o n r a t e of 15% in the a n n u a l e m p l o y e e s c r e e n i n g prog r a m s , one case w o u l d b e d e t e c t e d e v e r y 96 y e a r s at o u r h o s p i t a l . More t h a n $21,200 was s p e n t o n Tine test m a t e r i a l a l o n e at o u r h o s p i t a l to d e t e c t the f o u r cases of TB f o u n d b y a d m i s s i o n screening. On t h e basis of the e p i d e m i o l o g i c c h a r a c t e r of TB in o u r r e g i o n a n d the results of this review, we c o n c l u d e d t h a t t h e r e was m i n i m a l v a l u e in c o n t i n u i n g TB s c r e e n i n g p r o g r a m s at this t i m e . S i m i l a r c o n c l u s i o n s s e e m to h a v e b e e n m a d e b y o t h e r p e d i a t r i c h o s p i t a l s in C a n a d a . I n s t e a d , testing of p e r s o n s in s e l e c t e d high-risk groups, contacts of TB cases, a n d c h i l d r e n w i t h signs or
s y m p t o m s c o m p a t i b l e w i t h a diagnosis of TB is now performed with an intradermal Mantoux t e s t . E m p l o y e e s a r e skin t e s t e d at the t i m e of employment and after contact with a person with TB. S u c h a n a p p r o a c h r e q u i r e s e m p l o y e e educ a t i o n a b o u t the r e s p o n s i b i l i t y for b e i n g t e s t e d a f t e r e x p o s u r e to a p e r s o n w i t h TB, p e r i o d i c reeva l u a t i o n b a s e d o n o n g o i n g s u r v e i l l a n c e of the c o m m u n i t y a n d t h e h o s p i t a l , a n d t h o r o u g h cont a c t t r a c i n g b y p u b l i c h e a l t h a u t h o r i t i e s of persons i d e n t i f i e d as h a v i n g TB. In s o m e localities s c r e e n i n g m a y be m a n d a t e d b y legislation, b u t it is n o t r e q u i r e d in o u r p r o v i n c e . TB c o n t i n u e s to b e a m a j o r p r o b l e m in N o r t h America. A trend toward an uneven geographic d i s t r i b u t i o n of TB has b e c o m e a p p a r e n t in the last d e c a d e . TB h a s b e e n v i r t u a l l y e r a d i c a t e d in s o m e p o p u l a t i o n s a n d is o n the r i s e in others. G l o b a l r e c o m m e n d a t i o n s for TB s c r e e n i n g are of no benefit. 32 R e c o m m e n d a t i o n s b a s e d o n local e p i d e m i o l o g i c c o n s i d e r a t i o n s are m o r e a p p r o p r i a t e a n d a l l o w m o r e r a t i o n a l use of r e s o u r c e s . R o u t i n e s c r e e n i n g for TB of c h i l d r e n a d m i t t e d to t h e h o s p i t a l a n d y e a r l y e m p l o y e e s c r e e n i n g prog r a m s at p e d i a t r i c h o s p i t a l s in a r e a s w i t h low i n c i d e n c e of TB a r e u n n e c e s s a r y . We thank Margorie MacKenzie and Evelyn Crook for their review of Occupational Health records, Valerie Shaffner for her review of medical records, and Christine Fern for preparation of the manuscript.
References
1. Gaudette LA. Tuberculosis in Canada--1986. Can Dis Wkly Rep 1988;14:27-8. 2. Centers for Disease Control. Update: tuberculosis elimination-United States. MMWR 1990;39:153-6. 3. American Thoracic Society. Control of tuberculosis. Am Rev Respir Dis 1983;128:336-42. 4. American Academy of Pediatrics, Section on Diseases of the Chest. The tuberculin test. Pediatrics 1974;54:650-2. 5. American Academy Of Pediatrics. Tuberculosis. In: Report of the committee on infectious diseases. Redbook. Evanston: American Academy of Pediatrics, 1988:429-47. 6. Centers for Disease Control. Screening for tuberculosis and tuberculous infection in high-risk populations. MMWR 1990;39(RR-8):1-12. 7. Committee on Public Health Issues. Public health issues in control of tuberculosis: surveillance techniques and the role of health care providers. Chest 1985; 2(Suppl): 135S-8S. 8. Dooley SW Jr, Castro KG, Hutton MD, Mullan RJ, Polder JA, Snider DE Jr. Guidelines for preventing the transmission of tuberculosis in health-care settings, with special focus on HIV-related issues. MMWR 1990;39(RR! 7): 1-29. 9. Barrett-Connor E. The epidemiology of tuberculosis in physicians. JAMA 1979;241:33-8.
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10. Levine I. Tuberculosis risk in students of nursing. Arch Intern Med 1968;121:545-8. 11. Fletcher RH, Fletcher SW, Wagner EH. Clinical epidemiology--the essentials. Baltimore: Williams and Wilkins, 1982. 12. Cadman D, Chambers L, Feldman W, Sackett D. Assessing the effectiveness of community screening programs. JAMA 1984;251 : 1580-5. 13. Edwards PQ. Tuberculin testing of children. Pediatrics 1974;54:628-30. 14. Nolan RJ. Childhood tuberculosis in North Carolina: a study of the opportunities for intervention in the transmission of tuberculosis to children. Am J Public Health 1986;76:26-30. 15. Bloch AB, Snider DE. How much tuberculosis in children must we accept? Am J Public Health 1986;76:14-5. 16. Kendig EL Jr. Tuberculin testing in the young. Compr Ther 1986;12:66-70. 17. Kraut JR, Christoffel KK, Berkelhamer JE, Boddie-Willis C. Assessment of tuberculin screening in an urban pediatric clinic. Pediatrics 1979;64:856-9. 18. Inselman LS, E1-Maraghy NB, Evans HE. Apparent resurgence of tuberculosis in urban children. Pediatrics 1981;68:647-9. 19. Perez-Stable EJ, Levin R, Pineda A, Slutkin G. Tuberculin skin test reactivity and conversions in United States- and foreign-born Latino children. Pediatr Infect Dis J 1985;4:476-9. 20. Nemir RL, Krasinski K. Tuberculosis in children and adolescents in the 1980s. Pediatr Infect Dis J 1988;7: 375-9. 21. Snider DE, Rieder HL, Combs D, Bloch AB, Hayden CH,
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Routine screening of patients for tuberculosis at the time of hospitalization and annual screening of hospital employees continue to be controversial. No data are available concerning tuberculosis screening programs at pediatric facilities. We reviewed the results of patient and employee tuberculosis screening programs in the last decade at the Izaak Walton Killam Hospital for Children. Four (11%) of 37 cases Of tuberculosis were unsuspected until identified by the routine screening of all children at their admission to the hospital. No cases of tuberculosis were identified as a result of the employee screening program. Compliance with both screening programs was less than optimal. Review of programs at other Canadian pediatric centers demonstrated a range of practice. We conclude that routine screening of patients at the time of admission to the hospital and the annual screening of employees are unwarranted at present at our children's hospital. However, discontinuation of routine testing necessitates aggressive contact-tracing by public health authorities of patients with identified cases and periodic reevaluation of costs and benefits to determine whether reintroduction of screening is appropriate. (AJIC AM J INFECTCONTROL1992;20:19-23)
D u r i n g the p a s t several d e c a d e s t h e r e has b e e n a s t e a d y decline in the r a t e of n e w a n d reactiv a t e d cases o f t u b e r c u l o s i s (TB) r e p o r t e d in Cana d a J In 1989 o n l y 1544 cases (5.8 p e r 100,000 p o p u l a t i o n ) w e r e r e p o r t e d . T h e i n c i d e n c e of TB a m o n g C a n a d i a n c h i l d r e n h a s also declined: The r e s u r g e n c e of TB in c e r t a i n areas in the U n i t e d States, 2 p e r h a p s r e l a t e d to the i n c r e a s e in cases a s s o c i a t e d w i t h HIV infection, has n o t o c c u r r e d in C a n a d a . Significant r e g i o n a l v a r i a t i o n in TB i n c i d e n c e is a p p a r e n t (Table 1). The p u r p o s e s of TB s c r e e n i n g p r o g r a m s are the p r e v e n t i o n of t r a n s m i s s i o n b y d e t e c t i n g d i s e a s e a n d the d e t e c t i o n of i n f e c t i o n so t h a t p r o g r e s s i o n
From the Departments of Pediatrics, Community Health and Epidemiqlogy, and Microbiology, Dalhousie University, and the Izaak Walton Killam Hospital for Children, Halifax, Nova Scotia, Canada. Presented in part at the Association for Practitioners of Infection Control 18th Annual Educational Conference and Annual Meeting, May 6-10, 1991, Nashville, Tennessee. Reprint requests: Scott A. Halperin, MD, Izaak Walton Killam Hospital for Children, 5850 University Ave., Halifax, Nova Scotia, B3J 3G9, Canada.
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to a disease s t a t e m a y be p r e v e n t e d P R e c o m m e n d a t i o n s f o r p o p u l a t i o n s c r e e n i n g in c h i l d r e n h a v e b e e n m o d i f i e d f r o m a n n u a l testing 4 to inc l u d e s c r e e n i n g o n l y a m o n g high-risk p o p u l a tions ?.6 T h e r e are n o specific r e c o m m e n d a t i o n s for s c r e e n i n g in p e d i a t r i c hospitals. InStitutional s c r e e n i n g is a d v i s e d if a high p r e v a l e n c e of disease exists in the p o p u l a t i o n , the p o p u l a t i o n is at risk for e x p e r i e n c i n g the disease, the risk of t r a n s m i s s i o n is high, o r y o u n g or i m m u n o s u p p r e s s e d p e r s o n s m a y be i n f e c t e d Y '8 These indications, a l o n g w i t h e v i d e n c e t h a t hospital workers m a y be a t h i g h e r risk t h a n the general popu l a t i o n for t u b e r c u l i n s e r o c o n v e r s i o n , 9'*° are the basis for TB s c r e e n i n g p r o g r a m s involving patients a n d e m p l o y e e s at c h i l d r e n ' s hospitals. In light of t h e d e c l i n i n g i n c i d e n c e of TB in Canada, w e r e e v a l u a t e d the p a t i e n t a n d e m p l o y e e s c r e e n i n g p r o g r a m s at the I z a a k W a l t o n K i l l a m H o s p i t a l for C h i l d r e n (IWK). The p u r p o s e s of the s t u d y w e r e (1) to c o m p a r e the TB s c r e e n i n g prog r a m at I W K w i t h t h o s e in p l a c e at o t h e r child r e n ' s h o s p i t a l s in C a n a d a , (2) to assess the yield 'of the p a t i e n t a n d e m p l o y e e s c r e e n i n g p r o g r a m s at IWK, a n d (3) to d e t e r m i n e w h e t h e r the b u r d e n of illness a s s o c i a t e d w i t h TB in o u r region warr a n t e d c o n t i n u a t i o n of this p r o g r a m . 11'12 19
20
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T a b l e 1. Incidence of TB between 1988 and 1989 in North America (cases per 100,000 population) Area
1988
1989
Canada Maritime provinces* United States
-7.7 3.7 9.1
5.8 2.5 9.5
Data from Laboratory Centre for Disease Controll Ottawa, Canada, 1990. *Maritime provinces of Canada are Nova Scotia, New Brunswick, and Prince Edward Island.
T a b l e 2. Clinical manifestations of disease among 37 children with TB admitted to the IWK Children's Hospital, 1978 and 1988 Disease manifestations
No.
%*
Pulmonary Meningeal Otitic Cutaneous Erythema nodosum No manifestation
23 4 1 1 1 9
62 11 3 3 3 24
*More than 100% total because of two patients with two clinical manifestations (one with pulmonary and erythema nodosum and one with pulmonary and meningitis).
METHODS
The IWK is a 180-bed p r i m a r y and tertiary care university-affiliated pediatric hospital in Halifax, Nova Scotia, Canada. It accepts patients from three Maritime provinces (Nova Scotia, New Brunswick, a n d Prince E d w a r d Island) and less c o m m o n l y accepts patients from Newfoundland. The c o m b i n e d population of the three Maritime provinces in 1.7 million persons. Admission s c r e e n i n g p r o g r a m
In this program, all children older than 1 year of age w h o were considered likely to be hospitalized for more than 48 hours were assessed with a m u l t i p u n c t u r e tuberculin skin test (Tine). A multiple-puncture device was used because a large, low-risk population was being screened? Children with histories of a previous tuberculin test within 1 year, a k n o w n positive reaction to tuberculin, k n o w n active TB, allergic dermatitis, i m m u n o s u p p r e s s i v e therapy, extensive burns, or known allergy to the Tine test material were excluded from screening. Charts of all patients with a discharge diagnosis of TB w h o were seen at IWK from 1978 through 1988 were reviewed for admission diagnosis, clinical presentation, di-
agnostic tests used to confirm TB, and results of a tuberculin (Tine or Mantoux) test. Compliance with the screening p r o g r a m was assessed b y auditing a sample of 100 consecutive hospital discharge records from February 1 to 22, 1989. Records were examined to determine if a m u l t i p u n c t u r e tuberculin test was performed or if a valid contraindication was present. E m p l o y e e screening program
The occupational health records of all employees from 1980 through 1989, inclusive, were reviewed to determine the n u m b e r of tuberculin tests with positive results. All employees were injected with 5 tuberculin units purified protein derivative of tuberculin (PPD) at the time of employment. Tuberculin clinics were held twice yearly; employees without a previous positive test results or known history of TB were asked to have an annual Mantoux tuberculin test. Induration of 10 m m or more was interpreted as a positive test result. TB s c r e e n i n g programs at C a n a d i a n pediatric hospitals "
TB screening programs were c o m p a r e d at all of the 16 university-affiliated pediatric hospitals in Canada. Details of the patient and employee screening programs were obtained by a telephone survey of infection control practitioners and nursing administrators. RESULTS P a t i e n t screening program
A total of 37 cases of tuberculosis were identified at IWK in the 10-year period. Thirty of these cases (81%) occurred in the first 5 years of this period. Median patient age was 8 years, with a uniform distribution through the 1- to 16-year r a n g e . . P u l m o n a r y TB was the most c o m m o n manifestation (Table 2). Mycobacterium tuberculosis was recovered from 10 (27%) of the 37 patients. Gastric aspirate cultures were positive for TB in six patients, spinal fluid cultures were positive in three patients, and cultures of respiratory secretion (sputum and secretions obtained at bronchoscopy) were positive in only one patient. The multipuncture (Tine) test led to the diagnosis of TB in four (11%) of the 37 patients; the admission diagnoses in these cases were'~perfo rated t y m p a n i c m e m b r a n e , chronic otitis media, umbilical hernia, and recurrent aspiration pneu-
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Number1 monia. None of these four patients had a readily identifiable source of infection that might have led to detection of their infection as a result of contract tracing. One child could have had TB detected without general screening during the course of medical evaluation of his recurrent pneumonia. Of the remaining 33 cases of TB, 21 patients (57%) were already known to be infected by virtue of a positive result from an intradermal (Mantoux) test before admission, performed because of the patient's contact with a person known to have TB. In 12 patients (32%) testing was performed because of a clinical suspicion of TB or known contact with a person infected with TB. Among the 100 consecutive discharge records audited to assess compliance with the policy, 65 patients were excluded from testing; 57 (88%) of these patients had valid criteria for exclusion. Thirty-five patients were considered eligible for testing by nursing staff; Tine testing was performed on 18. Thus adherence to the screening policy occurred in 18 (42%) of 43 patients who were truly eligible for testing (35 eligible patients plus 8 patients with invalid exclusions) during the 10 years studied. It was not possible to determine accurately the overall compliance. There were 86,049 admissions to the IWK; 22,000 Tine tests were supplied to nursing units during this period. Allowing for valid exclusions, 37,000 patients admitted should probably have been tested. The quantity of Tine test material used during the study period is consistent with the program compliance rate determined in the audit. Employee screening program
No cases of tuberculous disease were identified by the employee screening program. During the 10-year period 735 new employees were tested. Of these, 160 (22%) had a positive PPD result.oIn 29 (3.9%) of tested employees with a positive PPD result a history of exposure to TB was given; chest radiographs all appeared normal. The remaining 131 positive results (17.8%) occurred in employees previously immunized with BacilleCalmette-Gu6rin (BCG) vaccine. In two of these 131 chest radiography results were abnormal. Subsequent investigation confirmed causes for the abnormalities other than TB. During the 10-year period 2089 PPD tests were administered during the annual screening TB program for all employees. The PPD test result
TB screening in a children's hospital
21
was positive in 582 (27%) of the tests; these employees had all been previously immunized with BCG vaccine. Follow-up chest radiographs appeared normal. If all employees had complied with annual testing, 14,000 intradermal PPD tests would have been administered. Therefore compliance with the screening program was approximately 15% (2089/14,000). TB screening programs at Canadian pediatric hospitals
All of the other 15 university-affiliated hospital pediatric units in Canada have discontinued admission screening. All now screen selected patients (contacts of known cases, high-risk groups). All hospitals screen newemployees; 14 use the intradermal Mantoux test and one uses the multipuncture Tine test. Seven of the 15 hospitals screen employees yearly, one screens employees every 5 years, and one screens employees only in selected patient care areas. The remaining six hospitals test only employees who have had contact with a person with TB. DISCUSSION
Routine screening of children for TB continues to be controversial, and divergent r e c o m m e n dations persist. The Centers for Disease Control recommends screening children in high-risk populations, including contacts of persons with TB, foreign-born children, and children from low-income groups? The American Academy of Pediatrics no longer recommends annual screening for low-risk children but suggests testing at 12 to 15 months of age, before school entry, and during adolescence? However, most TB cases in children can be identified by contact tracing of adults with TB, rather than by general screening programs. 13-15 Several investigators continue to recommend screening programs because of their seemingly low cost relative to other health programs and the importance of identifying even small numbers of cases. 16,~7 The benefits of screening programs for high-risk populations are not contestedJ 72' Little information is available on the benefits of routine screening for TB on hospital admission. TB screening at the time of admission to long-term care facilities has been recommended because of reports of high prevalence and outbreaks of TB at certain institutions. 22'23 No studies have demonstrated a clear benefit in screening pediatric admissions. The burden of illness
22
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Halperinand Langley
m a y w a r r a n t s c r e e n i n g in h o s p i t a l s t h a t serve h i g h - r i s k p o p u l a t i o n s , is b u t this is not t r u e in areas w h e r e TB is u n c o m m o n . 24 In o u r s t u d y o n l y four c a s e s f o u n d d u r i n g a 10-year p e r i o d w o u l d not h a v e b e e n d e t e c t e d b y t e s t i n g high-risk patients, c o n t a c t s of p e r s o n s k n o w n to h a v e TB, o r p a t i e n t s w i t h a n illness c o m p a t i b l e w i t h a diagnosis of TB. O u r c a l c u l a t e d r a t e of 0.18 cases d e t e c t e d p e r 1000 tests m a y be c o n s e r v a t i v e l y b i a s e d b y t h e a p p r o x i m a t i o n of the d e n o m i n a t o r ; h o w e v e r , it is well b e l o w the r a t e for w h i c h a TB s c r e e n i n g p r o g r a m is r e c o m m e n d e d b y the Centers f o r Disease Control. 6 T h e r e a s o n for the cont i n u i n g d e c l i n e in TB r a t e s in o u r region, c o m p a r e d w i t h o t h e r s , m a y be a l o w e r i n c i d e n c e of AIDS ( a v e r a g e 5 n e w cases p e r 100,000 p o p u l a tion p e r y e a r in N o v a Scotia) or a m o r e s t a b l e population. P e d i a t r i c h o s p i t a l e m p l o y e e s c r e e n i n g prog r a m s are still w i d e l y u s e d in C a n a d a . H o s p i t a l policies v a r y t h r o u g h o u t the U n i t e d States23.2s-27; d a t a a r e n o t a v a i l a b l e c o n c e r n i n g p e d i a t r i c facilities. O c c u p a t i o n a l risk is n o t as m u c h a conc e r n in p e d i a t r i c h o s p i t a l s as in a d u l t h o s p i t a l s b e c u a s e c h i l d r e n r a r e l y h a v e e i t h e r sufficient c o u g h i n g o r sufficient c a v i t a r y disease to gene r a t e v i a b l e o r g a n i s m s . 28.29 In s u c h c i r c u m s t a n c e s the i n c i d e n c e of TB in h o s p i t a l e m p l o y e e s p r o b a b l y reflects the i n c i d e n c e in the s u r r o u n d ing c o m m u n i t y , r a t h e r t h a n a n o c c u p a t i o n a l risk.24,30,31 In o u r s t u d y the y i e l d f r o m TB s c r e e n i n g was negligible. If the a n n u a l r a t e of 5 cases of TB p e r 100,000 C a n a d i a n s w e r e to h o l d t r u e for o u r emp l o y e e s a n d if t h e r e w e r e 100% c o m p l i a n c e w i t h a n n u a l testing, w e c o u l d e x p e c t to i d e n t i f y o n e case of TB e v e r y 14.3 years. G i v e n a n e s t i m a t e d cost p e r test of $6 to $11 (in U.S. dollars), 24 s u c h a p r o g r a m w o u l d cost f r o m $144,144 to $264,264 per c a s e d e t e c t e d . W i t h o u r p a r t i c i p a t i o n r a t e of 15% in the a n n u a l e m p l o y e e s c r e e n i n g prog r a m s , one case w o u l d b e d e t e c t e d e v e r y 96 y e a r s at o u r h o s p i t a l . More t h a n $21,200 was s p e n t o n Tine test m a t e r i a l a l o n e at o u r h o s p i t a l to d e t e c t the f o u r cases of TB f o u n d b y a d m i s s i o n screening. On t h e basis of the e p i d e m i o l o g i c c h a r a c t e r of TB in o u r r e g i o n a n d the results of this review, we c o n c l u d e d t h a t t h e r e was m i n i m a l v a l u e in c o n t i n u i n g TB s c r e e n i n g p r o g r a m s at this t i m e . S i m i l a r c o n c l u s i o n s s e e m to h a v e b e e n m a d e b y o t h e r p e d i a t r i c h o s p i t a l s in C a n a d a . I n s t e a d , testing of p e r s o n s in s e l e c t e d high-risk groups, contacts of TB cases, a n d c h i l d r e n w i t h signs or
s y m p t o m s c o m p a t i b l e w i t h a diagnosis of TB is now performed with an intradermal Mantoux t e s t . E m p l o y e e s a r e skin t e s t e d at the t i m e of employment and after contact with a person with TB. S u c h a n a p p r o a c h r e q u i r e s e m p l o y e e educ a t i o n a b o u t the r e s p o n s i b i l i t y for b e i n g t e s t e d a f t e r e x p o s u r e to a p e r s o n w i t h TB, p e r i o d i c reeva l u a t i o n b a s e d o n o n g o i n g s u r v e i l l a n c e of the c o m m u n i t y a n d t h e h o s p i t a l , a n d t h o r o u g h cont a c t t r a c i n g b y p u b l i c h e a l t h a u t h o r i t i e s of persons i d e n t i f i e d as h a v i n g TB. In s o m e localities s c r e e n i n g m a y be m a n d a t e d b y legislation, b u t it is n o t r e q u i r e d in o u r p r o v i n c e . TB c o n t i n u e s to b e a m a j o r p r o b l e m in N o r t h America. A trend toward an uneven geographic d i s t r i b u t i o n of TB has b e c o m e a p p a r e n t in the last d e c a d e . TB h a s b e e n v i r t u a l l y e r a d i c a t e d in s o m e p o p u l a t i o n s a n d is o n the r i s e in others. G l o b a l r e c o m m e n d a t i o n s for TB s c r e e n i n g are of no benefit. 32 R e c o m m e n d a t i o n s b a s e d o n local e p i d e m i o l o g i c c o n s i d e r a t i o n s are m o r e a p p r o p r i a t e a n d a l l o w m o r e r a t i o n a l use of r e s o u r c e s . R o u t i n e s c r e e n i n g for TB of c h i l d r e n a d m i t t e d to t h e h o s p i t a l a n d y e a r l y e m p l o y e e s c r e e n i n g prog r a m s at p e d i a t r i c h o s p i t a l s in a r e a s w i t h low i n c i d e n c e of TB a r e u n n e c e s s a r y . We thank Margorie MacKenzie and Evelyn Crook for their review of Occupational Health records, Valerie Shaffner for her review of medical records, and Christine Fern for preparation of the manuscript.
References
1. Gaudette LA. Tuberculosis in Canada--1986. Can Dis Wkly Rep 1988;14:27-8. 2. Centers for Disease Control. Update: tuberculosis elimination-United States. MMWR 1990;39:153-6. 3. American Thoracic Society. Control of tuberculosis. Am Rev Respir Dis 1983;128:336-42. 4. American Academy of Pediatrics, Section on Diseases of the Chest. The tuberculin test. Pediatrics 1974;54:650-2. 5. American Academy Of Pediatrics. Tuberculosis. In: Report of the committee on infectious diseases. Redbook. Evanston: American Academy of Pediatrics, 1988:429-47. 6. Centers for Disease Control. Screening for tuberculosis and tuberculous infection in high-risk populations. MMWR 1990;39(RR-8):1-12. 7. Committee on Public Health Issues. Public health issues in control of tuberculosis: surveillance techniques and the role of health care providers. Chest 1985; 2(Suppl): 135S-8S. 8. Dooley SW Jr, Castro KG, Hutton MD, Mullan RJ, Polder JA, Snider DE Jr. Guidelines for preventing the transmission of tuberculosis in health-care settings, with special focus on HIV-related issues. MMWR 1990;39(RR! 7): 1-29. 9. Barrett-Connor E. The epidemiology of tuberculosis in physicians. JAMA 1979;241:33-8.
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10. Levine I. Tuberculosis risk in students of nursing. Arch Intern Med 1968;121:545-8. 11. Fletcher RH, Fletcher SW, Wagner EH. Clinical epidemiology--the essentials. Baltimore: Williams and Wilkins, 1982. 12. Cadman D, Chambers L, Feldman W, Sackett D. Assessing the effectiveness of community screening programs. JAMA 1984;251 : 1580-5. 13. Edwards PQ. Tuberculin testing of children. Pediatrics 1974;54:628-30. 14. Nolan RJ. Childhood tuberculosis in North Carolina: a study of the opportunities for intervention in the transmission of tuberculosis to children. Am J Public Health 1986;76:26-30. 15. Bloch AB, Snider DE. How much tuberculosis in children must we accept? Am J Public Health 1986;76:14-5. 16. Kendig EL Jr. Tuberculin testing in the young. Compr Ther 1986;12:66-70. 17. Kraut JR, Christoffel KK, Berkelhamer JE, Boddie-Willis C. Assessment of tuberculin screening in an urban pediatric clinic. Pediatrics 1979;64:856-9. 18. Inselman LS, E1-Maraghy NB, Evans HE. Apparent resurgence of tuberculosis in urban children. Pediatrics 1981;68:647-9. 19. Perez-Stable EJ, Levin R, Pineda A, Slutkin G. Tuberculin skin test reactivity and conversions in United States- and foreign-born Latino children. Pediatr Infect Dis J 1985;4:476-9. 20. Nemir RL, Krasinski K. Tuberculosis in children and adolescents in the 1980s. Pediatr Infect Dis J 1988;7: 375-9. 21. Snider DE, Rieder HL, Combs D, Bloch AB, Hayden CH,
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