Acta Neuroehirurgica 32, 247--250 (1975) 9 b y Springer-Verlag 1975

D e p a r t m e n t of Neurology, University of Helsinki, Finland

Epidemiology of Chronic Subdural Haematoma By R. F o g e l h o l m a n d O. Waltimo

Summary During the seven year period 1967-1973 a total of 64 residents of the City of Helsinki were diagnosed as having chronic subdural haematomas. F o r t y of the patients were diagnosed during life at the Departments of Neurology and Neurosurgery, University of ttelsinki, and treated surgically. Twenty four were diagnosed at autopsy at the D e p a r t m e n t of Forensic Medicine, University of ttelsinki, a,t which the autopsies in virtually all cases of subdural h a e m a t o m a in Helsinki are performed. The total of 64 cases gives an incidence of 1.72/100,000/year in the average population, the incidence increasing steeply with advancing age up to 7.35/100,000/year in the age group 70-79 years.

Introduction I n t h e l i t e r a t u r e o n l y s c a n t y i n f o r m a t i o n is a v a i l a b l e on t h e incidence of chronic s u b d u r a l h a e m a t o m a . E e h l i n et al. (1956) s t a t e d t h a t in a b o u t 1 ~o of all cases of h e a d i n j u r y s u b d u r a l h a e m a t o m a will develop as a complication. One in 4 of the 300 h a e m a t o m a s t h e y r e p o r t e d was a chronic one. K l u g et al. (I961) f o u n d in 3,901 eases of closed eraniocerebral t r a u m a only 3 (0.08 %) who s u b s e q u e n t l y d e v e l o p e d a chronic s u b d u r a l h a e m a t o m a . W e b e r (1969) e s t i m a t e d t h e incidence to be l - 2 / 1 0 0 , 0 0 0 / y e a r in a Swiss p o p u l a t i o n . I n order to get an e s t i m a t e for F i n l a n d we h a v e analyged t h e cases of chronic s u b d u r a l h a e m a t o m a in residents of Helsinki b y collecting d a t a of b o t h clinically diagnosed cases a n d those d e t e c t e d a t a u t o p s y .

Material and Methods During the years from 1967 to 1973 a total of 40 patients with chronic subdural haematoma, resident in Helsinki, were examined and operated on at the Departments of Neurology and Neurosurgery, University of He]sinki.

The D e p a r t m e n t of Neurosurgery is the only clinic in I-Ielsinki where operations for subdural h a e m a t o m a are performed. H a e m a t o m a s were

248

g . Fogelholm and O. Waltimo:

considered to be chronic if they were contained within well formed membranes. During the same period a total of 24 eases with chronic subdural haematomas were discovered at autopsy at the Department of Forensic Medicine, University of ttelsinki. These 24 cases were traced by perusing the files of about 10,000 autopsies. Haematomas which were brown, yellow, or grey in colour, which were attached to the dura, and which measured more than 5 m m in thickness, were considered to be chronic. Table 1. Age and Sex Distribution oJ the Material Age in years Sex

Total 20-29

30-39

40-49

50-59

60-69

70-79

80-

6 1

10 1

9 2

4 2

---

33 7

Diagnosed

during

Men Women

1 --

Diagnosed

at autopsy

Men Women

---

1

2

5

1

3

--

12

1

2

1

2

3

3

12

1

6

17

14

12

3

64

Total

life 3 1

ll

Results

The t o t a l n u m b e r of p a t i e n t s with chronic s u b d u r a l h a e m a t o m a a n d resident in tIelsinki d u r i n g the period from 1967-73 was 64. A b o u t half the subjects were 60 years of age or older, a n d 19 (30~o) were women. The age a n d sex d i s t r i b u t i o n of the m a t e r i a l is shown i n Table 1. I n the p o s t m o r t e m eases the correct diagnosis h a d been suspected in only 2 cases before autopsy. Six of the a u t o p s y subjects h a d been f o u n d dead ~t their homes or elsewhere, nine died soon after arrival at hospital before special e x a m i n a t i o n s could be u n d e r t a k e n , a n d n i n e s u r v i v e d i n hospital long enough for some e x a m i n a t i o n s (skull X - r a y , CSF e x a m i n a t i o n , etc.) to be carried ont. According to the a u t o p s y findings s u b d u r a l h a e m a t o m a was the cause of death in 20 cases (83 ~ ). I n the other 4 the cause was b r a i n contusion (3 eases) a n d alcohol i n t o x i c a t i o n (one ease). I n 4 6 % of the a u t o p s y cases there was no k n o w n eraniocerebral t r a u m a , a n d i n the others there h a d been t r a u m a 4 to 46 days before d e a t h (median 18 days). A short i n t e r v a l was often associated with t r a u m a which m a y have been secondary to a pre-existing h a e m a t o m a . A m o n g the neurosurgically t r e a t e d cases 25 ~ h a d no history of t r a u m a .

Epidemiology of Chronic Subdural Haematoma

249

Using these cases as basis for calculation of incidence the following figures were obtained. On December 31, 1969 the City of ttelsinki had 533,214 inhabitants. The incidence during the study period was thus 1.72/lO0,O00/year. In the various age groups the incidences per 100,000/ year, calculated on the basis of the above census, were as shown in Table 2. As is evident the incidence was higher for men than for women, and the incidence increased steeply in older age groups. Table 2. Age-Speci/ic Incidence o/ Chronic Subdural Haematoma in Helsinki During 1967-73 (cases/lOO,OOO/year) Age groups, years Sex 20-29

30 39

40-49

50-59

60-69

70-79

80-

Men Women

0.25

1.56 0.76

4.0 1.2

9.1 0.8

8.4 1.8

15.7 4.2

-7.8

All

0.13

1.15

2.5

4.2

4.2

7.4

6.4

In more than half the patients there was a history of chronic alcoholism. The patients were classified according to occupation in social classes I - - I V . 11.9~ of the Helsinki populatiotl are in class IV, but in this study 26.6~/o of the cases were from this social class.

Discussion The incidence of 1.72/100,000/year must be considered to represent the great majority, although not all, of the cases of chronic subdural haematoma in the Helsinki population. There are two possible ways in which eases may escape detection. Firstly, autopsies are not invariably performed on all patients dying in Helsinki, and secondly, the Department of Forensic Medicine does not perform all the autopsies on cases of subdural haematoma. There are four other autopsy departments serving the City of Helsinki. These departments are obliged to interrupt an autopsy if a subdural haematoma is found and send the body to the Department of Forensic Medicine. We have contacted the pathologists of these four autopsy departments and have been informed that during the years in question there have been only a few exceptional eases which were not transferred to the Department of Forensic Medicine after detection of a haematoma in the subdural space. I n the present study we think that the most important source of error has been the great number of aged persons, some of whom may have harboured chronic subdural haematomas but who have been

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R. Fogelholm et al. : Epidemiology of Chronic Subdural I-Iaematoma

diagnosed as having senile dementia or "cerebral arteriosclerosis" (Perlmutter 1961, l~askind et al. 1972) and have not been submitted to autopsy. The incidence of chronic subdural haematoma increases steeply with advancing age. Although a chronic haematoma is often associated with craniocerebral trauma, a significant number of patients give little or no history of injury. This, in addition to the often vague symptoms, is perhaps one of the circumstances that confuse the clinician and may prevent correct diagnosis during life. I t was also evident from the present study that a history of craniocerebral trauma was less frequent in the autopsy cases (54%) than in the surgically treated ones (75%). The possibility that information available in the autopsy cases was incomplete may, however, partly account for this difference. Applied to the whole Finnish population the incidence of 1.72/ 100,000/year gives about 75 cases per year. From the Helsinki findings we conclude that one third of these will die with undiagnosed chronic subdural haematomas. This state of affairs and the possibility of surgical cure of chronic subdural haematoma underlines the importance of early diagnosis. Acknowledgements The authors wish to thank Professor Kauno Laiho for permitting us peruse the autopsy files of the Department of Forensic Medicine. References Eehlin, F. A., S. V. 1%. Sordillo, and T. Q. Garvey Jr., Acute, subacute, and chronic subdural hematoma. J. Amer. mad. Ass. 161 (1956), 1345--1350. Klug, W., F. Loew, and S. Wfistner, Zur Frage der H~ufigkeit ehroniseher subduraler l-I/~matome naeh Seh~delverletzungen. Zentralbl. Neurochir. 21 (1961), 51--56. Perlmutter, I., Subdural hematorna in older patients. J. Amer. mad. Ass. 176 (1961), 212--214. Raskind, R., M. B. Glover, and S. R. Weiss, Chronic subdural hemaboma in the elderly: A challence in diagnosis and treatment. J. Amer. geriatr. Soc. 20 (1972), 330--334. Weber, G., ])as chronisehe Subduralh/~matom. Schweiz. reed. Wschr. 99 (1969), 1483--1488.

Authors' addresses: R. Fogelhohn, M.D., Department of Neurology, University of tIelsinki, I-Iaartmaninkatu 4, SF-00290 Helsinki 29, Finland, O. Waltimo, M.D., Department of Neurology, University of IIelsinki, ttaartmaninkatu 4, SF-00290 I-Ielsinki 29, Finland.

Epidemiology of chronic subdural haematoma.

During the seven year period 1967-1973 a total of 64 residents of the City of Helsinki were diangosed as having chronic subdural haematomas. Forty of ...
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