Intracranial complications of otitis media and mastoiditis

Abstract

This study is based on the intracranial complications of otitis media as were found in 167 cases in a series of 10,000 autopsies. The available and applicable literature dealing with the incidence of the intracranial complications in general and in particular has been reviewed, and wherever possible correlated with the data from the authors' series. By accumulating a large number of cases it was hoped to avoid errors in conclusion, so likely in a smaller number of cases.

In European clinics where autopsies are performed in all cases, the lethality of otitis media is found to be about 0.25 percent, while the autopsy incidence of intracranial complications varies from 0.25 to 1.0 percent. In the authors' series, in which consent for autopsy was necessary, the autopsy incidence proved to be 1.67%. Leptomeningitis, while varying considerably in the incidence in the various series is found most frequently, occurring in about one-half of the cases. Thrombosis of the venous channels is next most frequent, occurring in about one-fourth of the cases, while abscess of the brain occurs in about one-fifth of the cases. Subdural abscess is rather variable in its incidence, but probably occurs in about 5 to 10 percent of deaths due to intracranial complications. In the authors' series the greatest numbers of intracranial complications were found in the first 10 years of life, while the lethality of the intracranial complications was greatest in the second, third and fourth decades.

Thrombosis of the venous channels and abscess of the brain are uncommon in the first decade of life, but are common during adolescence and adult life. Cerebellar abscess, contrary to general opinion, is not more rare than cerebral abscess in the first decade.

Because of the less favorable environmental factors, males are more often affected by intracranial complications than females. Because of the relative incidence of extradural abscess and leptomeningitis, which so frequently result from acute otitis media, intracranial complications occur more commonly from the acute than chronic infections of the ear. Thrombosis of the venous channels seems to occur in about equal numbers from acute and chronic otitis media. Brain abscess is much more apt to develop after chronic middle ear disease. While extradural abscess is the most benign of the intracranial complications, it may operate in the production of other complications which are lethal, – most commonly leptomeningitis, but at times abscess of the brain.

Of the solitary lesions found at autopsy, leptomeningitis occurs in 40 to 60 percent of the cases, thrombosis of the venous channels in from 30 to 40 percent and abscess of the brain in from 20 to 30 percent. Thrombosis of the venous channels is most frequently accompanied by leptomeningitis when other intracranial complications are present, although brain abscess is not an uncommon finding.

Of the lesions associated with leptomeningitis, thrombosis of the venous channels is again of most frequent occurrence and abscess of the brain is the next most frequent. Leptomeningitis is the most frequent complication also of abscess of the brain, due to the occurrence of so many instances of intraventricular rupture. Thrombosis of the venous channels is the next most common lesion. The ratio of cerebral to cerebellar abscesses as found in a large number of cases is about two to one.