LOCAL SPREAD OF MASTOID INFECTIONS
This may occur in an acute or chronic form in a pneumatized or diploeic
petrous bone, and is due to direct extension of infection from the middle
ear or mastoid. It may occur before operation or as a postoperative compli-
cation, usually 2 or 3 weeks, but occasionally several months, later.
PATHOLOGY. The pathology is essentially that of the mastoid infection
which precedes it. Infection may be confined to the petrous bone, or it may
extend intracranially and result in a localized meningitis or an extradural
abscess in the middle or posterior fossa. Spread may also occur downwards
and cause abscess formation in the pharynx. Occasionally a spontaneous
drainage through the middle ear may result in recovery.
CLINICAL FEATURES. There is severe unilateral headache, spasmodic in
type and usually retro-orbital, supra-orbital or temporal in distribution,
due to irritation of the related nerves. In the presence of otitis media, such
headache with diplopia due to paralysis of the abducens nerve (Gradenigo's
syndrome) is almost diagnostic of the condition. A slight rise of temperature
may accompany the onset of the headache. Following mastoidectomy a
sudden recurrence or increase of discharge, often with pulsation, suggests
a petrositis. Other transient features may occur, such as facial palsy and
vertigo with vestibular nystagmus due to labyrinthine irritation. Lumbar
puncture should be performed. The cerebrospinal fluid may be under slightly
increased pressure, but is otherwise normal. Any departure from normality,
such as a slight increase in cells, is an indication for early surgical explora-
tion. Disappearance of symptoms may indicate resolution, but if this is of
sudden onset it may signify intracranial rupture and the development of
meningitis or extradural abscess.
DIAGNOSIS. Diagnosis is made from: (i) persistent otorrhoea following
cortical mastoidectomy; (ii) positive findings on radiography of the petrous
bones (Fig. 173, C, p, 336); and (iii) the discovery of a fistulous track leading
to the petrous apex on revision of the operation.
TREATMENT. In the early acute stages treatment is that of the associated
otitis media and mastoiditis, and includes vigorous antibiotic therapy with
the appropriate drug after sensitivity tests have been carried out. The pain
may be sufficiently severe to require morphine. As a rule mastoidectomy is
indicated and a search must be made for the presence of a fistula leading
to the petrosal apex, and, when found, it must be curetted to facilitate
drainage. When the condition is chronic, or when it becomes manifest after
the failure to obtain a cure with a simple cortical mastoid operation, the
radical type of operation may be required.