An extensive review of the literature showed
that a considerable amount of study has been devoted
to pneumonia in the earliest days of life, but that
no unanimity of opinion has been reached with regard
to its usual mode of production; that relatively
little attention has been paid to the types and
causes of pneumonia occurring later in the neonatal
period; and that knowledge of the bacteriology of all
types of neonatal pneumonia is very incomplete.
The present investigation was based on a series
of 541 necropsies performed on stillborn foetuses
and liveborn infants who survived not more than 28
days.
Among these there were 177 cases (32.7 per
cent) with acute inflammatory changes in the lungs.
In 174 cases pneumonia was present; in 3 only the
bronchi were inflamed.
The facts relative to sex, age and seasonal
incidence in this series are given.
In the pathological study the cases are divide
according to their principal pathological characters
into four groups:- (1) pneumonia associated with aspiration
of contents of the amniotic sac or vagina;
(2) pneumonia associated with other pulmonary conditions
caused by stress of birth or otherwise peculiar
to the newborn; (3) bronchopneumonia and allied types
(postnatal respiratory infections); and (4) septicaemia
with secondary (haematogenous) involvement of
the lungs.
The pathological features of each type are
described; relevant facts from the clinical and material history, and the results of bacteriological examination
are recorded; and an attempt is made to deter
mine the probable method and time of infection, wheth
er before or after birth.
It 'is, shown that congenital pneumonia certainly occurs, but proof of bacterial infection received
before birth is often not obtainable. It cannot be
assumed that all cases associated with aspiration of
liquor amnii are examples of prenatal bacterial infection.
Other possible explanations of these cases
are discussed.
Congestion, oedema, atelectasis and haemorrhage
resulting from stress of birth or otherwise, are of
great importance as conditions predisposing to pneumonia
in the early days of life.
Among postnatal respiratory tract infections
the principal types are typical bronchopneumonia, due
to various bacteria, and special forms caused by
staphylococcal and pneumococcal infection.
Staphylococcal infection produces a type of
pneumonia with distinctive characters, leading to
widespread suppuration.
Pneumococcal infection, when pure, often produces
a special type of pneumonia, which has some
features resembling lobar pneumonia but differs in
the extent and distribution of the consolidation.
The term 'alveolar pneumonia' is suggested for this
type.
Metastatic lesions in the lungs resulting from
septicaemia take various forms, of which a description
is given. A form that is apparently peculiar to
young infants is described: a septic pleurisy followe
by lymphogenous invasion of the lungs by the inflammatory
process. An anatomical explanation of the oc-
currence of this process only in very young subjects
is offered.
In this series of cases pleurisy occurred with
septicaemia and when pulmonary suppuration was present,
but not otherwise.
The relation between age and pathological type
of pneumonia is discussed.
In the bacteriological study the results of
examination of 150 cases are presented.
The relation of the bacteriology to the pathological
type of pneumonia and to the age at death is
discussed.
An account is given of each of the types of
bacteria concerned, as regards its frequency, pathogenic action and other relevant matters.
Tree prominent part played by organisms of the
colon bacillus group is noted. They were of frequent
occurrence in cases of postnatal infection, as well
as in those due to infection received before or during
birth. The precautions taken to avoid the fallacy
of postmortem and terminal invasion by these
organisms are described.
Observations on the bacterial flora of the
mouth and throat of the newborn are recorded, and an
account is given of previously published work on
this subject.
It is concluded from this study that bacteria
derived from the environment after birth are in general
more important than bacteria aspirated during .
birth.
In view of the evidence of special susceptibility
in the newborn to colon bacillus infections,
series of agglutination tests was carried out, in
order to determine whether susceptibility could be
explained by an absence of antibodies for these organisms
in their blood serum.
It was found that agglutinins for organisms of
the Bact. coli group were often present in low concentration
in the blood serum of the newborn, and occasionally
in higher concentration, depending upon
the amount of agglutinin in the blood serum of the
mother.
The inconsistent results obtained with different
strains of the colon bacillus. group cyst doubt
upon the efficacy of protection conferred by agglutinins
against these organisms.
In the general discussion the importance of
the preventive approach to the problem of neonatal
pneumonia is emphasised.
The intimate connection between complications
of labour and those types of pneumonia that prevail
in the earliest days of life is indicated.
The causes and effeots of atelectasis in relation
to neonatal pneumonia are discussed.
In connection with pneumonia due to primary
respiratory tract infection after birth, the significance
of colon bacillus infections is discussed. The
frequency of pneumonia due to these organisms is believed
to indicate a special susceptibility in the
newborn.
Further evidence of this susceptibility is
found with reference to septicaemia and meningitis
in the newborn.
A similar susceptibility is manifested towards
other common organisms, notably staphylococci.
Possible explanations of this susceptibility
are discussed.
In view of the special susceptibility of tile
newborn to infection with common organisms that occur
as commensals in older persons, the environmental
conditions of newborn babies and the practice of neonatal
hygiene of the highest possible standard are
vitally important.
The truth of this contention is illustrated by
a comparison of the incidence of neonatal pneumonia
in two hospitals.
The conclusion is reached that neonatal pneumonia is to a great extent preventable. The prevention
of those types that are prevalent in the earliest days
is an obstetrical problem and would be in large measure
achieved by the avoidance of severe foetal asphyx-
ia. Cases due to postnatal infection can be prevented
by strict attention to hygienic principles.
