DOI: 10.1002/ ms3.957
ORIGINAL ARTICLE
Oesophageal pneuma osis: compu ed omog aphic
cha ac e is ics in h ee dogs (2018–2021)
Ma c O s-Po ca 1Alejand o O o bia1Ca oline Fina1
Vicen e José He e ía-Bus illo2Noemi Gómez-Ma ín2
José Daniel Ba ei o-Vázquez3Sonia González-Rellán4Ca lo Anselmi1
1P ide Ve e ina y Cen e, De by, De byshi e,
UK
2Hospi al Ve e ina io Uni e sidad Ca ólica de
Valencia, Valencia, Comunidad Valenciana,
Spain
3Hospi al Ve e ina io Uni e si a io Ro
Codina, Facul ade de Ve e ina ia,
Uni e sidade de San iago de Compos ela,
Lugo, Galicia, Spain
4Depa amen o de Ana omía, P odución
Animal e Ciencias Clínicas Ve e ina ias,
Facul ade de Ve e ina ia, Uni e sidade de
San iago de Compos ela, Lugo, Galicia, Spain
Co espondence
Ma c O s-Po ca , P ide Ve e ina y Cen e,
De by, De byshi e DE24 8HX, UK.
Email: [email p o ec ed]
Abs ac
Backg ound: Oesophageal pneuma osis (OP) is de ined as he p esence o gas wi hin
he oesophageal wall. The desc ip ion o his condi ion in e e ina y medicine is cu -
en ly lacking. The pa hogenesis o alimen a y ac pneuma osis emains unclea .
Cu en li e a u e desc ibes ha access o gas in o he oesophageal wall may occu by
one o a combina ion o he ollowing mechanisms: mucosal dis up ion, inc eased in a
o ex a-luminal p essu e o dissec ion o gas om an ex a-oesophageal sou ce.
Objec i es: The aim o his mul i-cen ic case se ies was o desc ibe he compu ed
omog aphy (CT) indings o OP in dogs.
Me hods: Th ee adul dogs we e included. One dog p esen ed wi h gas oin es inal
signs and gene al malaise while he o he wo p esen ed wi h spon aneous acial and
ce ical subcu aneous emphysema.
Resul s: CT e ealed di e en deg ees o in amu al gas along he oesophageal wall
in all cases. The i s dog was diagnosed wi h emphysema ous gas i is based on he
p esence o gas ic pneuma osis pai ed wi h compa ible clinicopa hological and endo-
scopic indings. This dog was success ully ea ed wi h an ibio ics. The emaining wo
dogs we e diagnosed wi h spon aneous pneumomedias inum and equi ed no su gical
o medical ea men .
Conclusions: In all cases wi h OP, he e was concu en gas ic pneuma osis.
Gas ex ensi ely and ci cum e en ially dis ibu ed wi h a banded shape along he
oesophageal wall was p esen in pa ien s wi h p esumed mu al gas dissec ion because
o pneumomedias inum. Con e sely, a ocal and mild amoun o mu al gas wi h a ubu-
la shape was iden i ied in he dis al segmen o he oesophagus in he pa ien wi h
emphysema ous gas i is.
KEYWORDS
alimen a y ac pneuma osis, canine oesophagus, in amu al oesophageal gas, oesophageal wall
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© 2022 The Au ho s. Ve e ina y Medicine and Science published by John Wiley & Sons L d.
2382 wileyonlinelib a y.com/jou nal/ ms3 Ve Med Sci. 2022;8:2382–2389.
PORCAR ET AL.2383
1INTRODUCTION
Oesophageal pneuma osis (OP) is he e m used o desc ibe he p es-
ence o gas wi hin he oesophageal wall (S udde & Gay, 2012).
In human medicine OP is a ely desc ibed and may be idiopa hic
o seconda y o a speci ic unde lying condi ion (Neal & Jha, 2020).
Pneuma osis o he alimen a y ac can occu om he oesopha-
gus o ec um seconda y o a wide spec um o condi ions. Benign
condi ions include immune-media ed, in ec ious, pulmona y, gas oin-
es inal, ia ogenic and idiopa hic diseases. I has been desc ibed also
wi h li e- h ea ening condi ions such as auma ic, mechanical and
ischemic p ocesses (As e e al., 2005; Bakkali e al., 2014; Chelimilla
&Makke ,2013; Fisk & Allen-Du ance, 2019; G assi e al., 1995;
Ho e al., 2007, Fische i e al., 2004; Keklik e al., 2016; Lang e al.,
2011; Le o , 2008; Mi suyoshi e al., 2015; Tewa i e al., 2017;Tixe-
do e al., 1998; To es e al., 2018). These wo g oups o condi ions
ha e di e en clinical managemen and p ognosis, bu hey can ha e
simila imaging indings. The e o e, dis inguishing be ween hese con-
di ions is clinically ele an , bu emains a challenge o he adiologis
in daily p ac ice. Published li e a u e desc ibes ha gas access in o he
oesophageal wall may occu due o one o a combina ion o he ollow-
ing mechanisms: inc eased in aluminal p essu e, mucosal dis up ion,
and/o dissec ion o gas om an ex a-oesophageal sou ce (Neal & Jha,
2020).
Diagnos ic imaging is essen ial o he diagnosis o OP, wi h com-
pu ed omog aphy (CT) being he gold s anda d in human medicine
due o i s high sensi i i y e alua ing he oesophageal wall compa ed
o o he imaging modali ies (Neal & Jha, 2020). In humans, alimen a y
ac pneuma osis may cou se wi h gas oin es inal signs, al hough
some pa ien s emain asymp oma ic (Ho e al., 2007). CT indings o
OP may a y depending on he amoun o in amu al gas as well as
he unde lying ae iology. The gas wi hin he oesophageal wall is usually
seen as mul i- ocal in amu al gas collec ions wi h a linea o banded
shape dis ibu ed ci cum e en ially. When a la ge amoun o in a-
mu al gas is de ec ed, i may comple ely su ound he oesophageal
mucosa p oducing an ‘ai donu ’ sign (Neal & Jha, 2020). Pa ial o com-
ple e collapse o he hin oesophageal mucosa seconda y o in amu al
expansion has also been desc ibed in humans, esul ing in di e en
geome ic mucosal shapes (Neal & Jha, 2020).
A he ime o his s udy, acco ding o ou e iew o li e a u e, he e
a e no published pee - e iew epo s desc ibing OP and i s imaging
cha ac e is ics in e e ina y pa ien s. The main objec i e o he cu en
s udy is o desc ibe he clinical and CT cha ac e is ics in a g oup o dogs
wi h OP.
2METHODS
This was a mul i-cen ic, e ospec i e, case se ies s udy design. The
da abases o h ee e e ina y hospi als we e e iewed: ‘P ide Ve e i-
na y Cen e’ (PVC; De by, UK), ‘Hospi al Ve e ina io de la Uni e sidad
Ca ólica de Valencia’ (HV-UCV; Valencia, Spain) and ‘Hospi al Ve -
e ina i Canis Gi ona’ (HVCG; Gi ona, Spain). The da abases we e
sea ched o dogs wi h a adiologic diagnosis o OP and a CT s udy
pe o med du ing he diagnos ic wo k-up. The keywo ds used in he
adiology da abase and in he medical eco ds da abase o he h ee
hospi als we e ‘oesophageal pneuma osis’, ‘in amu al oesophageal
gas’ o ‘gas wi hin he oesophageal wall’. Pe mission o use clinical and
diagnos ic imaging da a o esea ch was p o ided h ough in o med
consen om he owne s a he ime o admission.
Inclusion c i e ia o he p esen s udy we e as ollows: canine cases
wi h CT images o diagnos ic quali y, a ailable endoscopy, his ology
esul s o , o he wise, esolu ion o OP on subsequen imaging examina-
ion, comple e pa ien his o y and a ailable haema ological and se um
biochemical analyses. All decisions ega ding inclusion o exclusion
we e made based on a consensus o he i s au ho ( i s -yea small
animal imaging esiden ; MOP Eu opean College o Ve e ina y Diag-
nos ic Imaging [ECVDI]) and a boa d-ce i ied e e ina y adiologis
(CA Eu opean College o Ve e ina y Diagnos ic Imaging [ECVDI]).
Reco ding and analysis o medical da a we e supe ised by wo
specialis boa d-ce i ied e e ina y adiologis s (CF and CA, Eu o-
pean College o Ve e ina y Diagnos ic Imaging [ECVDI]), a special-
is double boa d-ce i ied e e ina y in eme gency and c i ical ca e
(VJHB, Ame ican College o Ve e ina y Eme gency C i ical Ca e
[ACVECC] and Eu opean College o Ve e ina y Eme gency C i ical
Ca e [ECVECC]) and an expe ienced e e ina y adiologis (JDVB,
PhD). The ollowing in o ma ion was e ospec i ely e iewed, i a ail-
able, by he i s au ho (MOP), awa e o inal diagnosis and wo king
a he P ide Ve e ina y Cen e a he ime o da a eco ding: sig-
nalmen , anamnesis, clinical signs, physical examina ion, haema ology,
biochemis y, diagnos ic imaging (CT and ul asound) ea u es, endo-
scopic indings, his ological and bac e iological esul s, as well as he
ou come.
Abdominal B-mode ul asonog aphic examina ions (Gene al Elec-
ic LOGIQ S7, Seongnam, Ko ea) we e pe o med on ans e se and
sagi al planes using elec onic mic ocon ex (10C) and elec onic linea
(ML6-15) p obes, wi h equencies anging be ween 8 and 15 MHz.
The CT s udies o he head, neck, and ho ax (ex ending he ield o
iew app oxima ely up o he hi d lumba e eb a), we e pe o med
unde gene al anaes hesia in all dogs. Due o he mul i-cen ic cha ac-
e o he s udy, he s udies we e ob ained using wo di e en 16-slice
CT scanne s (Gene al Elec ic Medical Sys ems, B igh Speed, Chicago,
IL, USA and Siemens SOMATOM Scope, Siemens Heal hca e Diagnos-
ics, IL, USA) wi h wo pa ien s posi ioned in s e nal and one in do sal
ecumbency. Anaes he ic p o ocols a ied in each ins i u ion acco d-
ingly o he a ending clinician. Acquisi ion pa ame e s we e as ollows:
helical scan mode, 0.625–2.5 mm slice hickness, a pi ch o 0.8–1.75,
56–80 mAs ube cu en , 120–130 kV ube ol age, 512 ×512 ma ix,
and a so issue and bone econs uc ion algo i hm. Window wid h
and le el we e app op ia ely adjus ed and mul i-plana e o ma ing
was used whene e necessa y o op imal e alua ion. Fo all dogs, CT
images we e acqui ed p io o and a e 45 s ollowing adminis a ion
o iohexol a 600 mgI/kg. When a ailable, he con as was injec ed
a a a e o 2–3 ml/s ia a cephalic ca he e by an angiog aphic p es-
su e injec o (Nemo o Dual Sho Alpha 7, Tokyo, Japan). In one o he
cases an injec o was no a ailable, he e o e, con as injec ion was
manually pe o med and images we e acqui ed app oxima ely 45 s
ollowing bolus injec ion.
20531095, 2022, 6, Downloaded om h ps://onlinelib a y.wiley.com/doi/10.1002/ ms3.957 by Uni San iago Compos ela, Wiley Online Lib a y on [22/01/2025]. See he Te ms and Condi ions (h ps://onlinelib a y.wiley.com/ e ms-and-condi ions) on Wiley Online Lib a y o ules o use; OA a icles a e go e ned by he applicable C ea i e Commons License
2384 PORCAR ET AL.
CT s udies we e e iewed by wo ECVDI-ce i ied e e ina y adi-
ologis s (CF and CA), an expe ienced e e ina y adiologis (JDBV),
and wo i s -yea ECVDI esiden s (MOP and AO). All obse e s we e
awa e o he p esen ing clinical signs a he ime o in e p e a ion.
They we e no awa e o he endoscopic indings (p esence/absence o
mucosal wall lesions), inal pa ien ou come, o o he esul s (e.g. his-
ologic diagnosis). Disag eemen s we e esol ed h ough a consensus
eading by all e iewe s. CT s udies we e e iewed using an image anal-
ysis wo ks a ion and a comme cially a ailable open-sou ce DICOM
imaging iewing analysis so wa e (Ho os®, h ps://ho osp ojec .o g).
The ollowing CT cha ac e is ics we e eco ded based on a inal con-
sensus among he obse e s: loca ion, dis ibu ion and amoun o
in amu al gas along he included alimen a y ac ( he amoun was
classi ied subjec i ely as mild, mode a e o ma ked), oesophageal and
gas ic wall enhancemen , p esence o egional pe iphe al a s anding
pa e n, pneumope i oneum, pneumomedias inum o gas accumula ed
in he subcu aneous space o o he o gans/ ascula u e, p esence
o ca i a y ( ho acic-abdominal) e usion and lymphadenopa hy. The
loca ion o he in amu al gas along he alimen a y ac was de ined
as oesophageal and/o gas ic depending on he a ec ed o gans. The
adiological diagnosis o oesophageal and/o gas ic pneuma osis was
based on de ec ion o hese in amu al gas collec ions. Fa s anding,
as desc ibed in he li e a u e, was used as c i e ia o pe i oneal in lam-
ma ion and conside ed compa ible wi h pe i oni is, s ea i is, asculi is
o oedema (Tho n on e al., 2011). F ee subcu aneous, abdominal o
medias inal gas was conside ed as gas non-con ained in hollow iscus
o pa enchyma ous o gans and de ined as subcu aneous emphysema,
pneumope i oneum/pneumo e ope i oneum o pneumomedias inum
espec i ely. Mu al con as enhancemen was subjec i ely assessed
as ei he no mal o absen . Lymphadenopa hy was assessed compa -
ing he a ailable li e a u e da a on canine lymph node measu emen s
(Beuke s e al., 2013; Iwasaki e al., 2016; Milo ance e al., 2017;
S ehlík e al., 2020; Teodo i e al., 2021). Addi ional CT indings we e
also eco ded when conside ed ele an by he au ho s (e.g. pulmona y,
hepa ic o ascula abno mali ies).
The e e ing e e ina y su geons we e con ac ed o he clinical
eco ds pos -diagnosis o he pa ien s. The ollow-up du a ion and ou -
come da a we e e ie ed om he clinical no es p o ided by he e e -
ing p ac ices. Ou come was classi ied as ‘de e io a ion’ in pa ien s
whe e examina ion e ealed clinical de e io a ion om he clinical
signs a p esen a ion, ‘no imp o emen ’ in pa ien s whe e examina ion
emained unchanged compa ed o p esen a ion, ‘imp o ing’ in pa ien s
demons a ing imp o emen wi h some emaining clinical signs, and
‘no mal’ o all pa ien s demons a ing an un ema kable examina ion
a he ime o e-examina ion.
3RESULTS
3.1 Clinical indings
Th ee dogs me he inclusion c i e ia, one om each ins i u ion. Pa ien
1 was a 4-yea -old in ac male Beagle, pa ien 2 a 6-yea -old emale
spayed Bo de Collie and pa ien 3, a 9-yea -old emale spayed Lhasa
Apso.
Pa ien 3 p esen ed wi h le ha gy, ano exia and neu ophilic leu-
cocy osis, as well as gas oin es inal signs including omi ing and
dia hoea. The o he wo pa ien s (1 and 2) did no p esen any
gas oin es inal signs no e idence o sys emic abno mali ies. Thei
p esen ing complain was acial and ce ical subcu aneous emphysema.
Physical examina ion was un ema kable on p esen a ion in bo h ani-
mals apa om he emphysema. Comple e blood coun s and se um
biochemis y p o iles we e no mal. No his o y o a auma o ecen
anaes he ic p ocedu e we e epo ed in any o he pa ien s.
3.2 Imaging indings
Reasons o imaging s udies we e ei he in es iga ion o he gas oin-
es inal signs (pa ien 3) o assessmen o a po en ial o igin o he
acial and ce ical subcu aneous emphysema (pa ien s 1 and 2).
Abdominal ul asound was pe o med only in pa ien 3. On he ini-
ial ul asonog aphic s udy, he gas ic wall was conside ed no mal.
Clinical de e io a ion o he pa ien leads o a second ul asonog aphic
examina ion p io o he CT s udy. Ma ked di use and i egula gas-
ic wall hickening wi h pa ial loss o he wall laye ing was de ec ed.
The e we e also mul iple in amu al gas collec ions along he wall and
ex ending o he a ea o he lowe oesophageal sphinc e , p oduc-
ing a ma ked e e be a ion a e ac . The e was nei he in aluminal
gas wi hin he in ahepa ic o ex ahepa ic po al ascula u e, no
p esence o pneumope i oneum.
CT s udies e ealed di e en deg ees o in amu al gas along he
oesophageal and gas ic wall in all dogs (Figu es 1–3). In he oesoph-
agus o pa ien s 1 and 2, he e we e mul i- ocal, ci cum e en ially
dis ibu ed collec ions o pa ie al gas wi h a banded shape (Figu e 2).
Con e sely, in pa ien 3, he e was a mild amoun o in amu al gas
seen as a ocal collec ion in he dis al segmen o he oesophagus wi h
a ubula shape (Figu e 3). In all dogs, he e was mode a e amoun o
gas p esen wi hin he gas ic wall. In amu al gas was no obse ed
in he es o he in es inal ac included in he ield o iew in any
pa ien . The oesophageal and gas ic mu al enhancemen was consid-
e ed wi hin no mal limi s in all dogs. Mode a e o ma ked acial and
ce ical emphysema (Figu e 4) and pneumomedias inum (Figu e 5)was
p esen in pa ien s 1 and 2 as well as mild pneumope i oneum. Mild
pneumo e ope i oneum was seen only in pa ien 2. S eaky pe i oneal
a ( a s anding pa e n) was seen only in pa ien 3. The ascula-
u e (including ho acic, mesen e ic and po al essels) was conside ed
wi hin no mal limi s in all dogs. Addi ional ele an indings we e a mil-
lime ic pleu al bleb in pa ien 1 and mild amoun o bila e al pleu al
e usion in pa ien 3. No o he ele an indings we e seen in pa ien 2.
No e iden lymphadenopa hy was de ec ed in any o he pa ien s.
3.3 Endoscopy, his ology and bac e iology
Oesophagogas oscopy and acheob onchoscopy we e pe o med in
pa ien 1 a e he CT s udy. Bo h we e conside ed un ema kable.
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PORCAR ET AL.2385
FIGURE 1 Pos -con as CT s udy wi h co esponding schema ic and labelled images o a pa ien wi h oesophageal pneuma osis and
concu en pneumomedias inum and subcu aneous emphysema. Sagi al plane (a and d), do sal plane (b and e) and ans e se plane (c and ). The
wall o he oesophagus is enclosed by he do ed lines (d, e and ). No e he p esence o ex ensi e amoun o in amu al oesophageal gas
ci cum e en ially dis ibu ed wi h a banded shape. In he ans e se images (c and ) he gas is su ounding he oesophageal mucosa p oducing an
‘ai donu ’ sign. Window wid h and le el we e acco dingly adjus ed o op imal e alua ion. Medium equency algo i hm o so issue window
wi h window le el =–185 HU and window wid h =1117 HU.
FIGURE 2 T ans e se pos -con as CT images, a he le el o C2–C3, o wo di e en pa ien s wi h oesophageal pneuma osis and concu en
subcu aneous (a) and ascial ce ical (a and b) emphysema. The whi e a ow is poin ing he gas in he oesophageal lumen. The a ow head is
poin ing he in amu al oesophageal gas ci cum e en ially dis ibu ed wi h a banded shape. Window wid h and le el we e acco dingly adjus ed o
op imal e alua ion. Medium equency algo i hm o so issue window wi h window le el =–185 HU and window wid h =1117 HU.
Pa ien 3 also had an oesophagogas oscopy a e he CT s udy. I
e ealed supe icial ulce a ions and se e e mul i- ocal hype aemic
lesions a ec ing he en i e gas ic mucosal su ace. The oesophagus
was un ema kable. Endoscopic biopsies o he gas ic mucosa we e
pe o med, and samples we e submi ed o his opa hology and bac-
e ial cul u e. His opa hology o he s omach e ealed an oedema ous,
haemo hagic and ib o ic mucosa, wi h inc eased clea spaces, ep e-
sen ing ai pocke s embedded wi hin he connec i e issue. Sca e ed
in aepi helial lymphocy es and plasma cells we e seen h oughou
he supe icial lamina p op ia. Mul iple spi al-shaped bac e ia we e
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2386 PORCAR ET AL.
FIGURE 3 Pos -con as CT images o a pa ien wi h oesophageal pneuma osis and concu en emphysema ous gas i is. Sagi al plane (a),
do sal plane (b) and ans e se plane (c). The whi e a ow is poin ing he gas in he oesophageal lumen. The e is a small amoun o oesophageal
in amu al gas poin ed by he a ow head wi h a ubula appea ance. In he do sal image (b) he dashed a ow is poin ing he in amu al gas ic gas.
Medium equency algo i hm o so issue window wi h window le el =40 HU and window wid h =350 HU.
FIGURE 4 T ans e se p e-con as CT images o a pa ien wi h acial (a) and ce ical (b) subcu aneous emphysema. The whi e a ows a e
poin ing he ma ked amoun o gas accumula ed and sca e ed h oughou he subcu aneous issue. High- equency algo i hm o bone window
wi h window le el =110 HU and window wid h =1946 HU.
FIGURE 5 T ans e se pos -con as CT images a he le el o he c anial medias inal e lec ion o wo di e en pa ien s wi h
pneumomedias inum. The whi e a ows a e poin ing he ma ked amoun o gas p esen in he medias inum su ounding he medias inal o gans
and s uc u es. High- equency algo i hm o lung window wi h window le el =–500 HU and window wid h =1400 HU.
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PORCAR ET AL.2387
isualised along he mucosal su ace. No e idence o mucosal nec osis
was iden i ied. Cul u e o he gas ic wall isola ed E. coli,P o eus sp.and
En e ococcus sp. This pa ien was diagnosed wi h emphysema ous gas-
i is based on he p esence o gas ic in amu al gas, sys emic abno -
mali ies and compa ible endoscopic and clinicopa hological indings.
3.4 T ea men and ou come
Pa ien 3 diagnosed wi h emphysema ous gas i is, imp o ed on an ibi-
o ic he apy. Clinical imp o emen was achie ed a e 1 week wi h
ul asonog aphic esolu ion o he gas ic pneuma osis. Medical man-
agemen was con inued o a mon h and he e has been no elapse o
clinical signs o da e.
The dogs p esump i ely diagnosed wi h spon aneous pneumomedi-
as inum, oesophageal and gas ic emphysema (dogs 1 and 2) equi ed
no ea men . Close moni o ing, a es pe iod wi h es ic ed exe -
cise and he use o a ha ness a he han a colla du ing walking
we e ecommended o he owne s. Comple e esolu ion o pneumo-
medias inum, oesophageal and gas ic pneuma osis was con i med on
a ollow-up CT s udy 1 mon h a e p esen a ion in bo h pa ien s.
The ea e , all pa ien s we e ollowed a hei espec i ely e e ing
e e ina y cen es wi hou ecu ence o signs ela ed o alimen a y
ac pneuma osis. No elapse o he p esen ing clinical signs has been
epo ed o da e.
4DISCUSSION
The p esen s udy desc ibes he clinical and imaging indings in h ee
adul dogs wi h in amu al oesophageal gas. Acco ding o he li e a u e
e iewed du ing he p esen s udy, hese a e he i s cases o canine
OP epo ed so a , wi h he i s desc ip ion o i s CT ea u es.
The pa hogenesis o alimen a y ac pneuma osis emains unclea .
In human medicine, wo main heo ies a emp o explain i s ae iology
p oposing an in ec ious o mechanical o igin (Mi suyoshi e al., 2015).
Alimen a y ac pneuma osis may occu due o bac e ial in il a ion o
he mucosa leading in amu al gas p oduc ion, o seconda y o mu al
gas dissec ion as a esul o inc eased in a- o ex a-luminal p es-
su e. The bac e ial model is suppo ed by he p esence o hyd ogen
gas in he in es inal wall, an indica o o anae obic bac e ial ac i -
i y, and by he high concen a ions o i in he exhaled ai o pa ien s
wi h in es inal pneuma osis (Togawa e al., 2004). The mechanical he-
o y p oposes wo pa hways o gas o en e he alimen a y ac . One
mechanism e e s o a ela i ely in ac mucosa due o inc eased in a-
and/o ex a-luminal p essu e (e.g. blun auma, omi ing o p esence
o gas in he medias inum/pe i oneum). The o he p ocess e e s o
an inc eased mucosal pe meabili y due o a di ec mucosal inju y (e.g.
ischemia, in lamma ion) and/o a de ec i e in es inal immune ba ie
(e.g. immunode iciency, immunosupp ession) (S Pe e e al., 2003).
OP is a a e condi ion in people and only a small numbe o cases
ha e been epo ed, al hough i is hypo hesised o be unde epo ed
(Neal & Jha, 2020). Cu en li e a u e desc ibes ha gas en e ing he
oesophageal wall may occu by one o a combina ion o he ollow-
ing mechanisms: mucosal dis up ion, inc eased in aluminal p essu e
o dissec ion o gas om an ex a-oesophageal sou ce. OP seconda y
o mucosal dis up ion has been desc ibed in auma ic inju ies asso-
cia ed wi h oesophageal in uba ion (Neal & Jha, 2020). Oesophagi is
o in lamma o y o in ec ious o igin could also lead o mucosal dis up-
ion allowing he gas o access he oesophageal wall (Li e al., 2018;
Muhammad e al., 2017; Vi a ka e al., 2019). Inc eased in aluminal
p essu e could lead he gas o en e he oesophageal wall h ough small
de ec s in he mucosa, eaching he submucosa o e en he muscula
laye . Documen ed cases desc ibe his p ocess du ing endoscopy o
seconda y o an obs uc ion o he alimen a y ac (Huang e al., 2015;
Ka z e al., 1972; Tewa i e al., 2017). Dissec ion o gas om an ex a-
oesophageal sou ce can occu in case o pneumomedias inum (Neal &
Jha, 2020). When gas en e s he medias inum, whe he om he lung
(Macklin e ec ), e ope i oneum o acial planes o he neck, i could
heo e ically en e in o he oesophageal wall h ough small de elop-
men al o acqui ed de ec s (Maunde e al., 1984;Neal&Jha,2020).
In addi ion, gas ic o in es inal pneuma osis, o en associa ed wi h
ischemic p ocesses, can di ec ly ex end in o he oesophageal wall (Lin
e al., 2015; Mi suyoshi e al., 2015;Neal&Jha,2020; Pasquali e al.,
2017).
In ou case se ies no his o y o a auma, choking o ecen anaes-
hesia was epo ed in any o he pa ien s. The e o e, he possibili y
o inc eased in aluminal p essu e was uled ou in all pa ien s. Addi-
ionally, in hose whe e oesophagoscopy was pe o med a e he CT
s udy, he oesophageal mucosa was no mal, hus a mac oscopic p i-
ma y oesophageal- ela ed disease was unlikely. In pa ien s 1 and 2,
he gas ic mucosa was un ema kable, bu he e was enough amoun
o pneumomedias inum po en ially igge ing he dissec ion o gas
h ough he oesophageal wall acco ding o he mechanical heo y. In
pa ien 3, he de ec ed gas ic al e a ions could po en ially lead o gas-
ic pneuma osis wi h seconda y gas dissec ion om he gas ic o he
oesophageal wall, acco ding o he p e ious published da a in humans
(Lin e al., 2015; Mi suyoshi e al., 2015;Neal&Jha,2020; Pasquali
e al., 2017). In pa ien s 1 and 2, he cause o pneumomedias inum was
no iden i ied by CT o endoscopy and he e o e conside ed idiopa hic.
The lumen o he achea and b onchi was endoscopically isualised,
along wi h he diges i e ac om he o al ca i y o he gas ic lumen,
wi hou de ec ing lesions ha jus i ied he al e a ions seen in he CT.
Acco ding o human li e a u e, oesophageal in amu al gas is usu-
ally no de ec ed on su ey adiog aphic o luo oscopic s udies, e en
e ospec i ely (Neal & Jha, 2020). The e o e, CT is he gold s anda d
imaging modali y o he de ec ion o gas in he oesophageal wall. I
also o e s addi ional ad an ages o e adiog aphy such as supe io
con as esolu ion wi hou supe imposi ion. In addi ion, CT may help
diagnose po en ial o igin o OP ha canno be iden i ied using adio-
g aphy alone. The au ho s ecommend he use o CT ins ead o o he
imaging modali ies o de ec ion o canine oesophageal pneuma osis.
Gas ic pneuma osis can be di ided in o wo sepa a e clinical
en i ies wi h simila imaging indings: emphysema ous gas i is and
gas ic emphysema. Emphysema ous gas i is is a li e- h ea ening
condi ion and gas ic emphysema is a ela i ely benign en i y
20531095, 2022, 6, Downloaded om h ps://onlinelib a y.wiley.com/doi/10.1002/ ms3.957 by Uni San iago Compos ela, Wiley Online Lib a y on [22/01/2025]. See he Te ms and Condi ions (h ps://onlinelib a y.wiley.com/ e ms-and-condi ions) on Wiley Online Lib a y o ules o use; OA a icles a e go e ned by he applicable C ea i e Commons License
2388 PORCAR ET AL.
(Ma sushima e al., 2015). Di e en ia ing be ween hese wo en i ies
depends mo e on clinical signs a he han on imaging indings (Thie y
e al., 2019) and should be conside ed essen ial o he selec ion
o he app op ia e ea men , inc easing he chance o su i al o
a ec ed pa ien s. OP is also an imaging inding a he han a de ini i e
diagnosis. The e m ‘emphysema ous oesophagi is’ is documen ed in
he human medicine li e a u e (Li e al., 2018) bu a he ime o his
s udy, no published epo s desc ibing o using he e m ‘oesophageal
emphysema’ we e ound. Dis inguishing be ween emphysema ous
oesophagi is and oesophageal emphysema was beyond he scope o
his case se ies. Gi en he lack o an his opa hological analysis o he
oesophageal wall, bo h en i ies we e included unde he umb ella
e m OP.
In ou case se ies, he pa ien diagnosed wi h emphysema ous gas-
i is (pa ien 3) had gas oin es inal signs and concu en sys emic
clinical abno mali ies, whe eas pa ien s p esumably diagnosed wi h
gas ic emphysema (pa ien 1 and 2) do no ha e gas oin es inal signs
o e idence o sys emic abno mali ies. The obse ed gas ic pneuma o-
sis in hese wo cases esol ed p omp ly wi h no ea men . In human
medicine, conse a i e ea men is ecommended in cases o alimen-
a y ac pneuma osis whe e he e is no e idence o ischemia (e.g.
absence o ele a ed se um lac a e and no mal mu al enhancemen on
imaging) (Spek o e al., 2014; T eyaud e al., 2017). In pa ien s 1 and
2, he suppo i e ea men was he ea men o choice. Mos o he
al e a ions de ec ed by CT had esol ed apidly, indica ing a benign
condi ion wi h good a ou able p ognosis.
This is he i s case se ies documen ing he p esence o canine
OP. CT allowed cha ac e isa ion o lesions p e iously no epo ed
in e e ina y medicine. CT indings a e like hose epo ed in human
medicine. The e was di e en amoun o in amu al oesophageal gas
depending on he ae iology. Gas ex ensi ely and ci cum e en ially dis-
ibu ed wi h a banded shape along he oesophageal wall was p esen
in pa ien s wi h p esumed mu al gas dissec ion because o a pneumo-
medias inum (Figu es 1and 2). Con e sely, a ocal and mild amoun
o mu al gas wi h a ubula shape was iden i ied in he pa ien wi h
emphysema ous gas i is (Figu e 3).
The main limi a ion o he p esen s udy is he educed num-
be o cases. Fu he s udies including his opa hological analysis o
he oesophageal wall and compa ison o image indings a e wa -
an ed. None o he dogs in he p esen s udy died o we e sub-
jec ed o eu hanasia, and he e o e his opa hological analysis o he
oesophageal wall was no a ailable o any o he included cases.
In conclusion, he au ho s sugges ha he p esence o mode a e
o ma ked amoun o di usely dis ibu ed in amu al oesophageal gas
could be igge ed by inc eased ex a-luminal p essu e, such as in case
o pneumomedias inum, whe eas a mild ocal amoun could be ela ed
o di ec ex ension om an adjacen sou ce (e.g. ex ension o gas ic
pneuma osis). Imaging s udies can be ancilla y in he diagnosis and
uling ou concu en p ima y diseases. Fu he s udies wi h la ge
pa ien popula ions a e needed o be e cha ac e ise oesophageal
pneuma osis (OP), and o de e mine i his can be ac ually subdi ided
in emphysema ous oesophagi is and oesophageal emphysema as wo
sepa a e clinical en i ies.
AUTHOR CONTRIBUTIONS
Concep ualiza ion, Da a cu a ion, Fo mal analysis, In es iga ion, Me hodol-
ogy, P ojec adminis a ion, Resou ces, So wa e, Valida ion, Visualiza ion,
W i ing - o iginal d a , W i ing - e iew & edi ing:Ma cO sPo ca .
Valida ion, Visualiza ion, W i ing - e iew & edi ing: Alejand o O o bia.
Valida ion, Visualiza ion, W i ing - e iew & edi ing: Ca oline Fina. Valida-
ion, Visualiza ion, W i ing - e iew & edi ing: Vicen e J. He e ia-Bus illo.
Valida ion, Visualiza ion: Noemi Gomez Ma in. Valida ion, Visualiza ion:
Jose Daniel Ba ei o. Valida ion, Visualiza ion: Sonia Gonz ’lez-Rell ’n.
Da a cu a ion, Fo mal analysis, In es iga ion, Me hodology, P ojec admin-
is a ion, Resou ces, Supe ision, Valida ion, Visualiza ion, W i ing - e iew
& edi ing: Ca lo Anselmi.
ACKNOWLEDGEMENTS
The au ho s would like o hank IVC E idensia o he publica ion
suppo und used o publish his o iginal esea ch.
CONFLICT OF INTEREST
The au ho s decla e no con lic o in e es .
DATA AVAILABILITY STATEMENT
The da a ha suppo he indings o his s udy a e a ailable on he
eques om he co esponding au ho . The da a a e no publicly
a ailable due o p i acy o e hical es ic ions.
ETHICAL STATEMENT
As a e ospec i e case se ies, no e hical app o al was equi ed.
ORCID
Ma c O s-Po ca h ps://o cid.o g/0000-0002-0200-2646
Alejand o O o bia h ps://o cid.o g/0000-0001-7928-0276
Ca lo Anselmi h ps://o cid.o g/0000-0001-6894-310X
PEER REVIEW
The pee e iew his o y o his a icle is a ailable a h ps://publons.
com/publon/10.1002/ ms3.957.
PREVIOUS PRESENTATION OR PUBLICATION
DISCLOSURE
A po ion o his esea ch was p esen ed as an o al communica ion a
he 2021 EAVDI-BID Au umn mee ing.
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