JOURNni OF MILITARV PHnRMnCO-MEDICINt N°7-2014
EXPERIENCE ON DIAGNOSIS OF DESCENDING MEDIASTINAL INFECTION AT VIETDUC HOSPITAL
Nguyen Due Chinh' SUMMARY
Descending mediastinal infection (DMI) Is ram and serious infection with a high mortality rate, v^lch complicates fmm pharyngeal, odontogenic Infection or esophageal perforation. Eariy recognition and tmatment am essential In order to minimize morbidity and mortality. Evaluation with imaging diagnosis, especially with computed tomography Is necessary to confirm the diagnosis and to facilitate surgical planning. The most important CT findings in diagnosis of DMI are widened mediastinum, air-fluid level In mediastinum and neck subcutaneous crackling Estrera's criteria could be implementing for diagnosis of DMIs. We present one series of 17 petlents with diagnosis of DMI. Fmm this study we found that the pathology of DMIs in Vietnam Is commonly caused by esophageal pertoratlon and we recommend performing the ilbro- gastroendoscopy associated with CT-scan for purposes of both diagnosis and Intervention.
* Key wonJs: Descending mediastinal infection: Esophageal perfomtion.
INTRODUCTION
Descending mediastinal infection (DMI) is a rare infection. It can get a serious and life-threatening complication with a mortality rate as high as 50%. The patients could die due to serious infections resulting in the multiple organ failure or serious bleeding.
Careful clinical examination and radiological evaluation are of great value because they can help to indicate timely surgical intervention and medical management [ 3 , 4 , 5 ] .
The most common cause of DMI is an esophageal perforation due to the foreign bodies or iatrogenic injuries as well as Boerhaave's pathology. In addition, a retropharyngeal abscess is a common pathological condition that is caused by an acute Infection of the throat, dental abscess or a chronic Infection such as tuberculosis of cervical spine. The patients should in almost cases hie treated surgically on emergency in association with antibiotic
therapy and resuscitation. However, the diagnosis needs to be established as soon as the patient admitted to facilitate the treatment planning and to prevent the mortality [5, 6, 7],
We reviewed the patients with diagnosis of DMI treated at Vietduc Hospital recently In order to share experiences on its diagnosis which could help to manage DMI on time and to reduce the morbidity and the mortality.
MATERIAL AND METHODS A retrospective study of patients with DMI diagnosed and treated at Viet Due Hospital during two years of 2011 - 2012 was earned out. All the patient records and autopsy reports were reviewed. The patients with uncompleted medical records and patients died without the results of operated checking or autopsy examination had been excluded from this study.
* Vietduc Hospital
Con-esponding author: Nguyen Due Chinh ([email protected]) 120
JOURNRL Of MILITRRV PHRRMflCO-MCDICINC N'>7-2014
The information on patients collected included gender, age, medical history, clinical features, results of laboratory and X-ray examinations, management and outcomes
RESULTS
The study included 17 cases with diagnosis of DMI. There were 4 female patients and 13 male patients. The mean age was 54.6 + 6 7 years.
Table 1: Clinical features and X-ray findings.
NO 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17 AGE
37
27
24
75
35
64
45
51
51
71
59
26
26
47
65
51
41 GENDER
Male
Male
Female
Female
Male
Male
Male
Male
Male
Male
Female
Male
Female
Male
Male
Male
Male
CAUSES Ludwig's angina due to dental
abscess Esophageal perforation due to
chicken bone Esophageal perforation due to
chicken bone Esophageal perforation due to
chicken bone Iatrogenic esophageal
perforation Tonsillitis caused Ludwig's
angina Ludwig's angina due to abscess of cervical lymph node
Esophageal perforation due to chicken bone Esophageal perforation due to
chicken bone Esophageal perforation due to
chicken bone Esophageal perforation due to
chicken bone Esophageal perforation due to
chicken bone Retropharyngeal abscess
caused Ludwig's angina Esophageal perforation due to
cervical spine implant Esophageal perforation due to
chicken bone Ludwig's angina due to throat
abscess Ludwig's angina due to throat
abscess
X-RAY FINDINGS (CT-SCAN) Widened mediastinum, air-fluid level in
mediastinum, pleural effusion Air-fluid at cervical level, and widened
mediastinum Foreign body with widened mediastinum,
air-fluid level Foreign body, widened mediastinum, air- fluid level associated with pleural effusion
Widened mediastinum with air-fluid level
Widened mediastinum, air-fluid level in mediastinum, pleural effusion Air-fluid level In mediastinum, pleural
effusion Air-fluid level in both cervical and
mediastinal areas Air-fluid level in mediastinum, pleural
effusion Air-fluid level in mediastinum
Air-fluid level tn mediastinum, pleural effusion Air-fluid level in mediastinum, widened
medlasflnum AJr-fluid level in mediastinum
Atr-fluid level in mediastinum
Air-fluid level in mediastinum
Air-fluid level in cen/ical and mediastinal areas
Widened mediastinum and pleural effusion
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JOURNRl Of MIUTHRV PHRRMRCO-MCDICINC N°7-2014
* Some clinical symptoms:
Fever, odour breathing: 17 patients (100%); cervical swelling, inflammation:
15 patients (88.2%); subcutaneous aackling:
10 patients (58.8%); dyspnea and chest pain: 7 patients (41.2%).
Blood examinations: leukocytosis in 100% of cases and white blood cell counts above 10 G/L in 85.6% of cases.
The fibro-gastroendoscopy was perfomied on emergency for 9 cases, in which 5 cases were removed the foreign bodies.
All the patients were operated, but then three of them were released to die at home (accounted for 17.6% of all patients).
DISCUSSION
Since the first case of DMI was described by Pearse in 1939, It was considered as a severe infection of the connective tissue of the neck spreading downward and can develop into a highly lethal complication.
Almost the first cases reported were caused by retropharyngeal or dental abscess spreading downward to the neck, nameiy as Ludwig's angina. From the neck, the infection spreads downward to the mediastinum and develops the medlastinltis or mediastinal abscess.
However, to date, the common cause of DMI is an esophageal perforation due to foreign bodies or iatrogenic injuries.
Despite modern therapy, the DMI is still associated with a high mortality ranging from 14% to 50%. Several causes of this situation are: the excessive delay of time between the onset of the primary infection and the date of hospitalization, the extent and aggressiveness of the infection, the pre-existing clinical status of the patient and diagnosis delayed...[3, 4, 5, 6, 7],
In 1983 Estrera et al [4] had developed the criteria of diagnosis of DMIs as follows:
- Clinical manifestation of serious infections.
- Demonstration of characteristic Imaging features of mediastinitis.
- Documentation of necrotizing mediastinal infection at surgery or postmortem.
- Establishment of a relationship between the oropharyngeal infection and development of a necrotizing mediastinal process.
As above mentioned, the delayed diagnosis could cause the delay of proper treatment and result in the high morbidity and mortality. Early diagnosis can significantly help to reduce the mortality.
Lacking of knowledge and facilities, DMI has conferred a very poor prognosis.
Thus, we would like to discuss about the diagnosis of DMI as the criteria of Estrera.
1. Establishment of a relationship between the oropharyngeal infection and development of a necrotizing mediastinal process.
In the past, DMIs were commonly caused by oropharyngeal Infections. Nowadays the common cause is the esophageal perforation. Pearse et al. had collected one series of 110 cases of DMI and found that 64 cases (58,2%) related to an esophageal perforation, and 21 cases (19%) were caused by buccopharyngeal or dental atiscess. The esophageal perforation could be occurred due to foreign bodies as well as iatrogenic injuries. Some authors had reported the post-emetic rupture of the esophagus in the Boerhaave's syndrome [6, 7, 8],
The study of Nguyen Due Chinh et al [9] in 2001 had collected 56 cases of DMI.
There were 51 cases (91%) caused by esophageal perforation, and in all most of 122
JOURNRL Of MIUTRRV PHARMRCO-MCDICINC N°7-2014 these cases (92.2%), the perforation of
esophagus was due to the chicken bone ingestion.
In our study there were 9 cases (52.9%) of esophageal perforation due to chicken bones, 2 cases of esophageal perforation due to iatrogenic injuries dunng perfonning the esophageal fibro- endoscopy. Other 6 cases were caused by fauccalpharyngeal infections. In total, there were 11 cases of DMI caused by esophageal perforation (accounted for 64.7% of all patients). This result is similar to that of some other studies 11,8],
2. Clinical manifestation of serious infections
Clinical manifestation presents symptoms of the serious infections such as fever, chest pain, leukocytosis and high blood sedimentation rate. These symptoms are important clues to diagnosis of DMIs, especially in the patients with delay in hospitalization. Some other clinical symptoms of serious infection such as severe dyspnea, tachycardia, and high fever suggested septic shock at high risk of death noted.
Physical examination revealed local swelling or inflammation, cervical subcutaneous crackling and bad odour breathing [3, 7,8],
In our study, the clinical symptoms of serious Infections were also found in very high frequency: high fever and bad odor breathing in 100% of cases, neck swelling in 88.2%, subcutaneous crackling in 58.8%
and dyspnea in 42%. Laboratory investigations revealed leukocytosis in 100% of cases and white blood cell counts above 10 G/L in 85.6% of cases.
3. Characteristic imaging features of mediastinitis.
According to Dolikay Kilic et al [3], the DMI is a high lethal complication and
careful clinical examination as well as X- ray study based on the characteristic imaging features of mediastinitis could help to establish early diagnosis and to give proper interventions, which reduce the mortality. Imaging examinations being usually used in diagnosis of DMI are:
* Ultrasound; useful to get findings of neck tissues edema, air-fluid or abscess, subcutaneous air, foreign bodies or local pathology such as cancer, adenopathy.
However, this examination could only Investigate the upper part of cervical areas or neck, and it could not be useful when the infection spreading down to mediastinum.
Plain chest radiographs: easy to perform. However, it seems to be not able accurate diagnosis due to shortage of sensitivity as well as specificity. Conventional radiographs may demonstrate retropharyngeal soft tissue swelling, widening of mediastinal shadow, gas bubbles in the soft tissues of the neck, pneumomediastinum, and these findings could in turn prompt further evaluation by CT to confirm.
* Computed tomographic scanning: to visualize soft tissue and potential spaces in the neck and chest. CT imaging is typically obtained following IV administration of an iodine-based contrast. CT evidences of mediastinitis include localized mediastinal fluid collection or abscess, gas bubbles in the mediastinal soft tissues, pleural or pericardial effusion. It may be seen a diffuse mediastinitis characterized by increased density of the mediastinal fat with resultant loss of definition of normal fat planes. Mediastinal abscess is diagnosed based on the presence of a well-defined low-attenuation fluid collection with or without air, which may demonstrate rim 123
JOURNRl or MIUTRRV PHRRMRCO-MCDICINC N°7-iD14 enhancement following contrast administration.
In addition, to confirm a.diagnosis of DMI and to detect complications, CT assessment of the extent of infection would aid in detemiining optimal management and can assist in surgical planning and in assessing response to therapy [2, 11, 12].
In our study, all the patients (100%) were investigated by both plain chest radiographs and CT examination with contrast administration. These examinations had confirmed the diagnosis of DMI and helped to make the surgical planning as well.
Figure 1 Plain chest radiographs
Figure 2: Chest computed tomography.
* Flbro-gastroendoscopy: Nowadays as the common cause of DMI is esophageal perforation due to foreign bodies the fibro- gastroendoscopy on emergency could aid to accurate the esophageal lesion and to remove the foreign bodies as well. On the other hand, if the foreign bodies were suspected on imaging examination, the endoscopy could be performed to confimi diagnosis. We had performed the fibro- gastroendoscopy on emergency for 9 cases (52.9% of all patients), and no esophageal lesion was found only in one case.
Although this procedure vras not mentioned in the criteria of Estrera, it could be helpful in conflmiing the diagnosis of DMI because nowadays the common cause of DMI in Vietnam is esophageal perforation.
4. Documentation of necrotizing mediastinal infection at surgery or postmortem.
Although the surgical approaches associated with comprehensive care management have improved mortality, complications of DMI can still be severe.
The surgical Interventions could assess the lesions, confirm the diagnosis and manage the DMI [1, 2, 11], All 17 patients in our study had undergone the surgery on emergency and the DMIs were confirmed during operation.
CONCLUSION
Clinicians must' be aware if the possibility of a DMI in patients with a suspected esophageal perforation (due to foreign bodies as chicken bone or after endoscopy e.xamination) or a banal oropharyngeal abscess that is associated with persistent fever, neck swelling and 124
JOURNRL or MIUTRRV PHRRMflCO-MCDICINC N°7-20U pain. Clinically suspected DMI should be
evaluated and checked carefully with the imaging examinations, especially CT-scan with contrast administration, it could help to establish the diagnosis and to make treatment planning.
Estrera's criteria could be implementing for diagnosis of DMI. In Vietnam, due to the pathology of DMi is commonly caused by esophageal perforation, we recommend to perfomi the fibro-gastroendoscopy for purposes of both diagnosis and intewention.
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