98 Alsoub, Chacko Postgrad Med J: first published as 10.1136/pgmj.71.832.98 on 1 February 1995. Downloaded from Descending necrotising mediastinitis Hassam Alsoub, Kadavil C Chacko Summary heart, bilateral pleural effusion, and pericardial Descending necrotising mediastinitis is a effusion (figures 1 and 2). Cephalothin was rare but serious complication of discontinued and intravenous imipenem/ oropharyngeal infections with high mor- cilastatin 500 mg every six hours was started, tality. Diagnosis is frequently delayed, and surgical drainage was carried out through a contributing to this high mortality, but transcervical incision. Culture of the pus grew awareness of such a complication and Streptococcus viridans. Two days later chest early diagnosis using computed tomo- X-ray showed further widening of the medias- graphic scanning leads to prompt sur- tinum, a large left pleural effusion, and an gical drainage, proper antibiotic therapy, echocardiogram showed a large pericardial and survival. effusion. Mediastinal drainage was done again through a subxiphoid incision and pericardial Keywords: descending necrotising mediastinitis, CT and left pleural tubes were inserted yielding scanning purulent fluids. The patient's condition then improved gradually and the mediastinal drain, pericardial, and left pleural tubes were Introduction removed on the 20th hospital day. Imipenem/ cilastatin was continued for total of six weeks; Acute suppurative mediastinitis is a severe the patient was then discharged home in good infectious condition that is most commonly the health. result of oesophageal perforation or rupture. Oropharyngeal infections may cause descen- ding necrotising mediastinitis characterised by rapid tissue destruction and high mortality unless vigorous and effective therapeutic measures are taken. Three cases of descending necrotising mediastinitis secondary to periton- sillar abscess have been reported previously. Over the last two years we have treated two http://pmj.bmj.com/ patients with descending necrotising medias- tinitis secondary to peritonsillar abscess. The clinical courses of these two patients are des- cribed and previous publications reviewed. Case 1 A 32-year-old previously healthy man present- on September 24, 2021 by guest. Protected copyright. ed with a four-day history of sore throat, difficulty in swallowing, and fever. Physical Figure 1 CT scan at the level of larynx showing examination revealed a pyrexia of 40.8'C, extensive gas-forming infection involving both sides of blood pressure of90/60 mmHg and a pulse rate the neck of 135 beats/min. Examination of the throat revealed a right peritonsillar abscess, but other- wise physical examination was normal. Laboratory investigation on admission revealed a haemoglobin of 13.0 g/dl, white blood cell count of 7.6 x 109/1, and platelets 14.7 x 109/1. Liver function tests, serum creatinine and chest X-ray were normal. Hamad Medical Incision of the abscess yielded a small amount Corporation, Doha, of bloody fluid but no culture was done. The Qatar patient was started on intravenous cephalothin H Alsoub 500 mg every six hours. On the fifth hospital KC Chacko day he developed rapidly increasing swelling Correspondence to involving both sides of the neck and suprac- H Alsoub, Hamad Medical lavicular regions with crepitus. A computed Corporation, PO Box 3050, tomographic (CT) scan of the chest demon- Doha, Qatar Figure 2 CT scan at the level of the heart showing strated an abscess with gas collection in the extension of the infection to the anterior mediastinum Accepted 29 July 1994 anterior mediastinum down to the level of the and pericardium Descending necrotising mediastinitis 99 Case 2 Discussion A 47-year-old man with insulin-dependent diabetes mellitus was admitted with a 24-h Acute mediastinitis is an uncommon condition; Postgrad Med J: first published as 10.1136/pgmj.71.832.98 on 1 February 1995. Downloaded from history of throat pain and trismus. Physical it is mostly seen as a complication of examination revealed a temperature of 37.9°C, oesophageal perforation or following cardiac pulse rate of 104 beats/min and blood pressure surgery. Acute mediastinitis unrelated to sur- 210/120 mmHg. Throat examination revealed gical procedures was considered a rare infec- a right peritonsillar abscess. Laboratory inves- tion even in the pre-antibiotic era.' Today, tigation on admission revealed: a haemoglobin liberal and early antibiotic utilisation has made 12.3 g/dl, white blood cell count 16.4 x 109/1, this condition even more rare, but it is still seen platelet 30.4 x 109/1, random blood sugar as a complication of infection in the 14.6 mmol, serum creatinine 220 ttmol/l, and oropharynx, or second and third mandibular normal chest X-ray film. He was started on molar with dissection downward along the intravenous cephalothin 1.5 g every six hours anatomic fascial planes to the mediastinum. with slight improvement. On the sixth hospital Such a variety is called descending necrotising day incision of the abscess was carried out but mediastinitis. Pearse2 in 1938 reported one of only a small amount of blood was obtained. the first series of patients with mediastinitis Intravenous clindamycin (600 mg every six following orodental infections. He described hours) was added. On the 1 1th hospital day he 100 patients, 64 of whom were the result of developed swelling in the anterior aspect ofthe oesophageal perforation while only 21 were the neck and both supraclavicular regions, more in result of oropharyngeal infection and in this the right side, with no crepitus. A CT scan of group he reported a mortality of more than neck and chest demonstrated a right peritonsil- 50%. Over 50 further cases of descending lar abscess 3 cm in diameter and an abscess necrotising mediastinitis have now been extending from the left oropharynx down to the reported.''8 We adopted the criteria proposed mediastinum anterior to the trachea and behind by Estrera et al3 for the diagnosis ofdescending the arch ofthe aorta with air bubbles (figures 3, necrotising mediastinitis (see box). 4). Transcervical draining of the mediastinum The group consisted of 36 males, 10 females was done, but culture of the pus failed to grow and five patients for whom sex was not any organism. After that the patient continued specified. Ages ranged from one month to 64 to improve gradually. Imipenem/cilastatin was years with an average of 33.5 years. The most continued for a total of 30 days, then he was common cause was odontogenic infection discharged home in good health. usually arising from second and third man- dibular molars (table). Patients with acute mediastinitis are often severely ill (see box overleaf). Most recent studies have emphasized the polymicrobial nature of these infections.2"3 The organisms involved in descending nec- rotising mediastinitis are usually mixed aerobes and anaerobes, accounting for 47% of cases, aerobes only (usually B-haemolytic streptococ- http://pmj.bmj.com/ cus) account for 23% and anaerobes only 30% of cases.3 These usually reflect the organisms present in the mouth. The ... :... ::. synergistic action of ':4Bgi::..,;;. Criteria for diagnosis of descen- on September 24, 2021 by guest. Protected copyright. ding necrotising mediastinitis Figure 3 Post-contrast CT scan of the neck showing an abscess in the left para-pharyngeal space with ring * clinical manifestation of severe infection enhancement * characteristic X-ray features ofmediastinitis * necrotising mediastinal infection at operation or post-mortem * relationship to oropharyngeal infection, with the development ofthe necrotising process ,e .g.X ....c.: .' Table Conditions causing descending necrotising mediastinitis Cause No of patients Odontogenic infection 31 Retropharyngeal abscess 6 Peritonsillar abscess 3 Cervical lymphadenitis 2 Trauma 3 Endotracheal intubation 5 Figure 4 Post-contrast CT scan at the level of the Unknown 1 thyroid gland, showing extension ofthe infection down- wards with the gas formation Total 51 100 Alsoub, Chacko extends from the skull base inferiorly into the Descending necrotising posterior mediastinum to the diaphragm. mediastinitis Infections of the second and third mandibular Postgrad Med J: first published as 10.1136/pgmj.71.832.98 on 1 February 1995. Downloaded from Clinical features molars may result in submandibular triangle * severely ill abscess. By extension ofthe abscess beyond the * fever, tachycardia posterior limit of the mylohyoid shelf, involve- * oedema ofneck or chest wall with crepitus ment of the retrovisceral space can occur with * purulent pleural and/or pericardial effusion subsequent involvement of the mediastinum. Spread of infection from the oropharynx to the mediastinum is enhanced by gravity and the negative intrathoracic pressure. aerobic and anaerobic organisms may explain The standard and most commonly used the virulence of these infections. approach to drain the mediastinum is the In the evaluation of cases of descending trans-cervical approach. However, many necrotising mediastinitis the use of X-ray authorities in this field believe that this ap- examination of the neck and chest is not very proach may be inadequate and even may delay helpful. It may show widening of the medias- definitive operation to drain the medias- tinum with gas bubbles, however, these find- tinum.34 They recommend an approach which ings are usually late in the course ofthe disease. depends on the CT scan finding at the time of CT scan has proved to be a very useful aid in diagnosis.