Kawasaki Disease Mimicking Retropharyngeal Abscess only 2 cc of pus, which were sterile on bacterial cultures. In light of the upper airway obstruction and dysphagia with only a scant aspirate, a tracheostomy was done. His pain reduced post surgery, but the fever and swelling persisted. He was started on amikacin and metronidazole continuing cefotaxim. On day 3, his fever persisted but the swelling reduced in size and there was no dysphasia or respiratory difficulty, and thus he was decannulated and stable. For the next few days he was febrile. During this period the ultra- sonography of his abdomen, chest radiograph, echocardio- graphy, and repeat blood and urine cultures were all normal. During the 9th day of his illness, with a persisting fever he developed a bilateral non-purulent bulbar conjunctival injection and erythema of the hands and feet. On the 10th day he developed a polymorphous generalized erythematous rash and a systolic murmur. Investigations at this point in time revealed a total count of 15,100/mm3 with polymor- phonuclear leucocytosis, elevated ESR 110 mm/hr, CRP- 192 mg/dL, and a platelet count of 9.5 lac/mm3. The repeat echocardiogram revealed a fusiform aneurysm of the proximal and mid right coronary artery 6.5×6 mm. The left main, anterior descending and circumflex coronary arteries were normal. The left ventricular systolic and diastolic functions were normal with an ejection fraction of 68% and a fractional shortening of 37%. There was no pericardial effusion. With these constellation of clinical and laboratory features, the diagnosis of Kawasaki disease was entertained and he was started on intravenous immune globulin (IVIG) 2 g/kg over 24 hours along with aspirin of 100 mg/kg/day. Within 36 hours he became afebrile; his murmur disappeared and he was cheerful. On the follow- up after 14 days he was afebrile, with an ESR of 48 mm/hr, and platelet count of 4.7 lacs/mm3. His repeat echocar- diogram (ECHO) at 2 weeks still showed fusiform aneu- rysmal dilatation of the proximal and mid right coronary artery 6.5×6 mm and he continues to be on a low dose aspirin. DISCUSSION Kawasaki disease is a mucocutaneous vasculitis primarily affecting infants and young children.1 The etiology of KD remains unknown, but clinical and epidemiological studies support an infectious etiology.2 A diagnosis is based on the presence of prolonged fever (more than five days duration) plus four of the following five signs: conjunctival injection, changes in the oral mucous membranes, changes in the peripheries (erythema of the palms and soles, swelling of the hands and feet), rash, and cervical lymphadenopathy. There is no specific diagnostic test for KD and non-speci- fic laboratory findings like thrombocytosis, increased eryth- Fig. 1. CT scan showing hypointense lesion between C2-C6 levels in posterior pharyngeal space. rocyte sedimentation rate and an elevated CRP may sup- plement the diagnosis. Lymphodenopathy is the least constant of the diagnostic features of KD occurring in 50- 75% of the patients, the other clinical criteria occurring in 90%.3 It has been reported that some patients may not fulfill the above criteria for KD but still develop coronary artery disease and are diagnosed as having incomplete KD.4 Some of the unusual presentations reported in KD include renal impairment,4 acute otitis media, pulmonary infiltrates, abdominal pain, arthritis, lymphadenitis,2 peri- tonsillar abscess,5 and retropharyngeal abscess. Medline search revealed 6 earlier case reports of KD with an initial presentation of retropharngeal abscess.6-10 CT neck in those cases including the present case revealed hypodense lesions with or without contrast enhancements suggestive of retro- pharyngeal abscess and cases manifested with signs and symptoms of KD subsequently during the treatment for retropharyngeal abscess. None of the patients in those reports had coronary artery abnormalities in contrast to our patient who had developed aneurysmal dilatation of the right coronary artery. It is well-known that all criteria for KD need not be present at the same time and can appear in sequence. Thus, the diagnosis of KD in the absence of its typical features needs a high index of clinical suspicion. In our patient, there were no early clues except for a fever and all the criteria for KD only appeared in sequence later. It has been reported that once a patient is diagnosed with KD, the abscess-like lesion on the CT scan should be viewed as a type of inflammation rather than infection11 and this could be one of the reasons why the pus culture was sterile. Early recognition and aggressive medical treatment is crucial to reduce the occurrence of sudden death in adolescence and early adulthood due to coronary artery involvement. Recent Yonsei Med J http://www.eymj.org Volume 51 Number 5 September 2010 785