Recognition of retropharyngeal abscess in children

American Family Physician,  July, 1992  by Richard W. Hartmann

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Retropharyngeal abscess usually occurs in infants and young children. This infection can be life-threatening because it is capable of causing sudden respiratory obstruction.

In the first couple years of childhood, several lymph nodes are present in the space between the posterior pharyngeal wall and the prevertebral fascia. These lymph nodes atrophy by three to four years of age. Infection of these lymph nodes occurs secondary to infection of the nasopharynx, paranasal sinuses or middle ear.[1] In the usual mechanism, lymphatic drainage causes a retropharyngeal adenitis to occur, which then suppurates. A recent survey of a 36-year experience with retropharyngeal abscess revealed that the disease is occurring later in childhood and may not always be preceded by a detectable infection.[2] Other causes of retropharyngeal abscess include foreign-body penetration and penetrating trauma to the neck.[3]

The most common symptoms of retropharyngeal abscess are fever, swollen neck, difficult swallowing, a muffled voice and hyperextension of the head and neck. Retropharyngeal abscess can mimic croup, epiglottitis (or supraglottitis), tracheitis and uvulitis.[4]

Illustrative Case

A 13-month-old boy was brought to the emergency department because of fever, a swollen neck, congestion, lethargy and poor intake of both liquid and solid foods. The child had been taking very small amounts of liquid by mouth, and his diapers had not been as wet as usual. He was not hoarse or coughing and had no recent choking episode.

Physical examination revealed an infant in respiratory distress. His weight was 9.4 kg (20 lb, 12 oz; in the 15th percentile), and his height was 80 cm (32 in; in the 75th percentile). His temperature was 40 [degrees] C (104 [degrees]F) rectally; heart rate, 164 per minute, and respiratory rate, 44 per minute. The child drooled and gurgled with inspiration and expiration and preferred to keep his neck hyperextended. Enlarged anterior cervical lymph nodes were palpable; they were not hard or tender and measured 0.5 to 1.0 cm in diameter. Throat examination revealed normal tonsils with no exudate or erythema. The lips and tongue were pink. The eardrums were normal. Much white nasal mucus was seen. The remainder of the examination was normal.

Laboratory studies showed a white blood cell count of 33,600 per [mm.sup.3] (33.6 x [10.sup.9] per L) with a differential of 69 percent (0.69) segmented neutrophils, 10 percent (0.10) band cells, 20 percent (0.20) lymphocytes and 1 percent (0.01) basophils; hematocrit, 30.7 percent (0.307), and hemoglobin, 9.9 g per dL (99 g per L), which was greater than two standard deviations below the mean for a child of 13 months. Electrolyte, blood urea nitrogen and glucose levels were normal. Blood culture was sterile after seven days.

Frontal and lateral films of the neck (Figures 1 and 2) were obtained. A computed tomographic (CT) scan of the neck was also obtained (Figures 3 and 4).

Following admission, intravenous oxacillin was started, 500 mg every six hours (200 mg per kg per day). On the second hospital day, the child's rectal temperature was 38 [degrees] C (100.4 [degrees]F), but his respiratory distress had not improved. In fact, drooling and increasing respiratory obstruction prompted the decision to surgically drain the abscess. Postoperative convalescence was rapid, with prompt disappearance of the respiratory distress.

Culture of the abscess revealed Streptococcus equisimilis, a group C betahemolytic streptococcus.

Intravenous oxacillin was continued for 10 days, and the infant was then discharged from the hospital.

Discussion

A lateral radiograph of the neck confirms the diagnosis of retropharyngeal abscess in many cases and should be considered in any patient with symptoms of respiratory distress. The film should be taken during inspiration, with the neck extended. The retropharyngeal soft tissue normally is no more than one-half the width of the adjacent vertebral body.[5] Figure 5 lists the normal width of the posterior pharyngeal soft tissue according to the patient's age. CT scanning is also important for the early diagnosis and treatment of this unusual entity.[6]

Results from aspiration of retropharyngeal abscesses in 14 patients show that anaerobic bacteria played a major etiologic role in two-thirds of the patients.[7] S. equisimilis, the pathogen in the illustrative case, is the most common species of group C streptococcus associated with human infection. The organism is susceptible to all antibiotics.

Early diagnosis and treatment of retropharyngeal abscess are crucial to minimize the risk of mediastinal spread of the infection, aspiration of pus, acute respiratory obstruction and erosion of the internal jugular vein and carotid artery.[8]

REFERENCES

[1.] Behrman RE, Vaughan VC 3d, Nelson WE, eds. Nelson Textbook of pediatrics. 13th ed. Philadelphia: Saunders, 1987:873-4. [2.] Thompson JW, Cohen SR, Reddix P. Retropharyngeal abscess in children: a retrospective and historical analysis. Laryngoscope 1988;98(6 Pt 1):589-92. [3.] Ross MN, Janik JS. |Foil tab' aspiration and retropharyngeal abscess in a toddler [Letter]. JAMA 1988;260:3130. [4.] Morrison JE Jr, Pashley NR. Retropharyngeal abscesses in children: a 10-year review. Pediatr Emerg Care 1988;4:9-11. [5.] Swischuk LE. Emergency radiology of the acutely ill or injured child. 2d ed. Baltimore: Williams & Wilkins, 1986:127-45. [6.] Dodds B, Maniglia AJ. Peritonsillar and neck abscesses in the pediatric age group. Laryngoscope 1988;98:956-9. [7.] Brook I. Microbiology of retropharyngeal abscesses in children. Am J Dis Child 1987; 141:202-4. [8.] Ramilo J, Harris VJ, White H. Empyema as a complication of retropharyngeal and neck abscesses in children. Radiology 1978;126: 743-6. RICHARD W. HARTMANN, M.D. is pediatric coordinator of the family practice residency program at Halifax Medical Center, Daytona Beach, Fla., and clinical assistant professor in family medicine at the University of South Florida College of Medicine, Tampa. A graduate of Hahnemann University School of Medicine, Philadelphia, Dr. Hartmann served a pediatric residency at Saint Christopher's Hospital for Children, Philadelphia, and at the University of Oregon Medical School Hospital, Portland.

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