PAUL L. ARONSON
HISTORY OF PRESENT ILLNESS
A 2-month-old male presented with a 3-day history of neck swelling and 1 day of neck redness. The parents did not notice any swelling prior to the past 3 days. He has had a fever at home for 1 day. His oral intake has been adequate. The patient had no emesis, diarrhea, respiratory symptoms, or rash elsewhere on the body. There was no cat or TB exposure.
The patient was born at term during an uncomplicated delivery. There have been no hospitalizations. The patient had not yet received any immunizations. There were no known allergies and the patient had not received any medications. Family history is notable for no significant illnesses. The mother and father had arrived from West Africa 6 months ago.
T 38.5°C; HR 176 bpm; RR 44/min; BP 112/76 mmHg; SpO2 97% in room air; Weight 6.2 kg (75th-90th percentile); Length 60 cm (90th percentile); Head Circumference 41 cm (90th percentile)
The infant was not in any distress. The head was normocephalic and the anterior fontanelle was open and flat. The oropharynx was clear. A tender, mildly indurated erythematous mass arose in the superior portion of the neck at the angle of the jaw. There was no fluctuance. The lung and heart sounds were normal. There was no hepatomegaly, and no axillary or inguinal lymphadenopathy.
The complete blood count revealed the following: 15 300 WBCs/mm3 (9% band forms, 65% segmented neutrophils, and 26% lymphocytes); hemoglobin, 11.7 g/dL; platelets, 296 000/mm3. Serum electrolytes revealed the following: sodium, 135 mEq/L; potassium, 5.3 mEq/L; chloride, 103 mEq/L; bicarbonate, 24 mEq/L; blood urea nitrogen, 4 mg/dL; creatinine, 0.2 mg/dL; and glucose, 113 mg/dL. Cerebrospinal fluid examination revealed 1 WBC, no RBCs, and a glucose of 68 mg/dL. There were no bacteria on gram stain. Blood, cerebrospinal fluid, and urine cultures were obtained. CT scan of neck with intravenous contrast was obtained (Figure 13-4).
FIGURE 13-4. CT scan of the neck showing a well-circumscribed lesion with a nonenhancing area of hypoattenuation posterior to the angle of the mandible (arrow) on the right side.
COURSE OF ILLNESS
The patient was admitted to receive broad-spectrum intravenous antibiotics. On day 2 of hospitalization there was significant drainage from the lesion on the neck. The patient underwent operative drainage of the mass on hospital day 3.
DISCUSSION CASE 13-3
The causes of neck masses in infants are summarized in Table 13-4. The early age of onset in this case indicated that the mass was likely congenital in origin. Congenital causes of neck masses include thyroglossal duct cyst, branchial cleft cyst, cystic hygroma, and hemangioma. An important distinguishing feature between branchial cleft cysts and thyroglossal duct cysts is the location in the neck; thyroglossal duct cysts are midline while branchial cleft cysts are lateral in the neck, usually at the anterior border of the sternocleidomastoid muscle near the angle of the mandible. The mass in this case was adjacent to the angle of the jaw, suggesting a branchial cleft cyst. In addition to the fever, the mass was warm, erythematous and increasing in size, indicating that an infection had complicated the anomaly (Figure 13-5). Other possible lateral lesions besides a branchial cleft cyst would include cystic hygroma or hemangioma. Cystic hygromas, or lymphangiomas, can be very large, and present similarly to this patient. However, they usually arise in the submental, submandibular, or supraclavicular areas and are usually nontender, although they can uncommonly be superinfected. Hemiangiomas are also often erythematous and can increase in size during early infancy, but do so more slowly. In addition, hemangiomas are vascular, nontender often raised lesions (Figure 13-6), and a hemangioma would not be expected to cause a fever. Neonatal torticollis can cause a firm, often calcified consistency lesion in the sternocleidomastoid muscle. However, redness and increasing size of the lesion do not occur; the infant’s head will be tilted toward the mass with the chin pointed opposite, and neonatal torticollis usually presents in the first 3 weeks of life. A tumor is possible but less likely in this age range. Also, a tumor would not usually have the inflammatory signs that were evident in this child. Bacterial lymphadenitis can present similarly to an infected branchial cleft cyst, with fever, erythema, swelling, and often fluctuance (Figure 13-7).
TABLE 13-4. Differential diagnosis of neck swelling in infants.
Figure 13-5 . Superinfected branchial cleft cyst located on the anterior border of the sternocleidomastoid muscle.
FIGURE 13-6. Hemangioma of the chest.
FIGURE 13-7. Acute bacterial cervical lymphadenitis.
The fever in this 2-month-old boy necessitated a full sepsis workup to evaluate for serious bacterial illness, including blood, urine, and cerebrospinal fluid cultures. For a neck mass, ultrasound is often the first line imaging modality to characterize the lesion. CT scan with intravenous contrast is obtained with concern for deeper infections of the neck, as in this case, or when ultrasound is unable to assess the full extent of the mass. For large neck masses without signs of infection, magnetic resonance imaging may be used due to the lack of ionizing radiation with this modality.
The diagnosis on CT scan is superinfected branchial cleft cyst (Figure 13-4).
INCIDENCE AND ETIOLOGY OF BRANCHIAL CLEFT CYST
Branchial cleft cysts are the most common congenital lesions presenting with neck infection. The branchial arches develop in utero, with clefts in between the arches. Branchial cleft cysts are remnants of the branchial arches and clefts that fail to involute during embryonic development, and can arise from any of the five arches. Second branchial cleft cysts, as this patient had, are the most common type of branchial arch anomaly, occurring in up to 95% of cases. These cysts usually present as masses at the anterior border of the sternocleidomastoid muscle or at the angle of the mandible. First branchial cleft cysts occur in the parotid or postauricular areas. Third branchial cleft cysts occur at the anterior border of the sternocleidomastoid muscle, near the middle to lower part of the neck, while fourth branchial cleft cysts occur in the lower neck area.
The most common presentation of a branchial cleft cyst is a painless mass in the lateral neck of a child, along the anteromedial border of the sternocleidomastoid muscle. Occasionally, a patient may present due to compressive symptoms such as respiratory or feeding difficulty from local mass effect. Presentation may occur when the previously undiagnosed cyst becomes secondarily infected, as in this case. Signs of infection include fever, redness, tenderness, and increasing swelling of the neck. Sinus tracts may also occur, with resultant purulent drainage from the mass. The clinical presentation depends on the location as noted above and state of infection of the cyst.
Ultrasound is often the first imaging study obtained, although CT scan with intravenous contrast is often used and is recommended to assess for deep neck infection. Magnetic resonance imaging may be utilized for preoperative planning.
Branchial cleft cysts are treated with surgical excision. Removing the entire cyst is often difficult and recurrences do occur if remnants are left in situ. Antibiotic treatment is used with bacterial superinfection to decrease the acute inflammatory response prior to surgery, often for 4-6 weeks prior to excision; antibiotics with activity against Gram-positive skin flora and oral anaerobes. Reasonable options include ampicillin-sulbactam, amoxicillin-clavulanate, and clindamycin. If the patient or a family member is known to be colonized with methicillin-resistant Staphylococcus aureus (MRSA) or to have recurrent skin and soft tissue infections, empiric antibiotic therapy should include agents usually effective against MRSA (e.g., clindamycin).
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