Subaponeurotic Cerebrospinal Fluid Collection in an Infant.

Subaponeurotic cerebrospinal fluid (CSF) collection is a rare condition. We report a 13-week-old male infant who presented with a swelling in the occipitoparietal region of 4 h duration. Swelling was soft, fluctuant, and contained CSF. It was tapped twice on the 4th and 8th day of appearance and resolved completely by 7 weeks. The condition is benign, and a conservative approach is recommended.

INTRODUCTION

Subaponeurotic or subgaleal cerebrospinal fluid (CSF) collection is a rare cause of swelling in young infants. It presents as a soft, ill-defined, fluctuant swelling and is not limited by suture lines. Usually, the swelling subsides without any intervention. Recently, we came across such a case, and because of its rarity and chance association with wormian bones, it is being reported.

CASE REPORT

A male infant aged 13 weeks presented with a swelling in the occipitoparietal region of 4 h duration. He was delivered by emergency cesarean section after failed ventouse attempt. No swelling was noted in the scalp in the immediate neonatal period.

At presentation, there was a soft diffuse, nontender, fluctuant, transilluminant swelling with fluid thrill in the occipitoparietal region.

Ultrasonography revealed anechoic fluid of 5.9 mm thickness [Figure 1a]. Plain X-Ray skull revealed a soft tissue shadow without any evidence of fracture. Computed tomography revealed it to be H value 11 [Figure 1b]. Brain parenchyma was normal. Volume rendering showed multiple bilateral wormian bones in the lambdoid suture [Figure 1c]. Fluid was aspirated on the 4th and 8th day of its appearance. It was blood stained, and biochemical examination showed sugar value 105 mg% and protein 64.2 mg%. Swelling reappeared in the upper part and resolved within 7 weeks from the time of its onset. The child is healthy and doing well on follow-up for the last 36 months.

Figure 1

(a) Ultrasound of the cranium showing fluid collection outside the cranium (dotted line). (b) Noncontrast computed tomogram, axial view, showing extracranial fluid collection with hounsfield unit value 11. (c) Volume-rendering computed tomogram showing multiple wormian bones on both sides in the lambdoid suture

DISCUSSION

Subaponeurotic fluid collections have been reported infrequently. These collections are obvious clinically and are often noticed a few weeks after delivery and resolve spontaneously. A few cases have been reported in which the swelling had been tapped on one or two occasions when it recurred and later resolved spontaneously within 5-24 weeks.[12]

Usually, these children are healthy, alert, and without any abnormalities of the skull; however, in our case, there were associated wormian bones. There was no evidence of these bones being responsible for CSF collections as none of the bone ossicles were directed inward to injure the dura. Usually, wormian bones are small and less numerous unless associated with skeletal dysplasia.[3]

The swellings are cystic, soft, compressible, fluctuant, and usually cross the suture lines.

The etiology of this condition is not well understood; however, it may occur due to birth trauma resulting from prolonged vacuum-assisted delivery; disruption of the lymphatic drainage, venous drainage, and CSF leakage may be contributory.[4] Schoberer et al. proposed microfractures disrupting the emissary and diploic veins.[4] Aspirates from the swellings revealed CSF, the origin of which was uncertain. This condition is more common in children monitored with fetal scalp electrodes and ventouse delivery.[25] In our case, ventouse application may have been responsible. In our patient, the CSF swelling was not noticed immediately after birth and it was diagnosed a few weeks after the birth, which has been the experience of others as well.

CSF collection does not cause periosteal ridging as seen with cephalhematoma. Aspiration of the swelling is not indicated as there is a potential risk of infection.

Hopkins et al. treated 1 of 7 patients with aspiration twice, later it resolved spontaneously.[1] Petraglia et al. could collect 12 cases from literature, and all of them were from Europe and presented three of his own.[2] Schoberer et al. reported a series of 5 cases presenting 7–8 weeks after birth. Four of these cases had ventouse delivery.[4] Fluid was aspirated in three cases (twice in one case) and fluid reaccumulated after aspiration in all three occasions. The aspirate showed high concentrations of B trace protein and B2 transferrin was present in the range of within CSF indicating that these fluid collections appeared to be related to traumatic labor because of serosanguinous nature. In our case, the fluid was slightly blood stained and biochemically confirmed it to be CSF.

CONCLUSION

Subaponeurotic CSF collection is a benign self-limiting condition which is usually seen in neonates delivered using vacuum device.

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Conflicts of interest

There are no conflicts of interest.