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 Table of Contents  
Year : 2018  |  Volume : 6  |  Issue : 2  |  Page : 265-266

Transient bulging of the anterior fontanel

Department of Paediatrics, National Postgraduate Medical College of Nigeria, Aminu Kano Teaching Hospital, Bayero University, Kano, Nigeria

Date of Web Publication27-Dec-2018

Correspondence Address:
Dr. Ibrahim Aliyu
Department of Paediatrics, Aminu Kano Teaching Hospital, Bayero University, Kano
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/amhs.amhs_114_17

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Bulging of the anterior fontanel could be an ominous sign, especially when associated with other signs or symptoms of raised intracranial pressure. However, some benign conditions have also been reported with bulging of the anterior fontanel such as following Rotaviral gastroenteritis, respiratory tract infection, rosella infantum infection, and vaccination. This is usually transient and its exact mechanism is not completely understood. Therefore, the case of a 5-month-old boy who had a bulging anterior fontanel following treatment for meningitis, which was confused with postmeningitic hydrocephalus, is reported.

Keywords: Idiopathic intracranial hypertension, meningitis, pseudotumor cerebri, transient bulging of anterior fontanel

How to cite this article:
Aliyu I. Transient bulging of the anterior fontanel. Arch Med Health Sci 2018;6:265-6

How to cite this URL:
Aliyu I. Transient bulging of the anterior fontanel. Arch Med Health Sci [serial online] 2018 [cited 2022 Jun 28];6:265-6. Available from: https://www.amhsjournal.org/text.asp?2018/6/2/265/248654

  Introduction Top

A bulging anterior fontanel may be indicative of a rise in intracranial pressure, especially in children who are febrile, irritable, and unconscious. Therefore, common causes of bulging fontanel include meningitis, hydrocephalus, encephalitis, and intracranial space-occupying lesions.[1],[2] However, bulging fontanel has been documented in febrile children without evidence of proven intracranial infection, this is called “idiopathic intracranial hypertension, transient bulging of the anterior fontanel of infancy, and pseudotumor cerebri (PTC).”[3],[4],[5] The exact cause and mechanism of this disorder is not completely understood but has been associated in children following febrile illness such as Rotavirus enteritis, rosella infantum infection, otitis media, and respiratory tract infection.[6],[7] PTC is characterized by intracranial hypertension in the absence of intracranial space-occupying lesion or dilatation of the ventricles. PTC is a rare condition of uncertain etiology; it is more common in adult females between the ages of 20 and 44 years, and common risk factors are obesity, drugs such as contraceptives, diabetes mellitus, polycystic ovary syndrome, and also in patients with dural venous stenosis or thrombosis.[8] However, the case of a 5-month-old child who presented with bulging of the anterior fontanel following treatment for meningitis is reported.

  Case Report Top

A 5-month-old boy presented a week after treatment for bacterial meningitis in our health facility with bulging of the anterior fontanel. There was no history of fever, vomiting, or diarrhea, there was no ear tugging or discharge, and he was not irritable or excessively crying. He was treated for bacterial meningitis which grew Streptococcus pneumoniae and was discharged after 2 weeks on admission without any sequel. The examination findings were not remarkable, except for the bulging anterior fontanel. It measured 3 cm × 3 cm bulging, [Figure 1]; it was nonpulsatile and no signs of lateralization were detected. The occipitofrontal circumference was 44 cm which was normal for age. The cardiovascular and respiratory examinations were essentially normal. The cerebrospinal fluid (CSF) analysis results from the referral note read as follows: CSF white blood cell count was 110 cells/uL; CSF glucose was 30 mg/dL (random blood sugar was 108 mg/dL); and CSF protein was 150 mg/dL. CSF Gram stain showed Gram-positive diplococci organisms while the culture was S. pneumoniae. Based on the findings, the diagnosis of hydrocephalus was made; however, both the transfontanel ultrasound and brain-computed tomography scan were normal [Figure 2]. The parents were counseled, and the child was follow-up, and the bulge resolved spontaneously after 1 week. The final diagnosis of transient bulging fontanel of infancy was made.
Figure 1: A bulging anterior fontanel

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Figure 2: Normal brain computed tomography

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  Discussion Top

Transient bulging of the anterior fontanel is a diagnosis of exclusion; however, several theories have been put forward explaining the mechanism of trajectory-based forwarding (TBF), Quincke in his submission, attributed it to imbalance in the CSF homeostasis, which could be due to excessive CSF production or due to failure of CSF absorption resulting in excessive CSF and elevation of intracranial pressure.[9] This may occur following meningitis with inflammation of the arachnoid villi hence impairing CSF absorption; critics of this hypothesis often cite lack of consistent improvement/resolution of symptoms following lumbar puncture to support their claims, and they also argue that there should be expectant increase in ventricular size as it is observed in patients with hydrocephalus due to obstruction of CSF flow. The second theory emphasizes the importance of venous outflow obstruction which may be thrombotic or stenotic in elevating the total cerebral blood volume hence increasing the intracranial pressure. Thrombosis of the venous sinus may be seen in children with complicated otitis media and complicated meningitis following vasculitis.

There are no established diagnostic criteria for TBF in infancy; common complaints associated with IIH in adolescents and adults such as a headache and blurred vision are not reported in infancy. However, the commonly observed complaint in infancy is irritability, increased occipitofrontal circumference, somnolence, apathy, vomiting, and bulging anterior fontanel. The neuroimaging is characteristically normal. The opening pressure is often elevated which may be >20 cm of water though lumbar puncture was not done in the index case because the initial diagnosis was postmeningitic hydrocephalus.

The main concern in the management of IIH is visual loss; lumbar puncture may give a transient relieve of symptoms; and medications such as the carbonic anhydrase inhibitors – acetazolamide and diuretics such as furosemide have been used to reduce CSF production and volume, respectively.[10] In severe cases, more aggressive measures such as ventriculoperitoneal shunt may be done to improve CSF flow. Ophthalmologists advocate optic nerve sheath fenestration as a decompression measure. In patients with dural venous stenosis, stenting of the stenotic venous sinus will improve its patency. However, our patient improved spontaneously without any active intervention.

  Conclusion Top

Transient bulging of the anterior fontanel may occur following meningitis, and the presentation is variable as in the index case whose only complaint was a bulging anterior fontanel.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Freedman SB, Reed J, Burwen DR, Wise RP, Weiss A, Ball R. Transient bulging fontanelle after vaccination: Case report and review of the vaccine adverse event reporting system. J Pediatr 2005;147:640-4.  Back to cited text no. 1
Rangwala LM, Liu GT. Pediatric idiopathic intracranial hypertension. Surv Ophthalmol 2007;52:597-617.  Back to cited text no. 2
Johnston I, Hawke S, Halmagyi M, Teo C. The pseudotumor syndrome. Disorders of cerebrospinal fluid circulation causing intracranial hypertension without ventriculomegaly. Arch Neurol 1991;48:740-7.  Back to cited text no. 3
Pearce JM. From pseudotumour cerebri to idiopathic intracranial hypertension. Pract Neurol 2009;9:353-6.  Back to cited text no. 4
Johnston I. The historical development of the pseudotumor concept. Neurosurg Focus 2001;11:E2.  Back to cited text no. 5
Shacham S, Kozer E, Bahat H, Mordish Y, Goldman M. Bulging fontanelle in febrile infants: Is lumbar puncture mandatory? Arch Dis Child 2009;94:690-2.  Back to cited text no. 6
Taşdemir HA, Dilber C, Totan M, Onder A. Pseudotumor cerebri complicating measles: A case report and literature review. Brain Dev 2006;28:395-7.  Back to cited text no. 7
Sylaja PN, Ahsan Moosa NV, Radhakrishnan K, Sankara Sarma P, Pradeep Kumar S. Differential diagnosis of patients with intracranial sinus venous thrombosis related isolated intracranial hypertension from those with idiopathic intracranial hypertension. J Neurol Sci 2003;215:9-12.  Back to cited text no. 8
Levine DN. Ventricular size in pseudotumor cerebri and the theory of impaired CSF absorption. J Neurol Sci 2000;177:85-94.  Back to cited text no. 9
Wall M. Idiopathic intracranial hypertension. Neurol Clin 2010;28:593-617.  Back to cited text no. 10


  [Figure 1], [Figure 2]


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