Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 
Visit old site
Home Print this page Email this page Small font size Default font size Increase font size
Users Online: 9


 
 Table of Contents  
LETTER TO EDITOR
Year : 2012  |  Volume : 4  |  Issue : 10  |  Page : 520-522

Hydranencephaly: A rare cause of an enlarging head size in an infant


Department of Radiodiagnosis, Jawaharlal Nehru Medical College and Hospital, AMU, Aligarh, India

Date of Web Publication4-Oct-2012

Correspondence Address:
Saifullah Khalid
Department of Radiodiagnosis, Jawaharlal Nehru Medical College and Hospital, AMU, Aligarh
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1947-2714.102015

Rights and Permissions

How to cite this article:
Khalid M, Khalid S, Zaheer S, Redhu N, Ekramullah. Hydranencephaly: A rare cause of an enlarging head size in an infant. North Am J Med Sci 2012;4:520-2

How to cite this URL:
Khalid M, Khalid S, Zaheer S, Redhu N, Ekramullah. Hydranencephaly: A rare cause of an enlarging head size in an infant. North Am J Med Sci [serial online] 2012 [cited 2020 May 31];4:520-2. Available from: http://www.najms.org/text.asp?2012/4/10/520/102015

Dear Editor,

Hydranencephaly is a rare congenital abnormality characterized by absence and replacement of the cerebral hemispheres by a large cerebrospinal fluid pool. It is thought to be caused by occlusion of bilateral internal carotid arteries in the fetal life mainly during the second trimester due to a variety of causes. [1],[2] It is one of the recognized forms of brain malformations which is usually associated with intrauterine fetal demise and is therefore rarely seen in postnatal life. [3] It is a rare entity with a reported incidence of less than 1 per 10,000 live births. [4]

A 4-month-old preterm infant was brought by his parents to the pediatric outpatient department with complaints of recent onset of fever and progressively enlarging head size. The fever was of moderate degree and was not associated with chills and rigors. According to the parents, the size of the baby's head was normal at the time of birth but it started increasing after one week of life. On examination, the child was lethargic with increased occipito-frontal circumference and there was hypotonia in all the four limbs. There was no associated cranio-facial dysmorphism or limb deformity. The mother also reported that the eyes of the child showed roving movement. The primitive reflexes, such as grasp and suction, were intact. He responded only to sound and painful stimuli and a lack of awareness to the surroundings was noted. The fundus examination of the child was normal. The mother was neither diabetic nor hypertensive; she was not a smoker and had never ingested alcohol. There was no history of radiation exposure or febrile illness and exanthematous skin rash during pregnancy. She did not undergo any ultrasound examination during the antenatal period. There was no history of consanguinity or similar complaints in the other siblings. After admission, he was managed with a working diagnosis of complicated tubercular meningitis. Mantoux test and CSF examination were normal. The baby was then referred for computed tomography (CT) of the head.

Axial CT of the head showed complete absence of B/L cerebral hemispheres with no cortical mantle and their replacement by fluid [Figure 1]. However, entire falx was preserved excluding holoprosencephaly. Also thalamus, pons, medulla, and cerebellar hemispheres were relatively preserved [Figure 2], all in keeping with the diagnosis of hydranencephaly. Somatosensory evoked potentials (SSEP) showed complete absence of the cortical activity with preservation of waves of brainstem origin. Electroencephalogram revealed a flat pattern. The visual evoked potential was absent bilaterally. The parents of the baby were counseled for poor prognosis of the condition and the minimal risk of recurrence in subsequent pregnancies. They refused any active surgical intervention.

Hydranencephaly is a rare encephalopathy that occurs in-utero and presents rarely in postnatal period. The posterior fossa structures as well as parts of the temporal and occipital lobe supplied by posterior cerebral arteries are usually preserved. [1],[5] However, cases with cerebellar hypoplasia and occlusion of bilateral posterior cerebral arteries have been reported. [1] This rare disorder usually occurs after ventricles have already formed; hence, the falx is preserved. Hydranencephaly is associated with various congenital anomalies, including arthrogryposis, renal aplastic dysplasia, poly-valvular heart defect, trisomy 13 and Fowler syndrome. [6]
Figure 1: Non-contrast axial CT image shows (a) complete destruction of bilateral cerebral hemispheres with no evidence of cortical mantle with preserved midbrain and (b)falx cerebri

Click here to view
Figure 2: Non-contrast axial CT image shows relatively normal cerebellar hemispheres, brainstem, and bilateral thalami

Click here to view


Most common etiologies described for hydranencephaly are occlusion of the supra-clinoid segment of bilateral internal carotid arteries, [1] or an extreme form of leukomalacia formed by confluence of multiple cystic cavities. Other etiologies include fetal hypoxia due to maternal exposure to carbon monoxide or butane gas resulting in massive tissue necrosis with cavitation and resorption of necrotized tissue and necrotizing vasculitis or local destruction of the brain tissue secondary to intrauterine infections, e.g. congenital toxoplasmosis, cytomegalovirus and herpes simplex. [4],[7]

Hydranencephaly can be diagnosed using ultrasound (ante- and postnatal), Magnetic Resonance Imaging (ante- and postnatal) and CT. The radiological features include almost complete absence of cortical mantle. The cranium is completely filled with membranous sac containing cerebrospinal fluid. The skull may be normal-sized or enlarged as was seen in the present case. The falx cerebri and tentorium cerebelli are usually intact. Thalamus, hypothalamus and choroid plexus are preserved and cerebellum is intact. [1],[4] The electrophysiological studies confirm the imaging findings. Prolonged survival upto 22 years has been reported in literature with significant associated morbidity. [3],[8] Ventriculo-peritoneal shunting has been tried with limited success because of frequent need for shunt revision or removal and associated poor prognosis for psychomotor development. [9] Recently, endoscopic choroid plexus coagulation is being explored as an alternative to shunting. [10]

The condition needs to be differentiated from severe obstructive hydrocephalus and severe open lip schizencephaly, however, in both these conditions, the cortical mantle is only reduced in thickness. Alobar holoprosencephaly can be differentiated by the presence of falx and frequent coexisting midline facial abnormalities.

Thus, hydranencephaly should also be considered in the differential diagnosis of an infant presenting with enlarging head size, especially in children with psychomotor retardation.

 
  References Top

1.Kelly TG, Sharif UM, Southern JF, Gururajan K, Segall HD. An unusual case of hydranencephaly presenting with an anterior midline cyst, a posterior calcified mass, cerebellar hypoplasia and occlusion of the posterior cerebral arteries. Pediatr Radiol 2011;41:274-7.  Back to cited text no. 1
[PUBMED]    
2.Stevenson DA, Hart BL, Clericuzio CL. Hydranencephaly in an infant with vascular malformations. Am J Med Genet 2001;104:295-8.  Back to cited text no. 2
[PUBMED]    
3.McAbee GN, Chan A, Erde EL. Prolonged survival with hydranencephaly: Report of two patients and literature review. Pediatr Neurol 2000;23:80-4.  Back to cited text no. 3
[PUBMED]    
4.Kurtz AB, Johnson PT. Diagnosis please. Case 7: Hydranencephaly. Radiology 1999;210:419-22.  Back to cited text no. 4
[PUBMED]    
5.Taori KB, Sargar KM, Disawal A, Chhadi S, Rathod J. Hydranencephaly associated with cerebellar involvement and bilateral microphthalmia and colobomas. Pediatr Radiol 2011;41:270-3.  Back to cited text no. 5
[PUBMED]    
6.Usta IM, AbuMusa AA, Khoury NG, Nassar AH. Early ultrasonographic changes in Fowler syndrome features and review of the literature. Prenat Diagn 2005;25:1019-23.  Back to cited text no. 6
[PUBMED]    
7.Christie JD, Rakusan TA, Martinez MA, Lucia HL, Rajaraman S, Edwards SB, et al. Hydranencephaly caused by congenital infection with herpes simplex virus. Pediatr Infect Dis 1986;5:473-8.  Back to cited text no. 7
[PUBMED]    
8.Bae JS, Jang MU, Park SS. Prolonged survival to adulthood of an individual with hydranencephaly. Clin Neurol Neurosurg 2008;110:307-9.  Back to cited text no. 8
[PUBMED]    
9.Adeloye A. Hydranencephaly in Malawian children. East Afr Med J 2000;77:316-8.  Back to cited text no. 9
[PUBMED]    
10.Sandberg DI, Chamiraju P, Zoeller G, Bhatia S, Ragheb J. Endoscopic choroid plexus coagulation in infants with hydranencephaly or hydrocephalus with a minimal cortical mantle. Pediatr Neurosurg 2012. Jul 21. (Epub ahead of print)  Back to cited text no. 10
    


    Figures

  [Figure 1], [Figure 2]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
References
Article Figures

 Article Access Statistics
    Viewed2406    
    Printed54    
    Emailed0    
    PDF Downloaded344    
    Comments [Add]    

Recommend this journal