PICTURE OF THE MONTH

MRI Findings in Kernicterus

Smita Manchanda & Akhila Prasad &

Barindra Prasad Baruah

Received: 14 November 2011 /Accepted: 9 August 2012# Dr. K C Chaudhuri Foundation 2012

A 6- months old male infant was brought with developmen-tal delay, rigidity and movement disorder. He was born at30 wk gestation with a birth weight of 1300 g. His day 3total bilirubin levels were 15.5 mg/dl for which he hadreceived two days of phototherapy. On current neurologicalexamination, there was hypotonia, athetosis and upwardgaze palsy. Brain auditory evoked potential (BAEP) testingrevealed prolonged latency of wave I.

MRI brain revealed abnormal high signal intensity in theglobus pallidus bilaterally on T2 weighted images with mildbilateral ventricular dilatation (Figs. 1 and 2).

The neurological and imaging features are suggestive ofathetoid cerebral palsy due to kernicterus.

Kernicterus is a neurologic condition resulting from thedeposition of unconjugated bilirubin within the brain [1].Causes of hyperbilirubinemia include erythroblastosis feta-lis, hemolytic anemia (G-6-PD deficiency), sepsis and de-hydration. Free unconjugated bilirubin can enter brain and istoxic to synapses and axons. Reduced albumin levels andacidosis also play a contributory role in the occurrence ofpreterm kernicterus at relatively low bilirubin levels [2].

The neurological features in the acute phase include poorfeeding, lethargy, high pitched cry, hyper- or hypotonia,opisthotonus, seizures, fever, thermal instability and incom-plete Moro’s reflex. Choreoathetosis, upward gaze palsy,tremors, seizures, sensorineural hearing loss and intellectualdeficits maybe seen in the chronic phase [3]. Preterminfants may develop kernicterus even in the absence of acutesymptoms [4].

MRI findings in kernicterus are characterized by abnor-mal high signal intensity on T2 weighted imaging in thebilateral globi pallidi, especially the posteromedial border[4]. This corresponds to known areas of preferential depo-sition of unconjugated bilirubin. In the acute phase, pallidalinjury may be seen as T1 hyperintensity [2]. The differentialfor bilateral basal ganglia T2 hyperintensities includes acuteconditions like carbon monoxide poisoning, hypoxia, hypo-glycemia and chronic conditions like inborn errors of me-tabolism (methyl malonic acidemia), mitochondrialdisorders (Leigh’s syndrome) and dysmyelinating disorders[1,5].

Fig. 1 Coronal T2 weighted MR image shows abnormal high signalintensity in bilateral globus pallidus (arrows)

S. Manchanda (*) :A. Prasad :B. P. BaruahDepartment of Radiodiagnosis, PGIMER and RML Hospital,New Delhi 110001, Indiae-mail: smitadhingra@yahoo.co.in

Indian J PediatrDOI 10.1007/s12098-012-0878-6

Classically kernicterus has been described in neonateswith bilirubin levels >20 mg/dl. However, preterm infantscan develop kernicterus even in the absence of markedhyperbilirubinemia or acute neurologic symptoms, as wasseen in the index patient. Evaluation of patients with athe-toid palsy should include MRI brain and BAEP irrespectiveof the neonatal bilirubin levels.

References

1. Martich-Kriss V, Kollias SS, Ball Jr WS. MR findings in kernicte-rus. Am J Neuroradiol. 1995;16:819–21.

2. Govaert P, Lequin M, Swarte R, et al. Changes in globus palliduswith (Pre) term kernicterus. Pediatrics. 2003;112:1256–63.

3. AlOtaibi SF, Blaser S, MacGregor DL. Neurological complicationsof kernicterus. Can J Neurol Sci. 2005;32:311–5.

4. Sugama S, Soeda A, Eto Y. Magnetic resonance imaging in threechildren with kernicterus. Pediatr Neurol. 2001;25:328–31.

5. Okumura A, Kidokoro H, Shoji H, et al. Kernicterus in preterminfants. Pediatrics. 2009;123:e1052–8.

Fig. 2 Axial T2 weighted image also reveals the symmetric hyperinten-sity in bilateral globus pallidus (arrows) and mild ventricular dilatation

Indian J Pediatr