PCL Avulsion Fracture
Joseph Junewick, MD FACR
over 6 years ago
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In Utero/Congenital HSV
Heather Borders, MD
|Diagnostic Category: Infectious-Inflammatory
|Created: over 5 years ago
|Updated: over 5 years ago
Term newborn with neurologic symptoms and seizure.
In Utero/Congenital HSV
Complex history with MVA/trauma mid pregnancy and maternal trauma just prior to delivery.
Diffusely markedly abnormal brain. Extensive low density and T1/T2 prolongation in the white matter. Atrophy of the basal ganglia and scattered areas of cortical loss and thinning. Immature sulcation pattern. Mildly enlarged ventricles. High density in the basal ganglia on CT may reflect dystrophic calcification. Ultrasound is not shown, but demonstrated diffuse cystic encephalomalacia and increased echogenicity in the basal ganglia suggesting dystrophic calcification. Imaging findings are compatible with a chronic infection.
Herpes simplex viral infections of the neonate occur with exposure to maternal type 2 herpetic lesions, most commonly during birth. However, while 85% of cases of congenital HSV are acquired during peripartum period, 10% occur antenatally, and 5% occur in utero. The estimated incidence is 1/2000-5000 births per year with approximately 30% involving the central nervous system.
Neurologic symptoms will prompt evaluation and include lethargy, apnea, poor feeding, seizures, bulging of fontanelles. If the infection is acquired in utero, symptoms may also include microcephaly, low birth weight, and micropthalmia. CSF studies reveal pleocytosis, elevated protein, and decrease glucose with a negative gram stain. CSF detection of viral DNA by PCR is diagnostic.
If herpes encephalitis is suspected, CT and MRI are the studies of choice. The earliest changes are often seen on diffusion weighted sequences with reduced diffusion in affected areas. After a few days, patchy low attenuation lesions by CT and increased T2 signal is seen within the white matter. Findings that are more specific for herpes encephalitis include diffuse meningeal enhancement and increased attenuation of the cortical gray matter.
As the disease progresses, there is prominence of the ventricles, development of cysts, and calcium deposition in the basal ganglia, thalami, cortex, and white matter. Hemorrhage is less common in HSV-2 when compared with HSV-1 infections. Sonography is usually nonspecific demonstrating hyperechogenicity with or without ventricular compression. Late sonographic findings include multicystic encephalomalacia and calcium deposition.
The differential diagnosis for the abnormal imaging appearance of the brain in patients with HSV-2 encephalitis includes postnatal infection, other TORCH infections including CMV or toxoplasmosis, and stroke. Prognosis for these newborns is poor when the CNS is involved. The survival rate is 50% with many of the survivors developing mental retardation, severe neurological defects, and seizures.
Barkovich, AJ. Pediatric Neuroimaging, 4th ed. Lipincott Williams & Wilkins; 2005; 807-08.
Jennifer Rollenhagen, MD