Chronic Granulomatous HSV Encephalitis: Digeorge Syndrome Case Study

Okay, let’s⁢ break down the facts provided from the text and figures. This case study ⁤details a complex presentation of Herpes Simplex Virus (HSV) encephalitis in a child with an underlying, initially undiagnosed, immunodeficiency. Here’s a summary, focusing on the key findings:

Clinical Presentation & Initial Course:

* The child initially presented with HSV encephalitis.
* Despite treatment, the encephalitis showed an unusually persistent and worsening course, including neuro-regression (deterioration of neurological function).

Imaging Findings (Figures 3 & 4):

* Figure 3 (MRI – 2 months after initial presentation):

* ⁢ Increased⁤ Gliosis: Significant scarring (gliosis) in both frontal lobes, left temporal lobe, and right⁢ parietal-temporal lobes. This indicates brain damage.
* Reduced Enhancement, New Enhancement: While some initial inflammation (enhancement) had decreased, new areas of enhancement appeared within the gliotic regions of the frontal lobes. This suggests ongoing or evolving inflammation.
* Pachymeningeal⁣ Thickening: Thickening of the membranes surrounding the brain (meninges).
* Figure 4‍ (Histopathology & Immunohistochemistry):

* Chronic Inflammation: Brain tissue shows a dense collection of lymphocytes and histiocytes (immune‍ cells), indicating a long-standing inflammatory process.
* Granulomatous Changes: Histiocytic aggregates suggest a granulomatous inflammatory response.
* ‍ HSV Positive Staining: Immunohistochemistry (IHC)⁣ confirmed the presence of Herpes Simplex Virus (HSV) in neurons,⁤ showing viral inclusions and damage (cytopathic changes). This confirms the diagnosis of HSV encephalitis.

Immunodeficiency Examination⁢ & Diagnosis:

* initial immunodeficiency tests (T/B cell counts,⁤ immunoglobulin levels) were normal.
*‍ ⁢ Immunoglobulin functional assay could not be performed.
* Clinical Exome Sequencing (CES): Revealed a heterozygous micro-deletion on chromosome 22, strongly suggesting DiGeorge syndrome (DGS).
* DGS Features:

* The child had a history of recurrent respiratory infections (a common sign of DGS).
* A previous CT scan of the chest (at age 12) showed no thymic shadow (the thymus gland is often⁢ absent or underdeveloped in DGS).
⁢ * Echocardiogram was normal, ruling out cardiac defects.
* No parental consanguinity or symptoms in parents.
* ⁤ Parental genetic testing was not performed.

Key Takeaways:

* This case highlights the importance of considering underlying immunodeficiencies in patients with unusually severe or persistent viral infections, even if initial immune tests are normal.
* digeorge Syndrome can present with subtle or atypical features,and genetic testing (CES) can be crucial for diagnosis.
* The combination of imaging,histopathology,and genetic testing was essential to unravel the complex etiology of this patient’s ⁢illness.

Let me know if you’d like me to ⁤elaborate on any specific aspect of this case, or if you have further questions.