Herpes Simplex virus infection in CNS ... in CNS Herpe

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The Diagnosis of Nervous System Infections in
Pediatric Cancer Patients

• Hadir Ahmed El-Mahallawy
• Clinical Pathology Department

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Infections of CNS in Pediatric Cancer Patients

• Although rare but awareness of the disease is
  particularly important because
• It usually manifests as an indolent process
• Are usually caused by organisms different from
  those found in the general population
• A significant source of morbidity and mortality

42 to 77
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Infections of CNS in Pediatric Cancer Patients

• Shunt and reservoir infections Children with
  intraventricular shunts and reservoirs are at
  highest risk for CNS inf.
• Meningitis signs of meningeal irritation fever,
  headache and nuchal rigidity altered mental
  status are the most consistent signs at
  presentation.
• Encephalitis commonly present with fever,
  mental status changes (confusion may progress to
  stupor and finally coma), focal neurologic
  signs

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Causes of CNS Infections CNS in Pediatric Cancer
Patients

• BACTERIAL causes
• Whereas the pneumococcus, meningococcus or
  Hemophilus influenza are responsible for 75 of
  cases of bacterial meningitis in patients with no
  underlying disease, the causal organism differ
  widely in impaired hosts.

Gram positive AHS Enterococci Listeria Gram
negative E. Coli K. Pneumoniae Ps.
aeruginosa Mycobacteria
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Causes of CNS Infections CNS in Pediatric Cancer
Patients (cont.)

• VIRAL CAUSES
• HSV
• VZV
• CMV
• HHV-6
• EBV
• MEASLES
• MUMPS

• FUNGAL CAUSES
• Cryptococcus neoformans
• Aspergillus
• C. albicans
• Mucor
• Others
• Toxoplasma gondii

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Differential Diagnosis

• For the cancer patients with focal neurologic
  deficits or altered mentation, it is important to
  separate
• INFECTIONS
• METABOLIC
• TOXIC
• AND
  NEOPLASTIC CAUSES

LEUKEMIA LYMPHOMA
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The Lab. Diagnosis of Nervous System Infections
in Pediatric Cancer Patients

• Sample inspection
• Cell count
• Leishman stain for blasts
• Gram and acid fast stains
• Chemistry Protein levels
• Glucose
• Culture for bacteria, fungi and viral
  cultures

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The Lab. Diagnosis of Nervous System Infections
in Pediatric Cancer Patients (cont.)

• Specific Tests to Identify the Opprtunistic
  Pathogen
• Antigen detection
• Genome detection
• Antibody detection

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Herpes Simplex virus infection in CNS

• Viral infections are mainly seen in patients with
  T- lymphocyte defects.
• Patients develop acute or subacute onset of
  headache, fever, alteration in personality or
  behavioral changes progressing over hours or
  days.
• More slowly evolving disease may be seen in
  immunocompromised hosts
• Olfactory system is characteristically involved

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Diagnosis of Herpes virus infection in CNS

• The affected tissue undergoes marked tissue
  necrosis combined with an inflammatory reaction
  in the perivascular space in the brain
  parenchyma.
• Initial CSF findings may be normal.
• CSF count typically contains 20- 200 cells
• CSF protein is usually elevated 50-200mg/dl
• CSF glucose is usually normal

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Diagnosis of HSV Encephalitis
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Diagnosis of Herpes virus infection in CNS (cont.)

• Brain biopsy was considered the gold standard

With the development of both MRI scanning and
newer lab. Methods PCR and Antigen studies in
CSF, the need for brain biopsy in patients with
suspected HSV has been greatly reduced.
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The NCI Experience in CNS Herpes simplex
encephalitis

• In 2 years (2001 and 2002)
• 40 cases of clinically suspected CNS INFECTIONS
  in pediatric practice
• 12 (30) were laboratory documented to be HSV
  positive.
• HSV encephalitis was found to be the commonest
  cause of CNS inf. at NCI.

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CONCLUSIONS

• Minimal findings of headache, and fever in a
  compromised host should elicit a search to
  exclude possible CNS infection.

• Clinically suspected Herpes simplex virus and
  Varicella Zoster virus encephalitis should
  quickly lead to iv treatment with acyclovir.

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