Neurologic signs and symptoms such as nuchal rigidity or alteration in consciousness may be indications for imaging. Symptoms in infants may be nonspecific, including fever, poor feeding, irritability, and lethargy. Seizures are not uncommon in these young children, mostly occurring when the inflammation has progressed to involve the brain parenchyma. Older children may have fever, headache, nausea, vomiting, confusion, stiff neck, and photophobia. Symptoms of viral meningitis can resemble those of the flu. An MRI scan of the brain is indicated in patients with signs of intracranial infection with headache. MRI with and without IV contrast is indicated in the evaluation of intracranial infections that include meningitis, encephalitis, and brain abscess. MRI may improve the sensitivity for detecting encephalitis as T2 FLAIR is sensitive for vasogenic edema, diffusion-weighted imaging is sensitive for cytotoxic edema, and postcontrast T1 and T2 FLAIR sequences are sensitive for meningeal enhancement. The combination of MRI sequences can be very helpful to exclude mimics of encephalitis, identify the extent of inflammation, and confirm if lesion distribution is concordant with symptoms [52]. The distribution of abnormalities on MRI can help guide in determining the pathogen in some cases. For instance, brainstem and spinal cord involvement is common with enterovirus, and basal ganglia/thalamic involvement is common with West Nile virus or Japanese encephalitis. It is important to note that the classic limbic distribution of herpes simplex virus-1 may not always be present, and that extratemporal involvement is not uncommon [52]. Extracranial infections, including subdural empyemas (SDE) and epidural empyemas, can also be well evaluated with MRI. Epidural empyemas are collections of suppurative fluid located between the skull and dura.
Headache Child PCAs. Neurologic signs and symptoms such as nuchal rigidity or alteration in consciousness may be indications for imaging. Symptoms in infants may be nonspecific, including fever, poor feeding, irritability, and lethargy. Seizures are not uncommon in these young children, mostly occurring when the inflammation has progressed to involve the brain parenchyma. Older children may have fever, headache, nausea, vomiting, confusion, stiff neck, and photophobia. Symptoms of viral meningitis can resemble those of the flu. An MRI scan of the brain is indicated in patients with signs of intracranial infection with headache. MRI with and without IV contrast is indicated in the evaluation of intracranial infections that include meningitis, encephalitis, and brain abscess. MRI may improve the sensitivity for detecting encephalitis as T2 FLAIR is sensitive for vasogenic edema, diffusion-weighted imaging is sensitive for cytotoxic edema, and postcontrast T1 and T2 FLAIR sequences are sensitive for meningeal enhancement. The combination of MRI sequences can be very helpful to exclude mimics of encephalitis, identify the extent of inflammation, and confirm if lesion distribution is concordant with symptoms [52]. The distribution of abnormalities on MRI can help guide in determining the pathogen in some cases. For instance, brainstem and spinal cord involvement is common with enterovirus, and basal ganglia/thalamic involvement is common with West Nile virus or Japanese encephalitis. It is important to note that the classic limbic distribution of herpes simplex virus-1 may not always be present, and that extratemporal involvement is not uncommon [52]. Extracranial infections, including subdural empyemas (SDE) and epidural empyemas, can also be well evaluated with MRI. Epidural empyemas are collections of suppurative fluid located between the skull and dura.