Infectious Disorders and Neoplasms of CNS Flashcards
1
Q
Describe meningitis
A
- Inflammation of the meninges of brain & spinal cord secondary to infection
- Needs to be treated quickly
- Inflammation can extend to 1st & 2nd layers of cortex & spinal cord
- Increased chance of tissue infarction, scar tissue formation, which can restrict CSF flow, resulting in hydrocephalus
- Stretch & pressure on meninges can cause the cardinal sign: headache
2
Q
Pathogenesis of meninges
A
- Bacterial & viral infections: Pneumonia, Influenza, Meningococcus, Tuberculosis, Enterviruses, Herpes virus
- Pathogens invade host mucosal epithelium, multiply in blood stream & cross BBB into CSF
- CSF offer much less immunity from pathogens due to lack of immune cells
- Besides inflammation of meninges, neuronal cell death can occur through apoptosis & necrosis
- White matter injury also occurs secondary to small vessel vasculitis, venous thrombosis & focal ischemia
3
Q
Clinical manifestations of meningitis
A
- Primary signs: headache, sudden high fever, stiff neck
- Other signs: altered mental status, vomiting, focal deficits, loss of appetite, sensitivity to light
- Positive meningeal signs: Nuchal rigidity, Kernig’s sign, Brudzinski’s sign
- In severe cases: opisthotonus, seizures, reduced level of consciousness
4
Q
How to diagnose meningitis
A
- Lumbar puncture for culture to determine the type of organism involved
- CT or MRI
- Time course of onset indicates type of organism
- Viral meningitis can develop in hrs and bacterial can take 1-2 days
- Gram staining of bacterial cells for. faster diagnosis of. bacterial meningitis
5
Q
Treatment of meningitis
A
- Treated promptly with antibiotics that can cross BBB
- Steroids like dexamethasone to reduce inflammation
- Viral meningitis is symptomatic
- Prognosis of. viral meningitis is excellent, most individuals recover in 1-2 wks
6
Q
Describe encephalitis
A
- Acute inflammatory disease of the brain parenchyma caused. by direct viral/bacterial invasion or by hypersensitivity initiated by virus
- Inflammation primarily in gray matter of CNS
- Viruses. carried by mosquitoes & ticks are responsible
7
Q
Causative viruses of encephalitis
A
- West nile virus
- Herpes simplex
- Mycoplasma
- Protozoa
- Complication from bacterial meningitis
8
Q
Clinical manifestations of encephalitis
A
- Sx depend on etiologic agent & brain area involved
- Fever, headache, n/v followed by altered mental status (lethargy, confusion, memory disturbances), seizures
- May be focal signs, hemiparesis, aphasia, sensory deficits, ataxia, chorea, athetosis
- Infants: irritability, poor appetite
- Meningeal irritation can cause stiff back, neck
9
Q
Clinical manifestations of encephalitis from west nile virus
A
- Fever
- Headache
- Stiff neck
- Photophobia
- Lesion of anterior horn cells cause paralysis & diminished reflexes
10
Q
Clinical manifestations of encephalitis from herpes simplex
A
- Seizures
- Hallucinations
- Memory disturbances
11
Q
Diagnosis and treatment of encephalitis
A
- Dx depends on detection of IgM antibody in serum or CSF, EEG
- MRI better than CT
- Tx depends on infectious agent: Acyclovir improves outcomes from herpes simplex
- Close supervision of Sx is critical
- Prognosis depends on infectious agent, recovery from paralysis is variable, depending on degree of motor neuron involvement
12
Q
Describe primary versus secondary CNS neoplasms
A
- Primary: develop in brain, spinal cord, or surrounding structures; benign or malignant
- Secondary: metastatic; spread to CNS from another site such as lung or breast
13
Q
Describe paraneoplastic syndromes versus leptomeningeal carcinoma
A
- Paraneoplastic: may. occur bc of remote effects or indirect effects on CNS from cancer elsewhere in body
- Leptomeningeal Carcinoma: when cancer metastasizes to pia &. arachnoid with multiple lesions in meninges & CSF pathways
14
Q
Diagnosis and treatment of CNS neoplasms
A
- Dx is devastating to patient & family
- Difficult decisions about treatment options & QOL issues add stress
- Caregiving & financial struggles are. frequently encountered
- Situation is improving with dramatic new advances in radiologic imaging, neurosurgery, adjuvant therapy
- At present ~50% of patients with CNS tumors can be successfully treated & have excellent long term prognosis
15
Q
Effects of CNS neoplasms
A
- Most primary malignant tumors are locally invasive & cause significant morbidity & mortality
- Early effects: displacement of Brian or spinal cord tissue or blockage of CSF circulation causing increased ICP
- Tumor grows -> compression increases -> specific neurologic deficits
- As tumor progresses symptoms of brain tumors may range from minimal (lethargy) to marked (paralysis)
- Primary CNS tumors do not usually metastasize outside CSN due to lack of CNS lymphatic system to transport cancer cells
