Meningitis Flashcards
What is meningitis?
Meningitis is an inflammatory process involving the leptomeninges within the subarachnoid space (CSF)
How can meningitis be classified?
Meningitis can be classified by duration and age.
What are the 3 types of durations in meningitis?
Acute-pyogenic
Aseptic-viral
Chronic- TB, Syphilis, Cryptococcus
What are the causative organisms in each age group of meningitis?
Neonates- Group B Strep, E. coli
Young adults- Neisseria meningitidis
Elderly- Listeria Monocytogenes (Immunocompromised as well), Streptococcus Pneumonia
Classical symptoms of Meningitis
Headache
Fever
Nuchal rigidity
– Nuchal rigidity not present in children <1 y
– Fever and chills
– Photophobia
– Vomiting
– URI symptoms (viral and bacterial)
– Seizures Focal neurologic symptoms
(including focal seizures)
Signs of meningeal irritation
Nuchal rigidity or discomfort on neck flexion
– Kernig sign: Passive knee extension in supine, patient elicits neck pain and hamstring resistance.
– Brudzinski sign: Passive neck or single hip flexion is accompanied by involuntary flexion of both hips.
Papilledema
Focal neurologic signs
– cranial nerve abnormalities III, IV, VI,VII)
What are the normal features of CSF?
Appearance —Clear
Pressure —60-150mm
Cells—0-4
Proteins —15-45 mg/dl
Glucose —50-80 mg/dl
Bacteriology —Sterile
What are the features of CSF in bacterial meningitis?
Appearance — Cloudy
Pressure — >180mm H2O
Cells— 100,000 cu mm
Proteins — Markedly raised
Glucose — Markedly reduced
Bacteriology — Organism+
What are the investigations for bacterial meningitis?
Routine + Spinal tap (CSF analysis)
What is the treatment for bacterial meningitis?
Antibiotics- 3rd generation Cephalosporins
Microscopy of bacterial meningitis
On microscopic examination,………may fill the entire………….space or, in less severe cases, may be confined to regions adjacent to……………… In untreated meningitis,………. reveals varying numbers of the…………..
When the meningitis is………., the organisms and the…………….. may spread into the………………. (focal cerebritis), sometimes leading to the formation of……………
Later,………..&…………..
On microscopic examination, neutrophils may fill the entire subarachnoid space or, in less severe cases, may be confined to regions adjacent to leptomeningeal blood vessels. In untreated meningitis, Gram stain reveals varying numbers of the causative organism.
When the meningitis is fulminant, the organisms and the associated inflammatory cells may spread into the substance of the brain (focal cerebritis), sometimes leading to the formation of abscesses.
Later, fibrosis & hydrocephalous.
What is Aseptic meningitis?
Aseptic meningitis is a clinical term for acute illness with meningeal signs and symptoms that is believed to be of viral origin.
Also, Less fulminant and Self limiting
Causative viruses of Aseptic meningitis.
70% enterovirus
Echovirus
Coxsackievirus
Poliovirus
Varicella
HSV
HIV
Investigations of Aseptic meningitis
Serology and PCR
What are the features of CSF in viral meningitis?
Appearance —- Mild turbid (sediment. moving around)
Pressure — >250mm
Cells— 10-100
Proteins —- Raised
Glucose — Normal
Bacteriology — Sterile
what is chronic meningitis?
Chronic meningitis — one that’s long-lasting — can be caused by slow-growing organisms such as fungi and Mycobacterium tuberculosis.
About Tuberculous meningitis
Most Common pattern - diffuse meningoencephlitis
Microscopy: macro+ lympho+ plasma cells
Florid cases: granulomas
Obliterative endartritis
Organism: acid fast stain
Intraparenchymal tuberculoma
What are the features of CSF in tuberculous meningitis?
Appearance —- Turbid forms coagulum
Pressure — >300mm
Cells— 100-1000
Proteins —- Raised
Glucose — Reduced or normal
Bacteriology — Tubercle bacilli
Rich focus presentations (tuberculous mening.)
Tuberculomas
Arachnoid fibrosis
Hydrocephalus
What is the Cobweb appearance (depending on stage) of TB meningi?
active—- caseation
Inactive—- calcification
Healed—-fibrous
What is the treatment of Tuberculous meningitis?
Isoniazid
Ethambutol
Pyrazinamide
What is Fungal meningitis?
Fungal meningitis can develop after a fungal infection spreads from somewhere else in the body to the brain or spinal cord. Some causes of fungal meningitis include Cryptococcus, Histoplasma, Blastomyces, Coccidioides, and Candida.
Fungal meningitis is also
less common.
rare in healthy people.
more found in people with an impaired immune system- AIDS
In meningitis caused by Cryptococcus neoformans, the CSF..
-May have few cells but elevated protein, and the mucoid encapsulated yeasts can be visualized on India ink preparations.
-Extension into the brain follows vessels in the Virchow Robin spaces.
-As organisms proliferate, these spaces expand, giving rise to a “soap bubble”–like appearance
