Bacterial meningits Flashcards
What is meningitis?
Refers to inflammation of the meninges.
Meninges consists of of three layers: the dura mater, arachnoid mater, and pia mater.
Causes can be infective or non-infective.
Infective causes of meningitis?
Bacterial:
Streptococcus pneumoniae
Neisseria meningitidis
Haemophilus influenzae
Listeria monocytogenes
Viral:
Enteroviruses
Herpes viruses (HSV2, HSV1)
Paramyxovirus, measles and rubella viruses
Varicella Zoster Virus
Arboviruses, Rabies virus
Fungal:
Cryptococcus neoformans (affects the immunosuppressed population)
Parasitic:
Amoeba
Toxoplasma gondii
Non-infective causes of meningits?
Malignancies (leukemia, lymphoma, and other tumors)
Chemical meningitis
Drugs (NSAIDs and trimethoprim)
Systemic inflammatory diseases (sarcoidosis, SLE, Behcet’s disease)
Presentation of meningitis?
Headache
Fever
Neck stiffness
Photophobia
Nausea and vomiting
Focal neurology
Seizures
Reduced conscious level
Features of overwhelming sepsis:,
- non-blanching petechial rash [indicative of impending Disseminated Intravascular Coagulation (DIC)]
Signs of meningeal irritation (not specific to meningitis)
- Kernig’s sign (+ve if patient experiences pain and resistance to knee extension, especially when attempting to straighten the leg)
- Brudzinski’s sign (+ve if patient involuntarily flexes their hips and knees in response to neck flexion)
IVx of meningitis?
Bloods (FBC, U&Es, clotting, glucose)
Arterial Blood Gas
Blood cultures
Imaging: CT Head
Lumbar puncture
CSF analysis features of bacterial meningitis?
May be clear or turbid
100-200 PMNs
Culture results positive (may be -ve depending on how heavily infected the meninges are)
Protein raised (due to bacterial protein contamination)
Low glucose (bacteria uses glucose as energy source)
CSF analysis features of aseptic meningitis?
Clearly or slightly turbid (15-500x109 lymphocytes)
Negative culture results
Protein 0.5-1g/l
Normal glucose
CSF analysis features of tubercular meningitis?
Clear or slightly turbid
Fibrin web may develop
30-500x109 lymphocytes plus PMNs
Negative gram stain (need Auramine staining)
Protein 1-6g/L
Glucose 0-2.2
CSF analysis features of crytococcal meningitis?
Opening pressure is very high (poor prognostic sign)
Can have any findings as seen in other CSF results.
Consider in HIV or immunocompromised pt.
Cryptococcal antigen testing or India Ink staining
Management of meningitis?
Suspect bacterial meningitis:
- 2g of IV ceftriaxone BD
- IV amoxicillin
Suspect viral encephalitis:
- IV aciclovir (penicillin allergy, offer chloramphenicol)
Complications
Septic shock
Disseminated Intravascular Coagulation
Coma
Subdural effusions
Syndrome of inappropriate antidiuretic hormone secretion
Seizures
Delayed complications: Hearing loss, cranial nerve dysfunction, hydrocephalus, intellectual deficits, ataxia, blindness
Death
