menigitis & encephalitis ppt
TRANSCRIPT
Meningitis and Encephalitis
Meningitis
Definition: > Meningitis is an inflammation of the
protective membranes covering the brain and spinal cord, known collectively as the meninges.
> The inflammation may be caused by infection with viruses, bacteria, fungus and less commonly by certain drugs.
Viral Etiologies
Septic Meningitis: common causesAge Causes
Neonates Group B Streptococci, Escherichia coli, Listeria monocytogenes
Infants Neisseria meningitidis, Haemophilus influenzae, Streptococcus pneumoniae
Children N. meningitidis, S. pneumoniae
Adults S. pneumoniae, N. meningitidis, Mycobacteria, Cryptococci
Cerebral shunt Extraventricular drain
Risk Factors
In these cases, infections with staphylococci as well as by pseudomonas
Risk Factor
Children younger than age 5
Risk Factors
Risk Factors:
Pregnancy Working with animals
Compromised immune system
Risk Factors:
diabetes mellitus
Genetic predisposition Environmental or viral stressor Destruction of alpha and beta cells of the
pancreas
Pancreatic transplantation
Failure to produce insulin Production of excess glucagon
Production of glucose from protein and fat stores
Wasting of lean body mass
Chronic elevations in blood glucose levels
Increased ketones
Acidosis
Fatigue
Weight loss
Acetone breath odorIncreased osmolarity
due to glucose
Elevated blood glucose level
Polydipsia Polyuria Polyphagia
Weight lossSmall-vessel disease Accelerated atherosclerosis Impaired immune function
Diabetic retinopathy Diabetic nephropathy Diabetic retinopathy Infection Delayed wound healing
Dialysis, transplantation
End- stage renal failureLaser
therapy
Hypertension Coronary artery disease
Increased low-density lipoprotein
levels
Loss of vision, blindness
Symmetrical loss of sensation
Numbness and tingling in the extremities
Wasting of intrinsic muscles
Charcot’s joint (neopathic joint
disease)
Autonomic neuropathy
Diabetic and foot ulceration
Insulin, meal planning, exercise
Key: = treatment
Pathophysiology
Bacteria reach the meninges through:
bloodstream direct contact between the meninges either through the nasal cavity or the skin.
Bacterial Meningitis
• Mechanism of invasion is not completely understood.
• Host defense mechanism within the CSF are often ineffective.
• Bacterial proliferation stimulates a convergence of leukocytes into the CSF.
• Meningeal and subarachnoid space inflammation release of cytokines into the CSF ( TNF, interleukin 1,6 )
Infectious agent enters Blood circulation
Meningeal vessels become
Hyperemic-Permiable
Neutrophils migrate into SAS
Induce a meningealinflammatory reaction
Fever, chillsTachycardia
Produce exudates and thickens the CSF
IICP Meningeal irritation
Hydroce-phalus Seizures
Choroid plexus/Altered BBB
Headache, vomiting,
papilledema
Macewen’s sign
+ Kernig’s /+ Brudzinski’s Sign
Interferes CSF flow
Inflammation brain parenchyma
Complication of Bacterial meningitis
immediate
Complication of Bacterial meningitis
Delayed
Seizure disorder
Focal paralysis
Subdural effusion
Hydrocephalus
Intellectual deficitsSNHL
Ataxia
Blindness
Bilateral adrenal hemorrhage
Death
Encephalitis
Encephalitis
• Inflammation of the brain parenchyma, presents as diffuse and/or focal neuropsychological dysfunction
• Most commonly a viral infection with parenchymal damage varying from mild to profound.
Etiology-encephalitis
• Arboviruses and herpes simplex virus, are the most common causes of endemic and sporadic cases of encephalitis, respectively.
• Varicella, herpes zoster and Epstein-Barr virus - cause of encephalitis in immunocompromised hosts.
• Severe and Fatal Encephalitis-Arthropod-borne viruses and HSV.
Viral replication
• Hematogenous spread to CNS• Retrograde transmission along neuronal axon• Direct invasion of the subarachnoid space
through infection in the olfactory submucosa
Vectors and Reservoirs
>> Humans are the reservoir for enteroviruses, mumps, measles, herpes simplex, and varicella viruses.
>> H. capsulatum and C. neoformans are organisms found in soil contaminated with bird droppings.
>> Cats are the definitive host for T. gondii; they acquire the parasite from eating infected rodents or other infected meat.
>> Monkeys are the reservoir for simian B virus (cercopithecine herpesvirus 1).
Vectors and Reservoirs
Modes of Transmission>> Enteroviruses: transmitted from person to
person -through ingestion of materials
contaminated by the feces of an infected person
- through exposure to infectious respiratory droplets
- indirectly via fomites>> Some causes of encephalitis, such as Listeria
sp. and T. gondii, may be acquired through consumption of contaminated food.
>> Measles and varicella viruses are transmitted from person to person through airborne route.
>> Simian B disease is transmitted to humans: - through monkey bites - exposure of naked skin or mucous
membranes to infectious monkey saliva or monkey tissue culture
Modes of Transmission
Pathophysiology Encephalitis & Meningitis
Click
Kernig’s Sign of Meningitis:
* Pathogenesis: Meningeal irritation.
Brudzinski Sign
* Pathogenesis: Meningeal irritation.
Neck Stiffness (nuchal rigidity)
* Pathogenesis: Meningeal irritation.
COMPLICATIONS
IICP
Hydrocephahus
Seizures
Diagnostic Strategies
Brain Abscess: CT Scan
Ring enhancement.Surrounding area of inflammation & edema
Hydrocephalus:
Diagnostic Strategies
Lumbar Puncture
Contraindication • Presence of infection on the skin or
soft tissues at the puncture site.• Likelihood of brain herniation.
Contraindication • Present of infection in the skin, soft
tissue at the puncture site.• Likelihood of brain herniation.
Lumbar PunctureIndication for CT scan before LP in suspected Bacterial meningitis
• Immunocompromised state
• History of Stroke
Mass lesionFocal infectionHead trauma
• Seizure occuring 7 days prior
• Abnormal level of consciousness
• Inability to answer questions or follow command
• Abnormal visual fields or paresis of gaze
• Focal weakness• Abnormal speech
CSF Analysis
Opening pressure- 50-200 mmH2O- Lateral recumbent position and sitting position may increase it several fold.- Elevated in bacterial, TB, fungal infections- Falsely elevated in tense and obese patients or when there is marked muscle contraction.
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Nursing Diagnoses
1. Acute pain r/t stimulation of free nerve endings.
2. Ineffective cerebral tissue perfusion r/t increased intracranial pressure.