4501 Flashcards
(101 cards)
What is meningitis?
Aninfectious diseaseof the central nervous system that causesinflammationof the meningealmembranes(involving all three layers) surrounding thebrainandspinal cord.
How is meningitis caused?
Bacteria fungi, viruses, autoimmune disorders, cancer/paraneoplasticsyndromes, drug reactions
What are the infectious etiologic agents of meningitis ?
bacteria,viruses,fungi, and less commonlyparasites
Meningitis is defined as what?
as inflammation of the meninges. The meninges are the three membranes (the dura mater, arachnoid mater, and pia mater) that line the vertebral canal and skull enclosing the brain and spinal cord (Encephalitis is inflammation of the brain itself).
Most common cause is?
viral. It usually does not cause serious illness. However, in severe cases, it can cause prolonged fever and seizures
Fungal meningitis typically is associated with?
Immunocompromised host (HIV/AIDS, chronic corticosteroid therapy, and patients with cancer)
Meningococcal meningitis
particular importance due to its potential to cause large epidemics.
Bacteria are transmitted from person-to-person through droplets of respiratory or throat secretions from carriers
The disease can affect anyone of any age, but mainly affects babies, preschool children and young people
Untreated meningococcal meningitis can be fatal in up to 50% of cases and may result in brain damage, hearing loss or disability in 10% to 20% of survivors
Meningitis Pathophysiology
Typically occurs in 2 routes
1. Hematogenous seeding
2. Direct Contiguous Spread
Hematogenous seeding
Bacteria colonize the nasopharynx and enter the bloodstream after the mucosal invasion. Upon making their way to the subarachnoid space, the bacteria cross the blood-brain barrier, causing a direct inflammatory andimmune-mediated reaction.
Direct contiguous spread
Organisms can enter the cerebrospinal fluid (CSF) via neighboring anatomic structures (otitis media, sinusitis), foreign objects (medical devices, penetrating trauma), or during operative procedures.
IMD
characterized by a short incubation period (2 to 10days, usually 3 to 4days) and usually presents as an acute febrile illness with rapid onset and features of meningitis or septicemia (meningococcemia), or both, and a characteristic non-blanching petechial or purpuric rash
Meningococcemia (blood infection)
Bacteria in blood stream, pale or mottled skin, purplish rash, unusually cold hands and feet, breathing fast, breathless, limb, joint, muscle pain.
very sleepy & vacant, high fever, confused & delirious, vomiting.
Meningitis (Spinal Cord/ brain infection)
Sensitivity to bright light, seizures, stiff neck, severe headache.
very sleepy & vacant, high fever, confused & delirious, vomiting.
Meningitis: Clinical Presentation
Most common presenting symptoms: headache, fever, vomiting, and rigidity of the neck
Early symptoms include nausea, drowsiness, and confusion. Pain in the posterior thigh or lumbar region may also be noted
Later symptoms can include seizures, photophobia, and rapid breathing rate.
***Rash on the skin: scanty petechial (red or purple non-blanching macules smaller than 2mm in diameter), or a purpuric (larger than 2mm) appears on approximately 80-90% of individuals with bacterial meningitis.
Can meningitis and septicemia happen together?
Yes often times happen together
Kernig’s sign
knees cannot extent due to pain when hip flexed go 90 degree.
Brudzinski sign
bend neck, hips and flex knees
Meningitis: Diagnosis
Meningitis is diagnosed through cerebrospinal fluid (CSF) analysis, which includes white blood cell count, glucose, protein, culture, and in some cases, polymerase chain reaction (PCR). CSF is obtained via a lumbar puncture (LP), and the opening pressure can be measured.
Additional testing should be performed tailored on suspected etiology.
Viral: Multiplex and specific PCRs; Fungal: CSF fungal culture, India ink stain for Cryptococcus; Mycobacterial: CSF Acid-fast bacilli smear and culture; Syphilis: CSF VDRL; Lyme disease: CSF burgdorferi antibody
Meningitis: LABS
CBC (elevated WBC indicates infection)
Blood culture (+ indicates bloodstream infection)
Urinalysis (infection in urinary tract)
CXR (pulmonary related infection)
Biopsy (may biopsy rash)
CT/MRI (to check for brain tissue swelling/complications)
Antibiotics
Managing the airway, maintaining oxygenation, giving sufficient intravenous fluids while providing fever control are parts of the foundation of meningitis management.
The type of antibiotic is based on the presumed organism causing the infection. The clinician must take into account patient demographics and past medical history in order to provide the best antimicrobial coverage.
Steroid Therapy
Corticosteroids can reduce the inflammation and possibly reduce associated hearing loss and other neurological sequela
Increased intracranial Pressure
If the patient develops clinical signs of increased intracranial pressure (altered mental status, neurologic deficits, non-reactive pupils, bradycardia), interventions to maintain cerebral perfusion include:
Elevating the head of the bed to 30 degrees
Osmoticdiuretics as 25% mannitol or 3% saline)
Chemoprophylaxis
Indicated for close contacts of a patient diagnosed with N. meningitidis and H. influenzae type B meningitis. Close contacts include housemates, significant others, those who have shared utensils, and health care providers in proximity to secretions (providing mouth-to-mouth resuscitation, intubating without a facemask)
Vaccines
Vaccines for the prevention of IMD that are authorized for use in Canada include:
Monovalent conjugate meningococcal vaccines(Men-C-C)
Quadrivalent conjugate meningococcal vaccines(Men-C-ACYW)
Serogroup B meningococcal vaccines
Multicomponent meningococcal serogroup B vaccine (4CMenB)
Bivalent factor-H binding protein meningococcal serogroupB vaccine (MenB-fHBP)
Meningococcal vaccines are initially highly effective but effectiveness wanes over time