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Topic review

Topic review. Meningitis. Definitions. Meningitis – inflammation of the meninges Encephalitis – inflammation of the brain parenchyma Meningoencephalitis – inflammation of brain + meninges. Definitions. Meningitis is a clinical syndrome characterized by inflammation of the meninges

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Topic review

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  1. Topic review Meningitis

  2. Definitions • Meningitis – inflammation of the meninges • Encephalitis – inflammation of the brain parenchyma • Meningoencephalitis – inflammation of brain + meninges

  3. Definitions • Meningitis is a clinical syndrome characterized by inflammation of the meninges • There are numerous infectious and noninfectious causes of meningitis (common noninfectious causes eg, medications and carcinomatosis) • may be classified as acute or chronic • Acute meningitis -hours to several days • Chronic meningitis -at least 4 weeks.

  4. Classification • 1. acute bacterial meningitis • 2.acute aseptic meningitis • 3.chronic meningitis • 4. other (depend on specific pathogen); fungal meningitis, parasitic meningitis i.e

  5. Pathophysiology Three major pathways which an infectious agent gains access to the CNS and causes meningeal disease • Hematogenous (eg, from bacteremia, viremia, fungemia) • Retrograde neuronal pathway (eg, Naegleria fowleri, rabies, HSV, VZV) • Direct contiguous spread (eg, sinusitis, otitis media, congenital malformations, trauma, direct inoculation during intracranial manipulation)

  6. Clinical manifestation • Fever , malaise • Headache • nausea, vomiting • photophobia • Hyperirritability • neck stiffness • changes in mental status • Seizure occur in approximately 30% of patients

  7. Clinical manifestation • meningeal irritation sign • Nuchal rigidity, Kernig-, Brudzinsky signs,

  8. Clinical manifestation • Sign of increase ICP • Papilledema • Cushing’s triad • Bradycardia • Hypertension • Irregular respiration • Changes in pupils • LR palsy • Focal neurological deficit

  9. Clinical manifestation • Atypical presentation may be observed in certain groups • Elderly, especially with underlying comorbidities (eg, diabetes, renal and liver disease), may present with lethargy and an absence of meningeal symptoms. • Patients with neutropenia may present with subtle symptoms of meningeal irritation. • Other ; immunocompromised hosts, including organ and tissue transplant recipients and patients with HIV and AIDS • patients with aseptic meningitis syndrome usually appear clinically nontoxic with no vascular instability.

  10. Clinical manifestation • sexual contact and high-risk behavior: HSV meningitis is associated with primary genital HSV infection and HIV infection • exposure to a patient with a similar illness is an important epidemiological clue when determining etiology (eg, meningococcemia). • intake of unpasteurized milk predisposes to brucellosis and L monocytogenes infection. • Animal contacts rabies (LCM) virus Leptospira • History of neurosurgery eg, ventriculoperitoneal shunt cochlear implants

  11. Clinical manifestation • Sinusitis or otitis suggests direct extension into the meninges, usually with S pneumoniae and H influenzae • Rhinorrhea or otorrhea suggests a CSF leak from a basilar skull fracture, with meningitis most commonly caused by S pneumoniae. • petechiae are seen in meningococcal disease with or without meningitis • The presence of a murmur suggests infective endocarditis with secondary bacterial seeding of the meninges

  12. Clinical manifestation • Hepatosplenomegaly and lymphadenopathy suggest a systemic disease, including viral (eg, mononucleosislike syndrome in EBV, CMV, and HIV) and fungal (eg, disseminated histoplasmosis) disease. • Vesicular lesions in a dermatomal distribution suggest varicella-zoster virus. Genital vesicles suggest HSV-2 meningitis

  13. Acute bacterial meningitis • the widespread use of HIB vaccine has decreased the incidence of HIB meningitis by more than 90% the median age of patients shifting from younger than 2 years to 25 years

  14. Acute bacterial meningitis

  15. Acute bacterial meningitis

  16. S. pneumoniae • gram-positive cocci, colonize at human nasopharynx. • most common bacterial cause of meningitis, accounting for 47% of cases with mortality rates 19-26% • Mechanism: hematogenous or direct extension from sinusitis or otitis media • Risk factor • basilar skull fracture and CSF leak. • Patients with hyposplenism or splenectomy • hypogammaglobulinemia, multiple myeloma • glucocorticoid treatment • diabetes mellitus, renal insufficiency, alcoholism, malnutrition, and chronic liver disease

  17. N. meningitidis • gram-negative diplococci that is carried in the nasopharynx (10-15%) • leading cause of bacterial meningitis in children and young adults, accounting for 59% of cases • Meningococcal disease: purulent conjunctivitis, septic arthritis, sepsis +/- meningitis • Risk factors: • household crowding ,college dormitories , military facilities • chronic medical illness • corticosteroid use

  18. N. meningitidis

  19. H. influenzae • small, pleomorphic, gram-negative coccobacilli • frequently found as normal flora in the upper respiratory tract of humans • can spread by airborne droplets or direct contact with secretions • Meningitis is caused by the encapsulated type B strain • It primarily affects infants younger than 2 years. Its isolation in adults suggests the presence of an underlying medical disorder, including sinusitis, otitis media, alcoholism, CSF leak following head trauma, hyposplenism and hypogammaglobulinemia • .

  20. L. monocytogenes • small gram-positive bacillus • one of the highest mortality rates (22%). • Most human cases appear food-borne: coleslaw, milk, cheese i.e • Risk factor: • infants and children, elderly (>60 y) • pregnant women • Alcoholism • Patients with CMI defect • immunocompromised

  21. Aseptic meningitis syndrome • most common infectious syndrome affecting the CNS • acute onset of meningeal symptoms, fever, and cerebrospinal pleocytosis (usually prominently lymphocytic) with negative bacterial microbiologic data • Most episodes are caused by a viral pathogen but they can also be caused by bacteria, fungi, or parasites

  22. Aseptic meningitis syndrome Virus • HERPES (HSV, HZV, EBV, CMV), • ENTERO (Echo,Coxakie,Polio,Enterovirus 68-71 etc.) • ARBO (JEV, Tick-bite encephalitis virus) • Adenovirus • LCMV • HIV • Rabies virus • Mump ,Measles

  23. Aseptic meningitis syndrome • VZV and CMV • causes meningitis in immunocompromised hosts, especially AIDS and transplant recipients • Lymphocytic choriomeningitis virus(LCMV) • transmit by aerosols and direct contact with rodents. • may be associated with orchitis, arthritis, myocarditis, and alopecia. • HIV • Aseptic meningitis may be the presenting symptom in a patient with acute HIV infection. This usually is part of the mononucleosislike acute seroconversion phenomenon. • Mump • Meningitis usually follows the onset of parotitis, which clinically resolves in 7-10 days

  24. Aseptic meningitis syndrome • Bacteria • Partially-treated bacterial meningitis • L monocytogenes • Brucella species • Rickettsia rickettsii • Ehrlichia species • Mycoplasma pneumoniae • B burgdorferi • Treponema pallidum • Leptospira species • Mycobacterium tuberculosis • Nocardia species

  25. Aseptic meningitis syndrome • Parasites • N fowleri • Acanthamoeba species • Balamuthia species • Angiostrongylus cantonensis • G spinigerum • Baylisascaris procyonis • S stercoralis • Taenia solium (cysticercosis)

  26. Aseptic meningitis syndrome • Fungi • Cryptococcus neoformans • C immitis • B dermatitidis • H capsulatum • Candida species • Aspergillus species

  27. Chronic meningitis • constellation of signs and symptoms of meningeal irritation associated with CSF pleocytosis that persists for longer than 4 weeks.

  28. Chronic meningitis

  29. Tuberculous meningitis • acid-fast bacilli  • spread through airborne, droplet     • The presentation may be acute, but the classic presentation is subacute and spans weeks • Patients generally have a prodrome of fever of varying degrees, malaise, and intermittent headaches • Patients often develop central nerve palsies (III, IV, V, VI, and VII), suggesting basilar meningeal involvement 

  30. Tuberculous meningitis • clinical staging of meningeal tuberculosis is based on neurologic status • Stage 1 - no change in mental function with no deficits and no hydrocephalus • Stage 2 - confusion and evidence of neurologic deficit • Stage 3 - stupor and lethargy Always consider tuberculous meningitis in the differential diagnoses of patients with aseptic meningitis or chronic meningitis syndromes

  31. Spirochetal meningitis • T pallidum • modes of transmission: • sexual contact • direct contact with an active lesion • passage through the placenta • blood transfusion (rare) • Three stages of disease are described, and involvement of the CNS can occur during any of these stages. • Syphilitic meningitis usually occurs during the primary or secondary stage. Its presentation is similar to other agents of aseptic meningitis

  32. Spirochetal meningitis • Other CNS syphilitic syndromes include • meningovascular syphilis • parenchymatous neurosyphilis • gummatous neurosyphilis and the symptoms are dominated by focal syphilitic arteritis (ie, focal neurologic symptoms associated with signs of meningeal irritation)

  33. Fungal meningitis C. neoformans • an encapsulated yeast-like fungus that found in high concentrations in aged pigeon droppings   • 50-80% of cases occur in immunocompromised hosts • The infection is characterized by the gradual onset of symptoms, the most common of which is headache.  • The onset may be acute, especially among patients with AIDS

  34. Parasitic meningitis Free-living amoebas (ie, Acanthamoeba, Balamuthia,Naegleria) • infrequent but often life-threatening illness • N fowleriis the agent of primary amebic meningoencephalitis (PAM) • Infection occurs when swimming or playing in the contaminated water • invade the CNS through the nasal mucosa and cribriform plate. 

  35. Parasitic meningitis • PAM occurs in 2 forms. • an acute onset of high fever, photophobia, headache, and change in mental status, similar to bacterial meningitis with involvement of the olfactory nerves sensation. Death occurs in 3 days in patients who are not treated. • subacute or chronic form, is an insidious onset of low-grade fever, headache, and focal neurologic signs. Acanthamoeba and Balamuthia cause granulomatous amebic encephalitis, which spreads hematogenously from the primary site of infection (skin or lungs)

  36. Helminthiceosinophilic meningitis • A cantonensis • cause eosinophilic meningitis (pleocytosis with >10% eosinophils) • acquire the infection by ingesting raw mollusks. • present with nonspecific and self-limited abdominal pain caused by larval migration into the bowel wall. • On rare occasions, the larva can migrate into the CNS and cause eosinophilic meningitis • G spinigerum • cause eosinophilic meningoencephalitis • acquire the infection following ingestion of undercooked infected fish and poultry.

  37. Differential diagnosis • Encephalitis • Brain Abscess • Noninfectious meningitis, including medication-induced meningeal inflammation • Meningeal carcinomatosis • Stroke • CNS vasculitis

  38. Lumbar puncture • Lumbar puncture for CSF examination is urgently warranted in individuals in whom meningitis is clinically suspected • CSF for • Chemistry (glucose & protein) • cell count & diff • Gram stain ,AFB stain • Culture for pathogens • Other : India ink ,serology ,PCR ,Ag Identification ,cytology i.e

  39. Lumbar puncture Between L3-L4(iliac crest level) or L4-L5

  40. Lumbar puncture • Contraindications: • increase risk of herniation(suspected space occupying lesion in CNS) • Skin & soft tissue infection at area of tap • Bleeding disorder • Respiratory distress (positioning) • Complications • Cerebral herniation • Postdural puncture headache • Traumatic tap ,Spinal trauma

  41. Laboratory investigation • CBC • BS • Anti-HIV • H/C • cultures from other possible sites of infection

  42. Imaging study CT or MRI of the brain • indicated in patients with • focal neurologic deficit • increased ICP • suspicious for space-occupying lesions • suspected basilar fracture • diagnosis is unclear • Helpful in the detection of CNS complications of bacterial meningitis, such as hydrocephalus, cerebral infarct, brain abscess, subdural empyema, and venous sinus thrombosis

  43. Treatment : Bacterial meningitis • Bacterial meningitis is a neurological emergency that is associated with significant morbidity and mortality. The initiation of empiric antibacterial therapy is therefore essential for better outcome • usually based on the known predisposing factors and/or initial CSF Gram-stain results. • delays in instituting antimicrobial treatment in individuals with bacterial meningitis could lead to significant morbidity and mortality

  44. Treatment : Bacterial meningitis • penicillins, certain cephalosporins (ie, third- and fourth-generation cephalosporins), the carbapenems, fluoroquinolones, and rifampin provide high CSF levels • Once the pathogen has been identified and antimicrobial susceptibilities determined, the antibiotics may be modified for optimal targetted treatment

  45. Recommended Empiric Antibiotics According to Predisposing Factors for Patients With Suspected Bacterial Meningitis

  46. Recommended Empiric Antibiotics for Patients With Suspected Bacterial Meningitis and Known CSF Gram Stain Results

  47. Specific Antibiotics and Duration of Therapy for Patients With Acute Bacterial Meningitis

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