Th01L02 Meningitis

Th01L02 Meningitis

1. Pathology

   • Common causes investigate with gram stain
     • Listeria (+)
     • Pneumococcus (-)
     • Neisseria (-)
     • Herpes simplex virus
     • Spectrum of colonisation
       • Gram positive bacteria that invade neutrophils
         • Endotoxins = inflammatory response o Widespread vasodilation > CV shock
           • Myocardial damage > septic shock
             • Intravascular coagulation > blocked blood vessels
               • Vessel damage - haemorrhage into tissues (e.g. petechial rash
                 • Basically, disruption of normal CV system physiology and its role in delivering oxygen nutrients to tissues
       • Evidence usually picked up by CSF but in this case using Polymerase Chain Reaction to ID DNA of meningococcus
         • Uusually evidence of septicaemia
   • Lab work
     • Polymerase chain reaction for DNA detection
     • High RBC count (610/ cu mm) - normal <5
     • High WBC count (4000 cells/cu mm) - normal <5 o 2% lymphocytes, 98% polymorphs
     • Low BGL (0.9 mmol/L) - normal 5.8
     • High protein levels (5359g/L) - normal 150-400
     • Clotting high (>6.0g/L) - normal 1.5-4.5

2. Immediate managment

   • Penicillin from GP according to NICE guidelines
     • First line of defence&nbsp;
     • Erythromyocin is used for pneumoccus too esp. with penicillin allergies
   • Empiric antibodies for suspected pneumococcus
     • e.g. IV Ceftiaxone
   • Anti-viral e.g. Aciclovir
     • for suspected viral encephalitis
   • Corticosteroid e.g. Dexamethasone
     • Rare, only used in some cases

3. Physical signs and symptoms

   • Drowsy, unrousable
     • Glasgow coma score 7/15
   • Small haemorrhagic lesion on foot
     • Evidence of septicaemia
       • &nbsp;blood poisoning/ toxicity resulting in&nbsp;deranged blood clotting and rash &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
       • Evident in advanced cases but less obvious early on
       • Signs and symptoms
         • Headache, nausea, vomiting
         • Photophobia
         • Stiff neck
         • Non-blanching rash
     • These 'spots' are a well-publicised feature of meningococcal infections
       • Glass test check if the spots are blanching vs. non-blanching
   • Dialated temporal horns
     • Possible evidence of cerebral oedema
   • Prodrome phase in self-limiting viral illness
     • Lasts up to 4 hours in young children
     • Lasts up to 8 hours in adolescents
   • Symptoms from hours of onset (RED FLAG symptoms)
     • Fever earliest symptom across ages and most common
     • Sepsis features second earliest symptom and most common
     • Impaired mental status, meningism and haemorrhagic rash takes longer across ages and develops slower (also occurs in less people)
     • Importance
       • Identifying these could reduce proportion of missed cases in first consultation by half
         • Recognising symptoms after 19 hours of onset, brings prognosis forward 11 hours
   • Long term
     • Gangrene due to obstructed circulation
     • Severe septicaemia

4. Public health importance

   • Public health (CCDC) needs to be notified
     • &nbsp; &nbsp; &nbsp;&nbsp; Pt must have picked up bacteria from close contact&nbsp; Bacteria often &nbsp;colonises throat but in this case &nbsp; &nbsp;
     • Type A
       • Meningitis type A (Meningitis belt) of Africa, type B not so common Africa
       • Type A found in Asia far more than other types
   • Responsibilities of public health officials
     • Follow up family o Follow up staff who performed intubation of pt. in A&E (low risk but need to be given antibiotic cover) o Follow in flat or halls - need to consider flatmates and any possible close contacts:
   • Type B
     • rates of type B quite steady from 1999-2009
     • Type B far more common 2005-2015 in England vs. type C, Y and other regardless of age
     • Type B most common in children age 1-4, then <1, and then 15-19 years
   • New vaccine!
     • In infants born since 01 July 2015 o Type C particularly used to be in teenagers/students but vaccine now o New this month, meningococcus type ACWY vaccine in adolescents

5. Prevention

   • Friends and relatives
     • Parents need to get their children vaccinated A+C, ACYW or C- conjugate, B
     • Contact tracing and giving antibiotic prophylaxis for close contacts
     • Surveillance and notifiable disease reporting

6. Meninges are the three membranes (the dura mater, arachnoid, and pia mater) that line the skull and vertebral canal and enclose the brain and spinal

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