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Pyogenic Meningitis
Asso. Prof. Dr.Khin Htwe
ACUTE BACTERIAL MENINGITIS
Pathophysiology of convulsions
• Seizures are paroxysmal manifestations of the electrical properties of the cerebral cortex
• A seizure results when a sudden imbalance occurs between the excitatory and inhibitory forces within the network of cortical neurons in favour of a sudden-onset net excitation
• Impairment of the γ-aminobutyric acid (GABA)–ergic inhibitory system
• Excitatory glutamatergic synapses (excitatory amino acid neurotransmitters glutamate, aspartate)
• Seizures may arise from areas of neuronal death, and these regions of the brain may promote development of novel hyperexcitable synapses that can cause seizures eg temporal lobe lesions can cause seizures
Brain injury – • One suggests that inhibitory neurons are
selectively damaged and remaining principal excitatory neurons become hyperexcitable
• The other hypothesis suggests that aberrant excitatory circuits are formed as part of reorganization after injury
Seizures more common in chhildren
• Underdeveloped brain is more susceptible to specific seizures than is the brain of an older child or adult (age specific – infantile spasm)
• Immature brain is more excitable than the mature brain, reflecting the greater influence of excitatory glutamate-containing circuits
• Actions of GABA, the major inhibitory neurotransmitter, are often paradoxically excitatory in the immature brain
Differential diagnoses of acute onset of fever and fits
• Febrile convulsion• Acute bacterial meningitis• Cerebral malaria• Encephalitis
Meningitis• Inflammation of leptomeninges• Viral infection – commonest, self-
resolving in most cases• Bacterial meningitis – may have
severe consequences
Clinical featuresNewborn - 2 months- Signs and symptoms are not typical
as in older children.• Poor sucking Poor tone• Staring eyes Poor cry• Irritability Drowsiness• Convulsion
• There may be history of • Prematurity LBW• Complicated labour PROM• Maternal sepsis.
Clinical featuresInfants and older children•Preceding history of
• Ear discharge• Head injury• Sinusitis may be present
Signs and Symptoms• Less common - Dramatic onset -
Meningococcal infection may progress rapidly leading to shock, purpura, DIC and reduced level of conciousness and died within 24 hours
• Commonly – several days of fever with URT or GI symptoms followed by non-specific CNS symptoms
• Infants and young children – fever, poor feeding, vomiting, irritability, lethargy, drowsiness, seizures or reduced consciousness
• Older children – fever, Vomiting, headache, photophobia, neck stiffness, drowsiness, convulsion, coma
Signs and Symptoms
• Bulging and tense fontanelle.• Signs of meningeal irritation
• Neck stiffness• Kernig’s sign• Brudzinski’s Sign.
Increased ICP suggested by• Head ache, vomiting, bulging fontanelle or
diastasis (widening ) of sutures• Ocular or abducens nerve paralysis• Hypertension with bradycardia• Apnea or hyperventilation• Decorticate or decerebrate posture• Stupor or coma.• Pappilloedema is uncommon (chronic process).
Meningococcal meningitis
Meningococcemia
• Petaechiae, and/or purpura, or maculopapular
rashes
• Signs of shock may be present.
Organisms causing bacterial meningitis
Neonatal to 3 months - Group B streptococcus
E.coli and other coliforms
Listeria monocytogenes
1 month – 6 year - Nisseria meningitidis
Streptococcus pneumoniae
Haemophilus influenzae
>6 years - Nisseria meningitidis
Streptococcus pneumoniae
• 0-1 month - GBS
E. coli• 1-3 m – GBS, E.coli,
Strep.pneumoniae H.influenzae type b
• >3 mo - N. meningitidis
S. pneumoniae
H. influenzae type b
Acute bacterial meningitis(Causal organisms) (M Protocol)
Investigations for Diagnosis - CSF examination including Gram stain & culture
• CSF Examination• Raised CSF pressure
• Appearance - Turbid or opalescent
• Raised protein
• Increased cell count, may be numerous, mainly
neutrophils
• Reduced sugar
Infection Pressuremm Hg
Leucocytes Total/cumm
Leucocytes (Differ)
Protein g/l
Glucose Mmol/l
Normal 50-80 <5 lymphocytes
0.2-0.4 2.8 - 4.4
Bacterialmeningitis
100-300 100->50,000
PMN 1.0 – 5.0 0.5 – 1.5
TB meningitis
increased 10 - 500 Lymphocytes
1 - 5 0 - 2
CSF Gram Stain
• Results within hours
• Gram (+) cocci, Gram (-) cocci, Gram (-)
coccobacilli or bacilli
CSF Culture & Sensitivity
• 3 to 7 days to get the results
• Organisms identified
CSF Antigen – Latex agglutination test
CSF PCR - organism
Blood
• Culture may identify organisms dose
• FBC – Neutrophil leucocytosis
• Latex agglutination test of blood for antigen
• PCR – organism
• Glucose
Investigations for complications
• BUSE
SIADH - urea level normal
: serum Na level low, high urine Na• Coagulation screen (DIC)• CT/MRI brain scan and EEG
- for hydrocephalus, subdural effusion, brain abscess, cerebral infarct
• Ultrasound for infants - confirm with CT/MRI brain scan
Contraindications to LP
• Cardiorespiratory instability• Focal neurologic signs• Signs of increased ICP
Glasgow coma scale <8
Abnormal dolls’ eye reflex, Unequal pupils
Papilloedema, High BP low HR• Coagulopathy, thrombocytopenia• Local infection at the site of LP• Immediately after recent seizure
Fever and S&S of bacterial meningitis
LP contraindicated
Yes (withhold LP)No(carry out LP)
• do blood,urine
• Start antibiotic
dexamethasoneAbnormal CSF
Continue antibiotic
improvement No improvement
Complete course of treatment
Normal CSF,wait for CSF culture and Latex agglutination
negativepositive
Re-evaluate, consider discontinue antibiotic
Change antibiotic No response- consider TB,fungus or encephalitis
Treatment
• Antibiotics• Dexamethasone• Supportive treatment
• Fluid balance, Fluid restriction• Monitor vital signs and signs of raised ICP, Input and
output• Fit chart• Daily neurological assessment• Measure OFC daily
• Follow up• Prevention
Dexamethasone• Use of steroids – Antiinflammatory to
prevent cytokine release- Best given before or with first
antibiotic dose- Dose: dexamethasone 0.15mg/kg
6hly for 4 days or 0.4mg/kg 12hly for 2 days
Fluid
• Maintanence
• Fluid restriction (2/3 of maintenance)
• Fluid replacement if shock is present
in cases of meningococcal meningitis.
Cerebral monitoring
(Neuro-observation Chart)
Cerebral oedema
• IV 20 % mannitol 7 to 10 ml/kg/20 mins, can be
repeated 8 hourly
Seizure – anticonvulsants
Apnoea – mechanical ventilation
Care of unconscious patient – Nursing, bladder,
bowel, skin.
Complications• Immediate
• Seizures
• Cerebral or cerebellar herniation
• Increase Intracranial pressure
• Cranial nerve palsies
• Subdural effusion
• SIADH
• Hydrocephalus
• Waterhouse Friderichsen syndrome
Complications• Remote
• Neurological deficit• eg. hemiplegia, aphasia, ocular palsies
• Deafness • Blindness • Learning difficulty • Brain abscess• Hydrocephalus• Epilepsy
Follow up
Follow Up (long term FU is important)• Developmental assessment• Measurement head circumference• Ask about any occurrence of fits or any
beh. abnormalities (for epilepsy and behavioural problems)
• Assess vision, hearing and speech• Neurological assessment
Prevention
1. Antibiotic prophylaxis
• Meningococcal infection (all contacts)• Rifampicin 10 mg/kg OD for 2 days
• H. influenzae infection (only if <5yr child at home)
• Rifampicin 20 mg/kg OD for 4 days
• Alternative – Ciprofloxacin (for adult
contacts)
Prevention• 2. Vaccination
• HiB vaccine
• Meningococcal vaccine
• Pneumococcal vaccine
• 3. Adequate treatment of pyogenic
infection elsewhere in the body
Lumbar Puncture
Lumbar Puncture
• Informed consent from the parents are needed.• Parents should be told on why the test is needed• How the procedure are going to be carried out• The complications that can occur & its risk
To seek verbal consent for LP
• Introduce yourself• Check knowledge about condition of the
child and need for LP • Clearly explain about LP - why is it
necessary and what is involved (a technique to sample the fluid surrounding the brain and spinal cord, put a needle on the back and take few mls of fluid)
Why LP is necessary• Meningitis is potentially serious• The most serious forms of meningitis can be
effectively treated with antibiotics• Delay in making the diagnosis and starting
treatment worsens the outlook• LP is the only way of excluding meningitis• While it is possible to give an antibiotic without
performing a LP, there is less chance of making an accurate diagnosis
• Explain about analgesia, antiseptic• Explain what to expect afterwards – the fluid sample will be
sent to the laboratory for analysis to see any evidence of infection
• Explain risks – infection, leak, headache, technically unsuccessful
• Explain benefits – confirm diagnosis and management, selection of treatment, length of treatment, follow-up arrangements
• Invite patient any further questions, check understanding• Ask permission, using and open-ended, non-diirective
question
References
• Illustrated Paediatrics 4th edition• Nelson Textbook of Paediatrics 19th edition• Paediatric Protocols for Malaysia Hospitals
2nd edition 2010
• A 12 year-old boy was in his normal state of health until 5 days ago, when he developed a fever of 105.8 F (41C). Over the next 2 days, he developed stiff neck and began vomiting. He was brought to the emergency department (ED) when he developed altered mental status. In the ED, his heart rate is 135 bpm, blood pressure 120/70 mm Hg, respiratory rate 25 breaths/min, and temperature 104F (40C). He is combative, unaware of his surroundings,
• and does not follow instructions. Kernig and Brudzinski signs are present.
• ➤ What is the most likely diagnosis?• ➤ How would you confirm the diagnosis?• ➤ What treatment is indicated?• ➤ What are possible complications?
Investigation findings
• FBC –
WBC – 16,000/cmm
N 80%, L 15% • LP
CSF – turbid
cell – 1000/cmm, N 80%
Protein – 1 G/L
Sugar – 1.3 mmol/l
CASE STUDY
A one year 6 months old malay boy, came to A&E accompanied by his mother, with chief complaint of fits and fever.
Questions• State the immediate management• State the differential dx• Mention information you would like to
know.• Physical signs you would look for
Case study
• Fever – started in the morning, 39.5°C, not relieved by paracetamol
• Fits – started around 1.20pm, around 4 hrs after the onset of fever. Generalized tonic-clonic, uprolling of eyes, drooling of saliva and urinary incontinence. It lasted for 5 minutes.
• Postictal – crying, No drowsiness, no weakness of limbs and the baby did not sleep.
• Not drowsy, not irritable, no weaknesses, still feeding well during fever. No fast breathing, no cyanosis, no ear discharge, no rashes.
• No hx of head injury, no recent travelling to other country
• He had similar episode 2 mths ago. The fever was 38°C and fits 5 hrs after onset of fever. Similar generalized tonic-clonic with uprolling of eyes, drooling of saliva and incontinence. No post-ictal drowsiness or weakness and the fits lasted for 10 minutes. The baby was admitted in hospital for 1 day. No medication given.
Case study
• Antenatal history – GDM with insulin injection. C-sec, birthweight 4.03kg. After birth, baby was having respiratory distress and was given O2 via headbox, not intubated
• Developmental – normal • Family hx – youngest of 4, no similar
presentations in family or afebrile convulsion in family
• Physical examination?
Physical examination
• Anthropometry - normal• Neurologic examination – power and
sensory intact. No signs of cranial nerves palsy
• Anterior fontanelle not bulging• Neck stiffness absent• Eyeground (fundoscope): no abnormalities
detected• Liver and spleen not palpable
• Provisional diagnosis?• Recurrent Simple Febrile seizure
• Differential Diagnosis• Cerebral malaria• Meningitis• Encephalitis
• Investigation?
Investigation
• FBC – for presence of Infections• RBS• BUSE with creatinine, Ca, Mg• Infection screen
• Blood culture• Urine culture• Lumbar puncture (indication?)
Investigation
• Unnecessary in this case• EEG• Neuroimaging (MRI, CT)• Toxicology screening if suspicious of drug
exposure
Management