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