Meningitis Flashcards
What does the term meningism refer to
A headache, photophobia, vomiting and neck rigidity
State the 5 stages in the pathogenesis of meningitis
- Attachement to mucosal epithelial cells
- Transgression of the mucosal barrier
- Survival in the blood stream
- Entry into CSF
- Production of overt infection in the meninges with or without brain infection
State the bacteria that can cause meningitis
Neisseria Meningitidis
Strep Pneumoniae
E.Coli and Group B strep in neonates
State the viruses that can cause meningitis
Enteroviruses (echo, coxsackie A and B), Poliovirus, mumps, herpes simplex virus
State the percentage of patients with ventriculo-atrial shunts that develop ventriculitis and menngitis
10-30% usually caused by coagulase negative staph
Which conditions (infectious) can present with meningism
Influenza, tonsilitis, pneumonia, sinusitis, urinary tract infection and any severe bacteraemic illness
Which non infective causes can cause meningism
subarachnoid haemhorrage and migrain
Common presentation of meningitis
Upper respiratory tract infection with one of the meningsm features
State the neurological signs that can occur in meningitis
Cranial nerve palsies (VI, VII, or VIII)
Acute presentation
Less than 24 hours of signs and symptoms
Sub-acute presentaion
Signs and symptoms present for days usually viral
State illnesses associated with meningitis
Recent skull trauma, alcoholism and diabetes mellitus
Kernigs sign
With the hip flexed, the patients leg cannot be straightened due to hamstring spasm in meningsm
Other signs in meningitis
Neck stiffness
State the investigations conducted in meningitis
Blood cultures and lumbar puncture
State the microbiology tests conducted onto CSF
- Gram stain (and ZN if appropriate)
- Differential cell count (neutrophil polymorphs or lymphocytes)
- Antigen detection test (latex agglutination)
- Bacterial culture
- Mycobacterial or fungal culture (if appropriate)
- PCR for viruses (if appropriate)
- PCR for bacteria (if appropriate)
State the biochemical tests conducted in CSF
- Glucose (check serum level at same time)
* Protein
What specimens can be useful in viral meningitis
Nasopharyngeal secretions, EFTA blood and faeces
In DIC what will be seen on blood tests
low platelets (thrombocytopaenia), abnormal clotting and increased fibrin degradation products (FDP) will be seen.
Normal CSF
Gin clear and contains up to 5 WC/mm3
Bacterial meningitis CSF
Turbid, increased white cells (neutrophils), reduced glucose and increased protein
Viral meningitis CSF
Clear - turbid, moderate increase in cells (lymphocytes), normal glucose and moderate increase in protein
TB meningitis CSF
Clear to turbid, moderate increase in cells, reduced glucose and greatly increased proteins
State the principles of treating acute bacterial meningitis
- Early clinical recognition.
- Rapid detection of pathogen.
- Rapid initiation of appropriate bactericidal antimicrobial therapy.
- Early recognition and treatment of sequelae of septicaemia
(eg, DIC with shock, hypoxia, acidosis and adrenal insufficiency). - Antibiotic prophylaxis (when appropriate) of close contacts.
State the antibiotics often used in bacterial meningitis
Benzylpenicillin (4 hrly high dose), ceftriaxone.
Meningococcal Meningitis is a disease of
young adults and children
Describe the microbiology of meningococcal meningitis
Intracellular gram negative diplococci may be seen on gram stain of CSF and antigen tests may be positive for meningococci.
State the clinical symptoms of meningococcal meningitis
Meningitis with our without accompanying septicaemia, is the commonest mode of presentation. The patient experiences an acute onset of symptoms of meningism, systemic upset and a petechial skin rash
How is fulminant meningococcal septicaemia characterised
suddenness of symptoms causing rapid deterioration and loss of conciousness, fever, septicaemic shock with renal failure and disseminate intravascular coagulation
State the earlier signs of meningitis
Leg pains, cold hands and feet and abnormal skin colour
Chronic meningococcaemia
Uncommon illness that may last weeks or even months with a rash, joint pains, malaise and fever sometimes complicated by endocarditis.
Antibiotic given to patient with meningococcal meningitis prior to transfer to hospital
Parenteral penicillin (3-4MU).
State the treatment of meningococcal meningitis
Ceftriaxone and then rifampicin or ciprofloxacin on discharge
Most frequent cause of bacterial meningitis in adults
Pneumococcal meningitis
State the predisposing factors of pneumococcal meningitis
Pneumonia, sinusitis, endocarditis, head trauma, alcoholism or splenectomy
State the appearance o f pneumococci on gram stain
Gram positive diplococci with are alpha haemolytic on blood agar
State the important virulence factor of strep pneumococci
Antiphagocytic capsule
State the treatment of choice for pneumoccal meningitis
Benzyl penicillin
State the initial treatment given to pneumococcal meningitis
Ceftriaxone
State the mortality rate of pneumococcal meningitis
30-50%
State the complications of pneumococcal meningitis
Loss of hearing, cranial nerve palsies, hemiparesis, hydrocephalus and seizures
What medication can be given to reduce chances of pneumococcal complications
Dexamethasone
State the vaccination of pneumococcal meningitis and who it is given to
Pneumovax, given to all those over 65 and high risk groups
List the high risk groups who should be given the pneumovax vaccine
Splenectomy, diabetes, cardio-resp disease, renal disease and HIV
Who does Hib meningitis tend to effect
Young children
State the usual picture of Hib meningitis
Mild upper respiratory tract infection followed by rapid deterioration and there are often no signs of meningitis, with fever and drowsiness being more common
How does H.influenzae appear on gram stain
Mixture of gram - and gram + cocci and bacilli
State the most common form of capsule which occurs in type B h.influenza
type B
State the main treatment of H.influenzae meningitis
Cefotaxime
State the prophylactic medication given to contact of those with Hib meningitis
Rifampicin
State the vaccine available for Hib meningitis
Hib recommended for all infants from two months of age, three doses should be given with an interval of one month between doses
State an important cause of neonatal meningitis
Gram + Listeria monocytogenes
State the treatment of listeria meningitis in adults over 55
IV ampicillin
What does meningitis follow in TB
Rupture of a sub-ependymal tubercle into the subarachnoid space
State the presentation of TB meningitis
Lethargy, chronic headache and a change in mentation
When should TB meningitis be considered
CSF glucose is reduced and Gram stain and conventional culture are negative, especially in the absence of any previous antibiotic therapy
What other investigations can be helpful in TB meningitis
CXR or CT head (showing tuberculoma)
What type of HSV can cause meningitis
Type 2
State the clinical features of viral meningitis
non-specific prodromal illness, followed by rapid onset of headache, photophobia, low grade fever and a stiff neck. Patients are usually lucid and alert
What might be present with enteroviral meningitis
Petechial Rash
State the investigation of choice for viral meningitis
PCR of CSF
How long does recovery take in Enteroviruses and parechoviruses
72 hours
State the treatment of herpes simplex meningitis
Aciclovir IV
State the most important cause of fungal meningitis especially in HIV infection
Cryptococcal meningitis
State the investigations conducted into fungal meningitis
Gram stain of CSF or India Ink of CSF which shows capsule , CSF and serum cryptococcal polysaccharide antigen
State the clinical features of fungal meningitis
Low grade fever, headache, nausea, lethargy, confusion and abdominal pain
State the treatment of choice of fungal meningitis
Parenteral amphotericin sometimes in combo with flucytosine or high dose fluconazole
How does neonatal meningitis differ from adult meningitis
The symptoms and signs are not specific and the bacteria commonly incolved are group B strep, E.coli and Listeria
State the predisposing factors to neonatal meningitis
Low birth weight, prolonged rupture of membranes and maternal diabetes mellitus
State the incidence of neonatal meningitis
1/2,500
What does listeria cause in pregnant women
a febrile, flu-like, bacteraemic illness which can only be diagnosed by blood cultures. The infection may cause abortion or lead to neonatal sepsis, including meningitis
Early onset neonatal meningitis
within 3 days of birth and associated with prematurity or a difficult or prolonged birth. Marked respiratory distress, bacteraemia and a high mortality (50%) are typical. The organism has usually been acquired at birth from the mother’s genital tract.
Late onset neonatal meningitis
more than one week
after birth. The infection is typified
by bacteraemia and meningitis but pulmonary involvement is rare. Mortality is 10-20%. The organism may have been spread by cross-infection from other mothers, babies or healthcare workers.
Treatment of neonatal meningitis
Parenteral ampicillin (to cover group B streptococci and Listeria) and gentamicin or cefotaxime (to cover the gram negative bacilli) are used in combination, until the causative organism is identified.
State the mortality of neonatal meningitis
50%
