Infection - meningitis Flashcards
What is meningitis?
Inflammation of the meninges
Usually due to infection
What is the pathogenesis of meningitis?
Attachment to mucosal epithelial cells Transgression of mucosal barrier Survival in blood stream Entry into CSF Production of overt infection in meninges (with or without brain infection - encephalitis)
What are the common bacterial causes of meningitis>
Neiseria meningitidis (mengiococcus)
Strepococcus pneumonia
Neonates - E. Coli + Group B streptococci
What are the common viral causes of meningitis>
Enteroviruses -Echoviruses -Parechoviruses -coxsackie viruses -polio(not in UK) Mumps (rarely) Herpes simplex
What are the less common causes of meningitis ?
Haem influ B Listeria monocyotgenes Mycobacterium TB Leptosporosis Borelia burgdorferi Crytococcus neoformans HIV Varicella virus Epstein-barr virus
What are the non-infective causes of meningitis?
Tumours
Causes aseptic meningitis
What is aseptic meningitis?
High protein + lymphocytes
No organism detected
How does meningitis present?
Heaache Photophobia Neck stiffness Vomiting Lethargy Clouding conciousness
When should you expect bacterial meningitis?
Clouded conciousness
How long are symptoms present in acute presentation of meningitis?
Less than 24 but rapidly progressive
What causes sub acute presentation of meningitis? What is the time period?
1-7 days
All viral and 65% bacterial. Fungal also possible
What are the side effects for late treatment of bacterial meningitis?
Long term deafness
Fits
Mental impairment
What are the key points in a general exmaination in suspected meningitis?
Pyrexial?
Level of conciousness?
Rashes - skin + conjunctival petechia in 60% with mengiococcal
What are the key points in a cardiovascular exmaination in suspected meningitis?
Pulse - brady/tachy? Blood pressure (septic shock?)
What are the key points in a neurological exmaination in suspected meningitis?
Focal neurological signs (TB/cryoticiccal meninigits)
Papilloedema (unusual - consider space occupying lesion)
What are the traditional physical signs in meningitis?
Kernig sign (hip flexed, patients leg cannont be straightened due to hamstring spasm) Flex neck in attempt to touch chin - difficult with neck stiffness
What specimines should you collect in suspected meningism?
Blood cultures (before antibiotics if possible, but take anyway even if antibiotics taken). Then treat with best guess
Lumber puncture
CT if papillodema to rule out lesion
What are the CSF findings in bacterial mengitis?
Looks turbid (nroamlly clear)
Cells - greatly increased (normally small unmbers)
Predominant cell type - neutrophils (normally phymphocytes)
Glucose reduced (normally 60% of blood level)
Protein greatly increased
What are the CSF findings in viral mengitis?
Looks clear- turbid (normally clear)
Cells - moderate increased (normally small unmbers)
Predominant cell type - lymphocytes (normally lymphocytes)
Glucose normal
Protein moderate increased
What are the CSF findings in TB mengitis?
Looks turbid (nroamlly clear)
Cells - moderate increased (normally small unmbers)
Predominant cell type - lymphocyte or mixed (normally phymphocytes)
Glucose reduced (normally 60% of blood level)
Protein greatly increased
How do you treat acute bacterial meningitis?
Use antibiotic that penetrates the CSF
Benzylpenicillin - if CSF inflamed + 4hrly doses
Ceftrizone in bacterial menigitis
What is the epidemiology of menigococcal meningitis?
Primarily young children
Sporadic disease
University student outbreaks in recent years
What is fulminant mengiococcal speticaemia?
Startling suddens of symptoms causing rapid deterionation in consciousness, fever, septicaemic shock with renal failure _ disseminated intravascular coagulation
Not techincally meningitis as CSF sterile
Purplish rash charecteristic
What is the management for fulminant mengiococcal septicamia?
Antiobiotics by GP immediately - penicillin
Modified after blood tests
What is the rash assciated with mengioccoal disease?
Purplish rash that does not blanche under pressure
However, earlier signs exist (cold extremities, leg pains)
What factors indicated a bad prognosis of meningitis?
Delay of antibiotics
Extremes of age
Purpuric leasions
Shock with absence of signs of meningitis
Lab:
Metabolic acidosis
Abscence of polymorph leucotosis
Who should meningitis be reported to?
Local consultant in health protection
What is the epidemoiology of pneumococcal meningitis?
Most frequent cause of bacterial meningitis Predisposing factors: Pneumonia Sinusitis Endocarditis Head trauma Alcoholism Splenocetpmy
What is the microbiology of penumoccoci?
Gram positive
a haemolytic on agar jelly
What are the clinical features of pneumococcal meningitis?
Often acute within 1-2 days
Focal neurological signs or altered conciousness more common in haemphilus or mengiococcal
Concurrent infection in sinuses
What is the treatment for pneumoccoal meningitis?
Early administration of high dose ceftrixone
What are the complications of pneumococcal menginitis?
Death Loss of hearing Cranial nerve deficits Hydrocephalus Seizures
Who are immunised against pneumococcal meningitis?
Patients with Splenectomy Diabetes mellitus Chronic renal disease Cardio-respiratory disease HIV
What is the epidemiology of haemophilus inflenzae B meningitis?
Young children affected
Mild URTI followed by rapid deterioation
What is the treatment of choice in haemophilus influenzae meningitis?
Dexamethasone
What is the clinical picture in TB meningitis?
Meningitis follows rupture of subependymal tubercle
Low grade fever + extrameningeal TB
Lethargy
Chronic headache
Change in mentation
How do you investigate suspected TB meningitis?
Culture most sensitive
Repeated LP
CT head
What is the epidemiology of viral meningitis?
Young adults or children
Enteroviruses most common
Late summer/early autumn
What are the clinical features of viral meningitis?
No specific prodrome Rapid onset headache Photophobia Low grade fever Stiff neck
Patients normally altert and lucid
Rash may be present
What are the investigations into suspected viral meningitis?
PCR of CSF
Shows lymphocytosis with normal glucose
How do you treat viral meningitis?
Enteroviruses
Normally none needed as recover within 72 hours
If immunocomprimised/chronic infection - IV immunoglobulin may be used
For herpes - aciclovier IV, then oral
What yeast is most likely to cause meningitis?
Crytococcus neoformans
Occurs in HIV
Sometimes in diabetes + immunosupression
What is the clinical presentation of fungal meningitis?
Most commonly subacute onset of symptoms Low grade fever Headache Nausea Lethargy Confusion Abdominal pain
How do you treat fungal meningitis?
Amphotericin IV
Sometimes with fluconazole
How does neonate meningitis differ from adult meningitis?
Symptoms usually non specific or not well localised
Bacteria involved often E coli, L monocytogenes, group B streptococci
Enteroviruses
Parechoviruses
What are the clinical signs of early onset neonatal meningitis?
Early onset - within 3 days of birth
Marked respiratory disrtress
Bacteraemia
High mortality
Associated with premature or difficult/prolonged birth
What are the clinical signs of late onset meningitis?
More than one week after birth
Bacteraemia + meningitis
Pulmonary involvment rare
Moraltity 10-20%
How do you diagnose neonatal meningitis?
Bacterial - neonate CSF + blood cultures
Viral - neonate CSF, EDTA blood, faeces + nasopharyngeal secretions
What is the prognosis of neonate meningitis?
High mortality - up to 50%
Neurological + development difficulties in around 33%
How do you prevent neonatal meningitis?
High risk mothers given chemoprophylaxis during labour
What are the clinical features for Hep A?
Usually mild + subclinical Often children under 5 Fever Malaise Anorexia Nausea Vomiting Upper abdominal pain Jaundice Self limiting
How is hep A spread?
Faecal oral route
MSM
IV drug users
What is the treatment ofr hep A?
Supportive - no specific treatment as usually self limiting
What are the clinical features of hep B?
Anorexia Lethargy Nausea Fever Abdominal discomfort Arthralgia Urticarial skin lesion Dark coloured urine Jaundice
What antigens are seen in Hep B?
HBsAg (surface antigen)
HBcAg (hep B core antigen
HBeAg (chronically infected)
What are the routes of transmission for Hep B?
Vertical (mother to child), sexual, bloods etc
What are the predisposing factors to Hep B?
Injecting drug users Multiple secual partners Immigration from areas of high endemncity Learn disability in care Haemodialysis Tattoo
How do you diagnose an acute HBV infection?
HBsAg in serum on presentation
However, in late disease may have disappeared
(In which case diagnose with anti-HBc IgM antibodies)
What are teh clinical features of chronic HBV infection?
Persistence of HBsAg for more than 6 months 5-10% become chronically infected Risk to develop: Chronic liver disease Membranous glomerulonephritis
Jaundice unusual until late disease
What is the prognosis of hep B?
25% to go on to cirrhosis
Hepatoma can cause cancer
When do you treat hep B?
Asymptomatic with raised ALT consider antiviral therapy
So should anyone with liver damage or cirrhosis
Otherwise: 2+ of
HBV DNA >2000 IU/ml
Raised ALT
Significant liver inflammation
How do you treat hep B?
Long acting a intergeron via subcut injection
Entecavir
Tenofovir
In specialist clinics!
How are reccomended to get the HBV vaccine?
Healthcare personnel Travellers in endemic areas Renal dialysis patients People who change sexual partners frequently Some Police/emergency worers
How is passive immunisation for hepatitis given?
Through administration of hepatitis B specific immunoglobulin
What are the clinical features of Hep C?
Usually subclinical
Malaise
Anorezia
Fatigue
Jaundice + sever hepatitis can occur
Symptoms rare in chronic HCV
Hoever, AST/ALT levels fluxuate in chronic disease
What is the main mode of transmission for Hep C?
IV drug users
Transfusions
Needle-stick injuries
Sexual transmission
How do you diagnose HCV?
IgG (although false positive)
HCV-RNA
How do you manage Hep C?
Alcohol abstention help
Pegylated a-interferon + rivavirin
How does one accquire Hep D?
Either co-infection (at the same time) as getting hep B
Or at a later date (superinfection)
How do you diagnose Hep D?
IgG and IgM to serum HDV, HDV-RNA and HDAg
How do you manage hep D?
Pegylated a-interferon
What are the clinical features of Hep E?
Subclinical or mild ilness in women + young people
Severe in elderly men
Liver failure may develop
Persitant infection can be present in immunocompromised patients
What is the epidemiology of hep C?
Enterically transmitted
Most common acute form of hepatitis in UK
Transmitted from pigs
How do you diagnose Hep E?
IgG and IgM and HEV-RNA
What is the treatment for Hep E?
Self limiting - no treatment
In immunocormprimised - ribavirin to achieve viral clearance
What other infections can cause hepatitis (non viral)?
Leptospirosis
Q fever
Psittacosis/ornithosis
What is Q fever?
Zoonosis
coxiella burnetii
Acquired occupationally
What are the clinical features of Q fever?
Self-limiting hepatitis with Jaundice
Pneumonia
Meningoencephalitis
Acute rarely fatal
How do you diagnose Q fever?
Serological
What is psittacosis?
Zoonosis - chlamydophila dound in bird faeces/bodily fluids of infected animals
Human to human rare
What is the presentation of psittacosis?
Subclinical Febrile like flu illness Pnemonia Typhoid like illness Hepatitis (jaundice sometimes), cardiac (endocarditis/myocarditis) Neurological (meningitis, encephalitis) Can be fatal
When are health care workers excluded from doing an exposure prone procedure?
Hep B e antigen positive
Hep B surface antigen positive with high levels of DNA
Hep C PCR positive
What is the process after exposure to blood/bodily fluids?
Encourage bleeding
Washing injury thoroughly
Cover with waterproof plaster
Report immediately
