25 Central nervous system infections Flashcards

Question

What are different clinical features/ groups seen in these causes of bacterial meningitis? Neisseria meningitidis Haemophilus influenzae Streptococcus pneumoniae

Answer 1

Neisseria meningitidis - children/ adolescents. Skin rash. Acute onset <24 hours Haemophilus influenzae - children <5. Onset 1-2 days Streptococcus pneumoniae - children <2 and elderly. Onset follows pneumonia/ sepsis

Answer 2

Neisseria meningitidis - 10% mortality, sequelae <1% Haemophilus influenzae - 5% mortality, sequelae 10% Streptococcus pneumoniae - 25% mortality, sequelae 20%

Answer 3

``` Sore throat Headache Drowsiness Fever Neck stiffness Photophobia Rash - petechiae ``` Septicaemia causes DIC, endotoxaemia, shock and renal failure. In severe cases, bleeding into brain/ adrenal glands can cause addisonian crisis termed Waterhouse-Friedrichsen syndrome

Answer 4

Bloods - CRP/ WCC/ coag/ platelets CT/ MRI LP Serology not helpful as disease too acute for antibody response to occur

Answer 5

Capsulated type b can occasionally invade blood/ meninges Uncapsulated other strains are common, and present in throat of most healthy people Maternal antibodies protect infant until 4 months of age, but this weakens, and there is a window of susceptibility before child produces own antibodies.

Answer 6

``` <2 years old Elderly Sickle cell Splenectomy patients Head trauma ``` Immunity is type specific, and there are over 85 capsular types of strep pneumoniae Vaccine recommenced in childhood, and those high risk - sickle cell, splenectomy, HIV, immunodeficiency.

Answer 7

Children Elderly Immunocompromised Use ceftriaxone and amoxicillin because listeria is less susceptible to penicillin, so combination therapy better

Answer 8

Immature innate and adaptive immune systems Difficult diagnosis - may only have lethargy, poor feeding Often leads to permanent neurological sequelae such as cerebral palsy, cranial nerve palsy, epilepsy, mental retardation, hydrocephalus

Answer 9

Benzylpenicillin and gentamicin Antibiotics given in pregnancy to eliminate carriage, but does not guarantee this

Answer 10

Insidious onset over weeks If high TB prevalence - presents in children aged 0-4 If low TB prevalence - presents in adults

Answer 11

Primary lesion in lung Bacilli move to lymph nodes Lymphatics drain into lymphatic duct/ SVC Moves in bloodstream to CNS causing tubercles Tubercle ruptures into subarachnoid space Bacilli spread in CSF

Answer 12

Cryptococcus neoformans - immunocompromised Coccidioides immitis

Answer 13

Slow, over days or weeks

Answer 14

Cryptococcal antigen in blood/ CSF India ink stain CSF Amphotericin B + flucytosine

Answer 15

North/ South america Rarely visible in CSF, cultures positive <50% cases Detect antibodies in serum Amphotericin B or fluconazole

Answer 16

Amobes: - Naegleria fowleri - Acanthomoeba - Balamuthia madrillaris Can infect healthy individuals - plasmodium - toxoplasmosis

Answer 17

Fresh warm water - lakes, swimming pools Feeds on bacteria North/ South America, Asia Via olfactory tract and cribiform plate. Rapid onset

Answer 18

Amphotericin B, with miconazole and rifampicin. Miltefosine addition has shown some benefit Mortality approximately 95%

Answer 19

CSF microscopy Brain biopsy PCR/ serology in specialist centres

Answer 20

Enetroviruses - echoviruses, coxsackie A/B, poliviru HSV VSV CMV Paramyxovirus - mumps, nipah (pig farms Malaysia) Rabies Flavivirus - JE, WNV HIV Influenza H5N1 has been shown to cause encephalitis

Answer 21

AI encephalitis, commonly: VGKA receptor NMDA receptor

Answer 22

HSV1 - older patients. Reactivation in trigeminal ganglion, infection then passing to primary lobe of brain. Can also occur as primary infection HSV2 - neonate. Acquire from mother due to shedding in genital tract

Answer 23

Herpetic skin/ mucosal lesions CT/ MRI - temporal lobe enhancement CSF HSV DNA PCR EEG

Answer 24

70% mortality if untreated 21 day course aciclovir

Answer 25

VZV - reactivation or new infection. Encephalitis can occur later CMV - primary infection in utero, or reactivation when immunosuppressed e.g bone marrow transplant

Answer 26

Hand foot and mouth disease Outbreaks have been associated with encephalitis in children <5, leaving permanent neurological damage

Answer 27

Fruit bat natural reservoir - virus in urine/ saliva Pigs eat infected food Aerosol transmission (unclear) to humans via close contact Initially thought to be JE. Resulting in culling of 1 million infected pigs in region

Answer 28

Single stranded RNA virus | Bullet shaped

Answer 29

1 - worldwide classic rabies virus 2, 3, 4 - African bat virus 5, 6 - European bat Lyssasviruses (EBLV)

Answer 30

Viruses excreted in saliva of infected dogs, foxes, jackals, wolves, skunks, raccoons, bats or transmission from humans Virus can be in host saliva before symptoms present. If asymptomatic by day 15, then unlikely to have rabies. Dogs are source of 99% of human infection. Islands such as UK, Australia, Japan are free of rabies because of strict control on import of animals

Answer 31

Typically 4-13 weeks, can be 6 months Virus travels up motor or sensory neurones Eventually reaches limbic system - causing behavioural change Incubation period depends on where bite occurs e.g distal bite will take longer to spread No antibody response as antigen remains within infected cells.

Answer 32

``` Pain at bite site Sore throat Headache Fever Difficulty swallowing water due to muscle spasms jaw (hydrophobia) Convulsions Paralysis ``` Once rabies has developed it is invariably fatal, leading to cardiac/ respiratory arrest

Answer 33

Viral antigen by immunofluouresence Viral RNA PCR skin biopsy Brain biopsy Intracytoplasmic inclusions called Negri bodies are seen in neurones

Answer 34

Prompt cleaning of wound Cinical observation of animal - does it have rabies Rabies immunoglobulin (RIG) provides passive immunisation. Administered IM around wound site Active immunisation with killed rabies virus

Answer 35

JE WNV SLE Dengue/ YF are other examples of flaviviruses

Answer 36

China/ India 70000 cases/year Children - mortality 30% Adults usually already been infected

Answer 37

Pigs and wading birds - intermediate hosts Culex mosquito

Answer 38

Culex mosquito transmits to birds Feeding mosquitoes obtain from infected birds, which then bite humans who are incidental hosts Birds can have viraemia without death, or can have sudden mass death Common in USA now. Reported in multiple Eastern European countries

Answer 39

Viral RNA PCR IgM - serum/ CSF Treatment - supportive No vaccine Mosquito control programmes

Answer 40

HIV itself can move into CNS, and cause mild mengitic illness CMV JC virus - PML Cryptococcus Toxoplasma

Answer 41

Anterior horn cells affected causes pure motor symptoms, and results in acute flaccid paralysis. Examples include: - polio - coxsackie - enterovirus 1 - WNV Non-specific myelitis - CMV - EBV - HSV - VZV - HTLV-1 - presents as tropical spastic paraparesis - HIV

Answer 42

Inflammatory demyelinating condition of peripheral nervous system. Can rapidly lead to ascending muscle weakness. Usually little sensory loss. May require mechanical ventilation

Answer 43

2-4 weeks preceeding URTI, diarrhoeal disease, or other infection, prior to symptoms developing

Answer 44

Associated with variety of infections, including vaccination with non-infectious material e.g influenza vaccine ``` EBV CMV HIV WNV Zika ``` Campylobacter Jejuni - 1/3 of cases Mycoplasma pneumoniae Borrelia burgdorferi

Answer 45

Supportive - - ventilation - IV immunoglobulin - plasma exchange

Answer 46

``` African Trypanosomiasis Cysticercosis Hydatid Plasmodium Toxoplasma Toxocara ```

Answer 47

Aseuxal stages of plasmodium (in humans) adhere to capillary walls, which affects BBB

Answer 48

Toxocara cati - cat Toxocara canis - dog Usually infect children when eggs from cat/ dog faeces are infested. Eggs hatch in GI tract. Larvae migrate to various tissues including brain. Humans dead end hosts. Granulomas form around larvae, which can cause encephalitis

Answer 49

Steroids | Albendazole

Answer 50

``` Actinomyces Brucella Lyme disease Nocardia Syphilis TB ```

Answer 51

Cysticercosis | Toxoplasma

Answer 52

``` Blastomycosis Candidiasis Cociddiomycosis Cryptococcus Histoplasmosis ```

Answer 53

Spores enter a wound, and if necrotic tissue present, toxin tetanospasmin produced. Carried up peripheral nerves, where it binds to neurones and blocks release of inhibitory mediators in spinal synapses, causing overactivity of motor neurones. Can also move along sympathetic nerve axons, leading to overactivity of sympathetic nervous system Infection of umbilical stump can cause neonatal tetanus

Answer 54

3-21 days Often clinical diagnosis, and organisms often not isolated from wound. Only small number of organisms required to produce toxin

Answer 55

``` Hyperreflexia Muscle rigidity Muscle spasms Trismus Dysphagia Neck stiffness ``` Tachycardia Sweating

Answer 56

Clean wound Penicillin Tetanus toxoid vaccine booster - lasts for 10 years If severe - Anti-tetanus immunoglobulin

Answer 57

Absorbed from cut, into blood Then acts on peripheral nerve synapses by blocking release of acetylcholine. It is type of food poisoning affecting motor and autonomic nervous systems In infants, they can ingest by pacifiers covered in honey. Causing infant botulism

Answer 58

2hr-72hr Descending weakness and paralysis including dysphagia, diplopia, vomiting, vertigo, respiratory muscle failure. No GI symptoms or fever Infants develop generalised weakness - floppy baby, but usually recover

Answer 59

Usually clinical diagnosis | Toxin can be found in suspected food

Answer 60

Trivalent antitoxin - Type A/ B/ E toxin given promptly Respiratory support

Answer 61

Kernig's sign - flex hip 90deg, try and straighten leg Brudzinski's sign - bend knees onto bed, flex neck. Will make neck pain worse Each sign only has 5% rule out percentage

Answer 62

GBS E. Coli Listeria Outbreaks form gram neg rods such as Serratia, Citrobacter, Klebsiella in NICU

Answer 63

Strep pneumoniae N meningitidis Hib - if not immunised M TB

Answer 64

Strep pneumoniae Listeria Listeria

Answer 65

Complement deficiency increases risk infected encapsulated organisms: Strep pneumoniae N meningitidis Hib Listeria Cryptococcus (not bacteria)

Answer 66

``` S aureus Coagulase negative staph Corynebacteria Propionibacterium Pseudomonas ```

Answer 67

S aureus Pseudomonas Gram negative rods

Answer 68

S pneumoniae Other oral flora Hib Pseudomonas

Answer 69

papilloedema or other signs of raised intracranial pressure suspicion of intracranial or cord mass congenital neurological lesions in lumbrosacral region signs suggesting raised intracranial pressure reduced or fluctuating level of consciousness (Glasgow Coma Scale score less than 9 or a drop of 3 or more) relative bradycardia and hypertension focal neurological signs abnormal posture or posturing unequal, dilated or poorly responsive pupils papilloedema abnormal 'doll's eye' movements " shock extensive or spreading purpura after convulsions until stabilised coagulation abnormalities platelet count below 100 x 10^9/litre receiving anticoagulant therapy local superficial infection at the lumbar puncture site

Answer 70

Adult - ceftriaxone Pregnant - ceftriaxone + amoxicillin Post neurosurgery - meropenem + vancomycin. Add intrathecal antibiotic if EVD in situ Post open trauma - ceftriaxone + metronidazole + gentamicin

Answer 71

Cochrane review showed reduced mortality in S pneumoniae only. Stop steroids if other organism is cause Showed reduced deafness and neurologic deficit in all causes Give 5 days dexamethasone 10mg QDS

Answer 72

N meningitidis - 5 days S pneumoniae - 14 days Listeria - 21 days GBS - 21 days E. coli - 21-28 days S. aureus - 28 days Haemophilus - 10 days Can consider OPAT if had 5 days therapy, and clinically improved - Ceftriaxone 2g BD is example

Answer 73

anti-NMDA receptor Ab voltage-gated potassium channel Ab

Answer 74

Acute disseminated encephalomyelitis Immune mediated inflammatory demyelinating condition, predominately affecting white matter of brain/ spinal cord. Not necessarily directly due to infection, but is related to recent viral illness e.g measles, rubella, chickenpox, or following recent vaccination

Answer 75

Enterovirus - multiplies in GI tract send CSF for viral PCR

Answer 76

Benzylpenicillin 1.2g IM Ceftriaxone 2g IM Cefotaxime 2g IM If allergy penicillin/ cephalosporins - hold off antibiotics until arrival hospital.

Answer 77

If on prophlyactic LMWH - do not perform until 12 hour after If not on prophylactic LMWH - do not commence until 4h post-LP If on treatment dose LMWH - do not perform until 24 hour after If on UFH - can re-start 1 hour after LP Aspirin - can proceed with LP clopidogrel should be avoided 7 days before LP. But if benefits outweigh risks, can give platelet cover, and perform 8 hours after dose DOAC - discuss with haematology. Dabigatran has reversal agent

Answer 78

Platelets >50 - unless rapidly falling INR below 1.5

Answer 79

Blood cultures Pneumococcal/ meningococcal PCR Throat/ rectal swab for enterovirus Throat swab - neisseria Procalcitonin - can help point towards bacterial rather than viral cause HIV test ``` LP - opening pressure protein glucose - if above 2.6, unlikely to be bacterial cell count microscopy 16s PCR if bacterial considered Viral PCR ``` Viral PCR - HSV/ VZV/ Adenovirus/ Enterovirus/ Parechovirus CSF results can be normal if immunocompromised If first episode of meningitis, then does not need investigation for immunodeficiency at this point. If second episode - check immunology

Answer 80

Isolate patient with respiratory isolation until had 24 hours of antibiotics Antibiotic chemoprophylaxis should be given to healthcare workers who have been in close contact with a patient with confirmed meningococcal disease ONLY when exposed to their respiratory secretions or droplets for example during intubation or as part of CPR when a mask was not worn

Answer 81

Epilepsy Hearing difficulties - hearing test Psychiatric issues Limb amputations Headache Neuropathic pain

Answer 82

Normally self-limiting illness - does not require anti-virals Some people treat, but no evidence of benefit. Recurrent HSV2 meningitis is sometimes called Mollaret's meningitis, and some decide to put on prophylactic anti-virals.

Answer 83

Aciclovir 10mg/kg TDS Reduce dose if renal impairment Treat 14 days - perform repeat LP, and can stop treatment on day 14 if CSF negative by PCR. If positive by PCR, continue for further 7 days 21 days treatment if immunocompromised Viral PCR negative on initial LP - - An alternative diagnosis has been made - HSV PCR in the CSF is negative on two occasions 24-48 hours apart, and MRI is not characteristic for HSV Encephalitis - HSV PCR in the CSF is negative once >72 hours after neurological symptom onset, with unaltered consciousness, normal MRI (performed >72 hours after symptom onset), and a CSF white cell count of less than 5/mm3 No evidence for corticosteroids

Answer 84

VZV encephalitis - no specific treatment ``` Enterovirus encephalitis - no specific treatment is recommended for enterovirus encephalitis. If severe disease pleconaril (if available) or intravenous immunoglobulin may be worth considering ```

Answer 85

Vaccination for MenB/ ACWY/ Hib/ PCV13 Offer vaccination to close contacts

Answer 86

Tick bite Unpasteurised milk from goats/ sheep/ cows

Answer 87

No treatment available Vaccination can provide protection. Offer to those going to Europe doing outdoor leisure pursuits such as forestry working, camping, rambling and mountain biking, during tick season (spring to early autumn)

25 Central nervous system infections Flashcards

(112 cards)