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Faculty LO - 25i Meningitis

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Faculty LO - 25i Meningitis Powered By Docstoc
					        Week 27 LO’s

27.1 To be able to develop a differential diagnosis for the febrile child
       BCS

Differential Diganosis                                      - factitious (rarely)
       - an incorrectly taken                               - true fevers are usually due to :
            temperature or unreliable                viral infections (esp. enteroviruses)
            thermometer must be                      missed bacterial infections (e.g.
            excluded                                    appendix rupture, osteomyelitis)
       - environmental causes (over-                 leukemia
            dressing, recent hot baths,              lymphoma
            etc.,.) must be excluded                 juvenile rheumatoid arthritis
       - dehydration                                 enteric fever
       - drugs                                      Kawasaki's disease (a multisystem disease
       - diurnal variation                          - cutaneous lymph node syndrome)
       - undue parental anxiety

27.2 To be able to recognize the clinical syndrome of bacterial meningitis
       BCS

Meningitis is any inflammation of the leptomeninges and the underlying subarachnoid CSF.
It can be clinically divided into three subgroups:
- Subacute (either infectious or non-infectious, often viral)
- Chronic (as above)
- Acute (almost always bacterial)

In acute meningitis the patient presents with severe systemic symptoms within less than a day
of onset. However, 75% of bacterial meningitis cases present a subacute picture, so it is a fair
rule of thumb to say that acute meningitis means bacterial meningitis but bacterial meningitis
does NOT mean acute meningitis on presentation.

History:
a) Onset – helps decide whether the infection is bacterial or not; 25% with bacterial
    meningitis present acutely within 24 hours of onset; the majority of patients with
    viral meningitis present with subacute neurological symptoms developing over 1-
    7 days; chronic meningitis symptoms of over 1 week suggests viruses, TB,
    syphilis, fungal (cryptococcus) and carcinomatous meningitis
b) Travel history
c) Immunization (particularly for infants and old people – pneumococcal vaccination)
d) Risk Factors:
    - Age: 60 years or older, 5 years or less
    - Immunosuppression (caveat: Immunosuppressed may not show dramatic
        signs of fever or meningitis)
    - Crowding (e.g., military recruits) increases risk for outbreaks of
        meningococcal meningitis
    - Splenectomy and sickle cell disease increase risk of meningococcal
        meningitis secondary to encapsulated organisms
    - Social: Alcoholism and cirrhosis; multiple etiologies of fever and seizures in
        these patients makes meningitis challenging to diagnose; IV drug use
    - Chronic medical conditions: IDDM, thalassemia major, bacterial endocarditis,
        malignancy, congenital cranial anomalies, CF, renal disease, adrenal
        insufficiency.
    - Recent exposure to others with meningitis, with or without prophylaxis
    - Contiguous infection (e.g., sinusitis, otitis media, prodromal infections)
   -   Dural defect (e.g., traumatic, surgical, congenital)
   -   Ventriculoperitoneal shunt
   -   In neonates:
       - delivery <37 weeks gestation
       - ruptured membranes = or > 18 hours previously delivered child with
           Group B Strep infection
       - UTI or bacteriuria with Group B Streptococci during pregnancy

Symptoms
   Classic (often not evident in infants or often in the elderly):
          Headache
          Nuchal rigidity (generally not present in children less than one year-old or
             patients with altered mental status)
          Fever and chills
          Photophobia
   Other Common Symptoms:
          Vomiting
          Prodromal URTI symptoms (viral and/or bacterial, the sniffles....)
          Seizures (30-40% in children, 20-30% in adults)
          Focal neurological symptoms (including focal seizures)
          Altered sensorium; confusion may be sole presenting complaint, especially in
             the elderly
   Symptoms in Infants:
          Fever
          Lethargy and/or change in level of alertness*
          Poor feeding and/or vomiting
          Respiratory distress, apnea, dyspnoea, cyanosis
   Partially treated meningitis (up to 40% of patients with meningitis were previously
     treated with oral antibiotics): seizures may be the sole presenting symptom; fever and
     changes in level of alertness or mental status occur less commonly than in untreated
     meningitis
   Low-grade ventriculitis associated with ventriculoperitoneal (VP) shunt: less
     dramatic presentation, with headache, nausea, minimal fever and malaise.
   Fungal Meningitis:
     Headache, low-grade fever and lethargy, especially if immunocompromised. May be
     mild with fluctuating symptoms.
   Tuberculous Meningitis: Fever, weight loss, night sweats and malaise, with or
     without headache and meningismus. May follow a protracted course with a vague
     non-specific presentation.

Physical examination findings:
- Often an URTI, pulmonary or otitis media co-infection.
    Signs of Meningeal Irritation:
    Nuchal rigidity or discomfort on neck flexion (don’t expect it in babies though)
    Kernig's Sign (i.e., passive knee extension in supine patient elicits neck pain and
       hamstring resistance) - many doctors now say this is a waste of time
    Brudzinski’s Sign (i.e., passive neck or single hip flexion is accompanied by
       involuntary flexion of both hips)
    Papilledema is present in only one-third of meningitis patients with increased
       intracranial pressure; it takes several hours to develop.
    Focal neurologic signs:
       Isolated cranial nerve abnormalities (principally III, IV, VI and VII) in 10-20% of
        patients; associated with a dramatic increase in complications from lumbar puncture
        and makes a poor prognosis
       Systemic Findings:
             Extracranial infection (e.g., URTI, sinusitis, OM, mastoiditis, pneumonia,
                 UTI)
             Arthritis is seen with N. meningitidis, less commonly with other bacteria
             Non-blanching petechiae and cutaneous haemorrhages are classic with N.
                 meningitidis but occurs with other bacterial and viral infections too.
             Endotoxic shock with vascular collapse is characteristic of severe N.
                 meningitidis infection
             Ultimately, altered mental status, from irritability to somnolence, delirium
                 and coma
       Infants:
             Bulging fontanelle (if euvolemic, consider dehydration if fontanelles are not
                 bulging)
             Paradoxical irritability (i.e., quiet when unmoved, crying when held)
             High pitched cry
             Hypotonia

Examine the skin over the entire spine for dimples, sinuses, nevi or tufts of hair, which may
indicate a congenital anomaly communicating with the subarachnoid space.

27.3 To be aware of the common organisms causing meningitis, including
parasitic causes
       BCS

The pathogens: (US figures)
- Neonates: Group B or D Streptococcus, E coli, Listeria monocytogenes and non-group B
   Streptococcus
- Infants/Children: Haemophilus influenzae B (48%), Strep. pneumoniae (13%) and N.
   meningitidis
- Adults: Strep pneumoniae (30-50%), HiB (1-3%), N. meningitidis (10-35%), gram
   negative bacilli (1-10%), Staph (5-15%), Streptococci (5%), and Listeria species (5%)

FUNGAL MENINGITIS                                      onset usu. slow (days – wks)
 Cryptococcus neoformans ( pt with                   capsulate yeasts (seen on India ink-
  cell-mediated immunity, e.g. AIDS pt)                 stained preps of CSF) & can be
 (also Coccidioides immitis)                           cultured
 invade blood from primary site in                    antigenic detection
  lungs  brain and meninges


 PROTOZOAL MENINGITIS                                  route of entry: olfactory tract &
   free-living amoebae (Naegleria &                    cribriform plate  acute or subacute
    Hartmanella spp)                                    meningitis
   multiply in stagnant freshwater in                 diagnosis: CSF (fresh wet sample)
    warm countries (lakes, swimming                    mortality is high
    pools)


 VIRAL MENINGITIS                                      milder, generally benign & self-
   very common                                         limiting
   headache, fever, gen. illness, less neck          complete recovery is the rule
    stiffness or asymptomatic                         bugs: mumps, polio, echovirus,
   CSF – clear, bacteria-free, cells                  coxsackievirus, HSV, Jap,
    mainly lymphocytes                                 encephalitis, HIV


Epidemiological facts and figures:
 Among pathogens, pneumococcal meningitis had the highest mortality (21%) and
   morbidity (15%), irrespective of time of presentation, BUT if severe neurological
   impairment is present on admission, the mortality goes up to 50-90%, irrespective of
   immediate treatment
 In neonates, males are afflicted 3:1; no sex preference in other age groups.
 Excluding meningococcal meningitis, those under five and over 60 years of age are at
   increased risk.
 Newborns are at highest risk for acute bacterial meningitis. Beyond the first month of life,
   the peak incidence is three to eight months of age.

Likely Causes of Meningitis According to Condition
Immunosuppression: Cryptococcus neoformans
                   Listeria monocytogenes

Basilar Skull Fracture = CSF Leak
                       Streptococcus pneumoniae
                       Haemophilus influenzae

Neurosurgery or CSF Shunt
                     Staphylococci
                     Gram Neg. Bacteria

27.4 To be aware of the pathophysiology of meningitis and the changes that
occur in the blood brain barrier in meningitis
       BCS

Pathology:
 3 main factors play a part in the development of bacterial meningitis: virulence of the
   strain, immune system of the host, and interactions between the bacteria and the immune
   system.
 Bacterial seeding usually occurs by haematogenous spread but typically local
   tissue invasion by bacteria naturally found in the nasopharynx appears to be a
   critical step, from there it leads to bacteremia and then crosses the BBB by any of
   four mechanisms (paracellular route, vesicular transport, bacterially-engineered
   pathways, or carrier-mediated transport).
 Rarely, infected contiguous structures invade via septic thrombi or osteomyelitic erosion
   and meningeal seeding may occur with a direct bacterial inoculate during trauma,
   neurosurgery or instrumentation.
 Meningitis in the newborn is transmitted vertically from colonized pathogens in the
   maternal intestinal or genital tract or horizontally from nursery personnel or caregivers at
   home.
 Once in the CSF, the relative lack of antibody, complement and WBCs allows the
   bacterial infection to flourish. Bacterial cell wall components initiate a cascade of
   complement- and cytokine-mediated events which results in at least three critical events:
         Increased permeability of the blood brain barrier (hence the increased protein in
            the CSF)
         Cerebral edema (hence the bulging fontanelles in infants), and
         Presence in the CSF of toxic mediators
   Replicating bacteria, increasing numbers of inflammatory cells, cytokine-induced
    disruptions in membrane transport and increased vascular and membrane permeability
    exacerbate the process and account for the characteristic changes in CSF cell count, pH,
    lactate, protein and glucose.
   Exudates extend throughout the CSF, particularly to the basal cisterns damaging cranial
    nerves (e.g., cranial nerve VIII involvement  hearing loss, a not-so-rare sequel of
    meningitis), obliterating the CSF pathways (causing obstructive hydrocephalus) and
    inducing vasculitis and thrombophlebitis (causing local brain ischemia).
   As intracranial pressure (ICP) continues to rise and brain oedema progresses, the CNS
    autoregulatory processes begin to fail. This pivotal event is thought to occur when the
    transient increase in cerebral blood flow (CBF) reverses and begins to decrease. This
    reduction in CBF has been shown to correlate with the patient's decreasing alertness and
    changes in mental status.
   Without medical intervention the cycle of decreasing CBF, worsening cerebral oedema
    and increasing ICP proceed unchecked. Ongoing endothelial injury may result in
    vasospasm and thrombosis, which further compromises CBF and may result in stenosis of
    large and small vessels. Septic shock may also impair CBF and the patient soon dies from
    multi-organ failure or from diffuse CNS ischemic injury.
   Fungal meningitis is thought to unfold in a manner similar but less acute than bacterial
    meningitis.

Virulence factors                        Bacterial Pathogen
                      N. meningitidis           H. influenzae             Strep. pneumoniae
Capsule                      +                          +                         +
IgA protease                 +                          +                         +
Pili                         +                          +                         -
Endotoxin                    +                          +                         -
Outer membrane proteins      ?                          +                         -

Haemophilus Influenzae
 Is an ubiquitous coloniser of the pharynx, existing in an encapsulated and an un-
   encapsulated form
 The encapsulated form dominates by secreting an antibiotic called haemocin that kills the
   other form
 Fimbriae and other adhesions on the surface of the H. influenzae mediate adherence of
   the organisms to the respiratory epithelium
 It also secretes a factor that disorganises the ciliary beating, and a protease that degrades
   IgA
 The capsule allows survival in the bloodstream, preventing opsonisation by compliment
   and phagocytosis by host cells
 In meningitis, a lipopolysaccharide endotoxin induces leukocyte chemotaxis and
   leukocytosis, and a cell wall peptidoglycan damages the vascular endothelium and
   disrupts the blood brain barrier

Prognosis and complications:
 Immediate:
   Septic shock, including DIC, coma with loss of protective airway reflexes, seizures (30-
   40% of children and 20-30% of adults), cerebral oedema, septic arthritis, pericardial
   effusion and haemolytic anemia (H. influenzae).
 Subdural effusions are reported in 39% of children aged 1-18 months with bacterial
   meningitis. Risk factors include young age, rapid onset of illness, low peripheral WBC
   count and high CSF protein.
    Seizures during the acute course of disease occur more commonly, although long-term
    sequelae in promptly treated subdural effusions is similar to uncomplicated meningitis.
   Delayed:
    Decreased hearing or deafness, other cranial nerve dysfunction, multiple seizures, focal
    paralysis, subdural effusions, hydrocephalus, intellectual deficits, ataxia, blindness,
    Waterhouse-Friderichsen syndrome and peripheral gangrene.


27.5 To be aware of the various CSF profiles in different types of meningitis
       BCS

Diagnosis                      Cells (per l)       Glucose        Protein       Opening
                                                    (mg/dL)        (mg/dL)       Pressure
Normal                         0-5 lymphocytes      45-85          15-45         70-180 mm
                                                                                 water
Purulent Meningitis            200-20000 PMN        Low ( <        High          Markedly
(bacterial- community          neutrophils          45)            ( > 50)       elevated
acquired)
Granulomatous                  100-100 mostly       Low ( <        High          Moderately
meningitis                     lymphocytes          45)            ( > 50)       Elevated
(mycobacterial, fungal)
Aseptic Meningitis, viral      100-100 mostly            Moderatel Normal to
                                                    Normal
or meningoencephalitis         lymphocytes               y High        slightly elevated
                                                         ( > 50)
Spirochetal Meningitis      25-2000 mostly   Normal or High            Slightly Elevated
                            lymphocytes      low         ( > 50)
Neighbourhood               Variably         Normal      Normal or Variable
reaction*                   increased                    High
*this can be mastoiditis, brain abscess, epidural abscess, sinusitis, septic
thrombus, brain tumour

27.6 To be aware of the role of investigations in evaluating meningitis
       BCS

    Lab
     FBC w/differential (important)
     Electrolytes (dehydration or SIADH) (important)
     Serum glucose (as baseline for determining normal CSF glucose)
     BUN/creatinine and LFTs (assess organ functioning and adjust antibiotic dosing)
     Coagulation profile and platelets in patients with chronic alcohol use, liver disease or
       if DIC suspected
     CSF: protein, glucose, gram stain, M/C/S (v. Important)
     Urine M/C/S: MSU (mid stream urine), or bladder tap in infants
     Blood cultures, not so important in acute cases, but may help correct treatment if you
       didn’t get it right at first!
     Swab cultures (from nasopharynx, skin lesions) as above!

Spinal Tap:
    Lumbar Puncture (LP)
    Elevated opening pressure correlates with morbidity/mortality in bacterial and fungal
       meningitis
    Tube #1 to hematology lab for cell count with differential
    Tube #2 to chemistry lab for glucose and protein
      Tube #3 to microbiology and immunology lab for gram stain, bacterial culture, AFB
       stain and TB cultures, India ink stain and fungal cultures, CSF VDRL and CSF
       cryptococcal antigen if indicated
      Tube #4 to hematology lab for a repeat cell count with differential

Imaging Studies:
    Contrast CT Head or MRI With Gadolinium:
    Indicated in patients with evidence of head trauma, altered mental status or focal
      findings, papilloedema and inability to fully assess fundi or neurologic status as an
      indication for CT prior to LP.
    In patients with suspected bacterial meningitis, obtain blood cultures and initiate
      treatment before imaging studies and LP.
    Results may be normal or demonstrate small ventricles, effacement of sulci and
      contrast enhancement over convexities
    Late findings include venous infarction and communicating hydrocephalus
    Rule out brain abscess, sinus or mastoid infection, skull fracture and congenital
      anomalies
    Chest X-Ray (CXR):
    As many as 50% of patients with pneumococcal meningitis also have evidence of
      pneumonia on an initial CXR.
    This association occurs in fewer than 10% of cases of meningitis caused by H.
      influenzae or N. meningitidis and in approximately 20% of meningitis caused by other
      organisms.

27.7 To be aware of the current treatment guidelines for meningitis in children
and the pharmacology of those drugs
       BCS

Treatment:
- Emergency care (ABCs, consider airway protection, IV access, crystalloids, electrolytes,
   oxygen, treat seizures with lorazepam/diazepam if present, etc...)
- Empiric antibiotics within 30 minutes of acute presentation.
- Lumbar puncture (consider whether previous antibiotics may mask findings; LP is very
   important, but empirical treatment can be life-saving; in subacute cases it is
   recommended that you try to get the LP before the antibiotics are given, but if this is
   likely to take more than 30 minutes, give the antibiotics first. If a focal neurological
   deficit is present, do a head CT before a LP).
- General measures include management of fever and pain, control straining and coughing
   and avoid seizures and systemic hypotension. In otherwise stable patients, head elevation
   and monitoring of neurologic status is usually sufficient.

Drugs:
A) Neonate: Group B, D streptococci; Enterobacteriaceae (e.g., E. coli), Listeria
   monocytogenes, give Ampicillin and Cefotaxime or Ampicillin & Gentamicin

B) Infant: the same bugs as above + Strep. Neisseria & HiB- dexamethasone: 1st dose 15-20
   minutes before 1st dose antibiotics. plus 1-Cefotaxime or 2-Ceftriaxone and Ampicillin
   or: 3-Chloramphenicol and Gentamicin

C) Older infants & young children: S. pneumoniae, N. meningitidis, HiB- dexamethasone:
   1st dose 15-20 minutes before 1st dose antibiotics.+ Cefotaxime or Ceftriaxone (consider
   vancomycin if drug resistant Strep. Pneumoniae)
D) Older children and adults: - S. pneumoniae, N. meningitidis, Listeria monocytogenes -
   Cefotaxime or Ceftriaxone, the same as above if DR Strep.pneumoniae present

E) Old people - S. pneumoniae. Rarely coliforms, H influenzae, Listeria, P. aeruginosa, N.
   meningitidis - Cefotaxime or Ceftriaxone and Ampicillin - If DRSP replace ampicillin
   with vancomycin.

F) Immunosuppressed - S. pneumoniae. Rarely coliforms, H influenzae, Listeria, P.
   aeruginosa, N. meningitidis, cryptococcus, M. tuberculosis, syphilis, HIV aseptic
   meningitis; Cryptococcal: Amphotericin B

G) Post traumatic or surgical meningitis - S. pneumoniae, S. aureus, coliforms, P. aeruginosa
   - Vancomycin and Ceftazidime

27.8 To describe the immunisation protocol for children in Australia, and the
public health implications of a disease outbreak, eg. meningitis
       DC


27.9 To develop skills in the assessment of the febrile child
       ICS&CRP

Stuff on Evaluation & Differential Diagnosis Of Febrile Child
 Fever  rectal temp > 38 C or oral temp > 37.5 C or axillary temp > 37 C
 Average body temp (orally) is 37 C but this fluctuates diurnally (36.4 early morning 
    37.5 late afternoon)
 Mild elevations caused by : exercise, excessive clothing, hot baths, hot weather, hot food

Causes of Fever
 normal response of body to infections, most fevers in children due to viral, some bacterial
 the usual fevers (37.8 - 40) that all children have at times are not harmful
 most "fevers" that stay under 38.3 are due to hot weather or overdressing

Expected Course of Fever
 most fevers from viral illnesses range between 38.3 - 40  C and last for 2-3 days
 in general the height of a fever does not relate to the seriousness of the illness; how sick
   the child is, does
 fever causes no symptoms per se until it reaches 38.9 or 39.4 
 fever can cause harm to the brain when it reaches 41.7
 about 4% of children with fevers experience a febrile convulsion which is generally
   harmless

Guidelines for evaluating children with fever
I.     Further immediate evaluation is necessary if:
       - the child is < 2 months old
       - fever > 40.1
       - child is crying inconsolably or whimpering
       - child cries when moved or otherwise touched by parent
       - child is difficult to awaken
       - neck is stiff
       - purple spots are present on the skin
       - breathing is difficult and no better after nose is cleared
       - child is drooling saliva and is unable to swallow
       - a convulsion has occurred
       -   the child looks or acts very sick

II.    Further evaluation within 24 hours is necessary if:
       - child is 2-4 months old (unless fever has occurred within 48 hours of DPT
           vaccination & there are no other serious symptoms)
       - fever is between 40 - 40.1 (especially if the child is under 2 y.o.)
       - during urination burning or pain occurs
       - fever has been present for > 24 hours without obvious cause or locus of infection

III.   Further evaluation during normal office hours is necessary if:
       - the fever went away for >24 hours and then returned
       - the fever has been present > 72 hours
       - the child has a history of febrile seizures



Evaluation of the febrile infant and "outpatient" bacteremia
Essentials of diagnosis
        infant < 2 y.o. with fever
        no focal infection found on physical examination

General considerations
      - young children are at greater risk of infection due to immunological immaturity
      - in first few weeks multiple defense mechanisms are immature
      - after several months transplacental IgG is lost and baby is very susceptible to
          encapsulated bacteria e.g. pneumococcus, meningococcus, Haemophilus
          influenzae B
      - infants < 2y.o. with a rectal temp. > 39 and no obvious focus of infection have a
          3-5% incidence of occult bacteremia
      - the height of the temperature does not correlate well with the illness; infants < 3
          months old may be bacteremic even though they have a low grade fever and
          appear nontoxic on examination. This is one reason why more tests and
          hospitalization are indicated for very young infants.
      - Causes of occult bactermemia (in USA) : pneumococcus (50-80 %), H. influenzae
          type b, Meningococcus, Salmonella, E. coli, and other enteric bacteria. Infants <
          3-4 months old: group B strepts and Listeria are possible; Herpes (rare but may
          be linked to maternal history); Other viruses which cause fever and few
          symptoms include the enteroviruses; influenza and adenoviruses usually are
          accompanied by respiratory symptoms

Clinical findings
(a) History
        - many infants with viral infections have household contacts with febrile illness
        - infants with UTI usually have no significant exposure history
        - since infants with mild viral infections can also be bacteremic not too much
            emphasis should be placed on household contacts

(b) Symptoms and signs
       - careful examination should detect focal infections
       - those notoriously hard to diagnose by physical examination include: bacterial
          pneumonia, sinusitis, UTI, and meningitis
       - pneumonia may be present with only mild tachypnea on normal auscultation;
          preceding or concurrent respiratory signs (rhinitis, cough) are usually present
        -   UTI may present with vomitting or mild abdominal discomfort, but often have no
            abnormal physical findings
        -   Meningitis may present only with irritability; the younger the infant the less
            reliable the physical examination
        -   Because temperature may be easily treated with antipyretics the height of the
            temperature does not corelate with the cause of the underlying illness
        -   Bacteremic children over 3 months of age are more likely not to make eye-
            contact with the examiner than non-bacteremic children

(c) Lab & imaging investigations
       - the diagnostic test for bacteremia is blood culture
       - only the total and differential leukocyte counts have practical application
           (incidence of bacteremica increases as leukocyte count increases). 66% of
           bacteremic children have a total leukocyte count > 15000 /  L
       -    lumbar puncture is advised on all children < 3 months old, and on most infants 3-
           12 months old with no focal findings. In older children the need is based on the
           degree of irritability and toxicity, but is strongly recommended for those who are
           still febrile despite anitbiotics since they may have partially treated bacterial
           meningitis
       - urine analysis is the next most important test. Voided specimens, especially via a
           bag, are often unreliable. A catheterised or suprapubic aspirate is preferred. A
           gram stain is the best rapid test to exclude bacteremia
       - CXR is part of the complete evaluation to exclude pneumonia

27.10 To develop skills in the Lumbar puncture, and suprapubic aspiration in
an infant
                                                                   ICS&CRP
Q1.What layers do you puncture when doing an LP?
A1.
 Skin and underlying fat
 Supraspinous ligament
 Interspinous ligament
 Ligamentum flavum
 Epidural space
 Dura mater
 Subdural space
 Arachnoid membrane
 Subarachnoid space containing CSF

Q2. Why is the patient is positioned on his side in full lumbar flexion.
A2. Flexion is to maximise the distance between the spinous processes and lying down is to
minimise pressure on the discs.

Q3. Between which vertebrae would you insert the needle? Explain your answer.
A3. The needle is inserted in the midline between the spinous processes of L3 and L4. This is
in order to miss the spinal cord, and the spinal cord/conus medullaris ends at L1/L2.

Contraindications                                 -    GCS of 8 or less
- suspected cerebral mass lesion: ataxia          -    Status epilepticus
   may be due to posterior fossa                  -    CVS instability
   pathology                                      -    Focal neurological signs
- lead encephalopathy                             -    Coagulation problems:
- Reye syndrome                                        thrombocytopenia less than 50 x 109/L
- Signs of raised ICP                             -    Overlying skin infections
Technique
- attention to aseptic technique is critical: hand washing, sterile gloves and mask
- experienced assistant is essential: young child firmly held in the lateral position; spine
   must be flexed and movement must be minimal
- surgical preparation and draping of the skin
- inserting the needle: L3 to L4 disc space at the level of the iliac crests; check that the
   stylet of the needle is secure; kneel on a pillow so that the child’s spine is at your eye
   level; insert perpendicular to the skin with the bevel facing towards the patient’s head;
   pause after breaking the skin to re-establish midline; progress needle aiming for the
   umbilicus; needle should proceed smoothly until a distinct “pop” is felt as it passes thro’
   the dura; may have to twirl needle to establish CSF flow; collect 10 drops of CSF in each
   of 3 tubes
- failure is usually due to poor needle placement: check for correct position of the patient;
   withdraw the needle, recheck position and try again; may try one space higher except in
   infants

Practice Points
- most awake patients with any meningitic symptoms would normally require a LP; a
   recent negative LP even 6-12 hrs previously should not influence the decision to perform
   a LP in a febrile child where the cause may be meningitis e.g. normal CSF from LP on
   admission does not influence the decision to repeat the procedure next day if the child
   deteriorates
- CAT before LP may not pick up severe rise in ICP
- Local anaesthetic is not normally used when the LP is diagnostic for meningitis; time
   delays associated with the administration of anaesthetic are unacceptable in an infant who
   may have meningitis
- Pressure measurement is difficult in infants: rate of flow is an unreliable guide to
   pressure

Alterations in Quality of Tap
- dry tap, ie. no fluid
     - mostly due to incorrectly placed needle
     - sometimes due to pathologically obliterated subarachnoid space
         - compressive lesion of spinal cord or chronic adhesive arachnoiditis
- bloody tap
     - can be due to penetration of meningeal artery or subarachnoid hemorrhage
     - to distinguish, centrifuge sample immediately
         - if supernatant clear probably penetrated meningeal artery
         - if supernatant xanthochromic probably subarachnoid
if penetrated meningeal artery, CSF progressively become more clear in successive tubes (not
so for subarachnoid)

Complications
- complications are rare: raised ICP; transtentorial herniation; headache; spinal block;
  nerve root irritation
- traumatic tap: due to puncture of a vein behind the theca; can often be avoided if needle
  insertion stops when a “pop” is felt as the needle passes through the theca; bloody CSF is
  still useful for culture growth; CSF may clear for the second or third collection tube

Side Effects
- after lumbar puncture keep patient in comfortable recumbant position before rising
- main side effect is headache
    - occur in 5-10% of patients
   -   due to persistent leakage of CSF (this is also the presumed cause of cases of coning,
       that occurs some time, ie. usually ½ - 4 hours, after the procedure)
   -   usually begins 12-48hrs after procedure
   -   can last for several days to 2wks
   -   usually made worse by being upright, + better by lying flat

Suprapubic Aspiration
 Safe and effective way to collect urine especially in babies who are acutely ill or if
   contamination on bag collection is suspected.
   - Bladder is an abdominal organ till 18 months of age.
 Preparation – Perform 1 hour after last void to ensure adequate volume. Occlude penile
   urethra or be prepared to get wet.
 Position patient in supine “frog” position
 Use 23G needle on a 5mL syringe 1-2 cm above symphysis pubis. Angle 10-20
   caudally from vertical & insert to 2cm.
 Withdraw while continuously aspirating with the syringe
 If no success, try inserting at true vertical.
 If needle is inserted too deeply, bowel contamination may occur.

27.11 To develop skills in obtaining an intravenous line, arterial blood gas
sample and blood cultures from an infant


27.12 To describe the causes and implications of low Australian infant
immunisation rates, and the related ethical, public health and policy issues in
responding to them
                                                                       DC/EPPD
Ethics stuff from Mal “Practice” Parker’s Essay
Incentive / coercion:                        assistance
 Federal Gov’t 7-point plan from            ? Punitive - economic bias?
   1998                                                   - incentive for
 Incentives to doctors                                      supporters
 divisional activities / PIP funding                     - vs common good
 linked to C’th benefits eg childcare


Normal consent - disclosure                               -   risks more “real” than
- information provision prior to                              advantages
   vaccination                                            -   perceived low risk of illness,
- discussion of parental concerns                             even if not immunised
- dismissive attitudes reduce imm’n                       -   parents risk-averse in relation
   rates                                                      to own children
- perception of risks

Perception of risks
- Risks more “real” than advantages
- risks more visible than disease when vacc rates high
- perceived low risk of illness, even if not immunised

Consent and Rights- Consent for                   -   adult’s autonomy vs right of child to
children                                              protection
- on behalf of child                              -   ? case for compulsory vaccination to
- not analogous to normal consent                     prevent harm
- risk perception issues
Individuals and the community                    -   failure to immunise:
- Herd immunity - high vaccination               -   failure to benefit or direct harm ?
   rates                                         -   Arguably a harm:
- High vacc rates - unvaccinated benefit                  - if protection seen as basic
   without risks                                              right
- Herd immunity - type of common                          - choosers but non-responders
   good                                                   - excluded on medical grounds
- ? obligation to contribute to c. good                   - excluded by access /
- ? failure to immunise - harm to others                      disadvantage
- direct harm >> failure to benefit

Paradoxes- Self-interest position:
   - everyone vaccinated except me
- if too many believe this, I (& they) will be worse off
- so good reasons (for both self & others) compared to moderate self-interest
- if non-immunised group small - herd OK
- costs imposed esp for eradicable disease
- case for compulsion
- if same imm’n rates achievable w/o compulsion, avoid compulsion

Common Side Effects of Immunisation
Most only last a short time and the child recovers w/o any problems
- child needs comforting, and side effects can be ed with a few simple guidelines:

         Vaccine                Common Reactions                        What to Do
DTP                            low grade fever being               give extra fluids to drink
(diphtheria-tetanus-pertussis    grizzly, unsettled and             do not overdress the
vaccine - triple antigen)        generally unhappy                   baby if hot
                               soreness, swelling and              tepid sponge or tepid
                                 redness in the area                 bath if hot
                                 where the injection was            a cold, wet cloth on the
                                 given                               sore spot at the injection
                                                                     site will help relieve
                                                                     some discomfort
                                                                    give paracetamol to
                                                                     lower fever if needed
MMR                             5-12 days after
(measles-mumps-rubella          immunisation, and lasting
vaccine)                        less than 48 hours:
                                 low grade fever faint
                                    rash (not infectious)               AS FOR DPT
                                 head cold /runny nose
                                 cough / puffy eyes
                                 swelling of the facial
                                    glands may occur (after
                                    ~ 3wks)
OPV                              very rarely any                   Rx not usw needed
(oral poliomyelitis vaccine)        reactions
Hib vaccine                      Reactions uncommon,
(Haemophilus influenzae            but include low grade
type b)                            fever; soreness, redness           AS FOR DPT
                                   and swelling in the area
                                   where the injection was
                                   given
Hepatitis B vaccine              Reactions uncommon,
                                   but include low grade
                                   fever; soreness, redness
                                   and swelling in the area           AS FOR DPT
                                   where the injection was
                                   given ; nausea, feeling
                                   unwell and joint pain
N.B. if reactions are severe and persistent or if you are worried about your child,
contact your doctor or hospital

				
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