Lumbar Puncture

Lumbar Puncture

Presenters: Dr Khozya D. Zyambo

Dr Grace Chingo

Moderator: Dr Somwe

1. When not to a lumbar puncture.2. The role of lumbar puncture in suspected

central nervous system (CNS) infection - a disappearing skill.

3. When to do a lumbar puncture (LP).4. Lumbar puncture following febrile convulsions.5. Bulging fontanelle in febrile infants: is lumbar

puncture mandatory?

Presentation Outline

When not to do lumbar puncture.

D P ADDYDudley Roa4 Hospital,Birmingham B18 7Q

Arch Dis Child 1987 62: 873-875

It may seem a strange principle to enunciate as the very first

requirement in a Hospital that it should do the sick no harm.

FLORENCE NIGHTINGALENotes on Hospitals, 1859

There are three reasons for not performing any clinical investigation:

When its inconvenience, discomfort, or expense is disproportionate to its clinical value

When it is unlikely to produce clinically useful information

When it is unjustifiably dangerous

3 Critical Points of arguments

The only urgent indication for lumbar puncture

is the suspicion of bacterial meningitis.

A decision to do a LP is easy, however, compared with deciding whether a lumbar puncture is or is not too dangerous.

In September 1985, the British Medical Journal

published a letter from Dr J R Harper describing a child with meningococcal meningitis whose condition deteriorated rapidly two hours after lumbar puncture and who subsequently died.

He asked whether it was permissible to avoid LP if the clinical diagnosis of meningitis seemed clear.

Lumbar puncture in meningitis

Four expert opinions

Two (a paediatrician and a physician) accepted that if there was a clear clinical diagnosis treatment should be given and lumbar puncture avoided, and

Two (a paediatrician and a microbiologist) thought that diagnostic lumbar puncture should be routine.

LP in meningitis cont’d

Reasons for routine LP are to

Confirm the diagnosis, Identify the organism, Test for antibiotic sensitivities, Rationalise the treatment of contacts in the case of

meningococcal or haemophilus meningitis.

Blood culture identified the organism in over 80% of the cases due to Streptococcus pneumoniae or Haemophilus influenzae at the Birmingham Children's Hospital, but failed to do so in over half of the cases due to Neisseria meningitidis

What important diagnosis might be missed by not doing a lumbar puncture?

Why do a lumbar puncture?

The main reason for not doing a lumbar puncture

for suspected meningitis is the fear of transtentorial or transforaminal herniation or coning.

Can we estimate the risk and can we define the circumstances in which the risks outweigh the benefits?

There is evidence that coning may contribute to the outcome in an appreciable number of deaths from bacterial meningitis, perhaps in 30% or more cases.

Reasons for not doing a lumbar puncture

Horwitz et al examined the records of 302

children admitted to hospital in Cleveland, Ohio, with bacterial meningitis.

Coning was suspected clinically in 27. Ten children died, three of whom had had signs of coning. 27% of the survivors had severe neurological damage.

Reasons for not doing a lumbar puncture,

cont’d

Slack found evidence of coning in six of the 90

deaths from meningococcal infection in all age groups in England and Wales in 1978. One of the patients had not had a lumbar puncture, but in three meningococcal meningitis had been diagnosed before lumbar puncture.

In Glasgow, at least 5/11 deaths in 248 children with bacterial meningitis were thought to have been associated with brain swelling and coning.

Reasons for not doing a lumbar puncture,

cont’d

To do LP in a very young child with a febrile convulsion

or for one who does not rapidly recover and for a child with an acute feverish illness when the diagnosis is uncertain but meningitis is a possibility.

To consider treatment without LP whenever the diagnosis of meningitis seems clear and the child is seriously ill, has a typical purpuric rash, has fundoscopic evidence of raised intracranial pressure, has impaired consciousness, has other signs of incipient coning, or has been ill for several days.

The debate will continue, but any decision about lumbar puncture must be made by an experienced doctor.

Conclusion: Personal Approach

The role of lumbar puncture in suspected

CNS infection—a disappearing skill?

R Kneen, T Solomon, R AppletonArch Dis Child 2002 87: 181-183

When to do a lumbar puncture

F A I Riordan, A J CantArch Dis Child 2002 87: 235-237

What are the benefits of lumbar puncture in

suspected meningitis?

What are the contraindications to lumbar puncture?

Should lumbar puncture be performed after a febrile convulsion?

How is meningitis diagnosed and treated if an early lumbar puncture is not done?

Critical questions

LP confirms or excludes bacterial meningitis Initial Gram staining of cerebrospinal fluid (CSF)

reveals an organism in 68–80% of cases of meningitis, allowing appropriate choice of antibiotics. (Feigin RD, Pearlman E. Bacterial meningitis beyond the neonatal period).

Allows identification of uncommon pathogens, such as mycobacteria and fungi.

Enteroviral meningitis can be diagnosed by CSF PCR, allowing for the discontinuation of antibiotics and early discharge.

Benefits of lumbar puncture in suspected meningitis

It is rare for microscopy of CSF obtained at LP to be

normal, and a pathogen to be grown later. (May occur in meningococcal meningitis up to 8%)

The classic non-blanching rash sign is not always a result of meningococcal disease.

Unpublished study by Riordan, showed that of 63 children with meningism and a “meningococcal” rash, 51 had meningococcal disease, 10 had viral illnesses, and two had other types of bacterial meningitis.

Benefits of lumbar puncture in suspected meningitis,

cont’d

Thinking of alternative less invasive test,

blood cultures are positive in only 50% of neonates with meningitis. (Shattuck KE, Chonmaitree T.; Franco SM, Cornelius VE, Andrews BF)

Negative blood cultures thus cannot exclude meningitis in an ill neonate.

Benefits of lumbar puncture in suspected meningitis,

cont’d

Cerebral herniation:

Symptoms and signs occur in 4–6% of children with bacterial meningitis

Accounts for 30% of deaths in bacterial meningitis, independent of LP.

Case series have shown a temporal association between lumbar puncture and herniation

Focal neurological signs especially in diseases that mimic meningitis, e.g. tumour, abscess, or intracranial haemorrhage, pose increased risk of herniation (Richards PG, Towu-Aghanste E. Dangers of lumbar puncture)

Contraindications to lumbar puncture

The presence of focal signs, depressed

consciousness, or failure to respond to treatment are thus an indication for an urgent CT scan to exclude these conditions

Most children with bacterial meningitis and clinically suspected raised intracranial pressure have normal scans. Heyderman RS, Robb SA, Kendall BE, et al. Does computed tomography have a role in the evaluation of acute bacterial meningitis?

Contraindications to lumbar puncture, cont’d

Cardiorespiratory compromise.

Excessive flexion of the trunk and neck during lumbar puncture may produce hypoxaemia in neonates

Infection in the area the needle will traverse to get CSF or signs of a bleeding disorder are also said to be contraindications (based on single case reports).

NB: A delayed lumbar puncture can confirm the diagnosis of meningitis, since the cellular and biochemical changes remain in the cerebrospinal fluid up to 44–68 hours after the start of antibiotic treatment (Feigin RD, Pearlman E. Bacterial meningitis beyond the neonatal period).

Contraindications to lumbar puncture, cont’d

Carroll and Brookfield’s review and another

evidenced based review suggest that the probability of bacterial meningitis presenting as fever and seizure is 0.4–1.2%.

Signs of meningitis (meningism, petechiae, coma) are usually present but may be absent in 30%.

Children with meningitis but no meningism either have complex seizures (prolonged, partial, or multiple) or symptoms suggestive of meningitis (unwell for three days or more, vomiting or drowsy at home, seen by a doctor in the previous 48 hours).

Should lumbar puncture be performed after a febrile

convulsion?

Children with simple febrile convulsions

and no symptoms or signs of meningitis are highly unlikely to have bacterial meningitis (Offringa M, Moyer VA. Evidence based management of seizures associated with fever, BMJ 2001;323:1111–14.).

Should lumbar puncture be performed after a febrile convulsion?

Cont’d.

Early LP rapidly confirms or excludes bacterial meningitis in most

cases and should be performed when meningitis is suspected unless there is a specific contraindication.

If early LP cannot be done, Delayed LP can be done within 72 hours. Collect blood culture and do meningococcal PCR (Causative organism

will not be identified in 20–50% of cases of bacterial meningitis). Meningitis rarely presents as a simple febrile convulsion, but complex

seizures, a prolonged illness, or toxicity which are all indications for lumbar puncture.

With increasing antibiotic resistance, paediatricians managing meningitis will have to decide between using empirical broad spectrum antibiotics (potentially encouraging further antibiotic resistance) or early LP as the best method to culture the causative organism. (McMaster P, McIntyre P, Gilmour R, et al. The emergence of resistant pneumococcal meningitis—implications for empiric therapy. Arch Dis Child 2002;87:207–11).

Conclusion

Lumbar puncture following febrile

Convulsion

W Carroll, D BrookfieldArch Dis Child 2002 87: 238-240

Article examined existing guidelines, practice,

and the available evidence of the value (and potential risks) of lumbar puncture following a febrile convulsion.

LP, a painful pointless procedure?

Most recently available national guidelines for the

management of convulsions with fever in the United Kingdom were issued in 1991.

The guidelines suggested that doctors should “almost certainly” perform a lumbar puncture in children under 1 year, even in the absence of signs of meningitis.

They also suggested that “an experienced doctor may decide on clinical grounds that a lumbar puncture is unnecessary”

Existing Guidelines

The American Academy of Pediatrics published

its “practice parameter” in 1996.

It too, fell short of recommending lumbar puncture for all children under 12 months, but suggested that lumbar puncture be “strongly considered”, because the clinical signs and symptoms of meningitis may be subtle.

Existing Guidelines

A study in the 1970s showed that nearly all children

(96%) received a lumbar puncture following their first febrile seizure.

By the early 1980s this number had fallen to two thirds (67%), and by the early 1990s reported rates for lumbar puncture following a febrile seizure had fallen to a mere 16%.

The most recent large scale survey of practice was conducted in the mid-1990s in the Mersey region which revealed a wide variation in lumbar puncture rates between hospitals but showed an overall rate of 11.5%.

Historical practice

A retrospective study at the centre where the

authors of this article come from showed a dramatic fall in the number of lumbar punctures performed, from 62% in 1989 to nil in 1998.

A survey of practice across the United Kingdom by paediatric registrars from 100 randomly selected hospitals within the British Isles were contacted by telephone and given a clinical scenario consistent with a simple first febrile convulsion in infancy and were asked whether they would or would not perform a lumbar puncture.

Changes in practice

The results revealed that 46% elected to

perform a lumbar puncture and 54% elected to observe the child.

Interestingly the presence (or knowledge of) local guidelines had little effect on the likelihood of electing to perform a lumbar puncture.

Changes in practice, cont’d

A thorough literature review identified 15 “first world”

papers that contained relevant data (see table below).

Two things are immediately obvious from these data

1. The low incidence of bacterial meningitis as a cause for febrile convulsions. The overall incidence of bacterial meningitis being 0.8% (95% CI 0.73 to 0.88%)

2. Change in reported incidence over time. The incidence of bacterial meningitis as a cause of febrile convulsions has fallen to 0.23% (95% CI 0.0 to 0.46%) in the 1990’s.

Systematic Review

Bacterial meningitis in the absence of associated

signs (irritability, lethargy, and/or bulging fontanelle) is extremely uncommon.

In papers where this information was recorded, only four out of a total of 30 cases of bacterial meningitis had no associated meningeal signs at the time of presentation.

In a further three cases, the presence or absence of signs of meningitis were not documented.

All the seven “non-meningitic”children underwent lumbar

puncture at the time of admission and 3/7 had normal CSF.

After 36–48 hours, the 3 children underwent further deterioration and developed obvious signs of meningeal irritation.

Subsequent lumbar puncture showed one case of pneumococcal and two cases of meningococcal meningitis.

In all cases, the normal CSF resulted in a delay in antibiotic treatment and one child died.

Although age is not documented in two of the seven cases, four of these children were older than a year and only one child was definitely in the 6 month to 1 year age range.

In a recent multicentre study in the UK, one sixth of children seen at hospital

following a febrile convulsion were between 6 months and 1 year of age (16.7%, 95% CI 16.2 to 17.2%).

Extrapolation of these data shows an estimate of 685 children in the studies were infants and a calculation of a maximum incidence of occult meningitis in infancy following a febrile convulsion of 0.44% (95% CI 0% to 0.88%).

Even this figure is probably an overestimate, assuming that where it is not documented, children are infants with no signs of meningitis but, in any case, this illustrates the very low probability of lumbar puncture changing treatment decisions.

In an infant with no signs of meningitis following a febrile convulsion, over 200 lumbar punctures would have to be performed to detect one case of unsuspected meningitis.

One in six children who attend hospital with a

febrile convulsion will be under 1 year of age and will undergo LP due to the perceived high risk of occult bacterial meningitis in this age group. Is this justified?

The available data would suggest that it is not.

The risk of bacterial meningitis in the absence of other clinical signs is extremely small (less than one in two hundred), even in this age group.

Discussion

The belief that bacterial meningitis in infancy commonly

presents with fever and seizures alone stems from one small study conducted over 30 years ago, Samson JH, Apthorp J, Finley A. Febrile seizures and purulent meningitis. JAMA 1969.

The causative organism in all these children was H influenzae which historically was the commonest cause of bacterial meningitis in infancy.

However, since the introduction of the conjugate Hib vaccine this organism is now an extremely uncommon cause of disease in the UK.

Furthermore, early lumbar puncture is not a

sensitive predictor of meningitis in this group of patients, missing over 40% of cases if performed routinely on admission to hospital

It is clear from the available data that lumbar puncture

following a febrile convulsion is unnecessary and unjustified in an infant without signs of meningitis.

In an apparently well child who subsequently deteriorates, a previously normal lumbar puncture does not rule out bacterial meningitis.

Observation and regular review by the nursing and medical staff in the first few hours after the convulsion, with an emphasis on examination for signs of meningitis, is more likely to detect children with bacterial meningitis and avoids the need for a painful and invasive procedure.

Conclusion

Bulging fontanelle in febrile infants: is lumbar

puncture mandatory?

S Shacham, E Kozer, H Bahat, Y Mordish, M Goldman

Arch Dis Child 2009 94: 690-692 originally published online June 15, 2009.

Akpede et al1 reported that the only signs that were significantly

associated with bacterial meningitis in 94 infants were a bulging fontanelle and focal seizures.

Berkley et al demonstrated that a bulging fontanelle, neck stiffness, cyanosis, impaired conscious state (including lethargy or agitation), seizures outside the ‘‘febrile convulsion age’’ and focal seizures were predictors of bacterial meningitis in 91 infants.

The presence of one or more of those indicators had a sensitivity of 79% and specificity of 80% for bacterial meningitis.

Independent indicators of the absence of meningitis were the absence of a history of fever, a history of diarrhoea or a positive malaria slide.

To determine the aetiologies and clinical

characteristics of infants with fever and a bulging fontanelle.

Study Objective

A retrospective cohort study.

The medical records of all febrile infants with a bulging fontanelle who underwent a lumbar puncture from January 2000 to February 2008 in Assaf Harofeh Medical Centre, a university affiliated hospital in central Israel, were identified.

Infants aged 3–18 months presenting with fever (rectal temperature >38.0uC) and a bulging fontanelle were eligible for inclusion in the study.

Infants younger than 3 months were excluded due to the different approach to fever in this age group.

Methods

Bacterial meningitis was defined by bacterial

growth in the CSF culture.

Aseptic meningitis was defined by CSF leucocyte count above 5 cells/mm3 with a negative gram stain and without bacterial growth on culture.

153 patients met the inclusion criteria. Cerebrospinal fluid pleocytosis was found in 42 cases

(27.3%), including one case of bacterial meningitis (0.6%). Appearance on admission was described as good to

excellent in 113 (73.8%) infants, none of whom had bacterial meningitis.

32 had aseptic meningitis and 17 had other bacterial disease (pneumonia, acute otitis media, pyelonephritis, bacteraemia, shigella or salmonella gastroenteritis).

All the 17 had, upon admission, symptoms, signs, laboratory tests or imaging studies suggesting a bacterial aetiology.

Results

Other lumbar puncture findings were normal CSF in 103

cases (67.3%) and bloody tap without growth in the CSF culture in eight cases (5.2%).

The history of the infant with bacterial meningitis was positive for vomiting, restlessness and was described as septic looking and lethargic.

Her blood count revealed leucopenia (1.46103/mm3) and neutropenia.

CSF culture was positive for Streptococcus pneumoniae.

Other leading diagnoses were aseptic

meningitis (26.7%),

upper respiratory tract infection (18.3%), viral disease NOS

(15.6%), roseola infantum (8.5%) and acute otitis media (6.5%)

This large cohort of febrile infants with a bulging

fontanelle, only one out of 153 infants had bacterial meningitis.

None of the patients who appeared well had bacterial meningitis.

We cautiously suggest that in an infant who appears well and in whom there is no other indication for prompt antibiotic treatment, it is reasonable to observe the infant and withhold a lumbar puncture.

Prospective studies should be carried out in the future to confirm this approach.

Conclusion