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How to Treat
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INSIDE
Asplenia vs
hyposplenism
Presentation
Diagnosis
Overwhelming
post-splenectomy
infection
Management
Special
considerations
the authors
DR Denis Spelman
deputy director, department
of infectious diseases; head,
Microbiology and Victorian Spleen
Service, the Alfred Hospital,
Melbourne, Victoria.
Penelope Jones
manager, Victorian Spleen
Service, department of infectious
diseases, the Alfred Hospital,
Melbourne, Victoria.
Asplenia and
hyposplenism
ASSOCIATE PROFESSOR
Allen Cheng
infectious diseases physician,
department of infectious diseases,
the Alfred Hospital; deputy head,
department of epidemiology and
preventative medicine, Monash
University, Melbourne, Victoria.
Introduction
THE spleen is the body’s largest lymphatic organ. It functions to remove
old and damaged blood cells from
the circulation and to filter organisms from the blood circulation. The
spleen is an important site of anti-
body production. The absence of
a spleen (asplenia) or a poorly functioning one (hyposplenism) results
in a significant risk of overwhelming post-splenectomy infection or
sepsis, a condition that has a reported
mortality of over 50%.
The risk of overwhelming postsplenectomy infection in an individual
with asplenia or hyposplenism is lifelong. Strategies to prevent this condition have been developed, and are
effective and potentially life-saving.
However, cases and deaths continue
to occur because advice on preventive
strategies is not given or is incomplete, or because the patient has not
acted on the advice or has forgotten it.
cont’d next page
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Australian Doctor
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13 September 2013 | Australian Doctor |
23
How To Treat – Asplenia and hyposplenism
Asplenia vs hyposplenism
Asplenia
ASPLENIA is usually due to a condition requiring splenectomy. The
reasons for splenectomy at our
registry show that trauma (see figure 1) is the most common cause
of splenectomy (34% of cases).
This is followed by haematological
disorders including malignancies
(32%). Non-traumatic and nonhaematological
intra-abdominal
surgery make up 24% of the registry
including incidental or ‘unplanned’
splenectomy (eg, spleen injury at
time of laparoscopic banding) and
planned splenectomy (eg, planned
removal of a spleen that is attached
to a bowel cancer).1
Trauma is the most
common cause of
splenectomy (34% of
cases).
Figure 1.
Splenic
angiogram
demonstrating
blunt traumatic
injury to the
upper pole with
intrasplenic
extravasation
and false
aneurysms.
Causes of asplenia or hyposplenism
Trauma
Causing: unstoppable bleeding, abnormal function, damage to the spleen
Medical conditions
Idiopathic thrombocytopenic purpura
Thalassaemia
Spherocytosis
Spontaneous rupture
EBV-associated splenomegaly
Medical conditions associated with functional hyposplenism
Spontaneous rupture in pregnant woman
Unknown cause
Splenic infarction
Caused by emboli (eg, in atrial fibrillation or septic emboli)
After gastric sleeve operation due to interruption of blood supply to spleen
Autosplenectomy (eg, sickle-cell disease)
Congenital absence of spleen
B
orn without a spleen or with congenital cardiac abnormalities that render
spleen non-functioning
Specific medical syndromes associated with congenital
asplenia or hyposplenism
Heterotaxy syndrome
Ivermark (asplenia) syndrome
Isolated congenital asplenia
Coeliac disease
Congenital asplenia, either as
a part of specific medical syndromes, or uncommonly as an
isolated asplenia, can occur and
may warrant screening of family
members.
Hyposplenism
Hyposplenism describes a spleen
that is not absent but functions
poorly and affects the individual
similarly to asplenia. There are several medical conditions that predispose to functional hyposplenism (see
box, right).
Inflammatory bowel disease such as ulcerative colitis
Haemoglobinopathies such as sickle cell anaemia can be associated with
splenic auto-infarction.
Infiltration or replacement of splenic tissue in such conditions as multiple
myeloma. In this setting it would be important to know whether recurrent
bacterial infections are due to functional hyposplenism or another medical
predisposition
Bone marrow transplantation: functional hyposplenism may complicate up to
40% of allogeneic bone marrow transplants especially in the presence of graft
vs host disease
HIV infection
Post-therapeutic splenic irradiation for malignancies
Sarcoidosis
Presentation
A PATIENT with asplenia or hyposplenism may present to the GP in
several ways. They may present
requesting routine post-splenectomy follow-up after recent hospitalisation.
A patient with known past splenectomy may present:
• Unwell with fever.
• Following a dog or other animal
bite, with or without clinical evidence of infection.
• As confused and brought in by
friend or relative.
• With plans to travel overseas,
requesting advice concerning
travel vaccinations and antimalarial medications.
• With the plan for future abdominal surgery or dental work,
seeking advice for what extra precautions may be required in view
of their asplenic state.
A patient who is undergoing a
planned splenectomy for the treatment of a haematological condition,
for example, idiopathic thrombocytopenic purpura, may present for
advice concerning peri-splenectomy
care. This patient may also pre-
sent with a sheet from the surgeon
requesting the administration of the
preoperative vaccines.
Those with longstanding coeliac
disease (and not known to be hyposplenic or asplenic) may present
following the second episode of pneumococcal sepsis. Such patients may
have questions concerning the possible reasons for the recurrent sepsis.
Sometimes a well patient may
present with a scar under their left
costal margin dating from many
years ago, while being uncertain of
the surgery that was performed. If
there are symptoms requiring further investigation, the GP should
perform tests to determine the presence or absence of the spleen or
splenic function.
Diagnosis
Confirmation
A HISTORY of splenectomy and/
or the presence of a relevant surgical scar most often confirms the
diagnosis. In the scenario where
the surgical history is uncertain
or where (non-surgical) medical
causes of asplenia are being considered, investigations are needed
to confirm the absence of the
spleen or splenic function.
The usual and most useful investigations to confirm the diagnosis
of absent or diminished spleen
function are:
• Full blood examination with
blood film to document the presence of Howell–Jolly bodies.
• IgM memory B cells are a potential parameter for assessing
splenic function; however, more
studies are necessary for its validation.
In most situations, the above
blood tests would answer the question. If there is ongoing doubt,
radiological imaging might be considered, for example ultrasound or
CT scan.
24
| Australian Doctor | 13 September 2013
Figure 2:
Howell–Jolly
bodies on a
blood film
(arrows).
Howell–Jolly bodies
The most common investigation
for the confirmation of an asplenic
or hyposplenic state is a full blood
examination with a blood film
asking for the presence of Howell–
Jolly bodies.
Howell–Jolly
bodies
are
intraerythrocytic inclusions that
remain in the circulation due to
the loss of the filtering function of
splenic tissue (figure 2). Degenerate red cells that have Howell–Jolly
bodies are usually filtered from the
blood by the spleen. Their presence are therefore an indication
of a poorly functioning or absent
spleen, although they do not necessarily reflect spleen function.
Other blood film changes such
as macrocytosis and thrombocytosis are variable and much less specific for the diagnosis of asplenia
or hyposplenism.
Other investigations
Poor or absent spleen function
may also be confirmed by the
demonstration of decreased levels
Functional hyposplenism
Functional hyposplenism should
be considered or suspected in
patients with medical conditions
known to be potentially associated with hyposplenism, following
presentation with severe pneumococcal sepsis, or if there is bloodfilm evidence of a hyposplenic
state (eg, the presence of Howell–
Jolly bodies).
Screening of family members
of blood IgM memory B cells. This
can be performed by the pathology departments in the large
teaching hospitals with reference
ranges as established by the referwww.australiandoctor.com.au
ence laboratory.2 The results are
interpreted by the immunologists.
The absence of spleen tissue can be
confirmed by imaging techniques
as above.
Congenital asplenia is uncommon, but when an individual presents with this in general practice,
advice should be given to screen
family members. This would
involve drawing up a family tree,
highlighting family members
who have experienced a relevant
medical conditions such as pneumococcal sepsis. A full blood
examination should be offered to
family members and possibly an
IgM memory B cell test. A referral to an infectious diseases physician with these results would be
advisable.
Overwhelming post-splenectomy infection
PATIENTS without a spleen or
with functional hyposplenism are
at increased risk of fulminant sepsis, manifested by the rapid onset
of septicaemia, sometimes with
meningitis. There is often no obvious primary source of infection and
there may only be a very short or
non-specific prodrome. Following
this, the patient rapidly progresses
to shock, often requiring admission to intensive care for inotropic
and ventilatory support. Highlevel bacteraemia is common, with
the organism sometimes visible on
a routine blood film.
The mortality from overwhelming
post-splenectomy infection is over
50% with death typically occurring
within 24-48 hours. Early diagnosis
and timely initiation of antibiotic
therapy is usually life-saving.
For survivors, the physical, psychological and financial cost of
this infection is often considerable.
Amputation of limbs, loss of hearing and the need for prolonged
rehabilitation affects not only the
patient but often has significant
impact on family and home life.
Causative organisms
The most common cause of overwhelming post-splenectomy infection is Streptococcus pneumoniae,
responsible for over 70% of cases,
Figure 3: Coil
embolisation
of the main
splenic artery.
varies between reports. The condition has been estimated to occur
in one in 500 patients per year.
An early Australian study documented an incidence of 0.42 cases
per 100 person years.3 The incidence appears to be greater in children than adults, with incidence
of 4.4% of children and 0.9% of
adults in another report.4
The risk may be greater in the
first 2-3 years after splenectomy.
However, the risk of severe overwhelming
post-splenectomy
infection is lifelong. This was demonstrated in a British report of 77
cases of such infection, in which
most cases occurred between 10
and 30 years after splenectomy.5
Prevention
followed by Neisseria meningitidis
and Haemophilus influenzae type
b. Capnocytophaga canimorsus,
a member of the normal flora of
many animals, is also a cause of
this infection and is most often
acquired through cat, dog and
other animal bites or scratches. A
recently described Gram-negative
bacillus, Bordetella holmesii, has
been reported as a further cause of
sepsis in asplenic individuals. Salmonella has also been reported as
a significant pathogen in children
with sickle cell and hyposplenism.
Risk
The risk of overwhelming postsplenectomy infection in a person
with asplenia or hyposplenism
Guidelines
There have been a number of published guidelines outlining strategies for the prevention of sepsis in
asplenic and hyposplenic patients.
British guidelines were published
in 1996 by the British Committee for Standards in Haematology
Clinical Haematology Taskforce
and updated in 2002. In Australia,
consensus recommendations were
prepared by a working group of
the Australasian Society for Infectious Diseases with representatives
from most Australian states and
published in 2008.6 More recently,
updated recommendations concerning vaccinations in asplenic
patients have been included in
the 10th edition of the Australian
Immunisation Handbook.7
Procedural and surgical
intervention
There have also been increased
efforts at splenic tissue preservation by splenic artery embolisation, partial splenectomy, or
splenorrhaphy. The embedding
of splenic tissue in the omentum
has also been suggested. In recent
years there have been more successful attempts to salvage spleen
tissue in the trauma setting by targeted embolisation of the splenic
segment that is bleeding (figure 3).
In our experience, most patients
retain adequate splenic function
after splenic artery embolisation
and hyposplenia rarely follows
this intervention.
Accessory spleen
An accessory spleen has been
described in up to 10% of postmortems and, while uncommon,
it is possible for some spleen function to return some time after splenectomy due to the presence and
subsequent enlargement of such an
accessory spleen or splenunculus.
Management
THE three pillars of sepsis prevention in asplenic or hyposplenic
patients are education of individual
patients and their families, specific
and booster vaccinations, and the
use of daily preventive and emergency antibiotics.
Education
Education is the most critical component of prevention of sepsis in this
setting. The importance of education has been highlighted by one
study that demonstrated patients
with the best knowledge concerning
the risk of asplenia had the lowest
incidence of sepsis.
In many studies, a significant
proportion of patients with past
splenectomy have been found to be
unaware that they were at increased
risk of severe sepsis. Patients were
either not educated concerning the
risk or had forgotten what they had
previously been told.
General aspects of the education
of an asplenic patient or hyposplenic
patient include the following:
• There should be an education session at the time of splenectomy.
This is ideally done on the day of
discharge from hospital. It may
take up to 30 minutes in order to
allow the patient to ask questions
and to demonstrate an understanding of risk. This may need to
be repeated annually.
• Ideally, a family member or
friend should attend the education session. They should also be
informed of the increased lifelong
risk of bacterial infections and the
recommended preventive strategies.
• The most important point of the
session should be to stress how the
symptoms and signs of a bacterial
Figure 4: Medical alert
card for asplenic or
hyposplenic patients.
infection may be detected (eg, high
temperatures, vomiting, nausea,
severe headaches). An early medical review is essential and the
emergency supply of antibiotics
should be started immediately —
this may be life-saving.
• Patients should be reassured that
minor viral infections, such as
the common cold, without fever
or systemic symptoms, are not
causes for concern. However, the
patient should be reminded that
the annual influenza vaccine may
protect them against influenza
and that there is the possibility of
Figure 5: Vaccination card for asplenic or hyposplenic patients.
doses (figure 5). It is important
secondary bacterial infection as a
that this card be updated when
complication of influenza.
vaccines are given. Vaccines that
•Written information about risk
have been given in the past or at
and an outline of preventive stratthe time of hospital admission
egies including the necessary vacshould be recorded in order to
cination regime should be given.
reduce duplication.
This should include translated
•P
atients should be educated conmaterial for non-English speaking
cerning the potential risk of anipopulations.
mal bites and scratches.
• The patient should be advised to
• S urgical and dental procedures
carry, at all times, a medical alert
generally do not require antibiotic
in the form of a laminated card or
cover over and above what is usumedallion (figure 4).
ally given or indicated.
• The patient should be given a
•H
ospital and general practice medcompleted vaccination card that
includes timing of future booster
cont’d next page
13 September 2013 | Australian Doctor |
25
from previous page
ical records should be highlighted
so that it is clear the patient has
asplenia or hyposplenism.
• Vaccinations should be discussed
with pregnant or breastfeeding
mothers.
• A patient who travels frequently
should be advised to be vigilant
with limb exercises while flying
because there is some evidence
that splenectomy may be a risk
factor for thromboembolic disease.
Good communication between
hospitals, specialist physicians and
surgeons, and the patient’s GP is
needed. The GP plays an important role in the ongoing care of the
patient by regular reinforcement of
the educational messages, ensuring
vaccinations are up-to-date and that
the patient has a supply of preventive and/or emergency antibiotics.
A regular opportunity for ensuring
patients have a relevant knowledge
base is at the time of the annual
influenza vaccination.
In Victoria, patients can register
on the Victorian Spleen Registry,
run by the Victorian Spleen Service. This service supplies registered
patients with an educational kit that
includes laminated medical alert
cards and an individualised report
with vaccine booster dates. The
Victorian Spleen Service also has an
educational DVD available that can
be given to patients and their families (see Online resources).
Immunisation
The patient should be up-to-date
with the recommended routine
immunisations. It is safe to give liveattenuated vaccines to patients with
asplenia or hyposplenism if there
is no concomitant contraindication to live vaccines. Vaccination of
pregnant and breastfeeding women
should be discussed, although the
underlying risk for overwhelming
post-splenectomy infection is not
increased in these groups.
The immunisation regimen recommended by the Victorian Spleen
Service based on the 10th edition
of the Australian Immunisation
Handbook is presented in figures
6 and 7.7 These recommendations
are likely to change further with the
introduction of new vaccines in the
future and updates may be found on
the Victorian Spleen Service website
(see Online resources).
A significant problem for some
patients is that these vaccines are
not funded by the National Immunisation Program, and provision
may need to be made through local
hospitals to supply vaccines.
The timing of vaccination is
important. In those patients undergoing elective vaccination, the optimal timing is at least 7-14 days
before splenectomy. For those
patients who have undergone
emergency splenectomy (eg, as a
result of trauma), the optimal timing
for vaccination is 7-14 days following the surgery. Occasionally when
patients are discharged within the
immediate seven-day postoperative period and thought unlikely to
return for review, vaccination at the
time of discharge may be necessary.
It is safe to give all vaccines at the
same time; they should be administered at different sites.
In the setting of chemotherapy,
radiotherapy or immunosuppres-
26
Figure 6:
Recommended
vaccinations
pathway for
immunisationnaive individuals
with asplenia or
hyposplenism.
Victorian Spleen Service (VSS) incorporating the Victorian Spleen Registry
Recommendations for the prevention of infection in ASPLENIC/HYPOSPLENIC patients
applicable for patients over 18 years of age – (JULY 2013)
(If the patient has previously received vaccinations, see separate VSS recommendations)
***Give 1st dose 7 – 14 days prior to splenectomy (elective) or at least 7 days after splenectomy (emergency) and
verbal consent should be obtained prior to administration of vaccines ***
Disease prevented
Primary Course
Conjugate
Pneumococcus
0.5mL IM
Conjugate ACWY
Meningococcus
(Pneumovax 23)
0.5mL IM or SC
Conjugate ACWY
>8 weeks
(Menveo, Menactra)
0.5mL IM
Haemophilus
influenzae type b
Polysaccharide
8 weeks later
(Prevenar 13)
(Menveo, Menactra)
0.5mL IM
Hib
Vaccine Brand name
Synflorix
Prevenar 7 or 13
Pneumovax 23
Menveo or Menactra
Menjugate or NeisVac-C or Meningitec
Mencevax or Menomune
If a patient has a bleeding disorder and there is a concern
about giving vaccinations (i) delay administration until
corrected (ii) contact Victorian Spleen Registry or a
Haematology Registrar
5 years later
(Pneumovax 23)
0.5mL IM or SC
Conjugate ACWY *
(Menveo, Menactra)
0.5mL IM
Annually -prior to
influenza season
Every year
Influenza
For more information on
# and * please refer to page 2 of this document
Polysaccharide #
5 years later
No boosters
(Liquid PedvaxHIB, Hiberix) 0.5mL IM
Influenza
Revaccinations
Vaccine Abbreviations
Type of vaccine
10 valent pneumococcal conjugate vaccine
7 or 13 valent pneumococcal conjugate vaccine
23 valent pneumococcal polysaccharide vaccine
(Conjugate ACWY) Quadrivalent meningococcal conjugate vaccine
Meningococcal C conjugate vaccine
(Polysaccharide ACWY) Quadrivalent meningococcal polysaccharide vaccine
Abbreviation
10vPCV
7vPCV or 13vPCV
23vPPV
4vMenCV
MenCCV
4vMenPV
Victorian Spleen Service (VSS) Recommendations for the prevention of infection in asplenic (splenectomy) or hyposplenic patients over 18 years of age (V30 July 2013). Derived from Immunisation Handbook 10
1 of 2 pages
Edition, 2013. VSS is based at The Alfred hospital, Melbourne. Website: spleen.org.au or email [email protected] T: (03) 9076 3828 F: (03) 9076 2431
th
Victorian Spleen Service (VSS) incorporating the Victorian Spleen Registry
Recommendations for the prevention of infection in patients
who have PREVIOUSLY RECEIVED ASPLENIC/HYPOSPLENIC VACCINES
and are over 18 years of age. (JULY 2013)
***Give 1st dose 7 – 14 days prior to splenectomy (elective) or at least 7 days after splenectomy (emergency)
and verbal consent should be obtained prior to administration of vaccines ***
Revaccinations Disease
prevented
Follow
up vaccines
received
Give
1st dose
7 – 14 days prior toVaccines
splenectomy
(elective)inorpast
at least 7 days after splenectomy
(emergency)
and verbal consent should be obtained prior
to administration.
Pneumococcus
Polysaccharide
> 1 year
Conjugate (7 or 10 valent)
> 8 weeks
(Pneumovax 23)
(Prevenar 7, Synflorix)
Conjugate
Polysaccharide
Conjugate
(Prevenar 13)
0.5mL IM
Polysaccharide#
(Pneumovax 23)
0.5mL IM or SC
Next Pneumovax 23 to be given
5 years after previous one
(Prevenar 13) 0.5mL IM
8 weeks
(Pneumovax 23)
0.5mL IM or SC
Figure 7:
Recommended
vaccinations
pathway for
individuals
with asplenia/
hyposplenism who
have received prior
immunisations.
5 years
No prior vaccine: give Prevenar 13 then 8 weeks later Pneumovax
23
Conjugate ACWY
(Menveo/Menactra)
No prior vaccine
8 weeks
Conjugate ACWY
(Menveo/Menactra)
Meningococcus
Conjugate C
(NeisVac-C, Menjugate, Meningitec)
Polysaccharide ACWY
> 3 years
(Mencevax, Menomune)
Conjugate ACWY
(Menveo, Menactra)
Haemophilus
influenzae type b
>8 weeks
Conjugate ACWY
(Menveo, Menactra) 0.5mL IM
5 years
Conjugate ACWY
(Menveo/Menactra) 0.5mL IM
5 years
Conjugate ACWY*
(Menveo, Menactra)
0.5mL IM
If received < 8 weeks ago, give 2nd dose of Menveo/Menactra at 8 weeks. If > 8 weeks ago next dose at 5 years
Hib (Liquid PedvaxHIB, Hiberix)
Only one vaccine required
Influenza
Annually prior to influenza season
Influenza
5 years
# and * please see refer to page 2
Victorian Spleen Service (VSS) Recommendations for the prevention of infection in previously vaccinated asplenic (splenectomy) or hyposplenic patients over 18 years of age (V1 July 2013). Derived from
th
Immunisation Handbook 10 Edition, 2013. VSS is based at The Alfred hospital, Melbourne. Website: spleen.org.au or email [email protected] T: (03) 9076 3828 F: (03) 9076 2431 1 of 2 pages
sive therapy, immunisation should
ideally be given no later than two
weeks before such therapy begins or
delayed until at least three months
after completion of chemotherapy
or radiotherapy. Children with
malignancies may be given vaccines
during medical treatments.
Pneumococcal vaccination
Pneumococcal vaccination is of
critical importance in the prevention of overwhelming post-splenectomy infection as this is the most
common causative organism. In
adults, the 23-valent pneumococcal
polysaccharide vaccine (23vPPV)
has mostly been used. However,
updated recommendations now
include the recently available
13-valent pneumococcal conjugate
vaccine (13vPCV). This is because
the conjugate vaccines have proven
long-term immunogenicity (including production of immune memory)
over and above that provided by the
polysaccharide vaccine.
The current recommendation,
based on the Australian Immunisation Handbook, is that recently
splenectomised patients receive the
conjugate vaccine (13vPCV), followed eight weeks later by the polysaccharide vaccine (23vPPV) and
with the 23vPPV dosing repeated at
five years.7
Patients who have received an initial 23vPPV need to wait 12 months
before receiving the conjugate vaccine (13vPCV). These patients then
receive a second revaccination
with the 23vPPV five years later.
Currently it is recommended that
patients should only receive three
pneumococcal polysaccharide vaccines in a lifetime.
Meningococcal vaccination
For meningococcal vaccination,
quadrivalent conjugate vaccines
(4vMenCV) have recently become
available and are replacing the polysaccharide quadrivalent vaccines
(4vMenPV) and the monovalent C
conjugate vaccine (MenCCV).
Asplenic patients should have the
quadrivalent meningococcal conjugate vaccine (4vMenCV), followed
by a second dose at eight weeks
and repeated every five years. For
those patients who have already
received the polysaccharide vaccine (4vMenPV) or the serogroup C
conjugate vaccine, then the timing
of the subsequent 4vMenCV is outlined in figure 7.
Other vaccinations
One dose only of Haemophilus
influenzae type b vaccine is rec-
ommended. Most importantly,
annual influenza immunisation
is required. This is important for
preventing secondary bacterial,
including pneumococcal, infection,
subsequent to influenza.
Antibiotics
We recommend daily preventive
antibiotics for all patients for a
minimum of two years following
splenectomy when the risk of sepsis is considered to be at its highest.
‘Otherwise well’ patients, such as
a young person who had splenectomy because of trauma, might be
able to stop daily antibiotics after
this time, but it needs to be reinforced that the risk of serious infection is lifelong for all asplenic or
hyposplenic patients. For patients
who are immunocompromised long
cont’d page 28
from page 26
term or taking immunosuppressive
medications daily, preventive antibiotics should be continued for the
duration of the reduced immunity.
This may be lifelong.
Patients with asplenia should be
educated about the need for daily
preventive antibiotic therapy to
decrease the risk of overwhelming
post-splenectomy infection. This
decreases but does not completely
rule out the possibility of such infection.
If a patient without any history
of an underlying medical condition
has had a splenectomy many years
ago and has not been on antibiotics
during that time, then we would not
usually restart daily antibiotics but
would ensure immunisation is upto-date.
Choice of antibiotic
The first-line choice of preventive
antibiotics is either oral amoxycillin 250mg or 500mg once daily, or
phenoxymethylpenicillin (penicillin
V) 250mg or 500mg twice daily.
Patients over 80kg require the larger
daily dose. Dosing for children aged
up to two age is 20mg/kg of amoxycillin daily or phenoxymethylpenicillin 125mg orally every 12 hours.
For those with penicillin allergy,
either roxithromycin 150mg daily
(for children 4mg/kg up to 150mg
daily) or erythromycin 250mg once
daily is recommended.10 Overall,
there has been an increased concern
about antibiotic resistance. Despite
this, we believe that the benefit of
antibiotics in this patient group outweighs this concern.
Although this infection has not been
described in Australia, travellers
to at-risk areas including parts of
North America (eg, the New England region) should be warned of
the risk.
Clues to the diagnosis of babesiosis
include travel to endemic regions,
history of tick bite and a febrile
illness. If suspected, referral to an
infectious diseases physician is
essential.
Pregnancy
Meningitis
The risk of meningococcal meningitis
is higher in some parts of the world,
such as sub-Saharan Africa. For
travel to such regions it is especially
important that meningococcal vaccination is up-to-date.
Animal contact
Emergency supply
All patients should have an emergency or standby supply of antibiotics
regardless of whether they are taking daily antimicrobial prophylaxis.
We recommend that patients not
allergic to penicillin have amoxycillin 3g (6 × 500mg) taken altogether
when indicated.
In the presence of penicillin
allergy, we recommend either rox-
ithromycin 300mg daily or erythromycin 1g qid.
The emergency antibiotic supply should be taken when the person develops symptoms of possible
serious bacterial infection such as
high fevers, shivers, vomiting and/
or diarrhoea. They are encouraged
to begin this emergency supply of
antibiotics especially in cases when
medical care is not immediately
available. They should then present
to their GP or the hospital ED as
early as possible.
Special considerations
Travel
Malaria
PEOPLE with asplenia or hyposplenism are at increased risk of malaria
when travelling to malaria-endemic
regions. The risk of malaria in those
without spleen function is increased
2-3-fold, with high levels of parasitaemia compared with other travellers.6
The presentation of malaria for
people with asplenia/hyposplenism
is often more severe (with high fever
and sometimes hypotension) when
compared with people with normal splenic function. They should
therefore seek expert travel medicine advice if planning to travel to
malaria-endemic parts of the world.
Preventive measures include pretravel advice dependent on itinerary
and estimated risk. Antimalarial
medications, the use of barrier precautions such as long sleeves and the
use of insect repellents are encouraged. If the risk of malaria is very
high, then it may be recommended
that the person not travel to that
country. If symptoms of malaria
occur during travel, there should
be an agreed action plan such as
accessing medical review as quickly
as possible and/or taking an agreed
emergency antimalarial treatment
course.
Babesiosis
Babesiosis, another intraerythrocytic protozoal infection, is transmitted by tick bites and can also
cause severe infections in people
with asplenia or hyposplenism.
Pregnancy and breastfeeding can
present some challenges in this
patient group and therefore need
special consideration. There are limited data on the safety of administering the newer vaccines to pregnant
women and specialist advice should
be sought. Generally, the influenza
vaccine is safe and recommended
in women who are pregnant during
the influenza season.
Significantly, there is an increased
risk of overwhelming post-splenectomy infection caused by an organism (Capnocytophagia canimorsis)
that is a member of the normal oral
flora of animals, especially cats and
dogs.
Case studies
Case study 1
A 30-YEAR-old woman became
unwell initially with a mild sore
throat and headache. The following day she woke with high fever,
abdominal pain, diarrhoea and
vomiting. She presented to her GP
who immediately sent her to the
hospital ED.
She had a past history of Hodgkin lymphoma as a teenager, and
management included a staging
splenectomy and chemotherapy.
She had had one dose of pneumococcal vaccine and took prophylactic penicillin for the five years
after her splenectomy. She had
been quite well before this presentation.
On admission to hospital she
was very unwell with a fever of
39.5ºC, was hypotensive, and
began bleeding from needle puncture sites. Shortly after presentation to the hospital her condition
rapidly deteriorated and she was
transferred to the ICU, where she
received inotropic and ventilatory
support.
Coagulation tests revealed disseminated intravascular coagulation. A full blood examination
revealed a neutrophilia with left
shift and toxic changes. The blood
film revealed multiple cocci and
diplococci both extra- and intracellularly, reflecting overwhelming
post-splenectomy infection (figure
8).
Blood cultures isolated a
penicillin-susceptible
Neisseria
meningitidis serogroup W135.
Unfortunately, despite intensive
care she continued to deteriorate
and died the day after hospital
admission. This infection may
28
Bites or significant scratches from
animals should be cleaned with
disinfectant, and should have early
medical review and antimicrobial
therapy, such as amoxycillin–clavulanic acid, if there is any concern
about local or systemic infection.
Alerts
Medical records of patients with
asplenia or hyposplenism should
be highlighted.
Ideally when haematologists
report the presence of Howell–
Jolly Bodies on a blood film, or
when splenic tissue is processed by
anatomical pathologists, a comment on the risk of overwhelming
post-splenectomy infection should
be included in the report.
References
Figure 8:
Blood film of
patient with
overwhelming
post-splenectomy
infection showing
multiple cocci and
diplococci both
intracellularly and
extracellularly.
Figure 9:
Disseminated
intravascular
coagulation
secondary to
sepsis in the foot.
have been prevented if she had
received a meningococcal vaccination or was on prophylactic penicillin, or if she had an emergency
supply of antibiotics and had been
educated to use them at the onset
of her illness.
Case study 2
A 63-year-old man presented to hospital with a two-day history of high
fevers, lethargy and confusion. On
arrival he was hypotensive with a
blood pressure of 80/50mmHg, with
a temperature of 39ºC. There were
necrotic areas of skin on both his
feet and hands. His right foot below
the level of the ankle joint appeared
necrotic (figure 9). Initial investigations demonstrated acute renal failure with lactic acidosis and evidence
of disseminated intravascular coagulation.
He underwent emergency intubation, required inotropic and
fluid support and was admitted to
the ICU. He was started on broadspectrum antibiotics and renal
replacement therapy.
He had a past history of coronary artery disease and a longterm diagnosis of severe ulcerative
colitis. Before this presentation he
had not been acutely unwell and
was working full time.
Blood cultures taken on admission subsequently grew Streptococcus pneumoniae. Cocci were
also seen on a normal blood film
(figure 10, next page), indicating
a very high level of bacteraemia.
There was no history of previous
pneumococcal vaccination.
He initially received daily hyperbaric therapy, which resulted in
some improvement in the necrotic
skin areas. However, during
the progress of his treatment he
required a right below-knee amputation. He spent 65 days in hospital with several complications
including an MI. He was then discharged to a rehabilitation centre.
cont’d page 30
1. Jones P. Victorian Spleen Registry
update. Warrnambool Infectious
Diseases Seminar, Warrnambool
Hospital, Warrnambool, Victoria,
21 September 2012.
2. Cameron P, et al. Splenectomy
associated changes in IgM
memory B cells in an adult spleen
registry cohort. PLoS ONE 2011;
6(8):e23164.
3. Cullingford GL, et al. Severe late
postsplenectomy infection. British
Journal of Surgery 1991; 78:716-21.
4. Holdsworth R, et al.
Postsplenectomy sepsis and its
mortality rate: actual versus
perceived risks. British Journal of
Surgery 1991; 78:1031-38.
5. Waghorn DJ. Overwhelming
infection in asplenic patients:
current best practice preventive
measures are not being followed.
Journal of Clinical Pathology 2001;
54:214-18.
6. Spelman D, et al. Guidelines for
the prevention of sepsis in asplenic
and hyposplenic patients. Internal
Medicine Journal 2008; 38:349-56.
7. NHMRC. The Australian
Immunisation Handbook 10th
Edition. Australian Government,
Canberra, 2013.
8. El-Alfy MS, et al. Overwhelming
postsplenectomy infection: is quality
of patient knowledge enough for
prevention? Haematology Journal
2004; 5:77-80.
9. Jones P, et al. Letter to the editor.
Australian and New Zealand
Journal of Surgery 2009; 79:854-61.
10. A
ntibiotic Expert Group.
Therapeutic Guidelines:
Antibiotic,Version 14, Therapeutic
Guidelines Limited, Melbourne,
2010.
from page 28
He remained in the rehabilitation
centre for a further 45 days.
This patient had no history of
past splenectomy but had inflammatory bowel disease, which is a
condition that can be associated
with hyposplenism. Investigations
during his hospitalisation did
reveal a low level of IgM memory
B cells and the presence of Howell–Jolly bodies. His hyposplenic
state had not previously been identified.
Following this diagnosis, he
Figure 10:
Streptococcus
pneumoniae Gram
stain on blood
film.
has received the full set of recommended vaccinations and remains
on lifelong preventive daily
amoxycillin. He was fortunate to
survive such overwhelming postsplenectomy infection but at great
costs to himself, family and the
health system. If his hyposplenic
state had been identified before
his acute presentation, and if the
appropriate pneumococcal vaccination had been given together
with daily amoxycillin, it is likely
that this severe episode of sepsis
would have been prevented.
infection. The Victorian Spleen
Service aims not only to educate
the asplenic or hyposplenic person, but also to continually update
medical providers who do not frequently encounter these patients in
the general practice setting. Physicians outside Victoria are showing
interest in joining forces to have
their patients included on the Victorian Spleen Registry. Currently,
the updated recommendations are
available on the VSS website (see
Online resources) and this can be a
useful resource for people residing
outside Victoria.
Strategies to prevent overwhelming post-splenectomy infection
are, at present, a rapidly evolving
field and further developments are
likely, including the availability of
new conjugate pneumococcal and
meningococcal vaccines. The establishment of a spleen registry is an
important step in increasing awareness and education of patients and
doctors to tackle the persistently
high rates of sepsis and mortality.
Online resources
Victorian Spleen Registry/Service
Detailed information for patients
and GPs, and management of
register of patients
www.spleen.org.au
Conclusion
THE absence of a spleen or a
poorly functioning one is a significant health condition that requires
ongoing medical review and education about preventive strategies.
Severe overwhelming post-splenectomy infection is reduced through
patient education, vaccinations,
and preventive and emergency antibiotics where indicated.
Unfortunately, despite the formulation and promulgation of
strategies for the prevention of
sepsis in asplenic patients, and the
availability of very active vaccines
and effective antibiotics, cases of
overwhelming
post-splenectomy
infection continue to occur. Many
studies demonstrate suboptimal
compliance with the recommendations for prevention. A spleen
service that houses a registry, such
as that now established in Victoria, had been proposed as the
most likely mechanism to improve
adherence with preventive strategies and thereby prevent cases of
overwhelming
post-splenectomy
Instructions
How to Treat Quiz
Complete this quiz online and fill in the GP evaluation form to earn 2 CPD or PDP points.
We no longer accept quizzes by post or fax.
The mark required to obtain points is 80%. Please note that some questions have more than one correct answer.
Asplenia and hyposplenism
— 13 September 2013
1. W
hich TWO statements are correct
regarding epidemiology and causes of
asplenia and hyposplenism?
a) 4
0% of allogeneic bone marrow transplant
recipients have functional hyposplenism
b) Sickle cell anaemia is not known to lead to
hyposplenism
c) T
he most common cause of asplenia is cancer
d) HIV infection may predispose to hyposplenism
2. W
regarding the presentation of asplenia and
hyposplenism?
a) P
neumococcal sepsis may be the presenting
complaint of a hitherto undiagnosed functional
hyposplenism
b) A patient with rheumatoid arthritis and the
presence of Howell–Jolly bodies in blood film
may not have hyposplenism
c) M
eningitis and fulminant sepsis may be a
presenting sign of a patient with asplenia or
hyposplenism
d) Children with asplenia or hyposplenism do not
present with overwhelming post-splenectomy
infection
3. W
regarding the investigation and diagnosis of
a) A
history of splenectomy and/or the presence
of a relevant surgical scar most often confirms
the diagnosis
b) The first-line investigation is a full blood
examination with a blood film to search for
Howell–Jolly bodies
c) H
owell–Jolly bodies are fragments of red cells
GO ONLINE TO COMPLETE THE QUIZ
www.australiandoctor.com.au/education/how-to-treat
sheared off by stenosed splenic arteries
d) Hyposplenism may be confirmed by
measuring the serum level of T cells
4. Which TWO statements are correct
regarding overwhelming post-splenectomy
infection?
a) Overwhelming post-splenectomy infection has
a mortality rate of over 50%
b) The risk of severe overwhelming postsplenectomy infection is lifelong and is not
reduced by any previous septic episode
c) Death from overwhelming post-splenectomy
infection usually occurs within six hours of
onset
d) Most cases of overwhelming postsplenectomy infection occur within 3-5 years
of splenectomy
regarding the organisms that cause
overwhelming post-splenectomy infection?
a) Capnocytophagia canimorsus that causes
overwhelming post-splenectomy infection
from an animal cannot be carried by a well
household pet
b) Salmonella is a significant pathogen in children
with sickle cell disease and hyposplenism
c) The most common cause of overwhelming
post-splenectomy infection is Haemophilus
influenzae type b
d) Bordetella holmesii may cause Gram-negative
overwhelming post-splenectomy sepsis
regarding the prevention of overwhelming
post-splenectomy infection?
a) Patients on daily preventive antibiotics
are protected against the development of
overwhelming post-splenectomy infection
b) Daily preventive antibiotics should be given
for a maximum of six months only following
splenectomy
c) Early diagnosis of sepsis has no impact
on the prognosis of overwhelming postsplenectomy infection
d) All patients should have an emergency supply
of antibiotics regardless of whether or not
they are taking daily antimicrobial prophylaxis
regarding the education of patients on
preventing complications associated with
a) Long-distance travellers either by car or plane
should be advised regarding management of
the increased risk of thromboembolic disease
b) Patients should seek medical attention
immediately with any sign of an incipient
URTI
c) Patients should carry a medical alert in the
form of a laminated card or medallion at all
times
d) Dental procedures should be covered with
flucloxacillin
regarding immunisations in patients with
a) People who are heterozygous for the sickle
cell trait may have a reduced response
to vaccinations that use polysaccharide
antigens
b) Immunisation should be given 7-14 days
before splenectomy
c) Live attenuated vaccines are contraindicated
in patients with asplenia or hyposplenism
d) Influenza immunisation does not help
protect against morbidity and mortality from
pneumococcus
regarding the antibiotics used in patients
with asplenia and hyposplenism?
a) The first-line choice of antibiotics is a
penicillin
b) The alternative choice of antibiotic is
cephalexin
c) Patients over 80kg require a higher dose for
daily prevention
d) Patients should monitor the effect of
emergency antibiotics for two days before
seeking attention in the hospital ED
regarding travel and contact with
animals for patients with asplenia and
hyposplenism?
a) Meningococcal vaccination should be given
when travel is planned for sub-Saharan Africa
b) Patients with an animal bite are at greater
risk of infections than patients with a normal
functioning spleen
c) The risk of malaria to people with asplenia is
the same as for the general population
d) The rabies vaccination protects against
babesiosis transmitted by animal bites
CPD QUIZ UPDATE
The RACGP requires that a brief GP evaluation form be completed with every quiz to obtain category 2 CPD or PDP points for the 2011-13 triennium.
You can complete this online along with the quiz at www.australiandoctor.com.au. Because this is a requirement, we are no longer able to accept
the quiz by post or fax. However, we have included the quiz questions here for those who like to prepare the answers before completing the quiz online.
how to treat Editor: Dr Steve Liang
Email: [email protected]
Next week Corneal disease can be a manifestation of pathology of the cornea itself, or the ocular surface — including the lids and lacrimal system, and even systemic disease. The next How to Treat
looks at the management of common corneal conditions, including the current surgical management of pterygium, keratoconus and corneal decompensation. The author is Dr Raymond SK Loh, cornea
consultant, department of ophthalmology, Flinders Medical Centre, Bedford Park, and Eyemedics, Adelaide, SA.
30

Introduction - Australian Doctor

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