Olympus camedia c 730 ultra zoom manual

CORRESPONDENCE
4
Singh S, Wig N, Chaudhary D, Sood NK,
Sharma BK. Changing pattern of acute
poisoning in adults: experience of a large
North-West Indian hospital. J Assoc Phys
India 1997; 45: 194–97.
3
4
Herpes encephalitis
Sir—The magnetic resonance (MR)
Clinical picture, published in the
Oct 26 issue (p 1286),1 showed
predominantly right temporal lobe
involvement with herpes encephalitis in
a patient with altered mental status and
fever. However, the scan shown was
not a T2-weighted image with
gadolinium, as stated by the authors,
but a fluid-attenuated inversionrecovery
(FLAIR)
image
with
gadolinium (also referred to as
contrast-enhanced FLAIR image).
On FLAIR images, as seen in this
case, the signal from cerebrospinal
fluid is suppressed and becomes dark,
by contrast with a very bright
appearance on T2-weighted images.
FLAIR MR sequences have become
essential in assessment of brain lesions,
because of their high sensitivity, which
generally
surpasses
T2-weighted
images, especially in areas adjacent to
cerebrospinal fluid-containing spaces.2
The high signal seen in the apex of the
fourth ventricle in the presented case is
a flow-related artifact, typically seen on
FLAIR images.
Furthermore, T2-weighted sequences
are generally not used with gadolinium,
since they do not provide contrast
enhancement; perfusion MRI uses
specially designed dynamic postcontrast T2-weighted sequences, on
which, by contrast, a loss of signal is
seen with accumulation of gadolinium.3
For a time, contrast-enhanced
FLAIR images were increasingly
popular, and early reports suggested
they could even replace contrastenhanced
T1-weighted
images.
However, results of a recent study4
showed that FLAIR images with
gadolinium have lower sensitivity and
specificity than standard contrastenhanced
T1-weighted
images.
Evidence
is
accumulating
that
diffusion-weighted images, known for
their reliability in acute stroke assessment, seem to be more sensitive than
FLAIR images for detection of herpes
encephalitis.5
Zoran Rumboldt
Department of Radiology, University Hospital
“Sisters of Mercy”, Vinogradska 29, Zagreb,
HR 10000, Croatia
(e-mail: [email protected])
1
2
Martin K, Franco-Paredes C. Herpes
encephalitis. Lancet 2002; 360: 1286
Okuda T, Korogi Y, Shigematsu Y, et al.
Brain lesions: when should fluid-attenuated
260
5
inversion-recovery sequences be used in
brain evaluation? Radiology 1999; 212:
793–98.
Lev M, Rosen B. Clinical applications of
intracranial perfusion MR imaging.
Neuroimaging Clin N Am 1999; 9: 309–31.
Singh SK, Leeds NE, Ginsberg LE. MR
imaging of leptomeningeal metastases:
comparison of three sequences.
AmJ Neuroradiol 2002; 23: 817–21.
Teixeira J, Zimmerman RA, Haselgrove JC,
Bilaniuk LT, Hunter JV. Diffusion imaging
in pediatric central nervous system
infections. Neuroradiology 2001; 43:
1031–39.
event”, or that “an individual’s
sociological milieu is responsible for
his or her cancer”.
Ultimately, Shuter’s criticisms of
Thabet and colleagues do not
convince, because he chooses to
undermine sound scientific evidence
to further his own agenda.
Martin Sidis
Adan Hospital, Ministry of Health, Kuwait
(e-mail: [email protected])
1
2
Emotional problems of
Palestinian children living
in a war zone
Sir—Jonathan Shuter (Oct 5, p 1098)1
commits a serious error in his use of
junk science (faulty scientific analysis
to further a special agenda). He
criticises Abdel Aziz Mousa Thabet
and colleagues2 for inferring causality
from a cross-sectional analysis in their
study of Palestinian children living in
war zones. He also disputes the
investigators’ findings that children’s
emotional responses to exposure to
political violence are acute and severe.
Shuter argues that this finding is not
justified because it is similar to “the
conclusion that low-calorie drinks
cause obesity, since many obese
people drink these beverages”.
Shuter’s objections prompt me to ask,
are we making the same sort of
mistake in cross-sectional studies of
smoking and lung cancer, when we
say that smoking causes lung cancer,
because many patients with lung
cancer are smokers?
Next,
Shuter
suggests
that
Palestinian
children’s
emotional
problems are caused by “the
educational, political, religious, and
social environment in which are
raised”. To use the same analogy, if I
said that “the educational, political,
religious, and social environment in
which human beings are raised causes
emotional problems and this leads to
lung cancer, but not the smoking”
would The Lancet publish my letter?
Shuter goes on to reject Thabet and
colleagues’ comparison of children
exposed to home bombardment and
demolition with a control group.
Shuter maintains that such demolition
“is not a random event” since many of
the homes that were destroyed “were
bomb factories or munitions depots”.
Again, Shuter’s contention is exactly
as absurd as saying that “those
exposed to smoking who developed
lung cancer were already harbouring
cancer, and this was not a random
Shuter J. Emotional problems in
Palestinian children living in a war zone.
Lancet 2002; 360: 1098.
Thabet AAM, Abed Y, Vostanis P.
Emotional problems in Palestinian
children living in a war zone: a crosssectional study. Lancet 2002; 359:
1801–04.
Ocular tuberculosis
Sir—Volker Grosse and colleagues
(Sept 21, p 922)1 describe a 30-year-old
Gambian man who presented with a
constellation of symptoms and signs
that suggested a differential diagnosis of
systemic tuberculosis in addition to
metastatic carcinoma and lymphoma.
Obtaining ocular tissue for definitive
diagnostic purpose is associated with a
significant ocular morbidity. Therefore,
a high degree of clinical suspicion is the
key to early diagnosis. Instead of
enucleating a vital sense organ like the
eye, I feel that the authors should
have done a biopsy of an easily
accessible site such as the cervical lymph
node to demonstrate the characteristic
findings of caseating granuloma and
Mycobacterium tuberculosis.
The effectiveness of antituberculosis
treatment has obviated the need for
operative intervention in tuberculomas
and tuberculous abscesses, except when
decompression is required to prevent
permanent
neurological
deficits.
Furthermore, unlike other bacterial
abscesses, tuberculous abscesses do not
necessarily require drainage.2 When
patients with tuberculosis elsewhere in
the body develop clinical features of
ocular involvement, the treatment of
ocular tuberculosis is along the same
lines as treatment of pulmonary
tuberculosis.3 Therefore, instead of a
hurried enucleation, the patient
described by Grosse and colleagues
could have been given a chance to
preserve the right eye pending followup assessment after antituberculosis
treatment.
Another important point is that
retobulbar optic neuritis and the
resultant amblyopia are the most
frequent and serious adverse effects of
ethambutol treatment.4 Symptoms
include
blurred
vision,
central
THE LANCET • Vol 361 • January 18, 2003 • www.thelancet.com
For personal use. Only reproduce with permission from The Lancet Publishing Group.
CORRESPONDENCE
scotomas,
and
red-green
colour
blindness. The visual symptoms precede
a measurable loss of visual acuity. This
complication is dose-related and occurs
in less than 1% of patients given a daily
dose of 15 mg/kg, and increases with a
daily dose of 25 mg/kg.3 Ocular toxicity
induced by antituberculosis treatment
should have been an important
consideration when starting drugs.
Grosse
and
colleagues,
having
enucleated one eye, could have chosen a
more appropriate drug than ethambutol,
given its known ocular toxicity. Thus,
the aim should have been to preserve the
remaining healthy eye from an
iatrogenic insult leading to irreversible
loss of vision.
Lastly, Grosse and colleagues
mention that they excluded other causes
of
generalised
lymphadenopathy,
including toxoplasmosis, brucellosis,
yersiniosis, and syphilis by serological
tests. Such elaborate and costly
serological investigations might not be
possible and economically viable in a
developing country like India, which
bears 28·4% of the entire world’s
burden of tuberculosis, and where every
second an individual older than 20 years
is infected with M tuberculosis.5 A simple
biopsy of an easily accessible cervical
lymph node would have been more
appropriate.
Abraham Kuruvilla
Department of Neurology, Sree Chitra Tirunal
Institute for Medical Sciences and Technology,
Trivandrum 695 011, India
(e-mail: [email protected])
1
2
3
4
5
Grosse V, Bange FC, Tischendorf J,
Schmidt RE, Manns MP. A mass in the eye.
Lancet 2002; 360: 922.
Haas DW, Des Prez RM. Mycobacterium
tuberculosis. In: Mandell GL, Bennett JE,
Dolan R, eds. Principles and practices of
infectious diseases, 4th edn. New York:
Churchill Livingston, 1995: 2213–43.
Garg SP, Venkatesh P. Ocular tuberculosis.
In: Sharma SK, Mohan A, eds. Tuberculosis.
New Delhi: Jaypee Brothers, 2001: 294–303.
Vanscoy RE, Willowske CJ. Antituberculous
agents. Mayo Clinic Proc 1992; 67: 179–87.
Sharma SK. Introduction. In: Sharma SK,
Mohan A, eds. Tuberculosis. New Delhi:
Jaypee Brothers, 2001: 1–4.
Histopathological results showed an
eyeball full of necrotic tissue extending
to the iris and ciliary body.
Kuruvilla also argues that ethambutol
is associated with optic neuritis and
therefore should be used with caution in
a patient who has lost already one eye.
We were aware of this possible ocular
toxicity, but thought it to be a problem
only with higher doses.1 However, we
acknowledge that there have been
reports of serious visual impairment on
conventional doses, with permanent
blindness in some cases, and painfully
slow recovery in others.2 Our treatment
was
guided
by
the
current
recommendation that, unless the rate of
resistance to isoniazid is less than 4%,
the initial antituberculosis treatment
regimen should consist of isoniazid,
rifampicin,
pyrazinamide,
and
ethambutol or streptomycin.3 Optic
neuritis due to ethambutol usually
resolves after the drug is stopped.4 In
this case, the patient was monitored
closely for the development of
symptoms and signs related to ocular
toxicity. He developed no optic neuritis.
We agree that, in a country like India,
with relatively low income levels and
high
incidence
of
tuberculosis
(184 cases per 100 000 people),5
serological investigations to exclude
other
causes
of
generalised
lymphadenopathy
might
not
be
economically sound. In Germany,
however, the incidence of tuberculosis is
low (11 per 100 000). Therefore, while
the diagnosis of tuberculosis was
pending, other possible causes for
generalised lymphadenopathy were
excluded, which included serological
tests for syphilis, toxoplasmosis, and
brucellosis.
*V Grosse, F C Bange, J Tischendorf,
R E Schmidt, M P Manns
Divisions of *Clinical Immunology (VG, RES),
and Gastroenterology and Hepatology (JT, MPM),
Department of Medicine, and Department of
Microbiology (FCB), Hannover Medical School,
30625 Hannover, Germany
(e-mail: [email protected])
1
Authors’ reply
2
Sir—Abraham Kuruvilla is right that
avoidance of ocular biopsy or
enucleation is preferable if possible.
Early diagnosis and treatment is
essential for saving the sight of patients
with
ocular
manifestations
of
tuberculosis. Yet in this case, the patient
presented when infection was already
far advanced and the eye could not be
saved. Enucleation was done because of
acute panophthalmitis and complete
destruction of the overlying retina, and
not exclusively for diagnostic reasons.
3
4
5
American Thoracic Society. Treatment of
tuberculosis and tuberculosis infection in
adults and children. Am J Respir Crit Care
Med 1994; 149: 1359–74.
Russo PA, Chaglasian MA. Toxic optic
neuropathy associated with ethambutol:
implications for current therapy.
J Am Optom Assoc 1994; 65: 332–38.
Small PM, Fujiwara PI. Management of
tuberculosis in the United States.
N Engl J Med 2001; 345: 189–200.
Friedberg DN, Lorenzo-Latkany M. Ocular
complications of tuberculosis. In: Rom WN,
Garay SM, eds. Tuberculosis. Boston: Little,
Brown and Company, 1996: 557–66.
World Health Organization. Global
tuberculosis control: surveillance, planning,
financing. WHO Report 2002. Geneva:
WHO, 2002. http://www.who.int/gtb/
publications/globrep02/index.html (accessed
Jan 8, 2003).
THE LANCET • Vol 361 • January 18, 2003 • www.thelancet.com
Avoidance of bioflavonoid
supplements during
pregnancy
Sir—On July 28, 2002, the Italian
Health Ministry published a statement
in the Gazzetta Ufficiale, ordering that
all dietary supplements containing
bioflavonoids should be labelled: “Not
to be taken during pregnancy”. This
precautionary decision was taken
because of the possibility of an
increased risk of severe diseases during
the first year of life due to prenatal
exposure to bioflavonoids.
The scientific basis for this
association was provided by reports that
suggested a relation between dietary
flavonoids and infant leukaemia.1,2
However, the discussion sections of
these reports highlighted a large
number of questions (epidemiological,
molecular, and medical) that should be
addressed and that make the relation
between bioflavonoids and infant
leukaemia very weak. Moreover, there is
evidence that dietary bioflavonoids
afford protection from cancer owing to
their antioxidant properties.3–5
Supplements
containing
bioflavonoids and marketed in Italy
provide a median of 50–60 mg/day
(range 2–500) bioflavonoids. The
average daily quantity of bioflavonoids
in a Mediterranean diet is more than
2000 mg. Thus, although the
supplements
are
probably
not
necessary, their average bioflavonoid
content corresponds to 3–5% of the
dietary intake in Italian pregnant
women.
Although the evidence provided by
the above cited reports suggests that
precautions could be taken, there are
no scientific grounds for such a
decision, nor for unduly alarming the
public. In fact, the decision to label the
supplements is now having a striking
effect, and women who were taking
supplements or who took them in
pregnancy are becoming anxious about
the possible effects of these tablets on
their children. Furthermore, supplements contain other ingredients, such
as folic acid, proteins, and minerals,
which could be beneficial for pregnant
women.
To add to the confusion, no
adequate information has been issued
to physicians and health operators to
allow risk-benefit analysis and risk
communication. No other countries, to
our knowledge, have forbidden these
compounds in pregnancy.
We believe that decisions concerning
public health should not be taken
without a proper strategy for risk
assessment and risk communication,
261
For personal use. Only reproduce with permission from The Lancet Publishing Group.
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