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Treatment injury case study
August 2013 – Issue 58
Bobbing oscillopsia
Adverse drug reaction
EVENT: Vestibular damage &
bobbing oscillopsia
INJURY: Case Study
Jim, a 47-year-old farmer, was admitted to hospital with a history of fever, chills, rigors and weight loss.
Jim had a history of melanosis coli, diagnosed at a
screening colonoscopy three years prior, and was being
treated for gastro-oesophageal reflux disease. An
admission screening for sepsis was negative and Jim was
reviewed by the surgical team, who ordered a CT scan of
the abdomen. The CT scan showed a bowel perforation,
which the team treated conservatively with triple
antibiotic therapy (including gentamicin), intravenous
fluids, close observation and keeping Jim nil by mouth.
The gentamicin levels were monitored and remained
within therapeutic levels, although one trough
level was slightly high. Jim showed significant
improvement and was discharged from hospital
Key points
• Gentamicin has a particular predisposition to damage
the balance part of the inner ear, although it can cause
cochleotoxicity (hearing loss and tinnitus). The effects
are permanent and irreversible
• Aminoglycoside ototoxicity is typically noticed during
the recovery period following severe illness
• Ototoxicity can occur even when considerable care has
been taken with administration and monitoring
• Risk factors include:
−− continuous or interrupted treatment for more than
seven days, therefore treatment should not exceed
seven days unless it is imperative
−− renal impairment
−− high fever
−− serious illness
−− concomitant use of other ototoxic agents such as
platinum antineoplastics
• The use of alternative medications and obtaining advice
from an infectious diseases specialist should be considered
• Patients should be advised of the treatment risks and
signs to report.
10 days later with a further two-week course of
Augmentin and a booking for a colonoscopy.
Following discharge Jim found that he was having
trouble with his vision and balance when he was out
on the farm. Jim described the world as “bobbing
up and down” and said he felt as though he was
permanently unsteady. He found that he felt sick
when he bent down, and when he turned his head
quickly there was a lag before his eyes caught up. Jim
was having difficulty working on the farm as he felt
unsafe driving around the property on his own and was
struggling to perform his duties.
Jim was referred to an ear, nose and throat (ENT)
specialist, who found that there were catch-up ocular
saccades after rapid rotatory (short arc) movements,
and that Romberg’s test showed Jim to be clearly
unsteady when sharpened. The ENT specialist did
note that Jim’s hearing was essentially normal with
a minimal high tone loss. In the opinion of the ENT
surgeon the 10 days of gentamicin treatment had been
sufficient to ablate most if not all of his peripheral
vestibular apparatus. Jim was referred for a follow-up
bithermal caloric ENG (electronystagmography) and
balance exercises were provided.
Following Jim’s check-up with his general practitioner
(GP), a claim was lodged for treatment injury on the
basis that Jim’s bobbing oscillopsia was a characteristic
feature of gentamicin ototoxicity. ACC accepted cover
for vestibulotoxicity and was able to support Jim with
his wages compensation and ongoing assessments.
Expert commentary
Peter Blake, Otolaryngologist/Head and neck
surgeon, MA (Oxon), MB, BS (Lond), FRACS
• Bobbing oscillopsia is a characteristic feature of
aminoglycoside ototoxicity. Gentamicin has a
particular predisposition to damage the balance part
Case study
of the inner ear, although it can cause cochleotoxicity
(hearing loss and tinnitus). The effects are permanent
and irreversible.
• Jim was treated for 10 days, and the risk of
developing ototoxicity significantly rises if treatment
is continued for longer than seven days. Ototoxicity
may be noticed during the period of treatment, but
more typically is noticed during the recovery period
following severe illness. The medications are slow
to enter the inner ear, and also slow to diffuse out,
so toxic side-effects are often not evident until after
treatment has ceased. Ototoxicity can occur even
when very considerable care has been taken with
administration, and peak and trough levels are
assiduously monitored throughout treatment.
• There is a known genetic predisposition to
aminoglycoside ototoxicity.
• Aminoglycoside antibiotics have been used for
decades, and are cheap to buy but expensive to use.
Alternatives are available. The advice of an infectious
diseases specialist in difficult cases may be helpful.
• Risk factors for the development of
aminoglycoside ototoxicity include continuous or
interrupted treatment for more than seven days
(the longer the period of treatment, the greater
the risk), renal impairment, high fever, serious
illness, concomitant use of other ototoxic agents,
e.g. platinum antineoplastics, and possibly preexisting hearing loss. Medications such as loop
diuretics (frusemide, ethacrynic acid), vancomycin
and clindamycin, and possibly the cephalosporins,
potentiate the ototoxic effect of aminoglycosides.
• Where possible, patients should be advised of the risk
of potential damage. Advice should include immediate
reporting of difficulty reading print (a feature of
How ACC can help your patients following treatment injury
Many patients may not require assistance following their treatment injury.
However, for those who need help and have an accepted ACC claim, a
range of assistance is available, depending on the specific nature of the
injury and the person’s circumstances. Help may include things like:
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contributions towards treatment costs
weekly compensation for lost income (if there’s an inability to
work because of the injury)
help at home, with things like housekeeping and childcare.
No help can be given until a claim is accepted, so it’s important to
lodge a claim for a treatment injury as soon as possible after the
incident, with relevant clinical information attached. This will ensure
ACC is able to investigate, make a decision and, if covered, help your
patient with their recovery.
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oscillopsia), noticed hearing loss or the onset of
tinnitus. Treatment should be ceased immediately.
Management
• Standard dosing regimes are now once daily and
usually undertaken with the assistance of the
hospital pharmacist.
• Slow, intravenous infusion (30-60 minutes) of
the medication diluted to 50-100ml is the safest
method of administration. Rapid infusion of a
single dose should be avoided.
• Peak and trough levels should be carefully
monitored and kept within therapeutic limits. If it
is necessary to continue treatment for longer than
a few days, it is important to continue to monitor
serum drug levels, and not assume that it is safe
to continue the dosage regime because the peak
and trough levels were initially satisfactory.
• Aminoglycosides impair renal function, and this
results in a tendency for the serum levels to rise after
a few days, unless dosage is appropriately adjusted.
• Treatment should not exceed seven days unless it
is imperative.
References
1. Inherited susceptibility to aminoglycoside ototoxicity: Genetic heterogeneity and the
clinical implications. Rosaria AMS et al. American Journal of Otolaryngology – Head and
Neck Medicine and Surgery (May 1999) 20:3, 151-156.
2. Inappropriate prescribing of aminoglycosides: Risk factors and impact of an antibiotic
control team. Zahar JR et al. Journal of Antimicrobial Chemotherapy (2006) 58: 651-656.
2. Risk factors for the development of auditory toxicity in patients receiving
aminoglycosides. Moore RD et al. Journal of Infectious Diseases (1984) 149 (1): 23-30.
3. Aminoglycoside ototoxicity in the human. Fee WE. The Laryngoscope (October 1980)
90, supplement S24, 1-19.
4. Risk factors for toxicity in elderly patients given aminoglycosides once daily. Paterson
DL et al. Journal of General Internal Medicine (1998) 13 (11): 735-739.
5. Incidence of and Significant significant risk factors for aminoglycoside associated
nephrotoxicity in patients dosed by using individualised pharmacokinetic monitoring.
Bertino JS et al. Journal of Infectious Diseases (1993) 167 (1): 173-179.
Claims information
Between July 2005 and February 2012 ACC decided 79 claims relating to the use of
gentamicin, with 45 being accepted. The most commonly accepted injuries were
deafness/hearing loss, vestibular damage and toxicity. Bobbing oscillopsia was present
in four of the accepted claims.
The median client age group was 60-64 and men accounted for 55% of the accepted claims.
The most common reasons for declining claims were that no link could be established
between treatment and the claimed injury and that the injury had not been caused by
treatment.
About this case study
This case study is based on information amalgamated from a number
of claims. The name given to the patient is therefore not a real one.
The case studies are produced by ACC’s Treatment
Injury Centre, to provide health professionals with:
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an overview of the factors leading to treatment injury
expert commentary on how similar injuries might be avoided in
the future.
The case studies are not intended as a guide to treatment injury cover.
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