Multiple stress fractures and
periorbital hypopigmentation in a young and active adult – a
potentially subtle clinical findings of Vitamin D Deficiency
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SUMMARY
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A 21 year old white Caucasian male of Lithuanian origin presented
with chronic left foot pain. He presented to the GP and was eventually
referred for a specialist orthopaedic opinion. An MRI of his left foot
revealed multiple stress fractures and areas of microtrabecular injury.
This raised high suspicion for an underlying metabolic bone disorder and
the patient was referred to the Rheumatology team for further
investigations. Blood tests revealed a severe Vitamin D deficiency
(25nmol/L) and the patient was investigated for further organic causes.
An interesting clinical finding was that of bilateral periorbital
hypopigmentation. There is currently little evidence confirming causal
relationships between Vitamin D deficiency and cutaneous
hypopigmentation. This case prompts further research into this
relationship as the earlier detection vitamin D deficiency based on
clinical findings could potentiate prompt interventions and therefore
minimise the unfavourable effects of an easily treatable clinical
condition. |
BACKGROUND
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Foot pain is a common presentation in general practice. Whilst a
large proportion of presentations result from muskuloskeletal conditions
such as plantar fasciitis, some rarer causes of foot pain are a result
of bone related disorders such as an accesory navicular, accessory
cuboid-os peroneum, bone stress at the base of the fifth metatarsal,
bone stress at the base of the second metatarsal and navicular bone
stress 1. Subtle ankle fractures can also present
similarly to a sprain and require imaging for further assessment,
usually with plain films followed by MRI scans2. As
the foot is subject to repetitive mechanical forces, it is prone to
overuse injuries such as stress fractures, which may be an indication of
an underlying pathological process in an otherwise fit and well
individual 3.
Stress fractures occur as a result of cyclical injury to bone
caused by repeated mechanical stress 4. Whilst the
majority of stress fractures occur in the young and healthy population,
particularly in young athletes, there is evidence to suggest that
underlying metabolic abnormalities may be responsible for stress
fractures in particular cohorts of patients. In particular, patients
with reduced bone mineral density due to low dietary intake of calcium
or low levels of active vitamin D have a higher risk of developing
stress fractures. In women, menstrual disturbances as well as low body
index have been identified as risk factors 5.
As foot pain is generally a common presentation, adequate
detection of treatable underlying pathological processes is essential
for optimum management. Early detection reduces the risk of
complications such as intractable pain or non-union, the latter of which
requires surgical correction. Whilst literature is present on the link
between osteomalacia and stress fractures, little is published on
periorbital hypopigmentation and its link with low levels of vitamin D.
There is however plentiful literature present on the treatment of
hypopigmentation in the form of vitiligo with vitamin D analogues and
steroids. This case report highlights a potentially rare presenting
feature of a common clinical condition and proposes further research
into cutaneous hypopigmentation and its association with vitamin D
deficiency and osteomalacia-induced stress fractures.
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CASE
PRESENTATION
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A 21 year old white Caucasian male of Lithuanian origin presented
with chronic left foot pain after working 8-hour long shifts in a casino
during the winter months. He reported pain during his work that involves
long hours of walking and standing. The patient presented to the GP with
generalised foot pain, worse at the base of the 5th metatarsal and at
the heel which had gradually been worsening over time. He reported no
significant trauma however complained that the pain was worse on
activity and alleviated at rest. There were no complaints of inability
to weight bear.
The patient was initially referred to the musculoskeletal services
for physiotherapy. After achieving little benefit from this, he was
referred for a specialist orthopaedic opinion. On initial consultation
with the orthopaedic team, he complained of generalised foot pain worse
on activity pain and swelling was noted in the region of the 4th
metatarsal, which was at risk of increased loading due to a relatively
prominent 4th metatarsal head. X-Ray of the left foot revealed a stress
fracture through the mid-shaft of the 3rd metatarsal and the patient
underwent magnetic resonance imaging (MRI) for further assessment which
revealed multiple stress fractures and areas of microtrabecular injury.
During his follow up appointment with the orthopaedic team weeks
later, there was no tenderness or bruising around the dorsal aspect of
the foot or the medial sesamoid. The patient had a full range of
movement of the ankle and subtalar joint. The patient reported that
following a change in his job, the symptoms had improved dramatically
and subsided completely without the need for any intervention.
An interesting finding on general examination was the patient’s
extensive bilateral periorbital hypopigmentation (See figure 1). This
coupled with his geographic background, occupational risk factors and
confirmation of multiple stress fractures on MRI raised a high suspicion
for underlying bone metabolism pathology such as osteomalacia and the
patient was investigated further for organic causes of pathological
fractures.
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INVESTIGATIONS
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Initially the patients foot pain was investigated with plain film
imaging. An X-Ray of the left foot revealed a stress fracture through
the mid-shaft of the 3rd metatarsal with callus formation and bony
erosion in the medial head of the 1st metatarsal (see figure 2). These
findings were also evident clinically with tender points on examination.
For further visualisation, an MRI of his left foot was performed which
revealed multiple stress fractures, particularly affecting the third and
fourth metatarsal bones with microtrabecular injury at the navicular,
cuboid and the base of the fifth metatarsal (see figres 3,4 and 5).
Periostal thickeing and fascial oedema were seen along most of the
fourth metatarsal as well as at the distal aspect of the third
metatarsal which were findings suggestive of stress fractures. These
results raised high suspicion for an underlying metabolic bone disorders
such as osteomalacia. The patient was investigated further with blood
tests, which confirmed a severe Vitamin D deficiency (25nmol/L). The
patient was treated with Vitamin D supplements and referred to the
Rheumatology team for further investigation of other organic causes. |
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TREATMENT
From an orthopaedic point of view, the patient was advised to wear
a walker boot and to be non weight bearing. He was also advised to
remove the walker boot to exercise his ankle in order to maintain range
of movement and prevent a deep vein thrombosis and subsequent pulmonary
embolisms. Based on local protocol, as the patient was able remove the
walker boot to exercise his ankle, he did not require chemical
thromboprophylaxis. In the follow up consultation, the patient reported
not using the walker boot due to inconvenience however reported that
only weeks after changing to a less physically demanding job, his
symptoms had completely resolved. Regarding the osteomalacia, the
patient was advised to commence oral Vitamin D supplementation and
referred to the Rheumatology team for screening of underlying metabolic
abnormalities. The patient’s periorbital hypopigmentation remained
unchanged.
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