Keywords:
Basal ganglia calcification, Graves’ disease, Hyperthyroidism, thyroid
disease.
Abstract :
Basal ganglia calcifications have been linked to a wide range of causes.
Mostly it is an idiopathic finding, especially in elderly.
Endocrinological and neurological disorders are major causatives.
Hyperthyroidism was not related to this finding. We present a case of
incidental basal ganglia calcification in man with Grave’s disease.
Introduction :
Basal ganglia calcifications (BGCs) have been linked to a variety of
endocrinological and neurological conditions, it is also a frequent
incidental finding in imaging studies with again (1). Bilateral BGCs
might also reflect calcium metabolism disorders, intoxication, and
autoimmune and genetic diseases (2). It can be categorized into primary
and secondary brain calcifications. Among secondary calcifications,
parathyroid disorders are the most common. Infections are another reason
for intracerebral calcifications (1).
Graves’ disease, an autoimmune thyroid gland disorder is considered the
most common cause of hyperthyroidism and thyrotoxicosis, it includes
goiter, exophthalmos, and pretibial myxedema if fully expressed. (3)
The occurrence of Graves’ disease with bilateral BGCs has never been
reported in the literature. Here we present a case of a young patient
who presented with lower limb weakness and thyrotoxicosis to be
diagnosed later as Graves’ disease with thyrotoxic periodic paralysis
and a CT scan showing bilateral BGCs. Our case suggests a pathological
correlation.
Case presentation :
A 27-year-old Filipino man with no known chronic illnesses presented to
the Emergency Department (ED) complaining of acute bilateral leg
weakness that started 2 hours prior to coming to ED. He also had some
weakness in his arms but was less in severity. The patient denied any
pain or numbness. He mentioned a history of weight loss of 5kg during
the past month.
Vital signs were normal apart from tachycardia 117/minute. Physical
examination revealed muscle power 4/5 in both upper limbs, 3/5 in both
lower limbs, and diffuse goiter. ECG demonstrated sinus tachycardia.
Given the acute onset of the weakness, head computed tomography was done
to rule out stroke, however, it showed Bilateral basal ganglia and
dentate nuclei calcifications Figure (1). Blood tests were remarkable
for high FT4 >100 mIU/L (11.0- 23.3), low TSH<
0.01 mIU/L (0.30-4.20), low potassium level =3 mmol/L (3.5-5.3), and
high TSH receptor antibodies (TRAP).
The patient was diagnosed with Thyrotoxic periodic paralysis with
Graves’ disease. He improved dramatically after intravenous potassium
replacement. He has been started on Carbimazole 20 mg twice per day and
propranolol 40 mg twice per day.
Further workup showed normal levels of calcium, phosphorus, and basal
metabolic panel. The patient had no remarkable central nervous system
infections in the past, no exposure to lead or other heavy metals, and
his family history was irrelevant. All in all, the suspicion of a
potential association between Graves’ disease and basal ganglia
calcification was raised.
Discussion :
Basal ganglia calcification has been reported in 15-20% of the
population, mainly in patients over 65 years. (4) This radiological
finding is also known as Fahr’s disease, a rare inherited or sporadic
neurological disorder, with an age of onset around the fourth to the
fifth decade presented with a movement disorder or/and neuropsychiatric
manifestations. However, differential diagnosis is wide in the case of
basal ganglia calcifications which include primary and secondary
categories. (5) Primary or idiopathic refers to the presence of
radiological findings in the absence of clinical symptoms or metabolic
and electrolyte panel disturbances (6). Secondary basal ganglia
calcification has been reported in relation to endocrinological and
neurological disorders. Parathyroid abnormalities were the most common
underlying pathology due to abnormality in calcium/phosphor balance
which leads to generalized calcification and basal ganglia were reported
as one of the possible locations. In 1980 an article published by Chad
R. Cohen et al categorized secondary causes into four main categories;
endocrine causes that include hypoparathyroidism,
pseudohypoparathyroidism, pseudo-pseudohypoparathyroidism, Congenital/
Developmental, inflammatory, and toxic, they concluded that any
calcification in the basal ganglia, dentate nucleus, multiple areas in
the cortex in a patient of any age should be considered as pathological,
while calcification in globus pallidus is considered pathological in
patients under 40 years, it is physiological findings in patients more
than 40 years (7). MG Harrington et al included hypothyroidism among the
possible reasons for this radiological finding (8). Another article
reported bilateral striocerebellar calcification associated with
Hashimoto’s disease, although the mechanism is not clear, the deposits
included mucopolysaccharide colloid material which might raise suspicion
for a relation between both entities (9). In our case, the patient came
with muscle weakness with low potassium levels and laboratory tests
revealed the presence of thyrotoxicosis with later positive TSH receptor
antibodies (TRAB) which confirmed the diagnosis of Graves’ disease. No
abnormalities in calcium, phosphorus, or parathyroid hormone (PTH) were
found. We could not find any reports suggesting a correlation between
basal ganglia calcification and hyperthyroidism in general and Graves’
disease in specific. We report the first case that suggests this
correlation. The early age of our patient and absence of any family
history of a neuropsychiatric disorder or similar findings, the absence
of any infections, travel history, or toxic exposure support the
correlation in our patient.
Conclusion :
Although many disorders were related to intracranial calcifications.
Basal Ganglia calcifications are most associated with endocrinological
causes. Parathyroid disorders were a well-reported entity in the context
of this radiological finding however thyroid disorder especially
hyperthyroidism was not reported before. We suggest that Graves’ disease
might be associated with bilateral basal ganglia calcification.