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Annals of African Medicine
Annals of African Medicine Society
ISSN: 1596-3519
Vol. 3, Num. 1, 2004, pp. 42-44
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Annals of African Medicine, Vol. 3, No. 1, 2004, pp.
42-44
PRIMARY HYPERPARATHYROIDISM PRESENTING WITH MULTIPLE
PATHOLOGICAL FRACTURES AND NORMOCALCAEMIA
I. A. Mungadi, *A. O. Amole and **U. H. Pindiga
Departments of Surgery, *Radiology and **Pathology, Usmanu Danfodiyo University Teaching
Hospital, Sokoto, Nigeria
Reprint requests to: Dr.
I. A. Mungadi, Department of Surgery, Usmanu Danfodiyo University Teaching
Hospital, Sokoto, Nigeria. E-mail imungadi@yahoo.com
Code Number: am04012
ABSTRACT
The diagnosis of primary hyperparathyroidism (PHPT) is a rarity
in developing countries. We report a 30-year old Nigerian farmer seen at the
Usmanu Danfodiyo University Teaching Hospital, Sokoto with multiple pathological
fractures. The diagnosis of PHPT was made based on these bone changes and
the elevated parathyroid hormone level. The patient however had normocalcaemia. Computerised
tomography localised a
left inferior parathyroid adenoma. He had uneventful parathyroidectomy but developed
hungry bone syndrome that was successfully treated with active vitamin D and
oral calcium. The differences in presentation between patients from developed
countries as well as the apparent rarity of PHPT in tropical
countries are stressed.
Key words: Hyperparathyroidism, parathyroid adenoma,
normocalcaemia, pathological fracture
INTRODUCTION
Primary Hyperparathyroidism (PHPT) is an unstimulated
and inappropriately high secretion of parathyroid hormone for the concentration
of plasma ionised
calcium. 1
Primary hyperparathyroidism is
estimated to be prevalent in approximately 1% of adult population and the usual
causes are parathyroid adenoma, hyperplasia and,
rarely, parathyroid carcinoma. 2 The diagnosis of PHPT is a rarity
in developing countries 3 probably because of the difficulty of
making a diagnosis in an environment where there are limited facilities for
serum calcium
estimation, parathyroid hormone assay and parathyroid gland
imaging. The diagnosis can be very perplexing especially because the expected
hypercalcaemia associated with PHPT may be masked by calcium, protein or vitamin
D deficiency. 4 - 6 this is a report a case of PHPT presenting with
multiple fractures secondary to parathyroid adenoma but who had
normocalcaemia. It is the only documented case of PHPT from the North-Western
Nigeria with such an unusual presentation.
CASE REPORT
A thirty year old peasant Nigerian farmer presented
on the 11th of February 1999 with painful swellings of the right
hip, knee and ankle of eighteen months
duration. The ankle pain and swelling followed a sprain while working on his
farm. Two weeks later, the painful swellings of the hip and knee developed on
falling down while climbing a staircase due to his ailing ankle. He had no
other symptoms and no positive family history of similar illness.
On examination, he was chronically
ill looking and pale. His weight could not be taken with the available standing
scale due to multiple lower limb fractures. He had tender swellings around
the right hip, knee and ankle joints. The knee swelling was particularly gross,
irregular and warm, with a combination of firm
and bony hard areas. All the joint movements around the affected knee were
limited. The distal femoral shaft was fractured. Plain radiographs of the pelvis
and right knee revealed centrally located intramedullary, expansile radiolucent
lesions in the subtrochanteric and supracondylar regions of the femur with pathological
fractures respectively (Figures 1 and 2).
The serum calcium level was 2.4
mmol-1 (normal: 2.2 - 2.6 mmol-1), with phosphate level
of 1.6 mmol-1 (normal: 0.8 - 1.5 mmol-1) and alkaline
phosphatase level of 134 IU/l). The serum albumin was 34g/l and serum calcium
corrected for observed albumin was 2.52 mmol/l (corrected calcium in mmol/l
= observed calcium in mmol/l + (40 - albumin in g/dl) x 0.02). 1 The
parathyroid hormone level was elevated to 132 pmol/l (normal <105
pmol/l). The packed cell volume was 21%; the total leukocyte count was 3.0 x
109/l with an ESR of 150 mm/hour (Westergreen). Serum urea, electrolyte
and creatinine were within normal limits. There was no radiological evidence
of nephrolithiasis. A contrast enhanced computed
tomographic (CT)scan showed a 1.8 x 1.9 cm non-enhancing discrete
lesion in the inferior pole of the left thyroid lobe, consistent with a left
inferior parathyroid adenoma (Figure 3). Urinary calcium and acid base status
were not assessed.
The patient had a successful
neck exploration and parathyroidectomy. The tumour weighed about 18g and showed
parathyroid adenoma on histology. He developed hungry bone syndrome with serum
calcium level dropping to 1.7 mmol-1 on the fourth post-operative
day. The serum calcium normalised on active
vitamin D and oral calcium. The patient was being considered for osteosynthesis
by the orthopaedic surgeon when he requested for a discharge against medical
advice probably for traditional bone setting. He had since been lost to follow-
up.
DISCUSSION
Primary hyperparathyroidism (PHPT) is a disease
commonly due to solitary parathyroid
adenoma. 2 It was considered rare in developing countries but recent
experience has shown that its apparent rarity may be due to paucity of reports
from these countries and also to limited diagnostic facilities. 3, 7 Our
case has shown that with adequate facilities, more reports of the disease may
soon be emanating from developing countries.
Primary hyperparathyroidism (PHPT)
has protean manifestations. The advent of automated serum biochemical analysis
has highly augmented its diagnosis and has made asymptomatic hypercalcaemia
its commonest presentation in the developed
countries. 8 This is in contrast to our experience, as in many developing
countries, where patients usually present with metabolic bone disease and multiple
fractures.
The incidence of metabolic bone
disease in patients with PHPT in developing
countries is very high. 6, 9 The reasons advanced for this is the
high prevalence of protein, vitamin D and dietary calcium deficiencies and the
high dietary phytate and phosphates in some cultures. The protein deficiency
can further reduce total serum calcium since 50% is bound to albumin. These
patients therefore, tend to be normocalcaemic even after the correction of
hypoabluminaemia. Our patient is a typical example and similar findings have
been noted in previous reports. 5, 6 It is therefore pertinent for
clinicians practicing in the developing countries to note that nutritional deficiencies
can be seen in their patients, unlike those from the developed nations, making
hypercalcaemia irrelevant in the diagnosis of PHPT. Hence, serum calcium level
may not be part of the criteria for surgical intervention contrary to what was
earlier suggested. 10 Multiple fractures, although uncommon, have
been described as some of the indicators for
pathological fractures in PHPT. 3 They suggest a late presentation
of the disease and the severity of the disease. With an increased awareness
and knowledge of the presentation of PHPT in developing
countries and the availability of diagnostic facilities, late spresentation
could be avoided. However, since patients with fractures in Northern Nigerian
commonly opt for traditional bone setting as evidenced by our patient, many
cases of PHPT may still present late to the orthodox doctors practicing in
this area. Furthermore, patients with multiple fractures secondary to a parathyroid
adenoma in our environment may find it difficult to appreciate the role of
parathyroidectomy in the management of multiple fractures located, for instance,
in the lower limbs. They may
therefore opt for traditional bonesetters. This unusual situation therefore
makes aggressive health education of the populace a necessary priority.
Parathyroidectomy is the treatment
of choice in PHPT. Success of the surgery is determined largely by early
diagnosis and localisation of the adenoma before surgery. 11,
12 Despite the late presentation of our case, the diagnosis was assisted
by radiographic studies including CT and the assay of the parathyroid hormone. These
pre-operative investigations made decisions for early surgery possible.
Sudden post-operative hypocalcaemia
may be a major complication of parathyroidectomy
as shown by our patient. The incidence of this hungry bone syndrome is likely
to be high in our environment due to the associated pre-operative dietary calcium
and vitamin D deficiency. Therefore, this potential complication should be anticipated
and aggressive nutritional support to address these deficiencies must be instituted
appropriately.
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