Differentials
Common
Primary hyperparathyroidism
History
usually asymptomatic but may have a history of renal stones, long bone pain, constipation, fatigue, abnormal psyche, slow thought, depression
Exam
long bone tenderness, ectopic corneal calcification, palpable neck mass (rare)
1st investigation
- serum calcium:
elevated
- parathyroid hormone:
elevated or inappropriately normal despite high calcium
More - 24-hour urine calcium:
elevated
Other investigations
- bone densitometry:
T-score <-2.5
Malignancy
Multiple myeloma
History
weight loss, bone or back pain, family history of myeloma, infections, renal failure, history of monoclonal gammopathy of unknown significance
Exam
non-specific findings
1st investigation
- serum calcium:
elevated
- parathyroid hormone:
low
- serum protein electrophoresis:
monoclonal gammopathy
Uncommon
Familial hypocalciuric hypercalcaemia
Vitamin D intoxication
History
history of vitamin supplementation
Exam
non-specific findings
1st investigation
- serum calcium:
elevated
- parathyroid hormone:
normal or suppressed
Other investigations
- plasma vitamin D (1,25 OH colecalciferol):
elevated
Lithium
History
history of lithium use
Exam
non-specific findings
1st investigation
- serum calcium:
slightly elevated
More
Other investigations
Thiazide diuretics
History
history of thiazide diuretic use
Exam
non-specific findings
1st investigation
- serum calcium:
slightly elevated
More
Other investigations
Chronic renal failure and secondary hyperparathyroidism
History
chronic renal failure and dialysis with bone pain
Exam
bone tenderness
1st investigation
Other investigations
- urinalysis:
haematuria and/or proteinuria
- kidney ultrasound:
small kidney size; presence of obstruction/hydronephrosis; kidney stones
Hyperthyroidism
History
anxiety, weight loss, normal or increased appetite, sleep disturbance, palpitations, heat intolerance, sweating, eye pain, bone pain
Exam
diffuse nontender thyromegaly, tachycardia, fever, exophthalmos, lid lag, hypertension, thinning hair, bone tenderness
1st investigation
- serum calcium:
elevated
- parathyroid hormone:
normal or suppressed
- thyroid stimulating hormone:
low
More
Other investigations
Hypervitaminosis A
History
history of excess vitamin A intake (usually supplementation), bone pain
Exam
bone tenderness, mucous membrane dryness (chronic toxicity)
1st investigation
- serum calcium:
elevated
- parathyroid hormone:
normal or suppressed
Other investigations
- vitamin A:
elevated
Milk-alkali syndrome
History
excess dietary milk or alkali (e.g., because of dyspepsia), excess calcium supplementation (e.g., in postmenopausal women), bone pain
Exam
non-specific findings
1st investigation
- serum calcium:
elevated
- parathyroid hormone:
normal or suppressed
Other investigations
Sarcoidosis
History
age 20-40 years, cough, dyspnoea, chronic fatigue, arthralgia, wheezing, photophobia, painful red eye, blurred vision; may be asymptomatic; family history of sarcoidosis
Exam
rhonchi, lymphadenopathy, erythema nodosum, lupus pernio, conjunctival nodules, facial palsy
1st investigation
- serum calcium:
elevated
- parathyroid hormone:
normal or suppressed
Other investigations
- chest x-ray:
hilar and/or paratracheal adenopathy with upper lobe predominant, bilateral infiltrates
More
Prolonged immobilisation
History
history of prolonged immobilisation in adolescent/young adult due to injury/neurological condition
Exam
non-specific findings
1st investigation
- serum calcium:
elevated
- parathyroid hormone:
nondetectable
Other investigations
Paget's disease
History
bone pain, affects pelvis in 75% cases, family history of Paget's disease, may be asymptomatic
Exam
bone tenderness, bone deformities, limping, increased local temperature, hearing loss
1st investigation
- calcium:
elevated
- parathyroid hormone:
nondetectable
- alkaline phosphatase:
markedly elevated[26]
- x-ray:
lytic changes in early stage; sclerotic picture predominates over osteolytic in later stage
Other investigations
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