What’s Your Diagnosis?
Endocrinology Quiz
A 23 year-old woman presented with the chief complaints of bowed arms and legs, which started at the age of 4 to 5 years, accompanied by weakness of the thigh muscles. A review of systems indicated a history of dysuria, polyuria, constipation, and dyspepsia. Physical examination indicated the following: pulse, 86 beats/minute, blood pressure, 135/90 mm Hg; bilateral bowed legs and forearms; and (3/5) weakness of the proximal muscles of both legs. Laboratory studies disclosed the following values: calcium, 12.7 mg/dL (normal, 9 to 10.5 mg/dL); phosphorus, 1.7 mg/dL (3 to 4.5 mg/dL); alkaline phosphatase, 2,835 U/L (36 to 92 U/L); and intact parathyroid hormone by radioimmunoassay, 76 pg/mL (10 to 65 pg/mL). The radiologic findings are shown on the opposite page. What’s your diagnosis?
Answer
Hyperparathyroidism
The cinical picture of hyperparathyroidism can be described by the mnemonic Bones, Stones, abdominal Groans, and psychic Moans.”
Bones:
A pathognomonic radiologic bone abnormality is revealed by the subperiosteal erosions on the radial side of the middle phalanges of the hand (Figure 1). A pepper pot skull is illustrated in Figure 2 Deformities of the bone (osteitis fibrosa cystica) are shown in Figure 3
Figure 1.
Figure 2.
Figure 3.
Stones:
The manifestation of stones is indicated by renal calculi, nephrocaleinosis, and later renal failure (see opaque shadow in the right ureteric line in Figures 4 and 5).
Figure 4.
Figure 5.
Groans:
Groans refers to bouts of nausea, vomiting, dyspepsia, peptic ulcer, pancreatitis, and constipation.
Moans:
Moans alludes to depression and confusion.
Other symptoms include hypertension, proximal muscle weakness, and calcium deposition in the conjunctiva, usually at the limbus of the eye.
Hyperparathyroidism may be primary (adenoma, hyperplasia, functioning carcinoma), secondary (physiologic response to hypocalcemia caused by another disease, e.g., chronic renal failure, hypovitaminosis D), or lertiary (when chronic secondary hyperparathyroidism has resulted in an autonomous adenoma). Increased parathyroid hormone increases serum calcium by increasing calcium absorption from the gut, mobilizing calcium from bone, reducing renal calcium clearance, and also increasing renal phospbate clearance that may indirectly increase mobilization of calcium from bone.
Sarcoidosis is a chronic sysiemic granulomatous disease of unknown etiology, characterized histologically by the presence of noncaseating granulomas. It is also associated with hypercalcemia secondary to (a) abnormal vitamin D metabolism, (b) increased calcitriol production by sarcoid granuloma, and (c) increased gastrointestinal absorption.
Hypercalcemia is the most frequently encountered metabolic emergeney in oncology. Common tumors causing hypercalcemia include carcinomas of the breast, lung, and renal cell; squamous cell carcinoma of the head and neck; carcinoma of the esophagus; multiple myeloma; and thyroid cancer. The possible etiologies include production of growth factors from the malignant cells that activate osteoclast precursors to destroy surrounding bone, inhibition of osteoblast activity to allow the tumor cells to grow into the space destroyed by the osteoclast, and ectopic secretion of a parathyroid hormone-related pepride (as in squamous cell carcinoma of the head and neck, lung, and esophagus). The parathyroid hormone by radioimmunoassay helps in distinguishing hypercalcemia from hyperparathyroidism and from hyperparathyroidism caused by malignancy when the serum level is greater than 12 mg/dL. A very high level of urinary cyclic adenylic acid supports the diagnosis of primary hyperparathyroidism.
Familial hypocalciuric hypercalcemia is a benign autosomal dominant condition characterized by increased serum calcium, decreased uninary culcium, decreased frational secretion of calcium, and a normal parathynoid hormone level.
| Diagnosis | Serum Calcium | Serum PO4 | Alkaline Phosphatase | 24-Hr Urine Calcium |
|---|---|---|---|---|
|
| ||||
| Hyperparathyroidism | Increased | Decreased | Increased/normal | Normal/increased |
| Sarcoidosis | Increased | Increased/normal | Normal/increased | Increased |
| Malignancy | Increased | Normal/increased | Normal/increased | Increased |
| Familial hypocalciuric hypercalcemia | Increased | Decreased | Normal | Low (<150 mg) |
Contributor Information
Muhammad Wasif Saif, Third-Year Resident, Primary Care Intern, Medicine Residency Program, Univ. of Connecticut School of Medicine
James Bernene, Chief, Dept. of Medicine, New Britain General Hospital and Professor of Medicine, Univ. of Conn. School of Medicine, Farmington, CT
References:
- 1.Miller WR, Gefter WB, et al. : Benign lesions which simulate thoracic malignancy. Primary Care and Cancer 5:53–60, 1985 [Google Scholar]
- 2.Kao PC: Parathyroid hormone assay. Mayo Clin Proc 57:596, 1982. [PubMed] [Google Scholar]