Hypocalcaemia with Zonular Cataract Due to Idiopathic Hypoparathyroidism

Bilateral hypocalcaemic cataracts due to idiopathic parathyroid insufficiency: A case report

BACKGROUND

Hypoparathyroidism is uncommon, and cataracts secondary to hypoparathyroidism are even rarer. Herein, we report a case of bilateral cataracts following hypoparathyroidism.

CASE SUMMARY

A 27-year-old man presented to our hospital because of painless and progressive visual impairment of both eyes over two years. He was previously diagnosed with hypocalcemia but did not take calcium supplements regularly. He had no history of anterior neck thyroid surgery. After admission, the biochemical analysis indicated a serum calcium level of 1.21 mmol/L and an intact parathyroid hormone level of 0 pg/mL. Ocular examination revealed bilateral symmetrical opacity of the lens presenting as punctate opacity in the posterior subcapsular cortex together with radial opacity in the peripheral cortex (N1C2P3). Phacoemulsification with an intraocular lens was performed in both eyes sequentially. Postoperatively, the patient had a satisfactory recovery and greatly improved visual acuity.

CONCLUSION

This patient had hypocalcemia owing to idiopathic parathyroid insufficiency. Hypoparathyroidism may go unnoticed for years but with some latent clinical manifestations, such as bilateral symmetrical posterior subcapsular cataracts. This case report highlights that the cause of hypocalcemia in particularly young patients should be further investigated. Clinicians should be aware of hypoparathyroidism as a cause of bilateral cataracts. Early identification of hypoparathyroidism can save patients from further complications.

Idiopathic Hypoparathyroidism: Still a Diagnostic Conundrum - A Tertiary Centre Experience

Idiopathic hypoparathyroidism leads to hypocalcemia and hyperphosphatasemia and usually has a genetic aetiology. The variable but often subtle signs and symptoms usually lead to a misdiagnosis of hypoparathyroidism. Case records of 32 patients of idiopathic hypoparathyroidism admitted over a period of five years were analysed. There was a lag period of 5.94 years from the onset of symptoms to the diagnosis. Carpopedal spasm was the most common indication for admission to the hospital. Trivial symptoms such as fatigue (84%) and paresthesia (62.5%) were the most common reported symptoms. A sum of 46.5% of the patients were on antiepileptic drugs before the correct diagnosis of hypoparathyroidism was made. This observation emphasized that Calcium profile should be obtained in patients with history of paresthesia and seizure to avoid the long delay in diagnosis of hypoparathyroidism.

The effect of different analytical platforms and methods on the performance of population-specific adjusted calcium equation

Background

A recent attempt to improve the diagnostic value of adjusted calcium addressed a primary care-specific adjusted calcium equation, but validated the new equation for Roche Cobas, BCG and NM-BAPTA methods only. In this study, we aim to validate a population-specific equation for other methods and platforms.

Method

We collected retrospective patient data-sets from 15 hospital laboratories using a range of commercially available analytical platforms and methods for calcium and albumin measurements. Raw data-sets were collected and filtered according to Payne’s criteria, and separate adjusted calcium equations were derived for hospitalized and primary care patients.

Results

Mean albumin and calcium results were significantly higher in primary care populations ( P <  0.0001). The prevalence of hypocalcaemia using adjusted calcium ranged between 6% and 44% for inpatient data-sets and was higher in users of BCG methods. The application of community-specific adjustment equation to primary care data-sets reduced the prevalence of hypocalcaemia (mean 1.7%, range 0.8–3.7%).

Conclusion

We demonstrated that the use of a community-specific calcium adjustment equation to a primary care population reduces both the percentage and the variation of hypocalcaemia between different laboratories.

Idiopathic hypoparathyroidism in five cats

Idiopathic hypoparathyroidism was diagnosed in five young to middle-aged cats of mixed breeding. Three of the cats were male and two were female. Historic signs included lethargy (n = 5), anorexia (n = 5), muscle tremors (n = 4), weakness (n = 4), generalized seizures (n = 3), ataxia (n = 3), mental dullness or disorientation (n = 3), panting (n = 2), pruritus (n = 1), ptyalism (n = 1) and dysphagia (n = 1). Weakness (n = 4), dehydration (n = 2), cataracts (n = 2), hypothermia (n = 1), and bradycardia (n = 1) were found on physical examination. Results of electrocardiography revealed a prolonged Q-T interval in two cats. Results of initial laboratory tests revealed profound hypocalcemia and severe hyperphosphatemia with normal renal function. The diagnosis of hypoparathyroidism was made on the basis of the history, clinical signs, and results serum biochemical testing (i.e., severe hypocalcemia and hyperphosphatemia); in two cats, the diagnosis was also confirmed by histologic examination of parathyroid glands. Initial treatment included intravenous administration of 10% calcium gluconate and oral administration of large loading doses of calcium and vitamin D (dihydrotachysterol). Successful long-term management with dihydrotachysterol and calcium was achieved in all cats. The final dosage of dihydrotachysterol required to maintain normocalcemia in the five cats ranged from 0.004 to 0.04 mg/kg/day (mean = 0.015 mg/kg/day). Long-term calcium supplementation was given to three of the cats in dosages ranging from 29 to 53 mg/kg/day (mean = 42 mg/kg/day) of elemental calcium. One cat died after 28 months of therapy from widely metastatic hemangiosarcoma; the other three cats are still alive and well after 5 to 37 months of treatment.