Case study- Hypercalcemia

Case Details

A 35 year -old female reported to emergency with severe pain in the left flank region, which was radiating towards the lower leg and back. The patient was in acute distress and agony. History revealed that she frequently suffered from urinary tract infections and had several such episodes of pain. She further reported that she constantly felt weakness, fatigue and bone pains from the previous few months.

There was no history of fever and there was no personal or family history of medical problems.

Her physical examination was normal except for tenderness in the left renal region. The attending physician ordered for complete blood count, electrolytes and a complete urinalysis.

The laboratory investigation report revealed a normal complete blood count (CBC), and significantly elevated calcium level and low phosphorus level. Urine was cloudy and had plenty of pus cells. The patient was admitted and treated for renal colic.

What is the underlying cause of repeated episodes of renal colic?

What is the most likely diagnosis?

What is the relationship between bone pains and frequent urinary tract infections in this patient?

What is the cause for high serum calcium and low phosphorus level in this patient?

Case details Hypercalcemia, hypophosphatemia, recurrent urinary tract infections, renal stones, and bone pains all signify underlying hyperparathyroidism. (Cloudy urine and pus cells are indicative of urinary tract infection).

Hyperparathyroidism is overactivity of the parathyroid glands resulting in excess production of parathyroid hormone (PTH). The parathyroid hormone regulates calcium and phosphate levels.  

Hyperparathyroidism is classified into three categories-

1) Primary hyperparathyroidism-Primary hyperparathyroidism results from a hyperfunction of the parathyroid glands themselves. There is over secretion of PTH due to adenoma, hyperplasia or, rarely, carcinoma of the parathyroid glands.

2) Secondary hyperparathyroidism-Secondary hyperparathyroidism is the reaction of the parathyroid glands to hypocalcemia caused by something other than a parathyroid pathology, e.g.chronic renal failure or vitamin D deficiency.

3)Tertiary hyperparathyroidism- Tertiary hyperparathyroidism results from hyperplasia of the parathyroid glands and a loss of response to serum calcium levels. In cases of long-standing secondary hyperparathyroidism, the hypertrophied parathyroid glands can become autonomously functioning and continue to secrete PTH independent of whether the original stimuli to secrete PTH are still present.

In all cases, the raised PTH levels are harmful to the bone, and treatment is often needed.

Serum calcium- In cases of primary hyperparathyroidism or tertiary hyperparathyroidism heightened PTH leads to increased serum calcium (Hypercalcemia) due to:

1. increased bone resorption, allowing the flow of calcium from bone to blood
2. reduced renal clearance of calcium
3. increased intestinal calcium absorption

By contrast, in secondary hyperparathyroidism effectiveness of PTH is reduced.

Serum phosphate

In primary hyperparathyroidism, serum phosphate levels are abnormally low as a result of decreased renal tubular phosphate reabsorption. However, this is only present in about 50% of cases. This contrasts with secondary hyperparathyroidism, in which serum phosphate levels are generally elevated because of renal disease.

Manifestations of hyperparathyroidism involve primarily the kidneys and the skeletal system. Kidney involvement is due to either deposition of calcium in the renal parenchyma or to recurrent nephrolithiasis. Renal stones are usually composed of either calcium oxalate or calcium phosphate. In occasional patients, repeated episodes of nephrolithiasis or the formation of large calculi may lead to urinary tract obstruction, infection, and loss of renal function. 

Nephrocalcinosis may also cause decreased renal function and phosphate retention.

There are great variations in the manifestations. Patients may present with multiple signs and symptoms, including recurrent nephrolithiasis, peptic ulcers, mental changes, and, less frequently, extensive bone resorption.

Treatment and monitoring Treatment depends upon the severity and cause of the condition. If there is mildly increased calcium levels due to primary hyperparathyroidism and no symptoms, just regular check-ups are needed. If symptoms are present or calcium level is very high, surgery may be needed to remove the parathyroid gland that is overproducing the hormone. Treatment of secondary hyperparathyroidism depends on the underlying cause. Vitamin D and Phosphorus supplementation can also be done. 

Calcimimetics

Calcimimetics (cinacalcet) is a new type of drug for people with primary and secondary hyperparathyroidism on dialysis. It mimics the effect of calcium in tissues. This reduces PTH release from parathyroid glands, leading to lower calcium and phosphorus levels in the blood. 

Surgery for hyperparathyroidism may lead to low blood calcium levels, which causes tingling and muscle twitching. This requires immediate treatment.