The symptoms and signs of hypercalcemia are now more often mild and general rather than severe renal and bone problems seen years ago:
GENERAL -symptoms such as malaise and depression
RENAL- renal colic from stones, polyuria/ nocturia, haematuria and hypertension.
BONES-bone pain.
ABDOMINAL-abdominal pain due to peptic ulceration.
In malignant diseases, hypercalcemia results from bony metastasis which indicates the malignant disease is of longstanding duration. Severe hypercalcemia is usually associated with malignant disease, hyperparathyroidism, renal dialysis or vitamin D therapy.
Corneal calcification is a marker of longstanding hypercalcemia. In primary hyperparathyroidism, only 5-10% have definite bony lesions and 20-40% renal involvement.
In longstanding cases of hypercalcemia, calcium starts getting deposited in soft tissues or can lead to renal stone formation.

• Weakness

  We report a case of a 39-year-old female with active systemic lupus erythematosus who complained of lethargy and weakness with a moderate renal impairment. Hypercalcemia was confirmed by laboratory examination. [ncbi.nlm.nih.gov]

  […] elevation in the concentration of calcium in blood Abnormally high concentration of calcium in the peripheral blood Abnormally high level of calcium in the blood Abnormally high level of calcium in the blood; manifestations include fatigability, muscle weakness [icd9data.com]

  Short-term or acute high levels of calcium can cause muscle twitching or weakness. Long-term high levels of calcium can lead to kidney stones, bone problems, and may intefere with mental abilities. [winchesterhospital.org]

• Fatigue

  Here, we report the case of a previously healthy 3-year-old who was admitted to the emergency room with fatigue, hyporeactivity, fever and limping gait that had evolved over 5 days and that was progressively worsening. [ncbi.nlm.nih.gov]

  Hypercalcemia, or calcium in systemic excess, is deleterious to the function of excitable membranes leading to skeletal muscle and gastrointestinal smooth muscle fatigue. [us.bestpractice.bmj.com]

  These symptoms are sometimes mistaken for other issues such as common fatigue and illness. [northwell.edu]

• Hodgkin Lymphoma

  […] production of 1,25 dihydroxyvitamin D by tumors – Hodgkins and some non-Hodgkins lymphoma. [errolozdalga.com]

  Angioimmunoblastic T cell lymphoma is a rare malignancy, accounting for only 2% of all non-Hodgkin lymphomas, first described in the 1970s and subsequently accepted as a distinct entity in the current World Health Organization classification. [ncbi.nlm.nih.gov]

  It is associated with both liquid malignancies, commonly multiple myeloma, leukemia, and non-Hodgkins lymphoma and solid cancers, particularly breast and renal carcinomas as well as squamous cell carcinomas of any organ. [dovepress.com]

  lymphoma Other factors that may increase your risk of hypercalcemia include: Cancer or treatment for cancer Genetic disorders Phosphate deficiency in newborns Kidney disease or failure Symptoms Symptoms may include: Bone pain Muscle weakness Constipation [uvahealth.com]

• Prolonged Immobilization

  Therefore, they are prone to the imbalance of osteoblastic and osteoclastic activity that occurs with prolonged immobilization, leading to hypercalcemia. [ncbi.nlm.nih.gov]

  Kidney failure, adrenal gland failure, hyperthyroidism, prolonged immobilization, use of a class of diuretics called thiazides, and ingestion of massive amounts of calcium (milk-alkali syndrome) are other potential hypercalcemia causes. [raysahelian.com]

  Kidney failure, adrenal gland failure, hyperthyroidism, prolonged immobilization, use of a class of diuretics called thiazides, and ingestion of massive amounts of calcium (milk-alkali syndrome) are other potential causes. [uclahealth.org]

• Congestive Heart Failure

  However, the aggressive hydration can exacerbate heart failure in elderly patients, the use of hydration is limited in patients with congestive heart failure. [oatext.com]

  One should exercise caution and administer smaller volumes of isotonic saline in patients with congestive heart failure or anuric renal failure, as they can become volume overloaded. [ascopubs.org]

  These methods are used for patients with renal insufficiency and congestive heart failure when saline infusion is not feasible. [clevelandclinicmeded.com]

• Dyspnea

  The most common serious adverse events were hypercalcemia worsening (5 patients, 15%) and dyspnea (3 patients, 9%). [ncbi.nlm.nih.gov]

  Symptoms attributable to hypercalcemia (see introduction) Presence of constitutional symptoms such as weight loss, fevers, fatigue Presence of bone pain Presence of easy bruising or bleeding (hematologic malignancy) Presence of cough, dyspnea or chest [clinicaladvisor.com]

  Respiratory insufficiency is signaled by dyspnea and increased work of breathing, retractions, orthopnea, and cyanosis. Upper airway obstruction is manifested by stridor and wheezing. [emedicine.medscape.com]

• Nausea

  She had nausea, vomiting, leg pain, polyuria, polydipsia, and muscle weakness. At the time of relapse, the ionized calcium level was 1.99 mmol/L. [ncbi.nlm.nih.gov]

  […] calcium in blood Abnormally high concentration of calcium in the peripheral blood Abnormally high level of calcium in the blood Abnormally high level of calcium in the blood; manifestations include fatigability, muscle weakness, depression, anorexia, nausea [icd9data.com]

• Vomiting

  Bob R is a 67 year-old man who presents to the emergency department with increasing abdominal pain and vomiting. His wife says he has been more confused over the past few days. Amongst other blood tests, his calcium returns at 3.2 mmol/L. [sharinginhealth.ca]

  These signs can include anorexia, gastroesophageal reflux, nausea, vomiting, lethargy or seizures or generalized irritability, and hypertension. [msdmanuals.com]

  She had nausea, vomiting, leg pain, polyuria, polydipsia, and muscle weakness. At the time of relapse, the ionized calcium level was 1.99 mmol/L. [ncbi.nlm.nih.gov]

• Constipation

  Symptoms of hypercalcemia include lethargy, mental imbalance, weakness, dehydration, constipation, nausea, diarrhea, and even heart arrhythmia. [ 1 ] When chronic constipation is associated with thyroid disorders, it is often attributable to hypercalcemia [globalhealingcenter.com]

  Gastrointestinal signs may occur (eg, anorexia, vomiting, constipation) and sometimes lethargy or seizures. Treatment is IV normal saline plus furosemide and sometimes corticosteroids, calcitonin, and bisphosphonates. [msdmanuals.com]

  D is a 60-year-old, African American woman who complains of long-standing constipation. Initial laboratory evaluation reveals a normal TSH, normal electrolytes, and a calcium level of 10.8 mg/dL (nl 8.4–10.2). [accessmedicine.mhmedical.com]

  […] blood Abnormally high concentration of calcium in the peripheral blood Abnormally high level of calcium in the blood Abnormally high level of calcium in the blood; manifestations include fatigability, muscle weakness, depression, anorexia, nausea, and constipation [icd9data.com]

• Abdominal Pain

  […] location of abdominal pain can provide information about what may be causing the pain. [en.wikipedia.org]

  His clinical course was favorable during the first few days -- abdominal pain and vomiting subsided, and oral feeding was restored. Nevertheless, his clinical status suddenly worsened, with abdominal pain and progressive consciousness deterioration. [scielo.isciii.es]

  Bob R is a 67 year-old man who presents to the emergency department with increasing abdominal pain and vomiting. His wife says he has been more confused over the past few days. Amongst other blood tests, his calcium returns at 3.2 mmol/L. [sharinginhealth.ca]

  She complained of severe myalgias, arthralgias, an inability to ambulate, nausea, vomiting, abdominal pain, and marked depression. [ncbi.nlm.nih.gov]

  pain, nausea and vomiting constipation kidney stones, renal failure pancreatitis polyuria, polydypsia (Calcium induced Diabetes insipidus) bradycardia AV block short qt Management: 1. [errolozdalga.com]

• Polydipsia

  She had nausea, vomiting, leg pain, polyuria, polydipsia, and muscle weakness. At the time of relapse, the ionized calcium level was 1.99 mmol/L. [ncbi.nlm.nih.gov]

  Case Report A 63 year old Mexican man with history of advanced prostatic adenocarcinoma and trans-urethral resection of prostate presented to ER with nausea, vomiting, polydipsia and altered mental status. [pubs.sciepub.com]

  For example, ingestion of most corticosteroid-containing creams or ointments usually results in only mild to moderate stomach upset, polydipsia, and polyphagia. [merckmanuals.com]

  History may also identify symptoms of high calcium such as renal stones typical of hyperparathyroidism, or lethargy, easy fatigue, confusion, depression, irritability, constipation, and polyuria and polydipsia. [us.bestpractice.bmj.com]

• Hypertension

  Exact pathophysiology remains unclear but is commonly associated with hypertension, renal failure, sepsis and use of immunosuppressive therapy. Its development in the setting of severe hypercalcemia is extremely rare. [ncbi.nlm.nih.gov]

  Common medications such as hydrochlorothiazide and other thiazide diuretics (prescribed for hypertension and edema), lithium, and excessive intake of vitamin D, vitamin A or calcium can result in hypercalcemia. [my.clevelandclinic.org]

  These signs can include anorexia, gastroesophageal reflux, nausea, vomiting, lethargy or seizures or generalized irritability, and hypertension. [msdmanuals.com]

• Muscle Weakness

  She had nausea, vomiting, leg pain, polyuria, polydipsia, and muscle weakness. At the time of relapse, the ionized calcium level was 1.99 mmol/L. [ncbi.nlm.nih.gov]

  weakness, depression, anorexia, nausea, and constipation High level of calcium in the blood Higher than normal levels of calcium in the blood. [icd9data.com]

  CKD‐MBD is characterized by high bone turnover, increased musculoskeletal morbidity including bone pain and muscle weakness, and vascular calcification which may contribute to the high incidence of cardiovascular disease and associated deaths. [web.archive.org]

  If the calcium level is very high or if symptoms of brain dysfunction or muscle weakness appear, fluids and diuretics are given by vein (intravenously) as long as kidney function is normal. [merckmanuals.com]

• Osteopenia

  […] hypoparathyroidism Subcutaneous fat necrosis Parathyroid hyperplasia Abnormal renal function Williams syndrome Idiopathic Maternal hypoparathyroidism or maternal hypocalcemia may cause secondary fetal hyperparathyroidism, with changes in fetal mineralization (eg, osteopenia [msdmanuals.com]

  Second, hypercalcemia may be found during evaluation of patients with symptoms or findings that can be related to hypercalcemia, such as constipation, weakness, fatigue, depression, nephrolithiasis, or osteopenia. [accessmedicine.mhmedical.com]

  Abstract Neonatal severe hyperparathyroidism (NSHPT) is a rare, life-threatening condition that presents with severe hypercalcemia, hyperparathyroidism, and osteopenia in the newborn period. [ncbi.nlm.nih.gov]

  […] levels are not dropping, if patient is in congetive heart failure. return to top Consequences and Course The consequences of hypercalcemia can include: cardiac: arrhythmias, QT shortening gastrointestial: pancreatitis, peptic ulcers musculoskeletal: osteopenia [sharinginhealth.ca]

• Suggestibility

  Lung uptake in bone scan may be a special and reliable clue suggestive of hypercalcemia. [ncbi.nlm.nih.gov]

  A raised alkaline phosphatase suggests bony metastases, sarcoidosis or thyrotoxicosis. A raised calcitonin level is suggestive of B-cell lymphoma. [patient.info]

• Psychiatric Manifestation

  If kidney impairment occurs as a result, manifestations can include increased urination, urination at night, and increased thirst.[6] Psychiatric manifestation can include emotional instability, confusion, delirium, psychosis, and stupor.[6] Limbus sign [en.wikipedia.org]

• Polyuria

  She had nausea, vomiting, leg pain, polyuria, polydipsia, and muscle weakness. At the time of relapse, the ionized calcium level was 1.99 mmol/L. [ncbi.nlm.nih.gov]

  […] increase in bone resorption Clinical Manifestations of Hypercalcemia: Neuro changes: confusion, ams, coma Psychosis GI ulcers (calcium increases gastric secretion) abdominal pain, nausea and vomiting constipation kidney stones, renal failure pancreatitis polyuria [errolozdalga.com]

  We describe a woman who had hypercalcemia associated with elevated serum concentrations of parathyroid hormone-related protein during pregnancy and lactation.Lethargy, thirst, polyuria, and nocturia developed in a 34-year-old woman who was 35 weeks pregnant [nejm.org]

  Symptoms are nonspecific and include fatigue, weakness, nausea, vomiting, abdominal pain, bone pain, polyuria and confusion, as well as coma in severe cases. [academic.oup.com]

• Nocturia

  We describe a woman who had hypercalcemia associated with elevated serum concentrations of parathyroid hormone-related protein during pregnancy and lactation.Lethargy, thirst, polyuria, and nocturia developed in a 34-year-old woman who was 35 weeks pregnant [nejm.org]

  The symptoms and signs of hypercalcemia are now more often mild and general rather than severe renal and bone problems seen years ago:GENERAL -symptoms such as malaise and depression RENAL- renal colic from stones, polyuria/ nocturia, haematuria and hypertension.BONES-bone [symptoma.com]

  The clinical manifestations of hypercalcemia include: Central nervous system effects include lethargy, impaired concentration, fatigue, and muscle weakness; Renal effects include dehydration, polyuria, nocturia, nephrolithiasis resulting from hypercalciuria [oatext.com]

  Impairment of the renal concentrating mechanism leads to polyuria, nocturia, and polydipsia. Elevation of serum calcium > 12 mg/dL ( > 3.00 mmol/L) can cause emotional lability, confusion, delirium, psychosis, stupor, and coma. [web.archive.org]

  Impairment of the renal concentrating mechanism leads to polyuria, nocturia, and polydipsia. Elevation of serum calcium > 12 mg/dL (> 3.00 mmol/L) can cause emotional lability, confusion, delirium, psychosis, stupor, and coma. [msdmanuals.com]

• Anuria

  The leading symptoms that characterize the crisis are oliguria and anuria as well as somnolence and coma. [jasn.asnjournals.org]

  [citation needed] Hypercalcaemic crisis [edit] A hypercalcaemic crisis is an emergency situation with a severe hypercalcaemia, generally above approximately 14 mg/dL (or 3.5 mmol/l).[7] The main symptoms of a hypercalcaemic crisis are oliguria or anuria [en.wikipedia.org]

• Lethargy

  We report a case of a 39-year-old female with active systemic lupus erythematosus who complained of lethargy and weakness with a moderate renal impairment. Hypercalcemia was confirmed by laboratory examination. [ncbi.nlm.nih.gov]

  These signs can include anorexia, gastroesophageal reflux, nausea, vomiting, lethargy or seizures or generalized irritability, and hypertension. [msdmanuals.com]

  […] malignancy commonly is the result of multiple myeloma, breast cancer, or lung cancer and is caused by increased osteoclastic activity within the bone. [4] The ED physician should be concerned about any patient with a history of cancer who presents with lethargy [web.archive.org]

• Irritability

  History may also identify symptoms of high calcium such as renal stones typical of hyperparathyroidism, or lethargy, easy fatigue, confusion, depression, irritability, constipation, and polyuria and polydipsia. [us.bestpractice.bmj.com]

  Here we present the case of an infant with hypercalcemia who presented with fatigue, irritability, and failure to thrive after prolonged immobilization. [ncbi.nlm.nih.gov]

  These signs can include anorexia, gastroesophageal reflux, nausea, vomiting, lethargy or seizures or generalized irritability, and hypertension. [msdmanuals.com]

• Altered Mental Status

  Posterior reversible encephalopathy syndrome is an encephalopathy that can be clinically characterized by headache, altered mental status and/or seizures. [ncbi.nlm.nih.gov]

• Stupor

  The sluggish nerves also explain drowsiness, confusion, hallucinations, stupor or coma. In the gut this causes constipation. Hypocalcaemia causes the opposite by the same mechanism. [en.wikipedia.org]

  Manifestations of Hypercalcemia Acute Chronic Gastrointestinal Anorexia, nausea, vomiting Dyspepsia, constipation, pancreatitis Renal Polyuria, polydipsia Nephrolithiasis, nephrocalcinosis Neuro-muscular Depression, confusion, stupor, coma Weakness Cardiac [ncbi.nlm.nih.gov]

  Elevation of serum calcium > 12 mg/dL ( > 3.00 mmol/L) can cause emotional lability, confusion, delirium, psychosis, stupor, and coma. Hypercalcemia may cause neuromuscular symptoms, including skeletal muscle weakness. [web.archive.org]

  Elevation of serum calcium > 12 mg/dL (> 3.00 mmol/L) can cause emotional lability, confusion, delirium, psychosis, stupor, and coma. Hypercalcemia may cause neuromuscular symptoms, including skeletal muscle weakness. [msdmanuals.com]

• Cognitive Impairment

  The elderly, and especially those with pre-existing dementia, are most at risk for drug induced acute confusional states.[6] New research is finding a link between Vitamin D deficiency and cognitive impairment (which includes 'foggy brain').[7] See also [en.wikipedia.org]

  Presentation of Hypercalcaemia At levels At levels At levels >3.5 mmol/L Polyuria and polydipsia Dyspepsia - due to calcium-regulated release of gastrin Depression Mild cognitive impairment All of the previous plus: Muscle weakness Constipation Anorexia [patient.info]

  Subtotal parathyroidectomy resulted in recovery of cognitive impairment. Primary hyperparathyroidism should be considered in a differential diagnosis of RPD. [jkna.org]

  The results of the physical examination are remarkable for weight loss, dehydration, and mild cognitive impairment. [ncbi.nlm.nih.gov]

Diagnosing the cause of hypercalcemia requires a complete physical history and examination which is a more complex process. [9]
Several fasting serum calcium and phosphate samples should be taken. Hypophosphataemia is common in primary hyperparathyroidism. If calcium levels are mildly elevated since long, malignancy is not likely to be the cause. Sudden onsets of elevated levels of calcium are suspected for malignancies. Most likely malignancies could be breast, lung, kidney multiple myeloma, lymphoma or leukaemias. Serum PTH levels should be measured; if high during hypercalcemia it definitely implies hyperparathyroidism.

Abdominal X-Rays show renal calculi or nephrocalcinosis. Renal function must be measured. Chest X-Ray should be done to rule out chest malignancies or sarcoidosis. Biopsy may also be done for sarcoidosis. Proteins electrophoresis should be done to confirm for myeloma. Serum TSH, T3 are necessary to diagnose underlying thyrotoxicosis. PTH reduces renal tubular reabsorption of bicarbonate, thus bicarbonate levels fall and plasma chloride levels rise in primary hyperparathyroidism.
If hyperparathyroidism is confirmed, the following tests may be useful in localization although adenomas are usually small-
Ultrasound for tumors
CT or MRI scans for better viewing and resolution.
Barium swallow may show indention of esophagus by adenoma.

• Nephrolithiasis

  Abstract Mutations of the CYP24A1 gene, encoding for the enzyme 25(OH)D-24-hydroxylase, can cause hypercalcemia, hypercalciuria, nephrolithiasis and nephrocalcinosis. [ncbi.nlm.nih.gov]

• Calcium Decreased

  Between one and three months postpartum, her serum calcium decreased from 11.4 to 10.2 mg/dL while her 1,25(OH)2 D level decreased from 83 to 24 pg/mL. Her 24-hour urine calcium was 277 mg. Six months postpartum, she became pregnant again. [ncbi.nlm.nih.gov]

  Any decrease in extracellular calcium ion concentration leads to an increase in PTH secretion. [emedicine.com]

  decreasing bone resorption and increasing renal calcium excretion. [endocrinologyadvisor.com]

• Short QT Interval

  The ECG shows: Bizarre-looking QRS complexes Very short QT interval J waves = notching of the terminal QRS, best seen in lead V1 Many thanks to Dr James Hayes, FACEM, for this fantastic ECG! [web.archive.org]

  Cardiovascular effects include prolonged PR interval, short QT interval, widened QRS complex, and bradycardia. Increased thirst with polydipsia and polyuria is seen initially, progressing to nephrolithiasis and nephrocalcinosis in chronic cases. [ncbi.nlm.nih.gov]

  Cardiac effects include short QT intervals, which may increase sensitivity to digitalis, and deposition of calcium in the heart valves, myocardium, or coronary arteries. [clevelandclinicmeded.com]

  Abnormal heart rhythms can also result, and ECG findings of a short QT interval[20] suggest hypercalcaemia. [en.wikipedia.org]

The main aim of treatment is first to bring down the levels of calcium followed by treating the underlying medical condition responsible for hypercalcemia. [10]
Hydration is very important as dehydration due to vomiting or renal impairment result in concentrated urine. An increased uptake of salt can help in increased excretion of sodium following increased potassium excretion. A loop diuretic can be give to sustain salt and water replacement preventing fluid overload. In addition loop diuretics also have inhibitory action on the calcium renal resorption. Thus, this helps, to further lower the calcium levels. With this treatment calcium levels can be bought down by 1-3 mg/dl within 24 hours. Caution should be taken to prevent magnesium or potassium depletion.

Second line of treatment includes biphosphonates [11] and calcitonin therapy. Bisphosphonates are taken by osteoclasts and prevent bone resorption. Bisphosphonates are contraindicated in renal failure patients. Calcitonin also prevents bone resorption and increases urinary excretion of calcium.

All cancer patients should receive bisphosphonates as the first line of treatment may not be possible to complete without any risks and side effects. Recurrence of hypercalcemia in such patients is inevitable.
Other therapies include use of glucocorticoids. Dialysis may be opted for in severe cases with renal failure. Supplementary phosphate therapy is recommended in case of low phosphate levels.

Indications for surgery in hyperparathyroidism remain controversial, but if needed should be done by a qualified surgeon. All agree that with renal disease or bone involvement, since there is no long term treatment requires surgery. Main complication of surgery is hypocalcaemia which should be carefully monitored.

The outlook of hypercalcemia mainly depends on the cause. Mild cases of hyperparathyroidism or hypercalcemia with a treatable cause have a good prognosis. Most cases have no complications at all.
Malignancies or granulomatous diseases associated with hypercalcemia usually do not do well, which is majorly due the underlying disease rather than hypercalcemia. The usual 30 day survival in malignancies is about 50%. Many cases of malignancies [8] in final stage show hospitalization due to an emergency. Thus mortality and morbidity mainly depend on the cause and are basically a reflection of how well the disease is treated or under control.

Major causes are primary hyperparathyroidism and malignancies. Hyperparathyroidism is the commonest cause. Other causes of hypercalcemia can be listed as follows

1. BONY RESORPTIVE HYPERCALCEMIA

• Excess PTH- primary hyperparathyroidism [3]. Primary hyperparathyroidism is very frequent in women above the age of 50. Primary hyperparathyroidism can occur when all the four parathyroid glands produce too much of PTH or one single gland starts producing an excess of PTH mainly due to an adenoidal tumor. Most of these are benign growths.
• Malignancies- over 20% cases with malignancies will develop hypercalcemia at some point in their disease condition. Secondary deposits of cancers of lung or the breast are also common causes. Production of osteoclastic factors by tumors as in case of multiple myeloma is another common cause.[4]
• Endocrine diseases- Thyrotoxicosis and Addision's disease
• Immobility over a long period of time 

2. GASTROINTESTINAL ABSORPTIVE HYPERCALCEMIA

• "Milk alkali” syndrome- an increase in calcium intake
• Sarcoidosis/ Paget's disease/ Tuberculosis
• Excess of vitamin D - iatrogenic or self administered.

3. RENAL RESORPTIVE HYPERCALCEMIA

• Medications - such as thiazides or lithium pills
• Familial hypocalciuric hypercalcemia
• Kidney failure

Hypercalcemia is a common clinical occurrence which has a long duration and is mostly mild. Postmenopausal women above the age of 50 are at a higher risk, as primary hyperparathyroidism is the most common etiological factor. [5]
It occurs in 1 in 1000 population, mainly affecting elderly females. Many a times, most cases go unnoticed. Hypercalcemia tends to occur with advancing age, where hyperparathyroidism and malignancy are the main reasons.
In cases of malignancy, hypercalcemia is frequently encountered as an endocrine electrolyte disorder in hospitalized patients. The occurrence in children is unknown and rare; it is also thought to be a rare occurrence in young adults.

The human skeleton stores 98% of total body calcium while the remaining 2% circulates through the body. Out of this 2%, half is bound to proteins such as albumin and globulin and the remaining is present in the free ionized form which has the physiological effects. Thus, measuring the free calcium level is more accurate. The level of circulating protein, mainly albumin, should also be taken into account for a correct measurement. The ionized calcium or the unbound calcium is physiologically important as it takes active part in cellular activities and neuromuscular functions. [6]
Corrected [CA] =Total [CA] + (0.8 x [4.5-albumin level])
An increase in bone resorption, increased gastrointestinal absorption or a reduced excretion of calcium by kidneys can cause hypercalcemia. Total serum calcium levels between 10.5 and 12 mg per dL are considered mild while levels above 14 mg per dL can be fatal and serious.
Generally when calcium levels fall, PTH [7] a hormone secreted by parathyroid glands increases calcium levels by stimulating bone resorption and accelerating tubular resorption of calcium. Calcitrol levels also increase thereby increasing calcium levels. As PTH increases calcium, it simultaneously causes an increased excretion of phosphate by the kidneys. Thus patients show low serum phosphate levels along with hypercalcemia. Along with this PTH also causes an increase in 1, 25 dihydroxy vitamin D synthesis further aggravating hypercalcemic state.
Calcium absorption from the gut is usually reduced. Impairment of glomerular filtration can also cause hypercalcemia.

The pathophysiology is varied and can be classified as three separate syndromes-

1.  the hypercalcemia of malignancy caused by systemic mediators
2. the hypercalcemia along with localized osteoclastic disease
3. the hypercalcemia associated with myeloma.

Increased bone resorption is the characteristic feature in all the three syndromes. In malignancies, tumor cells as well host cells stimulate humoral mediators which cause an enhanced activity of osteoclasts. This leads to hypercalcemia when the rate of entry of calcium in the blood increases in comparison to its removal from blood. Therefore when GI and osteoclastic bone absorption increases the levels of calcium, beyond the capacity of kidneys to eliminate it, that is when calcium enters the extra cellular fluid compartment and renal excretion or bone mineralization get impaired. Hypercalcemia is always preceded by hypercalciuria. When the kidney is unable to excrete the excess calcium, the patient develops hypercalcemia. A hypercalcemia state interferes with the action of ADH hormone on the distal tubule causing a state of nephrogenic diabetes insipidus resulting in polyuria. With the nausea and vomiting, thirst mechanism may not be active thus dehydration may occur.

There is no prevention for hypercalcemia other than early detection and treatment. An accurate diagnosis of the underlying cause will help to stabilize calcium levels faster. Any known history of hypercalcemia or hyperparathyroidism in the family should be mentioned to the physician for early screening and detection. Women above 50 should regularly check calcium levels if they show symptoms of hypercalcemia. Vitamin D and calcium supplements should be taken only under the guidance of a physician.

Hypercalcemia is a clinical condition characterized by elevated levels of calcium in the blood. It is much more common than hypocalcaemia and is frequently detected incidentally with multichannel chemical analyzers. The normal range of calcium is 9-10.5 mg/dl or 2.2-2.6mmol/L. Mild asymptotic hypercalcemia is mainly a laboratory finding and usually suggestive of some other disease which needs a careful work up and treatment. [1]
Calcium is a vital mineral of the body required for optimal functioning of the bones, muscles and nerves. The main regulators of calcium in the body are PTH, Vitamin D and calcitonin. Parathyroid hormone is released by parathyroid glands [2] which is the chief regulator of calcium in the body. Calcitonin is produced by specialized cells of the thyroid gland. Together these three hormones act on the kidneys, bones and GI tract to maintain levels of calcium in the blood stream. The simplest way to remember the presentation of hypercalcemia is by the phrase "moans, stones, groans and bones”. The intensity, duration and severity of this condition vary. The most common cause of hypercalcemia is hyperparathyroidism. Most cases of malignancies have hypercalcemia as an associated condition. Onset of hypercalcemia usually indicates a poor outlook for malignancies.
The options of treatment depend upon the severity and cause of hypercalcemia. Both medical and surgical modes of treatment are available. The outlook of this condition majorly depends upon the causation.

Hypercalcemia is a clinical condition where there are increased calcium levels in the blood. The normal levels of calcium in the body are 9-10.5mg/dL. Most times mild cases of hypercalcemia are not detected and go unnoticed. Calcium is an important mineral required by the body for smooth functioning of the bones, muscle, nerves and brain. Calcium is maintained in the body by three hormones which are PTH, Vitamin D and calcitonin. Any irregularity in these three causes calcium levels to fall or rise. The most common cause is the over activity of parathyroid glands which are four small glands situated near the thyroid gland which cause increase in PTH levels which thereby causes increased calcium levels. No obvious symptoms are seen, but slowly it can lead to major clinical conditions like tiredness, bony pains, alterations in blood pressure and bowel function. It is more common in menopausal women. A simple blood test can check blood calcium levels. A PTH level can also be checked for. Some scans maybe required incase of cancers or tumors. A consultation with your physician will help you control calcium levels. Treatment mainly involves lowering levels of calcium along with adequate hydration. Calcium and vitamin D supplements should always be taken under medical guidance.

1. Royer AM, Maclellan RA, Daniel Stanley J, Willingham TB, Heath Giles W. Hypercalcemia in the emergency department: a missed opportunity. Am Surg. Aug 2014;80(8):732-5.
2. al Zahrani A, Levine MA. Primary hyperparathyroidism. Lancet. Apr 26 1997;349(9060):1233-8.
3. Allerheiligen DA, Schoeber J, Houston RE. Hyperparathyroidism. Am Fam Physician. Apr 15 1998;57(8):1795-802, 1807-8.
4. Mundy GR, Guise TA. Hypercalcemia of malignancy. Am J Med. Aug 1997;103(2):134-45.
5. Luna-Cabrera F, Justicia-Rull EA, Caricol-Pérez MP, et al. Incidence of hypercalcemia, hypercalciuria and related factors in patients treated with recombinant human parathyroid hormone (1-84). Minerva Med. Apr 2012;103(2):103-10.
6. Pearce SH. Calcium homeostasis and disorders of the calcium-sensing receptor. J R Coll Physicians Lond. Jan-Feb 1998;32(1):10-4.
7. Strewler GJ. The physiology of parathyroid hormone-related protein. N Engl J Med. Jan 20 2000;342(3):177-85.
8. Alsirafy SA, Sroor MY, Al-Shahri MZ. Hypercalcemia in advanced head and neck squamous cell carcinoma: prevalence and potential impact on palliative care. J Support Oncol. Sep-Oct 2009;7(5):154-7.
9. Carroll MF, Schade DS. A practical approach to hypercalcemia. Am Fam Physician. May 1 2003;67(9):1959-66.
10. Inzucchi SE. Management of hypercalcemia. Diagnostic workup, therapeutic options for hyperparathyroidism and other common causes. Postgrad Med. May 2004;115(5):27-36.
11. Rogers MJ, Watts DJ, Russell RG. Overview of bisphosphonates. Cancer. Oct 15 1997;80(8 Suppl):1652-60.