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Quinshett’s Disease (Hypocalcemia)

Overview

Quinshett’s disease is a historic eponym for a form of chronic hypocalcemia that was first described by Dr. L. Quinshett in the early 20th century. Modern textbooks no longer use the term, but the condition is still relevant because it represents a persistent deficiency of ionized calcium in the blood, often associated with impaired parathyroid hormone (PTH) function, vitamin D deficiency, or renal disease.

Hypocalcemia (low serum calcium) is a metabolic disturbance that can affect anyone, but it is most common in:

• Adults over 50 years (especially women post‑menopause)
• Patients with chronic kidney disease (CKD) or end‑stage renal disease
• Individuals taking medications that interfere with calcium metabolism (e.g., bisphosphonates, anticonvulsants, proton‑pump inhibitors)
• People with malabsorption syndromes (celiac disease, inflammatory bowel disease) or severe vitamin D deficiency

According to the National Health and Nutrition Examination Survey (NHANES), serum calcium < 8.5 mg/dL (the threshold for hypocalcemia) is found in approximately 2–3 % of the U.S. adult population, with higher rates in patients with CKD (up to 25 %).<sup>1</sup>

Symptoms

Symptoms stem from the role of calcium in neuromuscular excitability, cardiac conduction, and bone metabolism. Not all patients experience every sign, and the severity often correlates with how quickly calcium levels fall.

Neuromuscular

• Paraesthesias: Tingling or “pins‑and‑needles” sensations, most often around the mouth, fingertips, and toes.
• Muscle cramps & spasms: Sudden, painful contractions (often in the calves or back).
• Carpopedal spasm (Tetany): Involuntary flexion of the hands and feet; “hand‑flap” sign.
• Facial grimacing (Chvostek sign): Twitching of facial muscles when the facial nerve is tapped.
• Seizures: Rare but can occur in severe or rapidly developing hypocalcemia.

Cardiovascular

• Prolonged QT interval on ECG, predisposing to torsades de pointes.
• Palpitations, dizziness, or syncope in severe cases.

Gastrointestinal

• Nausea, vomiting, and loss of appetite.
• Constipation (due to reduced smooth‑muscle contractility).

Skeletal

• Bone pain or fragility fractures with chronic hypocalcemia.
• Osteomalacia in long‑standing vitamin D deficiency.

Psychiatric / Cognitive

• irritability, anxiety, or depression.
• Confusion or memory problems when calcium is markedly low.

Causes and Risk Factors

Hypocalcemia is a final common pathway of several distinct pathophysiologic mechanisms.

Primary Causes

1. Parathyroid hormone deficiency or resistance (primary hypoparathyroidism):
• Post‑surgical removal or damage to the parathyroids (thyroidectomy, parathyroidectomy).
• Autoimmune destruction or genetic mutations (e.g., CASR gene).
• Familial hypoparathyroidism.
2. Vitamin D deficiency or metabolism disorders:
• Limited sun exposure, malabsorption, or chronic kidney disease (impairs conversion to active calcitriol).
• Medications: anticonvulsants (phenytoin, phenobarbital), glucocorticoids.
3. Renal failure (chronic kidney disease stage 3‑5):
• Decreased 1‑α‑hydroxylase activity → low calcitriol.
• Phosphate retention → calcium‑phosphate bind causing secondary hyperparathyroidism, but early CKD can present with low calcium.
4. Magnesium deficiency:
• Hypomagnesemia impairs PTH secretion and action.
5. Acute pancreatitis:
• Saponification of calcium in inflamed peripancreatic fat.

Risk Factors

• Neck surgery (thyroid, parathyroid, or extensive neck dissection).
• Long‑term use of loop or thiazide diuretics.
• Chronic use of proton‑pump inhibitors (decrease calcium absorption).
• Alcohol dependence (malnutrition, vitamin D deficiency).
• Rare genetic syndromes (e.g., DiGeorge syndrome, Barakat syndrome).

Diagnosis

Diagnosing hypocalcemia involves confirming a low serum calcium level and determining the underlying cause.

Laboratory Evaluation

1. Total serum calcium – measured in mg/dL; adjusted for albumin (or use ionized calcium).
2. Ionized calcium – the physiologically active fraction; preferred when albumin is abnormal.
3. Parathyroid hormone (PTH) – high in secondary hyperparathyroidism, low or inappropriately normal in hypoparathyroidism.
4. 25‑Hydroxyvitamin D – assesses vitamin D status.
5. 1,25‑Dihydroxyvitamin D (calcitriol) – especially in CKD.
6. Serum phosphate, magnesium, and creatinine – to evaluate renal function and electrolyte interactions.
7. Alkaline phosphatase – may be elevated in bone turnover disorders.

Additional Tests

• Electrocardiogram (ECG) – look for a prolonged QT interval.
• Bone densitometry (DEXA) – if chronic hypocalcemia raises suspicion for osteomalacia or osteoporosis.
• Genetic testing – when familial hypoparathyroidism is suspected.

Diagnostic Criteria

Most guidelines define hypocalcemia as ionized calcium < 1.12 mmol/L (4.5 mg/dL) or total calcium < 8.5 mg/dL after correcting for albumin. Clinical context determines whether the condition is acute (e.g., postoperative) or chronic (e.g., CKD‑related).

Treatment Options

Treatment aims to raise serum calcium to a safe level, alleviate symptoms, and address the root cause.

Acute Management (Emergency)

1. Intravenous calcium gluconate – 10 mL of 10 % solution (≈ 1 g calcium) given slowly over 10 minutes; may repeat until symptoms improve.
2. Continuous cardiac monitoring for arrhythmias.
3. Correct concurrent magnesium deficiency (IV magnesium sulfate) if present.

Chronic Management

• Oral calcium supplements: Calcium carbonate (500 mg elemental calcium) or calcium citrate (300 mg). Doses 1–2 g elemental calcium daily, divided with meals.
• Active vitamin D analogs: Calcitriol (0.25–1 µg daily) or dihydrotachysterol, especially in hypoparathyroidism or CKD.
• Thiazide diuretics: Low‑dose thiazide (e.g., hydrochlorothiazide 12.5–25 mg) can reduce urinary calcium loss in select patients.
• Magnesium repletion: Oral magnesium oxide or IV MgSO₄ if serum Mg < 1.7 mg/dL.
• Management of underlying disease: Optimize CKD care, adjust offending medications, treat malabsorption, or provide surgical correction if parathyroid tissue is removed unintentionally.

Special Situations

Condition	Preferred Therapy
Post‑surgical hypoparathyroidism	Calcium + active vitamin D; consider recombinant human PTH (rhPTH 1‑84) if refractory.
CKD‑related hypocalcemia	Calcitriol + phosphate binders; careful monitoring to avoid hyperphosphatemia.
Vitamin D deficiency	Cholecalciferol (Vitamin D₃) 1000‑2000 IU daily plus calcium.

Living with Quinshett’s Disease (Hypocalcemia)

Long‑term control requires a partnership between you, your primary care provider, and any specialists (endocrinology, nephrology). Below are practical tips for daily life.

Medication Adherence

• Take calcium carbonate with meals to enhance absorption; avoid taking it with high‑iron or high‑phosphate foods.
• Active vitamin D should be taken with calcium; some formulations are combined (e.g., calcitriol‑calcium tablets).
• Set a daily alarm or use a pill‑box to prevent missed doses.

Dietary Recommendations

• Include calcium‑rich foods: dairy (milk, cheese, yogurt), fortified plant milks, leafy greens (collard, kale), tofu, and canned fish with bones.
• Ensure adequate vitamin D: fatty fish, egg yolks, fortified cereals, and sensible sunlight exposure (10‑15 minutes mid‑morning, 2–3 times/week).
• Limit excessive phosphates (soft drinks, processed meats) which can bind calcium.
• Maintain adequate magnesium intake: nuts, seeds, whole grains, legumes.

Lifestyle & Monitoring

• Regular blood tests: calcium, phosphorus, magnesium, PTH, and vitamin D every 3–6 months (more often after medication changes).
• Annual bone density scan if you have chronic hypocalcemia or CKD.
• Stay hydrated; dehydration can concentrate serum calcium and precipitate cardiac arrhythmias.
• Exercise safely—weight‑bearing activities improve bone health, but avoid extreme endurance sports that may cause electrolyte swings without proper replacement.

Psychosocial Support

Living with a chronic electrolyte disorder can be stressful. Consider joining patient support groups (e.g., National Osteoporosis Foundation, Chronic Kidney Disease networks) and discuss anxiety or mood changes with a mental‑health professional.

Prevention

Because many cases are secondary to other conditions, prevention focuses on modifiable risk factors.

• Pre‑operative screening of calcium, vitamin D, and PTH before thyroid or parathyroid surgery.
• Limit long‑term use of medications that interfere with calcium (e.g., high‑dose PPIs) when alternatives exist.
• Maintain adequate vitamin D levels year‑round, especially in older adults and those with limited sun exposure.
• Manage chronic kidney disease aggressively—control blood pressure, avoid nephrotoxic drugs, and follow dietary phosphate restrictions.
• Ensure balanced nutrition in individuals with malabsorption or bariatric surgery; supplement with calcium citrate and vitamin D as directed.

Complications

If hypocalcemia is not corrected, several organ systems can be affected.

• Neuromuscular tetany – severe spasms that can impair breathing.
• Cardiac arrhythmias – prolonged QT leading to torsades de pointes and sudden cardiac death.
• Osteomalacia & fractures – chronic bone demineralization, especially in vitamin D deficiency.
• Dental abnormalities – enamel hypoplasia, increased caries risk.
• Cognitive impairment – chronic low calcium linked to memory deficits and mood disorders.
• Renal calcifications – paradoxically, over‑correction with calcium supplements in CKD may precipitate nephrocalcinosis.

When to Seek Emergency Care

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References:
1. National Health and Nutrition Examination Survey (NHANES). 2022. Calcium status in U.S. adults.
2. Mayo Clinic. Hypocalcemia (low blood calcium). 2023.
3. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Primary hypoparathyroidism. 2022.
4. Cleveland Clinic. Vitamin D deficiency and bone health. 2023.
5. UpToDate. Approach to the adult with hypocalcemia. 2024.

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