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Calcaneal osteotomy
A calcaneal osteotomy is a surgical cut of the heel bone (calcaneus) that realigns a flatfoot or cavovarus hindfoot, turning the Achilles tendon into a corrective force.
Calcaneal spur
Calcaneal spur (heel spur, Kalkaneussporn): a bony outgrowth from the heel bone at the plantar fascia or Achilles attachment, present in about 15% of people, linked to plantar fasciitis and age, usually painless.
Calcaneus
The calcaneus, also known as the heel bone or os calcis, is the largest tarsal bone, forming the heel, bearing most body weight, and anchoring the Achilles tendon.
Calcifediol
Calcifediol (25-hydroxyvitamin D3, calcidiol) is the liver-made circulating metabolite of vitamin D3 and precursor of calcitriol, used as a supplement and as RAYALDEE for CKD secondary hyperparathyroidism; it raises serum 25(OH)D faster and about 3.2-fold more potently than cholecalciferol.
Calcific pancreatitis
Calcific pancreatitis (chronic calcific pancreatitis, ICD-11 DC32.0): chronic pancreatitis with calcium carbonate deposits in pancreatic ducts and tissue; alcohol and smoking double calcification risk; surgery relieves pain better than endoscopy.
Calcific panniculitis
Calcific panniculitis (石灰化脂肪織炎), ICD-11 EB90.41, is calcium deposition in subcutaneous fat causing firm masses on thighs and hips, linked to hyperparathyroidism and chronic renal failure, and distinct from calciphylaxis.
Calcific tendinitis
Calcific tendinitis (calcific tendinopathy, calcifying tendinitis): hydroxyapatite calcium deposits in rotator cuff tendons, usually self-limiting, peaking in the fifth decade, treated first conservatively; lavage benefit questioned by a 2023 sham-controlled trial.
Calcification
Calcification: calcium buildup that hardens body tissue, normal in bones and teeth, abnormal (ectopic) elsewhere. Classified as dystrophic, metastatic, or ossification; driven by cell-mediated mechanisms, inhibited by pyrophosphate.
Calcifying aponeurotic fibroma
Calcifying aponeurotic fibroma (juvenile aponeurotic fibroma, Keasbey tumor) is a rare benign, locally aggressive fibroblastic tumor of the hands and feet in children, marked by calcified nodules, FN1-EGF fusion, and about 50% recurrence after excision.
Calciphylaxis
Calciphylaxis (calcific uremic arteriolopathy), a rare disorder of skin vessel calcification causing ischemic necrosis, mainly in dialysis patients; mortality 40-60%, risk factors include warfarin, hyperparathyroidism, diabetes; no proven treatment.
Calcipotriol
Calcipotriol, known in the United States as calcipotriene, is a synthetic vitamin D3 analog used topically to treat plaque psoriasis, with effects on skin but little impact on calcium metabolism.
Calcitonin
Calcitonin (thyrocalcitonin) is a 32-amino-acid peptide hormone from thyroid C cells, discovered by Copp in 1962, that lowers blood calcium by inhibiting osteoclastic bone resorption; used in Paget's disease, hypercalcemia, and osteoporosis.
Calcitonin gene-related peptide
Calcitonin gene-related peptide (CGRP), a 37-amino-acid neuropeptide from the calcitonin gene (alpha and beta isoforms), is a potent vasodilator whose CLR/RAMP1 receptor is the target of migraine drugs (gepants, monoclonal antibodies).
Calcitriol
Calcitriol (1,25-dihydroxyvitamin D) is the active form of vitamin D, formed by kidney hydroxylation, used as a vitamin D receptor activator to suppress PTH in CKD stages G3b–G5, with noted eGFR and creatinine effects.
Calcium channel blocker
Calcium channel blocker (calcium antagonist): drug blocking L-type voltage-gated calcium channels in heart and vascular smooth muscle; classes dihydropyridine and non-dihydropyridine; used for hypertension, angina, arrhythmia; discovered mid-1960s from coronary dilator screening.
Calcium deficiency
Calcium deficiency, also called hypocalcemia when blood calcium falls below 8.5 mg/dL, is low calcium intake or blood level causing neuromuscular irritability, tetany, and bone disease such as osteoporosis, rickets, and osteomalacia; ICD-11 code 5B5K.1.
Calcium glubionate anhydrous
Calcium glubionate anhydrous (calcium gluconogalactogluconate, UNII 3CF7K0SD0Q) is a water-soluble calcium salt of gluconic and lactobionic acids used as an oral syrup and injectable supplement for hypocalcemia, with only 7% elemental calcium by weight.
Calcium gluceptate
Calcium gluceptate, also known by the international nonproprietary name calcium glucoheptonate, is a soluble calcium salt used as a supplement to treat and prevent hypocalcemia.
Calcium gluconate
Calcium gluconate, the calcium salt of gluconic acid, is an IV and oral calcium replenisher for hypocalcemia, hyperkalemia cardiotoxicity, and hydrofluoric acid burns; first isolated 1880, US approval 1941, safer than calcium chloride peripherally.
Calcium metabolism
Calcium metabolism, also called calcium homeostasis, is how the body keeps blood calcium within a narrow range, regulated by PTH, vitamin D, and bone, kidney, and intestine.
Calcium pyrophosphate dihydrate crystal deposition disease
Calcium pyrophosphate dihydrate crystal deposition disease (CPPD, pseudogout) is crystal arthritis from CPP crystals in joints, mainly in older adults; phenotypes include acute arthritis, chronic arthritis, OA with CPPD, and crowned dens syndrome; no disease-modifying therapy exists.
Calcium release deficiency syndrome
Calcium release deficiency syndrome (CRDS) is a rare autosomal dominant arrhythmia caused by RyR2 loss-of-function variants, causing sudden cardiac death with negative exercise stress tests, distinct from CPVT, with a candidate post-pause T-wave diagnostic test.
Calculus (dental)
Dental calculus, or tartar, is mineralized plaque biofilm adhering to tooth crowns, roots, or prostheses. A secondary factor in periodontal disease removed by scaling, it also preserves ancient DNA, diet, and disease markers.
Calculus in bladder
Calculus in bladder (bladder stone, vesical calculus): hard mineral mass forming in the urinary bladder, usually from incomplete emptying; classified primary, secondary, or migratory; treated by cystolithotripsy.
Calculus in urethra
A calculus in the urethra, also called urethrolithiasis, is a urinary stone lodged in the tube that carries urine from the bladder, usually presenting as acute urinary retention.
Calculus of kidney
Calculus of kidney (renal stone, ICD-11 GB70.0): a mineral concretion in the renal collecting system, mostly calcium-based, diagnosed by non-contrast CT, treated with NSAIDs, SWL, URS, or PCNL, and recurrent in up to 39% at 15 years.
Calculus of lower urinary tract
Calculus of lower urinary tract (ICD-11 GB71): stones in the bladder or urethra, also called vesical or urethral calculi; bladder stones are about 5% of urinary stones, mostly secondary to bladder outlet obstruction, treated by transurethral cystolithotripsy.
Calculus of prostate
Calculus of prostate (prostatic calculi, prostatolithiasis, ICD-11 GA91.3): small calcium carbonate or calcium phosphate calcifications forming in the prostate, common in men over 50, usually asymptomatic, not independent predictors of severe LUTS.
Calculus of upper urinary tract
Calculus of upper urinary tract (ICD-11 GB70) covers kidney and ureteral stones, mostly calcium oxalate. Key facts: 106 million 2021 incident cases, 45% ultrasound sensitivity, PCNL for stones over 2 cm.
Calculus of ureter
Calculus of ureter (ureterolithiasis, ureteric stone; ICD-10-CM N20.1, ICD-11 GB70.1) is a urinary stone, usually formed in the kidney, lodged in the ureter, causing renal colic; passage rates and treatment depend on stone size and location.