Hypoparathyroidism (Tetany)MANAGEMENT

ENDOCRINE AND METABOLIC PRESENTATIONS · 12 SECTIONS

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614 items

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Cardiovascular Presentations71▾

Respiratory Presentations52▾

Neurological Presentations83▾

Gastrointestinal Presentations74▾

Genitourinary and Reproductive Presentations48▾

Infectious Disease Presentations148▾

Trauma Presentations89▾

Toxicologic Presentations80▾

Psychiatric Presentations26▾

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Dermatology Presentations23▾

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Hematologic and Oncologic Presentations36▾

Pediatric-Specific Presentations19▾

Endocrine and Metabolic Presentations45▾

Acute Porphyria Adrenal crisis Adrenal Insufficiency (Addisonian Crisis)Dehydration Diabetes Insipidus Diabetic Ketoacidosis (DKA)Euglycemic DKA (SGLT2 inhibitor)Galactosemia GLP-1 receptor agonist complications (retained gastric contents, aspiration risk)Homocystinuria Hypercalcemia Hyperkalemia Hypermagnesemia Hypernatremia Hyperosmolar Hyperglycemic State (HHS)Hypertensive emergency Hypertensive urgency Hypocalcemia Hypoglycemia Hypogonadism (Acute Presentation)Hypokalemia Hypomagnesemia Hyponatremia Hypoparathyroidism (Tetany)Insulin pump failure Maple Syrup Urine Disease (Crisis)Medium-Chain Acyl-CoA Dehydrogenase Deficiency (MCAD)Metabolic Acidosis Metabolic Alkalosis Myasthenia gravis crisis Myxedema coma Pellagra Pheochromocytoma (Crisis)Pituitary Apoplexy Pompe Disease (GSD II)Respiratory Acidosis Respiratory Alkalosis Scurvy SIADH Starvation Ketosis Tarui Disease (GSD VII)Thyroid storm Tyrosinemia Vitamin D Deficiency (Severe-Rickets)Von Gierke Disease (GSD I)

ENT and Maxillofacial Presentations27▾

Ophthalmologic Presentations19▾

Obstetric Presentations23▾

Systemic and Miscellaneous Presentations17▾

01Approach to the Critical Patient/attcp51

Airway and hemodynamic priorities

›Immediate airway threats

›Laryngospasm — highest acuity airway emergency in hypocalcemia

›Stridor, high-pitched inspiratory noise, aphonia

›If laryngospasm present, IV calcium gluconate 1–2 g over 10 minutes immediately

›Seizure activity from severe hypocalcemia

›Benzodiazepines for acute control; definitive treatment is IV calcium

›Airway positioning and suction ready

›Altered mental status with loss of airway reflexes

›Escalate to definitive airway management

›RSI preparation with anesthesia/critical care

›Hemodynamic targets

›QTc-prolongation-associated arrhythmia risk

›Continuous cardiac monitoring mandatory for all symptomatic patients

›Torsades de pointes — life-threatening; IV calcium is first-line reversal

›Hypotension

›MAP target >65 mmHg

›IV fluid resuscitation; consider vasopressor if refractory

Severity stratification

›Mild hypocalcemia

›Paresthesias only (perioral, fingertips)

›Corrected serum calcium 1.88–2.12 mmol/l (7.5–8.5 mg/dL)

›Oral calcium therapy appropriate

›Chvostek or Trousseau positive without active spasm

›Calcitriol 0.25–0.5 mcg BID initiation

›Close outpatient follow-up if tolerating PO

›Moderate hypocalcemia

›Sustained muscle cramps, Trousseau strongly positive

02History/hx65

Symptom onset and progression

›Neuromuscular symptom timeline

›Paresthesias — earliest symptom

›Perioral tingling

›Fingertip and toe numbness

›Progression pattern

›Mild tingling to sustained muscle cramps

›Carpopedal spasm

›Frank tetany in severe cases

›Laryngospasm

›Throat tightness, voice change, stridor

›Airway emergency — immediate IV calcium required

Triggers and precipitants

›Surgical history

›Recent anterior neck surgery

›Total thyroidectomy — 20–30% transient, 1–7% permanent hypoparathyroidism

›Parathyroidectomy, radical neck dissection

›Timing of symptom onset post-surgery

›Transient: hours to days postoperatively

›Persistent: >6 months postoperatively = permanent

›Physiologic stress triggers

›Febrile illness or infection

›Pregnancy or lactation

›Calcium demand increases dramatically

›Dose adjustment typically required

›Hyperventilation or anxiety

›Alkalosis lowers ionized calcium acutely

03Physical Exam/exam45

Vital signs and general appearance

›Vital sign assessment

›Heart rate

›Bradycardia or tachyarrhythmia possible in severe hypocalcemia

›Blood pressure

›Hypotension in severe cases

›Respiratory rate

›Stridor or increased work of breathing — laryngospasm

›SpO2

›Decreased with laryngospasm or bronchospasm

Neuromuscular examination

›Chvostek sign

›Technique: tap over facial nerve anterior to ear (preauricular)

›Positive: ipsilateral facial muscle twitching

›Present at baseline in up to 25% of normal adults — low specificity

›Sensitivity approximately 70% for symptomatic hypocalcemia

›Trousseau sign

›Technique: inflate BP cuff 20 mmHg above systolic for 3 minutes

›Positive: carpopedal spasm (wrist flexion, MCP extension, thumb adduction)

›More specific than Chvostek sign

›Sensitivity 94% for hypocalcemia, specificity 99%

›Spontaneous neuromuscular findings

›Hyperreflexia

›Muscle fasciculations

›Carpopedal spasm at rest

›Frank tetany — sustained involuntary muscle contraction

Airway examination

›Laryngospasm assessment

04Differential Diagnosis/ddx46

Life-threatening hypocalcemic causes

›Hypoparathyroidism (tetany)

›ICD-10: E20.9 (Hypoparathyroidism, unspecified)

›Low PTH, low calcium, elevated phosphorus

›Most common cause: post-surgical (75–78%)

›Hungry bone syndrome

›ICD-10: E83.51

›Post-parathyroidectomy or post-thyroidectomy for Graves disease

›Severe hypocalcemia with hypophosphatemia and hypomagnesemia

Secondary hypocalcemia

›Vitamin D deficiency

›ICD-10: E55.9

›Most common cause of hypocalcemia overall

›PTH elevated (secondary hyperparathyroidism) — distinguishes from hypoparathyroidism

›25-OH vitamin D low

›Hypomagnesemia

›ICD-10: E83.42

›Impairs PTH secretion and peripheral PTH action

›Must correct Mg before calcium will respond

›Causes: alcoholism, malnutrition, diuretics, cisplatin, aminoglycosides

›Chronic kidney disease

›ICD-10: N18.9

›Reduced 1-alpha hydroxylation of vitamin D

›Elevated PTH (secondary hyperparathyroidism)

›Creatinine elevated; phosphorus elevated

PTH-resistance syndromes

›Pseudohypoparathyroidism

›ICD-10: E20.1

05Laboratory Tests/lt51

Calcium assessment

›Serum calcium (albumin-corrected)

›Normal range 2.12–2.62 mmol/l (8.5–10.5 mg/dL)

›Correction formula: corrected Ca = measured Ca + 0.02 × (40 − albumin g/l)

›Hypoparathyroidism: corrected Ca typically <2.12 mmol/l (<8.5 mg/dL)

›Pitfall: albumin-corrected calcium unreliable in acidosis/alkalosis — use ionized Ca

›Ionized calcium (iCa)

›Normal 1.15–1.30 mmol/l

›iCa <1.1 mmol/l: clinically significant hypocalcemia

›iCa <0.75 mmol/l: severe; life-threatening arrhythmia risk

›Point-of-care measurement — fastest bedside confirmation

›pH-dependent: alkalosis reduces iCa; acidosis raises iCa

PTH and phosphorus

›Intact PTH (iPTH)

›Hallmark laboratory finding of hypoparathyroidism

›Low or inappropriately normal PTH in setting of hypocalcemia

›Normal range 1.6–6.8 pmol/l (15–65 pg/mL)

›Differential interpretation

›Low PTH + hypocalcemia = hypoparathyroidism or hypomagnesemia

›High PTH + hypocalcemia = vitamin D deficiency, CKD, pseudohypoparathyroidism

›Serum phosphorus

›Elevated in hypoparathyroidism (>1.45 mmol/l; >4.5 mg/dL)

›PTH normally promotes renal phosphaturia

›Absent PTH → phosphorus retention

›Low phosphorus suggests hungry bone syndrome or vitamin D deficiency

Magnesium

›Serum magnesium

›Must be checked in all hypocalcemia patients

06Diagnostic Tests/dt61

Scoring Systems

›Hypocalcemia severity classification

›Mild

›Corrected calcium 1.88–2.12 mmol/l (7.5–8.5 mg/dL)

›Paresthesias only; no neuromuscular signs

›Moderate

›Corrected calcium 1.63–1.88 mmol/l (6.5–7.5 mg/dL)

›Positive Chvostek or Trousseau; carpopedal spasm

›Severe

›Corrected calcium <1.63 mmol/l (<6.5 mg/dL)

›Tetany, laryngospasm, seizures, or QTc prolongation

›Trousseau sign — bedside diagnostic provocative test

›Inflate BP cuff 20 mmHg above systolic pressure for 3 minutes

›Positive: carpopedal spasm within 3 minutes

›Sensitivity 94%, specificity 99% for hypocalcemia

›More specific than Chvostek sign for clinical hypocalcemia

›Chvostek sign

›Tap facial nerve anterior to earlobe

›Positive: ipsilateral facial twitching

›Sensitivity ~70%; specificity limited (25% false-positive rate in normals)

MRI

›Brain MRI in chronic hypoparathyroidism

›Basal ganglia calcifications (Fahr syndrome pattern)

›Bilateral symmetric calcifications in putamen and globus pallidus

›May be associated with movement disorders, cognitive impairment

›White matter changes — less common

›MRI not required acutely; reserved for neuropsychiatric complications

›Spine MRI

07Disposition/dispo30

ICU and telemetry admission

›ICU admission criteria

›Active laryngospasm requiring airway intervention

›Seizures not controlled with initial IV calcium

›QTc >550 ms or torsades de pointes

›Corrected calcium <1.63 mmol/l (<6.5 mg/dL) with symptoms

›Hemodynamic instability

›Telemetry/step-down admission

›Corrected calcium <1.75 mmol/l (<7.0 mg/dL) requiring IV calcium drip

›Continuous cardiac monitoring for QTc during infusion

›Symptomatic hypocalcemia unable to tolerate oral intake

›Unstable calcium levels after IV bolus

›New diagnosis of hypoparathyroidism requiring workup

Floor admission

›General ward admission criteria

›IV calcium bolus administered with clinical improvement

›Transitioning to oral therapy

›Tolerating PO but requiring observation

›Electrolyte optimization ongoing (Mg replacement)

›Endocrinology consult for all admissions

›New diagnosis of hypoparathyroidism

›Refractory or recurrent hypocalcemia

Discharge criteria

›Safe discharge parameters

›Corrected calcium ≥1.88 mmol/l (≥7.5 mg/dL) and rising on oral therapy

›Symptom resolution or minimal paresthesias

›Tolerating oral calcium and calcitriol

›Reliable follow-up within 24–48 hours arranged

08Treatment/t79

Acute IV calcium replacement

›IV calcium gluconate (preferred for peripheral access)

›Acute bolus dosing

›1–2 g calcium gluconate (10–20 mL of 10% solution)

›93–186 mg elemental calcium per bolus

›Dilute in 50 mL D5W; infuse over 10–20 minutes

›Infusion rate

›Do not infuse faster than 1 g/10 min to avoid cardiac toxicity

›Rapid bolus risk: bradycardia, asystole

›Continuous calcium gluconate infusion

›0.5–1.5 mg/kg/hour elemental calcium

›Titrate to corrected calcium 2.0–2.25 mmol/l (8.0–9.0 mg/dL)

›Continuous cardiac monitoring required throughout

›Monitoring during infusion

›Serum calcium every 4–6 hours

›QTc trend on continuous cardiac monitor

›Magnesium and phosphorus levels

›IV calcium chloride (central line only)

›3× more elemental calcium per mL vs gluconate

›10 mL of 10% = 272 mg elemental calcium

›Reserve for cardiac arrest or critical emergency via central access

›Tissue necrosis risk if extravasation — must use central line

Magnesium correction

›Hypomagnesemia treatment

›Oral magnesium oxide

›400 mg PO daily to BID for mild to moderate deficiency

›Serum Mg target 0.75–0.95 mmol/l

›IV magnesium sulfate

›2 g IV over 15–20 minutes for severe deficiency or IV-only patients

›Repeat dose if Mg remains <0.6 mmol/l

›Rationale

›Hypomagnesemia blocks PTH secretion and receptor action

›Calcium will not normalize until Mg is corrected

Oral calcium and calcitriol initiation

›Oral calcium supplementation

›Calcium carbonate

›40% elemental calcium — first choice if normal gastric acid

›1,000–1,500 mg elemental calcium daily in divided doses with meals

›Avoid in patients on PPIs — requires acidic pH for absorption

›Calcium citrate

›21% elemental calcium — first choice in patients on PPIs or achlorhydria

›Does not require acidic pH

›1,000–1,500 mg elemental calcium daily in divided doses

›Separation from levothyroxine

›Take calcium at least 1 hour before or 3 hours after levothyroxine

›Calcitriol (active vitamin D)

›Initial dosing

›0.25 mcg PO BID — start low and titrate

›Titrate every 2–4 weeks by 0.25 mcg increments

›Typical maintenance dose 0.5–1.0 mcg BID

›Mechanism

›Bypasses PTH-dependent 1-alpha hydroxylation step

›Direct activation of intestinal calcium absorption

›Monitoring

›Serum calcium, phosphorus, creatinine, 24-hour urine calcium

›Hypercalciuria risk: target urine calcium <6.25 mmol/day

Refractory hypocalcemia management

›Thiazide diuretics

›Hydrochlorothiazide (HCTZ) 12.5–50 mg daily

›Reduces renal calcium excretion

›Indication: hypercalciuria on calcium/calcitriol therapy

›Monitor potassium and sodium

›Risk of hypokalemia and hyponatremia

›Optimize vitamin D stores

›Cholecalciferol (vitamin D3) supplementation

›Target 25-OH vitamin D 75–150 nmol/l (30–60 ng/mL)

›1,000–2,000 IU daily maintenance; 50,000 IU weekly for deficiency

›Phosphate management

›Dietary phosphate restriction (avoid processed foods, colas)

›Calcium carbonate as phosphate binder at meals if phosphorus persistently elevated

PTH replacement therapy

›Palopegteriparatide (Yorvipath)

›FDA-approved for chronic hypoparathyroidism in adults

›Indicated when conventional therapy (calcium + calcitriol) is inadequate

›Once-daily subcutaneous injection

›Mechanism

›Long-acting pegylated PTH(1-34) analog

›Physiologic PTH replacement — reduces supplement burden

›Dosing

›Starting dose 18 mcg SC once daily

›Titrate based on serum calcium response

›Monitoring

›Serum calcium daily initially; weekly after dose adjustment

›Reduce calcitriol and calcium supplements as PTH restores calcium

09Special Populations/sp65

Pregnancy

›Physiologic changes in pregnancy

›Calcium demands increase substantially in third trimester and lactation

›Fetal skeletal mineralization requires significant calcium transfer

›Breast milk calcium secretion: ~200–300 mg/day during lactation

›Calcitriol naturally increases in pregnancy

›Placental 1-alpha hydroxylation supplements renal production

›May reduce calcitriol dose requirements temporarily

›Management modifications

›Calcitriol dose often needs to increase in late pregnancy and lactation

›Monitor serum calcium monthly in second trimester; every 2 weeks in third

›Calcium supplementation target

›1,000–1,500 mg elemental calcium daily

›Prefer calcium citrate for bioavailability

›Avoid over-treatment

›Maternal hypercalcemia suppresses fetal parathyroid development

›Neonatal hypocalcemia risk from fetal gland suppression

›Palopegteriparatide safety in pregnancy

›Limited data; use only if benefits outweigh risks

›Conventional therapy preferred during pregnancy

›Neonatal considerations

›Infants of hypoparathyroid mothers at risk for hypocalcemia or hypercalcemia

›Neonatal calcium monitoring recommended

›Pediatric endocrinology alert at delivery

Geriatric

›Physiologic considerations

›Reduced gastric acid with age — calcium citrate preferred over carbonate

›Many elderly patients on PPIs

10Background/b65

Epidemiology

›Prevalence and incidence

›Estimated prevalence 23–37 per 100,000 person-years

›Rare endocrine disorder; approximately 70,000–80,000 cases in US

›Considered an orphan disease

›More common in women (female preponderance from post-surgical cases)

›Etiology distribution

›Postsurgical hypoparathyroidism — most common cause (75–78%)

›Total thyroidectomy: 20–30% transient; 1–7% permanent

›Radical neck dissection and parathyroidectomy also high risk

›Autoimmune hypoparathyroidism — most common non-surgical cause

›Isolated autoimmune or part of APS-1/APECED

›Anti-CaSR antibodies or anti-NALP5 antibodies

›Genetic causes

›22q11.2 deletion — most common in pediatric populations

›Activating CaSR mutations (autosomal dominant hypocalcemia)

›GCM2, GATA3 (HDR), AIRE (APECED), mitochondrial disorders

›Rare causes

›Iron or copper infiltration (thalassemia, hemochromatosis, Wilson disease)

›Metastatic disease to parathyroids

›Neck radiation

Pathophysiology

›Normal PTH physiology

›PTH secreted by chief cells of parathyroid glands in response to low calcium

›Acts on bone to mobilize calcium via osteoclast activation

›Acts on kidney to increase calcium reabsorption and promote phosphaturia

›Stimulates renal 1-alpha hydroxylase to convert 25-OH vitamin D to calcitriol

›Calcitriol enhances intestinal calcium and phosphorus absorption

›Consequences of PTH deficiency

›Hypocalcemia — decreased bone resorption, decreased renal reabsorption

›Ionized calcium falls — threshold for neuromuscular depolarization lowered

›Leads to increased excitability: paresthesias, tetany, seizures

›Hyperphosphatemia — lost PTH-driven phosphaturia

›Phosphorus binds calcium — further lowers ionized calcium

›Low calcitriol — impaired intestinal calcium absorption

›Increased bone mineral density paradoxically

›Low bone turnover without PTH-driven resorption

›Tetany mechanism

›Low ionized calcium destabilizes neuronal membranes

›Spontaneous repetitive discharge at lower threshold

›Peripheral nerves most sensitive: carpopedal spasm

›Central: seizures; airway: laryngospasm

›Alkalosis exacerbates: calcium binds albumin → ionized fraction drops

Therapeutic Considerations

›Treatment targets

›Serum calcium target: lower half of normal range

›Corrected calcium 2.0–2.25 mmol/l (8.0–9.0 mg/dL) — prevents hypercalciuria

›Urine calcium <6.25 mmol/day (<250 mg/day)

›Rationale for conservative calcium target

›No PTH-driven renal calcium reabsorption in hypoparathyroidism

›Higher serum calcium → hypercalciuria → nephrocalcinosis, nephrolithiasis, renal failure

›Conventional therapy limitations

›Calcium + calcitriol mimics PTH effect on intestine only

›Does not restore renal calcium reabsorption or bone remodeling

›High pill burden: multiple doses daily required

›Narrow therapeutic window — hypercalciuria common

›Long-term complications

›Nephrocalcinosis and nephrolithiasis in up to 30–40% on conventional therapy

›Renal insufficiency with prolonged disease

›Basal ganglia calcifications, cataracts in chronic disease

›PTH replacement rationale

›Palopegteriparatide restores full physiologic PTH axis

›Reduces urinary calcium excretion by restoring renal tubular reabsorption

›Lowers supplement requirements

›PaTHway Phase 3 trial: 70% of patients achieved normal calcium without supplements

›Monitoring on PTH replacement

›Daily calcium monitoring initially

›Gradual reduction of calcium and calcitriol supplements

11Patient Discharge Instructions/pdi26

copy discharge instructions

›What you have been diagnosed with

›Hypoparathyroidism with low blood calcium (tetany)

›Your parathyroid glands are not making enough PTH hormone

›This causes your calcium level to fall, causing muscle cramps and tingling

›You are being discharged with calcium and vitamin D medications to keep your calcium normal

›Your medications at home

›Calcium supplement — take with meals, not all at once

›Spread doses throughout the day for best absorption

›If you take thyroid medication, take calcium at least 1 hour before or 3 hours after

›Calcitriol (vitamin D) — take as prescribed, do not stop without calling your doctor

›Magnesium supplement if prescribed

›Diet instructions

›Eat calcium-rich foods: dairy products, fortified foods, leafy green vegetables

›Avoid large amounts of phosphate-rich foods: processed foods, dark colas

›Stay well hydrated to protect your kidneys from calcium deposits

›Follow-up plan

›Blood test to check calcium within 24–48 hours of discharge

›Follow-up with endocrinology for ongoing management

›Regular monitoring of calcium, kidney function, and urine calcium

›Return to emergency department immediately for

›Muscle spasms that do not resolve or are getting worse

›Difficulty breathing, throat tightness, or voice changes

›Seizure or loss of consciousness

›Palpitations, fast or irregular heartbeat

›Confusion or unusual behavior

›Numbness or tingling that is spreading or severe

12References/r30

Guidelines and key sources

›Gafni RI, Collins MT. Hypoparathyroidism. New England Journal of Medicine. 2019

›Comprehensive clinical review; epidemiology, pathophysiology, management

›NEJM 2019; 380:1738-1747

›Khan S, Khan AA. Hypoparathyroidism: Diagnosis, Management and Emerging Therapies. Nature Reviews Endocrinology. 2025

›Current diagnostic criteria, conventional and PTH replacement therapy

›PubMed PMID 39905273

›Clarke BL, Brown EM, Collins MT, et al. Epidemiology and Diagnosis of Hypoparathyroidism. Journal of Clinical Endocrinology and Metabolism. 2016

›Prevalence data 23–37 per 100,000; etiologic distribution

›J Clin Endocrinol Metab. 2016;101(6):2284-2299

›Orloff LA, Wiseman SM, Bernet VJ, et al. American Thyroid Association Statement on Postoperative Hypoparathyroidism. Thyroid. 2018

›Surgical risk data: 20–30% transient; 1–7% permanent hypoparathyroidism

›Thyroid. 2018;28(7):830-841

Landmark trials and consensus statements

›Khan AA, Ali DS, Bilezikian JP, et al. Best Practice Recommendations for Diagnosis and Management of Hypoparathyroidism. Metabolism. 2025

›Serum calcium targets, urine calcium monitoring, PTH replacement guidance

›PubMed PMID 40581321

›Khan AA, Rubin MR, Schwarz P, et al. PaTHway Phase 3 Trial: Palopegteriparatide in Hypoparathyroidism. Journal of Bone and Mineral Research. 2023

›70% normalization without supplements; renal calcium reduction

›JBMR 2023; doi:10.1002/jbmr.4741

›Tsourdi E, Amrein K, Meier C, et al. Consensus-Based Recommendations for Diagnosis, Treatment, and Monitoring of Hypoparathyroidism. Calcified Tissue International. 2025

›DACH region consensus; monitoring intervals, complication screening

›PubMed PMID 40794165

›Shoback DM, Bilezikian JP, Costa AG, et al. Presentation of Hypoparathyroidism: Etiologies and Clinical Features. Journal of Clinical Endocrinology and Metabolism. 2016

›Clinical features, signs, symptom prevalence

›J Clin Endocrinol Metab. 2016;101(6):2300-2312

›Sell J, Ramirez S, Partin M. Parathyroid Disorders. American Family Physician. 2022

›Differential diagnosis algorithm; primary care perspective

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