An unusual ca(u)se of tetany

Prof. S.SUNDAR’s unit,Dr. N.ARUN KUMAR, PG

Case presentation

Chitra 42/f – home-makerAdmitted with the c/o tonic contractions of both the ULs -10 days

h/o presenting illness

Pt was apparently normal till 1 year backc/o tonic contractions of both ULs

-around 10 episodes over past 1 yearIncreased frequency –for past 10 daysAfter developing each episodes –taken parenteral

drug in private hospital & got relieved of the symptom

No investigations done h/o generalized weakness & easy fatiguability

• Not associated with LOC• No h/o tonic clonic movement• No h/o tongue bite• No h/o aspiration• No h/o bladder / bowel incontinence• No h/o aura• No h/o fever• No h/o abdominal pain

Past history

Not a k/c of HTN/DM/CVA/CAD/seizures/PTNot a k/c of hypo/hyperthyroidismNo h/o major surgeryNo h/o chronic drug intakeNo h/o neck irradiation

Personal history• Mixed diet intaker• Normal regular menstrual cycles

Family history• No relevant family history

General examination

• Conscious, oriented, afebrile• No pallor/cyanosis/icterus/clubbing/PE/GLA

Vitals: PR-84/min; BP- 110/80 mmHg; RR-18/min; temp- 36.4

Systemic examination

• CVS- S1, S2 heard, no murmur• RS- NVBS +, no added sounds• Abdomen- soft; no organomegaly• CNS- NFND

Provisional diagnosis

TETANY FOR EVALUATION

Investigations CBC Values

HbTCDCESRRBCHCTPlatelet MCVMCHMCHC

11.8 gm%11000 cells/cummP51, L38, E6, M4, B14/104.4 million34.9%4.84 lakh79.3 fl26.8 pg33.8 gm/dl

Electrolytes ELECTROLYTES VALUES

Serum calcium-

Serum magnesium

Serum Na

Serum K-

Serum chloride

Serum HCO3

Serum PTH

Serum albumin

5.7 mg% (N – 8.7-10.2mg%)

1.2 mg% (N – 1.5-2.3mg%)

134 meq/L

2.92 meq/L

84 meq/L

34 meq/L

9.5 pg/ml (N – 8-51 pg/ml)

3.8gm/dl

ABG

• pH 7.486• HCO3 30.9• pCO2 41.8• K 1.26 mmol/L

• Metabolic alkalosis

• 24 hour urine Ca 46.2 mg (N – 100-321mg)• 24 hour urine Cl 323 meq (N – 110-250meq)

• RBS 77 mg%• Blood urea 22 mg%• Serum creatinine 1.0 mg%

• ECG – prolonged Q-T interval

DIAGNOSIS

GITELMAN’S SYNDROME

Gitelman’s syndrome

• Autosomal recessive condition also characterized by hypokalemic metabolic alkalosis, but with hypocalciuria & hypomagnesemia

Pathogenesis of Gitelman’s syndrome

Inactivating mutations in the gene

downregulation

Hypocalciuria Due to associated Plasma volumecontraction

Clinical features

Gitelman’s syndrome is mostly a disorder of adults

Laboratory evaluation

Treatment

• Magnesium aspartate (5-15 mmol Mg/day)• Magnesium oxide • Potassium supplements

Causes of hypocalcemiaLow PTH levels High PTH levelsParathyroid agenesis isolated DiGeorge syndrome

Vit. D def or impaired 1,25(OH)2 production/action nutritional vit.D def renal insufficiency with impaired 1,25(OH)2 production vit. D resistance

Parathyroid destruction surgical radiation infiltration by mets auto immune

PTH resistance syndromes PTH receptor mutations pseudo hypoparathyroidism

Reduced parathyroid function hypomagnesemia activating CaSR mutations

Drugs calcium chelators inhibitors of bone resorption (bisphosphonates, plicamycin) altered vit. D metabolism (phenytoin, ketoconazole)

Miscellaneous causes acute pancreatitis acute rhabdomyolysis hyngry bone syndrome osteoblastic mets (Ca prostate)

Causes of hypocalcemiaAssociated with normal / low plasma PO4

Associated with high plasma PO4

Associated with hypoalbuminemia

Vit. D def decreased intake decreased absorption (post-gastrectomy, PBC, intestinal malabsorption)

Idiopathic or sporadic hypoparathyroidism

Hemodilution

Decreased 25(OH) vit. D generation (liver disease, anti- convulsants)

Post operative hypo-parathyroidism

Nephrotic syndrome

Decreased calcitriol renal failure type 1 vit. D dep rickets

Acquired hypo- parathyroidism post irradiation amyloidosis

Exudative enteropathy

Resistance to calcitriol type 2 vit. D dep rickets

Pseudo hypo- parathyroidism type 1 type 2

cirrhosis

Acute pancreatitis CKD advanced stage

Mg deficiency AKI oligoanuric nstage

Clinical features

Symptoms of hypocalcemia depend on

RAPIDITY

SEVERITY

• Fatigue & muscular weakness• Increased irritability• Loss of memory• Confusion, hallucination, paranoia, depression• ECG manifestation of prolonged Q-T interval

Trousseau’s sign: carpal spasm induced by inflation of BP cuff to >20 mmHg of systolic BP for 3 min

Chvostek’s sign: tapping of facial nerve branches twitching of facial muscles)

Acute hypocalcemia

paraesthesias of the lips &

extremities

muscle cramps

tetany

laryngeal stridor convulsions

Chronic hypocalcemia

cataractsbrittle nails

with transverse

grooves

dry skin

decreased or even absent

axillary & pubic hair

Diagnostic approach to hypocalcemia

• Mesurement of serum Ca

• Measurement of serum PO4, Mg

Diagnostic approach to hypocalcemia

Treatment of hypocalcemia

Depends onRAPIDITY

SEVERITY

ACCOMPANYING COMLICATIONS

Treatment of acute symptomatic hypocalcemia

– Promptly correct symptomatic or severe hypocalcemia with cardiac arrhythmias or tetany with parenteral administration of calcium salts. Administer 1-2 ampules 10% calcium gluconate (93 mg/10

mL) in 50-100 mL of D5W over 5-10 minutes. Calcium chloride 10% solution (273 mg/10-mL ampule) delivers higher amounts of calcium and is advantageous when rapid correction is needed, but it should be administered via central venous access.

Measure serum calcium every 4-6 hours to maintain serum calcium levels at 8-9 mg/dL. If low albumin is also present, ionized calcium should be monitored.

Treatment of acute symptomatic hypocalcemia

(contd…)

Patients with cardiac arrhythmias or patients on digoxin therapy need continuous ECG monitoring during calcium replacement because calcium potentiates digitalis toxicity.

Identify and treat the cause of hypocalcemia and taper the infusion.

Start oral calcium and vitamin D treatment early. Patients with postparathyroidectomy hungry bone disease, especially those with osteitis fibrosa cystica, can present with a dramatic picture of hypocalcemia.

Treatment of chronic hypocalcemia:Treatment in PTH deficiency

Patients with hypoparathyroidism and pseudo-hypoparathyroidism can be managed initially with the oral administration of calcium supplements.

The hypercalcemic effects of thiazide diuretics may offer some additional benefits.

In patients with severe hypoparathyroidism, vitamin D treatment may be required; however, remember that PTH deficiency impairs the conversion of vitamin D to calcitriol.

Therefore, the most efficient treatment is the addition of 0.5-2 mcg of calcitriol or 1-alpha-hydroxyvitamin D3.

Treatment of chronic hypocalcemia(contd…)

Nutritional vitamin D deficiency from lack of sunlight exposure or poor oral intake of vitamin D: Ultraviolet light or sunlight exposure can treat these patients. Treat nutritional rickets with vitamin D2. Oral calcium preparations containing 1-2 g of elemental calcium per day can treat patients with a calcium deficiency. Calcitriol may be used, but it has the disadvantages of a higher price and the possibility of producing hypervitaminosis D with hypercalcemia.

Goal of treatmentTo bring serum calcium to low normal range

To avoid hypercalciuria

To avoid nephrolithiasis