Parathyroid Gland and its Disorders

ANATOMY
• Parathyroids are endocrine glands situated
behind the thyroid gland.
• They are four in number two on each side.
• Two upper glands are constant in position. It is
behind recurrent laryngeal nerve.
• Two lower glands are variable in position. It is
usually in front of the recurrent laryngeal nerve.
• Each gland weighs 40–50 mg. It is brownish
(khaki coloured) firm gland, which sinks in the
fluid unlike fat which floats.
• Blood supply :- Both superior and inferior
glands receive their blood supply from inferior
thyroid artery and its anastomotic branch.

DEVELOPMENT OF PARATHYROID GLANDS
• Superior Parathyroid glands
develop from 4th pharyngeal
pouch hence called as
parathyroid IV.
• Inferior Parathyroid glands
develop from endoderm of 3rd
pharyngeal pouch hence called
as parathyroid III.

PHYSIOLOGY
• Glands (chief cells) secrete parathormone
(PTH) which controls the calcium
metabolism.
• PTH converts vitamin D into 1, 25-
dihydrocholecalciferol in the kidney, an
active principle.
• PTH increases absorption of the calcium
from the gut.
• It mobilizes calcium from the bone.
• Increases the calcium reabsorption from the
renal tubules.

CALCIUM
• Total calcium in plasma in ionised and non-ionised (unbound and
bound) form is 8.5–10.2 mg/dl.
• 55% is bound; 45% is unbound ionised free active part (4.5–5.0 mg/dl).
• Commonest protein part of bound calcium is albumin (80%), remaining
is beta globulin, non-protein molecules.
• Level of Calcium is controlled by PTH, calcitonin and vitamin D acting
on bone, kidney and GIT.
• Calcium is important for blood coagulation, neuromuscular activity,
cellular activity, bone integrity.

HYPERPARATHYROIDISM (HPT)
TYPES :-
1. Primary :- unstimulated inappropriate high PTH secretion due to
hyperplasia or adenoma causing hypercalcaemia.
2. Secondary :- Due to chronic renal failure or due to malabsorption,
vitamin D deficiency rickets, i.e. due to chronic hypocalcaemia. There is
always parathyroid hyperplasia.
3. Tertiary :- Due to autonomous reactive hyperplasia of parathyroids
often seen like after renal transplantation.

PRIMARY HYPERPARATHYROIDISM (HPT)
• Primary HPT is 3rd most common endocrine disease after diabetes
and thyroid disease.
CAUSES :-
1. Adenoma (75–90%)
2. Hyperplasia (20–24%)
3. Carcinoma, rare (1%)

CLINICAL FEATURES
• Can be Remembered as Bones, stones, abdominal groans
and psychiatric moans.
• BONES :- Raised PTH causes increased osteoclastic activity
leading into decalcification of the bone resulting into bone
pain, sub periosteal erosions.
• STONES :- In the kidney due to hypercalcaemia, renal stones
(25%) develop, which are usually calcium phosphate or
oxalate type

• ABDOMINAL GROANS :- Hypercalcaemia stimulates gastrin release
which causes peptic ulceration. Hypercalcaemia can precipitate acute
pancreatitis. Gallstone disease is increased due to hypercalcaemia.
• PSYCHIATRIC MOANS :- Behavioural and neurotic problems with
depression, anxiety present as nonspecific symptoms.
• OTHER FEATURES :- Skin necrosis, corneal ulceration, band keratopathy
pseudogout, back ache, polyuria, polydypsia, constipation, glycosuria
and hypertension.

ACUTE HYPERPARATHYROIDISM (CRISIS)
• Causes :-
1. Sudden increase in PTH level due to rupture of parathyroid cyst or
bleeding in the parathyroid tumour.
2. Severe dehydration precipitates crisis.
3. Secondaries in bone (primary may be from breast).
Clinical features :-
Abdominal pain, vomiting, dehydration, oliguria, muscular weakness.
Serum Ca++ is very high > 12 mg%

TREATMENT OF CRISIS
• Forced diuresis using 3–5 litres of saline with frusemide.
• Rehydration using normal saline 300 ml/hour.
• Drugs to reduce Ca++ level, i.e. mithramycin, calcitonin, prednisolone,
bisphosphonates, Cinacalcet.
• Mithramycin rapidly controls the hypercalcaemia of malignant disease
but temporarily.
• Steroids inhibits effects of vitamin D. Dose is 400 mg/day IV for 5 days.
• Bisphonates like Clodranate, Pamidronate inhibits mobilization of the
calcium from the bone.
• Cinacalcet is calcium receptor agonist which reduces the serum calcium
level.

INVESTIGATION FOR HPT
• High serum calcium level more than 10 mg%.
• Serum albumin level also should be assessed to identify accurate ionic
calcium level.
• Serum phosphate level
• Increased serum PTH level is specific and diagnostic— > 0.5
• Bone density assessment.
• Vitamin D estimation.
• Increased urinary calcium level >250 mg/24 hours.
• Raised serum alkaline phosphatase level.

PARAMETERS PRIMARY HPT SECONDARY HPT
PARATHORMONE HIGH HIGH
CALCIUM HIGH NORMAL
PHOSPHATE DECREASED INCREASED

XRAY FEATURES
• Sub-periosteal erosion of radial side of
middle phalanx
• Calcification in bones
• Pepper lesions in the skull
Ultrasound abdomen to detect renal and
pancreatic disease
Ultrasound neck
CT/MRI scan neck and mediastinum.

SPECIAL INVESTIGATIONS
• Selective venous sampling for PTH.
• Thallium-Technetium scan shows hot spots
which is diagnostic of parathyroid adenoma.
• Technetium-99m labelled Sestamibi isotope.
It is often combined with single photon
emission computerised tomography (SPECT).
• Urinary cAMP level increases in 90% cases.
• Angiography, venous sampling, USG-guided
biopsy are other methods
TECHNETIUM 99m Labelled
SESTAMIBI

DIFFERENTIAL DIAGNOSIS
• Secondaries in the bone—due to secretion of PTH related polypeptide
by tumour.
• Multiple myeloma.
• Vitamin D intoxication.
• Sarcoidosis.
• Functioning carcinoma.
• Familial hypocalciuric hypercalcaemia is an autosomal dominant
disease with mild raise in serum calcium and PTH levels secondary to
mutation in the cell membrane calcium receptor.

TREATMENT
SURGICAL TREATMENT:- PARATHYROIDECTOMY
INDICATION FOR PARATHYROIDECTOMY :-
• Severe symptoms
• Young age group
• Markedly reduced bone density
• Serum calcium more than 11 mg%
• Urinary calculi
• Neuromuscular presentations
• Urinary calcium more than 400 mg /24 hour

PARATHYROIDECTOMY
• Surgical removal of the glands and implantation of fragments of the
gland in forearm muscle mass (brachioradialis) or neck
(sternomastoid).
• If it is carcinoma, additional hemithyroidectomy with postoperative
radiotherapy is required.
• Adenoma when occurs in one gland with normal other glands,
removal of that gland with adenoma may be sufficient.
• When all four glands are diseased, transcervical thymectomy is also
added along with total parathyroidectomy to reduce persistent and
recurrent disease.

NON SURGICAL CARE
• Good hydration,
• Regular exercise,
• Avoiding immobilisation,
• Daily calcium and vitamin D intake is done in patients who have recovered
from acute crisis.
• Estrogens reduce the calcium level and maintain bone density.
• Raloxifene, a selective estrogen receptor modulator is also reduces the
serum calcium level.
• Biphosphonates mainly alendronate improves the bone mineral density
(BMD) in primary HPT.
• Cinacalcet, a calcimimetic drug activate calcium receptor and reduces the
levels of PTH and calcium.

PARATHYROIDECTOMY
• Indications in Primary HPT
• Symptomatic HPT
• Asymptomatic HPT with — Criteria (2002) for surgical intervention are:
1. Raise in serum calcium level more than 1 mg/dl of upper limit of the
normal calcium range
2. 24 hour urinary calcium if more than 400 mg; creatinine clearance when
reduced more than 30%
3. Bone density greater than 2.5 standard deviations below peak bone mass
in lumbar spine/hip/lower end of radius
4. Age below 50 years
5. When medical therapy is not possible

PREOPERATIVE PREPARATION
Vocal cords should be assessed by preoperative indirect laryngoscopy.
High calcium levels preoperatively may require treatment with
• Hydration
• Diuresis
• Steroids (prednisolone 20 mg TID for 5 days before surgery)
• 100 mmol phosphate infusion in 6 hours.
• 200 units calcitonin subcutaneous injection for 5 days twice daily before
surgery.
• Biphosphanate—etiodronate disodium 7.5 mg/kg daily as slow IV infusion
for 3 days; mithramycin 25 µg/kg as single dose.

ANAESTHESIA AND POSITION
• General anaesthesia is used with neck hyperextension by placing
rolled sheet under the shoulder blades.
• Head is placed on the head ring.
• Head end of the table is raised to semi-erect position (SemiFowler
position).

INCISION AND DISSECTION
• Horizontal crease incision is done, two-finger breadth above the
sternal notch, from one sternocleidomastoid to the other (Kocher’s
thyroid incision).
• Strap muscles are separated after opening the deep fascia in the
midline.
• Thyroid gland is mobilised to identify the parathyroid adenoma.
• Parathyroid having adenoma is mobilised which is close to recurrent
laryngeal nerve.
• End artery of the parathyroid is identified and ligated.

• Adenoma is separated from adjacent thyroid tissue using gauze
dissection.
• Parathyroid may be confirmed by frozen section biopsy or on
table aspiration of parathyroid tissue which is analysed for PTH
assay which will be more than 1500 pg/ml
• Total parathyroidectomy is done for parathyroid hyperplasia by
removing all four glands and one-third of one gland is
autotransplanted into the forearm muscle (brachioradialis) or
sternocleidomastoid muscle with marker stitch.
• Gland to be transplanted is sliced into 1 mm pieces and around
18 pieces are embedded in decided muscle with a marker stitch
or clip

COMPLICATIONS
• Haemorrhage.
• Recurrent laryngeal nerve palsy.
• Hungry bone syndrome
• Severe hypocalcaemia is a problem when all glands are removed (3½)
with bilateral neck exploration.
• Migration or inability to identify the transplanted parathyroid is often a
problem in autotransplantation of parathyroid

HUNGRY BONE SYNDROME
• It occurs usually in patients with preoperative hyperthyroidism. They
have increased bone breakdown in their hyperthyroid state.
• When a patient’s thyroid hormone level drops acutely after surgery,
stimulus to break down bone is removed. The bones are now
“hungry” for calcium, remove calcium from the plasma rapidly.
• It usually occurs after parathyroidectomy; thyroidectomy for toxic
thyroid; prostate cancer patients on estrogen therapy.
• Sudden cessation of existing increased bone breakdown makes bones
to absorb calcium, magnesium and phosphorus rapidly.

• Hypocalcaemia, hypophosphataemia, hypomagnesemia and
hyperkalaemia are four typical features in these patients.
• Bone-specific alkaline phosphatase (ALP) continues to rise in the
first few weeks indicating increased bone reconstruction.
• Supplementation of vitamin D and elemental calcium is needed
during discharge for 6 months.
• Postoperatively they need calcitriol with 2 gm calcium
supplement.
• Monitoring is done by evaluating serum calcium, albumin,
magnesium, phosphorus and bone specific alkaline phosphatase.

EFFECTS OF SURGERY
• Among neuromuscular symptoms of primary HPT, proximal
muscle weakness responds better than respiratory muscle
weakness by parathyroidectomy.
• Among psychiatric illnesses, depression and spatial learning
and processing improve well by surgery.
• Bone mineral density in hip and lumbar spine becomes
better.
• Nephrocalcinosis is improved by surgery
• Operative failure rate is 1.5 to 6%.

SURGICAL APPROACHES
Classic approach (Traditional approach)
It is under general anaesthesia exploring bilateral neck to remove
parathyroid tissue which is confirmed by frozen section biopsy. It shows
95% cure rate with 2% complication rate
Minimally Invasive Parathyroidectomy (MIP)
It is done in case of single adenoma of parathyroid under regional
cervical block.

Median Sternotomy (3%)
Extension Median sternotomy is often needed when parathyroid is in
anterior mediastinum along with thymus.
Video-assisted Parathyroidectomy (Paolo Miccoli)
It is done in localised single adenoma using multiple ports on one side with
intermittent CO2 insufflation and suction irrigation.
Endoscopic Parathyroidectomy
Technique is limited to single adenoma to remove tumour and gland. Low
pressure insufflations with 5 mm four trocars are used.

Remedial Parathyroidectomy
It is done for persistent HPT or recurrent HPT. It is done through lateral
approach (Feind) between anterior margin of sternocleidomastoid and
strap muscles.
Subtotal Parathyroidectomy
It is indicated in hyperplasia or secondary HPT, wherein 3½ glands are
removed, retaining ½ of one gland.

Total Parathyroidectomy with Parathyroid
autotransplantation
• It is done alternatively in hyperplasia
wherein all four glands are removed
• It is removing all four glands and ½ or ⅓ of
one gland is autotransplanted into the
forearm muscle (brachioradialis) or
sternocleidomastoid muscle with marker
stitch.
• Transplanting gland is sliced into 1 mm
pieces and around 18 pieces are embedded
in decided muscle with a marker stitch or
clip.

MEN (MULTIPLE ENDOCRINE NEOPLASIA)
SYNDROME
Commonly inherited as an autosomal dominant.
Type—I: It is also called as Werner’s syndrome
Here the defect is in chromosome 11
It includes :-
• Parathyroid hyperplasia or adenomas
• Pituitary tumour
• Pancreatic tumour [Endocrine—Insulinoma, gastrinoma,
glucagonoma, vipoma..

Type—II: Also called as Sipple’s disease.
1. IIa
The defect is in chromosome 10.
It includes:-
• Medullary carcinoma of thyroid
• Phaeochromocytoma
• Parathyroid hyperplasia (50%).

IIb includes
• Medullary carcinoma of thyroid
• Phaeochromocytoma
• Mucosal neuromas in lips and eyelids with bumpy-lumpy lesions,
• Marfanoid face,
• Megacolon.

APUDOMAS
APUD (Amine Precursor Uptake Decarboxylation) cells are cells
having specific cytochemical characteristics. They are:
• High amine content.
• Capacity of amine precursor uptake.
• Property of decarboxylation of these precursors to form amines.
Cells share similarities in structure, properties, histological,
histochemical, immunocytochemical and electron microscopic
appearance.
Neuron specific enolase enzyme is specific for these cells

• Many of parathyroid tumours, pancreatic tumours are under this
group of APUDomas
• Their presentations are commonly due to increased secretions of
these neuroendocrine hormones.
• Commonly presentation is like syndromes. Insulinoma, glucagonoma,
gastrinoma, VIPoma are different examples.

• APUDOMAS are commonly associated with MEN syndrome
(commonly type I).
INVESTIGATION
• CT Neck
• MRI Abdomen
• Radioimmunoasaay
• TREATMENT is of individual diagnosed components of the condition.

HYPOPARATHYROIDISM
• Hypoparathyroidism is defined as a PTH level < 10 pg/ml (10 -65
pg/ml)
• Permanent hypoparathyroidism would be defined as requirement of
therapeutic vitamin D and/or calcium replacement at 6 months or
fasting albumin-corrected serum calcium below 8.0 mg/dl.

Temporary More common (2–50%)
average 10%
Usually lasts for 2 months maximum
up to 6 months. Decrease in
calcium.
Increase in phosphorous
Permanent
Less common (0.4–13%)
average 1%
Permanent— continues beyond 6
months.
Decrease in calcium
Increase in phosphorous
Hungry bone
syndrome
Common (5–13%) Severe, rapid begins in immediate
postop period. Decrease in calcium
Decrease in phosphorous

CAUSES
• Direct trauma to the parathyroid glands,
• Devascularization of the glands
• Removal of the glands during surgery like-thyroidectomy and
parathyroidectomy.

FEATURES OF HYPOPARATHYROIDISM
• Circumoral tingling, numbness, paraesthesia.
• Carpopedal spasm, laryngeal stridor.
• Respiratory muscle spasm, suffocation.
• Convulsions, blurred vision due to intraocular muscle spasm.
• Cataract formation as late feature.

TREATMENT
• Patients who have symptomatic hypocalcemia in the early
postoperative period or whose calcium levels continue to fall rapidly
need treatment.
• In symptomatic patients, intravenous calcium gluconate 10 ml 10%
solution (1 gm) is administered over 10 minutes.
• Calcium carbonate 1250 mg provides 500 mg of elemental calcium;
the patient should take 2500–5000 mg/day.
• The patient needs vitamin D supplementation with calcitriol 0.25–1
mcg/day

• Intravenous/intramuscular magnesium 0.5 gm/4 mEq/kg body weight
for 5 days, later magnesium gluconate tablets 500 mg orally.
• In 2 months, trial weaning of oral calcium can be made to identify
whether the hypoparathyroidism is temporary.
• Need for calcium supplementation longer than 6 months, indicates
permanent hypoparathyroidism.

PREVENTION OF HYPOPARATHYROIDISM
• Proper preoperative parathyroid localisation.
• Maintaining blood supply of parathyroids.
• Capsular ligation of the thyroid vessels at lower pole to retain
parathyroid end arteries.
• Parathyroid autotransplantation, if all 4 parathyroids are removed

TETANY
CAUSES:-
• After thyroidectomy (It is decreased level of parathormone in the
blood causing hypocalcaemia)
• Haemochromatosis,
• Wilson’s disease,
• DiGeorge’s syndrome.
• Severe vomiting,
• Metabolic alkalosis.
• Rickets, osteomalacia.
• Chronic renal failure.
• Acute pancreatitis.

FEATURES
• Circumoral paraesthesia, paraesthesia of neck,
fingers and toes.
• Twitching and weakness of tongue muscles,
muscles of forearm, hand, foot and digits—
carpopedal spasm.
• Fingers are extended except at the MCP joints
and thumb is strongly adducted
(obstetrician’s/accoucheur’s hand)
• Stridor and difficulty in breathing due to
paralysis of respiratory muscles.

• Chvostek‘s sign—Tapping above the angle
of the jaw to stimulate branches of facial
nerve causes the twitching of the angle of
mouth and eyelids
• Trousseau’s sign - Applying the
sphygmomanometer to the arm and
inflating the pressure more than systolic
pressure (200 mm of Hg) of the patient for
3 minutes can demonstrate carpal spasm.
• Generalised weakness and twitching all
over the body in severe cases mimicking
convulsions.

MANAGEMENT
• Serum calcium estimation is done. It will be less than 7 mg%.
• IV calcium gluconate 10% 10 ml 6th–8th hourly is given.
• Later oral calcium (1 gram three times daily) with vitamin D
supplementation (1–3 µg daily).
• Follow up at regular intervals by doing serum calcium level.
• Magnesium sulphate supportive therapy is also often needed—10 ml
10% magnesium sulphate intravenously

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