GenMed - Endocrine

Question 1

Hyperthyroid

How do you investigate overt hyperthyroid

Answer 1

• if TSH is suppressed, but fT4 is normal: Check fT3.
• In overt hyperthyroidism but NO stigmata of grave’s disease: send TSH receptor ab to distibguish btw grave’s vs other aetiology.
• Radionuclide scan: Thyroid scintigraphy with technetium should be performed in patients with solitary thyroid nodule or MNG (multi-nodular goitre with low TSH.

[Source: Malaysia CPG 2019]

Question 2

Hyperthyroidism Treatment

Answer 2

1. Beta-adrenergic blockade = for ALL patients with:

• Symptomatic thyrotoxicosis, especially elderly.
• Resting HR > 90.
• CVD.

2. ATD:

• Carbimazole (CBZ) or
• Methimazole (MMI).

3. RAI therapy + replacement Thyroxine.
4. Thyroidectomy.

Question 3

ATD (Antihyroid drugs)

• How to start
• How to monitor
• How to adjust

Answer 3

ATD to use: (carbimazole or methimazole)

• CBZ is rapidly converted to MMI in the serum.
• 10 mg CBZ is metabolised to = 6 mg MMI.
• CBZ and MMI BOTH work same = Effective as OD dosing.
• Starting dose: 10-30 mg OD (chosen based on severity).
• Maintenance dose: 5-10 mg OD.

_ Monitoring_:

• Check fT3 AND fT4 at 2–6 weeks after initiation Rx (according to severity)
• fT4 levels may normalise despite persistent elevated fT3 (hence check both)
• TSH = NOT good to monitor, will remain suppressed for few months.
• Once euthyroid with the min ATD dose, review can be prolonged to 2–3 months
• When already long-term MMI (>18 months), increase review interval to 6 months.

Adjustment:

• Once euthyroid, reduce dose of MMI by 30%–50%
• Repeat biochemical test in 4–6 weeks.

[Source: Malaysia CPG 2019]

Question 4

Thyroid Storm

• Diagnosis + Score
• Score components (7)
• score interpretation (3)

Answer 4

Dx = Clinical diagnosis in a thyrotoxic patient with evidence of decompensation AND objective score:

1. Burch–Wartofsky Point Scale (BWPS)
2. Japan Thyroid Association (JTA) scoring.

BWPS Components:

1. Temp
2. HR.
3. AF.
4. Congestive Heart Failure.
5. CNS
6. GIT/hepato.
7. Precipitant history.

BWPS score interpretation:

• Score ≥ 45 = Thyroid storm.
• Score 25 – 44 = Impending thyroid storm.
• Score < 25 = UNLIKELY thyroid storm.

[Source: Malaysia CPG 2019]

Question 5

Ketosis

• Explain ketone in blood vs urine
• what conditions are assoc with +ve ketones (5)

Answer 5

Dipstick detects: Acetoacetate
Blood test detects: B-hydroxybutyrate (More specific)

POSITIVE test in:

• DKA.
• Starvation ketosis / prolonged fasting.
• Alcoholic ketoacidosis.
• Severe volume depletion.
• Isopropyl alcohol poisoning (rare)

Question 6

Osteoporosis / Osteopaenia

• How to diagnose

Answer 6

Clinical diagnosis:
Made after a low-trauma spine or hip fracture (equivalent to a fall from standing height or less), regardless of BMD score.

Diagnosis:
Diagnosed (gold standard) based on T-score of ≤ -2.5 on BMD measurement by DXA (dual-energy X-ray absorptiometry) at:

• Femoral neck.
• Total hip, or
• Lumbar spine.

[Source: MOH CPG Mx of OP 2022]

Question 7

Osteoporosis / Osteopaenia

• Treatment
• Prevention

Answer 7

Treatment:

1. Very high-risk individuals:
   Anabolic agent = Teriparatide
   I.e. r-PTH (Recombinant parathyroid hormone).
   Alternatively: (in order of preference)
   Denosumab or
   Bisphosphonates.
2. High-risk patiets: Use anti-resorptives:
   Bisphosphonates or
   denosumab.
3. Low-risk patients (if indicated, to consider):
   HRT (menopausal hormone replacement therapy) or
   SERM (Selective estrogen receptor modulators).

Cautious:

• Oral bisphosphonates = NOT recommended for eGFR < 30.
• Zoledronic acid = Contraindicated for eGFR < 35.
• Review bisphosphonate efficacy after 3-5 years.
• Denosumab ‘drug holiday’ NOT recommended ue to:
  i. Rebound increase in bone turnover and
  ii. Increased risk of multiple vertebral fractures.
• If denosumab is stopped, subsequent treatment option should be initiated (risk of rebound).

Prevention:

1. Screening:
   Recommended for individuals with:

• Prior low-trauma fractures.
• Clinical risk factors
• Secondary osteoporosis,
• Height loss and falls risk
  All age ≥65 yo should be screened ≥ annually for risk of falls.
  Hip protectors reduces the risk of hip fractures.
• All postmenopausal women ≥50 yo.

2. Adequate calcium and vitamin D.

• Ca supplements: ≥ 1200 mg/d of elemental calcium
• Vit D: ≥ 800 IU/day.

3. Regular physical activity, in particular weight-bearing exercise.
4. HRT for symptomatic women <60 yo AND within 10 years of menopause.
5. Tibolone for women who are 1 year past their last period.
6. Raloxifene for postmenopausal osteoporosis.

[Source: MOH CPG Mx of OP 2022]

Question 8

GIOP

• How to manage

Answer 8

1st line: Oral bisphosphonates
2nd line Denosumab
Others:
i. Teriparatide.
ii. IV bisphosphonates.
iii. Activated vitamin D.
IV: Raloxifene (if postmenopausal)

[Source: MOH CPG Mx of OP 2022]

Question 9

MOA of anti-OP

• Biphosphonates
• Denosumab
• Teriparatide.

Answer 9

Biphosphonates
= Inhibit osteoclastic bone resorption.

Denosumab
= Inhibits RANKL leading to inhibition of osteoclast recruitment, maturation and action
Slows bone resorption.

Teriparatide
= r-PTH (Recombinant parathyroid hormone)
Anabolic that stimulates osteoblastic activity > increase bone growth.