# Subacute Thyroiditis

> Subacute thyroiditis for FMGE Medicine: painful gland, high ESR, low uptake thyrotoxicosis, steroid course and the Hashimoto variant.

- Canonical URL: https://prepelephant.com/topics/fmge/medicine/subacute-thyroiditis-fmge
- Exam / course: FMGE · Subject: Medicine
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Subacute Thyroiditis", PrepElephant, https://prepelephant.com/topics/fmge/medicine/subacute-thyroiditis-fmge

## Direct answer

Subacute (de Quervain, granulomatous) thyroiditis is a virus-triggered, painful inflammation of the thyroid — fever, neck pain radiating to the jaw or ear, a tender diffuse goitre, and a transient thyrotoxicosis caused by hormone leaking from destroyed follicles rather than by overproduction. The discriminating pair of tests is a suppressed thyroid-stimulating hormone with raised free T4 PLUS a near-absent radioactive iodine uptake, because the leaking gland cannot trap iodine; erythrocyte sedimentation rate and C-reactive protein are high, and thyroid antibodies are typically negative. Management is symptomatic: non-steroidal anti-inflammatory drugs for mild pain, prednisolone 20-40 mg daily tapered over weeks for severe pain, and a short beta-blocker for thyrotoxic symptoms — antithyroid drugs such as carbimazole do nothing, since no synthesis is occurring. Expect the four-phase course: thyrotoxicosis for weeks, a brief euthyroid interval, possible hypothyroidism for months, then recovery.

## What you must remember

- **Diagnosis in two sentences:** painful tender goitre with thyrotoxic biochemistry, high ESR/CRP, and LOW radioactive iodine uptake — contrast with Graves disease, where uptake is diffuse and high; a "thionamide-resistant thyrotoxicosis" is thyroiditis until this uptake logic is applied.
- **De Quervain features:** preceding upper respiratory infection, painful unilateral-dominant gland, pain referred to ear or jaw, fever; histology shows granulomas with giant cells — the pathology one-liner.
- **Four-phase timeline:** destructive thyrotoxicosis (2-8 weeks), euthyroid transition, hypothyroid phase (weeks to months, permanent in a minority), recovery — counsel patients accordingly.
- **Treatment ladder:** NSAIDs (indomethacin) for mild disease; prednisolone 20-40 mg daily with response within days, tapered over 2-6 weeks; propranolol 20-40 mg for adrenergic symptoms; NO carbimazole, no surgery, no radioiodine.
- **Hashimoto contrast:** painless goitre, raised anti-thyroid peroxidase antibodies, hypothyroidism the dominant phase (with transient "hashitoxicosis" in some), levothyroxine when permanent — the painless mirror image.
- **Other family members:** postpartum (lymphocytic) thyroiditis — thyrotoxic then hypothyroid phases within a year of delivery, treated symptomatically; drug-induced (amiodarone type 2, immune-checkpoint inhibitors, lithium); suppurative thyroiditis — hot, fluctuant gland with fever and high neutrophils, needing antibiotics and drainage, not steroids.
- **Steroid principle:** dramatic pain relief within 24-72 hours of prednisolone is itself characteristic; failure to respond should prompt reconsideration of suppurative disease or haemorrhage into a nodule.
- **India angle:** subacute thyroiditis is diagnosed late in busy clinics because the pain is attributed to pharyngitis; palpate the thyroid in every "sore throat with fever and palpitations" — a cheap clinical habit with a high diagnostic yield.

## A month in the life of the gland

A 38-year-old woman presents with 10 days of left-sided neck pain shooting to the ear, fever, palpitations and tremor after an upper respiratory infection. The left thyroid lobe is exquisitely tender; pulse 104 with fine tremor; free T4 high with TSH suppressed below 0.01 mIU/L; ESR 82 mm/hour. The clinical fork is overproduction versus destruction: a radioactive iodine uptake scan (or technetium pertechnetate, cheaper and widely available in India) shows virtually no uptake — destruction, not Graves disease. Management is NSAIDs with propranolol 20 mg thrice daily; because night pain keeps her awake, prednisolone 30 mg daily is added and tapered over four weeks. Carbimazole is explicitly withheld — the gland is a leaking warehouse, not an overactive factory, an explanation that doubles as viva practice.

Six weeks later she returns fatigued and gaining weight: TSH now 14 mIU/L with low free T4 — the hypothyroid phase. Levothyroxine starts at a low dose with review in three to six months, because most patients recover and stop it; a small proportion with persistent TSH elevation at a year remain permanently hypothyroid. Walking one patient through all four phases converts the textbook table into a remembered timeline — exactly what the exam stem asks you to reproduce.

## Where students slip

The most expensive error is treating destructive thyrotoxicosis with carbimazole: it cannot help (no hormone synthesis) and speeds the arrival of hypothyroidism; the question-writer plants a tender gland plus low uptake and waits for the wrong prescription. Second, the painless-versus-painful axis: de Quervain hurts, Hashimoto and postpartum do not, suppurative hurts with fever and needs drainage. Third, the uptake rule: high uptake means synthesis (Graves, toxic nodular), low uptake means leak (thyroiditis, exogenous intake, struma ovarii). Fourth, a thyrotoxic patient becoming hypothyroid on no therapy is the natural history, not a mistreatment. Finally, a tender gland with normal ESR should push suspicion towards haemorrhage or malignancy, not de Quervain.

## Frequently asked questions

### How does radioactive iodine uptake differentiate Graves disease from subacute thyroiditis?

Uptake is diffusely increased in Graves disease (active synthesis) and near-absent in subacute thyroiditis (destruction with hormone leak).

### What is the treatment of painful subacute thyroiditis?

Non-steroidal anti-inflammatory drugs for mild pain, prednisolone 20-40 mg daily tapered over weeks for severe pain, and propranolol for thyrotoxic symptoms — antithyroid drugs are ineffective.

### What histology defines de Quervain thyroiditis?

Granulomatous inflammation with multinucleated giant cells within the thyroid parenchyma, following a viral trigger.

### What is the natural course of subacute thyroiditis?

A thyrotoxic phase of several weeks, a transitional euthyroid period, a hypothyroid phase lasting months, and recovery in the majority of patients.

### How does postpartum thyroiditis present?

Painless thyrotoxicosis followed by hypothyroidism within a year of delivery, typically with positive thyroid antibodies and low radioactive iodine uptake during the toxic phase.