Teaching File
Institute of Radiology "P. Cignolini" - University of Palermo, Italy
Post Partum Thyroiditis
Dipartimento di Endocrinologia - Ospedale V. Cervello - Palermo, Italy
May 16, 1996
Post-partum Thyroiditis (PTT) is a thyroid pathology recognised and studied only in the last decade. Its incidence varies, according to different authors, from 1.9 % to 10 %. This pathology can be considered to be a "complication" of pregnancy and generally becomes manifest after "puerperium". The cause of this illness is likely to be connected with a bounce effect of auto immune processes occurring after childbirth. PPT often appears with a slight increase in the volume of thyroid accompanied with pale symptoms such as: tiredness, asthenia, nervousness, palpitation or even more generic symptoms often classified as post-partum depression.
Findings
Diffuse vascolarization in the Echo color-Doppler examination
Thyreocites with regressive change
Mature lymphocytes
Blastic forms
Multinucleate cell
The case
A woman of 31 came to our observation because of increased volume in her neck; 5 months before she had carried her second pregnancy through. Good general conditions. She reported that in the days following the birth she was tense, had palpitation of the hearth and slight digital tremors. These symptoms had lasted for about two weeks. At the outpatient check up she reported a slight asthenia. Positive familiarity with thyroid desease. She didn't come from an endemic area. Objectively, an increased gland, both in volume (2nd OMS) and in consistence, was palpable. The clinical signs of alterated thyroid functions were absent. BP 130/70 mmHg, HR 78 p/m'.
At the echographic examination, the gland appeared increased in volume in toto. Low grade of diffuse echogenicity without signs of chronic thyroiditis fibrosis. An autoimmune thyroid desease was diagnosed.
Echo color-Doppler: diffuse vascularization
Hormonal examination: fT3 2.1 pg/ml, fT4 12.0 pg/ML, basal TSH 5.5 mcU/ml, 35 mcU/ml 20' minutes after TRH test with a value of 12 mcU/ml after 120 minutes, TPO 1:1200.
Cytological examination: picture of thyreocites with regressive change and mature lymphocytes and blastic forms, a few multinucleate cells, cellular debris; the picture was compatible with an autoimmune thyroiditis except for the presence of multiinucleate cells which are considered to be patognomic of sub-acute thyroiditis.
Therapy: L-Tiroxina (100 mcg/day).
After 40 days' therapy the values of TSH were 3.5 mcU/ml, TPO had a positivity of 1:300. Symptoms had disappeared and the gland appeared reduced in volume although the echographic imaging maintained distinguishing marks of autoimmune thyroid desease. Three months after the diagnosis TPO values had became normal again, TSH was of 1.5 mcU/ml. The thyroid was always palpable but at the echographic examination the tissue appeared more homogeneous and compact. The echo colour Doppler showed a reduction in the vascular flux. The therapy was suspended. At the moment the patient is in clinical echographic and laboratory follow-up: no signs of relapse.
Comment
Post Partum Thyroiditis is an autoimmune thyroid desease often underestimated. Its symptoms are not always evident because of its tendency to self limitation. Such form of thyroiditis has a recurrent course in pregnancy and it can sometimes look like hypothyroidism. Constant characteristic of this desease is the presence of antibodies, sometimes at a high title. This presence is not sufficient to diagnose a desease for it appears in 10% of healthy population. The presence of a high title of antibodies during pregnancy would favour the growth of autoimmune thyroiditis after pregnancy. PPT goes through two different phases. The first phase, which is brief and often not easily documented is characterised by proportionally elevated fT3 and fT4 values, with a low/unmeasurable TSH and with I131 reduced captation. The second one is often longer and more evident. It is characterised by normal/low values of thyroid hormones with elevated or hyper-responsive to TRH test TSH. Generally, this desease seems to be autolimitative with progressivel antibodies normalization. Normal hormonal functions and echo structural pattern are restored. Sometimes, especially after repeated pregnancies, PPT can be transformed into chronic thyroiditis with hypothyroidism. From a cytological point of view the picture is the same as lymphocitic thyroiditis except for the presence of plurinucleate giant cells. The presence of lymphocytes and debris gradually reduces. At last, when the gland dimention becomes normal again no cytological examination can be carried out and, in short, it appears to be of no use. On the contrary, the echographic examination, showing an increase in volume and diffuse hypoechogenicity is often diagnostic. It can be favourably used during the follow-up to identify a "restitutio ad integrum" of the parenchyma texture, which is correspondent to functional recovery "imaging".
References
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address your comments by e-mail to: radpa@cere03.cere.pa.cnr.it
University of Palermo, Institute of Radiology "P. Cignolini"
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