Hashimoto's thyroiditis
Hashimoto’s thyroiditis is an autoimmune disorder of the thyroid gland,
in which lymphocytic infiltration destroys the stromal architecture,
ultimately leading to symptoms and signs of hypothyroidism.
However,
in approximately 5-10% of cases,
patients can present with initial hyperthyroidism - "Hashitoxicosis".
Fig. 1: A portrait of Dr Hashimoto, a Japanese physician of Kyoto Imperial University
References: Hiromatsu Y et al. (2013) Hashimoto’s thyroiditis: History and future outlook. Hormones 12(1):12-18
This disease was first described by Dr.
Hakaru Hashimoto (Fig 1),
a Japanese physician of Kyoto Imperial University in 1912.
While examining the histology of thyroid tissue at the University,
he noticed a new pathological appearance of thyroid tissue in four middle aged women.
He named these findings “struma lymphomatosa”. [1]
The mainstay of diagnosis is with serum hormone levels and positive TPO antibodies.
In cases where these levels are borderline,
or not in keeping with clinical examination,
US can be used in the first instance to look for supporting evidence.
US evidence of Hashimoto's Thyroiditis:
- heterogeneous thyroid goitre
- "thyroid inferno" (Fig 2 and 3) in thyrotoxic phase
- hypoechoic micronodules
As an adjunct to this,
nuclear scintigraphy (Tc99m pertechnetate) can also be used (Fig 4).
Although not specific to Hashimoto's disease,
in the right clinical context this test can help confirm the diagnosis:
- absence of uptake in the neck
- increased relative salivary gland uptake
The main treatment of the resultant hypothyroidism includes thyroid replacement therapy and regular monitoring of thyroid function. In some cases surgical intervention may be considered.
For example,
compressive symptoms due to a large goitre e.g.
stridor and dysphagia,
concerning features on USS of a malignant nodule,
as well as cosmetic concerns from the patient.
Graves' disease
Graves' disease is an autoimmune disorder of the thyroid gland characterised by hyperthyroidism.
This is as a result of circulating autoantibodies that stimulate gland growth and the production of excess thyroid hormone.
Fig. 5: A portrait of Dr Graves an Irish physician working in Meath Hospital, Dublin.
References: RCSI Heritage Collection [available at: https://rcsiheritage.blogspot.com/2014/10/at-slumber-with-graves.html?view=flipcard]
Graves' disease was originally described by Dr.
Robert James Graves (Fig 4),
who was an Irish physician working in Meath Hospital,
Dublin. In 1835,
he described the presentation of three young female patients with symptoms and signs of hyperthyroidism associated with a goitre. He also described a fourth woman with exophthalmos.
[2]
Again,
the mainstay of diagnosis is with serum hormone levels and positive antibodies.
In the case of Grave's disease,
the most specific auto-antibodies are TRAb.
In cases where these levels are borderline,
or not in keeping with clinical examination,
US can be used in the first instance to look for supporting evidence.
US evidence of Graves' Disease:
- heterogeneous thyroid goitre
- "thyroid inferno" (Fig 2 and 3)
Nuclear scintigraphy (Tc99m pertechnetate) can also be used (Fig 6).
Although not specific to Graves' disease,
in the right clinical context this test can help confirm the diagnosis:
- increased of uptake in the neck
- decreased relative salivary gland uptake
Strict medical management to control symptoms is essential. Excess thyroxine produced is suppressed with either carbimazole or propythiouracil. Symptomatic control can also be aided with the use of beta-blockers.
Radioiodine may also be used to render the patient euthyroid and uncommonly surgical intervention is considered. Although surgical intervention has a high curative rate; the patient must be returned to a euthyroid state preoperatively. Surgical intervention in a hyperthyroid patient can be technically challenging and has a higher risk of morbidity and mortality,
with common complications being haemorrhage,
hypoparathyroidism and vocal cord paralysis.
Lemierre's syndrome.
Lemierre’s syndrome is the presence of thrombophlebitis of the internal jugular vein as a consequence of an ipsilateral infection to the oropharynx,
for example tonsillitis,
deep neck space infections and dental infections. It is usually caused by the bacteria Fusobacterium Necrophorum.
(3)
Fig. 7: Dr Andre Lemierre, a French microbiologist who published a case series of twenty patients with a history of an acute oropharyngeal infection and either clinical or radiological evidence of internal jugular vein thrombosis.
References: Wikipedia [available at: https://fr.wikipedia.org/wiki/Andr%C3%A9_Lemierre]
The condition was first described by Dr Andre Lemierre,
a French microbiologist in 1936 (Fig 7).
He published a case series of twenty patients who had had a history of an acute oropharyngeal infection and either clinical or radiological evidence of internal jugular vein thrombosis.
[3]
Radiologically,
chest X-ray may demonstrate cavitating lesions and US neck will demonstrate internal jugular vein thrombus.
However,
in patients with (neck) sepsis and worsening respiratory function,
urgent CT neck and thorax with contrast are advised,
due to speed and superior anatomical definition.
Findings include:
- Intraluminal filling defect in the internal jugular vein (Fig 8)
- Signs of thrombophlebitis - enhancement of the vasa vasorum (Fig 9)
- Possible underlying cause e.g.
tonsilar abscess,
retropharyngeal abscess
- Septic emboli - Multiple cavitating lung nodules (Fig 10 and 11)
Because of the widespread introduction of antibiotics,
the incidence of Lemierre’s syndrome has plummeted.
However,
with the rise in antibiotic resistance,
its prevalence is slowly rising again.
The mainstay of treatment remains optimisation of medical management with regular consultation with microbiology to ensure adequate antibiotic cover.
It is important to identify any collection which would be amenable to surgical drainage. Anticoagulation and/or ligation of the internal jugular vein is not part of routine management and is only used in severe cases not responding to surgical drainage and antibiotic cover [3].
Wermer (MEN1)
Multiple endocrine neoplasia type 1 (MEN-1) is a tumour syndrome comprising of parathyroid tumours,
pancreatic islet cell tumours and anterior pituitary tumours.
The condition is autosomal dominant,
however mutations can occur sporadically.
Although there had been cases reported of multiple endocrine neoplasms by Erdheim in 1903,
and Cushing and Davidhoff two decades later; it is the work of Paul Wermer (Fig 12),
who described the MEN-1 phenotype,
which led to this condition being designated his name.
[4] He described an autosomal dominant inheritance of the syndrome after observing a family in which the father and four of his nine children were affected.
[5]
Fig. 12: In 1954, Paul Wermer, described the MEN-1 phenotype
References: Wellbourn RB (1990) The history of endocrine surgery. Westport: Praeger
Parathyroid
Imaging is usually undertaken in the presence of hyperparathyroidism and begins with US (Fig 13).
Findings include:
- enlarged (single or multiple) parathyroid adenomas
- adenomas are often well circumscribed and hypoechogenic compared to the thyroid gland
- feeding vessel (from the inferior thyroid artery)
Note however that adenomas can be difficult to distinguish from lymph nodes and can be intra-thyroid in location.
In order to confirm the presence of a functioning adenoma pre-operatively,
Sestamibi-SPECT/CT can be used (Fig 14).
Findings include:
- Retained tracer uptake on delayed planar imaging
- Soft tissue nodule on CT component
- If IV contrast given,
nodule is hypo-echoic compared to the thyroid gland
Pituitary
MRI pituitary is the mainstay of imaging and can be performed in the presence of clinical syndrome e.g.
Cushing's or biochemical abnormality.
Findings include:
- micro and macro adenomas
- adenomas can be iso/hypo intense on T1 and no not enhance as avidly as the background pituitary (Fig 15)
Pancreatic islet cell tumours
Tumours can be benign or malignant and vary histologically.
Insulinomas,
gastrinomas and mucinous tumours have been documented.
CT or MRI liver (Fig 16) with functional SPECT imaging (Fig 17) are helpful at localising tumours and metastases.
Due to the diversity in presentation of these patients,
genetic diagnosis and regular monitoring is essential. The clinician must be aware of the different tumours that can be present and use biochemical markers and radiology to help in the diagnosis and management of these tumours.
Gradenigo's syndrome
Gradenigo’s syndrome is a complication of otitis media. It is described as a triad of symptoms: purulent otorrhoea,
ipsilateral facial pain (due to Trigeminal nerve involvement) and ipsilateral Abducens nerve palsy causing diplopia.
[6] This is as a result of extension of infection from the middle ear into the petrous apex of the temporal bone (also known as petrous apicitis).
Giuseppe Gradenigo (Fig 18),
born in Venice in 1859,
is to this day one of the most well-known pioneers of Otology.
[7] In 1904,
Dr.
Gradenigo presented a series of cases of Abducens nerve paralysis,
which was thought to have an otological aetiology. This would later be known as Gradenigo’s syndrome.
Fig. 18: Giuseppe Gradenigo, born in Venice in 1859, is to this day one of the most well-known pioneers of Otology.
References: Felisati D and Sperati G. (2009) Gradenigo's syndrome and Dorello's canal. Acta Otorhinolaryngol Ital 29:169-172
In the acute setting,
clinicians will want to exclude mastoiditis and petrous apicitis.
It is reasonable therefore to use CT as a first line modality to assess the temporal bones.
CT findings include (Fig 19):
- Hyperpneumatisation of the mastoid air cells
- Middle ear effusion
- Mastoid air cell effusion
- Bony destruction.
MR of the skull base can then be used to compliment CT in order to assess the petrous apex,
the skull base canals and formamina and cranial nerve involvement.
MR findings include (Fig 20 and 21):
- Middle ear effusion
- Loss of normal bone marrow signal in the petrous temporal bone
- Soft tissue enhancement +/- abscess
Aggressive antibiotic therapy is imperative in the treatment of this pathology. In cases where antibiotic therapy does not demonstrate significant improvement,
a mastoidectomy or petrousectomy may be indicated in order to remove any granulation or necrotic debris. Surgical intervention also allows purulant secretions to be removed and the cavity to be adequately irrigated.