Case summary An 8-year-old, male neutered domestic shorthair cat was presented with acute onset of ataxia, apathy, hypersalivation and anorexia. Clinical examination revealed a swollen, bluish tongue tip, neurological deficits, hypothermia, hypotension and a left-sided systolic heart murmur with arrhythmia. Blood pressure was initially low but normalised after dobutamine therapy. Thoracic radiographs revealed cardiomegaly, and echocardiography confirmed a hypertrophic cardiomyopathy (HCM) phenotype with severe left atrial dilation, spontaneous echo contrast and suspected thrombus formation. MRI of the head showed absent contrast enhancement in the rostral two-thirds of the tongue and signal changes consistent with lingual infarction. Doppler ultrasound confirmed absent blood flow in the affected tongue region. Based on imaging, cardiac findings and clinical signs, a lingual artery thromboembolism was considered the most likely diagnosis. The patient was treated with anticoagulant therapy and supportive care, but because of worsening tongue swelling, functional impairment and underlying advanced heart disease, euthanasia was elected. Relevance and novel information To the authors' knowledge, this case represents the first reported case of feline arterial thromboembolism affecting the lingual artery. Although HCM was the presumed cause, other thromboembolic risk factors, such as hyperthyroidism, could not be definitively excluded. This case emphasises the need to consider atypical thromboembolic presentations in cats with cardiac disease and highlights the diagnostic value of advanced imaging modalities in identifying uncommon sites of arterial obstruction.

The thyroid gland is an essential endocrine organ that secretes hormones to regulate homeostasis across multiple organ systems throughout the body. It is actively regulated by the hypothalamic-pituitary-thyroid (HPT) axis, where negative feedback modulates the amounts of active hormone being released; thus, lesions that disrupt the proper functioning of this gland or its regulatory mechanisms can be destructive. Toxic thyroid adenomas are usually singular benign functioning nodules in the thyroid gland that cause thyrotoxicosis. Hyperthyroidism is commonly clinically silent, however, in most symptomatic cases, patients will be diagnosed based on abnormal laboratory findings and typical hyperthyroid symptoms. This case report examines an 81-year-old male with an extensive medical history who presented with complaints of new-onset generalized fatigue coupled with bilateral lower extremity muscle cramps. A positron emission tomography (PET) scan for other medical conditions incidentally noted mildly increased uptake in the thyroid gland, prompting a further investigation that resulted in a diagnosis of toxic thyroid adenoma. The patient responded well to treatment with methimazole and has remained in a euthyroid state.

Incidence of thyroid dysfunctions including hypo- or hyperthyroidism is significantly increased. Hyperthyroidism is common in males, and hypothyroidism is often seen in females. Here, we report two female patients suffering from hyperthyroidism, but their signs and symptoms are totally opposite to each other.

The relationship between psychiatric symptoms and thyroid function has been well known and studied since antiquity. The common view is that clinical hypothyroidism is associated with depressive symptoms, whereas the psychiatric manifestations of hyperthyroidism are agitation, emotional lability, hyperexcitability, occasionally accompanied by angry outbursts, and euphoria. The case here reported overturns this conventional medical knowledge. A 73-year-old Italian woman experienced a severe major depressive episode with psychotic and melancholic features during laboratory thyrotoxicosis. No classical clinical signs and symptoms of thyrotoxicosis were present. Psychiatric symptoms improved together with the resolution of the hyperthyroid state. Historically, different cases of so-called 'apathetic hyperthyroidism' have been described. Recent neuroimaging and animal studies provided possible neurobiological explanations, showing how the excess thyroid hormones could affect brain structures involved in the regulation of mood, leading to depression. A direct link between hyperthyroidism and depression seems to be likely. This insight may be relevant in facilitating early diagnosis of thyroid disease and the planning of therapeutic strategies.

Hyperthyroidism in the elderly population is often associated with atypical, blunted, or nonspecific signs and symptoms, also known as apathetic hyperthyroidism (AH). The absence of the classical hyperkinetic clinical presentation can be confused with the normal aging process, or other diseases, and often leads to misdiagnosis, delayed treatment, and negative outcomes for elderly patients. We provide a case study of an elderly patient to illustrate the atypical presentation of AH. The vignette also highlights a diagnostic and treatment approach based on geriatric medicine fundamentals and evidence-based research. We then review the multiple factors and pathogenetic mechanisms contributing to endocrine disruptors and the paucity of hyperadrenergic signs and symptoms in the elderly with hyperthyroidism. Additionally, the article contrasts the symptomatology and diagnostic profile between primary hyperthyroidism and AH. Finally, we provide an evidence-based, patient-centered approach to manage AH in the elderly population. We recommend that nurse practitioners cultivate illness script inclusive of atypical presentations to guide their clinical decision making. Psychomotor retardation with or without cardiovascular symptoms warrant a high degree of suspicion and the initiation of laboratory studies, including thyroid functions to confirm or rule out hyperthyroidism.

Thyroid hormones (TH) have a cardinal role in the development of the central nervous system during embryogenesis and early infancy. However, the TH-responsive genes in the developing brain cease to respond to TH in adulthood. Nevertheless, thyroid dysfunction in adults is commonly associated with a host of cognitive and psychiatric problems. Cognitive decline, dysphoria, and depression are common manifestations of overt hypothyroidism while hyperthyroidism can cause agitation, acute psychosis, and apathy, especially in older people. Whereas levothyroxine treatment can reverse dementia in the setting of hypothyroidism, the effect of levothyroxine on depressive symptoms in subjects with subclinical hypothyroidism is controversial. The use of supraphysiologic doses of TH to treat depression refractory to antidepressant remains a viable therapeutic tool with the caveat that excessive doses of thyroid hormone to treat depression may have potentially damaging effects on other organ systems. The present communication describes the pathophysiology of neuropsychiatric manifestations of thyroid disease, including changes in neurotransmission, alterations in neuronal or glial cell gene expression, blood-brain barrier dysfunction, increased risk of cerebrovascular disease, and occasionally cerebral inflammatory disease in the context of autoimmune thyroid disease. Elucidating the molecular mechanisms of TH effect on cerebral tissue will help identify novel therapeutic targets for managing people with neuropsychiatric disorders.

Atrial fibrillation as an initial presenting symptom of an apathetic thyroid storm is under-reported, especially in the setting of undiagnosed hyperthyroidism. Very rarely, thyroid storm can present with apathetic symptoms. The author presents a case of apathetic thyrotoxicosis with atrial fibrillation. The patient had a generalized weakness, lethargy, and weight loss as initial symptoms and was found to have atrial fibrillation, which was initially thought to be the inciting event. However, further evaluation revealed a new diagnosis of apathetic thyroid storm secondary to uncontrolled Graves' disease. She was managed medically for thyroid storm with hopes to control the tachyarrhythmia by controlling the underlying etiology. Subsequently, her symptoms resolved, and she came back to baseline except for continued atrial fibrillation, which was rate controlled. Early recognition of an apathetic thyroid storm can prevent mortality and morbidity as it can often be missed due to atypical symptoms.

Anti-N-methyl-D-aspartic acid-receptor (NMDA-R) encephalitis is a novel disease discovered within the past 10 years. It is an autoimmune disease (AD) that has been associated with other ADs, such as Graves' disease. However, association with autoimmune polyglandular syndromes (APS) has not been previously described. A 58-year-old woman presented with altered mental status and an 8-month history of weight loss, apathy and somnolence. Laboratory evaluation confirmed Graves' disease with thyrotoxicosis and type 1 diabetes mellitus. Despite treatment, she continued to have a fluctuating mental status. Further diagnostic evaluation included an abdominal MRI that showed a cystic lobular left adnexal mass. Serum anti-NMDA-R antibodies were positive, raising concern for NMDA-R encephalitis. Bilateral salpingo-oophorectomy was performed, with pathology consistent with cystadenofibroma. She had a favourable recovery with marked clinical improvement. Anti-NMDA-R antibodies were negative 2 months following surgery. The concomitant occurrence of APS and anti-NMDA-R encephalitis suggests a shared mechanism of autoimmune pathophysiology.

We report a case of apathetic hyperthyroidism associated with unrecognized slowly growing functional thyroid adenoma (Plummer's disease), atrial fibrillation and heart failure. An 81-year-old woman with worsening thyroid dysfunction was admitted to our hospital for the treatment of heart failure. The patient had developed heart failure associated with chronic atrial fibrillation at 76 years of age, and one year later was found to have asymptomatic hyperthyroidism. Anti-thyroid autoantibodies were negative, but thyroid echography showed a 32-mm tumor devoid of internal blood flow in the left lower lobe. Free thyroxine 4 (FT4) decreased from 3.30 to 2.60 ng/dl without treatment. The patient was diagnosed with transient thyroiditis and was followed-up without treatment. However, a repeat thyroid echography showed growth of the tumor to 41 mm in 4 years. Thyroid scintigraphy showed uptake that matched the thyroid mass. Based on these findings, the established diagnosis was Plummer's disease complicated with heart failure. The patient was treated with anti-thyroid drugs, which resulted in improvement of FT4 and reduced the severity of heart failure. In this rare case of an elderly patient, Plummer's disease was associated with a slowly-growing functional thyroid adenoma, apathetic hyperthyroidism, repeated episodes of atrial fibrillation and heart failure. Since symptoms of thyrotoxicosis are likely to be missed in the elderly, it is necessary to include hyperthyroidism in the pathoetiology of heart failure and atrial fibrillation in this population.

Apathetic form of thyrotoxicosis occurs in the elderly who can present with features of hyperglycemia, hypothyroidism, depression, or an internal malignancy. A clinical suspicion and timely diagnosis of hyperthyroidism is needed to define the correct etiology of existing problems, and to prevent grave complications. We discuss an 84-year-old woman who presented with fatigue and uncontrolled diabetes due to apathetic thyrotoxicosis.

Thyroid storm is a complication of thyrotoxicosis with a 20% to 30% mortality rate characterized by hyperthermia, tachycardia and altered mental status. Rarely, thyroid storm may have an apathetic presentation. The authors present a 63-year-old woman with apathetic thyrotoxicosis and hypercalcemia. The action of thyroid hormones stimulating bone resorption more than bone formation is thought to cause increased bone demineralization and, occasionally, hypercalcemia. This occurs in the absence of malignancy, prolonged immobility, hypervitaminosis D and primary hyperparathyroidism. Her thyroid storm was medically managed and her hypercalcemia was treated with intravenous fluids, calcitonin and a bisphosphonate. This case describes the presence of hypercalcemia in a patient with apathetic thyroid storm with no other factors contributing to the hypercalcemia. In addition, this patient had significant elevation in serum calcium, which possibly contributed to her symptomatology. The calcium remained normal after the thyrotoxicosis resolved, which is typical of the hypercalcemia of thyrotoxicosis.

Thyrotoxic patients may occasionally present with affective disorders. Here, we discuss a case of a 61-year-old woman with misidentification and persecutory delusions, olfactory hallucinations, and apathy associated with thyrotoxicosis. After definitive antithyroid and antipsychotic agent haloperidol treatments, the patient was released within 4 weeks. Thyrotoxic psychosis with apathy is a rare entity that can be misdiagnosed as affective psychosis. Haloperidol may be an alternative treatment in resolving psychotic features beside the treatment of hyperthyroid state.

We present the case of a person with baseline Bipolar Affective Disorder, who starts receiving medical treatment for subclinical Hypothyroidism, during this time the patient develops Hyperthyroidism. During the course of the latter, the patient started to exhibit depressed mood symptoms and worsening of her baseline disorder. Typically there are depressive symptoms in hypothyroidism and manic symptoms in hyperthyroidism, there have been a few cases of depressive symptoms (depressed mood, asthenia and apathy) reported in patients with hyperthyroidism. Up till now it's a fact that Hyperthyroidism constitutes itself as a risk factor for developing or precipitating depressive states, thus increasing hospital readmissions, and another important fact is that of manifesting or worsening affective symptoms due to the influence of thyroid hormones. We also present the well-known relationship between thyroid malfunction and affective disorders.