Differential Diagnosis Case Study Example

Question A: contrast between the altered physiological changes seen with the normal thyroid physiology

The normal thyroid physiology is indicated by certain biomarkers. In this case, the serum level of hormones free triiodothyronine (T3) and thyroxine (T4) indicates whether the thyroid gland is normally functional or not. According to the result of the lab test carried on the patient, a significant deviation of the serum levels of thyroid hormones from the normal level has been noted.
First, the free T4 level of the patient was found to be 5.4 picomoles per litre (pmol/L). The reference range of T4 is 9-25 picomoles per litre (Vanderpump, Tunbridge, and Bayliss, 2008). The reference values represent the values that most healthy individuals would exhibit. The reference range of free T4 level varies from one laboratory to another (Brunner, 2010). However, most laboratories indicate that it should not exceed 12pmol/L. For instance, according to Carroll (2010), the normal range of serum free T4 is 4.5-11.2pmol/L. On the other hand, Karmisholt, Andersen,, and Laurberg (2010) identify the reference range to be from 12 to 22pmol/L. The patient’s T4 level is lower than the normal range. This reveals that the patient’s thyroid physiology is altered. Low T4 level combined with high thyroid-stimulating hormones level (TSH) is associated with hypothyroidism. Free T4 level is a more reliable indicator of the thyroid functioning than the total T4. An explanation for this fact is that the level of total T4 is dependent on the amount of thyroxine that is bound to the transport protein (Vanderpump, Tunbridge, and Bayliss, 2008). Consequently, the test for the total serum T4 may not be accurate for an individual with an abnormal level of transport protein.
The patient has also been found to be having elevated level of TSH. At 37mlU/L, the patient’s TSH level is above the reference range. Even though the reference range of TSH varies from one laboratory to another, most laboratories agree that TSH level for a normal person should range from 0.5 to 5.5 milliunits per litre. For instance, according to Karmisholt, Andersen, and Laurberg (2010), normal TSH values range from 0.27 to 4.2Miu/L. The TSH level observed in the patient, coupled with low free T4 level indicates that the patient is likely to be suffering from hypothyroidism. Hypothyroidism is characterised by reduced secretion of thyroid hormones. Pituitary gland usually responds to the low level of thyroid hormones by secreting more TSH in order to increase the activity of the thyroid thus explaining the high level of TSH observed in the patient. The increase in the level of TSH is proportionate to the decrease in the levels of both free triiodothyronine and thyroxine hormones (Vanderpump, Tunbridge, and Bayliss, 2008).
The thyroid peroxidase antibody test also turned positive. In this case, the results showed that the level of thyroid peroxidase antibodies is more than 600kU/L. The reference level ranges from 5 – 34 kU/L. Therefore, the level of thyroid peroxidase antibodies tested in the patient is far much above the reference level. Thyroid peroxidase is an enzyme mainly found in the thyroid gland. The enzyme plays an important role in the production of thyroid hormones. Thyroid peroxidase antibodies act against the hormones. Consequently, their presence in the blood signifies autoimmune response. Thus, thyroid peroxidase antibody test is used to determine whether the cause of the malfunctioning of thyroid disorder is an autoimmune disorder or not. Given that the patient has tested positive for thyroid peroxidase antibody, her thyroid disease must have been caused by an autoimmune disorder. In other words, the diagnosis for the patient is Hashimoto’s hypothyroidism.
In general, the test results discussed above indicate that the patient’s thyroid physiology is altered. The low level of serum free T4 coupled with the elevated levels of TSH and thyroid peroxidase antibodies clearly diagnose hypothyroidism. In hypothyroidism, thyroid gland secrets low level of thyroid T4 and T3. As a result, the pituitary gland responds by secreting more TSH. TSH boosts the functioning of the thyroid gland by stimulating follicular cells pinocytose colloid to release thyroglobulin. Thyroglobulin plays an important role in the release of active T4 and T3 into the bloodstream.

The patient presented with a small, asymptomatic thyroid swelling. Her blood analysis revealed that she had an elevated level of TSH and thyroid peroxidase antibodies. In addition, the test revealed low level of T4. Thyroid swelling is usually associated with goitre, thyroid carcinoma, Graves’ disease, and thyroiditis. On the other hand, low level of serum thyroid hormones, T4 and T3, is associated with a disorder of the thyroid gland that leads to low secretion of thyroid hormones.
Based on the asymptomatic swelling of the thyroid of the patient, a number of causes can be suspected. For instance, goitre, Graves’ disease, and thyroiditis are some of the common causes of the enlargement of the thyroid gland (Henderson, 2009). However, this symptom alone is not sufficient to diagnose the problem that the patient is suffering from. However, the patient does not exhibit other signs and symptoms of Grave’s disease. In addition, among people with Grave’s disease, the level of thyroid-stimulating hormone is lower than normal. Such people also tend to have higher than normal levels of thyroid hormones. However, since the test on the patient in this case study showed a higher than normal level of TSH and lower than normal level of thyroid hormones, Graves’ disease is ruled out. Diagnosis of the Graves’ disease would have been possible if the patient had recorded higher than normal level of thyroid hormones and lower than normal level of TSH. Both goitre and thyroiditis are associated with elevated levels of TSM coupled with low level of thyroid hormones. Since the blood tests conducted on the patient in this case study show that the patient has elevated levels of TSH and lower than normal levels of thyroid hormones, the patient is likely to be suffering from thyroiditis. Thyroid carcinoma is not likely to be suspected in the patient since the blood test results reported by the patient show lower than normal levels of thyroid hormones. On the other hand, patients with thyroid carcinoma usually show normal levels of thyroid hormones. However, thyroid carcinoma also presents with normal levels of TSH unlike other conditions of the thyroid gland. Diagnosis of thyroid carcinoma does not rely entirely on the blood test. Instead, other means of diagnosis such as biopsy, ultrasound, imaging tests, chest X-ray, radioiodine scan, Magnetic resonance imaging (MRI) scan, and computed tomography scan should be conducted.
Based on the symptom presented by the patient and the blood test results obtained, the most likely diagnosis is underactive thyroid gland. The underactive thyroid gland can be attributed to various aetiologies. Some of the possible causes of the condition are the following: autoimmune disorder, thyroid surgery, medications, radiation therapy, and treatment of hyperthyroidism, congenital disease, pregnancy, iodine deficiency, pituitary disorder, and thyroid surgery. The patient has not reported history of hyperthyroidism or the use of any medication that might result in the interference with the physiology of the thyroid gland. In addition, the patient is 78 years old. Consequently, she is past menopause, hence, cannot get pregnant. There is no history of thyroid surgery either. Therefore, most of the possible causes mentioned above are not likely to be the case with the patient in the case study. However, thyroid peroxidase antibody test reveal a high level of thyroid peroxidase antibodies. This confirms that the underactive thyroid gland is attributed to the autoimmune disease. Thyroid peroxidase antibody tends to act against the thyroid peroxidase enzyme. These enzymes are found in the thyroid gland, and they help in the synthesis and secretion of thyroid hormones. High serum level of the antibodies indicates a high level of inhibition of the thyroid gland from functioning properly.

Complications That Could Occur If The Swelling Increased In Size

Progression of hypothyroidism is associated with serious complications. Consequently, it is important to take early precautions in order to avoid health risks associated with these complications. Such complications include the following: birth defects, goitre, myxoedema, infertility, heart problems, mental health problems, and others (Vanderpump, Tunbridge, and Bayliss, 2008). For the patient in our case study, the complications discussed below might occur if the swelling increases in size:
First, the patient is likely to develop heart problems in the long run if the thyroid swelling continues to enlarge. In this case, underactive thyroid gland leads to an increase in the level of bad cholesterol. Continued increase in the level of bad cholesterol may result in the hardening of arteries, atherosclerosis, and even thrombosis. Hardening or arteries can lead to hypertension and other heart problems. It can also lead to an increase in the risk of heart attack and stroke. As a result of hypothyroidism, pericardial effusion (fluid build-up around the heart) may result (Hotze, 2013). Consequently, it may be harder for the heart to pump blood throughout the body. As a result, various body cells, especially those at the periphery may fail to get adequate oxygen. Eventually, conditions such as stroke and heart attack may result.
Secondly, progression of hypothyroidism can result in serious mental problems (Camacho, 2011). For instance, it can cause mild forms of depression. The severity of depression may increase if no treatment is given in time. Other symptoms of hypothyroidism may increase and continue impacting on the already poor mental state. Studies have also reported that when hypothyroidism is not treated, it may continue to cause deterioration in mental functioning. It is important to note that the poor health status attributed to the progression of untreated hypothyroidism also partly further impact on the poor mental state.
Another serious possible complication that may arise as a result of the progression of hypothyroidism is myxoedema (Gourin and Pitman, 2007). This condition is severe and might result in the loss of life if timely and appropriate action is not taken to control the symptoms of hypothyroidism. In this case, the continued enlargement of the thyroid gland may lead to deterioration of the rate of metabolism to the extent that one might fall into a coma at times. Symptoms of myxoedema include intolerance to cold and severe fatigue. Myxoedema mainly occurs after hypothyroidism has progressed for a long time. It is advisable to seek medical attention in a timely manner in order to avoid this complication. However, the condition hardly progresses to the level of myxoedema since it is rare to fail to recognise the symptoms of the condition in a timely manner.
Failure to treat hypothyroidism in time may also result in goitre. Goitre is a condition characterised by an excessive enlargement of the thyroid gland to an extent that one has a huge swelling in one’s neck. The enlargement results from an excessive stimulation of the thyroid gland in a bid to produce enough thyroid hormones.
In general, the complications associated with a failure to treat hypothyroidism are serious and should not be ignored. One needs to visit a doctor upon identifying any sign or symptom of thyroid dysfunction. Timely and appropriate treatment may help prevent complications associated with the condition. It should also be noted that conditions affecting the thyroid gland are quite serious especially owing to the fact that the thyroid hormone influence the rates of all the metabolic activities in the body.
What other investigations could you carry out to confirm your diagnosis? Describe three of them and give reasons for your choice
Other investigations that I would carry out are the following: nutrition assessment, patient history, and Thyroid ultrasound of the patient. In the nutrition assessment, I would conduct a 24-hour recall in order to determine the patient’s level of consumption of iodine. Besides, I would ask the patient to keep a one-week food diary to help check the nutritional habits of the patient in order to determine whether the patient consumes an adequate amount of iodine. This investigation would help in determining whether the patient’s condition is attributed to iodine deficiency. Medication history would help determine if the patient had once used any medication with the side effects that interfere with the functioning of the thyroid gland. In addition, patient history helps investigate whether the patient has congenital thyroiditis.
A 24-hour recall is a questionnaire with items that seek to determine one’s energy and nutrient intake. It helps in determining whether the ordinary dietary behaviour of a patient is adequate. The patient is meant to address all the items in the questionnaire in order to determine the scores in the tool. High scores indicate that one’s diet is adequate in the nutrients being investigated. On the other hand, patient history involves gathering of data concerning the patient’s previous medications, family history, and health history. Based on patient history, it is possible to determine whether the present condition is due to previous treatment of hyperthyroidism, side effects of certain medications or congenital condition.
Ultrasound of the thyroid uses ultrasound gel and small transducer to produce the picture of the thyroid gland. It produces a picture of the thyroid gland and the structures adjacent to it. This method is non-invasive. However, it may be uncomfortable at times. Ultrasound of the thyroid is not usually necessary in diagnosing Hashimoto’s thyroiditis. However, the method is instrumental in assessing the size of the thyroid gland. In addition, it helps in investigating the presence of thyroid nodules and echo texture. These other investigations would help in the diagnosis of the patient’s condition.

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