Hypocalcaemia: Symptoms and Signs

Hypocalcaemia is a condition characterized by low levels of calcium in the blood. Since calcium is essential for proper muscle and nerve function, many of the symptoms and signs of hypocalcaemia are related to neuromuscular excitability. The most common features of hypocalcaemia include muscle twitching, cramping, and spasms, as well as perioral paraesthesia. In chronic cases, patients may experience depression and cataracts.

An electrocardiogram (ECG) may show a prolonged QT interval, while Trousseau’s sign may be present when the brachial artery is occluded by inflating the blood pressure cuff and maintaining pressure above systolic. This causes wrist flexion and fingers to be drawn together, and is seen in around 95% of patients with hypocalcaemia and around 1% of normocalcaemic people. Chvostek’s sign, which is seen in around 70% of patients with hypocalcaemia and around 10% of normocalcaemic people, involves tapping over the parotid gland to cause facial muscles to twitch.

In summary, hypocalcaemia can cause a range of symptoms and signs related to neuromuscular excitability, including muscle twitching, cramping, and spasms, as well as perioral paraesthesia, depression, and cataracts. Trousseau’s sign and Chvostek’s sign are also commonly observed in patients with hypocalcaemia.

Differentiating Causes of Thyrotoxicosis: A Brief Overview

Thyrotoxicosis, or hyperthyroidism, can be caused by various conditions, including Graves’ disease, De Quervain’s thyroiditis, Hashimoto’s thyroiditis, hypothyroidism, and toxic multinodular goitre. Among these, Graves’ disease is the most common cause, characterized by autoimmune dysfunction and typical hyperthyroid symptoms. About a third of patients with Graves’ disease also develop eye signs, while pretibial myxoedema or clubbing of the fingers may occur rarely. De Quervain’s thyroiditis, on the other hand, is associated with transient hyperthyroidism following a viral infection and neck pain. Hashimoto’s thyroiditis, an autoimmune condition, causes hypothyroidism instead of hyperthyroidism. Hypothyroidism presents with weight gain, fatigue, constipation, dry skin, and depression, and is characterized by raised TSH and reduced T4 or T3. Finally, toxic multinodular goitre is the second most common cause of hyperthyroidism in the UK, presenting with a multinodular goitre and hyperthyroidism without Graves’ disease symptoms. However, in the case presented, the positive TPO antibodies and typical Graves’ disease symptoms make it the most likely diagnosis.

When a patient is scheduled for surgery, it can be confusing to know how to manage their medications. However, it is important for junior doctors to be knowledgeable in this area. Time-critical medications, such as those used for Parkinson’s disease, epilepsy, and diabetes, should be taken up to two hours before surgery with clear fluids. For patients taking metformin, the medication should be continued as normal if taken once or twice daily. If taken three times daily, the lunchtime dose should be skipped. This is because metformin can increase the risk of acute kidney injury if a meal is missed during surgery. If the patient’s eGFR falls below 60, metformin should be avoided for 48 hours after surgery. If the patient has poor diabetes control or a longer surgery, variable rate intravenous insulin infusion may be used. All other medications used for type two diabetes should be stopped.

Preparation for surgery varies depending on whether the patient is undergoing an elective or emergency procedure. For elective cases, it is important to address any medical issues beforehand through a pre-admission clinic. Blood tests, urine analysis, and other diagnostic tests may be necessary depending on the proposed procedure and patient fitness. Risk factors for deep vein thrombosis should also be assessed, and a plan for thromboprophylaxis formulated. Patients are advised to fast from non-clear liquids and food for at least 6 hours before surgery, and those with diabetes require special management to avoid potential complications. Emergency cases require stabilization and resuscitation as needed, and antibiotics may be necessary. Special preparation may also be required for certain procedures, such as vocal cord checks for thyroid surgery or bowel preparation for colorectal cases.

The patient is suffering from Cushing’s syndrome, which is characterized by an excess of cortisol. This can be caused by exogenous glucocorticoid therapy, autonomous overproduction by the adrenal glands, or increased production of adrenocorticotrophic hormone. High levels of cortisol can mimic the effects of aldosterone, leading to increased sodium and water retention and increased potassium excretion, resulting in hypokalemia. The increased resorption of bicarbonate in the tubules due to potassium depletion causes metabolic alkalosis. Hyperkalemic metabolic acidosis is not expected because cortisol’s effect on the mineralocorticoid receptor causes a loss of potassium. Hyperkalemic respiratory alkalosis is also not expected because cortisol’s effect on the mineralocorticoid receptor leads to potassium excretion. Additionally, any acid-base disturbance in Cushing’s syndrome is likely to be metabolically mediated rather than respiratory. Hypokalemic metabolic acidosis is not expected because the concomitant loss of potassium and reabsorption of bicarbonate causes metabolic alkalosis.

Investigations for Cushing’s Syndrome

Cushing’s syndrome is a condition caused by excessive cortisol production in the body. There are various causes of Cushing’s syndrome, including iatrogenic, ACTH-dependent, and ACTH-independent causes. To diagnose Cushing’s syndrome, doctors typically perform tests to confirm the condition and determine its underlying cause.

General lab findings consistent with Cushing’s syndrome include hypokalaemic metabolic alkalosis and impaired glucose tolerance. Ectopic ACTH secretion, which is often associated with small cell lung cancer, is characterized by very low potassium levels.

The two most commonly used tests to confirm Cushing’s syndrome are the overnight dexamethasone suppression test and the 24-hour urinary free cortisol test. The overnight dexamethasone suppression test is the most sensitive test and is used first-line to test for Cushing’s syndrome. Patients with Cushing’s syndrome do not have their morning cortisol spike suppressed. The 24-hour urinary free cortisol test measures the amount of cortisol in the urine over a 24-hour period.

To localize the cause of Cushing’s syndrome, doctors may perform additional tests such as high-dose dexamethasone suppression test, CRH stimulation, and petrosal sinus sampling of ACTH. An insulin stress test may also be used to differentiate between true Cushing’s and pseudo-Cushing’s. Overall, a combination of these tests can help diagnose Cushing’s syndrome and determine its underlying cause.

The guidelines of NICE have been revised, stating that women who are at risk of gestational diabetes should undergo an oral glucose tolerance test immediately after booking, instead of waiting until 16-18 weeks as previously recommended.

Gestational diabetes is a common medical disorder affecting around 4% of pregnancies. Risk factors include a high BMI, previous gestational diabetes, and family history of diabetes. Screening is done through an oral glucose tolerance test, and diagnostic thresholds have recently been updated. Management includes self-monitoring of blood glucose, diet and exercise advice, and medication if necessary. For pre-existing diabetes, weight loss and insulin are recommended, and tight glycemic control is important. Targets for self-monitoring include fasting glucose of 5.3 mmol/l and 1-2 hour post-meal glucose levels.

Carcinoid tumors can lead to an increase in urinary 5-HIAA due to the release of serotonin. Symptoms of carcinoid syndrome include flushing, diarrhea, bronchospasm, hypotension, and weight loss. The appropriate diagnostic test for this condition is a urinary 5-HIAA test. CA125 is not relevant in this case as it is used to detect ovarian cancer. MRCP is used to investigate gallbladder or pancreatic conditions, while urinary metanephrines are used to diagnose phaeochromocytoma.

Carcinoid Tumours and Syndrome

Carcinoid tumours are a type of neuroendocrine tumour that can secrete various hormones and bioactive substances, including serotonin. When these tumours metastasize to the liver, they can release serotonin into the systemic circulation, leading to a condition known as carcinoid syndrome. This syndrome can also occur with lung carcinoids, as the mediators are not cleared by the liver.

The earliest symptom of carcinoid syndrome is often flushing, followed by diarrhoea, bronchospasm, hypotension, and right heart valvular stenosis. In bronchial carcinoids, the left heart can also be affected. In some cases, other molecules such as ACTH and GHRH may be secreted, resulting in conditions like Cushing’s syndrome. Pellagra, a condition caused by a deficiency of niacin, can also develop as dietary tryptophan is diverted to serotonin by the tumour.

To diagnose carcinoid syndrome, doctors may perform a urinary 5-HIAA test or measure plasma chromogranin A levels. Treatment typically involves somatostatin analogues like octreotide to manage symptoms, while cyproheptadine may help with diarrhoea. Proper management of carcinoid tumours and syndrome is crucial to prevent complications and improve quality of life for patients.

The most probable diagnosis in this case is primary hyperparathyroidism, which is caused by parathyroid adenoma or hyperplasia. The typical biochemical markers are low phosphate and high serum calcium levels. However, the parathyroid hormone level may be high or inappropriately normal. On the other hand, secondary hyperparathyroidism is caused by chronic hypocalcemia, such as in chronic kidney disease, where serum calcium levels are low or normal, but parathyroid hormone levels are high. Tertiary hyperparathyroidism is a result of autonomous parathyroid production and usually occurs in patients with end-stage renal disease. Sarcoidosis and type 1 renal tubular acidosis are rare causes of hypercalcemia.

Understanding Primary Hyperparathyroidism

Primary hyperparathyroidism is a condition commonly seen in elderly females, characterized by an unquenchable thirst and an inappropriately normal or raised parathyroid hormone level. It is usually caused by a solitary adenoma, with hyperplasia, multiple adenoma, and carcinoma being less common causes. While around 80% of patients are asymptomatic, those who do experience symptoms may have polydipsia, polyuria, depression, anorexia, nausea, constipation, peptic ulceration, pancreatitis, bone pain/fracture, renal stones, and hypertension. Primary hyperparathyroidism is also associated with multiple endocrine neoplasia (MEN I and II).

To diagnose primary hyperparathyroidism, doctors may look for raised calcium levels and low phosphate levels, as well as perform a technetium-MIBI subtraction scan. A characteristic X-ray finding of hyperparathyroidism is the pepperpot skull. Treatment options include total parathyroidectomy, conservative management, and the use of calcimimetics like cinacalcet. Calcimimetics mimic the action of calcium on tissues by allosteric activation of the calcium-sensing receptor.

In summary, primary hyperparathyroidism is a condition that can be asymptomatic or present with a range of symptoms. It is most commonly caused by a solitary adenoma and is associated with multiple endocrine neoplasia. Diagnosis involves blood tests and imaging, while treatment options include surgery and medication.

To diagnose diabetes mellitus, fasting blood glucose levels should be above 7.0 or random blood glucose levels should be above 11.1. If the patient is asymptomatic, two readings are required for confirmation.

Type 2 diabetes mellitus can be diagnosed through a plasma glucose or HbA1c sample. The diagnostic criteria vary depending on whether the patient is experiencing symptoms or not. If the patient is symptomatic, a fasting glucose level of 7.0 mmol/l or higher or a random glucose level of 11.1 mmol/l or higher (or after a 75g oral glucose tolerance test) indicates diabetes. If the patient is asymptomatic, the same criteria apply but must be demonstrated on two separate occasions.

In 2011, the World Health Organization released supplementary guidance on the use of HbA1c for diagnosing diabetes. A HbA1c level of 48 mmol/mol (6.5%) or higher is diagnostic of diabetes mellitus. However, a HbA1c value of less than 48 mmol/mol (6.5%) does not exclude diabetes and may not be as sensitive as fasting samples for detecting diabetes. For patients without symptoms, the test must be repeated to confirm the diagnosis. It is important to note that increased red cell turnover can cause misleading HbA1c results.

There are certain conditions where HbA1c cannot be used for diagnosis, such as haemoglobinopathies, haemolytic anaemia, untreated iron deficiency anaemia, suspected gestational diabetes, children, HIV, chronic kidney disease, and people taking medication that may cause hyperglycaemia (such as corticosteroids).

Impaired fasting glucose (IFG) is defined as a fasting glucose level of 6.1 mmol/l or higher but less than 7.0 mmol/l. Impaired glucose tolerance (IGT) is defined as a fasting plasma glucose level less than 7.0 mmol/l and an OGTT 2-hour value of 7.8 mmol/l or higher but less than 11.1 mmol/l. People with IFG should be offered an oral glucose tolerance test to rule out a diagnosis of diabetes. A result below 11.1 mmol/l but above 7.8 mmol/l indicates that the person does not have diabetes but does have IGT.

If a patient is experiencing metabolic ketoacidosis with normal or low glucose levels, alcohol consumption should be considered as a possible cause. This condition is characterized by partial respiratory compensation. While diabetic ketoacidosis could also be a potential cause, a serum glucose level of 3mmol/L makes it less likely. Therefore, the patient is more likely to be suffering from alcoholic ketoacidosis. It is important to note that a hyperosmolar hyperglycemic state would present with high serum glucose levels and normal ketone levels, while a diabetic hypoglycemic episode would not typically result in elevated ketone levels or metabolic acidosis.

Alcoholic ketoacidosis is a type of ketoacidosis that occurs in individuals who consume large amounts of alcohol regularly. This condition is not related to diabetes and is characterized by normal blood sugar levels. Alcoholics often suffer from malnutrition due to their irregular eating habits and may vomit the food they consume, leading to starvation. When the body becomes malnourished, it starts breaking down body fat, which produces ketones and leads to ketoacidosis.

The typical symptoms of alcoholic ketoacidosis include metabolic acidosis, elevated anion gap, elevated serum ketone levels, and normal or low glucose concentration. The most effective treatment for this condition is an infusion of saline and thiamine. Thiamine is essential to prevent the development of Wernicke encephalopathy or Korsakoff psychosis. Therefore, it is crucial to provide timely and appropriate treatment to individuals suffering from alcoholic ketoacidosis to prevent further complications.

On the day of surgery, sulfonylureas should be omitted, except for patients who take them twice a day. In this case, the morning dose should be withheld, and the afternoon dose given after the surgery. This is because there is a risk of hypoglycemia in the fasted state before surgery. Withholding both doses or withholding for 24 or 48 hours is incorrect. The BNF website provides a comprehensive guide for managing diabetic patients on insulin and anti-diabetic drugs during surgery, including information on when to introduce variable rate insulin infusions and withholding anti-diabetic medications.

Preparation for surgery varies depending on whether the patient is undergoing an elective or emergency procedure. For elective cases, it is important to address any medical issues beforehand through a pre-admission clinic. Blood tests, urine analysis, and other diagnostic tests may be necessary depending on the proposed procedure and patient fitness. Risk factors for deep vein thrombosis should also be assessed, and a plan for thromboprophylaxis formulated. Patients are advised to fast from non-clear liquids and food for at least 6 hours before surgery, and those with diabetes require special management to avoid potential complications. Emergency cases require stabilization and resuscitation as needed, and antibiotics may be necessary. Special preparation may also be required for certain procedures, such as vocal cord checks for thyroid surgery or bowel preparation for colorectal cases.