A phaeochromocytoma is an uncommon functional tumor that develops from chromaffin cells in the adrenal medulla. Extra-adrenal paragangliomas, also known as extra-adrenal pheochromocytomas, are closely associated but less prevalent tumors that originate in the ganglia of the sympathetic nervous system. These tumors release catecholamines and result in a range of symptoms and indications linked to hyperactivity of the sympathetic nervous system.

Cushing syndrome is most commonly caused by the use of external glucocorticoids. However, when it comes to endogenous causes, pituitary adenoma, also known as Cushing’s disease, is the leading culprit.

Further Reading:

Cushing’s syndrome is a clinical syndrome caused by prolonged exposure to high levels of glucocorticoids. The severity of symptoms can vary depending on the level of steroid exposure. There are two main classifications of Cushing’s syndrome: ACTH-dependent disease and non-ACTH-dependent disease. ACTH-dependent disease is caused by excessive ACTH production from the pituitary gland or ACTH-secreting tumors, which stimulate excessive cortisol production. Non-ACTH-dependent disease is characterized by excess glucocorticoid production independent of ACTH stimulation.

The most common cause of Cushing’s syndrome is exogenous steroid use. Pituitary adenoma is the second most common cause and the most common endogenous cause. Cushing’s disease refers specifically to Cushing’s syndrome caused by an ACTH-producing pituitary tumor.

Clinical features of Cushing’s syndrome include truncal obesity, supraclavicular fat pads, buffalo hump, weight gain, moon facies, muscle wasting and weakness, diabetes or impaired glucose tolerance, gonadal dysfunction, hypertension, nephrolithiasis, skin changes (such as skin atrophy, striae, easy bruising, hirsutism, acne, and hyperpigmentation in ACTH-dependent causes), depression and emotional lability, osteopenia or osteoporosis, edema, irregular menstrual cycles or amenorrhea, polydipsia and polyuria, poor wound healing, and signs related to the underlying cause, such as headaches and visual problems.

Diagnostic tests for Cushing’s syndrome include 24-hour urinary free cortisol, 1 mg overnight dexamethasone suppression test, and late-night salivary cortisol. Other investigations aim to assess metabolic disturbances and identify the underlying cause, such as plasma ACTH, full blood count (raised white cell count), electrolytes, and arterial blood gas analysis. Imaging, such as CT or MRI of the abdomen, chest, and/or pituitary, may be required to assess suspected adrenal tumors, ectopic ACTH-secreting tumors, and pituitary tumors. The choice of imaging is guided by the ACTH result, with undetectable ACTH and elevated serum cortisol levels indicating ACTH-independent Cushing’s syndrome and raised ACTH suggesting an ACTH-secreting tumor.

The secretion of aldosterone occurs in the zona glomerulosa of the adrenal cortex.

Further Reading:

Hyperaldosteronism is a condition characterized by excessive production of aldosterone by the adrenal glands. It can be classified into primary and secondary hyperaldosteronism. Primary hyperaldosteronism, also known as Conn’s syndrome, is typically caused by adrenal hyperplasia or adrenal tumors. Secondary hyperaldosteronism, on the other hand, is a result of high renin levels in response to reduced blood flow across the juxtaglomerular apparatus.

Aldosterone is the main mineralocorticoid steroid hormone produced by the adrenal cortex. It acts on the distal renal tubule and collecting duct of the nephron, promoting the reabsorption of sodium ions and water while secreting potassium ions.

The causes of hyperaldosteronism vary depending on whether it is primary or secondary. Primary hyperaldosteronism can be caused by adrenal adenoma, adrenal hyperplasia, adrenal carcinoma, or familial hyperaldosteronism. Secondary hyperaldosteronism can be caused by renal artery stenosis, reninoma, renal tubular acidosis, nutcracker syndrome, ectopic tumors, massive ascites, left ventricular failure, or cor pulmonale.

Clinical features of hyperaldosteronism include hypertension, hypokalemia, metabolic alkalosis, hypernatremia, polyuria, polydipsia, headaches, lethargy, muscle weakness and spasms, and numbness. It is estimated that hyperaldosteronism is present in 5-10% of patients with hypertension, and hypertension in primary hyperaldosteronism is often resistant to drug treatment.

Diagnosis of hyperaldosteronism involves various investigations, including U&Es to assess electrolyte disturbances, aldosterone-to-renin plasma ratio (ARR) as the gold standard diagnostic test, ECG to detect arrhythmia, CT/MRI scans to locate adenoma, fludrocortisone suppression test or oral salt testing to confirm primary hyperaldosteronism, genetic testing to identify familial hyperaldosteronism, and adrenal venous sampling to determine lateralization prior to surgery.

Treatment of primary hyperaldosteronism typically involves surgical adrenalectomy for patients with unilateral primary aldosteronism. Diet modification with sodium restriction and potassium supplementation may also be recommended.

Cerebral edema is the most significant complication of diabetic ketoacidosis (DKA), leading to death in many cases. It occurs in approximately 0.2-1% of DKA cases. The high blood glucose levels cause an osmolar gradient, resulting in the movement of water from the intracellular fluid (ICF) to the extracellular fluid (ECF) space and a decrease in cell volume. When insulin and intravenous fluids are administered to correct the condition, the effective osmolarity decreases rapidly, causing a reversal of the fluid shift and the development of cerebral edema.

Cerebral edema is associated with a higher mortality rate and poor neurological outcomes. To prevent its occurrence, it is important to slowly normalize osmolarity over a period of 48 hours, paying attention to glucose and sodium levels, as well as ensuring proper hydration. Monitoring the child for symptoms such as headache, recurrent vomiting, irritability, changes in Glasgow Coma Scale (GCS), abnormal slowing of heart rate, and increasing blood pressure is crucial.

If cerebral edema does occur, it should be treated with either a hypertonic (3%) saline solution at a dosage of 3 ml/kg or a mannitol infusion at a dosage of 250-500 mg/kg over a 20-minute period.

In addition to cerebral edema, there are other complications associated with DKA in children, including cardiac arrhythmias, pulmonary edema, and acute renal failure.

Of all the medications mentioned in this question, only pioglitazone is known to be a potential cause of hypoglycemia. Glucagon, on the other hand, is specifically used as a treatment for hypoglycemia. The remaining medications mentioned are antidiabetic drugs that do not typically lead to hypoglycemia when used alone.

Metformin is a type of biguanide medication that, when taken alone, does not lead to low blood sugar levels (hypoglycemia). However, it can potentially worsen hypoglycemia when used in combination with other drugs like sulphonylureas.

Gliclazide, on the other hand, is a sulphonylurea medication known to cause hypoglycemia. Pioglitazone, a thiazolidinedione drug, is also recognized as a cause of hypoglycemia.

It’s important to note that Actrapid and Novomix are both forms of insulin, which can also result in hypoglycemia.

After the fluid restriction period, the urine is checked to determine if it remains relatively dilute (less than 600 mOsm/kg). If it does, desmopressin is administered and the urine is rechecked to see if it responds and becomes more concentrated.

If the urine osmolality significantly increases after desmopressin, it indicates that the kidneys have responded appropriately to the medication and the urine has concentrated. This suggests that the patient is not producing ADH in response to water loss, indicating cranial DI.

It is important to note that some units may use a lower cut-off of greater than 600 mOsm/kg instead of 800 mOsm/kg.

Further Reading:

Diabetes insipidus (DI) is a condition characterized by either a decrease in the secretion of antidiuretic hormone (cranial DI) or insensitivity to antidiuretic hormone (nephrogenic DI). Antidiuretic hormone, also known as arginine vasopressin, is produced in the hypothalamus and released from the posterior pituitary. The typical biochemical disturbances seen in DI include elevated plasma osmolality, low urine osmolality, polyuria, and hypernatraemia.

Cranial DI can be caused by various factors such as head injury, CNS infections, pituitary tumors, and pituitary surgery. Nephrogenic DI, on the other hand, can be genetic or result from electrolyte disturbances or the use of certain drugs. Symptoms of DI include polyuria, polydipsia, nocturia, signs of dehydration, and in children, irritability, failure to thrive, and fatigue.

To diagnose DI, a 24-hour urine collection is done to confirm polyuria, and U&Es will typically show hypernatraemia. High plasma osmolality with low urine osmolality is also observed. Imaging studies such as MRI of the pituitary, hypothalamus, and surrounding tissues may be done, as well as a fluid deprivation test to evaluate the response to desmopressin.

Management of cranial DI involves supplementation with desmopressin, a synthetic form of arginine vasopressin. However, hyponatraemia is a common side effect that needs to be monitored. In nephrogenic DI, desmopressin supplementation is usually not effective, and management focuses on ensuring adequate fluid intake to offset water loss and monitoring electrolyte levels. Causative drugs need to be stopped, and there is a risk of developing complications such as hydroureteronephrosis and an overdistended bladder.

The most probable diagnosis in this case is diabetic ketoacidosis (DKA). To confirm the diagnosis, it is necessary to establish that his blood glucose levels are elevated, he has significant ketonuria or ketonaemia, and that he is acidotic.

DKA is a life-threatening condition that occurs when there is a lack of insulin, leading to an inability to metabolize glucose. This results in high blood sugar levels and an osmotic diuresis, causing excessive thirst and increased urine production. Dehydration becomes inevitable when the urine output exceeds the patient’s ability to drink. Additionally, without insulin, fat becomes the primary energy source, leading to the production of large amounts of ketones and metabolic acidosis.

The key features of DKA include hyperglycemia (blood glucose > 11 mmol/l), ketonaemia (> 3 mmol/l) or significant ketonuria (> 2+ on urine dipstick), and acidosis (bicarbonate < 15 mmol/l and/or venous pH < 7.3). Clinical symptoms of DKA include nausea, vomiting, excessive thirst, excessive urine production, abdominal pain, signs of dehydration, a smell of ketones on breath (similar to pear drops), deep and rapid respiration (Kussmaul breathing), confusion or reduced consciousness, and tachycardia, hypotension, and shock. Investigations that should be performed include blood glucose measurement, urine dipstick (which will show marked glycosuria and ketonuria), blood ketone assay (more sensitive and specific than urine dipstick), blood tests (full blood count and urea and electrolytes), and arterial or venous blood gas analysis to assess for metabolic acidosis. The main principles of managing DKA are as follows: – Fluid boluses should only be given to reverse signs of shock and should be administered slowly in 10 ml/kg aliquots. If there are no signs of shock, fluid boluses should not be given, and specialist advice should be sought if a second bolus is required.
– Rehydration should be done with replacement therapy over 48 hours after signs of shock have been reversed.
– The first 20 ml/kg of fluid resuscitation should be given in addition to replacement fluid calculations and should not be subtracted from the calculations for the 48-hour fluid replacement.
– If a child in DKA shows signs of hypotensive shock, the use of inotropes may be considered.

This woman is experiencing hypoglycemia, most likely due to her treatment with glibenclamide. Hypoglycemia is defined as having a blood glucose level below 3.0 mmol/l, and it is crucial to promptly treat this condition to prevent further complications such as seizures, stroke, or heart problems.

If the patient is conscious and able to swallow, a fast-acting carbohydrate like sugar or GlucoGel can be given orally. However, since this woman is unconscious, this option is not feasible.

In cases where intravenous access is available, like in this situation, an intravenous bolus of dextrose should be administered. The recommended doses are either 75 mL of 20% dextrose or 150 mL of 10% dextrose.

When a patient is at home and intravenous access is not possible, the preferred initial treatment is glucagon. Under these circumstances, 1 mg of glucagon can be given either intramuscularly (IM) or subcutaneously (SC).

It is important to note that immediate action is necessary to address hypoglycemia and prevent any potential complications.

Nelson’s syndrome is a rare condition that occurs many years after a bilateral adrenalectomy for Cushing’s syndrome. It is believed to develop due to the loss of the normal negative feedback control that suppresses high cortisol levels. As a result, the hypothalamus starts producing CRH again, which stimulates the growth of a pituitary adenoma that produces adrenocorticotropic hormone (ACTH).

Only 15-20% of patients who undergo bilateral adrenalectomy will develop this condition, and it is now rarely seen as the procedure is no longer commonly performed.

The symptoms and signs of Nelson’s syndrome are related to the growth of the pituitary adenoma and the increased production of ACTH and melanocyte-stimulating hormone (MSH) from the adenoma. These may include headaches, visual field defects (up to 50% of cases), increased skin pigmentation, and the possibility of hypopituitarism.

ACTH levels will be significantly elevated (usually >500 ng/L). Thyroxine, TSH, gonadotrophin, and sex hormone levels may be low. Prolactin levels may be high, but not as high as with a prolactin-producing tumor. MRI or CT scanning can be helpful in identifying the presence of an expanding pituitary mass.

The treatment of choice for Nelson’s syndrome is trans-sphenoidal surgery.