In central and nephrogenic diabetes insipidus (DI), urinary osmolality will be less than 300 mOsm/kg after water deprivation. After the administration of ADH, the osmolality will rise to more than 750 mOsm/kg in central DI but will not rise at all in nephrogenic DI.

In primary polydipsia, water deprivation results in an increase in urine osmolality, anywhere between 300 – 800 mOsm/Kg (usually up to 600 – 700 mOsm/Kg), without a substantial increase in plasma osmolality, but the increase in urine osmolality is not as substantial as in a normal response.

Elderly patients with severe hypothyroidism often present with variable symptoms that may be masked or potentiated by co-morbid conditions. Characteristic symptoms may include fatigue, weight gain, cold intolerance, hoarseness, constipation, and myalgias. Neurologic symptoms may include ataxia, depression, and mental status changes ranging from mild confusion to overt dementia.
Clinical findings that may raise suspicion of thyroid hormone deficiency include hypothermia, bradycardia, goitrous enlargement of the thyroid, cool dry skin, myxoedema, delayed relaxation of deep tendon reflexes, a pericardial or abdominal effusion, hyponatremia, and hypercholesterolemia.

The patient has a greatly reduced free T4 concentration, is hypothermic, unconscious and has evidence of associated heart failure. All of those support the diagnosis of profound hypothyroidism.

The level of haemoglobin A1c (HbA1c), also known as glycated haemoglobin, determines how well a patient’s blood glucose level has been controlled over the previous 8–12 weeks. Recent studies have been made to correlate between HbA1c and average glucose level.
Using the following formula: Average blood glucose (mmol/l) = (1.98 x 1 HbA1c) – 4.29

The somatotroph cells of the anterior pituitary gland produce growth hormone (GH).
GH deficiency in adults usually manifests as reduced physical performance and impaired psychological well-being. It results in alterations in the physiology of different systems of the body, manifesting as altered lipid metabolism, increased subcutaneous and visceral fat, decreased muscle mass, decreased bone density, low exercise performance, and reduced quality of life.

Hyperthyroid patients show significantly lower resting arterial CO2 tension, tidal volume and significantly higher mean inspiratory flow and pa(O2) than healthy patients. This may of course lead to misdiagnosis of patients with hyperthyroidism as having hyperventilation syndrome.

The patient has Cushing syndrome suggested by the elevated 24hr urine free cortisol. Hence, the mass is most probably a cortisol secreting adenoma.

The empty boxes indicate that the patient has run out of his medication.
Chronic administration of high doses of glucocorticoids (GCs) (e.g., prednisone or prednisolone) and also other hormones such as oestrogens, progestins, androgens and growth hormone induce varying degrees of tolerance, resulting in a progressively decreased response to the effect of the drug, followed by dependence and rarely addiction.
The glucocorticoid withdrawal syndrome (GWS) has been considered a withdrawal reaction due to established physical dependence on supraphysiological GC levels.
The severity of GWS depends on the genetics and developmental history of the patient, on his environment, and on the phase and degree of dependence the patient has reached. Its management should include a temporary increase in the dose of GCs followed by gradual, slow tapering to a maintenance dose.

Diabetes insipidus (DI) is defined as the passage of large volumes (>3 L/24 hr) of dilute urine (< 300 mOsm/kg). It has the following 2 major forms:
Central (neurogenic, pituitary, or neurohypophyseal) DI, characterized by decreased secretion of antidiuretic hormone (ADH; also referred to as arginine vasopressin [AVP])
Nephrogenic DI, characterized by decreased ability to concentrate urine because of resistance to ADH action in the kidney.
The boy most probably has nephrogenic diabetes insidious (DI) not central DI so he is not responding to the ADH treatment.

Primary hyperaldosteronism, also known as Conn’s Syndrome, is one of the most common causes of secondary hypertension (HTN).
The common clinical scenarios in which the possibility of primary hyperaldosteronism should be considered include the following:
– Patients with spontaneous or unprovoked hypokalaemia, especially if the patient is also hypertensive
– Patients who develop severe and/or persistent hypokalaemia in the setting of low to moderate doses of potassium-wasting diuretics
– Patients with treatment-refractory/-resistant hypertension (HTN)
Patients with severe hypokalaemia report fatigue, muscle weakness, cramping, headaches, and palpitations. They can also have polydipsia and polyuria from hypokalaemia-induced nephrogenic diabetes insipidus. Long-standing HTN may lead to cardiac, retinal, renal, and neurologic problems, with all the associated symptoms and signs.

Dapagliflozin works by inhibiting sodium glucose cotransporter 2 (SGLT2) and blocking resorption of glucose in the kidney, leading to an increase in urinary glucose excretion and lowering of both plasma glucose levels and body weight.
All studies with SGLT2 inhibitors have found significant reductions in BP, with greater reductions seen in systolic (1.66 to 6.9mmHg) than diastolic (0.88 to 3.5mmHg) BP.
While some trials have shown no change in lipid parameters, others have shown a modest but statistically significant increase in both HDL and LDL cholesterol with no effect on triglycerides or the LDL/HDL ratio.

The patient has primary Hypogonadism.
Since he already had two children, Klinefelter syndrome is excluded and the patient does not need karyotyping.
His lab results are normal indicating normal pituitary gland functions.
So the next step is testicular ultrasound as testicular tumour, infiltration or idiopathic failure is suspected.

Klinefelter syndrome (KS), the most common human sex chromosome disorder 47,XXY. It is characterized by hypogonadism (micro-orchidism, oligospermia/azoospermia) and gynecomastia in late puberty. If Klinefelter syndrome is not diagnosed prenatally, a patient with 47,XXY karyotype may demonstrate various subtle, age-related clinical signs that would prompt diagnostic testing. These include the following:
Infants: Hypospadias, small phallus, cryptorchidism.
Toddlers: Developmental delay (especially expressive language skills), hypotonia.
Older boys and adolescent males: Tall stature; delayed or incomplete pubertal development with eunuchoid body habitus; gynecomastia; small, firm testes; sparse body hair.

From childhood with progression to early puberty, the pituitary-gonadal function observed is within normal limits for 47,XXY males.
At mid puberty and later, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) concentrations rise to hyper-gonadotropic levels, inhibin B levels fall until they are undetectable, and testosterone levels are at low or low-normal levels after an initial increase.

Fragile X syndrome, also termed Martin-Bell syndrome or marker X syndrome, is the most common cause of inherited mental retardation, intellectual disability, and autism.
However, the patient here does not have any mental disabilities as he already works as a clerk, and that too would make Down’s Syndrome less likely.

Classic Kallmann syndrome (KS) and idiopathic hypogonadotropic hypogonadism (IHH) are rare genetic conditions that encompass the spectrum of isolated hypogonadotropic hypogonadism. Most patients have gonadotropin-releasing hormone (GnRH) deficiency, as suggested by their response to pulsatile GnRH therapy. Hypothalamic-pituitary function is otherwise normal in most patients, and hypothalamic-pituitary imaging reveals no space-occupying lesions. By definition, either anosmia or severe hyposmia is present in patients with Kallmann syndrome, in contrast to patients with idiopathic hypogonadotropic hypogonadism, whose sense of smell is normal.

The patient has a non-functioning pituitary tumour as her hormone profile is normal.
Non-functioning pituitary tumours are relatively common. A large number of these tumours are incidentally found pituitary microadenomas (<1 cm) and are usually of no clinical importance.

The combination of Insulinoma and Parathyroid diseases is suggestive of MEN 1 syndrome.
Multiple endocrine neoplasia type 1 (MEN1) is a rare hereditary tumour syndrome inherited in an autosomal dominant manner and characterized by a predisposition to a multitude of endocrine neoplasms primarily of parathyroid, entero-pancreatic, and anterior pituitary origin, as well as non-endocrine neoplasms.
Other endocrine tumours in MEN1 include foregut carcinoid tumours, adrenocortical tumours, and rarely pheochromocytoma. Nonendocrine manifestations include meningiomas and ependymomas, lipomas, angiofibromas, collagenomas, and leiomyomas.

Primary hyperparathyroidism (PHPT), due to parathyroid hyperplasia is the most frequent and usually the earliest expression of MEN-1, with a typical age of onset at 20–25 years.

Insulin remains the standard of care for the treatment of uncontrolled gestational diabetes. Tight control maintained in the first trimester and throughout pregnancy plays a vital role in decreasing poor fetal outcomes, including structural anomalies, macrosomia, hypoglycaemia of the new-born, adolescent and adult obesity, and diabetes.
The baby is already large for dates so nutritional therapy can not be used alone.

Androgen insensitivity syndrome (AIS), previously referred to as testicular feminization, is an X-linked disorder in which the patients are genotypically male (possessing and X and Y chromosome) and phenotypically female. This disorder is rare, with reported incidences from 1 in 20,000 to 1 in 60,000 live male births, and is the result of a missing gene on the X chromosome that is responsible for the cytoplasmic or nuclear testosterone receptor. In its absence, the gonad, which is a testis, produces normal amounts of testosterone; however, the end tissues are unable to respond due to the deficient receptors leading to the external genitalia developing in a female fashion. Anti-mullerian hormone, which is produced by the testis, is normal in these patients, leading to regression of the Mullerian duct. Wolffian duct development, which depends on testosterone, does not occur as the ducts lack the receptors.
The cumulative effect is a genotypic male with normal external female genitalia (without pubic or axillary hair), no menses, normal breast development, short or absent vagina, no internal sex organs, and the presence of testis. Frequently, these patients have bilateral inguinal hernias in childhood, and their presence should arouse suspicion of the diagnosis.

This child has pseudo hypoparathyroidism. It is a heterogeneous group of rare endocrine disorders characterized by normal renal function and resistance to the action of parathyroid hormone (PTH), manifesting with hypocalcaemia, hyperphosphatemia, and increased serum concentration of PTH.
Patients with pseudo hypoparathyroidism type 1a present with a characteristic phenotype collectively called Albright hereditary osteodystrophy (AHO). The constellation of findings includes the following:
Short stature
Stocky habitus
Obesity
Developmental delay
Round face
Dental hypoplasia
Brachymetacarpals
Brachymetatarsals
Soft tissue calcification/ossification
The goals of therapy are to maintain serum total and ionized calcium levels within the reference range to avoid hypercalcaemia and to suppress PTH levels to normal. This is important because elevated PTH levels in patients with PHP can cause increased bone remodelling and lead to hyper-parathyroid bone disease.
The goals of pharmacotherapy are to correct calcium deficiency, to prevent complications, and to reduce morbidity. Intravenous calcium is the initial treatment for all patients with severe symptomatic hypocalcaemia. Administration of oral calcium and 1alpha-hydroxylated vitamin D metabolites, such as calcitriol, remains the mainstay of treatment and should be initiated in every patient with a diagnosis of pseudo hypoparathyroidism.

This patient has hypercalcaemia due to hyperparathyroidism. However, the intestinal absorption of calcium is mainly controlled by 1,25 dihydroxy-vitamin D. Under the influence of calcitriol (active form of vitamin D), intestinal epithelial cells increase their synthesis of calbindin (calcium-binding carrier protein) necessary for active calcium ion absorption.

Primary hyperparathyroidism (PHPT) is diagnosed based upon levels of blood calcium and parathyroid hormone (PTH). In most people with PHPT, both levels are higher than normal. Occasionally, a person may have an elevated calcium level and a normal or minimally elevated PTH level. Since PTH should normally be low when calcium is elevated, a minimally elevated PTH is considered abnormal and indicates PHPT.

Selective sodium-glucose transporter-2 (SGLT2) is expressed in the proximal renal tubules and is responsible for the majority of the reabsorption of filtered glucose from the tubular lumen.
Empagliflozin; SGLT2 inhibitors reduce glucose reabsorption and lower the renal threshold for glucose, thereby increasing urinary glucose excretion, thus increasing the risk of urinary tract infections.

As the patient has early menopause, hormone replacement therapy (HT) is considered to be the first line of choice for prevention of bone loss and fracture in the early postmenopausal period for 5 years.

The patients high morning blood sugar levels are suggestive to Somogyi Phenomenon which suggests that hypoglycaemia during the late evening induced by insulin could cause a counter regulatory hormone response that produces hyperglycaemia in the early morning.
Substitution of regular insulin with an immediate-acting insulin analogue, such as Humulin lispro, may be of some help.

The patient has hyperprolactinaemia with otherwise normal oestradiol, FSH and LH. This is highly suggestive of Prolactinoma rather than a non functioning tumour.
In polycystic ovaries, there is increase in the level of LH while FSH is normal or low.

The clinical manifestations of Small cell lung cancer (SCLC) can result from local tumour growth, intrathoracic spread, distant spread, and/or paraneoplastic syndromes.
Hypertrophic pulmonary osteoarthropathy (HPO) is a rare paraneoplastic syndrome that is frequently associated with lung cancer; however, the incidence of clinically apparent HPO is not well known.
SIADH is present in 15% of cases and most commonly seen.
Although hypercalcaemia is frequently associated with malignancy, it is very rare in small cell lung cancer despite the high incidence of lytic bone metastases.
Ectopic Cushing’s syndrome in SCLC does not usually exhibit the classic signs of Cushing’s syndrome and Cushing’s syndrome could also appear during effective chemotherapy.
Chemotherapy is the treatment of choice in SCLC.

Autonomic Neuropathy may involve the cardiovascular, gastrointestinal, genitourinary systems and the sweat glands.
Patients with generalized autonomic neuropathies may report ataxia, gait instability, or near syncope/syncope. In addition, autonomic neuropathies have further symptoms that relate to the anatomic site of nerve damage—gastrointestinal, cardiovascular, bladder, or sudomotor.
– Gastrointestinal autonomic neuropathy may produce the following symptoms:
Dysphagia, abdominal pain, nausea/vomiting, malabsorption, faecal incontinence, diarrhoea, constipation.
– Cardiovascular autonomic neuropathy may produce the following symptoms :
Persistent sinus tachycardia, orthostatic hypotension, sinus arrhythmia, decreased heart variability in response to deep breathing, near syncope upon changing positions from recumbent to standing.
– Bladder neuropathy (which must be differentiated from prostate or spine disorders) may produce the following symptoms:
Poor urinary stream
Feeling of incomplete bladder emptying
Straining to void
– Sudomotor neuropathy may produce the following symptoms:
Heat intolerance
Heavy sweating of head, neck, and trunk with anhidrosis of lower trunk and extremities
Gustatory sweating

Thyroid storm, also referred to as thyrotoxic crisis, is an acute, life-threatening, hypermetabolic state induced by excessive release of thyroid hormones (THs) in individuals with thyrotoxicosis.
Patients with thyroid storm should be treated in an ICU setting for close monitoring of vital signs and for access to invasive monitoring and inotropic support, if necessary.
– Supportive measures
If needed, immediately provide supplemental oxygen, ventilatory support, and intravenous fluids. Dextrose solutions are the preferred intravenous fluids to cope with continuously high metabolic demand.
– Correct electrolyte abnormalities.
– Treat cardiac arrhythmia, if necessary.
– Aggressively control hyperthermia by applying ice packs and cooling blankets and by administering acetaminophen (15 mg/kg orally or rectally every 4 hours).
– Antiadrenergic drugs.
– Thionamides: Correct the hyperthyroid state. Administer antithyroid medications to block further synthesis of thyroid hormones (THs).
High-dose propylthiouracil (PTU) or methimazole may be used for treatment of thyroid storm.
– Administer glucocorticoids to decrease peripheral conversion of T4 to T3. This may also be useful in preventing relative adrenal insufficiency due to hyperthyroidism and improving vasomotor symptoms.
– Bile acid sequestrants prevent reabsorption of free THs in the gut (released from conjugated TH metabolites secreted into bile through the enterohepatic circulation).
– Treat the underlying condition.

RET (rearranged during transfection) is a receptor tyrosine kinase involved in the development of neural crest derived cell lineages, kidney, and male germ cells. Different human cancers, including papillary and medullary thyroid carcinomas, lung adenocarcinomas, and myeloproliferative disorders display gain-of-function mutations in RET.
In over 90% of cases, MEN2 syndromes are due to germline missense mutations of the RET gene.
Multiple endocrine neoplasias type 2 (MEN2) is an inherited disorder characterized by the development of medullary thyroid cancer (MTC), parathyroid tumours, and pheochromocytoma.

Glucagon-like peptide 1 (GLP-1) is a 30-amino acid peptide hormone produced in the intestinal epithelial endocrine L-cells by differential processing of proglucagon. GLP-1 is released in response to meal intake.
The main actions of GLP-1 are to stimulate insulin secretion (i.e., to act as an incretin hormone) and to inhibit glucagon secretion, thereby contributing to limit postprandial glucose excursions. It also inhibits gastrointestinal motility and secretion and thus acts as an enterogastrone and part of the ileal brake mechanism. GLP-1 also appears to be a physiological regulator of appetite and food intake.
Decreased secretion of GLP-1 may contribute to the development of obesity, and exaggerated secretion may be responsible for postprandial reactive hypoglycaemia.

In patients with polycystic ovarian syndrome (PCOS), FSH levels are within the reference range or low. Luteinizing hormone (LH) levels are elevated for Tanner stage, sex, and age. The LH-to-FSH ratio is usually greater than 3.

Women with PCOS have abnormalities in the metabolism of androgens and oestrogen and in the control of androgen production. PCOS can result from abnormal function of the hypothalamic-pituitary-ovarian (HPO) axis.
The major features of PCOS include menstrual dysfunction, anovulation, and signs of hyperandrogenism. Other signs and symptoms of PCOS may include the following:
– Hirsutism
– Infertility
– Obesity and metabolic syndrome
– Diabetes
– Obstructive sleep apnoea

Androgen excess can be tested by measuring total and free testosterone levels or a free androgen index. An elevated free testosterone level is a sensitive indicator of androgen excess. Other androgens, such as dehydroepiandrosterone sulphate (DHEA-S), may be normal or slightly above the normal range in patients with polycystic ovarian syndrome (PCOS). Levels of sex hormone-binding globulin (SHBG) are usually low in patients with PCOS.

Some women with PCOS have insulin resistance and an abnormal lipid profile (cholesterol >200 mg/dL; LDL >160 mg/dL). Approximately one-third of women with PCOS who are overweight have impaired glucose tolerance or type 2 diabetes mellitus by 30 years of age.

Treatment with fibrates, a widely used class of lipid-modifying agents, results in a substantial decrease in plasma triglycerides and is usually associated with a moderate decrease in LDL cholesterol and an increase in HDL cholesterol concentrations.
Evidence from studies is available to implicate 5 major mechanisms underlying the above-mentioned modulation of lipoprotein phenotypes by fibrates:
1. Induction of lipoprotein lipolysis.
2. Induction of hepatic fatty acid (FA) uptake and reduction of hepatic triglyceride production.
3. Increased removal of LDL particles. Fibrate treatment results in the formation of LDL with a higher affinity for the LDL receptor, which is thus catabolized more rapidly.
4. Reduction in neutral lipid (cholesteryl ester and triglyceride) exchange between VLDL and HDL may result from decreased plasma levels of TRL.
5. Increase in HDL production and stimulation of reverse cholesterol transport. Fibrates increase the production of apoA-I and apoA-II in the liver, which may contribute to the increase of plasma HDL concentrations and a more efficient reverse cholesterol transport.

The patient is most likely to have Addison’s disease as he has a history of autoimmune disease, hyperkalaemia and hypotension.
It is important to keep an Addisonian crisis on the differential in cases of shock, especially since adrenal crisis can be the patient’s first presentation of adrenal insufficiency.
Patients with Addison’s disease are prone to developing hypoglycaemia due to loss of the glucogenic effect of glucocorticoids. Given the sudden deterioration, a glucose level must be checked.

European guidelines for the treatment of syndrome of inappropriate antidiuresis include the following recommendations for the management of moderate or profound hyponatremia:
– Restrict fluid intake as first-line treatment.
– Second-line treatments include increasing solute intake with 0.25–0.50 g/kg per day or a combination of low-dose loop diuretics and oral sodium chloride.
– Use of lithium, demeclocycline, or vasopressin receptor antagonists is not recommended.
Recommendations on the treatment of SIADH from an American Expert Panel included the following:
– If chronic, limit the rate of correction.
– Fluid restriction should generally be first-line therapy.
– Consider pharmacologic therapies if serum Na + is not corrected after 24-48 hr of fluid restriction or if the patient has a low urinary electrolyte free water excretion.
– Patients being treated with vaptans should not be on a fluid restriction initially.
– Water, 5% dextrose or desmopressin can be used to slow the rate of correction if the water diuresis is profound.

Approximately one third of patients treated with radioiodine therapy develop transient hypothyroidism. Unless a patient is highly symptomatic, thyroxine replacement may be withheld if hypothyroidism occurs within the first 2 months of therapy. If it persists for longer than 2 months, permanent hypothyroidism is likely and replacement with T4 should be initiated.

Charcot arthropathy is a progressive condition of the musculoskeletal system that is characterized by joint dislocations, pathologic fractures, and debilitating deformities. It results in progressive destruction of bone and soft tissues at weight-bearing joints. In its most severe form, it may cause significant disruption of the bony architecture.
Charcot arthropathy can occur at any joint; however, it occurs most commonly in the lower extremity, at the foot and ankle. Diabetes is now considered to be the most common aetiology of Charcot arthropathy.

Sildenafil administration to patients who are using organic nitrates, either regularly and/or intermittently, in any form is contraindicated.
Organic nitrates and nitric oxide (NO) donors exert their therapeutic effects on blood pressure and vascular smooth muscle by the same mechanism as endogenous NO via increasing cGMP concentrations.

Achondroplasia is the most common type of short-limb disproportionate dwarfism. A single gene mapped to the short arm of chromosome 4 (band 4p16.3) is responsible for achondroplasia and is transmitted as an autosomal dominant trait. All people with achondroplasia have a short stature.
Characteristic features of achondroplasia include an average-size trunk, short arms and legs with particularly short upper arms and thighs, limited range of motion at the elbows, and an enlarged head (macrocephaly) with a prominent forehead. Fingers are typically short and the ring finger and middle finger may diverge, giving the hand a three-pronged (trident) appearance. People with achondroplasia are generally of normal intelligence.
Examination of the infant after birth shows increased front-to-back head size. There may be signs of hydrocephalus. It may be diagnosed radiographically at birth, or becomes obvious within the first year with disparity between a large skull, normal trunk length and short limbs.

Low body weight. Excessively low body weight — about 10 percent under normal weight — interrupts many hormonal functions in your body, potentially halting ovulation.
In Polycystic ovaries there is excess weight gain.

Several dipeptidyl peptidase-4 (DPP-4) inhibitors are in clinical development; these are orally active and increase levels of active glucagon-like peptide-1 (GLP-1), which in turn increases insulin secretion and reduces glucagon secretion, thereby lowering glucose levels.
Sitagliptin and vildagliptin both have a long duration of action, allowing once-daily administration. Both sitagliptin and vildagliptin are safe and tolerable with a low risk of hypoglycaemia. In drug-naïve subjects with type 2 diabetes, both sitagliptin and vildagliptin reduce A1C levels by ,1% as monotherapy.

Prolactinomas, benign lesions that produce the hormone prolactin, are the most common hormone-secreting pituitary tumours.
Based on its size, a prolactinoma can be classified as a microprolactinoma (< 10 mm diameter) or a macroprolactinoma (>10 mm diameter). If the prolactinoma is large enough to compress the surrounding normal hormone-secreting pituitary cells, it may result in deficiencies of one or more hormones (e.g., thyroid-stimulating hormone [TSH], growth hormone [GH], adrenocorticotropic hormone). However, the patient has microadenoma so it is unlikely to cause compression manifestations.
Hyperprolactinemia inhibits GnRH secretion from the medial basal hypothalamus and LH release from the pituitary.

Hashimoto thyroiditis is part of the spectrum of autoimmune thyroid diseases (AITDs) and is characterized by the destruction of thyroid cells by various cell- and antibody mediated immune processes. It usually presents with hypothyroidism, insidious in onset, with signs and symptoms slowly progressing over months to years.

The diagnosis of Hashimoto thyroiditis relies on the demonstration of circulating antibodies to thyroid antigens (mainly thyroperoxidase and thyroglobulin) and reduced echogenicity on thyroid sonogram in a patient with proper clinical features.