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.

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.

11-beta hydroxylase is stimulated by ACTH and responsible for conversion of 11-deoxycortisol to cortisol and deoxycorticosterone to corticosterone.

In 11-beta hydroxylase deficiency, the previously mentioned conversions are partially blocked, leading to:
– Increased levels of ACTH
– Accumulation of 11-deoxycortisol (which has limited biological activity) and deoxycorticosterone (which has mineralocorticoid activity)
– Overproduction of adrenal androgens (DHEA, androstenedione, and testosterone)

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

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.

Paget disease is a localized disorder of bone remodelling that typically begins with excessive bone resorption followed by an increase in bone formation. This osteoclastic over activity followed by compensatory osteoblastic activity leads to a structurally disorganized mosaic of bone (woven bone), which is mechanically weaker, larger, less compact, more vascular, and more susceptible to fracture than normal adult lamellar bone.
Approximately 70-90% of persons with Paget disease are asymptomatic; however, a minority of affected individuals experience various symptoms, including the following:
– Bone pain (the most common symptom)
– Secondary osteoarthritis (when Paget disease occurs around a joint)
– Bony deformity (most commonly bowing of an extremity)
– Excessive warmth (due to hypervascularity)
– Neurologic complications (caused by the compression of neural tissues)
Measurement of serum alkaline phosphatase—in some cases, bone-specific alkaline phosphatase (BSAP)—can be useful in the diagnosis of Paget disease. Elevated levels of urinary markers, including hydroxyproline, deoxypyridinoline, C-telopeptide, and N -telopeptide, may help identify patients with Paget disease.
Serum calcium and phosphate levels should be within the reference range in patients with Paget disease.

Oestrogen therapy reduces plasma levels of LDL cholesterol and increases levels of HDL cholesterol. It can improve endothelial vascular function, however, it also has adverse physiological effects, including increasing the plasma levels of triglycerides (small dense LDL particles). Therefore, although HRT may have direct beneficial effects on cardiovascular outcomes, these effects may be reduced or balanced by the adverse physiological effects.

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.

Graves’ disease is the most common cause of thyrotoxicosis in pregnancy.

– Poor control of thyrotoxicosis is associated with pregnancy loss, pregnancy-induced hypertension, prematurity, low birth weight, intrauterine growth restriction, stillbirth, thyroid storm, and maternal congestive heart failure.

– Antithyroid drugs are the treatment of choice of hyperthyroidism during pregnancy. The lowest dose of ATD needed to maintain TT4 1.5× the upper limit of the non-pregnant reference range or FT4 at the upper limit of the reference range should be used.
Two different antithyroid drug (ATD) regimens are in common use for Grave’s disease: i) Titration method and ii) Block-and-replace method.
In the titration method, the usual starting dose is 15–30 mg/day methimazole (or equivalent doses of other thionamides); further to periodic thyroid status assessment, daily dose is tapered down to the lowest effective dose (avoiding both hyper- and hypothyroidism).
The block-and-replace method uses persistently high ATD doses in association with L-thyroxine replacement to avoid hypothyroidism; treatment lasts 6 months. This method has advantages and disadvantages over the titration method. Higher doses of ATDs may have a greater immunosuppressive action useful for a permanent remission of hyperthyroidism, but this effect remains to be demonstrated.
Avoidance of hypothyroidism or ‘escape’ of hyperthyroidism seems easier than with the titration method; treatment is shorter, and the number of visits lower. On the other hand, the much higher number of tablets taken every day may create problems of poor compliance. The block-and-replace method should not be used during pregnancy.

– Breastfeeding has been shown to be safe in mothers taking ATDs in appropriate doses.

During pregnancy, profound changes in thyroid physiology occur to provide sufficient thyroid hormone (TH) to both the mother and foetus. This is particularly important during early pregnancy because the fetal thyroid starts to produce considerable amounts of TH only from approximately 20 weeks of gestation, until which time the foetus heavily depends on the maternal supply of TH. This supply of TH to the foetus, as well as increased concentrations of TH binding proteins (thyroxine-binding globulin) and degradation of TH by placental type 3 iodothyronine deiodinase, necessitate an increased production of maternal TH. This requires an intact thyroid gland and adequate availability of dietary iodine and is in part mediated by the pregnancy hormone human chorionic gonadotropin, which is a weak agonist of the thyroid-stimulating hormone (TSH) receptor. As a consequence, serum-free thyroxine (FT4) concentrations increase and TSH concentrations decrease from approximately the eighth week throughout the first half of pregnancy, resulting in different reference intervals for TSH and FT4 compared to the non-pregnant state.

A muscarinic receptor antagonist (MRA) is a type of anticholinergic agent that blocks the activity of the muscarinic acetylcholine receptor. There are six antimuscarinic drugs currently marketed for the treatment of urge incontinence: oxybutynin, tolterodine, propiverine, trospium, darifenacin, and solifenacin.

The patient has hyperinsulinemia and hypoglycaemia, but her C-peptide levels are normal. This is strongly suggestive of the fact that she is self-administering insulin.
In Insulinoma, common diagnostic criteria include:
– blood glucose level < 50 mg/dl with hypoglycaemic symptoms,
– relief of symptoms after eating
– absence of sulfonylurea on plasma assays.
The classic diagnostic criteria include the demonstration of the following during a supervised fast:
Increased plasma insulin level
Increased C peptide level
Increased proinsulin level
However, the patient has normal C-peptide levels.
In type-1 diabetes mellitus, insulin and C-peptide levels are low.

Elevated TSH (usually 4.5-10.0 mIU/L) with normal free T4 is considered mild or subclinical hypothyroidism.
Hypothyroidism commonly manifests as a slowing in physical and mental activity but may be asymptomatic. Symptoms and signs are often subtle and neither sensitive nor specific.
The following are symptoms of hypothyroidism:
– Fatigue, loss of energy, lethargy
– Weight gain
– Decreased appetite
– Cold intolerance
– Dry skin
– Hair loss
– Sleepiness
– Muscle pain, joint pain, weakness in the extremities
– Depression
– Emotional lability, mental impairment
– Forgetfulness, impaired memory, inability to concentrate
– Constipation
– Menstrual disturbances, impaired fertility
– Decreased perspiration
– Paraesthesia and nerve entrapment syndromes
– Blurred vision
– Decreased hearing
– Fullness in the throat, hoarseness
Physical signs of hypothyroidism include the following:
– Weight gain
– Slowed speech and movements
– Dry skin
– Jaundice
– Pallor
– Coarse, brittle, straw-like hair
– Loss of scalp hair, axillary hair, pubic hair, or a combination
– Dull facial expression
– Coarse facial features
– Periorbital puffiness
– Macroglossia
– Goitre (simple or nodular)
– Hoarseness
– Decreased systolic blood pressure and increased diastolic blood pressure
– Bradycardia
– Pericardial effusion
– Abdominal distention, ascites (uncommon)
– Hypothermia (only in severe hypothyroid states)
– Nonpitting oedema (myxoedema)
– Pitting oedema of lower extremities
– Hyporeflexia with delayed relaxation, ataxia, or both.

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.

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.

Once thyrotoxicosis has been identified by laboratory values, the thyroid radio-iodine uptake and scan may be used to help distinguish the underlying aetiology. Thyroid radioiodine uptake is raised in Graves’ disease. It may be normal or raised in patients with a toxic multinodular goitre. It is very low or undetectable in thyrotoxicosis resulting from exogenous administration of thyroid hormone or the thyrotoxic phase of thyroiditis.

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 patient is most likely to have Medullary Thyroid Carcinoma (MTC).
Sporadic, or isolated MTC accounts for 75% of cases and inherited MTC constitutes the rest.
Inherited MTC occurs in association with multiple endocrine neoplasia (MEN) type 2A and 2B syndromes, but non-MEN familial MTC also occurs.
A 24-hour urinalysis for catecholamine metabolites (e.g., vanillylmandelic acid [VMA], metanephrine) has to be done to rule out concomitant pheochromocytoma in patients with MEN type 2A or 2B, as Pheochromocytoma must be treated before MTC.

For medical management of carcinoid syndrome, there are two somatostatin analogues available, Octreotide and Lanreotide. Somatostatin is an amino acid peptide which is an inhibitory hormone, which is synthesized by paracrine cells located ubiquitously throughout the gastrointestinal tract. Both somatostatin analogues provide symptom relief in 50% to 70% of patients and biochemical response in 40% to 60% patients. Many studies have shown that Octreotide and Lanreotide also inhibit the proliferation of tumour cells.

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.

In boys, the first manifestation of puberty is testicular enlargement; the normal age for initial signs of puberty is 9 to 14 years in males. Pubic hair in boys generally appears 18 to 24 months after the onset of testicular growth and is often conceived as the initial marker of sexual maturation by male adolescents.

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.

Rotterdam criteria for the diagnosis of polycystic ovary syndrome:
Two of the following three criteria are required:
1. Oligo/anovulation
2. Hyperandrogenism
– Clinical (hirsutism or less commonly male pattern alopecia) or
– Biochemical (raised FAI or free testosterone)
3. Polycystic ovaries on ultrasound
Other aetiologies must be excluded such as congenital adrenal hyperplasia, androgen-secreting tumours, Cushing syndrome, thyroid dysfunction and hyperprolactinaemia.
Cushing’s is excluded because there would have been marked obesity, hypertension and other related features.

Exogenous thyroid hormone use has been associated with episodes of thyroid storm as well as thyrotoxic periodic paralysis.
It presents with marked proximal muscle weakness in both upper and lower limbs, hypokalaemia and signs of hyperthyroidism.
Hyperthyroidism generally presents with tachycardia, hypertension, hyperthermia, and cardiac arrhythmias

Laxatives and diuretics can result in electrolyte abnormalities.
Medical complications associated with laxatives include chronic diarrhoea which disrupts the normal stool electrolyte concentrations that then leads to serum electrolyte shifts; acutely, hypokalaemia is most typically seen. The large intestine suffers nerve damage from the chronic laxative use that renders it unable to function properly. The normal peristalsis and conduction are affected; the disorder is thought to be secondary to a degeneration of Auerbach’s Plexi. However, it does not cause muscle weakness.

Insulin tends to cause weight gain, not weight loss.
Metformin does not cause muscle weakness but can cause headaches.

Thyroid malignancies are divided into papillary carcinomas (80%), follicular carcinomas (10%), medullary thyroid carcinomas (5-10%), anaplastic carcinomas (1-2%), primary thyroid lymphomas (rare), and primary thyroid sarcomas (rare).
Hürthle cell carcinoma is a rare thyroid malignancy that is often considered a variant of follicular carcinoma.
– Papillary and Follicular carcinoma are slow-growing tumours
– Sporadic cases of Medullary thyroid carcinoma also typically manifest with painless solitary thyroid nodules in the early stages.
– Anaplastic thyroid carcinoma has the most aggressive biologic behaviour of all thyroid malignancies and has one of the worst survival rates of all malignancies in general. It manifests as a rapidly growing thyroid mass in contrast to a well-differentiated carcinoma, which are comparatively slow-growing. Patients commonly present with associated symptoms due to local invasion. Hoarseness and dyspnoea resulting from the involvement of the recurrent laryngeal nerve and airway occur in as many as 50% of patients.
– Almost all patients with primary thyroid lymphoma have either a clinical history or histological evidence of chronic lymphocytic thyroiditis. The risk of primary thyroid lymphoma increases 70-fold in patients with chronic lymphocytic thyroiditis compared with the general population. Regional and distant lymphadenopathy is common.

Classically, pheochromocytoma manifests with the following 4 characteristics:
– Headaches
– Palpitations
– Sweating
– Severe hypertension

The Endocrine Society, the American Association for Clinical Chemistry, and the European Society of Endocrinology have released clinical practice guidelines for the diagnosis and management of pheochromocytoma.
Biochemical testing via measurement of plasma free metanephrines or urinary fractionated metanephrines should be performed in patients suspected of having pheochromocytoma.

Catecholamines produced by pheochromocytomas are metabolized within chromaffin cells. Norepinephrine is metabolized to normetanephrine and epinephrine is metabolized to metanephrine. Because this process occurs within the tumour, independently of catecholamine release, pheochromocytomas are best diagnosed by measurement of these metabolites rather than by measurement of the parent catecholamines.

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.

The main cause of growth hormone (GH) deficiency is a pituitary tumour or the consequences of treatment of the tumour including surgery and/or radiation therapy.
Sheehan’s syndrome (SS) is postpartum hypopituitarism caused by necrosis of the pituitary gland. It is usually the result of severe hypotension or shock caused by massive haemorrhage during or after delivery. Patients with SS have varying degrees of anterior pituitary hormone deficiency.

Laron syndrome is Insulin-like growth factor I (IGF-I) deficiency due to GH resistance or insensitivity due to genetic disorders of the GH receptor causing GH receptor deficiency.

The patient has hyperthyroidism and its most common cause is Grave’s Disease.
Grave’s Disease is an autoimmune disease due to circulating autoantibodies known as TSH receptor stimulating autoantibodies or Thyroid-stimulating immunoglobulins (TSIs) that bind to and activate thyrotropin receptors, causing the thyroid gland to grow and the thyroid follicles to increase the synthesis of thyroid hormone.

A fasting blood glucose level from 110 to 126 mg/dL (5.5 to 6.9 mmol/L) is considered prediabetes. This result is sometimes called impaired fasting glucose.
Diabetes mellitus (type 2): diagnosis

The diagnosis of type 2 diabetes mellitus can be made by plasma glucose. If the patient is symptomatic:
fasting glucose greater than or equal to 7.0 mmol/l
random glucose greater than or equal to 11.1 mmol/l (or after 75g oral glucose tolerance test)
If the patient is asymptomatic the above criteria apply but must be demonstrated on two separate occasions.