Endocrinology Flashcards
A 10-year-old girl was diagnosed with diabetes 1 year ago. She has been compliant with her insulin regimen and her HBA1c is 6 per cent. She is attending her annual diabetic review and has been asking about why she has diabetes. What is the aetiology of type 1 diabetes?
A. Inflammation of the pancreas causing exocrine and endocrine dysfunction
B. Impaired glucose tolerance
C. Secretory dysfunction of the pancreatic duct
D. Autoimmune destruction of pancreatic islet cells
E. Peripheral insulin resistance
D. Autoimmune destruction of pancreatic islet cells
1 DType 1 diabetes is due to autoimmune destruction of the B cells of the islets of Langerhans in the pancreas. This leads to absolute insulin deficiency and a state of catabolism, particularly lipids, in the absence of insulin. These children are dependent on exogenous insulin for life. Type 2 diabetes is due to reduced production of insulin but also peripheral resistance in tissues (E). Diabetes may be acquired with other conditions such as chronic pancreatitis (A), corticosteroid use (B) or cystic fibrosis (C).
A 2-year-old girl was brought by her mother to accident and emergency after 4 days of vomiting and abdominal pain. She had brought her in 2 days ago after developing a cold and was discharged home and diagnosed with a ‘tummy bug’. On examination, she was drowsy, had dry mucous membranes, deep heavy breathing, cool peripheries and tachycardia. Her mother reports a 1-month history of weight loss, excessive drinking and passing large volumes of urine prior to this episode. Her urine dipstick has ketones and glucose. Her blood gas shows the following: pH 7.10, PCO2 kPa 2.1, PO2 kPa 10.0, BE −12, HCO3 – mmol/L 18. What is
the most likely diagnosis?
A. Severe dehydration secondary to gastroenteritis
B. Sepsis secondary to gastroenteritis
C. Diabetic ketoacidosis (DKA)
D. Chronic kidney disease
E. Hyperosmolar hyperglycaemic non-ketotic state
C. Diabetic ketoacidosis (DKA)
2 CThis girl has the classical history of developing polyuria and polydipsia with weight loss, now with a viral illness precipitating DKA (C). Abdominal pain and vomiting are common in DKA and the disease process is triggered by insulin deficiency leading to lipolysis and ketone production. This results in the acidosis along with glycosuria osmotically increasing water losses in urine and leads to dehydration, worsening the acidosis. She will likely have high blood sugar which should also be measured in the laboratory as the bedside tests are inaccurate at very high levels. Gastroenteritis ((A) and (B)) can cause both profound dehydration and sepsis (with bacteraemia or viraemia), with ketonuria but there should not be glycosuria. Children with polyuria should have renal function checked (D), but in this setting with acute illness and ketonuria and glycosuria suggestive of DKA, diabetes is a better explanation of polyuria. Hyperosmolar hyperglycaemic non-ketotic state (E) occurs as a complication of type 2 diabetes, which is rare in childhood and does not present with ketonuria, though the incidence is increasing with childhood obesity.
A 3-week-old baby is brought to the ‘prolonged jaundice clinic’. His mother reports he has poor feeding, is not gaining weight appropriately and is more sleepy compared to her previous child. He opens his bowel once a day and is being mix breast and bottle fed. He is floppy, jaundiced, has a large, protruding tongue and a hoarse cry. He had a newborn blood spot screening test done at birth which was normal and he has no dysmorphic features. What is the most likely diagnosis of this child?
A. Beckwith–Wiedemann syndrome
B. Congenital hypothyroidism
C. Down’s syndrome
D. Normal baby
E. Prader–Willi syndrome
B. Congenital hypothyroidism
3 B This child has many features of hypothyroidism (B). Children with prolonged jaundice should have their thyroid function tested. The newborn blood spot tests for high thyroid-stimulating hormone (TSH) levels in response to low thyroxine, which should detect most congenital hypothyroidism. Rarely, in children with panhypopituitarism, there is low TSH and therefore low thyroxine. Babies with Down’s syndrome (C) can also have hypotonia (floppiness), poor feeding and weight gain, macroglossia and hypothyroidism but with typical facial features which are not present here. Other conditions causing macroglossia include Beckwith–Wiedemann syndrome (A) (other features would include: fetal macrosomia, hypoglycaemia secondary to hyperinsulinaemia, hemihypertrophy, abnormal ear development). Other conditions causing hypotonia and poor feeding include Prader–Willi syndrome (obesity and learning difficulties in later life) (E). This is not a normal baby (D) as jaundice beyond 2 weeks is pathological.
A 10-year-old girl with Graves’ disease attends her GP with worsening of her symptoms. She was well controlled on carbimazole and has had relatively few symptoms for the past 6 months. She now has sweats, weight loss, diarrhoea and tremors which are affecting her school performance. What is the next management step?
A. Review in 3 months
B. Radioisotope therapy
C. Stop carbimazole and start propranolol
D. Optimize carbimazole dose and add propanolol
E. Referral for thyroidectomy
D. Optimize carbimazole dose and add propanolol
4 D Hyperthyroidism is due to raised thyroxine which may be due to high pituitary stimulation (high TSH) or endogenous thyroid production (low TSH). The symptoms are multisystemic and include tachycardia, heat intolerance, diarrhoea, weight loss, amenorrhoea, tremor and psychosis. Carbimazole acts to suppress thyroxine production and therefore reduce symptoms. This girl has got worsening symptoms and therefore the first course of action would be to optimize the dose of carbimazole to reduce the production of thyroxine, and then add propranolol which can be given for symptomatic relief, especially for tremors (D). Propranolol is not a replacement for carbimazole as it does not directly affect thyroxine production (C). Radioisotope treatment (B) and surgery (E) would be considered as further management strategies. (A) is not correct as she is symptomatic and therefore requires treatment to become clinically euthyroid.
A 4-year-old boy was diagnosed with nephrotic syndrome 6 months ago and has required a long course of oral corticosteroids to maintain remission of the condition. He has developed truncal obesity and you are concerned he may be developing Cushing’s syndrome. Which of the following is not a complication of Cushing’s syndrome?
A. Osteoporosis
B. Short stature
C. Gastric irritation
D. Hypertension
E. Hypoglycaemia
E. Hypoglycaemia
5 E Oral corticosteroids are required for many inflammatory or autoimmune conditions to suppress the immune response and provide symptomatic relief for patients. We can minimize the effects of steroids by ensuring we give the minimum required dosage, alternate day prescribing and weaning at the end of the treatment course. Steroids have many side effects including: hypertension (D), glucose intolerance and tendency to hyperglycaemia, not hypoglycaemia (E), weight gain causing truncal obesity and a subscapular fat pad, short stature (B), osteoporosis (A), cataracts, gastric irritation (C), striae, thinning of skin and increased bruising, proximal myopathy, increased susceptibility to infection and adrenal suppression. The truncal obesity and thin myopathic limbs is characteristic of patients on long-term steroid therapy.
A 13-year-old girl has presented to her GP with her mother with concerns that she is the shortest in her class at school. She has always been ‘on the small side’ according to her mother, despite eating well. When you examine her you find she is hypertensive but has no cardiac murmur. Respiratory and abdominal systems are normal. She has no signs of pubertal development and you notice she has widely spaced nipples and a low hair line. You are considering the diagnosis of Turner’s syndrome. What is the most appropriate diagnostic investigation? A. Mid-parental height
B. Echocardiogram
C. Four limb blood pressures
D. Karyotype
E. Fluorescence in situ hybridization (FISH)
D. Karyotype
6 DTurner’s syndrome results from the genotype 45X0. Therefore a karyotype would be diagnostic (D). FISH (E) is used to diagnose conditions caused by microdeletions in conditions such as DiGeorge’ syndrome, cri du chat syndrome and Williams’ syndrome. The four limb blood pressure (C) and an echocardiogram (B) may be useful in coarctation of the aorta and aortic stenosis which can occur as part of Turner’s syndrome but are not important in the diagnosis itself. Mid-parental height (A) is important to note in children who are short, as one of the differentials to consider is familial short stature. It is calculated by the sum of the parents’ height in centimetres, divided by 2, then +7 cm for a boy or –7 cm for a girl.
You are asked to examine a tall 15-year-old boy. His height is above the 98th centile for his age and he has other concerns about the development of breast tissue. He was told this was normal as he develops through puberty but his father states he has no facial or underarm hair. Jake allows a brief examination of his genitalia and you note he has a small penis and testicular volume. He has no arachnodactyly or visual problems. What is the most likely diagnosis?
A. Delayed onset of puberty
B. Klinefelter’s syndrome
C. Precocious puberty
D. Marfan’s syndrome
E. Normal variation
B. Klinefelter’s syndrome
7 B Both Klinefelter’s and Marfan’s syndromes (D) can result in tall stature (though associated features with Marfan’s syndrome include high arched palate, myopia, lens dislocation, arachnodactly, arm span > height, hypermobility, aortic arch abnormalities, mitral valve prolapse, chest wall deformity). Precocious puberty (C) leads to tall stature initially but ultimate height is often shorter than peers as the growth spurt occurs earlier. He also has signs of delayed puberty with small testicular volume (
A 16-year-old boy attends your GP clinic for the first time with his father. He has recently moved to the area. His father is concerned that he is shorter than his peers at school and he frequently complains about being bullied. On further questioning there is no evidence of chronic illness or familial illness and he eats a balanced diet. His weight is on the 25th centile and his height is on the 10th centile. On examination he has no evidence of facial, axillary or pubic hair, his testes are both descended and are
E. Constitutional delay
8 E The most common cause of delayed puberty is constitutional delay (E), although this is a diagnosis of exclusion. Delayed puberty is more common in boys. He does not have cryptorchidism (undescended testes) (D) on examination. Although there is a history of bullying which may in turn lead to psychological problems including anorexia nervosa (A) (rare in boys, but should be considered), his weight centile is greater than his height, making this unlikely though a body mass index should be calculated too (weight/height squared). Kallmann’s syndrome (C) is characterized by low luteinizing hormone-releasing hormone and anosmia, which is not mentioned but this disease is rare (1 in 10 000– 86 000). It is important to exclude hypothalamo-pituitary dysfunction (B) by measuring GnRH, LH and FSH but it is not the most likely cause.
A 6-year-old girl has presented to her GP with a rapid increase in growth. Her mother is also concerned that she seems to have developed pubic and axillary hair and breast development prior to this but thought it would go away. She has no history of trauma and has reported problems with her vision. Her levels of gonadotrophin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH) and oestrogen are high. You are concerned that she may have a pituitary tumour. What is the likely visual field defect?
A. Monocular blindness
B. Central scotoma
C. Homonymous hemianopia
D. Bitemporal hemianopia
E. Myopia
D. Bitemporal hemianopia
9 DThis girl has features consistent with precocious puberty, which is the onset of puberty at
A 9-year-old girl presents to accident and emergency with fever, vomiting and dysuria. She is wearing a steroid bracelet and has a steroid card stating she is on daily prednisolone for severe asthma and eczema and is therefore at risk of adrenal suppression. She is tachycardic at 140 bpm and you are concerned that her blood pressure is low. Her capillary glucose is 3.0 mmol/L. What is the single most important investigation?
A. Cortisol
B. Full blood count
C. Renal function tests
D. Urine culture
E. Blood culture
C. Renal function tests
10 C This girl is having an Addisonian crisis. She has been on long-term corticosteroids and is therefore at high risk of having developed adrenal suppression. She has subsequently developed a urinary tract infection and the physiological response would be to increase endogenous steroid production. However, with her hypothalamic-pituitary-adrenal axis down-regulated due to her exogenous steroid use, this is not possible. She therefore is steroid depleted. She has hypotension, hypoglycaemia and is likely to develop hyperkalaemia and hyponatraemia. Cortisol (A) is likely to be low, but this will not change your management of her condition. Full blood count (B), urine culture (D) and blood culture (E) may help to elucidate the cause of the deterioration and treat it, but will not provide information about the Addisonian crisis. Renal function (C) is important to identify hyponatraemia and hyperkalaemia which may require treatment. Hydrocortisone and IV dextrose would be the initial treatment of choice, with antibiotics.
