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Endocrinology 

Endocrinology
Chapter:
Endocrinology
Author(s):

Tim Raine

, George Collins

, Catriona Hall

, Nina Hjelde

, James Dawson

, Stephan Sanders

, and Simon Eccles

DOI:
10.1093/med/9780198813538.003.0010
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► Hypoglycaemia emergency

►► Call for senior help early if patient deteriorating.

  • Blood glucose is normally >3.5mmol/L

  • Poorly controlled diabetics can have symptoms of hypoglycaemia with a glucose >3.5mmol/L.

Coma or low GCS with low glucose

  • Protect airway

  • 15L/min O2 if SOB or sats <94%

  • Establish venous access unless already present

  • Give IV glucose STAT (75–100mL of 20% or 200mL of 10%)

  • If unable to establish IV access, or for large insulin overdoses give 1mg glucagon sc/im

  • Begin to follow emergency protocol Endocrinology pp. [link][link] (low gcs)

  • If hypoglycaemia is responsible, gcs should return to 15 in <10min

  • Start 1L 10% glucose/4–8h IV, adjust rate to keep glucose >5mmol/L

  • Monitor finger-prick glucose every 30min–1h until patient stable

  • Attempt to determine the cause of the hypoglycaemia and review diabetes treatment if appropriate

  • Call for senior help

  • Reassess, starting with a, b, c; if no improvement Endocrinology pp. [link][link].

GCS 15/15 with low glucose

  • Give 15–20g of quick-acting carbohydrate (eg. 170–225mL Lucozade®) or one glucose gel (eg GlucoGel®) orally

  • Monitor finger-prick glucose 1–2h until stable, aim for >5mmol/L

  • If CBG remains <4.0 mmol/L despite 3× oral glucose, consider glucagon or IV glucose as above mentioned

  • Once the patient has recovered, give a long-acting carbohydrate (eg toast, biscuits)

  • Attempt to determine the cause of the hypoglycaemia (Box 10.1) and adjust diabetes treatment as appropriate.

Hypoglycaemia

Think about

Most likely

Excess insulin or oral hypoglycaemics in a diabetic or accidental dose in non-diabetic, alcohol;

Other

Dumping syndrome (DM or post-gastric surgery), liver failure, adrenal failure (Addison’s), pituitary insufficiency, sepsis, insulinoma, other neoplasia, malaria.

Ask about

Sweating, hunger, exercise, recent food, previous hypos and awareness,1 usual blood sugars, seizures, weight loss, tiredness, anxiety, palpitations;

PMH

dm, gastric surgery, liver or endocrine disease;

DH

Insulin dose, oral hypoglycaemic dose, compliance;

SH

Alcohol, Occupation (eg commercial driver).

Obs

hr, bp, rr, temp, gcs, recent and current blood glucose.

Look for

Pale, sweating, tremor, slurred speech, focal neurology (can be severe, eg hemiplegia), ↓GCS, abdo scars (injection sites, lipodystrophy), pigmented scars, jaundice, spider naevi, hepatomegaly.

Investigations

Finger-prick glucose

If the result is unexpected ask for a repeat on a different machine and send a blood sample in a fluoride oxalate (Endocrinology p. [link]) tube for a laboratory glucose result. If not known to be diabetic send samples for fbc, u+e, lft, glucose, insulin, C-peptide, and cortisol, prior to correcting hypoglycaemia; do not let this delay treatment.

Further investigations

Hypoglycaemia is very rare in an otherwise healthy non-diabetic patient in the absence of alcohol. Consider ‘other’ causes listed previously (also see Box 10.2). For suspected insulinoma, the investigation of choice is glucose, insulin, and C-peptide levels at the time of hypoglycaemia or after a 72h observed fast. See Endocrinology OHCM10 p. 214.

Treatment

Follow treatment for ‘Hypoglycaemia emergency’ (Endocrinology p. [link]).

DM

A single episode of mild hypoglycaemia should not prompt a change of medication. If the patient is having regular hypos then consider a dose reduction, especially if lack of awareness of hypoglycaemic episodes. Try to establish any diurnal pattern of hypos, then reduce appropriate insulin dose by 20%; consult BNF to reduce the doses of oral hypoglycaemics. Ensure the patient is aware of the sick day rules (Endocrinology Box 10.7 p. [link]).

Alcohol

Hypoglycaemia following alcohol will not reoccur after correction in the absence of further alcohol consumption. Once the patient’s blood sugars are stable they can be discharged.

Dumping syndrome

Fast passage of food into the small intestine (following gastric surgery or in severe diabetic autonomic neuropathy) can cause fluid shifts and rapid glucose absorption. Excessive insulin secretion results in rebound hypoglycaemia 1–3h after a meal. A diet low in glucose and high in fibre will improve the symptoms. Aim for frequent, smaller meals.

Neoplasia

If suspected, arrange appropriate imaging and referral

► Hyperglycaemia emergency

►► Call for senior help early if patient deteriorating.

Diabetic ketoacidosis (DKA)

(Endocrinology p. [link].)

  • 15L/minO2 if SOB or sats <94%

  • Call for senior help

  • Establish venous access, take bloods:

    • fbc, u+e, glucose, osmolality, hco3, bld cultures

  • Check BP:

    • if SBP<90mmHg, give 500mL 0.9% saline IV over 10–15min then recheck; if SBP <90, give further 500mL 0.9% saline IV over 10–15min and call ICU/critical care teams.

    • if SBP ≥90, give 1L 0.9% saline IV over 60min

  • Check finger-prick glucose and ketones (dipstick urine for ketones if capillary testing unavailable)

  • Start a fixed rate insulin infusion of 0.1unit/kg/h IV (use 50units human soluble insulin eg Actrapid® in 50mL 0.9% saline; max. rate 15unit/h)

  • Venous blood gas; if pH <7.1 call ICU/critical care team

  • Monitor glucose and ketones hourly, and venous hco3 and K+ at 60min and 2hrly thereafter (Box 10.3); remember K+ will fall unless replaced

  • Further management Endocrinology p. [link]; ECG, CXR, MSU to determine cause

  • Reassess, starting with a, b, c …

Hyperosmolar hyperglycaemic state (HHS)

(Endocrinology p. [link].)

  • 15L/minO2 if SOB or sats <94%

  • Call for senior help

  • Establish venous access, take bloods:

    • fbc, u+e, glucose, osmolality, bld cultures

  • Give 1L 0.9% saline IV over 60min

  • Start IV insulin (fixed rate at 0.05units/kg/h) ONLY if plasma ketones >1mmol/L or 2+ urinary ketones).

  • Monitor u+e and glucose

  • Further management Endocrinology p. [link]; ECG, CXR, MSU to determine cause (Box 10.4)

  • Reassess, starting with a, b, c …

Hyperglycaemia

Think about

► Emergencies

Diabetic ketoacidosis (DKA Endocrinology p. [link]), hyperosmolar hyperglycaemic state (HHS Endocrinology p. [link]);

Common

After sugary food, steroids, non-compliance with diabetic treatment, infection, or acute illness (in diabetics or severely unwell non-diabetics), new diagnosis of DM.

Ask about

‘Osmotic symptoms’ (thirst, polyuria, frequency, urgency), tiredness, weight loss, vomiting, rashes, breathlessness, cough, sputum, chest pain, abdo pain, dysuria;

PMH

dm;

DH

Insulin dose, oral hypoglycaemic dose, medication changes and compliance, steroids;

SH

Alcohol.

Obs

Temp, rr, gcs, urine dip, BM, recent and current blood glucose, fluid balance.

Look for

Volume status (Endocrinology p. [link]), sweet-smelling breath (ketones).

Signs of infection

Check skin thoroughly (including perineum and feet) for abscesses or rashes and injection site problems, look in mouth for dental infection, chest for poor air entry or creps, abdominal tenderness.

Investigations

Finger-prick glucose

(±ketones if available and suspect DKA) repeat if result unexpected;

Urine dipstick

Ketones, evidence of infection (Endocrinology pp. [link][link]);

blds

Send if patient is unwell, has persistent hyperglycaemia (over 48h), or has urinary ketones (type 1 dm), request fbc, u+e, lft, osmolality, pH/hco3 (venous), blood cultures;

ABG

Unnecessary unless concerns regarding respiratory status (venous pH adequate for DKA);

ECG/CXR

If treatment has been required.

Treatment

A single episode of hyperglycaemia in an otherwise well patient is unlikely to suggest underlying pathology. dka takes hours to days to develop while HHS takes days to weeks.

Type 1 diabetes

Check finger-prick glucose (±ketones if available) and urine. Glucose is usually high in dka but may be transiently normal soon after a dose of insulin. Assess volume status (Endocrinology p. [link]), check dipstick for ketonuria and check a venous blood gas for ph/hco3 (normal venous pH or absence of urinary ketones excludes DKA). If hyperglycaemia persistent, try to establish any diurnal pattern and ↑ appropriate insulin doses by 20% with close monitoring of blood glucose.

Type 2 diabetes

Check finger-prick glucose and urine. The glucose must be raised for a diagnosis of HHS. If unwell, follow the treatment plan for HHS initially. Otherwise monitor glucose levels every 6h for 48h, increase oral/IV fluid intake, and reassess. dka can occur in type 2 diabetics who require insulin but it is very unusual (even low levels of residual insulin production inhibit ketogenesis). For persistent hyperglycaemia increase the dose of hypoglycaemic medication or consider starting/increasing insulin with frequent finger-prick glucose checks.

Non-diabetic patients

New diabetics often present with dka/HHS; have a low threshold for starting treatment plans later in this section.

Other triggers

These can include steroids, pregnancy, and stress, eg severe illness or surgery.

Diabetic ketoacidosis (DKA)

(Endocrinology oham4 p. 516.)2

Endocrinology Insulin deficiency resulting in ketosisacidosis and hyperglycaemia → dehydration due to osmotic diuresis. Typically seen following missed insulin treatments or infection in T1DM, or as a first presentation of T1DM.

Diagnose based upon presence of hyperglycaemia (≥11mmol/L), acidosis (venous pH <7.3 or hco3 <15mmol/L), and blood ketones ≥3mmol/L or ketonuria (≥2+). Stabilize the patient as shown Endocrinology p. [link], then:

  • Continue IV insulin infusion and fluid rehydration (see ‘DKA fluids’)

  • Monitor venous K+, pH, and hco3 after 1h, 2h, and then 2hrly using a venous sample on a gas analyser for rapid testing

  • Monitor venous glucose and ketones hourly aiming for blood ketones to fall by >0.5 mmol/L/h and glucose by >3mmol/L/h

  • If patient uses long-acting insulin continue at normal dose/time

  • Continue fixed rate insulin infusion until ketones <0.6mmol/L and pH >7.3. At this point, convert to regular SC insulin if eating and drinking normally, otherwise use a sliding scale (Endocrinology p. [link]). See Box 10.5.

Hyperosmolar hyperglycaemic state (HHS)

(Endocrinology oham4 p. 524.)

Endocrinology Severe, uncorrected hyperglycaemia leads to dehydration, but in the presence of residual insulin production in T2DM, ketoacidosis does not develop. Previously referred to as hyperosmolar non-ketotic state (HONK). Diagnose based upon raised plasma osmolality3(typically >340 mOsmol/kg) with high glucose (typically >30mmol/L).

  • Stabilize the patient as shown on the treatment plan Endocrinology p. [link], then:

  • Continue IV fluid replacement based on clinical state and comorbidities (eg elderly with heart failure)

  • Monitor u+e, glucose and osmolality every 2h. Be aware that hyperglycaemia will drive redistribution of water into the extracellular fluid, lowering serum Na+ concentrations (‘spurious hyponatraemia’)

  • Commence IV insulin (fixed rate 0.05 units/kg/hr) only once glucose has stopped falling with IV fluids alone (unless i blood ketones at diagnosis)

Sliding scales

These allow strict monitoring and control of blood glucose levels. They are used in the treatment of diabetic patients requiring insulin whose oral intake is significantly disrupted (eg NBM, severe vomiting, or serious illness), and in critical illness, where good glycaemic control improves outcomes, eg post MI or on ICU, but are no longer used in the management of DKA or HHS where fixed-rate insulin infusions are advised.

Both the insulin infusion and appropriate IV maintenance fluids are prescribed on the infusions section of the drug card (Fig. 10.1). Use 0.9% saline or 5% glucose (with KCl as necessary), according to the blood glucose (use 0.9% saline if the glucose is running >11mmol/L).


Fig. 10.1 Prescribing insulin and fluids for a sliding scale.

Fig. 10.1 Prescribing insulin and fluids for a sliding scale.

If the patient remains hyperglycaemic despite the sliding scale (Fig. 10.2) then check the infusion pump and cannula; if no problems found, then increase infusion rates by 1.5–2-fold, and check venous pH (T1DM) or osmolality (T2DM). If the capillary blood glucose is <4mmol/L check that there is 5% glucose running, increase the fluid rate and/or glucose concentration (up to 10%); recheck glucose in 30min. If persistently <4mmol/L stop the sliding scale, and restart the infusion at half the doses once blood glucose >6mmol/L. If glucose <2 Endocrinology p. [link].


Fig. 10.2 Example of sliding scale regimen (check local guidelines).

Fig. 10.2 Example of sliding scale regimen (check local guidelines).

Stop a sliding scale

once a patient is eating normally and able to resume normal diabetes medication. Give normal dose of SC insulin 30min before stopping the scale, unless rapid acting (eg Novorapid®, Humalog®) in which case give at same time as stopping the scale.

Prescribing insulin

Most hospitals have separate drug cards for prescribing insulin. Always specify the insulin formulation, and avoid using the abbreviation ‘U’ for units (since this can be misread as a zero). See Fig. 10.3 for an example.


Fig. 10.3 Prescribing subcutaneous insulins.

Fig. 10.3 Prescribing subcutaneous insulins.

Diabetes mellitus

Endocrinology Fasting plasma glucose ≥7.0mmol/L, or ≥11.1mmol/L 2h after a 75g oral glucose load4or HbA1c >48 mmol/mol (on one occasion if symptomatic or 2 occasions in no symptoms).

  • Type 1 Autoimmune pancreatic β‎-cell destruction, resulting in dependence on exogenous insulin; typically presents in children or young adults

  • Type 2 Relative insulin hyposecretion or resistance to effects, requiring drugs to potentiate insulin secretion or effects, or exogenous insulin; typically occurs in adults, especially if overweight

  • Impaired glucose tolerance (IGT) HbA1c 42–47mmol/mol or plasma glucose ≥7.8mmol/ L after OGTT, but <11.1mmol/ L; 20–50% progress to T2DM in 10yr

  • Impaired fasting glucose (IFG) Plasma glucose ≥6.1mmol/L after an overnight fast, but <7.0mmol/L; lower risk of developing T2dm

  • Gestational Any degree of glucose intolerance first detected during pregnancy (Endocrinology p. [link]); around 30% will progress to T2DM within 5yr.

Type 1 DM

(Endocrinology OHCM10 p. 206.)

Symptoms

Tiredness, weight loss, thirst, polyuria, abdo pain, vomiting.

Signs

Sweet-smelling breath, shock, abdominal pain (all suggest DKA).

Investigations

Glucose testing as previously mentioned. Check venous hco3 and pH and urine (ketones) to exclude DKA. If uncertainty about type of diabetes, positive islet cell or glutamic acid decarboxylase antibodies, or low C-peptide levels all suggest T1DM. Check HbA1C (see Box 10.6).

Treatment

Resuscitate and investigate for dka; in the absence of DKA, a new diagnosis of T1DM does not necessitate admission, but the patient should be started on a suitable insulin regimen by an appropriately experienced individual (eg endocrine registrar or diabetes nurse specialist) with regular finger-prick glucose monitoring and prompt out-patient follow-up. For properties of some commonly used insulins Endocrinology p. [link]. Chronic management Endocrinology p. [link]. Involve diabetes team ASAP.

Type 2 DM

(Endocrinology OHCM10 p. 206.)

Symptoms

As for type 1, but can also present with diabetic complications, eg visual problems, neuropathy, mi, CVA, claudication.

Signs

Foot ulcers, infections, peripheral neuropathy, poor visual acuity and retinopathy, evidence of cardiovascular disease.

Investigations

blds

Confirm diagnosis based upon plasma glucose testing ±OGTT (Endocrinology pp. [link][link]), HbA1c (Box 10.6), U+E, lipid profile; ECG.

Treatment

T2DM may initially be controlled by a healthy diet with minimal rapid-release carbohydrates (as found in sugary drinks or sweets) and weight loss. If medication required, uptitrate pharmacological agents (usually to triple therapy) before adding in insulin therapy (Table 10.1). Chronic management Endocrinology p. [link]. See Box 10.7.

Table 10.1 Medications for glycaemic control in T2DM*

Class

Examples

Comment

Biguanides

Metformin

1st line for obese; ↑glucose uptake and ↓appetite; avoid if any renal failure

Sulphonylureas

Gliclazide

Add to metformin (1st line if metformin not suitable); ↑insulin secretion, but causes weight gain. Cautious use in the elderly due to risks of hypoglycaemia

Thiazolidinediones

Pioglitazone

2nd line if other drugs not tolerated or effective; ↓insulin resistance; avoid in heart failure

DPP-4 inhibitors

Sitagliptin

2nd line if other drugs not tolerated or effective; ↑insulin and ↓glucagon secretion

SGLT2 inhibitor

Dapagliflozin

2nd line if other drugs not tolerated or effective; blocks renal reabsorption of glucose and promotes urinary excretion of excess glucose

GLP-1 activators (given SC)

Exenatide, liraglutide

2nd line if other drugs not tolerated or effective, especially if ↑BMI; ↑insulin and ↓glucagon secretion

Insulin

Isophane (given SC)

Added eg if triple oral therapy insufficient (or if metformin not tolerated and dual therapy insufficient)

α‎-glucosidase inhibitors

Acarbose

Rarely used in current practice; ↓carbohydrate absorption; causes flatulence

*For more information, NICE guidelines are available at Endocrinologyguidance.nice.org.uk/CG87

Long-term management of diabetes mellitus

Endocrinology Diabetes mellitus is associated with macrovascular (IHD, CVA, PVD) and microvascular (nephropathy, neuropathy, retinopathy) complications. Large, long-term studies show reductions in complications with control of risk factors; these should be assessed at least annually in a formal review.6,7

Education and lifestyle

Ensure understanding and motivation for glycaemic control (including self-monitoring, medication compliance, and diet as well as assessing risk of hypoglycaemic unawareness). Modify risk factors for complications (physical activity, smoking cessation, foot care). Refer for education classes.

Glycaemic control

Measure HbA1c (every 3–6mth) and adjust therapy accordingly (see Box 10.6); consider revising target if tight control unacceptable to patient based upon individual risk profile.

BP

Aim for BP <140/80 (uncomplicated T2DM) or <135/85 (uncomplicated T1DM); if end-organ damage aim for BP <130/80 (Endocrinology pp. [link][link]). Use an ACEi as 1st line (plus diuretic or Ca2+ channel blocker if African-Caribbean descent).

Lipids

Measure lipid profile and consider cardiovascular risk factors; in all T2DM age >40yr (except those judged to be very low risk) initiate statin therapy (primary prevention—atorvastatin 20mg) and assess response; in T1DM consider statin therapy in those with microalbuminuria, family history, age >35yr, or other high-risk features.

Nephropathy

Test early morning urine albumin:creatinine ratio; if ≥2 repeated measurements show microalbuminuria (♂: >2.5mg/mmol, ♀: >3.5mg/mmol), tighten BP control, initiate ACEi and consider renal referral.

Retinopathy

Arrange annual retinal screening; sudden loss of vision, rubeosis iridis, pre-retinal or vitreous haemorrhage, or retinal detachment require emergency ophthalmology review; new vessel formation requires urgent referral; pre-proliferative retinopathy, significant maculopathy, or unexplained change in visual acuity require routine referral.

Footcare

Assess annually for ulcers, peripheral pulses, sensory function, and foot deformity. If ulcers present, refer urgently to a specialist diabetic footcare team. Those with previous ulcers, absent pulses or impaired sensation require referral to a footcare team for frequent review.8

Neuropathy

Assess for autonomic neuropathy in the form of unexplained vomiting (gastroparesis—consider trial of prokinetic agents, eg metoclopramide), erectile dysfunction (offer phosphodiesterase-5 inhibitor, eg sildenafil), nocturnal diarrhoea, bladder voiding problems, or orthostatic hypotension. Neuropathic pain 9 requires oral neuropathic agent (eg gabapentin, amitriptyline, duloextine). Refractory or severe pain may require opioid analgesia and specialist pain service referral.

Pneumovax® and yearly flu vaccines

These should be offered to all patients.

Pituitary axis

Hypopituitarism

Endocrinology Failure of secretion may affect one or more anterior pituitary hormones.

Causes

Damage to the hypothalamic–pituitary axis after surgery, irradiation, tumours, ischaemia, infection (eg meningitis), or infiltration (eg amyloidosis).

Symptoms and signs

These are specific to each hormone lost, eg growth hormone (GH) loss: weakness, malaise, ↓cardiac output, hypoglycaemia; gonadotrophin (LH, FSH) loss: amenorrhoea, ↓libido, erectile dysfunction; TSH loss: hypothyroidism (Endocrinology pp. [link][link]); ACTH loss: glucocorticoid insufficiency (Endocrinology p. [link]).

Investigations

Tests of pituitary function include LH, FSH, TSH, paired with target organ hormones: testosterone/oestradiol, T4, cortisol and insulin-like growth factor-1 (IGF-1, a marker of growth hormone secretion). Dynamic testing (eg short Synacthen® test Endocrinology p. [link]) is also informative. Generally, testing of pituitary function should be undertaken and interpreted with specialist advice.

Treatment

Identify and treat underlying cause; appropriate hormone replacement may be required eg hydrocortisone (Endocrinology p. [link]) or thyroxine (Endocrinology p. [link]).

►► On the ward, the most important point is to ensure any patient with panhypopituitarism gets regular steroids (increased in acute illness and given IV if necessary) with early endocrinologist involvement (Endocrinologyp. 332).

Diabetes insipidus

Endocrinology Inability to form concentrated urine due to loss of either ADH secretion (neurogenic) or renal response (nephrogenic).

Causes

Neurogenic

idiopathic, brain tumour or metastases, head trauma, cranial surgery;

Nephrogenic

drugs (eg lithium), CRF, post-obstructive uropathy, ↑Ca2+, ↓K+.

Symptoms

Polyuria, thirst (may be extreme).

Signs

Dilute urine, clinically dehydrated (Endocrinology pp. [link][link]).

Investigations

↓urine osmolality (<400mOsmol/kg), ↑plasma osmolality, and ↑Na+. In the water deprivation test (fluid balance, weight, urine, and plasma osmolality recorded over 8h without fluids)—failure to concentrate urine (>600mOsmol/kg) confirms DI. Desmopressin (an Adh analogue) is then given—the production of a concentrated urine at this point implies neurogenic DI; failure to concentrate implies nephrogenic DI.

Treatment

Identify and treat the cause. In neurogenic DI, intranasal desmopressin may be used regularly. In nephrogenic DI, bendroflumethiazide or NSAIDs may be used.

►► Omission of desmopressin in a patient with DI who is unable to drink (eg NBM,↓ GCS) is life-threatening. Pay attention to fluid balance in these patients.

Acromegaly

Endocrinology Hypersecretion of GH from a pituitary tumour drives soft-tissue and skeletal growth resulting in characteristic facial and body features.

Symptoms and signs

Enlarged hands and feet, coarse facial features, prognathism, macroglossia; headache ±bitemporal hemianopia. Sweating, hypertension, and hyperglycaemia are markers of disease activity.

Investigations

IGF-1 levels reflect GH secretion; OGTT and other tests of pituitary function under specialist guidance; pituitary MRI.

Treatment

Transsphenoidal resection of pituitary tumour where possible; medical therapy includes somatostatin analogues (eg octreotide).

Adrenal disease

Cushing’s syndrome

(Endocrinology OHCM10 p. 224.)

Endocrinology Excess of glucocorticoids (eg cortisol); ‘Cushing’s disease’ when due to an ACTH-producing pituitary tumour. ACTH may also be produced ectopically, eg by small-cell lung cancers. Adrenal adenomas or carcinomas are ACTH-independent causes (and will suppress ACTH). A patient on steroids may become ‘Cushingoid’.

Symptoms

Weight gain, depression, psychosis, tiredness, weakness, oligo- or amenorrhoea, hirsutism, impotence, infections, dm.

Signs

Central obesity (buffalo hump), moon-face, water retention, ↑bp, thin skin, striae, bruising, peripheral wasting; hyperpigmentation only in Cushing’s disease or ectopic acth production.

Investigations

↑glucose, ↑24h urinary cortisol, plasma acth and 8am cortisol, dexamethasone suppression tests (Endocrinology OHCM10 p. 225); imaging tests are problematic due to high rates of ‘incidentalomas’ on adrenal CT or pituitary MRI and are only done after biochemical confirmation of the diagnosis.

Treatment

Localize and remove source of cortisol, eg transsphenoidal resection of pituitary adenoma, adrenalectomy for adrenal adenoma. If surgical treatment fails or unsuitable (eg ectopic ACTH from metastatic lung cancer), suppress steroidogenesis, eg with ketoconazole or metyrapone. If iatrogenic cause, try to taper steroid dose (Endocrinology p. [link]). Consider bone protection with bisphosphonate and vitamin D; monitor for ↑glucose.

Complications

Osteoporosis, dm, infection, poor healing, infertility.

Adrenal insufficiency

(Endocrinology OHCM10 p. 226.)

Endocrinology Adrenal deficiency, typically seen upon abrupt withdrawal of long-term steroid therapy; 1° adrenal (Addison’s) disease includes autoimmune (commonest in UK), TB (commonest worldwide), metastases (eg lung, breast), Waterhouse–Friderichsen syndrome (sepsis and adrenal haemorrhage).

Symptoms

Tiredness, lethargy, weight loss, weakness, dizziness, depression, abdo pain, diarrhoea or constipation, vomiting, myalgia.

Signs

Vitiligo, postural hypotension, hyperpigmentation of creases, scars, and mouth (buccal).

Investigations

↓Na+, ↑K+, ↑urea, may have abnormal fbc and lft. If suspected perform short Synacthen® test: order 250micrograms Synacthen® from pharmacy, once this arrives send a blood sample for cortisol and ACTH levels, give the Synacthen® im/IV (Endocrinology p. [link]); repeat cortisol levels in 30min. Addison’s is excluded if initial, or 30min cortisol is >550nmol/L.

Treatment

Hydrocortisone 20–30 mg/day in divided doses to mimic normal circadian rhythm. May also need fludrocortisone (50–200micrograms PO OD) if electrolytes deranged or postural hypotension. ► If unwell, double dose of oral steroids for during of illness. If vomiting, needs IV/IM hydrocortisone—100mg stat and seek medical attention.

► Addisonian crisis

Shock, ↓gcs, or hypoglycaemia in a patient with Addison’s disease or stopping long-term steroid therapy. Resuscitate according to Endocrinology pp. [link][link], send bloods for cortisol levels, and give hydrocortisone (200mg IV STAT, then 100mg IV/8h) and broad-spectrum antibiotics (eg Tazocin® 4.5g iv); seek urgent endocrinologist advice.

Hyperaldosteronism

(Endocrinology OHCM10 p. 228.)

Endocrinology Excess aldosterone secretion, resulting in Na+ and water retention; typically from an adrenal adenoma (Conn’s syndrome), or adrenal hyperplasia.

Symptoms

Thirst, polyuria, weakness, muscle spasms, headaches.

Signs

Hypertension (especially if refractory to multiple antihypertensive agents or young age of onset).

Investigations

↓K+, normal or ↑Na+, metabolic alkalosis; measure plasma renin and aldosterone together after 30min supine (postural changes affect renin secretion). Ideally the patient should be off all antihypertensives apart from α‎-blockers. ↑Aldosterone with ↓renin supports the diagnosis; consider CT abdo (but beware ‘incidentalomas’: abnormal CT findings, such as a small adrenal mass of no clinical significance).

Treatment

Spironolactone; if adenoma, surgical resection may be attempted after 4wk medical therapy once electrolytes and BP controlled.

Secondary hyperaldosteronism

This occurs when renal perfusion is decreased, leading to high renin secretion. Common causes include diuretics, heart failure, liver failure, and renal artery stenosis. Features are similar, but aldosterone:renin ratio will not be high. Manage with spironolactone or acei.

Phaeochromocytoma

(Endocrinology OHCM10 p. 228.)

Endocrinology Catecholamine (eg noradrenaline) production from tumours with in the adrenal medulla, or more rarely extra-adrenal source. Consider in those with drug-resistant or young-onset hypertension, or typical symptoms.

Symptoms

Episodic anxiety, sweating, facial flushing, chest tightness, breathlessness, tremor, palpitations, headaches, abdo pain, vomiting, or diarrhoea.

Signs

Episodic hypertension.

Investigations

Plasma and urine (24h collection) metanephrines. Imaging if biochemistry positive.

Treatment

Surgical resection of tumour can safely be performed only after adrenoreceptor blockade. α‎-blockers (eg phenoxybenzamine) are given prior to β‎-blockers (eg propranolol) to avoid hypertensive crisis of unopposed α‎-adrenoreceptor stimulation. See Box 10.8.

Thyroid disease

Hyperthyroidism

Endocrinology Hypermetabolic state driven by excess thyroxine.

Causes

Graves’ disease (50–60%; agonistic autoantibodies to TSH receptor), toxic multinodular goitre (15–20%), subacute thyroiditis (15%; self-limiting, with painful granulomatous infiltrates as de Quervain’s thyroiditis, or painless lymphocytic infiltrates), toxic adenoma (5%), amiodarone (either due to excess iodine or drug induced thyroiditis), excess exogenous replacement.

Symptoms

Weight loss, agitation, anxiety, psychosis, sweating, heat intolerance, diarrhoea, tremor, oligomenorrhoea.

Signs

Thin, ↑hr, irregular pulse, warm hands, tremor, goitre ±nodules, lid lag, lid retraction, muscle weakness;

Specific to Graves’ disease

Exophthalmos, ophthalmoplegia, pretibial myxoedema, thyroid acropachy.

Investigations

TSH used as screening test—if ↓ then measure fT4 (free thyroxine, ie active, not bound to plasma proteins); antithyroid peroxidase (TPO) antibodies positive in Graves’ and other forms of thyroiditis (TSH receptor antibodies more specific for Graves’ but not routinely measured);

ECG

to exclude af;

USS

Thyroid, or nuclear scintigraphy may help localize lesion and assess uptake.

Treatment

Symptom relief with propranolol 40mg/6h (or rate limiting calcium channel blocker if asthmatic); suppress thyroid function using carbimazole in dose titrated to TFTs, or with thyroxine in ‘block and replace’ approach. Other options include radioiodine ablation or surgical resection.

Complications

CCF, AF, ophthalmopathy, osteoporosis.

►► Thyrotoxic storm

This is caused by infection, severe illness, recent thyroid surgery or radioiodine. Tachycardia, ±af, fever, agitation, confusion, or coma with ↑fT4 or ↑T3. Resuscitate as required (Endocrinology pp. [link][link]) and get senior help. Propranolol (suppresses sympathetic response, blocks T4 to T3 conversion and alleviates symptoms), propylthiouracil (inhibits T3/T4 production and T4 to T3 conversion and hydrocortisone (reduces iodine uptake and inhibits T4 to T3 conversion) are the main treatments. Carbimazole (inhibits T3/T4 production) has a slower onset of action but may be preferred to propylthiouracil since it has a longer duration of action and is less hepatotoxic.

Hypothyroidism

Endocrinology Common and insidious; characterized by insufficient thyroxine release (see Box 10.9).

Causes

Hashimoto’s thyroiditis (autoimmune destruction), resolution stage of subacute thyroiditis, drugs (eg amiodarone, lithium), iatrogenic (post surgery or radioiodine), iodine deficiency (commonest worldwide). See also Box 10.10.

Symptoms

Fatigue, lethargy, weight gain, hair loss, depression, confusion, dementia, cold intolerance, constipation, menorrhagia, infertility.

Signs

Obese, bradycardia, ↓temp, cold/dry hands, macroglossia, jaundice, pitting oedema, goitre, peripheral neuropathy, slow relaxing reflexes.

Investigations

↑TSH, ↓fT4; +ve thyroid autoantibodies.

Treatment

Levothyroxine (T4): 50micrograms/24h PO, gradually titrated up into range 50–150micrograms/24h based upon monthly TFTs until TSH in normal range; yearly tft once stable. Beware of worsening underlying ischaemic heart disease: consider propranolol 40mg/6h PO to prevent ↑HR.

Complications

Angina from treatment, myxoedema coma.

Notes:

1 Loss of early autonomic symptoms warning of mild hypoglycaemia (eg tremor, sweating) seen in those with longstanding DM and frequent hypoglycaemic episodes.

3 Plasma osmolality may be estimated as 2×([Na+] + [K+])+ urea + glucose while awaiting a formal lab measurement.

4 In the presence of diabetes symptoms, a random plasma glucose ≥11.1mmol/L may be considered diagnostic; in the absence of symptoms, all tests should be repeated on a separate occasion.

5 Ie ≈6.5% (48mmol/mol) and ≈7.5% (58mmol/mol). Since 2009 HbA1c levels have been reported by NHS labs as mmol per mol (of haemoglobin without glucose attached) but previous units of % were reported in key trials, used in guidelines and still permeate the consciousness of some older patients and clinicians.

6 For NICE guidelines on management of T1DM see Endocrinologyguidance.nice.org.uk/NG17

7 For NICE guidelines on management of T2DM, see Endocrinologyguidance.nice.org.uk/NG28

8 For NICE guidelines on footcare in T2DM, see Endocrinologyguidance.nice.org.uk/NG19

9 For NICE guidelines on neuropathic pain, see Endocrinologyguidance.nice.org.uk/CG173