Weak and vomiting: an endocrine emergency

aka Pediatric Perplexity 012

A 6 year-old boy presents to the emergency department after 5 days of vomiting. He was initially seen by his family doctor and treated for gastroenteritis. However, his vomiting has persisted and he is lethargic and no longer able to walk. He has no history of fevers, abdominal pain or diarrhoea. He was previously well with no significant past medical history or medications.

His vital signs are T36.4C, P 120/min, BP 95/60mmHg, R24/min and SpO2 99%OA. He is drowsy and generally weak with no focal neurological deficits, and is able to protect his own airway. He has dry mucus membranes and his eyes appear sunken though his capillary refill time is <2 seconds.

Questions

Q1. What is your immediate management priority?

Check the blood glucose.

Although the patient looks dry and will need fluid replacement, his ABCs are stable at present. The main concern is his altered mental state — we need to check his blood glucose ASAP.

Sure enough, his fingerprick blood glucose is 1.9 mmol/L. He is immediately treated with 2mL/kg of 25% glucose IV.

Blood tests were taken on arrival. Of note are the following:

Sodium 117 mmol/L (135-145 mmol/L)
Potassium 6.1 mmol/L (3-5 mmol/L)
Urea 17.1 mmol/L (3-7 mmol/L)
Creatine 111 umol/L (50-90 umol/L)

Q2. based on the laboratory data and the clinical information, what diagnosis must be suspected?

Acute adrenal insufficiency

The manifestations of adrenal insufficiency are:

  • glucocorticoid deficiency —
    anorexia, vomiting, weakness, hypoglycemia, hypotension (especially postural), shock
  • mineralocorticoid deficiency —
    dehydration, hyponatremia, hyperkalemia, acidosis, pre-renal impairment

The presence of features of both glucocorticoid and mineralocorticoid deficiency in this patient make it likely that this patient has primary adrenal insufficiency (see Q3).

Hypotension is not always seen in adrenal insufficiency, but postural changes may go undetected unless they are specifically assessed. However, hypotension or shock out of proportion to the severity of the current illness is the key feature of adrenal crisis.

Other points:

  • Adrenal insufficiency is part of the differential diagnosis for normal anion-gap metabolic acidosis (NAGMA).
  • The skin may be hyperpigmented in non-sun exposed regions. This suggests a primary cause of adrenal insufficiency, as it results from elevated ACTH levels.
  • Features of androgen deficiency may also be seen, especially in women.
  • All that vomits is NOT gastroenteritis!

Q3. What are the possible underlying causes of this condition?

Adrenal insufficiency is most commonly seen in patients on steroids who have an inter-current illness or physiological stress, or have their steroids withdrawn. However, this child had no previous medical problems and was not taking steroids.

Adrenal insufficiency can be primary or secondary, each with acute or chronic causes.

In primary adrenal insufficiency there is failure of adrenal gland to produce cortisol and aldosterone. Secondary adrenal insufficiency is characterised by failure of the pituitary to produce ACTH, resulting in cortisol deficiency only — aldosterone is still produced because it is regulated by the still intact renin-angiotensin-aldosterone system.

Primary adrenal insufficiency:

  • acute —
    Adrenal hemorrhage — meningococcemia (Waterhouse-Friderichsen syndrome) and other sepsis, anticoagulation, anticardiolipin antibody syndrome, trauma
  • chronic —
    Autoimmune adrenalitis (Addison’s disease) — isolated or polyglandular deficiency, HIV infection (direct involvement)
    TB and disseminated infections as seen in AIDS
    Metastatic cancer (breast, lung)
    Infiltrative diseases (e.g. sarcoid, hemochromatosis, amyloid)
    Congenital (e.g. adrenal hypoplasia, adrenoleukodystrophy, ACTH resistance)
    Bilateral adrenalectomy
    Drugs (e.g. etomidate, ketoconazole, rifampicin)

Secondary adrenal insufficiency:

  • acute —
    Pituitary apoplexy (hemorrhage into a pituitary tumor)
    Postpartum pituitary necrosis (Sheehan’s syndrome)
    Traumatic brain injury
    Relative adrenal insufficiency — e.g. sepsis, hepatic failure, severe acute pancreatitis, trauma
  • chronic —
    Chronic steroid use with functional deficiency
    Pituitary tumor (primary or metastatic)
    Pituitary surgery or irradiation
    Infiltrative (e.g. sarcoid, eosinophilic granuloma, TB)
    Traumatic brain injury
    Postpartum pituitary necrosis (Sheehan’s syndrome)
    Empty sella syndrome

Acute presentations may have an underlying chronic cause with an acute precipitating event. About 90% of the adrenals must be destroyed before function is affected.

An inherited disorder such as polyglandular deficiency syndromes, adrenoleukodystrophy, adrenal hypoplasia, or ACTH unresponsiveness should be suspected in childhood presentations of adrenal insufficiency.

Q4. What investigations are required?

The important initial investigations are:

  • Laboratory —
    glucose, UEC, blood gas
    collect a tube of clotted blood for hormone levels; especially cortisol
  • ECG if K > 6mmol/L to check for ECG manifestations of hyperkalemia

A cortisol level taken at the time of presentation during acute adrenal insufficiency can be used (unlike the in the chronic setting, when a level should be taken between 6 and 8 am). If this random cortisol is non-diagnostic (a mid-range level), an ACTH (cosyntropin) stimulation test is  required to confirm adrenal insufficiency.

Do not delay treatment while awaiting the result of these tests!

The following tests help distinguish between primary and secondary adrenal insufficiency:

  • ACTH — elevated in primary causes, normal or decreased in secondary causes.
  • renin and aldosterone — normal in secondary causes, whereas in primary adrenal insufficiency renin is high and aldosterone is low.

Further investigations may be required to identify the underlying cause, e.g. CT abdomen, CT/MRI brain, adrenal autoantibodies, other hormone levels, etc.

Q5. Describe the acute management of this condition.

Management of acute adrenal insufficiency:

  • Attend to ABCs
  • Treat shock if present —
    e.g. 20 mL/kg boluses of normal saline until capillary refill time <2 seconds.
  • Detect and correct hypoglycemia —
    e.g. 5mL/kg 10% dextrose in infants, 2mL/kg 25% glucose in older children
  • Treat hyperkalemia
  • Administer steroids —
    hydrocortisone IV
    can be given IM initially if there is a delay in obtaining IV access
    typical doses according to age:
    <1y: 25 mg q6h, 1-3y: 25-50mg q6h, 4-14y: 50-75mg q6h, 15+y: 100mg q6h.
  • IV fluid administration —
    add fluid deficit to maintenance requirements and replace over 24 hours
    [fluid deficit (mL) = %dehydration x wt(kg) x 10]
    use 0.9% NaCL with 5% glucose
    [use 0.45% NaCl if Na>130 mmol/L; use 10% dextrose if needed for ongoing hypoglycemia]
  • seek and treat precipitating causes (e.g. sepsis)
  • refer to the endocrinology team for admission. HDU/ ICU admission is often appropriate for regular monitoring of fluid status and electrolytes.

Hydrocortisone is changed to an oral dose and the dose is gradually reduced once the patient is stable (typical maintenance dose is 10-15 mg/m2/d).

In patients with mineralocorticoid deficiency, fludrocortisone (e.g. 0.1mg) is usually started as soon as the patient can tolerate oral fluids. Fludrocortisone is not required acutely because hydrocortisone has both glucocorticoid and mineralocorticoid activity.

References

  • Arlt W. The approach to the adult with newly diagnosed adrenal insufficiency. J Clin Endocrinol Metab. 2009 Apr;94(4):1059-67. PMID: 19349469.
  • Arlt W, Allolio B. Adrenal insufficiency. Lancet. 2003 May 31;361(9372):1881-93. PMID: 12788587.
  • Marx JA, Hockberger R, Walls RM. Rosen’s Emergency Medicine: Concepts and Clinical Practice (7th edition), Mosby 2009. [mdconsult.com]
  • Royal Children’s Hospital Melbourne. Paediatric Handbook (8th edition), Wiley-Blackwell 2010. [website]
  • Royal Children’s Hospital Melbourne. RCH Clinical Practice Guidelines.
  • Jung C, Inder WJ. Management of adrenal insufficiency during the stress of medical illness and surgery. Med J Aust. 2008 Apr 7;188(7):409-13. Review. PMID: 18393745.

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