Conn’s syndrome with a focus on a unilateral adrenal gland

HOSP # Mrs DW WARD Endocrine Department – CathLab – UCT private Hospital
CONSULTANT   Dr Jody Rusch DOB/AGE 49y Female

Abnormal Result

49yr old female

Presenting Complaint

Medical complaint: Suspected Conn’s disease – right adrenal lesion/ irregular left adrenal gland

History

Past Medical History: Resistant Hypertension, primary hyperaldosteronism (confirmed previously with saline infusion test), hypokalaemia, hypercholesterolaemia, newly diagnosed DM.

Family History: Hypertension – Mother.

Past Surgical History: TAH – 7 years ago.

Allergies: Nil known

Smoker

Meds: Amlodipine/Valsartan 10/320 daily, Doxazosin 8mg daily, Furosemide 40mg daily, Spironolactone 25mg daily, Carvedilol 25mg daily, Metformin 1g nocte, Simvastatin 20mg nocte, Zolpidem 10mg nocte.

Examination

Not available

Laboratory Investigations

Other Investigations

Not available for this patient.

Ideally one would need a CT with contrast beforehand to adequately visualize the positions of the adrenal veins, as this may aid in the canulation, especially of the right adrenal vein.

One needs to diagnose hyperaldosteronism (by an appropriate salt loading test) before proceeding to bilateral adrenal vein sampling.

Final Diagnosis

Interpretation

Definition Formula Clinical significance
Selectivity index PCC(side) / PCC (ivc) >cutoff confirms canulation of adrenal vein
>3 stimulated
>2 unstimulated
Lateralization index PAC/PCC (dom) : PAC/PCC (non-dom) >cutoff confirms laterilization of hyperaldo secretion
>4 stimulated
>2 unstimulated
Contralateral suppression index PAC/PCC (non-dom) : PAC/PCC (ivc) <cutoff indicate ipsilateral suppression
and suggest contralateral
aldosterone overproduction.
Table 1 – Interpretation of bilateral adrenal vein sampling.
PCC: plasma cortisol concentration, PAC: plasma aldosterone concentration, ivc: inferior vena cava or peripheral vein, dom: dominant side, non-dom: non-dominant side.

Selectivity index

Right: 0.2 (mean)

Left: 2.8 (mean)

These two results indicate that the left adrenal has likely been canulated adequately, but the right vein inadequately.

Lateralization index

Unable to comment because of the inadequate canulation of the right adrenal vein. If determined, it would very likely provide a false result.

Contralateral suppression index

616.8 /1260.25 : 2540/3609

= 0.70

This falls in between some of the referenced cutoffs (<1 and <0.5)

All of the other samples also fall somewhere in this range. Biochemically, these results suggests inadequate right sided venous sampling (a commonly described problem)

Take Home Message

  • Procedure is done in the Cath Lab
  • The patient received continuous synacthen infusion
  • Done under imaging with contrast used for the localisation of the adrenal gland and adrenal vein
  • Sequential sampling technique used, generally > 20 mins infusion
  • Multi-disciplinary: nurses, anaesthetist, radiographer, intervention radiologists, students, chemical pathologists
  • Difficulty with sampling right side for both patients
  • Difficulty with interpreting results – most likely due to inadequate canulation of the right adrenal vein

Some important learning points

  1. Adrenal vein sampling may be a valuable tool that is underutilised
  2. Careful selection of patients essential – also patient should consent to surgical removal of the affected adrenal before this invasive procedure is initiated
  3. Inter-disciplinary approach is necessary
  4. Obtaining cosyntroponin (aka synacthen) can be difficult (Section 21), but recommended
  5. Right adrenal access difficult: may require specific imaging. Recommended to start on the right or do simulataneous sampling
  6. Adrenalectomy may be curative or help achieve better control of BP thus decrease associated morbidity and mortality in those with unilateral adenoma


ACTH

HOSP # WARD G16 Medical Ward
CONSULTANT   DOB/AGE 54 y Female

Abnormal Result

21/08/2018 Two ACTH tests (referred to another laboratory) and two
Cortisol levels (at our laboratory) were done. 
At first it was thought to be a dexamethasone suppression test, but then
realized the clinicians were suspecting hypopituitarism.

10h05: ACTH 0.7 pmol/L ↓ (1.6-13.9)  Cortisol  8 nmol/L ↓  (Morning: 133- 537; Afternoon 68 – 327)

10h35: ACTH 1.8 pmol/L N (1.6-13.9) 
Cortisol  68 nmol/L ↓  (Morning: 133- 537; Afternoon 68 – 327)

Presenting Complaint

? hypopituitarism

History

Known with a pituitary macroadenoma, previously seen at the Radiotherapy clinic in 2016.

Examination

No clinical info available.

For Primary adrenal insufficiency one would expect: Hyperpigmentation
(due to ↑ ACTH), +/- hyperkalemia/hyponatremia (aldosterone effect), +/-
virilization.

For Secondary adrenal insufficiency there is subtle symptoms, electrolytes are not deranged significantly because aldosterone function is preserved. See table on Bishop 7th ed. p. 459.

Laboratory Investigations

Measurement of
plasma ACTH concentration is used to assess Cushing’s disease, adrenal tumors,
ectopic ACTH-producing tumors, Addison’s disease, Nelson’s syndrome, and
hypopituitarism.

The
laboratory diagnosis of hypopituitarism, however is relatively straightforward.
In contrast to the primary failure of an endocrine gland that is accompanied by
dramatic increases in circulating levels of the corresponding pituitary tropic
hormone, secondary failure (hypopituitarism) is associated with low or normal
levels of tropic hormone.  This is the
diagnosis in this case with the history of previous radiotherapy which was
given for a macro-adenoma.

Other Investigations

Free T4 on 19/04/2018 was 7.8 pmol/L (12-22), also suggesting possible hypopituitarism, although a TSH would be helpful.

Final Diagnosis

Hypopituitarism confirmed.

Take Home Messages

Dexamethasone suppression test need only measurement of cortisol, not accompanying ACTH, except in extended work-up however, where a Cosyntropin (CRH) stimulation test can be done to distinguish between pituitary or hypothalamic insufficiency.

Evaluation of pituitary function need the Primary hormone (Cortisol) as well as the tropic hormones from the pituitary (ACTH).