Hyperaldosteronism

HOSP # WARD Murraysburg Hospital, Female Ward
CONSULTANT   DOB/AGE 51 y female

Abnormal Result

Aldosterone: 1380 pmol/L

Renin: 2.1 ng/L

Aldosterone: Renin ratio: 657.14 pmol/ng

Presenting Complaint

Uncontrolled Hypertension, unresolved on maximum dose of 3 antihypertensives.

History

Examination

Laboratory Investigations

Other Investigations

Urine electrolytes

Serum Results

Date Sodium mmol/L Potassium mmol/L eGFR ml/min GGT U/L Chol mmol/L TSH mIU/L T4 pmol/L FreeT3 pmol/L Cort nmol/L
21/04/2015          2,8   >60           5,07                              
30/11/2015          3,8     >60           4,53                              
15/11/2016          >60           4,04                              
20/03/2017                 >60           4,36                              
05/06/2018   144  3,4    56           4,39    1,79    11,9       5     394  
20/08/2018   131 4,6    42                                            
21/08/2018                                                               
24/08/2018                                                               
26/08/2018                                                               
26/08/2018                                                               
26/09/2019   139   2,4    45                  0.81                       
27/09/2019   142   2,6    43                                            
01/10/2019                                                               
02/10/2019   139   2,9    40                 CEGK                
03/10/2019                                                               
07/10/2019   138   3,9      38                                            
31/10/2019   139   1,9    30      28                                     

Urine metanephrines

Urine collection period 24  h       Reference value
Urine volume 3080 ml       
Ucreat   2,2 mmol/L       
Umetadren   160 nmol/L       
Unormetadren   870  nmol/L
dUmetadren   493  nmol/24h 152-913
dUnormetadren  2680 nmol/24h 699-2643
Umetadren:cr    73  nmol/mmol creat 17-91
Unormetad:cr   395 nmol/mmol creat 75-309

Final Diagnosis

Primary hyperaldosteronism causing secondary hypertension with accompanying renal injury.

Take Home Messages

Reference Ranges for Aldosterone:

  • Upright 70 – 1066 pmol/L
  • Supine 49 – 643 pmol/L

Screening for primary hyperaldosteronism: most sensitive when >350 pmol/L

Reference Ranges for Renin:

  • Upright: 2.7 – 27.7 ng/L
  • Supine: 1.7 – 23.9 ng/L

Beta-blockers suppress renin levels and should be stopped 2 weeks before testing.

Aldosterone: Renin Ratio:

Most sensitive when the ratio is >118 pmol/ng.

Effects of hyperaldosteronism

  • One’s expectation is a high serum sodium, but since it normalizes with an increase in fluid volume, hence hypertension as in this case, there is normal sodium.
  • Low serum potassium due to loss in urine, although this can also be normal.
  • Increased urine potassium concentration (>30 mmol/L) in a random urine specimen suggests increased mineralocorticoid effect.
  • The renin:aldosterone ratio is used to compensate for the increase in aldosterone which is caused by an increase in renin (for instance which is caused by hypovolemia or low blood pressure).
  • Some studies recently published are suggesting that the prevalence of hyperaldosteronism are significantly more than was (and is) thought, and hence urinary (24 hour) aldosterone measurement may be more accurate to screen for hyperaldosteronism. The authors of recent estimates of the prevalence of hyperaldosteronism are of opinion that hyperaldosteronism may be the cause of around 10% of unexplained “essential” hypertensives (see attached articles).
Hyperaldo-prevalence-2020Download
Primary-hyperaldo-Editorial-2020Download


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).