Bartter's and Gitelman's Syndromes

Bartter's and Gitelman's Syndromes in MRCP

I hate syndromes because I always can't remember them well. My Professor once said, clinicians term something as syndrome when they do not know much about an illness.

Having said that, some syndromes are important for your MRCP,I am going to talk about Bartter's and Gitelman's syndrome.

First fact to remember, Bartter's syndrome is an disorder of transport in the medullary thick ascending limb of Henle.

Second fact to remember, Bartter's syndrome is an illness resembles patients chronically takingloop diuretcs that inhibit activity of Na-K-2Cl co transporter.

Third fact to remember- they do not have hypertension.

So, what will happen to you if you chronically take frusemide?

Easy- you get hypokalemia and alkalosis and hypercalciuria- therefore leading to nephrocalcinosis. You might not be able to explain hypercalciuria but just remember that. Therefore, patients with Bartter's syndrome get hypokalemic metabolic alkalosis. ( as compared to hypokalemic metabolic acidosis in Renal tubular acidosis)

If you are interested to read more about ROMK ( renal outer medullary potassium channel), try to search the net! ( not important in your MRCP!)

As for Gitelman's syndrome, it is an disorder of distal convulated tubule, it is an variant of Bartter's syndome with similar biochemical abnormalities except Gitelman's syndrome has hypocalciuria as compared to hypercalciuria in Bartter's syndrome and hypomagnesimia in Gitelman's syndrome. ( Bartter's syndrome has normal Magnesium Level)

MRCP Past Year Question

A 15-year-old girl is referred to clinic complaining of generalised muscle weakness, fatigue and polyuria. Her blood pressure in clinic is measured at 90/74 mmHg. Investigations:

Serum sodium 127 mmol/l
Serum potassium 3.0 mmol/l
Serum urea 7.2 mmol/l
Serum creatinine 110 umol/l
Serum chloride 92 mmol/l (NR 97-108 mmol/l)
Serum bicarbonate 34 mmol/l (NR 22-28 mmol/l)
82 mmol/l (NR 0.8-1.1 mmol/l)
Urine sodium 160 mmol/l (NR 40-130 mmol/l)
Urine calcium 8.0 mmol/24hr (NR 2.5-8.0 mmol/24hr)
Which of the following is the most likely diagnosis?
Available marks are shown in brackets

1 ) Addison's disease
2 ) Bartter's syndrome
3 ) Laxative abuse
4 ) Liddle's syndrome
5 ) Thiazide diuretic abuse

What is the answer??