EURASIAN JOURNAL OF

FAMILY MEDICINE

AVRASYA AİLE HEKİMLİĞİ DERGİSİ

Total Visitors : 104,573

 

Archive


Quiz: What Is Your Diagnosis?
Tanınız Nedir?
Bahriye Bahar Yücel, Dilek Toprak

 

How to cite / Atıf için: Yucel BB, Toprak D. Quiz: What Is Your Diagnosis? Euras J Fam Med 2016;5(1):53-6

 

Quiz


A 25 years old woman presented to the emergency department with complaints of numbness and muscle contractions in her hands. Her initial examination revealed hypocalcemia (Ca=7.7 mg/dL) and hypokalemia (K=2.7 mg/dL) so, she was treated  with potassium and calcium supplements. The patient’s control biochemistry results showed the continued hypocalcemia and hypokalemia. The physical examination revealed blood pressure of 110/70 mmHg, pulse 72/min, respiratory rate of 20/min, the existence of numbness in both hands and arms and spasm in hands. Chovestek and Trousseau signs were positive and other system examinations were unremarkable. Hemogram was normal; according to the biochemistry results, her blood urea nitrogen was (BUN) 20 mg/dL, creatinine 0.6 mg/dL, sodium 143 mmol/L, potassium 3.1 mmol/L, chloride 96 mmol/L, 8.1 mg calcium/dL, magnesium 0.8 mg/dL. 

Urine analysis results were normal. Her 24 hour urine test results were as follows; sodium 285.66 mmol/day, potassium 45.202 mmol/day, chlorine 270.204 mmol/day, calcium 23.3 mg/day,  phosphorus 256.3 mg/day and  magnesium 19.596 mg/day.  

Venous blood gas analysis results were as following; pH: 7.428, partial pressure of oxygen (PO2): 29 mmHg, carbon monoxide partial pressure (pCO2): 48.3 mmHg, bicarbonate (HCO3): 31.3 mmol/L, and oxygen saturation (SaO2): 52% which was thought as metabolic alcalosis. Patient’s  thyroid stimulating hormone (TSH), free T4, free T3, parathyroid hormone (PTH) and serum basal cortisol levels were normal. 

In abdominal ultrasonography, a double collecting system view of the left kidney was observed, but no nephrolithiasis or ectasia was detected. 

Her electrocardiogram showed normal sinus rhythm and normal QT interval. Her plasma renin activity (132 ng/L), and aldosterone level (334 pg/ml) was measured while she was lying. There was no medication usage history such as diuretics and laxatives.

QUESTION

What is your diagnosis based on the patient's symptoms and history?
A. Bulimia nervosa
B. Gitelman syndrome
C. The use of diuretics (addiction)
D. Bartter syndrome
E. Excessive use of laxatives drugs


ANSWER: B (Gitelman Syndrome)

Gitelman Syndrome is an autosomal recessive disorder, characterized by hypokalemia and metabolic alkalosis with outgoing hypocalciuria and hypomagnesemia. This syndrome is usually diagnosed during adulthood. The disease is caused by mutations in the SLC12A3 gene that encodes the thiazide- sensitive Na/Cl co-transporter found in the distal convoluted tubules of the kidneys. Na/Cl cotransporter system is inactivated and this situation leads to loss of sodium and chloride. Ultimately, hypovolemia and metabolic alkalosis develop in patients. Hypovolemia cause the renin-angiotensin-aldosterone system to be activated which increase the sodium load in the cortical collecting duct. Also, it causes hypokalemia and metabolic alkalosis by increasing the potassium and hydrogen excretion. Prostaglandin excretion in the urine is normal in patients with Gitelman syndrome. They have normal blood pressure. Although patients have hypocalcemia, no changes are detected in serum calcium, phosphorus, PTH and vitamin D3 levels. Besides the correction of hypomagnesemia and potassium supplementation, potassium-sparing diuretics are also used in the treatment such as amiloride, triamterene and spironolactone. ACE inhibitors can also be used to control hypokalemia. Unlike Bartter syndrome, non-steroidal anti-inflammatory drugs are not useful since, the prostaglandin levels are normal.

Bartter Syndrome is transmitted as an autosomal recessive trait. Basic disorder is a defect in sodium reabsorption in the thick segments of Henle. While (ROMK) mutation is in the Na-K-2Cl cotransporter in some form of the disease, there is mutation in the basolateral chloride channel and outer medulla of rat potassium channel in some of the other forms. Absorption of calcium and magnesium is blocked in the thick ascending limb as a result of all these defects. Since some portion of the magnesium is reabsorbed in the distal convoluted tubule, magnesium loss is reduced. This syndrome is usually diagnosed in the first years of life. Polyhydroamnios and prematurity are common. Polyuria, polydipsia, hiperprostoglandinüria, dehydration, muscle weakness, tetany, paresthesia and nephrocalcinosis are also detected in the patients suffering from Bartter syndrome. Joint pain, low-normal blood pressure and convulsions may occur due to chondrocalcinosis. Moreover, hyponatremia, hypocalcemia, hypercalciuria, hyperaldosteronism and secondary developed hypokalemic and metabolic alkalosis are detected. Growth retardation is observed in patients not receiving adequate treatment. It has been reported that psychomotor and somatic growth is normal for the patients under treatment. The presence of hypocalciuria and hypomagnesemia, normal prostaglandin E2 excretion in the urine even the increase in serum renin activity and the observation of a prolonged QT interval differ the Gitelman Syndrome from the Bartter Syndrome. Suppression of the increased synthesis of PGE2 in the kidney plays a key role in the treatment. Used for this purpose, indomethacin which is a non-steroidal antiinflammatory agent, is the first option in the treatment. Clinical and laboratory improvement are seen in a large number of patients by the use of indomethacin in effective dose without the need of an additional potassium support or RAAS blockade. If hypokalemia persist despite an adequate treatment with prostaglandin inhibitors, angiotensin-converting enzyme blockers, angiotensin receptor blockers or direct renin inhibitors can be used  in order to ensure the RAAS blockade with ongoing monitoring of the blood pressure and renal functions. 

Diuretic or laxative abuse, depression, other psychiatric problems and can be detected by a complete medical history evaluation and physical examination. Laxative abuse can cause hypokalemia and hyponatremia. Also, patients who abuse laxatives often develop metabolic acidosis. Long-term use can lead to osteomalacia and protein-losing enteropathy. Urinary sodium, potassium and chlorine excretion is much higher in diuretic abusers than patients with Gitelman syndrome.

Bulimia Nervosa: According to DSM IV-TR criteria:

  1. A.This disorder is defined as the presence of recurrent episodes of binge eating. There are two properties of these episodes. First one is to eat large amounts of food than most people would eat during a similar period of time. And second one is the inability to control over eating during these episodes.
  2. B.Existence of recurrent, inappropriate, compensatory behavior to avoid weight gain.
  3. C.Binge eating episodes and inappropriate compensatory behavior occur at least once per week for 3 months.
  4. D.Many individuals with bulimia nervosa have extreme concern with the body weight and shape, since they think other people judge them on the basis of their physical appearance.
  5. E.The disorder does not occur during episodes of Anorexia Nervosa

The disease usually develops after a long-term diet and failing to provide adequate weight loss. Food restriction causes binge eating episodes. In this case, abdominal distension and discomfort appears and it ends with peer pressure or self-induced vomiting. Bulimic episodes cause the feelings of guilt and depression. Thus, some of the patients use laxatives or diuretics to prevent weight gain. Most patients are at normal weight but weight fluctuations are observed. Some patients have scars on the back of their hands which proofs the efforts of induce vomiting. They generally prefer to eat alone. Health problems caused by vomiting include: gum disease, yellowing of the teeth, parotid gland enlargement, acute dilatation of the stomach, esophageal injury and, abdominal pain. There could be an increase at the levels of hypokalemia, hypomagnesemia, hyperamylasemia, metabolic alkalosis, hypercortisolism and, urinary free cortisol. Psychiatric assessment and organic pathology must be excluded for the diagnosis. Substance abuse and risk for suicide attempts should not be ignored. The goal of the treatment is to stabilize the patient's medical and nutritional status, identify and solve psychological issues, and regulate his/her eating habits.

 

Table 1. Characteristics of Syndromes in Differential Diagnosis

Gitelman syndrome

Seen in young adults. There are muscle weakness and episodes of tetany. There is no polyuria and growth retardation. Hypomagnesemia, hypokalemia and metabolic alkalosis are the most significant findings. Elevated levels of magnesium and potassium in urine and hypocalciuria are very significant findings.

Bartter syndrome

Antenatal Bartter Syndrome: Seen in the neonatal period. Polyhydramnios, prematurity, dehydration attacks due to polyuria, growth retardation, hypercalciuria and nephrocalcinosis is evident. There is sensorineural hearing loss, specific facial appearance, and most likely strabismus.

Classic Bartter Syndrome: It usually occurs in infancy. Polyuria, polydipsia, tend to dehydration and groxth retardation are seen. There is no nephrocalcinosis. Urine Na, K, and Cl excretion is increased. Normo-hypercalciuria happens. Hypokalemia is almost always accompanied by hypochloremia and metabolic alkalosis, and rarely by metabolic acidosis. Hypomagnesemia seen in 50%. Most of them have hyperreninemia and hyperaldosteronism. Their blood pressure is normal.

Diuretic abuse

Diuretic abusers have higher levels of urine sodium, potassium and chloride excretion than patients with Gitelman's syndrome. Hypomagnesemia, and metabolic alkalosis are seen.

Bulimia nervosa

The anamnesis of the patient, psychiatric examination, often exchanging weight status is suggestive for this disease. Body mass image is corrupted. Patients have scars on the backs of their hands from their repetitive efforts to induce vomiting. There can be hypotension, bradycardia, as well as gastrointestinal disorders, gum problems, and damage on the esophagus. Induced vomiting may lead to hypokalemia, hypomagnesemia, hyperamylasemia, and metabolic alkalosis. Hypercortisolism and increased urinary free cortisol levels can be seen.

Laxative abuse

Laxative abuse is usually accompanied by hypokalemia with metabolic acidosis.

 

References

1. Savaş MC. Constipation [in Turkish]. İç Hastalıkları Dergisi 2004;11(4):204-16.

2. Koşan C. Bartter’s syndrome: a case report of nephrocalcinosis [in Turkish]. AUTD 2001;33(2):57-9.

3. Doğan ÇS, Kalay S, Gökçeoğlu AU, Öztekin O, Çomak E, Koyun M, et al. Bartter syndrome type 1 [in Turkish]. Turk Neph Dial Transpl 2012;21(3):307-9.

4. Maner F. Eating disorders. World Psychiatry 2001;5(1):130-9.

5. Uçar T, Yalçınkaya F, Turner N. Renal tubular transport, diuretics and genetic defects in Bartter and Gitelman syndromes [in Turkish]. Office Journal of the Turkish Nephrology, Association 1998;7(4):173-8.

6. Bettinelli A, Bianchetti MG, Girardin E, Caringella A, Cecconi M, Appiani AC, et al. Use of calcium excretion values to distinguish two forms of primary renal tubular hypokalemic alkalosis: Bartter and Gitelman syndromes. J Pediatr 1992;120(1):38-43.

7. Lemmink HH, Knoers NV, Karolyi L, van Dijk H, Niaudet P, Antignac C, et al. Novel mutations in the thiazide sensitive NaCl cotransporter gene in patients with Gitelman syndrome with predominant localization to the C-terminal domain. Kidney Int 1998;54(3):720-30.

8. Reimann D, Gross P. Chronic, diagnosis-resistant hypokalaemia. Nephrol Dial Transplant 1999;14(12):2957-61.

9. Simon DB, Lifton RP. The molecular basis of inherited hypokalemic alkalosis: Bartter’s and Gitelman’s syndromes. Am J Physiol 1996;271(5 Pt 2):F961-6.

10. Lüthy C, Bettinelli A, Iselin S, Metta MG, Basilico E, Oetliker OH, et al. Normal prostoglandinuria E2 in Gitelman’s syndrome, the hypocalciuric variant of Bartter’s syndrome. Am J Kidney Dis 1995;25(6):824-8.

11. Bettinelli A, Tosetto C, Colussi G, Tommasini G, Edefonti A, Bianchetti MG. Electrocardiogram with prolonged QT interval in Gitelman disease. Kidney Int 2002;62(2):580-4.

12. Rose BD, Post TW. Clinical physiology of acid-base and electrolyte disorders. 5th ed. New York: McGraw-Hill, 2001:836-87.

 


Download Full Text Add to Favorite