METABOLIC ALKALOSIS

•   The uncomplicated  acid-base disorders, which may be of metabolic or respiratory origin, are classified as being metabolic acidosis, metabolic alkalosis, respiratory acidosis, or respiratory alkalosis.The  pH (normal 7.38 to 7.44) determines whether the primary process is an acidemia (pH < 7.38) or an alkalemia (PH > 7.44). (Note that compensation  for an alkalosis is always acidosis, while compensation  for acidosis is always alkalosis, but in either case, compensation  does not bring the pH into the normal range.)

•     Bicarbonate  levels in metabolic acidosis are <21 mM, while those in metabolic alkalosis are >28 mM. Similarly, with respiratory disorders, examine the Pac02 (normal PC02 is 35 to 40 mmHg arterial, 40 to

45 mmHg venous). in patient with respiratory alkalosis the Pac02  is <35, while with respiratory acidosis the Pac02 is >40.

•   Patients with metabolic alkalosis lose acid, and this causes an increase in the blood pH the body compensates  for – this increased pH by decreasing the respiratory rate, which increases blood CO2  levels (hypercapnia)  and increases the renal excretion of bicarbonate.  Causes of metabolic alkalosis include vomiting

(losing gastric acid), increased aldosterone secretion (which causes increased [H· ] excretion by the kidneys), and certain diuretics.

•     In contrast, metabolic acidosis increases serum acid (increased hydrogen ion concentration),  which decreases serum pH and decreases serum bicarbonate concentration.  The causes of metabolic acidosis are broken down clinically into two groups: those with a normal anion gap and those with an increased anion gap. (The serum anion gap is found by taking the serum sodium concentration  and subtracting the concentration  of two anions, namely chloride and bicarbonate.

•     Normally, the anion gap is between 10 and 16 meq/L.) Increased anion gaps result from increased unmeasured anions, such as may occur in the following clinical situations: ketoacidosis  (increased beta- hydroxybutyric  acid and acetoacetic acid, seen with diabetic ketoacidosis);  lactic acidosis (hypoxic conditions); chronic renal failure (uremia); and ingestion of certain substances such as salicylates, ethylene glycol, methanol, and formaldehyde.

•   A normal anion gap metabolic acidosis may result from either loss of bicarbonate (diarrhea) or loss of renal regeneration  of bicarbonate,  seen with renal tubular acidosis type 1 (decreased excretion of titratable acid, i.e., NH and renal tubular acidosis type 4.

•   In a patient with metabolic acidosis, the body tries to combat the decreased pH by increasing the respiratory rate (tachypnea),  which helps to raise the pH by blowing off CO2  and decreasing the serum CO2 (hypocapnia).  The body also compensates  through renal mechanisms  that increase H excretion and increase bicarbonate reabsorption.

Pulmonary edema REF: Harrison 17^th edition, chapter 48

With metabolic alkalosis, changes in central and peripheral nervous system function are similar to those of hypocalcaemia; symptoms include mental confusion, obtundation, and a predisposition to seizures, paresthesia, muscular cramping, tetany, aggravation of arrhythmias, and hypoxemia in chronic obstructive pulmonary disease. Related electrolyte abnormalities include hypokalemia and hypophosphatemia.

By inhibiting salt reabsorption in the TAL, loop diuretics increase delivery to the collecting duct.

Increased delivery leads to increased secretion of K+ and H+ by the duct, causing hypokalemic metabolic alkalosis.

This toxicity is a function of the magnitude of the diuresis and can be reversed by K+ replacement and correction of hypovolemia.

Neonates with congenital pyloric stenosis develop projectile postprandial vomiting between 2 and 4 weeks of age but may start as late as 12 weeks.

Due to this vomiting they develop hypokalemic hypochloremic metabolic alkalosis. 

Tumors responsible for ectopic secretion of ACTH are small cell carcinoma, bronchial carcinoid, medullary thyroid carcinoma, pancreatic carcinoma and pheochromocytoma. It can lead to Cushing’s syndrome.

Common clinical features of Cushing’s syndrome are central obesity with moon face, buffalo hump, thin extremities, muscle weakness, diabetes, hypertension, amenorrhea, osteoporosis, poor wound healing and psychosis.

Hypokalemia and metabolic alkalosis is seen particularly in patients with ectopic ACTH secretion. Earliest screening test for diagnosing Cushing’s syndrome is dexamethasone supression test. If its abnormal a high 24 hour urine free cortisol helps in confirming diagnosis. Late night salivary cortisol test have high sensitivity and specificity for Cushing’s syndrome.

B i.e. Uretersigmoidostomy

Ans. is ‘b^‘ i.e., I.V. Normal saline and potassium

Treatment of metabolic alkalosis due to vomiting or nasogastric suction.

o Most children with metabolic alkalosis have one of the chloride responsive etiology (e.g., vomiting).

o In these situations, administration of sufficeint sodium chloride and potassium chloride to correct volume deficit is necessary to correct metabolic alkalosis.

o Adequate replacement of gastric losses of sodium and potassium in a child with vomiting can minimize or prevent the development of metabolic alkalosis.

o With adequate intravascular volume and a normal serum potassium concentration, the kidney is able to excrete the excess bicarbonate within a couple of days.

Ans. is ‘c’ i.e., Metabolic alkalosis with paradoxical aciduria 

• Repetitive vomiting leads to hypochloremic, hypokalemic metabolic alkalosis. The urine is alkaline initially but eventually it becomes acidic (paradoxical aciduria)
• Cause of paradoxical aciduria

– Initially the kidney compensate for metabolic alkalosis by reabsorbing hydrogen and chloride ions in exchange for sodium, potassium and bicarbonate. But gradually as the body stores of sodium and especially potassium become depleted, kidney starts retaining these ions in exchange of hydrogen ions. thus the urine becomes acidic and metabolic alkaline state is further aggravated.

Answer is ‘c’ i.e. Hypokalemic metabolic alkalosis

• Repetitive vomiting leads to hypochloremic, hypokalemic metabolic alkalosis. The urine is alkaline initially but eventually it becomes acidic (paradoxical aciduria)
• Cause of paradoxical aciduria

• Initially the kidney compensate for metabolic alkalosis by reabsorbing hydrogen and chloride ions in exchange for sodium, potassium and bicarbonate. But gradually as the body stores of sodium and especially potassium become depleted, kidney starts retaining these ions in exchange of hydrogen ions, thus the urine becomes acidic and metabolic alkaline state is further aggravated.

Ans. is ‘a’ i.e., Metabolic alkalosis 

Ans. is ‘b’ i.e., Pyloric stenosis 

The answer is D (Metabolic Alkalosis)

Accelerated Hypertension is associated with metabolic alkalosis.

Accelerated Hypertension is a state in which there is renal underperfusion, high renin, and increased aldosterone. This may result in hypokalemia and metabolic alkalosis.

Ans. A (Bartter Syndrome):

Hypokalemic Metabolic Alkalosis with Hypercalciuria in a patient with normal blood pressure suggests a diagnosis of Bartter Syndrome.

Ans. is A Mineralocorticoid deficiency

Answer is C (Uretero-sigmoidostomy):

Ureterosigmoidostomy is a cause for normal anion gap type M eta bolic acidosis produced due to loss of bicarbonate in feces. All other options mentioned in the question are causes of metabolic alkalosis.

Ans. C i.e. Metabolic alkalosis with paradoxical aciduria

Ans is D  Metabolic alkalosis

These are the symptoms of addition’s Disease

Addison’s disease, also known as primary adrenal insufficiency and hypocortisolism, is a long-term endocrine disorder in which the adrenal glands do not produce enough steroid hormones.^[1] Symptoms generally come on slowly and may include abdominal pain, weakness, and weight loss. Darkening of the skin in certain areas may also occur. Under certain circumstances, an adrenal crisis may occur with low blood pressure, vomiting, lower back pain, and loss of consciousness. An adrenal crisis can be triggered by stress, such as from an injury, surgery, or infection