Quiz 2

(Ref: Harrison 19th p 312)
Management of Hyperkalemia
 Antagonism of the cardiac effects of hyperkalemia with intravenous calcium gluconate/ chloride
 Rapid reduction in plasma K+ concentration by redistribution into cells. Insulin lowers plasma K+ concentration by shifting K+ into cells.
 Beta 2 agonists, most commonly albuterol, are effective but underutilized agents for the acute management of hyperkalemia.
 Intravenous bicarbonate has no role in the routine treatment of hyperkalemia. It should be reserved for patients with hyperkalemia and concomitant metabolic acidosis, and only if judged appropriate for management of the acidosis.
 Removal of potassium by using cation exchange resins, diuretics, and/or dialysis. Sodium polystyrene sulfonate (SPS) exchanges Na+ for K+ in the gastrointestinal tract and increases the fecal excretion of K+

(Ref: Harrison 19th p 312)
 Sodium polystyrene sulfonate (SPS) exchanges Na+ for K+ in the gastrointestinal tract and increases the fecal excretion of K+.
 The recommended dose of SPS is 15-30 g, typically given in a premade suspension with 33% sorbitol to avoid constipation.
 The effect of SPS on plasma K+ concentration is slow; the full effect may take up to 24 hours and usually requires repeated doses every 4-6 hours. Intestinal necrosis is the most serious complication of SPS.

(Ref: 45, Harrison 19th p 310)
 Hyperkalemia from a variety of causes can also present with ascending paralysis; this is known as secondary hyperkalemic paralysis to differentiate it from familial hyperkalemic periodic paralysis (HYPP). The presentation may include diaphragmatic paralysis and respiratory failure.
 Cardiac rhythm disorder with hyperkalemia includes slow idioventricular rhythm.
 Hypokalemia results in slow repolarization of skeletal muscle, impairing the capacity to contract; weakness and even paralysis may ensue. The paralytic effects of hypokalemia on intestinal smooth muscle may cause intestinal ileus.

(Ref: Harrison 19th p 307)
Maximum concentration possible delivered via central = 60 mmol/L vein
Maximum concentration possible delivered via peripheral vein= 40 mmol/L

(Ref: Harrison 19th p 1401-2)
 Hepatic cirrhosis in this case is unlikely because of the absence of edema. Hence choice A is ruled out.
 Gastrointestinal fluid (Choice B) loss is unlikely because of normal blood pressure without orthostasis. Furthermore, depending on whether the fluid loss is upper (vomiting with resultant alkalosis) or lower (diarrhea with resultant acidosis), it often is accompanied by a disturbance in acid - base balance.
 Addison's disease is associated with metabolic acidosis, but in the question bicarbonate is normal with value of 24 meq.
 Uric acid can be very helpful in the differential diagnosis of hyponatremia. It is typically elevated in patients with congestive heart failure and renal failure, two other important causes of hyponatremia, and tends to be quite low in patient with SIADH. In setting of HIV infection cerebral toxoplamosis with SIADH is best answer.

(Ref: Harrison 19th p 303)
 The fluid shift in hypernatremia leads to convulsions and intracranial hemorrhage would lead to raised ICP.
 In pediatric patients with hypernatremia, extracellular and plasma volumes tend to be maintained in hypernatremia dehydration until dehydration is severe (i.e., when the patient loses > 10% of body weight). When dehydration is severe, skin turgor is reduced, and the skin develops a characteristic doughy appearance

(Ref: Harrison 19th p 314 Table 65-2)
Hyperventilation leads to Respiratory alkalosis and alkalosis is associated with low ionized calcium. Inadvertent removal of parathyroid glands during Thyroid surgery leads to Tetany.

(Ref: Harrison 19th p 323-324)
 Carbon dioxide washout in hyperventilation will lead to alkalosis. Hence to compensate for this alkalosis, some protons will be released from the proteins. This will lead to vacant space on proteins which will be occupied by calcium ions.
 Since ionic calcium will migrate to fill in the vacant space left by protons on the protein, the total ionised calcium will fall leading to tetany.