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Question 1
Incorrect
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A 45 year-old male, with behavioural changes developed euvolemic hyponatraemia. Which of the following conditions most likely predisposed the patient to develop euvolemic hyponatraemia?
Your Answer: Protracted vomiting
Correct Answer: Psychosis
Explanation:In euvolemic hyponatraemia, there is volume expansion in the body, there is no oedema, but hyponatremia occurs. Causes include: state of severe pain or nausea, psychosis, brain trauma, SIADH, hypothyroidism and glucocorticoid deficiency.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 2
Correct
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A 66 year old male, was involved in a MVA. He sustained third degree burns to his abdomen and open bleeding wound to his left leg. The patient complains of dizziness. He is a known hypertensive but during examination was found to be hypotensive. His heart rate is 120/min, with regular rhythm. What is the possible cause of his hypotension?
Your Answer: Hypovolaemia
Explanation:Hypovolemia can be recognized by tachycardia, diminished blood pressure, and the absence of perfusion as assessed by skin signs (skin turning pale) and/or capillary refill time. The patient may feel dizzy, faint, nauseated, or very thirsty. Common causes of hypovolemia are loss of blood, loss of plasma which occurs in severe burns and lesions discharging fluid, loss of body sodium and consequent intravascular water which may occur in cases of diarrhoea and vomiting. In this case the cause of patients hypotension is due to hypovolemia from both loss of plasma and blood.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 3
Correct
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What proportion of salivary secretions is contributed by the submandibular glands?
Your Answer: 70%
Explanation:The submandibular glands provide the bulk of salivary secretions contributing close to 70%. The sublingual glands provide 5% and the remainder from the parotid.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 4
Incorrect
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Which of the following conditions may cause hypervolaemic hyponatraemia?
Your Answer: Protracted vomiting
Correct Answer: Cirrhosis
Explanation:Hypovolaemic hyponatraemia: reduced extracellular fluidRenal loss of sodium and water; urine Na >20 mmol/dayCauses:Diuretic useSalt wasting nephropathyCerebral salt wastingMineralocorticoid deficiency/adrenal insufficiencyRenal tubular acidosisExtrarenal loss of sodium and water with renal conservation; urine Na <20 mmol/dayCauses:BurnsGastrointestinal lossPancreatitisBlood loss3rd space loss (bowel obstruction, peritonitis)Hypervolaemic hyponatraemia: expanded intracellular fluid and extracellular fluid but reduced effective arterial blood volumeCauses:Congestive cardiac failureCirrhosisNephrotic syndromeEuvolaemic hyponatraemia: expanded intracellular and extracellular fluid but oedema absentCauses:Thiazide diuretics (can be euvolaemic or hypovolaemic)HypothyroidismAdrenal insufficiency (can be euvolaemic or hypovolaemic)SIADH (cancer, central nervous system disorders, drugs, pulmonary disease, nausea, postoperative pain, HIV, infection, Guillain‐Barre syndrome, acute intermittent porphyria)Decreased solute ingestion (beer potomania/tea and toast diet)
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 5
Incorrect
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What is the pH of freshly formed saliva at ultimate stimulation?
Your Answer: 3.5
Correct Answer: 8
Explanation:Saliva has four major components: mucus (lubricant), α-amylase (enzyme that initiates digestion of starch), lingual lipase (enzyme that begins fat digestion), and a slightly alkaline electrolyte solution for moistening food. As the secretion rate of saliva increases, its osmolality increases. Moreover, the pH changes from slightly acidic (at rest) to basic (pH 8) at ultimate stimulation. This occurs due to increase of HCO3-. Amylase and mucus also increase in concentration after stimulation.
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This question is part of the following fields:
- Fluids & Electrolytes
- Physiology
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Question 6
Incorrect
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A 47 -year-old male was admitted due to a bleeding peptic ulcer. On his 3rd hospital day, he developed a cardiac arrhythmia. His serum potassium was markedly elevated. What is the most likely cause of hyperkalaemia in this patient?
Your Answer: Use of proton pump inhibitors
Correct Answer: Multiple blood transfusions
Explanation:Patients with gastrointestinal bleeding often require blood transfusion. Among the various side effects of blood transfusions, is the increase of potassium levels. The use of stored blood for transfusions is followed by an increase of serum potassium levels. Potassium level increases are more pronounced in patients who receive blood stored for more than 12 d. Furthermore, the lysis and destruction of red blood cells, especially in the transfusion of older PRBCs, can further increase potassium levels. Excessive use of a PPi has been associated with hyperkaelemia however would be less likely in this acute setting.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 7
Correct
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A 20-year-old woman had profuse watery diarrhoea for 2 days. She felt dizzy and weak, and thus decided to seek medical attention. At the emergency room her BP was 80/60 mmHg with a pulse of 118/min. What is the most appropriate intravenous treatment that should be given?
Your Answer: Isotonic saline
Explanation:Normal saline is typically the first fluid used when hypovolemia is severe enough to threaten the adequacy of blood circulation. It is isotonic and has long been believed to be the safest fluid to give quickly in large volumes.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 8
Incorrect
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A 25-year-old female had a painful abdomen and several episodes of vomiting. She was severely dehydrated when she was brought to the hospital. Her ABG showed a pH 7.7, p(O2) 75 mmHg, p(CO2) 46 mmHg and bicarbonate 48 mmol/l. The most likely interpretation of this ABG report would be:
Your Answer: Metabolic acidosis
Correct Answer: Metabolic alkalosis
Explanation:Metabolic alkalosis is a primary increase in bicarbonate (HCO3−) with or without compensatory increase in carbon dioxide partial pressure (Pco2); pH may be high or nearly normal. Metabolic alkalosis occurs as a consequence of a loss of H+ from the body or a gain in HCO3 -. In its pure form, it manifests as alkalemia (pH >7.40). As a compensatory mechanism, metabolic alkalosis leads to alveolar hypoventilation with a rise in arterial carbon dioxide tension p(CO2), which diminishes the change in pH that would otherwise occur. Normally, arterial p(CO2) increases by 0.5–0.7 mmHg for every 1 mmol/l increase in plasma bicarbonate concentration, a compensatory response that occurs very rapidly. If the change in p(CO2) is not within this range, then a mixed acid–base disturbance occurs. Likewise, if the increase in p(CO2) is less than the expected change, then a primary respiratory alkalosis is also present. However an elevated serum bicarbonate concentration can also occur due to a compensatory response to primary respiratory acidosis. A bicarbonate concentration greater than 35 mmol/l is almost always caused by metabolic alkalosis (as is the case in this clinical scenario). Calculation of the serum anion gap can also help to differentiate between primary metabolic alkalosis and the metabolic compensation for respiratory acidosis. The anion gap is frequently elevated to a modest degree in metabolic alkalosis because of the increase in the negative charge of albumin and the enhanced production of lactate. However, the only definitive way to diagnose metabolic alkalosis is by performing a simultaneous blood gases analysis, which reveals elevation of both pH and arterial p(CO2) and increased calculated bicarbonate.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 9
Incorrect
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A patient with chronic renal disease, missed a day of his dialysis schedule., His serum potassium was 7.6 mmol/L when his electrolytes were checked. What is the ECG finding expected in this patient?
Your Answer: U waves
Correct Answer: Tented T waves
Explanation:ECG characteristics of hyperkalaemia may show the following changes: P-waves are widened and of low amplitude due to slowing of conduction, widened QRS complex, QRS-T fusion, loss of ST segment and tall tented T waves.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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Question 10
Incorrect
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A 27-year-old female was admitted due to severe dehydration. The patient also complained of chest tightness, thus an ECG was requested. The ECG strip showed an isoelectric ST segment, upright T wave, with prominent U waves. What is the most likely electrolyte abnormality responsible for these ECG tracing?
Your Answer: Hyperkalaemia
Correct Answer: Hypokalaemia
Explanation:U waves are prominent if it is >1-2mm or 25% of the height of the T wave. Abnormally prominent U waves are characteristically seen in severe hypokalaemia.
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This question is part of the following fields:
- Fluids & Electrolytes
- Pathology
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SESSION STATS - PERFORMANCE PER SPECIALTY
