Which one of the following causes low-volume erythrocytosis?
The question asks to identify which condition causes low-volume erythrocytosis. Erythrocytosis refers to an increase in the number of red blood cells or the hematocrit. Low-volume erythrocytosis specifically means the increase in hematocrit is due to a decrease in plasma volume, making the red blood cells more concentrated, rather than an absolute increase in the total red blood cell mass.
Understanding Erythrocytosis Types
Erythrocytosis can be classified based on the cause:
- Absolute Erythrocytosis: An increase in the total red blood cell mass. This can be primary (like Polycythemia Vera) or secondary (like response to hypoxia).
- Relative (or Apparent/Low-Volume) Erythrocytosis: An increase in the hematocrit or red blood cell count that is not due to an increase in red blood cell mass, but rather due to a decrease in plasma volume.
Analyzing Causes of Low-Volume Erythrocytosis
Let's examine each option:
Polycythemia Vera is a myeloproliferative disorder where the bone marrow produces too many red blood cells, along with white blood cells and platelets. This results in an absolute erythrocytosis with an increased red cell mass, not a low-volume or relative erythrocytosis.
Testosterone stimulates the bone marrow to produce more red blood cells. Therefore, testosterone therapy typically leads to an absolute erythrocytosis, increasing the total red blood cell mass, rather than a low-volume type.
Gaisbock's syndrome, also known as stress erythrocytosis or spurious erythrocytosis, is characterized by an elevated hematocrit level that results from a decrease in plasma volume. This is often observed in stressed individuals, particularly middle-aged men, who may also have hypertension. This condition fits the definition of low-volume (relative) erythrocytosis.
Exposure to high altitudes leads to lower oxygen levels (hypoxia). The body responds by producing more erythropoietin, a hormone that stimulates the bone marrow to produce more red blood cells. This results in an absolute erythrocytosis to improve the blood's oxygen-carrying capacity.
Conclusion on Low-Volume Erythrocytosis
Based on the analysis, Gaisbock's syndrome is the condition among the options provided that causes low-volume erythrocytosis due to a reduction in plasma volume.
Important Questions from Miscellaneous
A 35 year old male presents with increased urine output. On evaluation, his urinary output was around 4L/day; urinary osmolality was 200 mosmol/L. Which of the following are various differential diagnosis ?
I. Psychogenic polydipsia
II. Solute diuresis
III. Central diabetes insipidus
IV. Nephrogenic diabetes insipidus
Select the correct answer using the
code given below:Under which one of the following conditions, the HPA axis suppression is likely to result in crisis due to adrenal insufficiency following withdrawal of glucocorticoids?
A 36 year old man presents with decreased apetite, mouth soreness, diarrhoea and irritability. On examination he has a bright red tongue with a pigmented scaly rash around the neck. Which one of the following food items in his diet has a bearing on his disease?
Koebner phenomenon is seen in which one of the following conditions?
Consider the following regarding the human hair growth cycle:
I. Anagen is a phase of active hair growth
II. Telogen is a transitional phase
III. Catagen is a resting phase
Which of the statements given above is/are correct?
