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RED-CELL SHAPE IN HYPOTHYROIDISM
1243
RED-CELL SHAPE IN HYPOTHYROIDISM Irregularly contracted red blood-cells are Sum ary small numbers in the blood-
BLOOD-FILM FINDINGS RELATED TO THYROID STATUS
present in
films of about two-thirds of patients with untreated hypothyroidism, and this has been found to be of diagnostic value. The abnormal red cells slowly disappear with treatment of the subthyroid state. INTRODUCTION
ACCOUNTS of the form of red cells in hypothyroidism describe various abnormalities. The erythrocytes are usually said to be normochromic, with little anisocytosis but with a tendency to slight macrocytosis 1; while irondeficiency anaemia and addisonian pernicious anaemia may complicate the blood-film appearances.22 Wintrobe1 states that in the true anxmia of hypothyroidism, both of spontaneous type and following surgical thyroidectomy or therapeutic radioiodine, there is no poikilocytosis save in cases of myxoedema complicated by iron deficiency or addisonian pernicious anaemia, and this accords with other published accounts.34 However, because we have been impressed by the finding of irregularly contracted red cells in peripheral-blood smears (see accompanying figure of patients) subsequently proved to have hypo-
hypothyroidism euthyroid at the time of the blood-film examination. The blood findings in the three groups are shown in the accompanying table. The blood-film was found to be positive in 1 further patient in whom hypothyroidism had not been suspected but in whom the diagnosis was subsequently established through investigations initiated by finding the characteristic misshapen cells in the blood-film. In addition, during the period of the investigation, from among approximately 15,000 blood-film examinations, the possibility of hypothyroidism was raised by the bloodfilm appearances in 5 other patients not suspected clinically of hypothyroidism and subsequently disproved-i.e., there were 5 false positives " not in the group recorded above, attributable in 2 cases to previously unsuspected chronic renal failure, and in 1 case to essential hypertension without uraemia, while in 2 cases no explanation could be found for the presence of the irregularly "
contracted red cells. DISCUSSION
thyroidism, we now believe that the detection of such misshapen cells, in appearance not unlike the burr-cells associated with microangiopathic haemolytic anaemia,6 represents a useful addition to the diagnostic signs of
hypothyroidism. We describe here
a
preliminary study designed
to
determine the frequency of this finding in patients
suspected of having hypothyroidism and validity of the finding in diagnosis
to assess
the
MATERIAL AND RESULTS
A stained blood-film was examined in 68 outpatients in whom the provisional diagnosis was stated to be hypothyroidism or myxoedema. When, some weeks later, the results of full investigations became available it was evident that the cases fell into three groups: (1) those in which the clinical suspicion of hypothyroidism had been proved or (2) disproved, and (3) treated cases of 1. Wintrobe, M. M. Clinical Hæmatology; p. 550. Philadelphia, 1967. 2. Tudhope, G. R., Wilson, G. M. Q. Jl Med. 1960, 29, 513. 3. Bomford, R. ibid. 1938, 7, 495. 4. Whitby and Britton Disorders of the Blood; p. 310. London, 1963. 5. Brain, M. C., Hourihane, D. O’B. Br. J. Hœmat. 1962, 8, 358.
The clinical diagnosis of myxcedema is generally agreed to be difficult in many cases. Both false-positive and falsenegative preliminary diagnostic conclusions are often reached; hence attempts to increase the accuracy of clinical diagnosis have been made by the construction of points-scoring systems based on the patient’s symptoms and the observable clinical signs.6 Of the 23 patients initially suspected and finally proved hypothyroid, in 15 the diagnosis was predictable at the time of their first presentation at the outpatient clinic from an examination of the initial " routine " bloodfilm, whereas in the remaining 8 no blood-film abnormality was detected. None of the 45 euthyroid patients showed the blood-film change. This constitutes a valuable control group; for in all 45 cases the haematology request form was marked " hypothyroidism " or " myxoedema ". In the 5 patients in whom the suspicion of hypothyroidism was first raised by the haematologist on the basis of the blood-film examination but was not borne out on investigation, an alternative explanation for the presence of irregularly contracted cells was readily found in 3. In no hypothyroid case with a positive blood-film was any alternative explanation for the red-cell changes detectable. The cause of this red-cell abnormality is not clear. There appears to be no correlation between any of the features of the hypothyroid state and the red-cell change. Experience of a few instances of the association observed some time ago indicates clearly that, over a period of months from the start of treatment with thyroid hormone replacement, the irregularly contracted cells disappear from the blood. This provides a valuable corollary of the validity of the association between the finding of these mis-shapen erythrocytes and subnormal thyroid function. University Department of Hæmatology, Western Infirmary, Glasgow W.1 6.
CHARLES WARDROP H. E. HUTCHISON
Billewicz, W. Z., Chapman, R. S., Crooks, J., Day, M. E., Gossage, J., Wayne, E., Young, J. A. Q. Jl Med. 1969, 38, 255.
RED-CELL SHAPE IN HYPOTHYROIDISM Irregularly contracted red blood-cells are Sum ary small numbers in the blood-
BLOOD-FILM FINDINGS RELATED TO THYROID STATUS
present in
films of about two-thirds of patients with untreated hypothyroidism, and this has been found to be of diagnostic value. The abnormal red cells slowly disappear with treatment of the subthyroid state. INTRODUCTION
ACCOUNTS of the form of red cells in hypothyroidism describe various abnormalities. The erythrocytes are usually said to be normochromic, with little anisocytosis but with a tendency to slight macrocytosis 1; while irondeficiency anaemia and addisonian pernicious anaemia may complicate the blood-film appearances.22 Wintrobe1 states that in the true anxmia of hypothyroidism, both of spontaneous type and following surgical thyroidectomy or therapeutic radioiodine, there is no poikilocytosis save in cases of myxoedema complicated by iron deficiency or addisonian pernicious anaemia, and this accords with other published accounts.34 However, because we have been impressed by the finding of irregularly contracted red cells in peripheral-blood smears (see accompanying figure of patients) subsequently proved to have hypo-
hypothyroidism euthyroid at the time of the blood-film examination. The blood findings in the three groups are shown in the accompanying table. The blood-film was found to be positive in 1 further patient in whom hypothyroidism had not been suspected but in whom the diagnosis was subsequently established through investigations initiated by finding the characteristic misshapen cells in the blood-film. In addition, during the period of the investigation, from among approximately 15,000 blood-film examinations, the possibility of hypothyroidism was raised by the bloodfilm appearances in 5 other patients not suspected clinically of hypothyroidism and subsequently disproved-i.e., there were 5 false positives " not in the group recorded above, attributable in 2 cases to previously unsuspected chronic renal failure, and in 1 case to essential hypertension without uraemia, while in 2 cases no explanation could be found for the presence of the irregularly "
contracted red cells. DISCUSSION
thyroidism, we now believe that the detection of such misshapen cells, in appearance not unlike the burr-cells associated with microangiopathic haemolytic anaemia,6 represents a useful addition to the diagnostic signs of
hypothyroidism. We describe here
a
preliminary study designed
to
determine the frequency of this finding in patients
suspected of having hypothyroidism and validity of the finding in diagnosis
to assess
the
MATERIAL AND RESULTS
A stained blood-film was examined in 68 outpatients in whom the provisional diagnosis was stated to be hypothyroidism or myxoedema. When, some weeks later, the results of full investigations became available it was evident that the cases fell into three groups: (1) those in which the clinical suspicion of hypothyroidism had been proved or (2) disproved, and (3) treated cases of 1. Wintrobe, M. M. Clinical Hæmatology; p. 550. Philadelphia, 1967. 2. Tudhope, G. R., Wilson, G. M. Q. Jl Med. 1960, 29, 513. 3. Bomford, R. ibid. 1938, 7, 495. 4. Whitby and Britton Disorders of the Blood; p. 310. London, 1963. 5. Brain, M. C., Hourihane, D. O’B. Br. J. Hœmat. 1962, 8, 358.
The clinical diagnosis of myxcedema is generally agreed to be difficult in many cases. Both false-positive and falsenegative preliminary diagnostic conclusions are often reached; hence attempts to increase the accuracy of clinical diagnosis have been made by the construction of points-scoring systems based on the patient’s symptoms and the observable clinical signs.6 Of the 23 patients initially suspected and finally proved hypothyroid, in 15 the diagnosis was predictable at the time of their first presentation at the outpatient clinic from an examination of the initial " routine " bloodfilm, whereas in the remaining 8 no blood-film abnormality was detected. None of the 45 euthyroid patients showed the blood-film change. This constitutes a valuable control group; for in all 45 cases the haematology request form was marked " hypothyroidism " or " myxoedema ". In the 5 patients in whom the suspicion of hypothyroidism was first raised by the haematologist on the basis of the blood-film examination but was not borne out on investigation, an alternative explanation for the presence of irregularly contracted cells was readily found in 3. In no hypothyroid case with a positive blood-film was any alternative explanation for the red-cell changes detectable. The cause of this red-cell abnormality is not clear. There appears to be no correlation between any of the features of the hypothyroid state and the red-cell change. Experience of a few instances of the association observed some time ago indicates clearly that, over a period of months from the start of treatment with thyroid hormone replacement, the irregularly contracted cells disappear from the blood. This provides a valuable corollary of the validity of the association between the finding of these mis-shapen erythrocytes and subnormal thyroid function. University Department of Hæmatology, Western Infirmary, Glasgow W.1 6.
CHARLES WARDROP H. E. HUTCHISON
Billewicz, W. Z., Chapman, R. S., Crooks, J., Day, M. E., Gossage, J., Wayne, E., Young, J. A. Q. Jl Med. 1969, 38, 255.