SENSIBILITY TO THE ENVIRONMENTAL TEMPERATURE IN DOWN SYNDROME PERSONS. AN EPIDEMIOLOGICAL INVESTIGATION ON 432 CASES

Renato COCCHI, a neurologist and a medical psychologist


(Italian translation)  

  Summary.

 During the first visits of a consecutive series not selected of 432 Italian subjects with syndrome of Down (254 M and 178 F, chromosomal diagnosis  normally spread; average age at the first consultation: 70 months; All living in family) it was investigating their sensibility to the environmental temperature, by asking the parents.  

It resulted how  the 67.36% of them suffered the heat; the 5.78%  were more sensitive to the cold; the 2.08% sensitive to both and the 19.61% as indifferent to both.  In  4.1 % the datum was not collected. No gender difference appeared.  Such  data were interpreted as for the individual variability of the syndrome of Down.

There is a clear tendency, at least in Italy, to intolerance to the heat, a possible sign of ill functioning of the hypothalamic centre controlling the body temperature.  

Key words: Stress, Down’s syndrome, temperature sensitivity, epidemiology, 432 cases.


Down's syndrome

Mental retardation

Symptoms

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During the first visits of Down's syndrome subjects, I had the habit of asking was  the present individual usually suffers the heat, the cold or he is indifferent to the environmental temperature.  Sometimes this question embarrasses the parents because it can contrast with a present susceptibility to the respiratory infections, traditionally attributed the cold.  

To be sure of  an exact answer, in these cases, I ask if the child stretches to throw off one's bed  cover at night; Or if he uses to stay in the shade or in the water when at the sea resort; Or if  he easily sweats independently from any physical effort, or if in summer he inclined to lie down to the floor of his home.  In this way I gained the direction of this symptom in the nearly all subjects I examined since 1979.

To appraise in an exact way the course of this symptom I did an epidemiological investigation on 432 consecutive cases.

  Materials and method. I reexamined all the clinical records of a consecutive, not selected, series of 432 Down subjects. They were all raised in their families, all visited personally by myself from 1979 to May 1989, and coming from all the Italian regions. I collected the following data:
- sex;
- chromosomal diagnosis;
- age to the first visit;
- sensibility to the environmental temperature: if the subject suffered more the heat or the cool or both or he was indifferent  to both.
 I did the statistic analysis of the results with the Chi Square  test.  


Results

 The reexamination of the 432 records counted the following  data.   

 

Table 1: Epidemiological data.

 

No. Of Ss

432

100.00 %

M

254

58.26 %

F

178

41.74 %

M/F ratio

 

142.70 %

 

Age at first consultation in months: average

70.11 +/- 65.0

 

Chromosomal diagnoses:

 

 

Standard trisomy 21

397

91.90 %

Mosaicisms

15

4.37 %

Unknown  (only clinical diagnosis)

5

1.16 %

 

 

 

 

 

Table 2: Sensitivity to environmental temperature.  

Type of sensitivity

Males

%

Females

%

Suffering from heat

177

40.97

114

26.39

Suffering from cool

9

2.08

16

3.70

Suffering from heat and cool

6

1.39

3

0.69

Indifferent to heat and cool

51

11.81

38

8.80

Data not collected

11

2.55

7

1.62

Chi Square = 6.209, with 4 df, p = 0.184 NS.  

Discussion.

 I need to say at once that the distribution of the chromosomal anomalies, that is not far from known both in Italy and abroad,  the M/F ratio and the origin from all the country make  this  series of Down a representative sample, at least of the Italian population of the affected.   

Already 10 years ago (Cocchi 1979), as for a syndrome from possible GABA deficiency, I turned me to investigate the sensitivity to the cold of the subjects with that clinical frame.  Of course, starting then to occupy me of the Downs, I picked up even this symptom during the first examination. I quickly realized that  most of them were going in the opposite. So, I usually found, in much of them, a scarce tolerance for the heat.

This reduced tolerance of the subject Down to the environmental temperature is a datum interested many researchers. Brinkworth (1989) wrote: "I am always treating Down children for their poor control of the thermoregulation, as susceptible to have difficulties both for the high  and low temperature. As Davidenkova, in the 1966, reported,  defects of the nucleus rubeus lead to a deficit of the thermoregulation in Down children. Since they miss even the frontal sinuses, their brains have more facility to lose heat  in the surrounding air with the cool.  

The fact that they not have a normal vasoconstriction in reply to the cool means that they risk  modest hypothermia. Therefore they have the need to be well covered with the cold, but not just the temperature crosses 39 degrees they stretch even to get overheated. 

So because much among them have reduced sweat glands, in comparison with the normal people.  Usually they sweat with easiness only to the head and to the nape,  a fact  better known  in infants. In the countries of big heat, as the Sudan, where the temperature can go over  59 degrees, the mama of one of my patients,  the sister of a pediatrician,  reports that nobody survives till the adult life in this conditions. This happens by the fact that the oxygen consumption of these subjects raises enormously to every degree of increasing temperature and the heart frequency accelerates till the death, mainly in those 40% with  heart defects."  

The words of Brinkworth, of notable interest, point out problems that arise even from the present investigation. First of all, the reaction to the heat or to the cold not the same in all the Down Italian 
children, because they show still a time the great symptoms' variability of the syndrome. As for it I did not find any significant difference related to gender. In the second place, it has to think that the average temperature of the country from which  data come,  is an important element. We have the cool for the north of the URSS, warm for the Sudan and an intermediate situation for Italy.  

Even admitting that it corresponds to a significant variable, we should however suppose that the intolerance to the heat is more reduced, and more dangerous in comparison with the intolerance the cold. The presence of a poor tolerance to the heat in  the 2/3 of the cases of this series, coming from a country of a temperate climate, seems an element in favour of a hypothesis of this type.   

Much more that the  frontal sinuses lack  and a debit vasoconstriction or reduced sweat glands, if they are unfavourable in a climatic situation  should  be protective features in that opposite.

 I think however that the control of the sensibility and of the tolerance to the environmental temperature  is not only a problem of peripheral structures, but rather referable to a bad running  of brain structures.    More that the nucleus ruber, asserted  by Davidenkova (1966), it seems to me that it is the hypothalamus, where it exists a special centre of the thermoregulation, the structure that  has increased probability to be set in cause.

 Since its richness in GABA receptors (Fagg and Foster, 1983), to which I  attributed the responsibility of the symptom "poor cold tolerance" in a paper where I explained  a syndrome of reduced GABA synthesis and reduced type A GABAergic inhibition  (Cocchi, 1988).  Already I reported in that paper the different course of the symptom in  Downs, even if did not quantify it yet.


As for an excess sensibility to the cool, I wrote that a GABAergic therapy can favourably act on the poor tolerance to cold, by modifying, with greater evidence,  the symptom "cool hands and  feet."  In Downs intolerant for the heat, the symptom seems recall different neurochimical unbalance, once a time involving the GABA.

he situation of continuous endogenous metabolic stress, creditable to the acceleration of all the metabolisms, whose control genes are on the chromosome 21, tripled in these subjects, has lead to suggest a reduced type A GABAergic inhibition not due to a lack of this neurotransmitter, but to stop functioning by stress of the respective receptors, and an increase of the type B GABAergic inhibition.   

As a support to this hypothesis there is the fact that the baclofen, 
a type B GABAergic agonist, in the rat can act by directly stimulating the hypothalamic thermoregulatory centre. The result of which, is an increase till two degrees of the body temperature (Horton, LeFeuvre, Rothwel and Stock, 1988).

 On other hand, an inhibitor of the GABA-transaminase as the ethanolamine-O-sulfate, which increases the brain GABA [and then increases even the type B GABAergic inhibition]  has the same effect (Sykes, Prestwich and Horton, 1984 ). It needs even to say that a poor tolerance for the heat  is not an exclusive symptom of most  Down subjects. It can be found even in many persons called "neurotics" and that however they have a scarce ability to modulate stress reaction, with a tendency to the parasympathetic outflow.  

 

Conclusion.

 The investigation carried out  on a consecutive not selected series  of 432 Italian Down subjects making up a representative sample of the respective population, has shown that the sensibility to the environmental temperature is a varying symptom, with  2/3  of them with poor tolerance to the heat and 1/5 as  indifferent to both the heat and the cool.  

The poor tolerance the cold, even present, not overcomes 6% of the investigated individuals, and about 3% stand badly the heat that the cool. In its variability, this symptom is a further sign of the ample individual differences that always coexist in Down syndrome persons, even if they show the same chromosomal anomaly (mostly, the standard trisomy 21).

It is possible that the type of sensibility to heat and cool of this Italian sample of Down subjects has a relationship  even to the Italian climate. However, it seems more probable that there exists  differential sensibility, more accentuated for the heat.

 

References.


 Brinkworth R., 1989  (comunicazione personale).

 Cocchi R.: Drug therapy in endogenous depression with possible primary GABA deficiency clinically detected: 38 new cases. Riv. Sper. Freniat. 1979, 103: 645-653.      

Cocchi R.:  Hypo-A-GABA-erge  Depression  bei Kindern. Klinisches  Bild und mit neurochemischen Mechanismen verbundene Symptome. In Friese H.-J., Trott G.-E. (eds): Depression in Kindheit und Jugend. Huber, Bern 1988: 126-133.  Davidenkova E.F.: Bolezn` Dauna (Sindrome di Down). Capitolo: Profilaktika e lechenie (Prevenzione e trattamento). Moskow Publ. House 1966: 185-195 (in russo; citato da Brinkworth).  Fagg G.E., Foster A.C.: Amino acid neurotransmitters and their pathway in the mammalian central nervous system. Neuroscience 1983, 9: 701-719.  Horton R.W., Le Feuvre R.A., Rothwell N.J., Stock M.G.: Opposing effects of activation of central GABA A and GABA B receptors on brown fat thermogenesis in the rat. Neuropharmacology 1988, 27: 363-366.  Sykes C., Prestwich C., Horton R.: Chronic administration of the GABA transaminase inhibitor ethanolamine-O-sulphate leads to up-regulations of GABA binding sites. Biochem. Pharmac. 1984 33: 387-393.

            On Internet since November 2002: Copyright by Renato Cocchi, 2002.   

Author’s address: dr Renato COCCHI, via Rabbeno, 3
42100 Reggio Emilia (Italy)  

renatococchi@libero.it

 

 

Testo in italiano

Down's syndrome

Mental retardation

Symptoms

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