RESUMEN
CONTEXT: Thyrotoxic periodic paralysis (TPP) is a relatively common complication seen in Asian hyperthyroid patients. However, it is a rare occurrence to find a TPP case comprised of acute hypercapnic respiratory failure in patients with painless thyroiditis. PATIENT: A 29-year-old Chinese man presented with flaccid paralysis of all four limbs and he was brought to emergency room. Severe hypokalemia was found on admission. Although treatment had been initiated with potassium chloride supplementation, he went on to develop acute hypercapnic respiratory failure likely due to muscle fatigue. The patient was intubated for mechanical ventilatory support. Once his serum potassium levels were normalized, he was able to be weaned off ventilator support. Thyroid function tests showed elevated free thyroxine concentration and low thyroid-stimulating hormone concentration. He underwent a thyroid uptake scan with 131I which revealed decreased uptake rate of thyroid area. Based on the patient's clinical presentation and associated findings, we diagnosed him with TPP due to painless thyroiditis. We have reviewed TPP cases caused by painless thyroiditis and TPP cases associated with acute hypercapnic respiratory failure. CONCLUSION: It is important to note that potentially fatal complications such as acute hypercapnic respiratory failure might occur in acute attacks of TPP even in cases of TPP due to painless thyroiditis.
Asunto(s)
Hipercapnia/complicaciones , Parálisis Periódica Hipopotasémica/complicaciones , Insuficiencia Respiratoria/complicaciones , Tiroiditis/complicaciones , Adulto , Pueblo Asiatico , Humanos , Hipercapnia/diagnóstico , Hipercapnia/etnología , Hipopotasemia/etnología , Hipopotasemia/etiología , Parálisis Periódica Hipopotasémica/diagnóstico , Parálisis Periódica Hipopotasémica/etnología , Masculino , Paraplejía/etnología , Paraplejía/etiología , Insuficiencia Respiratoria/diagnóstico , Insuficiencia Respiratoria/etnología , Tiroiditis/diagnóstico , Tiroiditis/etnologíaRESUMEN
INTRODUCTION: A previous study has suggested that the Human Leukocyte Antigen (HLA) allele DQB1*06:02 affects hypoxic ventilatory response (HVR) but not hypercapnic ventilatory response (HCVR) in an Asian population. The current study evaluated the relationship in Caucasians and Asians. In addition we assessed whether gender or polymorphisms in genes participating in the control of breathing affect HVR and HCVR. METHODS: A re-breathing system was used to measure HVR and HCVR in 551 young adults (56.8% Caucasians, 30% Asians). HLA-DQB1*06:02 and tagged polymorphisms and coding variants in genes participating in breathing (PHOX2B, GPR4 and TASK2/KCNK5) were analyzed. The associations between HVR/HCVR and HLA-DQB1*06:02, genetic polymorphisms, and gender were evaluated using ANOVA or frequentist association testing with SNPTEST. RESULTS: HVR and gender are strongly correlated. HCVR and gender are not. Mean HVR in women was 0.276±0.168 (liter/minute/%SpO2) compared to 0.429±0.266 (liter/minute/%SpO2) in men, p<0.001 (55.4% higher HVR in men). Women had lower baseline minute ventilation (8.08±2.36 l/m vs. 10.00±3.43l/m, p<0.001), higher SpO2 (98.0±1.3% vs. 96.6±1.7%, p<0.001), and lower EtCO2 (4.65±0.68% vs. 4.82±1.02%, p = 0.025). One hundred and two (18.5%) of the participants had HLA-DQB1*06:02. No association was seen between HLA-DQB1*06:02 and HVR or HCVR. Genetic analysis revealed point wise, uncorrected significant associations between two TASK2/KCNK5 variants (rs2815118 and rs150380866) and HCVR. CONCLUSIONS: This is the largest study to date reporting the relationship between gender and HVR/ HCVR and the first study assessing the association between genetic polymorphisms in humans and HVR/HCVR. The data suggest that gender has a large effect on hypoxic breathing response.
Asunto(s)
Cadenas beta de HLA-DQ/genética , Hipercapnia/genética , Hipoxia/genética , Canales de Potasio de Dominio Poro en Tándem/genética , Respiración , Adolescente , Adulto , Análisis de Varianza , Pueblo Asiatico , Femenino , Genotipo , Voluntarios Sanos , Proteínas de Homeodominio/genética , Humanos , Hipercapnia/etnología , Hipoxia/etnología , Masculino , Polimorfismo Genético , Receptores Acoplados a Proteínas G/genética , Factores Sexuales , Factores de Transcripción/genética , Ventiladores Mecánicos , Población Blanca , Adulto JovenRESUMEN
A video slideshow of the Viewpoint by Michael J. White is available here.
Asunto(s)
Negro o Afroamericano , Circulación Cerebrovascular , Hipercapnia/etnología , Hipercapnia/fisiopatología , Arteria Cerebral Media/fisiopatología , Vasodilatación , Femenino , Humanos , MasculinoRESUMEN
NEW FINDINGS: What is the central question of this study? The main purpose of this investigation is to determine whether there is a difference in cerebral vasodilatory capacity in response to rebreathing-induced hypercapnia between African Americans and Caucasian Americans. What is the main finding and its importance? College-aged African Americans have reduced cerebral vasodilatory capacity during hypercapnia when compared with Caucasian counterparts, a finding that suggests cerebral vascular dysfunction in this population. These findings may contribute to the understanding of the greater prevalence of cerebral vascular disease in this population. African Americans (AAs) have increased risk for cardiovascular, cerebral vascular and metabolic disease, including hypertension, stroke, coronary artery disease, metabolic syndrome and type II diabetes, relative to Caucasian Americans (CAs). While it is accepted that endothelial function is impaired in AAs, less is known regarding their cerebral vasodilatory capacity in response to hypercapnia. We hypothesized that AAs have a reduction in the total range of change in cerebral blood flow velocity (CBFV) measured in the middle cerebral artery and an index of cerebral vascular conductance (CVCI) in response to changes in the partial pressure of end-tidal carbon dioxide (P(ET,CO2)) during rebreathing-induced hypercapnia when compared with CAs. Twenty-one healthy, college-aged AA (10 male) and 21 age- and sex-matched CA (10 male) subjects participated in this study. A four-parameter logistic regression was used for curve fitting the responses of CBFV and CVCI relative to changes in P(ET,CO2). The total ranges of change in CBFV (101 ± 18 versus 69 ± 23%; P < 0.001) and CVCI (83 ± 21 versus 58 ± 21%; P < 0.001) as well as the maximal increase in CBFV (205 ± 24 versus 169 ± 24%; P < 0.001) and CVCI (188 ± 30 versus 154 ± 19%; P < 0.001) were reduced during hypercapnia in AAs relative to CAs despite a similar increase in P(ET,CO2) (change, 15 ± 3 versus 15 ± 3 mmHg; P = 0.65). In conclusion, these data indicate that AAs have attenuated cerebral vascular capacity to respond to hypercapnia when compared with CAs.
Asunto(s)
Negro o Afroamericano , Circulación Cerebrovascular , Hipercapnia/etnología , Hipercapnia/fisiopatología , Arteria Cerebral Media/fisiopatología , Vasodilatación , Adulto , Factores de Edad , Velocidad del Flujo Sanguíneo , Dióxido de Carbono/sangre , Estudios de Casos y Controles , Femenino , Homeostasis , Humanos , Hipercapnia/sangre , Modelos Logísticos , Masculino , Arteria Cerebral Media/metabolismo , Flujo Sanguíneo Regional , Factores de Tiempo , Adulto JovenRESUMEN
En las grandes alturas se han estudiado los efectos del sueño y su influencia en la etiopatogenia del soroche crónico o Enfermedad de Monge. Se hizo cateterismo cardíaco derecho durante la noche y se midió la ventilación pulmomar en voluntarios adultos normales (adaptados y en pacientes con enfermedad de Monge (desadaptados). En niños sólo se midió la ventilación pulmonar. A 4540 y a 4330 msnm. durante el sueño se producen los siguientes efectos agudos: hipoventilación, hipoxemia moderada y severa, hipercapnia, hipertensión pulmonar moderada y severa, disminuyendo el consumo de oxígeno, el débito cardíaco y el volumen de expulsión ventricular, leve incremento de la frecuencia cardíaca, acidemia y, en los desadaptados, además, se observa hipertensión diastólica sistémica. Los cambios son más acentuados en los desadaptados. En los niños el sueño ocasiona una disminución de la ventilación pulmonar siendo ésta de mayor magnitud que en los adultos. Al despertar, los residentes altoandinos están normales y sin signos, síntomas, ni ninguna condición neurológica patológica. Durante el sueño los adaptados adquieren las características que tienen los desadaptados en vigilia. Hipoventilación, hipoxemia y policitemia acentuadas, hipercapnia, hipertensión pulmonar moderada y severa son las principales características de la Enfermedad de Monge, siendo la hipoventilación el principal factor causal de ellos. Por la hipoxemia aguda durante el sueño los residentes altoandinos, teóricamente ascienden a una altura mayor que aquella en la cual están durmiendo. Desde los recién nacidos hasta la senectud la hipoventilación e hipoxemia se acentúan por el sueño, por el envejecimiento, por la mayor altitud de residencia, y más aún en las grandes alturas, la hipoxemia también se acentúa por el peculiar comportamiento fisiológico de la curva de disociación de la oxihemoglobina y, probablememte, por los mecanismos mediante los cuales la policitemia ocasiona anoxemia y viceversa y por la precoz desensibilización hipóxica de los quimiorreceptores periféricos. De esta manera, ya sea en forma aislada o asociada, el sueño y las otras variables contribuyen en la etiopatogenia de la enfermedad de Monge, condicionando que algunos adaptados vayan adquiriendo lenta y progresivamente las características que tienen los pacientes con Enfermedad de Monge. Así, la Enfermedad de Monge sería la resultante de un proceso bio-ecológico y no la de un proceso patológico