Coronaviruses

Coronaviruses are named after the crown-like spikes on their surface. In the mid 1960s, the first human corona viruses were identified. The alpha coronaviruses (229E and NL63), beta coronaviruses (OC43, HKU1) and SARS-CoV are five coronaviruses that can infect human. The human coronaviruses usually cause mild to moderate upper-respiratory tract illnesses. On the other hand, SARS-CoV causes severe acute respiratory syndrome. The outbreak of Severe Acute Respiratory Syndrome (SARS) in Asia in late 2003 killed nearly 800 people.

There has been a recent outbreak of new corona virus known as nCoV-EMC, which is a beta coronavirus. This novel coronavirus is different from other coronaviruses that have been found in humans before and Also, not the same virus which caused severe acute respiratory syndrome (SARS) in 2003. However, like the SARS virus, the novel coronavirus is most similar to those found in bats. The new virus is still being learned. According to World Health Organization the new strain of the coronavirus could be passed on between people in close contact. Person infected with the novel coronavirus develops severe acute respiratory illness with symptoms of fever, cough, and shortness of breath.

Source: WHO & CDC Websites

Sperm DNA damage: Role of Antioxidants

It is now known that male fertility is compromised as a result of sperm DNA fragmentation. Many studies have suggested the implication of oxidative stress in the cause of Sperm DNA fragmentation.

Greco, et al. (2005) conducted a study to find out whether pathologically increased incidence of DNA fragmentation in ejaculated spermatozoa can be reduced by oral treatment with two antioxidants namely vitamins C and E.

The study followed sixty-four men with unexplained infertility having an elevated  percentage of DNA-fragmented spermatozoa (> or = 15%)  in the ejaculate. They were randomly separated into two groups. One group (antioxidant treatment group) received 1 g vitamin C and 1 g vitamin E daily for 2 months while the other (placebo group) received placebo.

Results revealed that the percentage of DNA-fragmented spermatozoa was markedly reduced in the antioxidant treatment group after the treatment as compared with the pretreatment values. However, no differences were found in the basic sperm parameters between the antioxidant treatment and the placebo group before or after treatment. Also, no difference in the incidence of sperm DNA fragmentation was observed in the placebo group pre and post-treatment.

These findings show that incidence of sperm DNA fragmentation can be efficiently treated by oral antioxidants in a relatively short period of about 2 month.

Reference:

Greco, E., Iacobelli, M., Rienzi, L., Ubaldi, F., Ferrero, S., Tesarik, J. 2005. Reduction of the incidence of sperm DNA fragmentation by oral antioxidant treatment. J Androl; 26 (3):349-353.

Congenital hypothyroidism ( Cretinism)

Hypothyroidism usually appears as either congenital/from birth or acquired in children.  Acquired hypothyroidism is an under activity of thyroid gland in later childhood. It occurs from a condition in which the body attacks its own tissues. When the thyroid gland gradually stops working eventually it may cause acquired hypothyroidism. This first sign of acquired hypothyroidism is growth deceleration. Children may develop constipation, cold intolerance and decreased energy. Puberty may be very slow, late or absent. There are gradual changes in facial appearance, face appears pale and puffy. Other changes include a slow heart rate, some hair loss and slow reflexes.

On the contrary, congenital hypothyroidism also aka cretinism is an under activity of the thyroid gland at birth. When the thyroid gland is poorly developed or absent it causes thyroid hormone deficiency. As a result, thyroxine the main hormone produced by thyroid gland is not produced and a condition develops called as congenital hypothyroidism. Cretinism causes growth retardation, developmental delay and other abnormal features. Congenital hypothyroidism is twice as common in females. This condition is present from birth therefore it is likely to pass in families.

Cretinism is also caused due to dietary iodine deficiency in mothers during pregnancy. In areas of severe iodine deficiency, low concentration of thyroxine in the blood (hypothyroxinemia) can cause cretinism in both mother and fetus. The iodine deficient diets affect the developing fetus, newborn and the young children. In low iodine areas cretinism is a major cause of preventable intellectual impairment in children. Thus, to prevent irreversible damage iodine should be given before conception or early in pregnancy.

The symptoms of congenital hypothyroidism appear gradually. The clinical features depend upon thyroid hormone deficiency and age of the patient. The clinical features are not characteristic at birth. During the neonatal period the earliest sign may be prolonged physiological jaundice.  The other features present are poor/difficult feeding, noisy breathing, little cry and much sleep. The abdomen is large with an umbilical hernia.

The full clinical presentation develops by 3-6 months. The appearance becomes apathetic, infantile and unconcerned with the surrounding. The milestone of development is delayed resulting in short stature. The ratio of upper segment to lower segment is large due to short legs. The forehead appears wrinkled, while the tongue is broad and protruded keeping the mouth open. The neck appears short and thick, while the hands and legs are broad and stumpy. The muscle tone is decreased, slow relaxation of ankle jerk is observed.

The laboratory investigation consists of checking serum T4 level, TSH level. Most case of congenital hypothyroidism is detected by newborn screening tests. The radiograph detects any retardation of osseous development. Thyroid scans or radio labeled iodine detect absence of thyroid tissue. The thyroid hormone replacement treatment will be for lifetime. The thyroxine used for therapy however, should not be mixed with iron or any formula containing iron or soy.

References: Davidson's principles and practice of medicine, 18th edition

Bronchiolitis in Children

Bronchiolitis is a lower respiratory tract infection in infants. It is caused by virus and results in inflammatory obstruction of the small airways of the lower respiratory tract. Bronchiolitis develops in children younger than 2 years old. The peak incidence is approximately 6 months of age. A virus, usually respiratory syncytial virus invades the bronchioles causing obstruction from mucus, cellular debris, and edema. Other viruses that   may cause bronchiolitis in infants include para influenza type 3 virus, mycoplasma and adeno virus. 

Respiratory syncytial virus (RSV) is transmitted through droplets that contain viral particles when coughing, sneezing or breathing. Adults infected with RSV can easily transmit the virus to the child. If an RSV infected person uses hands to touch a child's eye, nose, or mouth the virus spreads and infect the child. A child with bronchiolitis should be kept away from other infants and individuals susceptible to severe respiratory infection until the wheezing and fever subsides.  Infants with mothers who smoke cigarettes are at risk for contracting bronchiolitis. The symptoms include upper respiratory tract infections, runny nose (rhinorrhea), sneezing, wheezy cough and difficulty breathing.

The fever develops and gradually respiratory distress is evidenced by rapid breathing (usually 60-80breaths/min), wheezing (a whistling sound heard when the children breaths out) and cough. The rate of breathing makes it difficult to feed the children. The child seems restless and irritable because of less air. In more severe cases rapid breathing, wheezing, crackles, chest retractions and cyanosis are seen. Usually the mild cases resolve in 1-3 days while severe the course lengthens.

Virus may be detected in nasopharyngeal secretion. Treatment is based on the level of severity. In case of uncomplicated cases treatment is symptomatic. Treatment includes the use of fluids, antipyretic and humidified air or oxygen. A bronchodilator may be administered to relieve wheezing, this might be continued if a response is obtained. Antibiotics are not helpful unless there is a secondary bacterial infection. Corticosteriods are harmful for infants thus, is not indicated.