Certain situations are more likely to precipitate arrhythmias such as exercise or mental stress in the LQT1 subtype, sudden loud noise in the LQT2 subtype, and during sleep or immediately upon waking in the LQT3 subtype.Romano–Ward syndrome can be differentiated from other forms of long QT syndrome by Romano-Wards sole involvement of the heart. While other forms of long QT syndrome are associated with deafness (Jervell and Lange-Nielsen syndrome), intermittent weakness and bone abormailities (LQT7, Andersen–Tawil syndrome), and autism spectrum disorder (LQT8, Timothy syndrome), these extra-cardiac manifestations are not seen in Romano-Ward. Causes
Romano–Ward syndrome is a descriptive term for a group of subtypes of long QT syndrome, specifically subtypes LQT1-6 and LQT9-16. Several subtypes of Romano–Ward syndrome have been described based on the underlying genetic variant. These subtypes differ in clinical presentation and their response to treatment. There is robust evidence that the genetic variants associated with the three most common subtypes (LQT1, LQT2 and LQT3) are truly causative of the syndrome. However, there is uncertainty as to whether some of the other rarer subtypes are truly disease-causing by themselves or instead make individuals more susceptible to QT prolongation in response to other factors such as medication or low blood potassium levels (hypokalaemia). LQT1
LQT1 is the most common subtype of Romano–Ward syndrome, responsible for 30 to 35% of all cases. The gene responsible, KCNQ1, has been isolated to chromosome 11p15.5 and encodes the alpha subunit of the KvLQT1 potassium channel.
Additionally, hypercalcemia can decrease the reabsorption of water in the kidneys collecting ducts by suppressing antidiuretic hormone (ADH) receptors, contributing to more hypovolemia. Hypercalcemia also results in lower parathyroid hormone (PTH) levels via a negative feedback loop, in which calcium-sensing receptors in the PTH gland are activated by the elevated calcium levels to inhibit PTH production, thus decreasing renal reabsorption of calcium.Hypovolemia then leads to metabolic alkalosis (increase in blood pH) by stimulating bicarbonate reabsorption in order to maintain extracellular volume. In summary, the symptoms of alkalosis is the net result of over-consumption of absorbable alkali, hypercalcemia-induced hypovolemia, and impaired glomerular filtration rate. Alkalosis, in turn, increases calcium-reabsorption from the distal tubules of the nephron, thus exacerbating the hypercalcemia and hypovolemia.Altogether, these result in a cycle of hypercalcemia, alkalosis, and renal injury characteristic of MAS. Diagnosis
Prior to an official diagnosis of milk-alkali syndrome, other causes of hypercalcemia must be ruled out. Other causes of hypercalcemia can include elevated vitamin D levels, hyperthyroidism, and hyperparathyroidism. Physical Examination:Symptoms such as vertigo, confusion, apathy, nausea and vomiting, anorexia, tremors, psychosis, myalgia, polyuria, abnormal calcifications such as renal calcifications, and pruitus could be observed in people. Lab work:
Lab work must be done to diagnose milk-alkali syndrome. Lab workup includes serum calcium levels, parathyroid hormone (PTH), phosphorus, creatinine, blood urea nitrogen (BUN), magnesium, and vitamin D levels. Primary hyperparathyroidism has to be excluded. Diagnosis is made by looking at past medical history and laboratory studies. Serum calcium levels: high serum calcium levels. PTH: low serum PTH levels are indicative of MAS.