There is a suspicion that chronic hemolysis causing chronically depleted nitric oxide may lead to the development of pulmonary hypertension (increased pressure in the blood vessels supplying the lung), which in turn puts strain on the heart and causes heart failure.Historically, the role of sleep and night in this disease (the "nocturnal" component of the name) has been attributed to acidification of the blood at night due to relative hypoventilation and accumulation of carbon dioxide in the blood during sleep. This hypothesis has been questioned by researchers who note that not all those with PNH have increased hemolysis during sleep, so it is uncertain how important a role sleep actually plays in this disease. Diagnosis
Blood tests in PNH show changes consistent with intravascular hemolytic anemia: low hemoglobin, raised lactate dehydrogenase, raised bilirubin (a breakdown product of hemoglobin), and decreased levels of haptoglobin; there can be raised reticulocytes (immature red cells released by the bone marrow to replace the destroyed cells) if there is no iron deficiency present. The direct antiglobulin test (DAT, or direct Coombs test) is negative, as the hemolysis of PNH is not caused by antibodies. If the PNH occurs in the setting of known (or suspected) aplastic anemia, abnormal white blood cell counts and decreased platelet counts may be seen at this.
Geographical location, present season, and variables associated with cats (such as exposure and degree of flea infestation) all play a factor in the prevalence of CSD within a population. In warmer climates, the CSD is more prevalent during the fall and winter, which may be attributed to the breeding season for adult cats, which allows for the birth of kittens. B henselae, the bacterium responsible for causing CSD, is more prevalent in younger cats (less than one year old) than it is in adult cats.To determine recent incidence of CSD in the United States, the Truven Health MarketScan Commercial Claims and Encounters database was analyzed in a case control study from 2005 to 2013. The database consisted of healthcare insurance claims for employees, their spouses, and their dependents. All participants were under 65 years of age, from all 50 states. The length of the study period was 9 years and was based on 280,522,578 person-years; factors such as year, length of insurance coverage, region, age, and sex were used to calculate the person-years incidence rate to eliminate confounding variables among the entire study population.A total of 13,273 subjects were diagnosed with CSD, and both in- and outpatient cases were analyzed. The study revealed an incidence rate of 4.5/100,000 outpatient cases of cat-scratch disease. For inpatient cases, the incidence rate was much lower at 0.19/100,000 population. Incidence of CSD was highest in 2005 among outpatient cases and then slowly declined. The Southern states had the most significant decrease of incidence over time.