The right ventricle pumps blood to the lungs to get oxygen, while the left ventricle pumps blood to the rest of the body to provide oxygen to tissues. A ventricular septal defect results in the mixing of oxygen-rich blood with oxygen-poor blood, increasing strain on the heart and lungs. Pathophysiology
During ventricular contraction, or systole, some of the blood from the left ventricle leaks into the right ventricle, passes through the lungs and reenters the left ventricle via the pulmonary veins and left atrium. This has two net effects. First, the circuitous refluxing of blood causes volume overload on the left ventricle. Second, because the left ventricle normally has a much higher systolic pressure (~120 mmHg) than the right ventricle (~20 mmHg), the leakage of blood into the right ventricle therefore elevates right ventricular pressure and volume, causing pulmonary hypertension with its associated symptoms. In serious cases, the pulmonary arterial pressure can reach levels that equal the systemic pressure. This reverses the left to right shunt, so that blood then flows from the right ventricle into the left ventricle, resulting in cyanosis, as blood is by-passing the lungs for oxygenation.This effect is more noticeable in patients with larger defects, who may present with breathlessness, poor feeding and failure to thrive in infancy. Patients with smaller defects may be asymptomatic. Four different septal defects exist, with perimembranous most common, outlet, atrioventricular, and muscular less commonly. Diagnosis
A VSD can be detected by cardiac auscultation. Classically, a VSD causes a pathognomonic holo- or pansystolic murmur.
The confirming diagnosis remains culturing the fungus from the skin, sputum, synovial fluid, and cerebrospinal fluid. Smears should be taken from the draining tracts and ulcers. Cats with sporotrichosis are unique in that the exudate from their lesions may contain numerous organisms. This makes cytological evaluation of exudate a valuable diagnostic tool in this species. Exudate is pyogranulomatous and phagocytic cells may be packed with yeast forms. These are variable in size, but many are cigar-shaped. Differential diagnosis
Differential diagnosis includes: leishmaniasis, nocardiosis, mycobacterium marinum, cat-scratch disease, leprosy, syphilis, sarcoidosis and tuberculosis. Prevention
The majority of sporotrichosis cases occur when the fungus is introduced through a cut or puncture in the skin while handling vegetation containing the fungal spores. Prevention of this disease includes wearing long sleeves and gloves while working with soil, hay bales, rose bushes, pine seedlings, and sphagnum moss. The risk of sporotrichosis in cats is increased in male cats that roam outdoors. Accordingly, the risk may be reduced by keeping cats indoors or neutering them. Isolating infected animals can also be a preventive measure. The risk of spread from infected cats to humans can be reduced by appropriate biosafety measures, including wearing protective equipment when handling a cat with suspected sporotrichosis and by washing hands, arms and clothing after handling the cat. Treatment
Treatment of sporotrichosis depends on the severity and location of the disease. The following are treatment options for this condition:
Oral potassium iodidePotassium iodide is an anti-fungal drug that is widely used as a treatment for cutaneous sporotrichosis.