Riuscirai a risolvere il caso anoxemia definition

Diagnosi e ragionamento

This 10 year old girl has presented with a tonic-clonic seizure in the background of fever and a headache. At first glance, this presentation is strongly suggestive of a central nervous system (CNS) infection such as meningitis or encephalitis. A vascular accident such as an intracerebral or subarachnoid hemorrhage is the other key possibility. However, her acute blindness is perplexing, as this is not typical of the above etiologies. Note that acute bilateral loss of vision is often cortical in origin – this is supported by the unremarkable fundoscopy and normal pupillary reflexes.

The presence of hypertension provides an important clue – could this be hypertensive encephalopathy ?Anoxemia definition however, it should be kept in mind that intracranial hemorrhages may also give rise to hypertension. Note that blood pressures in children should always be correlated by age and gender. In addition, complications may occur at seemingly mild degrees of hypertension (the rate of rise of blood pressure is more important than the absolute value). The drowsiness and extensor plantars are of little diagnostic value here, as these may temporarily occur in the post-ictal state. A CT scan of the brain is the fastest way to distinguish between these possibilities, and in this patient shows cerebral edema and hypodense lesions in both occipital lobes – features compatible with hypertensive encephalopathy.Anoxemia definition the occipital lesions are probably due to the posterior reversible leukoencephalopathy syndrome (PRES), and explain the loss of vision. Hypertension is almost always secondary in origin at this age – thus an underlying cause should be looked for. The facial swelling yields a hint – perhaps this is renal in origin ? Pursuing in this direction, the UFR shows red blood cell (RBC) casts and granular casts – indicating a glomerulopathy. In children of this age, the commonest glomerulopathy is acute glomerulonephritis (AGN). Another important possibility is proliferative glomerulonephritis with nephrotic syndrome. As AGN is often post-streptococcal in origin, estimation of complement levels and antibodies to streptococcal antigens might help distinguish between these etiologies.Anoxemia definition in this patient, the elevated ASOT and low C3 confirm the presence of post-streptococcal infection – and make acute poststreptococcal glomerulonephritis (APSGN) the probable diagnosis. Her management should include immediate control of the blood pressure (i.E. With IV hydralazine) and secondary prophylaxis against seizures (i.E. With diazepam). Penicillin therapy will not alter the course of the illness, but is important in preventing spread to close contacts. Note that PRES is reversible – her vision will most likely return following control of the blood pressure. There is no role for plasmapheresis in her management. Discussione

APSGN is an inflammatory disease of the kidneys which occurs following skin or throat infection with lancefield group A streptococci (GAS), or occasionally, group C or G streptococci.Anoxemia definition approximately 90% of cases occur in young children, with the median age of presentation being 6 to 8 years. The disease is rare in industrialized countries, but has an incidence of between 9.5 to 28.5 cases per 100,000 individuals per year in the developing world (where it may occur in epidemics). Note that APSGN only results from infection with nephritogenic strains of streptococci. The nephritogenic antigen present in these strains is thought to be the M protein fraction. The precise mechanism by which nephritogenic streptococci induce renal injury is not fully understood. However there is glomerular deposition of immunoglobulins and complements, indicating the involvement of an immune-mediated process which involves the complement system.Anoxemia definition the clinical manifestations of APSGN range from asymptomatic subclinical disease to rapidly progressive glomerulonephritis needing acute dialysis. Common clinical features include edema (initially facial and periorbital, with subsequent spread to peripheries), dark brown (cola colored) urine, hypertension, and reduced urine output. Some patients may recall a history suggestive of a streptococcal infection, such as pharyngitis, tonsillitis or pyoderma. After a throat infection, the latent period is usually 1 to 2 weeks, whereas in skin infections it is 3 to 6 weeks. Hypertension occurs in 60% to 80% patients, and in 5% to 10% of cases leads to hypertensive encephalopathy. In addition, the sudden elevation in blood pressure may exceed the autoregulatory capability of the posterior cerebral vasculature and cause reversible ischemia of the parietal-occipital region, i.E.Anoxemia definition posterior reversible leukoencephalopathy syndrome (PRES). Acute renal failure and acute congestive cardiac failure are the other important complications of APSGN. Urinalysis is a good first-line diagnostic investigation, as it is always abnormal, with the typical findings being hematuria, proteinuria and erythrocyte casts. The proteinuria does not enter the nephrotic range. Confirmation of the diagnosis requires evidence of streptococcal infection. Antibodies to various streptococcal antigens such as antistreptolysin O (ASO), antihyaluronidase (AH), anti-dnase B or to combinations of antigens (eg, streptozyme test) can be detected. The ASO titre is also used frequently, while positive cultures from throat and active skin lesions are an alternative.Anoxemia definition hypocomplementemia is also a feature of APSGN, with low complement C3 levels being typical. Modest elevations of urea and creatinine are common, while in severe disease hyperkalemia and acidosis may occur. Renal biopsy is not indicated unless the presentation or course of the disease is atypical. The principles of management are control of blood pressure, prevention of fluid overload, close monitoring, and treatment of complications, if any. Loop diuretics are recommended as first line agents in patients who are edematous and hypertensive. Calcium channel blockers or ACE inhibitors may be considered if hypertension persists despite diuretic therapy. Note that if malignant hypertension is present, IV nitroprusside, hydralazine or other parenteral agents should be used instead.Anoxemia definition the fluid intake should be restricted, while sodium and potassium rich foods should be avoided. Close monitoring is important to detect complications early – in all patients, the fluid balance and weight should be charted, while a close watch should be kept for alteration of the level of consciousness, diplopia or other visual abnormalities, dyspnea or bibasal crackles (indicating pulmonary congestion), tender hepatomegaly, or an elevation of blood pressure more than thrice normal. Electrolytes should also be monitored closely. This prognosis is excellent with complete recovery occurring in more than 95% of cases. Recurrence is rare. Following recovery from the acute stage, the blood pressure, urea and creatinine, complement level, and urine (for hematuria and proteinuria) should be monitored until they normalize.Anoxemia definition punti chiave

1. Hypertension in children is almost always secondary in origin.

2. Blood pressure measurements should be correlated to the age and gender of the child

3. The diagnosis of APSGN requires typical clinical findings and evidence of streptococcal infection.

4. Close monitoring is mandatory to detect and treat complications early. Bibliografia

1. Acute hypertension and hypertensive crisis in children – ped heart articles (2008)

2. Etiopathogenesis of acute poststreptococcal glomerulonephritis – saudi journal of kidney disease and transplantation (1994)

3. Acute glomerulonephritis – the japanese society of internal medicine (2006)

4. A reversible posterior leukoencephalopathy syndrome – the new england journal of medicine (1996)

anoxemia definition

5. Acute poststreptococcal glomerulonephritis in general practice: the contribution of infection to its onset and course – epidemiology and infection (1996)