Asymptomatic period

The acquired immune deficiency syndrome (AIDS) was first recognized in 1981, and described in a cohort of young homosexual men with significant immune deficiency. Since then, human immunodeficiency virus type 1 (HIV-1) has been clearly identified as the major cause of AIDS.1 HIV-2 is much less prevalent than HIV-1, but also causes AIDS. HIV primarily targets CD4+ lymphocytes, which are critical to proper immune system function. If left untreated, patients experience a prolonged asymptomatic period followed by rapid, progressive immunodeficiency. Therefore, most complications experienced by patients with AIDS involve opportunistic infections and cancers. 

Newly diagnosed, asymptomatic patients may be observed without treatment. This asymptomatic period may last for months to a couple years. All patients with multiple myeloma will become symptomatic, and once this occurs, treatment is required. First-line treatment may be one of several therapies, including VAD, thalidomide plus steroids, and autologous transplant. Nearly all patients will progress at some point, and second-line therapy usually will include bortezomib. All patients who have bone lesions should receive monthly bis-phosphonates, with the hope of reducing pain and fractures. 

Signs and Symptoms Typically biphasic, the first phase consists of nonspecific flu-like symptoms that last about a week. This is followed by a 1-7 day asymptomatic period. The third and final phase is an abrupt onset of encephalitis, which affects the central nervous system phase producing tremors, dizziness, and altered sensorium. Recovery is prolonged. 

Most adults with disseminated histoplasmosis demonstrate a mild, chronic form of the disease. Untreated patients are often ill for 10 to 20 years, with long asymptomatic periods interrupted by relapses characterized by weight loss, weakness, and fatigue. 

Recurrent UTIs are characterized by multiple symptomatic episodes with asymptomatic periods occurring between these episodes. These infections are either due to reinfection or to relapse. 

The initial disease that follows the asymptomatic period falls into three major classes. An infected person may have symptoms for more than one of these classes. 

Antigen can be detected in serum several weeks before seroconversion and is usually undetectable during the asymptomatic period of HIV disease. Serum antigen levels decrease as the level of antibody increases and immune complexes are formed. Production of detectable HIV antigen indicates both decreased antibody production and increased expression of viral genes and is an indication of progression of disease to a serious clinical state. 

At present, we suspect that toxin-LR causes heart failure in mice, perhaps due to suddenly increased resistance to pulmonary blood flow. Heart failure in mammals is known to cause engorgement of the liver with blood. Pulmonary vascular occlusion may also cause secondary hypoxemia and shock. However, biochemical pathways that are initiated by toxin-LR and that lead to the onset of discernable signs of illness after 30 min are unidentified. The 30 min asymptomatic period following toxin injection may be associated with a toxin-initiated cascade of biochemical events which lead to overt signs of illness. 

The plasma-fluorescence emission scan with a maximum at 627 nm is the sensitive test for PV even in asymptomatic periods. 

Phosgene is a gas with low water solubility. Exposure to this gas tends to predominantly affect the lower respiratory tree. An initially asymptomatic period for the first few hours after exposure is common. Onset of symptoms may first occur 24 hours after exposure. Typical symptoms include cough and shortness of breath. Pulmonary edema may develop. 

Finally, remember that the immune system is unusually sensitive to the effects of radiation exposure. Patients who have received enough radiation to cause burns or radiation sickness may suffer from suppression of their immune systems and may require medical follow-up and antibiotic support. Because there is sometimes an asymptomatic period following the prodromal period, it may be prudent to keep patients under observation for several days after treatment. 

Because patients can be asymptomatic, periodic ophthalmoscopic examination is warranted for patients on long-term therapy with tetracycline, minocycline, or doxycycline. 

Balkan nephropathy is a chronic tuhulointerstitial disease with occult, insidious onset, usually progressing slowly with no apparent signs of symptoms. After a long asymptomatic period, the disease is manifested as chronic renal failure. Less commonly hlunt lumbar pain or renal colic may develop or, occasionally, dysuric symptoms induced by urinary tract infechon. If hematuria exists, urothelial tumor should be suspected. In an advanced case polyuria and nocturia are present due to impaired concentrating ability of the kidneys. The disease is tolerated well and the patients preserve their working ability until advanced stages of renal failure [18, 76, 88, 89]. 

Figure 12.1 Ischaemic cascade. The figure shows the sequence of events in asymptomatic period before angina starts.

Initial symptoms may be followed by latent asymptomatic period of minutes after intense exposure and up to 3 days after mild exposure, followed by return of s/s... 

However, the airway immunohistopathology in established asthma with eosinophil-dominated inflammation and remodeling is present even during relatively asymptomatic periods [78]. Studies of adults have shown that inflammation indices in the airways of asthmatics correlate with the degree of bronchial hyperresponsiveness [79]. It has been shown that bronchial hyperresponsiveness can develop as early as 4 weeks of age in those bom to atopic parents with IgE-mediated asthma, long before there are any symptoms [80]. Furthermore, bronchial hyperresponsiveness at 4 weeks of age is a clear risk factor for asthma at 6 years of age [81]. The implication of these observations is that the airway inflammation of asthma is initiated in very early life and may be present in many subjects before full-blown disease manifests [82]. 

Asymptomatic period (dissemination of the amastigote to organs spleen, liver, bone marrow, and lymphatic tissue)... 

Recurrent UTIs are characterized by multiple symptomatic infections with asymptomatic periods occurring between each episode. Either reinfection or relapse causes these infections. Reinfections are caused by a different organism than originally isolated and acconnt for the majority of recurrent UTIs. Relapse is the development of repeated infections with the same initial organism and usually indicates a persistent infectious source. 

Generally, the asymptomatic period varies with the concentration of mustard vapor (or the amount of liquid) and individual sensitivity. The latent period for eye damage is shorter than that for skin damage. Eye irritation within minutes after exposure has been reported,16,69 but the authors of these reports speculate that the irritation might have been due to other causes. 

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