In certain epidemics nephritis is especially frequent. It is noted usually after the vesicles are dried up and it is important to note that a very severe nephritis may follow a light attack of varicella.
Precautions against nephritis, such as long rest in bed and a milk diet, owing to the rarity of the complication are rarely employed. Chil dren who have previously had nephritis should have all such precautions taken. In all cases where there is nephritis the treatment should be undertaken in earliest as a severe nephritis may otherwise result.
Arthritis varicellosa may occur during the eruptive period or later. It is usually polyarticular but only one joint may be affected. It may start acutely or it may come on gradually. There are two forms, a simple serous form and a severe suppurative form. This last may follow secondary infections by pus germs, or occur through general blood in fection or through the lymphatics from some neighboring site of infec tion. The prognosis in every case must be guarded owing to the danger of general infection.
Complications involving the nervous system are much less frequent after varicella than after the other infectious diseases. W. Gay (1894) observed a case of paraplegia with loss of power, sensibility and reflexes of the legs. This occurred in a boy, two and one-half years old, fourteen days after a normal varicella. Recovery took place in three weeks. Under similar circumstances Marian noted a case of monoplegia which affected the arm and also a case of external oplithalmoplegia of muscular origin. Chorea, multiple sclerosis and encephalitis have also been reported.
Secondary infections with pus-forming bacteria are important. It is not infrequent for most of the vesicles to be infected and become pustules. This may occur in well-cared-for children but more often happens in the weak and poor. Scratching and uncleanliness are the most common causes but crust. pustules are the rule in the regions soiled by the urine and stools in uncleanly children. Irritating applications may also cause pustules. The pustules run a longer course than the vesicles, reaching maturity in from 6 to 10 days. They are surrounded by a red inflamed area and in the middle there is a reddish brown umbili cation so that it resembles a variola pustule. These are designated by
the French as "la pustule en cocarde." Three weeks or even a month may elapse before the crust falls off. The general symptoms may be severe and these cases may be mistaken for smallpox. Local mations as phlegmons, furuncles, subcutaneous abscesses and erysipelas may occur in the course of the disease. General infection may result, with other local manifestations, in thrombosis of the vessels and also severe general symptoms. Amongst other things the following have been reported: osteomyelitis, gangrene of both legs after obliteration of the arteries, suppurative phlebitis of the saphena, suppurative peri carditis, otitis media, meningitis, brain and lung abscesses, empyema, and thvreoiditis.
Gangrene of the skin may be observed in the course of any of the acute exanthematous diseases but in none so frequently as varicella. There is much concerning the process which is Obscure notwithstanding the fact that the gangrenous form has been known since 1S07 (Whitley Stokes), according to Hesse since 1691 (Gideon Harvey), and has been thoroughly studied by many observers. Doubtless underfed, cachectic and tuberculous children and especially those weakened by diseases (measles, whooping-cough, pneumonia and the like) are prone to gan grene, but sound healthy children may be affected as well.
The bacteriological investigations have not thrown much light upon the subject. Staphylococci and streptococci are the usual find; but virulent diphtheria bacilli have been noted in a case (A. Krjukoff, 1S99), and in Demme's case (1S92) the ulcerations were of a tuberculous char acter.
Gangrene may be noted in cases running an apparently normal course, as well as in those which from the beginning show either unusual or very severe symptoms. This complication generally occurs sporadi cally in an otherwise benign epidemic hut sometimes there are numer ous cases. Ileim (1809) reported that in some epidemics there was an especial tendency to gangrene. The gangrene may begin on the first. day (Edwards, 1903) or even as late as the drying up stage. It may affect only one spot or the majority of the papules.