Inflammation of the splenic capsule is a more common affection than clinical observation would lead one to suppose. It consists of a more or less localized splenic peritonitis, and its lesions are often found at the necropsy when its existence had not been suspected during life.
ETIOLOGY.—Its commonest cause is the extension of inflammation from neighboring parts. Chronic ulcer of the stomach may be the origin of chronic perisplenitis, leading to the formation of dense inflammatory deposits. Persons who have long suffered from miasmatic poisoning frequently develop strong adhesions between the spleen and diaphragm. And from the same cause the spleen may become closely adherent to the neighboring viscera. Chronic enteritis, perinephritic inflammation, and the like may excite it. It has been shown that the pain in splenic affections is nearly always due to the capsulitis present; and it is probable that much pain in the splenic region, stitches in the side, etc. are really the results of this inflammation. It can only be conjectured that in given cases one has to do with perisplenitis. Almost all that is known about it comes from the dead-house.
PATHOLOGICAL ANATOMY.—The simplest post-mortem signs of bygone perisplenitis are the unusually dense fibrous adhesions between the spleen and surrounding parts. These may vary within wide limits. Exceptionally, the spleen will be found intimately adherent to surrounding parts throughout, and can only be separated from them by tearing it away. Under these circumstances, mostly in chronic malarial subjects, the capsule will be uniformly much thickened and sac-like. The splenic tissue may be reduced to a tarry, semi-fluid pulp that oozes through the lacerated walls. Sometimes the capsule of the spleen will show localized thickenings of dense cartilage-like consistency, usually on the convex surface. According to Wilks and Moxon (p. 487), "section shows them to be laminated parallel to the surface, and the microscope reveals a fibrinous structure, the fibres being arranged in dense areolated lamellæ." The same authors consider these to be among the most decisive evidences of chronic alcoholism. They may become calcified (Orth). It is not unlikely that they may often be the effects of syphilis. They undoubtedly often occur in syphilitic subjects. The interest attaching to them is entirely a pathological one, as the affection is never detected during life, and as they probably exert no influence whatever upon the duration of life or even upon the well-being of their bearer.
Lardaceous Spleen.
The spleen is more liable to lardaceous or amyloid disease than any other organ of the body. And, although in the further course of the degeneration other organs and tissues inevitably become implicated (unless the patient die of some intercurrent affection), the spleen may in the earlier stages be alone involved. In 58 cases of lardaceous disease compiled from the records of the London Hospital, the spleen was the only organ in which the degeneration was detected in 28 cases, while it remained unaffected in only 10 cases.10
10 Turner, Transactions Patholog. Soc. Lond., vol. xxx.
The tendency of lardaceous disease toward generalization shows that it is under systemic and not local influence, though whether this influence is exerted in depositing preformed albuminoid material in the affected parts (infiltration), or in bringing about a special alteration in situ (degeneration), is even yet not definitely decided. Upon the one hand, the infiltration theory is upheld by Rindfleisch, Billroth, and others, while Fehr, Kyber, Cohnheim, and others consider it to be a result of tissue-metamorphosis. Cohnheim concludes that the infiltration theory could only be accepted upon the presumption that the lardaceous material is not a soluble but a corpuscular substance, or that it is only deposited in consequence of some acquired predisposition of the part. He regards the process as a local degeneration due to general causes in which the lardaceous material is derived from the pre-existing albumen of the tissues. According to Virchow and Kyber, there is brought to the tissue whose nutrition is somehow lowered a substance, between which and a malarial substance formed in loco an intimate combination occurs, the result being lardaceous material (Ziegler).
This form of degeneration involves the spleen in one or both of two ways. It may appear as scattered points throughout the splenic substance, corresponding to the Malpighian bodies and presenting a resemblance to grains of boiled sago, or in a diffused manner, constituting true lardaceous spleen, in which the entire organ appears to be involved.
ETIOLOGY.—As in lardaceous disease of other parts, by far the most common causes of its development in the spleen are prolonged suppuration, especially of bone, the suppurative processes of phthisis pulmonalis and of scrofulosis. The next most frequent causative influence is syphilis, whether accompanied by prolonged suppuration or by the cachexia so often observed in this disorder. Chronic malarial poisoning, chronic diarrhoea, chronic alcoholism, and occasionally the less-rapidly fatal malignant new growths, may induce the degeneration. Exceptionally, it has been observed where no other general disturbance of nutrition had existed. The various causes of lardaceous degeneration have in common one feature, chronicity, though Mosler quotes from Cohnheim instances where lardaceous spleen was discovered in one case five months after joint injuries had been received, and in another four months after a compound fracture of the right leg.