**6. Extremities and musculoskeletal system**

In general terms, extremity involvement in association with IE represents approximately onethird of all cases of SE, with clinical manifestations involving the musculature in approximately 40% cases and bones/joints in >10% of instances [10, 110]. Other than massive embolic events involving acute occlusion of arterial flow to an extremity producing significant ischemia, symptoms tend to be more "nebulous" in terms of clinical presentation, more self-limited in nature, and easily overlooked by clinicians [10, 100]. Pathognomonic signs such as Osler nodes

**Figure 4.** (A, left) An example of an Osler node in a patient with infective endocarditis (source: Ref. [112], image used in accordance with the terms of the CC BY 4.0 License); (B, right) Janeway lesions (see arrows) in a patient with aortic valve vegetation (source: Ref. [113], image used under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License).

and Janeway lesions are rare (2.7 and 1.6% cases, respectively) but highly suggestive of endocarditis [111]. **Figure 4A** shows an example of an Osler node, while **Figure 4B** demonstrates a Janeway lesion [112, 113].

#### **6.1. Acute extremity ischemia**

bowel appears to be less commonly affected (e.g., superior mesenteric artery in 3%, inferior mesenteric in <1%) [103]. This may be, at least in part, due to the presence of some degree of redundancy within the mesenteric vasculature, as opposed to a lack of such redundancy in the kidney or spleen. Occlusion of the superior mesenteric artery by SE is relatively well described in the setting of mitral valve endocarditis [104]. Mesenteric pseudoaneurysm attributable to SE has also been described [105]. In cases of acute arterial occlusion, bowel infarction may follow without prompt restoration of adequate blood flow to the involved segment(s) of

casts

**Table 2.** Types of kidney injury, including their associated differentiating characteristics [102].

Remove inciting substance

**Glomerular Interstitial Tubular Vascular**

Antibiotics Sepsis and hypovolemia Renal ischemia

Hydration and treatment of underlying condition

Granular casts Tubular epithelial cell casts

> Surgical correction of underlying pathology

The involvement of reproductive organs in septic embolic complications is very uncommon. However, the authors believe that at least a brief overview of this under-recognized topic is warranted. In terms of testicular involvement, symptomatic presentation, including swelling, has been reported in conjunction with right-sided endocarditis [107]. It is thought that the this unusual clinical picture may result from SE [52, 107]. In another case, pneumococcal pulmonary valve endocarditis has been circumstantially linked to epididymo-orchitis and a scrotal abscess [108], although the directionality of causation may be difficult to prove except for the fact that *Streptococcus pneumoniae* isolated from the epididymo-orchitis is seldom a primary cause of scrotal infection. Equally uncommon, ovarian involvement has also been reported. In an exceedingly rare case, a female patient presented with a giant pyomyoma suggestive of ovarian neoplasm [109]. The origin of this presentation, however, was traced to *Streptococcus agalactiae* endocarditis and deep vein thrombosis of the right external iliac and

In general terms, extremity involvement in association with IE represents approximately onethird of all cases of SE, with clinical manifestations involving the musculature in approximately 40% cases and bones/joints in >10% of instances [10, 110]. Other than massive embolic events involving acute occlusion of arterial flow to an extremity producing significant ischemia, symptoms tend to be more "nebulous" in terms of clinical presentation, more self-limited in nature, and easily overlooked by clinicians [10, 100]. Pathognomonic signs such as Osler nodes

bowel [106].

**Type of kidney injury**

158 Advanced Concepts in Endocarditis

Clinical management

Typical causes Bacterial endocarditis

and vasculitis

Treatment of underlying etiology

Cast type Red blood cell casts White blood cell

**5.6. Reproductive organs**

femoral veins [109].

**6. Extremities and musculoskeletal system**

This potentially devastating presentation has been reported in the setting of more severe cases of IE, often involving valve replacement [114–116], with some patients experience multiple/ recurring embolic events [114, 115]. In terms of clinical presentation, patients may exhibit a broad spectrum of complaints including pain, pallor, poikilothermia, and paresthesias with extreme cases threatening the viability of the limb itself [114]. Both surgical and thrombolytic management options have been reported [117, 118]. Prompt recognition of the cardiac source of SE is critical in preventing further embolic events.

#### **6.2. Septic arthritis**

Due to their non-specific nature and general commonality, joint-related complaints can be challenging to diagnose and easily misinterpreted. Not infrequently, multiple diagnostic tools must be utilized to successfully identify the cardiac source of the patient's original symptoms (and thus the proximal source of infection) [119]. In one case, it was the complaint of septic arthritis which led to the ultimate diagnosis of streptococcal endocarditis [120]. Similar to other embolic phenomena associated with IE, septic arthritis tends to be a manifestation of multi-focal metastases of infectious material [119, 121].
