Progressive claudication of the upper extremity is uncommon and can be misattributed to cervical radiculopathy or even shoulder pathology, such as tendonitis or bursitis. We report a patient presenting to the emergency department with several months of worsening left upper-extremity pain initially managed as suspected radiculopathy, but, in retrospect, was upper-extremity claudication. This was discovered through the presence of lesions beneath the fingernails of the left hand, splinter hemorrhages. A computed tomographic angiography (CTA) of the chest for aortic and vascular evaluation demonstrated a mural thrombus partially occluding the left subclavian artery. The patient was admitted for further management and observation. Following initiation of systemic anticoagulation, symptoms had significantly improved, and the patient was discharged home in stable condition. This case underscores the diagnostic importance of bedside examination and vascular imaging when evaluating atypical upper-extremity claudication. This also highlights arterial thrombus as a potentially reversible cause of upper-extremity pain when promptly recognized and treated.

Onychomatricoma is a rare benign tumor of the nail matrix that is often misdiagnosed due to its resemblance to other nail conditions, particularly onychomycosis. A giant variant, which affects the entire nail structure, is even more uncommon, with fewer than 20 cases documented. We present the case of a 62-year-old male with a 5-year history of a slow-growing, asymptomatic tumor on the third nail of his left hand. Clinical examination revealed a papillomatous mass originating from the nail matrix, accompanied by nail thickening and xanthonychia. Dermoscopy showed longitudinal yellow, white, and gray lines, splinter hemorrhages, and a honeycomb pattern. Mycological testing suggested onychomycosis, but due to the size and persistence of the lesion, a multidisciplinary team recommended a complete nail avulsion and proximal matricectomy. Histopathological analysis revealed fibroepithelial projections covered by squamous epithelium and thickened nail plate fragments, confirming the diagnosis of giant onychomatricoma. The patient underwent surgical management and has shown no signs of recurrence after 2 years of follow-up. This case highlights the diagnostic and therapeutic challenges posed by giant onychomatricoma, particularly when coexisting with fungal infection. It also underscores the need for thorough clinical, dermoscopic, and histopathological evaluation in cases of chronic nail deformities.

Rarely, recipients of adenoviral vector-based vaccines experience a severe thrombotic thrombocytopenic condition referred to as vaccine-induced immune thrombotic thrombocytopenia (VITT). VITT is a transient prothrombotic process, although recent data suggests that VITT anti-platelet factor 4 (PF4) antibodies are more persistent than antibodies seen in heparin-induced thrombocytopenia. Whether anti-PF4 antibody persistence in VITT is related to the continued persistence of antibody clones from the acute phase or the development of novel antibodies is unclear. To study this, acute and follow-up samples were obtained from six Ad26.COV2.S-associated VITT patients, with a median time to follow-up of 244 days from acute presentation (Range, 114-664 days). Upon affinity-enrichment of antibodies, mono/oligoclonal PF4/heparin-reactive anti-PF4 antibodies were observed despite negative results in serum protein electrophoresis and the more sensitive "Mass-Fix" technique. This finding distinguishes VITT from monoclonal gammopathy of thrombotic significance where monoclonal antibodies are observed in native sera. Anti-PF4 antibody abundance decreased over time, with no evidence of novel anti-PF4 antibody production after acute presentation. Although previous studies indicate a stereotypical pairing of VITT antibodies with lambda light chains, one VITT patient produced anti-PF4 antibodies with a kappa light chain, suggesting immunological heterogeneity. While none of these six antibodies caused long-term thrombocytopenia or thrombosis, platelet-activating anti-PF4 antibodies were seen four years after the acute event in an additional ChAdOx1 nCoV-19-associated VITT patient. These antibodies continued to cause chronic low-grade thrombocytopenia, highlighting the potential for long-term sequelae in what is generally viewed as a transient thrombotic thrombocytopenic syndrome.

Nail changes are often associated with systemic disease, and are sometimes one of the earliest clues. Nail examination is often overlooked in clinical practice, and there remains a significant gap in dermatology educational curricula on diagnosis and management of nail disorders. The purpose of this review is to describe salient nail signs which can provide clues to the physician for the diagnosis of a systemic disorder. In Part I of this two part continuing medical education series, we review changes in nail color and vasculature known to be associated with systemic disease. Prompt recognition of these signs on routine physical examination is important for suspecting underlying diseases and improving patient outcomes. We also describe clinical algorithms to approach these salient nail findings to help physicians perform appropriate workup or referral to physician specialists.

Infections of intracardiac thrombi are exceptionally rare but pose significant clinical risks, especially when located in the left atrial appendage (LAA). We present a unique case of a 51-year-old male with multiple comorbidities who was found to have an infected LAA thrombus causing persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia and systemic symptoms. Initial presentation included altered mental status, diabetic ketoacidosis, and classic signs of endocarditis such as splinter hemorrhages. Transesophageal echocardiogram imaging revealed a thrombus in the LAA, which was later confirmed to be infected and was acting as a nidus for sepsis. Surgical intervention and targeted antibiotic therapy led to clinical improvement. This case highlights the need for heightened clinical suspicion and a multidisciplinary approach when managing unexplained bacteremia, particularly in patients with known thrombotic risk factors. It also underscores the rare but significant potential for cardiac thrombi to become secondarily infected, warranting further study into diagnostic and therapeutic strategies.