Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that causes joint inflammation, erosion, and deformity. The prevalence of RA in North America is 0.5% to 1%. RA is associated with significant morbidity and disability and an increased mortality rate. The disease should be suspected in patients who present with joint inflammation, especially those who have polyarthritis. Additional characteristic features include symmetrical small joint polyarthritis, morning stiffness, and constitutional symptoms. Extra-articular manifestations are common and may affect multiple body systems. Application of a decision tool, such as the Leiden clinical prediction rule for undifferentiated arthritis, may facilitate early diagnosis of RA. Useful diagnostic tests include inflammatory markers such as C-reactive protein, rheumatoid factor, and anti-cyclic citrullinated peptide antibody. Initial therapy routinely includes oral methotrexate. The American College of Rheumatology and European Alliance of Associations for Rheumatology recommend a treat-to-target approach, including rapid interventions to reduce disease activity and achieve remission. Although RA remains incurable, patient quality of life has improved dramatically with biologic disease-modifying antirheumatic drugs (DMARDs) and targeted synthetic DMARDs. All DMARDs increase the risk of infection; therefore, routine vaccinations should be up to date in patients taking these drugs. Because patients with RA have increased risk of cardiovascular disease, addressing other cardiovascular risk factors may reduce morbidity and mortality.

Easy bruising and bleeding are commonly seen in primary care. Use of a bleeding assessment tool and a comprehensive history, physical examination, and patient-provided photographs can help identify causes of abnormal bleeding and bruising. Family history can aid diagnosis of a heritable cause. Nonaccidental trauma should be considered, especially in vulnerable populations. Initial laboratory testing includes a complete blood cell count, peripheral blood smear, prothrombin time (PT), international normalized ratio, activated partial thromboplastin time (aPTT), and fibrinogen. Normal PT and aPTT results may indicate a platelet disorder. A normal PT result with a prolonged aPTT result indicates a disorder of the intrinsic coagulation pathway, and a prolonged PT result with a normal aPTT result may indicate a disorder of the extrinsic coagulation pathway. Consultation with a hematologist is recommended when initial evaluation indicates a bleeding disorder or when suspicion remains high despite a normal laboratory workup result.

Tongue conditions occur in 15.5% of the US population. The most common tongue conditions are geographic tongue, fissured tongue, and black hairy tongue; these conditions do not require treatment. Median rhomboid glossitis can be associated with a candidal infection; symptomatic lesions usually improve with use of antifungals. Atrophic glossitis is often linked to a nutritional deficiency and resolves with treatment of the underlying condition. Oral hairy leukoplakia is caused by Epstein-Barr virus and most often presents in patients with severely compromised immunity; it can be treated with oral antivirals. Growths of the tongue usually require biopsy to differentiate benign lesions (eg, traumatic fibromas, squamous cell papillomas) from leukoplakia and squamous cell carcinoma. Referral to an oral and maxillofacial surgeon, otolaryngologist, or a dentist experienced in oral pathology may be indicated. Burning mouth syndrome often involves the tongue, and if it does not resolve spontaneously, studies have shown improvement with gabapentin, topical clonazepam, capsaicin, and cognitive behavior therapy. Oral lichen planus is a chronic inflammatory disorder that can affect the tongue and is best treated with topical or systemic corticosteroids and calcineurin inhibitors. There is a lack of consensus on the definition and treatment of ankyloglossia (tongue-tie); however, some evidence supports that frenotomy can improve breastfeeding and decrease lactation-associated nipple pain.

Genital herpes is a sexually transmitted infection caused by herpes simplex virus (HSV) type 1 or 2. It affects at least 500 million people worldwide and is a lifelong condition involving initial infection and periodic reactivation with variable viral shedding. There are no vaccinations for the prevention of HSV, and routine serologic screening is not recommended in asymptomatic individuals. Practices that prevent or reduce transmission include the use of suppressive antiviral therapy in serodiscordant partners, avoiding sexual contact during outbreaks, and use of condoms. A clinically apparent herpes outbreak is characterized by painful vesicles on the genitals, rectum, or perineum and may be accompanied by a flulike syndrome of fever, malaise, and lymphadenopathy. Diagnosis uses type-specific polymerase chain reaction, viral culture of active lesions, or type-specific serologic testing. Nucleoside analogue medications reduce viral shedding and are used to treat active outbreaks and prevent recurrences. Complications of genital herpes include encephalitis, meningitis, and urinary retention. During pregnancy, antiviral suppression is recommended starting at 36 weeks of gestation in patients with a known history of genital herpes. Elective cesarean delivery should be offered to patients with active lesions to reduce neonatal exposure to HSV.

Prostate cancer is the most diagnosed noncutaneous malignancy and the second most common cause of cancer death among men in the United States. Risk factors include older age, family history of prostate cancer, and Black race. Screening via prostate-specific antigen testing may lead to a small reduction in prostate cancer-specific mortality, with no reduction in all-cause mortality, but it can cause significant harms related to false-positive test results, unnecessary biopsies, overdiagnosis, and overtreatment. Shared decision-making is strongly recommended by all national guidelines before initiating screening. Most guidelines recommend screening every 2 to 4 years in men 55 to 69 years of age at average risk. After a positive prostate-specific antigen test result (more than 4 ng/mL), the test should be repeated. If the prostate-specific antigen level is still elevated, next steps include multiparametric magnetic resonance imaging, assessment of urine or blood biomarkers, and referral to urology. Active surveillance is increasingly accepted as the preferred standard of care for patients with newly diagnosed low-risk prostate cancer, because it is associated with similar long-term survival and better quality of life than curative treatment. The primary intent of screening is to identify patients with clinically significant prostate cancer who may benefit from curative treatment while minimizing the detection of clinically insignificant cancer.

Diabetic ketoacidosis (DKA) is a life-threatening complication of type 1 and type 2 diabetes resulting from an absolute or relative insulin deficiency. It can occur in patients of all ages and can be the initial presentation of diabetes, especially in young children. Polyuria and polydipsia are the most common symptoms, followed by nausea, vomiting, abdominal pain, weight loss, severe fatigue, dyspnea, and preceding febrile illness. Traditionally, DKA has been diagnosed by the triad of hyperglycemia (blood glucose greater than 250 mg/dL), metabolic acidosis (pH less than 7.3, serum bicarbonate less than 18 mEq/L, anion gap greater than 10 mEq/L), and elevated serum (preferred) or urine ketones. However, hyperglycemia has been de-emphasized in recent guidelines because of the increasing incidence of euglycemic DKA. The use of sodium-glucose cotransporter-2 inhibitors modestly increases the risk of DKA and euglycemic DKA. Electrolytes, phosphate, blood urea nitrogen, creatinine, urinalysis, complete blood cell count with differential, A1C, and electrocardiography should be evaluated for all patients diagnosed with DKA to identify causes and complications of DKA. Amylase, lipase, hepatic transaminase levels, troponin, creatine kinase, blood and urine cultures, and chest radiography are additional tests to consider. Treatment involves fluid and electrolyte replacement, insulin, treatment of precipitating causes, and close monitoring to adjust therapy and identify complications. Prevention strategies include identifying diabetes before DKA develops, educating patients to manage high-risk situations, and ensuring uninterrupted access to therapies for diabetes.