Tuberculosis (TB): This is often considered a leading cause due to its classic presentation of weight loss, night sweats, fever, and cough. The global prevalence of TB and its potential for severe morbidity if untreated make it a prime consideration.

Lymphoma: Both Hodgkin's and non-Hodgkin's lymphoma can present with systemic symptoms such as weight loss and night sweats, making them a common consideration in patients with these symptoms.
Chronic Infections (e.g., Endocarditis, Osteomyelitis): Chronic infections can cause prolonged fever, night sweats, and weight loss due to the body's ongoing inflammatory response.
HIV/AIDS: Early stages of HIV infection can be asymptomatic, but as the disease progresses, patients may experience weight loss and night sweats among other symptoms.
Hyperthyroidism: Although more commonly associated with heat intolerance and weight loss despite increased appetite, hyperthyroidism can occasionally present with night sweats.

Malignancies (e.g., Lung, Breast, Colon Cancer): Various cancers can present with weight loss and night sweats, especially if they have metastasized. Missing a diagnosis of cancer can lead to delayed treatment and poor outcomes.
Pulmonary Embolism: While less commonly associated with night sweats, pulmonary embolism is a life-threatening condition that requires immediate diagnosis and treatment.
Sepsis: Sepsis, particularly when caused by certain bacteria, can present with fever, chills, and night sweats. It is critical to identify and treat sepsis promptly to prevent high mortality.

Pheochromocytoma: A rare tumor of the adrenal gland that can cause episodic hypertension, sweating (including night sweats), and weight loss.
Whipple's Disease: A rare, systemic bacterial infection that can cause weight loss, diarrhea, joint pains, and night sweats.
Brucellosis: A zoonotic infection that can present with fever, night sweats, and weight loss, among other symptoms, and is more common in individuals who work with animals or consume unpasteurized dairy products.