Differential Diagnosis

Given the statement "But it's only just started happening," we can infer that the patient is experiencing a new onset of symptoms. The differential diagnosis can be organized into the following categories:

• Single Most Likely Diagnosis:
  • Acute Viral Illness: This is often the most common cause of new onset symptoms, especially if the patient has been exposed to someone with a similar illness or during viral season. The sudden onset of symptoms such as fever, cough, sore throat, or gastrointestinal issues could point towards a viral etiology.
• Other Likely Diagnoses:
  • Allergic Reaction: A new exposure to an allergen could result in symptoms that have just started happening, such as hives, itching, swelling, or respiratory issues.
  • Medication Side Effect: Starting a new medication can lead to side effects that the patient has not experienced before, ranging from mild (e.g., nausea, dizziness) to severe (e.g., anaphylaxis, Stevens-Johnson syndrome).
  • Stress or Anxiety: Psychological factors can manifest physically, and a recent increase in stress or anxiety could lead to new symptoms like palpitations, tremors, or gastrointestinal disturbances.
• Do Not Miss Diagnoses:
  • Myocardial Infarction (MI) or Acute Coronary Syndrome: Although less common, new onset chest pain or discomfort, especially if accompanied by other symptoms like shortness of breath, nausea, or arm pain, could indicate an MI, which is a medical emergency.
  • Pulmonary Embolism (PE): Sudden onset of dyspnea, chest pain, or cough could be indicative of a PE, which requires immediate medical attention.
  • Stroke or Transient Ischemic Attack (TIA): New neurological deficits, such as weakness, numbness, vision changes, or difficulty speaking, could signal a stroke or TIA, necessitating urgent evaluation.
• Rare Diagnoses:
  • Endocrine Disorders: Conditions like thyroid storm, adrenal crisis, or pheochromocytoma can present with sudden onset of symptoms, though they are less common.
  • Autoimmune Disorders: Certain autoimmune diseases, such as lupus or rheumatoid arthritis, can have a sudden onset, though this is less typical and usually follows a more insidious course.
  • Neurological Conditions: Diseases like multiple sclerosis, Guillain-Barré syndrome, or acute disseminated encephalomyelitis can present with new neurological symptoms, but these are relatively rare.