Differential Diagnosis for Stiff Neck, Leg Pain, Fever, and Headache in Children

Single Most Likely Diagnosis

• Viral Meningitis: This is a common cause of stiff neck, fever, and headache in children. The presence of leg pain could be due to viral myositis or irritation of the nerve roots. Viral meningitis is often self-limiting but requires differentiation from bacterial meningitis.

Other Likely Diagnoses

• Bacterial Meningitis: Although less common than viral meningitis, bacterial meningitis is a critical diagnosis to consider due to its high morbidity and mortality if not treated promptly. Symptoms can include stiff neck, fever, headache, and sometimes leg pain due to meningismus or systemic infection.
• Osteomyelitis or Septic Arthritis: These conditions can cause leg pain and fever. If the infection spreads or affects the spine, it could also lead to stiff neck and headache.
• Influenza or Other Viral Infections: Influenza and other viral infections can cause fever, headache, leg pain (myalgia), and sometimes stiff neck due to muscle spasms or viral meningitis.

Do Not Miss Diagnoses

• Subarachnoid Hemorrhage: Although rare in children, a subarachnoid hemorrhage can present with sudden onset of headache, stiff neck, and sometimes fever if there is associated infection or inflammation. It is crucial to diagnose promptly due to its high mortality rate.
• Meningococcemia: This is a severe infection caused by Neisseria meningitidis, which can lead to meningitis, sepsis, and death if not treated immediately. Early signs can include fever, headache, stiff neck, and a rash.
• Spinal Epidural Abscess: This condition is a medical emergency that can cause fever, headache, stiff neck, and leg pain due to compression of the spinal cord. Prompt diagnosis and treatment are necessary to prevent neurological damage or death.

Rare Diagnoses

• Lyme Disease: In endemic areas, Lyme disease can cause a range of symptoms including fever, headache, stiff neck, and leg pain (due to arthritis). It's less common but should be considered in children who spend time outdoors.
• Leptospirosis: This bacterial infection can cause fever, headache, stiff neck, and leg pain. It's more common in children who are exposed to contaminated water or soil.
• Tuberculous Meningitis: Although rare in many parts of the world, tuberculous meningitis can present with chronic symptoms of headache, stiff neck, and fever. It's an important consideration in endemic areas or in children with compromised immune systems.