The cause of gait disturbances may be minor (e.g., stone in a shoe) or serious (e.g., neurological damage). In a number of cases, a characteristic gait disturbance may be the first sign that a condition presents. Abnormalities or injuries of the nervous system, back, lower limb or abdomen may cause difficulty walking.

Gait disturbances often result from leg pain, knee pain, foot pain or back pain. The location of pain may not reflect the location of the injury or abnormality, so a problem in the hip may cause pain in the knee. Many causes of gait disturbances are structural issues with the bones and/or joints. These issues typically result in a variety of different forms of pain. When this pain occurs with or is made worse by walking, the gait is altered to compensate. In fact, any pain in weight-bearing structures of the body (e.g., feet, legs, knees, hips) may result in compensation by altering the gait. This may range from injuries (e.g., jammed toe, sprained ankle, leg fracture) to medical illnesses and conditions. Such conditions may include:

• Arthritis and other inflammatory or degenerative conditions. These may cause pain and decreased mobility of a joint, causing gait disturbance. Acute and chronic arthritis may affect the hip, knee, ankle, foot or spinal joints and cause a disturbance in gait. Rheumatoid arthritis, infectious arthritis, osteoarthritis, gout and pseudogout are common causes of limp.
  
  Inflammation in structures other than the joints may also result in a gait disturbance. These include inflammation of the fluid sac lubricating the joints (synovitis), muscles (myositis), tendons (tendinitis), bursa (bursitis) or fascia (for example, plantar fasciitis).

Many overuse injuries, such as those sustained in athletics, can disrupt gait, including shin splints, Osgood-Schlatter disease, iliotibial band syndrome, patellofemoral syndrome, patellar tendinopathy, plica syndrome or a damaged Achilles tendon or knee ligament or meniscus.

Degenerative conditions include osteochondroses (degenerative changes in bone formation during periods of rapid growth) and osteonecrosis (lack of blood supply to the bone causes tissue to die).

• Infections. These include discitis, an infection of an intervertebral disc (disc that sits between the vertebrae to cushion them). This may cause severe pain and gait disturbances.  Also, trauma or infection (e.g., osteomyelitis) in the feet, legs or joints can cause a gait disturbance.
  

• Musculoskeletal deformity. An example is tarsal coalition, where fibrous bony connection forms between two or more tarsals (long bones in the foot). This is present at birth but is typically only noticed after the age of 10 years, when the coalitions (connections) ossify (turn into bone). Motion in the foot is limited and pain is produced. The pain worsens with activity (e.g., walking on uneven ground, running) and typically results in a limp. Other examples of deformities include clubfoot, leg-length discrepancy, congenital hip dislocation and scoliosis.
  
  
• Appendicitis. Inflammation of the appendix. In some cases, this may cause acute pain that may irritate a muscle that leads toward the leg. This pain radiating down the leg may cause the patient to limp.
  
  
• Tumors. Tumors, both benign (e.g., osteoid osteoma) and malignant (e.g., leukemia), may cause a variety of gait disturbances.
  
  
• Other conditions that may cause a gait disturbance include:
  
  
• Rheumatic fever
• Serum sickness
• Developmental dysplasia of the hip
• Hemarthrosis (blood accumulation in the joint)
• Lyme disease
• Sickle cell anemia
• Systemic lupus erythematosus
• Other sources of lower-body joint pain

Many gait disturbances result from neurological problems. These may occur in the brain, spinal cord, or peripheral nerves. When these nerves are affected, muscle coordination may be impaired, resulting in an abnormal gait.

Among the neurological causes of gait disturbances are chronic, progressive neurological disorders such as Parkinson’s disease, muscular dystrophy, multiple sclerosis, amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig’s disease), post-polio syndrome and Huntington’s chorea. Impaired gait can also indicate Alzheimer’s disease or other dementias.

Other neurological causes include:

• Cervical spinal stenosis. A narrowing of the spinal canal in the neck that can cause pressure on the brain in the back of the skull. This may result in a spastic or ataxic gait.
  
  
• Cerebral palsy. Brain damage typically occurring before birth and resulting in muscular impairment. This may result in a variety of gait disturbances.
  
  
• Stroke. A life-threatening event in which a part of the brain is deprived of sufficient oxygen. Stroke often causes weakness or paralysis on one side of the body and results in a hemiplegic gait.
  
  
• Dizziness, vertigo, Meniere’s disease, cerebellar dysfunction or decreased sensations in the feet. Patients with any of these conditions tend to have a wide gait, which means putting the feet more outside the body’s midline than usual.
  
  
• Peripheral neuropathy. For example, diabetic neuropathy is a common cause of foot problems and may cause a disabling deformity known as Charcot foot. Neuropathies can also be due to conditions ranging from trauma to alcoholism.
  
  
• Nerve impingement in the lower back. For example, sciatica, which may be due to a herniated disc, degenerative disc disease or spinal stenosis,  can cause weakness in legs, leading to a gait disturbance.
  
  
• Complex regional pain syndrome. This chronic condition encompasses two disorders formerly known as reflex sympathetic dystrophy syndrome and causalgia. It usually occurs after a trauma to an arm or a leg and is characterized by burning or aching pain along with inflammation, skin discoloration, altered temperature, abnormal sweating and hypersensitivity of the affected area.
  
  
• Charcot-Marie-Tooth disease (CMT). Though little known to the general public, CMT is one of the more common inherited nerve conditions. Also known as hereditary motor and sensory neuropathy (HMSN) and peroneal muscular atrophy, CMT impairs peripheral nerves and may result in foot drop, high-stepping gait or deformities of the foot.
  
  
• Medications. The drugs most associated with gait disturbances are neuroleptics. Long-term use of neuroleptics, usually prescribed for psychiatric disorders and sometimes for neurological or gastrointestinal conditions, can cause tardive dyskinesia (difficulty in performing voluntary movements).