What are the likely diagnoses for a 40-year-old female with a 3-month history of intermittent non-vertiginous dizziness, bilateral calf muscle aches, and weakness when standing or walking, with normal examination findings and no past medical history?

Likely Diagnosis: Lumbar Spinal Stenosis with Neurogenic Claudication

The clinical presentation of bilateral calf muscle aches and weakness occurring with standing from sitting and walking, relieved by sitting, in a 40-year-old female with normal neurological examination strongly suggests lumbar spinal stenosis with neurogenic claudication. 1

Key Diagnostic Features Supporting This Diagnosis

Characteristic Symptom Pattern

• Bilateral posterior lower limb pain with difficulty rising from sitting position is most strongly suggestive of lumbar spinal stenosis with neurogenic claudication 1
• The pain pattern worsens with standing or walking (spinal extension) and improves with sitting (spinal flexion), which is pathognomonic for neurogenic claudication 1, 2
• Difficulty rising from sitting or lying down strongly suggests mechanical spinal pathology rather than vascular claudication 1
• The 3-month duration of intermittent symptoms fits the typical presentation of spinal stenosis 1

Normal Examination Findings Are Compatible

• Normal cranial nerves, limb strength, sensation, and coordination do not exclude spinal stenosis, as neurological deficits may be absent or intermittent 1
• Negative Romberg's test and ability to walk tandem indicate preserved proprioception and cerebellar function, making central neurological causes less likely 3
• No postural blood pressure drop excludes orthostatic hypotension 3

Critical Differential Diagnoses to Exclude

Peripheral Artery Disease (PAD)

• Must obtain resting ankle-brachial index (ABI) bilaterally to definitively exclude vascular claudication 3, 2
• PAD claudication is induced by walking a predictable distance, worsens progressively with continued exercise, and resolves within 10 minutes of rest 3, 2
• The key distinguishing feature: spinal stenosis symptoms are relieved by lumbar flexion (sitting), while PAD requires only cessation of walking regardless of position 1, 2
• Bilateral calf symptoms can mimic PAD, making ABI testing mandatory 1, 2

Other Important Differentials

• Hip arthritis: Causes lateral hip/thigh aching that varies with activity but is not quickly relieved by position change and worsens with weight-bearing 3
• Restless legs syndrome: Characterized by urge to move legs with uncomfortable sensations that worsen at rest/evening and improve with movement 1
• Bilateral radiculopathy: Would typically show specific nerve root distribution patterns with dermatomal sensory or myotomal motor deficits 1
• Postural hypotension: Already excluded by normal orthostatic vital signs 3

Recommended Diagnostic Workup

Immediate Testing

1. Obtain resting ABI bilaterally to exclude PAD (ABI ≤0.90 confirms PAD) 3, 2
2. Complete neurological examination including straight-leg-raise testing, knee strength and reflexes, great toe and foot dorsiflexion strength, foot plantarflexion and ankle reflexes, and sensory distribution assessment 1
3. Assess weight distribution in sitting, standing, and walking to identify compensatory patterns 1

Imaging Considerations

• Do not routinely obtain imaging initially for nonspecific symptoms 1
• Obtain MRI if symptoms persist beyond 1 month of conservative management or if severe pain or progressive neurological deficits develop 1
• Anteroposterior pelvis and lateral spine radiographs initially, with MRI if surgical intervention is being considered 1

Initial Management Approach

Conservative Treatment (First-Line)

• Maintain physical activity and avoid bed rest 1
• Postural modifications: Encourage optimal spinal alignment with even weight distribution, avoid prolonged positioning at end-range joint positions, use pillows or furniture to support limbs when sitting or lying 3, 1
• Simple analgesics and NSAIDs for pain reduction 1
• Physical therapy emphasizing lumbar flexion exercises 2

Escalation if Symptoms Persist

• Multidisciplinary rehabilitation programs combining physical, vocational, and behavioral components 1
• Epidural steroid injections for refractory cases 2

Critical Clinical Pitfalls to Avoid

1. Do not assume vascular disease without ABI testing, as bilateral leg symptoms can mimic PAD but spinal stenosis is relieved by lumbar flexion rather than simple rest 1, 2
2. Do not overlook psychosocial factors such as depression, passive coping strategies, and job dissatisfaction, which predict poorer outcomes 1
3. Immediate specialist referral is required for bilateral motor weakness, saddle anesthesia, or urinary retention suggesting cauda equina syndrome 1
4. Avoid splinting or prolonged immobilization, as this leads to muscle deconditioning, increased pain, and learned non-use 3, 1