Author:
Editor(s):
Updated:
ULY CLINIC
ULY CLINIC
6 Julai 2025, 09:36:33
Hypoactive deep tendon reflex

A hypoactive deep tendon reflex (DTR) is a diminished or absent muscle response to tendon tapping. It may be graded as diminished (+) or absent (0). While symmetrical hypoactivity can be normal, asymmetrical or sudden-onset hypoactive DTRs are often pathological and indicate lower motor neuron or reflex arc disruption.
Understanding the Reflex Arc
Hypoactive DTRs suggest a problem within the reflex arc, including:
Afferent (sensory) nerve fibers
Spinal cord segment at the level of the reflex
Efferent (motor) nerve fibers
Neuromuscular junction
Target muscle
They often point to lower motor neuron (LMN) pathology, as opposed to upper motor neuron (UMN) lesions, which cause hyperreflexia.
History and Physical examination
After identifying hypoactive DTRs, assess:
History: Weakness, sensory loss, trauma, toxin exposure, infections, autoimmune conditions.
Medication use: Sedatives, muscle relaxants, neurotoxic drugs.
Neurologic exam: Evaluate tone, coordination, muscle bulk, and strength.
Gait and balance: Romberg’s test and heel-to-shin or finger-to-nose maneuvers.
Autonomic features: Look for bradycardia, bowel or bladder dysfunction.
Medical causes
Table: Causes of hypoactive deep tendon reflexes
Cause | Clinical Features | Special Considerations |
Guillain-Barré Syndrome (GBS) | Rapidly progressive ascending weakness, areflexia, paresthesia, autonomic dysfunction (e.g., fluctuating BP, tachycardia) | Medical emergency; monitor respiratory function and cardiac rhythm; IVIG or plasmapheresis required |
Botulism | Descending flaccid paralysis, blurred vision, diplopia, dysphagia, constipation, hypoactive bowel sounds | Notify public health; monitor for respiratory failure; antitoxin may be indicated |
Eaton-Lambert Syndrome | Proximal muscle weakness that improves with activity, hypoactive reflexes, autonomic symptoms | Often associated with small-cell lung carcinoma; EMG diagnostic; may respond to 3,4-DAP and cancer treatment |
Peripheral Neuropathy (e.g., diabetic, alcoholic) | Distal weakness, sensory loss (glove and stocking), paresthesia, hypoactive ankle reflexes | Tight glucose control (if diabetic); vitamin B1/B12 supplementation; fall risk assessment |
Polymyositis | Proximal muscle weakness, pain, stiffness, hypoactive or normal reflexes, elevated CK | Consider autoimmune screen; physical therapy and corticosteroids are mainstay |
Spinal Cord Lesions (acute phase) | Flaccid paralysis, areflexia below lesion, urinary retention, sensory loss, hypotension | Reflexes may return after spinal shock; neuroimaging essential; bladder/bowel care required |
Syringomyelia | Cape-like sensory loss (pain and temperature), hand muscle atrophy, areflexia in upper limbs | MRI diagnostic; may require surgical decompression; monitor for progression |
Friedreich’s Ataxia | Progressive ataxia, areflexia (esp. lower limbs), dysarthria, cardiomyopathy | Genetic testing confirms; multisystem involvement; supportive care for ataxia and cardiac issues |
Hypothyroidism | Fatigue, weight gain, cold intolerance, delayed reflexes, puffy face, bradycardia | Treat with levothyroxine; monitor reflex recovery over time |
Hypokalemia | Muscle cramps, weakness, arrhythmias, constipation, diminished reflexes | ECG monitoring; replace potassium; identify underlying cause (e.g., diuretics) |
Barbiturates & Sedatives | CNS depression, slurred speech, drowsiness, hyporeflexia | Monitor airway and consciousness; supportive care; consider antidotes if available |
Myasthenia Gravis | Fluctuating weakness, ptosis, diplopia; reflexes usually normal, may be diminished with disuse | Test for AChR antibodies; treat with pyridostigmine and immunosuppression |
Uremic Neuropathy | Burning feet, reduced vibration sense, distal weakness, hypoactive DTRs | Improve dialysis adequacy; symptom relief with gabapentinoids or tricyclics |
Spinal Muscular Atrophy (Pediatric) | Progressive weakness, absent reflexes, fasciculations (esp. tongue), hypotonia | Genetic diagnosis; supportive care, new therapies (e.g., nusinersen) may slow progression |
Muscular Dystrophy (Pediatric) | Gower’s sign, calf pseudohypertrophy, absent reflexes in later stages | Genetic counseling; monitor cardiac/respiratory status; steroids may slow progression |
Special considerations
Supportive care: Encourage movement, maintain muscle integrity through range-of-motion exercises, and prevent complications like DVT or pressure ulcers.
Safety: Provide assistive devices to reduce fall risk, ensure obstacle-free paths, and protect areas with sensory loss from burns or pressure injury.
Nutrition and hydration: Essential to support neuromuscular function.
Temperature and skin care: Regularly assess skin integrity and avoid extreme temperatures.
Psychosocial support: Educate caregivers and patients about adaptation strategies, especially in chronic or progressive conditions.
Pediatric consideration
Normal in infants; must be interpreted with developmental milestones.
Common in muscular dystrophy, spinal muscular atrophy, Friedreich’s ataxia, and syringomyelia.
Use distraction techniques to obtain accurate results in young children.
References
Born-Frontsberg E, Reincke M, Rump LC, Hahner S, Diederich S, Lorenz R, et al. Cardiovascular and cerebrovascular comorbidities of hypokalemic and normokalemic primary aldosteronism: Results of the German Conn’s Registry. J Clin Endocrinol Metab. 2009;94(4):1125–30.
Krantz MJ, Martin J, Stimmel B, Mehta D, Haigney MC. QTc interval screening in methadone treatment. Ann Intern Med. 2009;150:387–95.
Aminoff MJ, Greenberg DA, Simon RP. Clinical Neurology. 10th ed. New York: McGraw-Hill Education; 2019.
Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson JL, Loscalzo J. Harrison’s Principles of Internal Medicine. 20th ed. New York: McGraw-Hill Education; 2018.
McCance KL, Huether SE. Pathophysiology: The Biologic Basis for Disease in Adults and Children. 8th ed. St. Louis: Elsevier; 2019.
Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, editors. Nelson Textbook of Pediatrics. 21st ed. Philadelphia: Elsevier; 2020.
Darras BT, Jones HR, Ryan MM, De Vivo DC. Neuromuscular Disorders of Infancy, Childhood, and Adolescence: A Clinician's Approach. 2nd ed. London: Elsevier; 2015.