Hold your horses! Before you wade into the Visceral Disorders Section, please read Dr. Nansel & Szlazak's fascinating JMPT article (see below), as it clarifies WHY chiropractic gets such dramatic results with a spectrum of purported diseases and disorders. You'll be glad you did!
Somatic Dysfunction and the Phenomenon of Visceral Disease Simulation:
A Probable Explanation for the Apparent Effectiveness of Somatic Therapy
in Patients Presumed to be Suffering from True Visceral Disease
J Manipulative Physiol Ther 1995 (Jul); 18 (6): 379–397 ~ FULL TEXT
The proper differential diagnosis of somatic vs. visceral dysfunction represents a challenge for both the medical and chiropractic physician. The afferent convergence mechanisms, which can create signs and symptoms that are virtually indistinguishable with respect to their somatic vs. visceral etiologies, need to be appreciated by all portal-of-entry health care providers, to insure timely referral of patients to the health specialist appropriate to their condition. Furthermore, it is not unreasonable that this somatic visceral-disease mimicry could very well account for the “cures” of presumed organ disease that have been observed over the years in response to various somatic therapies (e.g., spinal manipulation, acupuncture, Rolfing, Qi Gong, etc.) and may represent a common phenomenon that has led to “holistic” health care claims on the part of such clinical disciplines.
Clinical Effectiveness Of Manual Therapy For The Management Of
Musculoskeletal And Non-Musculoskeletal Conditions: Systematic
Review And Update Of UK Evidence Report
Chiropractic & Manual Therapies 2014 (Mar 28); 22 (1): 12 ~ FULL TEXT
25,539 records were found; 178 new and additional studies were identified, of which 72 were systematic reviews, 96 were randomised controlled trials, and 10 were non-randomised primary studies. Most 'inconclusive' or 'moderate' evidence ratings of the UK evidence report were confirmed. Evidence ratings changed in a positive direction from inconclusive to moderate evidence ratings in only three cases (manipulation/mobilisation [with exercise] for rotator cuff disorder; spinal mobilisation for cervicogenic headache; and mobilisation for miscellaneous headache). In addition, evidence was identified on a large number of non-musculoskeletal conditions not previously considered; most of this evidence was rated as inconclusive.
Visceral Responses to Spinal Manipulation
J Electromyogr Kinesiol. 2012 (Oct); 22 (5): 777–784 ~ FULL TEXT
While spinal manipulation is widely seen as a reasonable treatment option for biomechanical disorders of the spine, such as neck pain and low back pain, the use of spinal manipulation to treat non-musculoskeletal complaints remains controversial. This controversy is due in part to the perception that there is no robust neurobiological rationale to justify using a biomechanical treatment of the spine to address a disorder of visceral function. This paper therefore looks at the physiological evidence that spinal manipulation can impact visceral function. A structured search was conducted, using PubMed and the Index to Chiropractic Literature, to construct of corpus of primary data studies in healthy human subjects of the effects of spinal manipulation on visceral function. The corpus of literature is not large, and the greatest number of papers concerns cardiovascular function. Authors often attribute visceral effects of spinal manipulation to somato-autonomic reflexes. While this is not unreasonable, little attention is paid to alternative mechanisms such as somato-humoural pathways. Thus, while the literature confirms that mechanical stimulation of the spine modulates some organ functions in some cohorts, a comprehensive neurobiological rationale for this general phenomenon has yet to appear.
Enhancement of In Vitro Interleukin-2 Production in Normal Subjects
Following a Single Spinal Manipulative Treatment
Chiropractic & Osteopathy 2008 (May 28); 16: 5 ~ FULL TEXT
The present study demonstrates that, the in vitro T lymphocyte response to a conventional mitogen (SPA), as measured by IL-2 synthesis, can become enhanced following SMT. Furthermore, within a period of time following the manipulative intervention, this effect may be independent of joint cavitation. Thus the results of this study suggest that, under certain physiological conditions, SMT might influence IL-2-regulated biological responses.
Chiropractic Care for Nonmusculoskeletal Conditions: A Systematic
Review With Implications For Whole Systems Research
J Altern Complement Med. 2007 (Jun); 13 (5): 491–512 ~ FULL TEXT
(1) Adverse effects should be routinely reported. For the few studies that did report, adverse effects of spinal manipulation for all ages and conditions were rare, transient, and not severe. (2) Evidence from controlled studies and usual practice supports chiropractic care (the entire clinical encounter) as providing benefit to patients with asthma, cervicogenic vertigo, and infantile colic. Evidence was promising for potential benefit of manual procedures for children with otitis media and elderly patients with pneumonia.
The Somantovisceral Reflex: How Important for the "Type O" Condition?
Chiropractic Journal of Australia 2004 (Sep); 34 (3): 97–102
Spinal manipulative therapy can affect the resting status of somatic structures via mechanical and neurological (somato-somatic reflex) mechanisms, and this change can cause a change to the afferent arm of the somato-visceral reflex. It is likely that supraspinal influences play a major role in this effect, however the exact nature of this effect has not been demonstrated with respect to manipulation of the spine. Much research is required to establish a causative relationship between the treatment of somatic structures of the spine and normalisation of pathological visceral tissues via somatovisceral or supraspinal reflexes.
The Reflex Effects of Subluxation: The Autonomic Nervous System
J Manipulative Physiol Ther 2000 (Feb); 23 (2): 104–106 ~ FULL TEXT
There is no shortage of theories to explain the role of subluxation in disease and the effect of adjustment in relieving symptoms. The autonomic nervous system has often been invoked in constructing mechanisms to account for the effects of spinal dysfunction; recent investigations justify the attention that has been focused on this component of the nervous system. Recent neuroscience research supports a neurophysiologie rationale for the concept that aberrant stimulation of spinal or paraspinal structures may lead to segmentally organized reflex responses of the autonomic nervous system, which in turn may alter visceral function.
Physiological Regulation Through Manual Therapy
Physical Medicine and Rehabilitation: State of the Art Reviews 2000; 14 (1)
Manual therapy can be divided into two distinct conceptual approaches to treatment: specific adjustments for correction of anatomic issues (structure) and adjustments for physiologic regulation (function). In recent years, the primary emphasis of most practitioners has been on finding structural problems associated with musculoskeletal issues and correcting anatomic findings ("lesions" and "subluxations"). Less emphasized has been the capability for manual therapy to regulate physiology, reestablishing equilibrium and balance among the various systems and processes of the body. Historically, however, the origins of both osteopathy and chiropractic can be traced to positive outcomes in the treatment of systemic dysfunction. A. T. Still, founder of osteopathy, used an "inhibition" technique (lying with his head in a sling) to relieve his own headaches; D. D. Palmer, founder of chiropractic, first treated a patient with a hearing impairment.
Unexpected Positive Nonmusculoskeletal Side Effects of Chiropractic Care
J Manipulative Physiol Ther 1999 (Nov); 22 (9): 559–564 ~ FULL TEXT
A retrospective study conducted in Sweden  has determined that about one in four chiropractic patients experiences some form of "positive nonmusculoskeletal side effect" after spinal manipulative therapy (SMT). In addition, the percentage of patients who experience positive side effects increases with the number of spinal regions adjusted. The Swedish researchers asked all members of the Swedish Chiropractors Association (SCA) to participate in the study. Eighty-one percent of the SCA membership complied. Each doctor of chiropractic gathered data from 20 patients over a three-week period for a total of 1,504 valid patient questionnaires. Patients were included if they had been previously adjusted within the last two weeks for musculoskeletal complaints. The patients were asked if after their previous visit they ěexperienced any positive changes that do not seem to have anything to do with your back problem?
The Reflex Effects of Spinal Somatic Nerve Stimulation on Visceral Function
J Manipulative Physiol Ther 1992 (Jan); 15 (1): 57–61
This paper studies somatovisceral reflex responses in the cardiovascular organ, gastrointestinal tract, urinary bladder and adrenal medulla in anesthetized animals after eliminating emotional factors following somatic sensory stimulations. Various somatic sensory stimulations, including cutaneous, muscle and articular sensory stimulations, can produce differing autonomic reflex responses, depending on which visceral organs and somatic afferents are stimulated. Some responses have dominant sympathetic efferent involvement, whereas others have dominant parasympathetic efferent involvement. Some responses have propriospinal and segmental characteristics, while others have supraspinal and generalized characteristics in their reflex nature. These somatovisceral reflex responses may be functioning during spinal manipulative therapy in conscious humans.
Vertebral Malformations and Associated Somaticovisceral Abnormalities
Clin Radiol 1976 (Jul); 27 (3): 341–353
Numerous references to spine abnormalities and associated somatic and/or visceral abnormalities are reported. An implication is present in each that the association is more than just coincidental and some cause and effect relationship might exist. A series of cases was collected in which congenital spine abnormalities were noted on roentgenograms from patients evaluated for various reasons. Other roentgenograms of these patients and their medical records were reviewed in an attempt to find associated congenital abnormalities. Another group of patients with known congenital visceral malformations had their roentgenograms reviewed to see if the had spinal variations. It was found that patients with congenital vertebral malformations had an extremely high rate of associated visceral abnormalities, especially of the heart and kidneys. Other relationships between the spine and viscera include congenital lesions of the gastrointestinal and respiratory system and other parts of the renal system. This study also suggests the possible relationship between vesicoureteral reflux and spina bifida occulta.