White dog shaker syndrome (also known as idiopathic steroid responsive shaker syndrome, shaker dog syndrome and "little white shakers" syndrome; Latin name Idiopathic Cerebellitis) causes full body tremors in small dog breeds. It is most common in West Highland White Terriers, Maltese, Bichons, and Poodles, and other small dogs. There is a sudden onset of the disease at one to two years of age. It is more likely to occur, and the symptom is worse during times of stress. Nystagmus, difficulty walking, and seizures may occur in some dogs.

The cause is unknown, but it may be mediated by the immune system. One theory is that there is an autoimmune-induced generalized deficiency of neurotransmitters. Cerebrospinal fluid analysis may reveal an increased number of lymphocytes. Treatment with corticosteroids may put the dog into remission, or diazepam may control the symptoms. Typically the two drugs are used together. There is a good prognosis, and symptoms usually resolve with treatment within a week, although lifelong treatment may be necessary.

MRI: medial temporal lobe signal change bilateral hippocampal lesions, with signals that were hypointense in IR sequences and hyperintense in FLAIR.

Variable following immunotherapy with partial to excellent recovery.

Chronic sequelae due to hippocampal sclerosis and chronic epilepsy is also reported.

Neuromuscular junction disease is a medical condition where the normal conduction through the neuromuscular junction fails to function correctly.

Sulfonamide hypersensitivity syndrome is similar to anticonvulsant hypersensitivity syndrome, but the onset is often sooner in the treatment course, generally after 7–14 days of therapy.

It is considered immune-mediated.

Anticonvulsant/sulfonamide hypersensitivity syndrome is a potentially serious hypersensitivity reaction that can be seen with drugs with an aromatic amine chemical structure, such as aromatic anticonvulsants (e.g. diphenylhydantoin, phenobarbital, phenytoin, carbamazepine, lamotrigine), sulfonamides, or other drugs with an aromatic amine (procainamide). Cross-reactivity should not occur between drugs with an aromatic amine and drugs without an aromatic amine (e.g., sulfonylureas, thiazide diuretics, furosemide, and acetazolamide); therefore, these drugs can be safely used in the future.

The hypersensitivity syndrome is characterized by a skin eruption that is initially morbilliform. The rash may also be a severe Stevens-Johnson syndrome or toxic epidermal necrolysis. Systemic manifestations occur at the time of skin manifestations and include eosinophilia, hepatitis, and interstitial nephritis. However, a subgroup of patients may become hypothyroid as part of an autoimmune thyroiditis up to 2 months after the initiation of symptoms.

This kind of adverse drug reaction is caused by the accumulation of toxic metabolites; it is not the result of an IgE-mediated reaction. The risk of first-degree relatives’ developing the same hypersensitivity reaction is higher than in the general population.

As this syndrome can present secondary to multiple anticonvulsants, the general term "anticonvulsant hypersensitivity syndrome" is favored over the original descriptive term "dilantin hypersensitivity syndrome."

The signs and symptoms of a pheochromocytoma are those of sympathetic nervous system hyperactivity, including:

- Skin sensations

- Flank pain

- Elevated heart rate

- Elevated blood pressure, including paroxysmal (sporadic, episodic) high blood pressure, which sometimes can be more difficult to detect; another clue to the presence of pheochromocytoma is orthostatic hypotension (a fall in systolic blood pressure greater than 20 mmHg or a fall in diastolic blood pressure greater than 10 mmHg upon standing)

- Palpitations

- Anxiety often resembling that of a panic attack

- Diaphoresis (excessive sweating)

- Headaches – most common symptom

- Pallor

- Weight loss

- Localized amyloid deposits found microscopically

- Elevated blood glucose level (due primarily to catecholamine stimulation of lipolysis (breakdown of stored fat) leading to high levels of free fatty acids and the subsequent inhibition of glucose uptake by muscle cells. Further, stimulation of beta-adrenergic receptors leads to glycogenolysis and gluconeogenesis and thus elevation of blood glucose levels).

A pheochromocytoma can also cause resistant arterial hypertension. A pheochromocytoma can be fatal if it causes a hypertensive emergency, that is, severely high blood pressure that impairs one or more organ systems (formerly called "malignant hypertension"). This hypertension is not well controlled with standard blood pressure medications.

Not all patients experience all of the signs and symptoms listed. The most common presentation is headache, excessive sweating, and increased heart rate, with the attack subsiding in less than one hour.

Tumors may grow large, but most are smaller than .

In diseases such as myasthenia gravis, the end plate potential (EPP) fails to effectively activate the muscle fiber due to an autoimmune reaction against acetylcholine receptors, resulting in muscle weakness and fatigue.

Myasthenia gravis is caused most commonly by auto-antibodies against the acetylcholine receptor. It has recently been realized that a second category of gravis is due to auto-antibodies against MuSK. A different condition, Lambert-Eaton myasthenic syndrome, is usually associated with "presynaptic" antibodies to the voltage-dependent calcium channel. It is possible for these conditions to coexist.

The gold standard for measuring endothelial function is angiography with acetylcholine injection. Previously, this was not done outside of research because of the invasive and complex nature of the procedure. As mentioned above, the use of acetylcholine injections to test vasodilation is now safely used for procedures where arterial catheterization is employed (this method is less frequently used though, so overall acetylcholine is not used very often in this way).

A noninvasive method to measure endothelial dysfunction is % Flow Mediated Dilation (FMD) as measured by Brachial Artery Ultrasound Imaging (BAUI). Current measurements of endothelial function via FMD vary due to technical and physiological factors. For example, FMD is largely affected by hormones, especially for women. FMD values can differ for the same woman if she is in different phases of her menstrual cycle during the time of measurement. When using this technique on people who suffer from things like heart failure, renal failure, or hypertension, their increased sympathetic tone can often falsify the results. Furthermore, a negative correlation between percent flow mediated dilation and baseline artery size is recognised as a fundamental scaling problem, leading to biased estimates of endothelial function. For research on FMD an ANCOVA approach to adjusting FMD for variation in baseline diameter is more appropriate. Another challenge of FMD is variability across centers and the requirement of highly qualified technicians to perform the procedure.

A non-invasive, FDA-approved device for measuring endothelial function that works by measuring Reactive Hyperemia Index (RHI) is Itamar Medical's EndoPAT™. It has shown an 80% sensitivity and 86% specificity to diagnose coronary artery disease when compared against the gold standard, acetylcholine angiogram. This results suggests that this peripheral test reflects the physiology of the coronary endothelium. Endopat has been tested in several clinical trials at multiple centers (including major cohort studies such as the Framingham Heart Study, the Heart SCORE study, and the Gutenberg Health Study). The results from clinical trials have shown that EndoPAT™ is useful for risk evaluation, stratification and prognosis of getting major cardiovascular events (MACE).

Since NO maintains low tone and high compliance of the small arteries at rest a reduction of age-dependent small artery compliance is a marker for endothelial dysfunction that is associated with both functional and structural changes in the microcirculation that are predictive of subsequent morbid events Small artery compliance or stiffness can be assessed simply and at rest and can be distinguished from large artery stiffness by use of pulsewave analysis with the CV Profilor.

ZAP70 deficiency, or zeta-chain-associated protein 70 kD deficiency, is a rare autosomal recessive form of severe combined immunodeficiency (SCID).

It is associated with ZAP70.

Pemphigus herpetiformis (also known as "Acantholytic herpetiform dermatitis," "Herpetiform pemphigus," "Mixed bullous disease," and "Pemphigus controlled by sulfapyridine") is a cutaneous condition, a clinical variant of pemphigus that combines the clinical features of dermatitis herpetiformis with the immunopathologic features of pemphigus.

Pathophysiology:

Pemphigus Herpetiformis is an IGg mediated autoantibodies that affect the epidermal layer of the skin.

PPH presents roughly equally in male and female cirrhotics; 71% female in an American series and 57% male in a larger French series. Typically, patients present in their fifth decade, aged 49 +/- 11 years on average.

In general, PPH is diagnosed 4–7 years after the patient is diagnosed with portal hypertension and in roughly 65% of cases, the diagnosis is actually made at the time of invasive hemodynamic monitoring following anesthesia induction prior to liver transplantation.

Once patients are symptomatic, they present with right heart dysfunction secondary to pulmonary hypertension and its consequent dyspnea, fatigue, chest pain and syncope. Patients tend to have a poor cardiac status, with 60% having stage III-IV NYHA heart failure.

PPH is actually independent of the severity of cirrhosis but may be more common in specific types of cirrhosis, in one series more so in Autoimmune Hepatitis and less in Hepatitis C cirrhosis, while in another it was equally distributed throughout the diagnoses.

The skin is normal at birth. Between 3 and 6 months of age, the affected carrier develops poikiloderma on the cheeks. This characteristic "rash" that all RTS carriers have can develop on the arms, legs and buttocks. "Poikiloderma consists of areas of increased and decreased pigmentation, prominent blood vessels, and thinning of the skin."

It is characterized by a lack of CD8+ T cells and the presence of circulating CD4+ T cells which are unresponsive to T-cell receptor (TCR)-mediated stimuli.

The epidemiology of endothelial dysfunction is unknown, as %FMD varies with baseline artery diameter. This can make cross-sectional comparisons of %FMD difficult. Endothelial dysfunction was found in approximately half of women with chest pain, in the absence of overt blockages in large coronary arteries. This endothelial dysfunction cannot be predicted by typical risk factors for atherosclerosis (e.g., obesity, cholesterol, smoking) and hormones.

All people with ALPS have signs of lymphoproliferation, which makes it the most common clinical manifestation of the disease. The increased proliferation of lymphoid cells can cause the size of lymphoid organs such as the lymph nodes and spleen to increase (lymphadenopathy and splenomegaly, present in respectively over 90% and over 80% of patients). The liver is enlarged (hepatomegaly in 30 - 40% of patients).

Autoimmune disease is the second most common clinical manifestation and one that most often requires treatment. Autoimmune cytopenias: Most common. Can be mild to very severe. Can be intermittent or chronic. These include: Autoimmune hemolytic anemia, Autoimmune neutropenia, Autoimmune thrombocytopenia.

Other signs can affect organ systems similar to systemic lupus erythematosus (least common, affecting <5% of patients) Symptoms of the nervous system include: Autoimmune cerebellar ataxia; Guillain–Barré syndrome; transverse myelitis. Gastrointestinal signs like Autoimmune esophagitis, gastritis, colitis, hepatitis, pancreatitis can be found or (Dermatologic) Urticaria, (Pulmonary) bronchiolitis obliterans, (Renal) Autoimmune glomerulonephritis, nephrotic syndrome.

Another sign are cancers such as Hodgkin and non-Hodgkin lymphomas which appear to be increased, possibly due to Epstein–Barr virus-encoded RNA-positivity. Some carcinomas may occur. Unaffected family members with genetic mutations are also at an increased risk of developing cancer.

Portopulmonary hypertension (PPH) is defined by the coexistence of portal and pulmonary hypertension. PPH is a serious complication of liver disease, present in 0.25 to 4% of all patients suffering from cirrhosis. Once an absolute contraindication to liver transplantation, it is no longer, thanks to rapid advances in the treatment of this condition. Today, PPH is comorbid in 4-6% of those referred for a liver transplant.

Brugada syndrome (BrS) is a genetic condition that results in abnormal electrical activity within the heart, increasing the risk of sudden cardiac death. Those affected may have episodes of passing out. Typically this occurs when a person is at rest.

It is often inherited from a person's parent with about a quarter of people having a family history. Some cases may be due to a new mutation or certain medications. The abnormal heart rhythms can be triggered by a fever or increased vagal tone. Diagnosis is typically by electrocardiogram (ECG), however, the abnormalities may not be consistently present.

Treatment may be with an implantable cardioverter defibrillator (ICD). Isoproterenol may be used in those who are acutely unstable. In those without symptoms the risk of death is much lower, and how to treat this group is unclear. Testing people's family members may be recommended.

Between 1 and 30 per 10,000 people are affected. Onset of symptoms is usually in adulthood. It is more common in people of Asian descent. Males are more commonly affected than females. It is named after the Spanish cardiologists Pedro and Josep Brugada who described the condition in 1992. Their brother Ramon Brugada described the underlying genetics in 1998.

Pheochromocytoma (PCC) is a neuroendocrine tumor of the medulla of the adrenal glands (originating in the chromaffin cells), or extra-adrenal chromaffin tissue that failed to involute after birth, that secretes high amounts of catecholamines, mostly norepinephrine, plus epinephrine to a lesser extent. Extra-adrenal paragangliomas (often described as extra-adrenal pheochromocytomas) are closely related, though less common, tumors that originate in the ganglia of the sympathetic nervous system and are named based upon the primary anatomical site of origin. The term is from Greek "phaios" "dark", "chroma" "color", "kytos" "cell", "-oma" "tumor".

Rothmund–Thomson syndrome (RTS), also known as poikiloderma atrophicans with cataract or poikiloderma congenitale, is a rare autosomal recessive skin condition originally described by August von Rothmund (1830–1906) in 1868. Matthew Sydney Thomson (1894–1969) published further descriptions in 1936.

There have been several reported cases associated with osteosarcoma. A hereditary genetic basis, mutations in the DNA Helicase "RECQL4" gene, causing problems during initiation of DNA replication has been implicated in the syndrome

The primary symptoms of a cytokine storm are high fever, swelling, redness, extreme fatigue, and nausea. In some cases the immune reaction will be fatal.

Signs/symptoms of humoral immune deficiency depend on the cause, but generally include signs of infection such as:

- Sinusitis

- Sepsis

- Skin infection

- Pneumonia

A cytokine storm, also known as cytokine cascade and hypercytokinemia, is a potentially fatal immune reaction consisting of a positive feedback loop between cytokines and white blood cells, with highly elevated levels of various cytokines. The term arose in the field of pathophysiology in discussions around immune disorders in 1993, was extended to discussions of infectious disease and sepsis, and has been used to describe severe manifestations of cytokine release syndrome, an adverse effect of some drugs.

Functional gastrointestinal disorders are very common. Globally, irritable bowel syndrome and functional dyspepsia alone may affect 16–26% of the population.

Genetic testing for Brugada syndrome is clinically available and may help confirm a diagnosis, as well as differentiate between relatives who are at risk for the disease and those who are not. Some symptoms when pinpointing this disease include fainting, irregular heartbeats, and chaotic heartbeats. However, just detecting the irregular heartbeat may be a sign of another disease, so the doctor must detect another symptom as well.