H—Hereditary lesions include eczema and psoriasis.

A—Autoimmune disorders include lupus.

I—Inflammatory diseases include ringworm, impetigo, and seborrheic dermatitis. I also stands for idiopathic and thus includes pityriasis simplex capitis.

R—Radiation dermatitis.

V—Vascular includes cerebral thrombosis, embolism, and especially hemorrhage of the brainstem, which may cause depressed respirations or periodic apnea. Diffuse cerebral arteriosclerosis is another cause in this category.

I—Inflammatory disorders signify encephalitis, poliomyelitis, meningitis, and brain abscesses, particularly with increased intracranial pressure.

N—Neoplasms of the brainstem (primary or metastatic) and neoplasms of the cerebrum are associated with increased intracranial pressure and may cause depression of respirations and Cheyne–Stokes breathing.

D—Degenerative diseases of the brain, including senile and presenile dementia and Schilder disease, may cause these signs in the terminal stages.

I—Intoxication is an important category of etiologies of depressed or irregular respirations because the toxic substance may not be obvious at first. Failure of any organ system to function may lead to respiratory depression. When there is respiratory failure from emphysema or other causes, carbon dioxide (CO₂) builds up in the blood and CO₂ narcosis develops. In this state the important stimulus of high blood CO₂ on the respiratory centers is gradually lost and anoxia is the only stimulus left. Periodic or Cheyne–Stokes breathing frequently develops in the following manner: During respiration the blood oxygen builds up to a level at which the respiratory stimulus to anoxia is lost. Respirations cease. During apnea the blood oxygen falls to a point where there is sufficient anoxia to kick the respiratory center over again. The electrolyte disturbances and buildup of toxins in uremia, the high blood ammonia and other toxins that result from hepatic failure, and the anoxia of congestive heart failure (CHF) may all lead to apnea or depressed respirations.

C—Congenital disorders that cause these respiratory disturbances include Tay–Sachs disease, cerebral palsy, glycogen storage disease, reticuloendothelioses, epilepsy, and cerebral aneurysms with subarachnoid hemorrhage.

A—Autoimmune disorders such as lupus erythematosus and multiple sclerosis (MS) must be considered in this category.

T—Trauma is another frequent cause of apnea or Cheyne–Stokes respiration. Cerebral concussion, subdural, epidural, and intracerebral hematomas all may cause depressed respirations, especially when associated with increased intracranial pressure.

E—Endocrine disease reminds the reader that whereas diabetic coma may begin with Kussmaul breathing, in the advanced stages bradypnea and Cheyne–Stokes respirations develop from the severe acidosis. Pituitary and suprasellar tumors may grow sufficiently to compress the brainstem and cause apnea.

Hypothalamus and pituitary: Lack of gonadotropin-releasing hormone from hypothalamic disorders such
as Laurence–Moon–Biedl syndrome, space-occupying lesions, trauma, or infection may cause delayed puberty in girls and boys. Chromophobe adenomas, prolactinomas, craniopharyngiomas, trauma, granulomas, and vascular lesions may decrease the production of growth hormone and other pituitary hormones causing delayed puberty.

Thyroid: Both hypothyroidism and hyperthyroidism in children may cause delayed puberty.

Adrenal gland: Visualizing this organ will prompt the recall of congenital adrenocortical hyperplasia and Cushing syndrome.

Ovaries: Ovarian dysgenesis (Turner syndrome etc.), autoimmune oophoritis, and Noonan syndrome are associated
with delayed puberty in girls. A masculinizing tumor of the ovary will present with delayed puberty on occasion.

Testicles: Irradiation, Klinefelter syndrome, Noonan syndrome, castration, and anorchism may cause delayed puberty in boys. Mumps rarely is the cause.

V—Vascular disorders of the brain including hemorrhage, embolism, thrombosis, and arteriosclerosis may cause delirium.

I—Inflammatory disorders of the nervous system that may cause delirium include viral encephalitis, meningitis, syphilis, malaria and other parasites, rabies, and cerebral abscess. Generalized infections, usually when associated with fever, may be responsible.

N—Neoplasms of the brain are not usually associated with delirium until the end stages at which time the cause will be obvious.

D—Deficiency disorders that may be associated with delirium include Wernicke encephalopathy, pellagra, and pernicious anemia. Delirium may be associated with degenerative disorders such as Alzheimer disease.

I—Intoxication by an enormous number of exogenous and endogenous substances may cause delirium. Alcohol, cocaine, heroin, phencyclidine (PCP), marijuana, lead, arsenic, and manganese are just a few of the exogenous substances. Endogenous substances include uremia, ammonia from hepatic failure, hyperinsulinemia, diabetic ketosis, and porphyria. Delirium may be associated with the withdrawal of a patient from alcohol and/or any drug including morphine, cocaine, or tobacco.

C—Convulsive disorders may be associated with delirium either during or after the seizure.

A—Autoimmune disorders such as lupus erythematosus are associated with inflammation of vasculitis in the brain causing delirium.

T—Trauma may cause a concussion, cerebral hemorrhage, or subdural or epidural hematoma leading to delirium.

E—Endocrine disorders associated with delirium include insulinoma and diabetes.

V—Vascular disorders suggest cerebral arteriosclerosis with lacunar infarcts or cerebral emboli.

I—Inflammatory disorders suggest cerebral abscess, tuberculomas, viral encephalitis (e.g., herpes simplex), and general paresis.

N—Neoplasms, both primary and metastatic, should always be considered, as these are potentially treatable.

D—Degenerative diseases include senile and presenile dementia, Huntington chorea, diffuse sclerosis, and many other conditions.

I—Intoxication brings to mind alcoholism, bromism, chronic use of both “uppers” and “downers,” lysergic acid diethylamide (LSD), and cannabis. Uremia, CO₂ narcosis, chronic anoxia, electrolyte disorders, and early hepatic coma should also be considered.

C—Congenital diseases suggest Schilder disease, mongolism, Wilson disease, and many other conditions associated with mental retardation.

A—Autoimmune diseases focus on lupus erythematosus, allergic angiitis, and MS.

T—Trauma facilitates the recall of concussion and chronic subdural hematomas.

E—Endocrine disorders include suprasellar tumors that invade the hypothalamus, acromegaly, hypopituitarism, hyperthyroidism, Cushing syndrome, and adrenal insufficiency. Parathyroid dysfunction can also cause delusions.

V—Vascular diseases include myocardial infarction, CHF, cerebral arteriosclerosis, and thrombosis.

I—Inflammatory diseases recall syphilis, encephalitis, tuberculosis, brain abscess, influenza, pneumonia, and any prolonged infectious state, particularly that of the hospitalized patient with tubes in every orifice.

N—Neoplasms include cerebral tumors, tumors of the endocrine glands, and any neoplasm which is metastatic or which affects the metabolism of the body by a hormone or enzyme which it secretes. Pancreatic carcinoma is frequently associated with depression.

D—Degenerative diseases and deficiency diseases suggest presenile and senile dementia, pellagra, Wilson disease, and atrophy of the various endocrine glands.

I—Intoxication suggests lead poisoning, alcoholism, bromism, hypercalcemia, hypocalcemia, manganese toxicity, hypokalemia, hypovolemia, uremia, anoxia from pulmonary disease, anemia, heart disease, and corticosteroid therapy, as well as many other drugs. Porphyria may cause depression or a psychotic state.

C—Congenital suggests the depression associated with many congenital neurologic diseases: epilepsy, muscular dystrophy, Friedreich ataxia, myotonic dystrophy, and the depression associated with congenital heart disease and congenital defects of many organ systems.

A—Autoimmune diseases include MS and lupus erythematosus.

T—Traumatic disorders include the now well-recognized posttraumatic neurosis or depression, neurocirculatory asthenia, and postconcussion syndrome. Compensation neurosis should be mentioned here. Sexual abuse is a common cause in children.

E—Endocrine diseases include hypopituitarism, acromegaly, hypothyroidism, apathetic hyperthyroidism,

hypoparathyroidism, hyperparathyroidism, diabetes mellitus, insulinoma, hypogonadism, menopause, Cushing syndrome, and adrenal insufficiency.

V—Vascular diseases include ischemic colitis.

I—Infectious agents such as bacillary dysentery (Shigella), Escherichia coli, Campylobacter, Yersinia, and amebiasis may ulcerate or inflame the colon.

N—Neoplasms such as carcinomas and polyps cause chronic irritation and exudates from the colon with hypermotility and diarrhea.

D—Degenerative lesions of the muscularis that cause diverticulosis and allow overgrowth of bacteria and chronic
inflammation may lead to diarrhea, but this may be classified under the idiopathic category as well.

I—Intoxicating substances, osmotic cathartics, and antibiotics (by allowing overgrowth of bacteria and fungi) may involve the colon (e.g., pseudomembranous colitis). Mucous colitis or irritable bowel syndrome may best be classified as idiopathic. Laxative abuse is a frequent cause of chronic diarrhea.

C—Congenital lesions of the colon include the solitary diverticulum of the cecum, malrotation (more frequently associated with intestinal obstruction), and familial polyposis.

A—Autoimmune disease of the colon is common and includes both ulcerative colitis and granulomatous colitis.

T—Trauma is not a common cause of diarrhea anywhere in the intestinal tract, but certainly surgically induced fistulas may occur in the colon or anywhere else.

E—Endocrine disorders do not usually affect the colon directly.