Conn's Syndrome

A hypertensive disorder resulting from excess production of aldosterone by the adrenal gland.

Causes and Incidence 
Most cases are caused by an adenoma of the adrenal gland. Other causes are adrenal nodular hyperplasia and adrenal carcinoma. Only 0.5% to 2% of those with hypertension are affected. The condition is three times more likely to affect women; the typical age ranges from 30 to 50 years.

Disease Process 
Excess production of aldosterone leads to hypernatremia, hypervolemia, and hypokalemic alkalosis. Mild to severe arterial hypertension occurs because of the increased volume and arteriolar sodium levels. Hypokalemia results from increased renal excretion of potassium, and metabolic alkalosis occurs because of an increase in hydrogen ion secretion. Over time this leads to transient paralysis and tetany.

Symptoms 
In many cases the only manifestation is a mild to moderate hypertension. Other signs and symptoms include episodic weakness, fatigue, paresthesia, polyuria, polydipsia, and nocturia. Glycosuria, hyperglycemia, and personality disturbances are occasionally manifested.

Potential Complications 
Marked alkalosis with transient paralysis, tetany, and positive Chvostek's and Trousseau's signs.
 

Diagnostic Tests 

Plasma renin activity 
Decreased (measured after restricted sodium/diuretic therapy)

Aldosterone levels
Increased (measured after  sodium loading)

Blood chemistry
Normal/increased sodium, decreased potassium

Computed tomography scan
To detect presence of adenoma

Blood pressure
Elevated

Edema
Absent
 

Treatments 

Surgery
Adrenalectomy

Drugs
Spironolactone (Aldactone)

General 
Low-sodium diet; instruction about medication, diet, and surgery.

Adult Respiratory Distress Syndrome (ARDS)

Acute respiratory failure associated with pulmonary injury and characterized by noncardiogenic pulmonary edema, hypoxemia, and severe respiratory distress.

Causes and Incidence 
Adult respiratory distress syndrome (ARDS) is precipitated by a variety of acute processes that injure the lung. Trauma is the most common cause; others are anaphylaxis, aspiration of gastric reflux, pneumonia, inhalation burns from fire or chemicals, drug reactions, drug overdose, near-drowning, and oxygen toxicity. The condition may also develop as the result of an underlying disease process (e.g., leukemia, tuberculosis, pancreatitis, uremia, thrombocytopenic purpura) or as a byproduct of a medical procedure (e.g., coronary artery bypass, multiple blood transfusions, mechanical ventilation, hemodialysis). 

The incidence and mortality are elusive, because ARDS is often misdiagnosed. Other names for ARDS include such names as shock lung, wet lung, stiff lung, white lung, Da Nang lung, or adult hyaline membrane disease. Recent studies place the survival rate at about 50% with treatment.

Disease Process 
The initial injury to the lung is poorly understood. It is hypothesized that activated WBCs and platelets accumulate in the capillaries, interstitium, and air spaces and release prostaglandins, oxygen radicals, proteolytic enzymes, and other products. These injure the cells, increase fibrosis, and reduce bronchomotor tone, leading to capillary leakage of blood and plasma into the interstitial and alveolar spaces. This results in alveolar flooding and reduced surfactant activity, producing atelectasis. Bronchial inflammation and proliferation of epithelial and interstitial cells follow. Collagen accumulates, resulting in severe interstitial fibrosis (stiff lung) with low lung compliance, reduced functional residual capacity (FRC), pulmonary hypertension, perfusion maldistribution, and hypoxemia.
 

Symptoms  

Early   
Dyspnea, particularly on exertion, followed by rapid, shallow respirations, inspirational chest retractions, and wheezing

Late   
Bloody, sticky sputum; racing heart rate; clammy, mottled, cyanotic skin; severe difficulty breathing; confusion; coma

Potential Complications 
Complications include secondary bacterial superinfections, tension pneumothorax, multiple-system organ failure, metabolic and respiratory acidosis, and cardiac arrest.
 

Diagnostic Tests
 

Pulmonary function  
Decreased FRC and compliance;  low/normal pulmonary capillary web pressure; increased shunt fraction

Arterial blood gases
Decreased PaO2; low/normal PaCO2; elevated pH

Lactic acid
Elevated

Radiology 
Blurred margins and alveolar infiltrates on early chest x-rays; normal cardiac silhouette
 

Treatments 
Mechanical ventilation with positive end-expiratory pressure and continuous positive airway pressure is generally required until the underlying problem has been identified and treated. 

Surgery
None

Drugs     
No specific drugs; morphine and pancuronium bromide (Pavulon) are used in the management of mechanical ventilation; antiinfective drugs may be used for underlying infections

General                 
Correction of underlying cause of injury; hyperalimentation to prevent nutritional depletion; blood gas monitoring to prevent oxygen toxicity; careful aseptic technique and monitoring of secretions to prevent superinfection; intubation and ventilation; tracheobronchial suctioning to clear secretions; cardiac monitoring; bed rest; fluid volume replacement; regulation of activity to reduce hypoxia; instruction in communicating with intubated patient; communication tools (e.g., alphabet or picture boards, response switches).

Addison's Disease

Addison's disease is a progressive, chronic disease process resulting from a decline in the production of adrenocortical steroids as the adrenal cortex is destroyed.

Causes and Incidence 
Most cases are the result of idiopathic atrophy of the adrenal cortex; the rest are due to destruction of the entire gland. Clinical signs often are manifested during periods of metabolic stress. About 4 in 100,000 individuals, across all age groups, are affected.

Disease Process 
A decline in cortisol and corticosterone production by the adrenal cortex results in multiple disturbances in fat, protein, and carbohydrate metabolism, which in turn give rise to diminished production of liver glycogen and increased production of insulin. This leads to hypoglycemia and muscle weakness. Electrolyte imbalances and dehydration are caused by an increase in sodium (Na) secretion and a decrease in potassium (K) secretion, leading to low serum concentrations of sodium and chloride and high serum concentrations of potassium. The decrease in cortisol also leads to an increase in adrenocorticotropic hormone (ACTH) and beta-lipotropin, which stimulates melanin production and causes hyperpigmentation. Over time, resistance to infection and stress diminishes. Dehydration may lead to reduced cardiac output and, ultimately, circulatory collapse.
 

Symptoms 

Early
Weakness, fatigue, orthostatic 

hypotension, tanning, freckles, vitiligo, darkened mucosal areas

Midcourse  
Nausea, vomiting, diarrhea, abdominal pain, headaches, dizziness, fainting, intolerance to cold

Late  
Weight loss, dehydration, hypotension, confusion, restlessness, emotional lability, small heart size
 

Potential Complications 
Acute stress or trauma in which the body's store of glucocorticoids is exhausted may trigger an adrenal crisis, which is characterized by generalized muscular debility; severe abdominal, back, and leg cramps; peripheral vascular collapse; and acute renal failure.
 

Diagnostic Tests 

ACTH stimulation test
No increase in cortisol

Blood chemistry  
Elevated potassium and blood  urea nitrogen (BUN); decreased sodium, bicarbonate, and fasting glucose

Complete blood count 
Na:K ratio less than 30:1; elevated hematocrit, eosinophils, and lymphocytes; decreased WBCs

Radiology 
Small heart; small adrenal size, calcifications; renal or pulmonary tuberculosis
 

Treatments 


Surgery
None

Drugs       
IV hydrocortisone, sodium chloride replacement; vasopressors to elevate blood pressure; hydrocortisone/fludrocortisone PO maintenance for life; antibiotics with evidence of infection; antitubercular drugs with evidence of tuberculosis

General      
Fluid replacement IV and PO; high-calorie diet; cardiac monitoring for peaked T waves; rest; monitoring for signs of infection; monitoring of urine output; instruction about the disease and maintenance medications.

Acquired Immune Deficiency Syndrome (AIDS)

Acquired Immune Deficiency Syndrome or better known as AIDS, is a terminal, secondary immunodeficiency syndrome characterized by dysfunction of cell-mediated immunity and manifested by opportunistic infections and malignancies.

Causes and Incidence
The cause is thought to be one of several related retroviruses (human immunodeficiency virus, or HIV) that convert viral RNA into a proviral DNA copy, which is incorporated into the DNA of the host cell. The proviral copy then is duplicated with normal cellular genes during each cellular division. HIV is a blood-borne virus and commonly is transmitted through exchange of body fluids during sexual contact, through parenteral exposure or fetal exposure to blood, and through select body fluids from an individual infected with HIV. Infants are at risk of acquiring the HIV during fetal development, delivery, or breast-feeding from an HIV-positive mother.
High-risk behavior for HIV exposure includes unprotected sexual activity and IV drug use with shared needles. Occupational transmission to health care workers is possible through needle sticks or other exposure to HIV-infected blood. Individuals infected with HIV who are asymptomatic are in a carrier state and may transmit the disease without displaying any of the characteristic signs of AIDS.
 
AIDS is a global pandemic, and it is predicted that more than 110 million people worldwide will be infected with HIV by the end of the century. As of 1991 more than 1.1 million people worldwide had died.
 
In the United States the incidence of AIDS has steadily increased from 3.46 per 100,000 population in 1985 to 40.20 per 100,000 population in 1993. Although it is far too early to interpret the reasons, in 1994 the incidence of reported AIDS cases dropped slightly, to 30.07 per 100,000 population. All races and ethnic groups are affected. Currently men far outnumber women as victims of the disease. However, the fastest rise in cases is occurring among minority women. The median age range for all individuals with AIDS is 30 to 39 years.

Disease Process
The current theory holds that as HIV is reproduced, it affects the immune system by infecting the T-helper cell lymphocytes, which usually coexist in a 2:1 ratio with T-suppressor cells. As the viruses replicate, masquerading as helper cells, the number of real helper cells declines, and the T-suppressor cells eventually dominate, leading to immunosuppression and a lowering of the body's prime defense mechanism against intracellular pathogens and the formation of malignant tumors.

Symptoms
AIDS is a chronic, progressive, terminal illness that can be divided into four stages, as defined by the federal Centers for Disease Control and Prevention (CDC): 

Stage I  
An acute, flulike syndrome that develops at the time of initial infection and lasts from days to weeks

Stage II 
An asymptomatic, HIV-positive carrier state that may persist for years

Stage III
Generalized, persistent lymphadenopathy

Stage IV                 
The development of other disease processes, including (1) constitutional disease (weight loss greater than 10% of body weight, persistent diarrhea, fever, malaise, oral thrush); (2) neurologic disease (peripheral neuropathies, paresthesia, myelopathy, dementia); (3) opportunistic infections (bacterial, viral, fungal, or protozoal) and their accompanying clinical features; (4) secondary neoplasms; and (5) other conditions (e.g., endocarditis, interstitial pneumonitis, immune thrombocytopenic purpura)

Potential Complications
The complications are numerous and are associated with the various opportunistic infections or neoplasms, as well as the repetitive nature of the infections. These infections eventually overwhelm the body's compromised immune system, leading to massive infectious invasions in every body system and, eventually, death.

Diagnostic Tests 

Clinical evaluation 
Any of the above manifestations; history of high-risk behavior

Enzyme-linked immunosorbent assay (ELISA)
Screening test for HIV antibody  (may be positive from 0 to 12 months after exposure)

Western blot/ immunofluorescent assay
To confirm reactive seropositive  results obtained by ELISA test 

WBCs/lymphocytes
Depressed

T-cell studies  
Reduced reactivity and function  of T cells; reduced number of T-helper cells, increased number of T-suppressor cells

B-cell studies
Numbers and function normal or  increased

Natural killer (NK) cells
Reduced activity

Complement
Normal or increased

Treatments 

Surgery
Tumor excision of some related neoplasms

Drugs                     
Experimental treatment with various retroviral drugs such as zidovudine (Retrovir; formerly azidothymidine [AZT]); didanosine (Videx; formerly dideoxyinosine [ddI]; and zalcitabine (Hivid; formerly dideoxycytidine [ddC]), using CD4 lymphocyte counts as a treatment guide; prophylaxis with trimethoprim-sulfamethoxazole tablets to prevent Pneumocystis carinii pneumonia (PCP); rifabutin prophylaxis for Mycobacterium avium infection; drugs specific for various opportunistic infections; chemotherapy for carcinomas; prophylactic use of zidovudine following exposure through penetrating injuries is controversial

General               
Measures to improve overall health (e.g., no smoking, balanced nutrition, drug rehabilitation, flu vaccine, pneumococcal vaccine, hepatitis B vaccine); supportive measures for coping with and adapting to the effects of the disease (e.g., counseling, support groups); instruction in how the disease is spread in order to promote prevention, particularly among high-risk groups; use of universal precautions by health care workers and family members to prevent transmission.

Abruptio Placentae

A premature separation of a normally implanted placenta from the uterine wall, usually occurring in the third trimester of pregnancy.

Causes and Incidence The etiology is unknown but is believed to be related to hypertensive and cardiovascular disease processes or use of cocaine. Abruptio placentae occurs in 0.5% to 3.5% of all deliveries.

Disease Process The placenta releases from the wall of the uterus, and retroplacental bleeding occurs. The degree of release may vary from a few millimeters to complete detachment. Blood can accumulate under the placenta (concealed hemorrhage) or can be passed behind the membranes and out the cervix (external hemorrhage).

Symptoms The signs and symptoms vary with the degree of separation and the resultant amount of hemorrhage. Severe cases involve slight to profuse vaginal bleeding; maternal shock (hypotension, dizziness, rapid pulse, dyspnea, pallor); sudden, severe pain; tender, tightly contracted uterus; and fetal distress or fetal death.

Potential Complications Hypofibrinogenemia with disseminated intravascular coagulation (DIC), uteroplacental apoplexy (Couvelaire uterus), and renal failure are possible, particularly if the woman has preexisting toxemia.
 

Diagnostic Tests 

Abdominal ultrasound

To rule out placenta previa
 

Treatments 
 
Surgery 
Cesarean section (unless vaginal delivery is imminent) when bleeding cannot be controlled
 
Drugs
None
 
General      
Bed rest until bleeding stops; fluid and volume replacement by intravenous administration; blood replacement if necessary to prevent shock; rupture of membranes if delivery is imminent to reduce the possibility of DIC