Orthostatic hypotension

Disease class: Hypotension

Hypertension

Disease class: Vascular diseases

Types

• Essential hypertension
• hypertension, Malignant
• hypertension, Pregnancy-induced
• hypertension, Renal
• Hypertensive retinopathy
• Masked hypertension
• White coat hypertension

 

Also known as

• Hypertensive diseases
  
• HTN (often written in medical records)
• High blood pressure

 

In brief

• Hypertension is a risk factor for many diseases, such as heart failure and renal failure.
• Hypertension is a risk factor for many sudden onset events, such as stroke.
• Minimising hypertension in the population significantly reduces the number of these diseases.

What is "high"?

European Heart Journal:34;2159–2219

• A commonly cited "normal" or "healthy" blood pressure for the average adult is 120/80. This means that the blood pressure is 120 mmHg during systole and 80 mmHg during diastole. The mean arterial pressure would be around 93 mmHg.
• Blood pressure varies with age. Children tend to have a lower blood pressure and old adults tend to have a higher blood pressure. 
• Frequent exercisers tend to have lower blood pressure values.
• In an acute situation, it is important to consider what is normal for the patient. Even a blood pressure of 120/80 could be high for them.

Symptoms and signs

• Hypertension is usually asymptomatic and detected by routine blood pressure measurement.
• Symptoms are more common with hypertensive crises or complications of chronic hypertension.
• Headache
• Light-headedness
• Visual disturbances

Risk factor for:

• Stroke
• Ischaemic heart disease
• Peripheral vascular disease
• Heart failure
• Dementia

 

Complications

• Hypertensive retinopathy
• Hypertensive nephropathy
• Hypertensive encephalopathy

 

Acute severe hypertension (urgency/crisis/emergency)

• When hypertension is severe enough it is known as a hypertensive urgency.
• The combination of hypertensive urgency, and signs of acute organ damage is a medical emergency. This is known as a hypertensive crisis, hypertensive emergency or malignant hypertension. Within minutes of a hypertensive crisis there is a significant risk of complications such as stroke.
• Rapid reduction in blood pressure can precipitate complications such as strokes.

Aetiology and pathophysiology

• If successful treatment of another disease causes the hypertension to completely resolve, then it is called secondary hypertension. The hypertension is "secondary" to that disease.
• There are many causes of secondary hypertension, particularly kidney dysfunction and endocrine disorders.
• Most cases of hypertension are essential hypertension (also called primary hypertension). This means that the body has failed to regulate the blood pressure within healthy limits, usually as a result of ageing. These patients may have no other medical conditions. Even if these patients have another medical condition, and it is completely reversed by treatment, the hypertension will not resolve.

Management

• Detect and confirm hypertension.
• Establish whether hypertension is primary or secondary. If secondary, what is the cause?
• Aim to control blood pressure values, minimising time out of target range.

Reducing blood pressure values to a target level should be done over the course of days. Rapid drops in blood pressure can precipitate strokes. 

• Lifestyle changes. Dietary changes. Reduction of salt intake.
• Medical therapy
• Vasodilator therapy

Hypotension

Disease class: Vascular diseases

Types

• hypotension, Orthostatic
• Post-exercise hypotension
• Shy-Drager syndrome

Venous insufficiency

Disease class: Vascular diseases

Signs

• Varicose veins

 

History of radiation injuries

This post chronicles significant incidents of radiation-induced injury.
It was inspired by the high quality new miniseries Chernobyl, produced by HBO.

 

Please refer to:

• Ionising radiation
• Radiation injuries

 

Timeline

• 1903: Marie and Pierre Curie won the Nobel Prize for their research into radiation. Pierre Curie died of a head injury in 1906. In 1934, Marie Curie died of radiation-induced aplastic anaemia.
• 1945: 18 USA citizens were injected with plutonium in a series of experiments without informed consent. They were selected because they had diagnosed terminal illnesses. Each died of their original illness.
• Albert Stevens was injected with 131 kBq plutonium.
• He was never diagnosed with any radiation injuries. He died of apparently unrelated heart failure 21 years later, in 1966, aged 79
• The total dose emitted was 64 Sv, by his time of death.
• The doctor who led the human plutonium experiments, Dr. Joseph Gilbert Hamilton, died of radiation-induced leukaemia in 1957, aged 49.
• 1945: After the atomic bombing of Hiroshima and Nagasaki by the USA, there were 129,000–226,000 estimated casualties.
• Within the first few months, 90,000-166,000 people died in Hiroshima, 60,000-80,000 died in Nagasaki. 
• Early deaths and injuries occured as a result of the explosion itself and ARS. 
• 1978: Russian scientist Anatoli Bugorski was shot in the head by a high energy proton beam. He received a dose of over 8 Sv and the high energy beam burnt a narrow hole through his head. He survived the incident and recovered with minor disabilities. He went on to complete his PhD and he is currently still alive at 77 years old.
• 1986: The disaster at the Chernobyl Nuclear Power Plant, in Pripyat, Ukraine. 
• There was an explosion which breached the core. The ongoing fission reaction maintained open fires for days, which propelled large quantities of highly radioactive materials (including the radioisotope iodine-131) into the atmosphere. The enviroment and local ecosystems were heavily contaminated by these materials.
• Radiation level estimates were over 20,160 roentgens per hour in some areas. This is equivalent to 0.056 Sieverts per second. After 18 seconds the absorbed dose would be over 1 Sv, high enough to cause ARS in a typical patient. After 90 seconds, the absorbed dose would be over 5 Sv, high enough to cause fatal ARS in a typical patient.
• Some servicemen worked in these contaminated areas for many hours.
• 237 of the most exposed individuals developed ARS, of whom 31 died within 3 months. A further 15 later developed fatal thyroid cancer.
• These patients were contaminated with strongly radioactive materials. Their bodies were emitting ionising radiation at typical doses of around 6 Sv per hour.
• The current European death toll from the incident is estimated between 9,000-16,000. 
• It is predicted that the final toll from the disaster will include 41,000 cancer cases and 4,000 cancer deaths.
• 1990: The radiotherapy accident in Zaragoza, Spain. 
• Patients were treated with an unsafe radiotherapy device. 
• This caused 27 cases of ARS and 11 deaths.
• September 1999: The Tokaimura nuclear accident in Ibaraki, Japan.
• 3 technicians were exposed to high doses of radiation. 
• Hisashi Ouchi received a dose of 17 Sv. He developed ARS and aplastic anaemia. None of his chromosomes could be identified by karyotyping. His white blood cell count was 0. Despite this, he was aggressively treated and resuscitated many times. He lived for 83 days and died in December 1999.
• Masato Shinohara received a dose of 10 Sv. He developed ARS and aplastic anaemia. He received skin grafts. He lived for 7 months and died of in April 2000, from an infection.
• Yutaka Yokokawa received a dose of 3 Sv. He developed ARS and remained in a hospital for 3 months. He is not known to have died.
• The former 2 cases are ethically controversial, because both patients were exposed to lethal doses of radiation, with no chance of recovery. Every effort was made to keep them alive, so their suffering was prolonged. It is unclear whether there was a failure in medical decision making or a utilitarian desire to research the biological effects of severe irradiation.
• November 2006: The poisoning of Alexander Litvinenko in London, UK. 
• On the 1st November 2006, Litvinenko met two former Russian espionage agents. Later that day he developed ARS. Investigations revealed that his body was contaminated with the radioisotope polonium-210. It has been speculated that the radioisotope was sprayed into his teapot by an assassin.
• The estimated initial activity of the ingested material was 4.4Gbq.
• The dose equivalent in his organs was estimated between 20 Gy (alpha radiation) - 100 Gy (alpha radiation). This is equivalent to a dose between 400 Sv - 2000 Sv.
• Litvinenko died on the 23rd of November 2006.

Varicose veins

Disease class: Vascular diseases

Causes

• Venous insufficiency

Hyperoxaluria

Disease class: Kidney diseases

Graft vs Host disease

Disease class: Immune system diseases

Immunologic deficiency syndromes

Disease class: Immune system diseases

Types

• Agammaglobulinaemia
• Ataxia telangiectasia
• Common variable immunodeficiency
• Dysgammaglobulinaemia
• HIV infections
• Deltaretrovirus infections
• Leukocyte-adhesion deficiency syndrome
• Lymphopoenia
• Phagocyte bactericidal dysfunction
• Severe combined immunodeficiency 

This class includes all diseases caused by underactivity of the components of the immune system. 

Patients with these diseases have a significantly increased probability of severe or life-threatening infections. 

Joint loose bodies

Disease class: Joint diseases

Leg length inequality

Disease class:  bone diseases, Developmental

Also known as

• LLI 
• Unequal leg length
• Leg length discrepancy
• LLD

 

Signs

• Abnormal gait
• Obvious assymetry of legs or pelvic tilting due to length inequality
• Measurement of apparent leg length reveals a significant difference between legs
• Measurement of true leg length reveals a significant difference between legs

 

Causes

• Congenital
• Often iatrogenic (e.g. after replacement arthroplasty)

 

Investigations

• X-ray: measurement of bone lengths

Central pontine myelinolysis

 Disease class: brain diseases, Metabolic

Disease class: Demyelinating diseases

 

Consequences

• Locked-in syndrome

 

Causes

• Iatrogenic: Aggressive correction of hyponatraemia. Sodium restoration (e.g. by an infusion of sodium chloride) must be very slow and gradual. Specialist advice should be sought.

Intracranial hypotension

Disease class: Brain diseases

Hoarseness

Disease class: Respiration disorders

Hyperventilation

Disease class: Respiration disorders

Stevens-Johnson syndrome

Disease class: Erythema multiforme

Hypokalaemia

Disease class: Water-electrolyte imbalance

This refers to potassium (kalium) levels in the blood below the reference range.

 

Management

• Diuretics, potassium-sparing
• Potassium, intravenous
• Potassium, oral

 

See also

• Hyperkalaemia 

Hyperkalaemia

Disease class: Water-electrolyte imbalance

This refers to potassium (kalium) levels in the blood above the reference range.

 

Management

• Beta2-agonists
• Calcium and vitamin D
• Glucose (dextrose)
• Insulin

 

See also

• Hypokalaemia

Muscle cramp

Disease class: Muscular diseases 

Hypoaldosteronism

Disease class: Adrenal insufficiency

See also

• Hyperaldosteronism