Haff disease overview

# Overview
Haff disease is the development of rhabdomyolysis (swelling and breakdown of skeletal muscle, with a risk of acute kidney failure) within 24 hours of ingesting fish.

# Historical Perspective
The first case of Haff disease was reported in 1924 in the vicinity of Konigsberg on the Baltic coast, in people staying around the haff; hence the name "Haff disease".  From 1925 to 1940, about 1000 cases were reported not only in humans, but in birds and cats as well, and were linked to the consumption of fish (burbot, eel, and pike).  Only twenty-six cases of Haff disease were reported in the US from 1984 to 2014.  As the standards of living are improving, the availability of fish for consumption is increasing, and thus, resulting in an increased number of cases.

# Pathophysiology
Haff disease is a rare clinical syndrome, the pathophysiology of which remains unclear.  Palytoxin, a heat-stable toxin with thiaminase activity, has been proposed to play a role in the development of this condition.  Due to the heat-stable nature of this toxin, it cannot be inactivated by cooking.

# Causes
The etiology of Haff disease remains unclear, and further investigations are required.

# Differential Diagnosis
Haff disease causes rhabdomyolysis and must be differentiated from other causes of rhabdomyolysis, which may be categorized as physical, non-physical, and genetic factors.  Physical factors include trauma, excessive muscular activity, status epilepticus, high-grade fever, heatstroke, and electric shock.  Non-physical factors include medications, infections, drugs, and electrolyte abnormalities.  Genetic factors consist of autoimmune diseases, metabolic diseases, and various inherited conditions.

# Epidemiology and Demographics
Cases of Haff disease are seen worldwide, but the causative organisms vary with the geographical location.  Burbot, pike, freshwater eel, and whitefish are predominant causative fish in Eastern Europe and Sweden.  Cases of Haff disease in China were related to freshwater pomfret and crayfish.  In Japan, boxfish was associated with Haff disease and in the United States buffalo fish, crayfish and atlantic salmon were the culprits.

# Risk Factors
The major risk factor associated with Haff disease is consumption of aquatic foods (e.g., crayfish, burbot, buffalo fish).

# Natural History, Complications, and Prognosis
Haff disease has an incubation period of eight hours and presents with nausea, vomiting, muscle rigidity, chest pain, diaphoresis, and brown urine (myoglobinuria). Though it is a self-limiting condition with a good prognosis, some cases may develop complications such as acute kidney injury and disseminated intravascular coagulation.

# Diagnosis

## History and Symptoms
Symptoms of Haff disease develop within 24 hours of consumption of cooked seafood. These symptoms include nausea, vomiting, myalgia, muscle rigidity, chest pain, diaphoresis, dyspnea, and brown urine.

## Physical Examination
On examination there may be muscle tenderness, weakness, as well as myoglobinuria.

## Laboratory Findings
The diagnostic criteria for defining a case of Haff disease include a history of consumption of cooked seafood within 24 hours prior to the onset of symptoms, elevated serum CPK, and CK-MB fraction of less than 5%.
Evaluation of Haff disease should include CBC, creatine kinase, serum electrolytes, liver function tests, urine pH, and urinalysis.

## EKG
Haff disease may result in cardiac arrhythmias due to hyperkalemia and hypocalcemia, as a result of rhabdomyolysis. Therefore, it is essential to monitor the patient with an ECG.

## Ultrasound
Hypoechoic areas due to inflammation of the muscles as well as fluid infiltration may be seen in Haff disease.

## Other Diagnostic Studies
Other diagnostic studies are not required for the diagnosis of Haff disease.

# Treatment

## Medical Therapy
The medical therapy of Haff disease consists of managing rhabdomyolysis by aggressive fluid hydration, managing electrolyte abnormalities (hyperkalemia and hypocalcemia), and other supportive care.

## Surgical Therapy
There is no surgical treatment indicated for Haff disease.

## Primary Prevention
The primary prevention of Haff disease is avoiding the consumption of seafood that is associated with Haff disease.